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Sample records for acoustic potential energy

  1. 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.

  2. Problems in Assessment of Wind Energy Potential and Acoustic Noise Distribution when Designing Wind Power Plants

    NASA Astrophysics Data System (ADS)

    Bezrukovs, Valerijs; Bezrukovs, Vladislavs; Levins, Nikolajs

    2011-01-01

    Interest in the use of renewable energy in Latvia is increasing every year. Government support and availability of large unpopulated areas on the coast makes the use of these lands for the placement of large wind power plants (WPP) attractive. The key factors that determine the choice of the location of WPP are reliable information about distribution of the resource of wind energy in this area and the influence of wind turbines on the environment. The paper presents the results of years-long observations on the density fluctuations of wind energy at heights of 10 to 60 m in the area in the Baltic Sea coast in Ventspils and Ainaži. The velocity observations since 2007 have been gathered by measurements complex of the LOGGER 9200 Symphonie type. The results are presented in the form of tables, bar charts and graphs. Extrapolation results of wind velocity and density mean values on heights up to 150 m for the two areas with different terrain types were shown. The distribution of acoustic noise in the vicinity of the WPP was studied and an assessment of its impact on the environment in accordance with the Latvian government requirements was conducted.

  3. 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.

  4. Acoustic sensors using microstructures tunable with energy other than acoustic energy

    DOEpatents

    Datskos, Panagiotis G.

    2005-06-07

    A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

  5. Acoustic sensors using microstructures tunable with energy other than acoustic energy

    DOEpatents

    Datskos, Panagiotis G.

    2003-11-25

    A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

  6. Potential wells for classical acoustic waves

    NASA Astrophysics Data System (ADS)

    Chen, Shi; Lin, ShuYu; Mo, RunYang; Fu, ZhiQiang

    2014-01-01

    The acceleration theorem of Bloch waves is utilized to construct random potential wells for classical acoustic waves in systems composed of alternating `cavities' and `couplers'. One prominent advantage of this method is these `cavities' and `couplers' are all monolayer structures. It allows forming more compact classical potential wells, which leads to the miniaturization of acoustic devices. We systematically investigate properties of harmonic, tangent, hyperbolic function, and square classical potential wells in quasi-periodic superlattices. Results show these classical potential wells are analogues of quantum potential wells. Thus some technologies and concepts in quantum potential well fields may be generalized to classical acoustic wave fields. In addition, some abnormal cases regarding forming classical potential wells are also found.

  7. Method and apparatus for generating acoustic energy

    DOEpatents

    Guerrero, Hector N.

    2002-01-01

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

  8. 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.

  9. Acoustic energy in ducts - Further observations

    NASA Technical Reports Server (NTRS)

    Eversman, W.

    1979-01-01

    The transmission of acoustic energy in uniform ducts carrying uniform flow is investigated with the purpose of clarifying two points of interest. The two commonly used definitions of acoustic 'energy' flux are shown to be related by a Legendre transformation of the Lagrangian density exactly as in deriving the Hamiltonian density in mechanics. In the acoustic case the total energy density and the Hamiltonian density are not the same which accounts for two different 'energy' fluxes. When the duct has acoustically absorptive walls neither of the two flux expressions gives correct results. A reevaluation of the basis of derivation of the energy density and energy flux provides forms which yield consistent results for soft walled ducts.

  10. Identifying Potential Noise Sources within Acoustic Signals

    NASA Astrophysics Data System (ADS)

    Holcomb, Victoria; Lewalle, Jacques

    2013-11-01

    We test a new algorithm for its ability to detect sources of noise within random background. The goal of these tests is to better understand how to identify sources within acoustic signals while simultaneously determining the strengths and weaknesses of the algorithm in question. Unlike previously published algorithms, the antenna method does not pinpoint events by looking for the most energetic portions of a signal. The algorithm searches for the ideal lag combinations between three signals by taking excerpts of possible events. The excerpt with the lowest calculated minimum distance between possible events is how the algorithm identifies sources. At the minimum distance, the events are close in time and frequency. This method can be compared to the cross correlation and denoising methods to better understand its effectiveness. This work is supported in part by Spectral Energies LLC, under an SBIR grant from AFRL, as well as the Syracuse University MAE department.

  11. Acoustic Energy Estimates in Inhomogeneous Moving Media

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Farris, Mark

    1999-01-01

    In ducted fan engine noise research, there is a need for defining a simple and easy to use acoustic energy conservation law to help in quantification of noise control techniques. There is a well known conservation law relating acoustic energy and acoustic energy flux in the case of an isentropic irrotational flow. Several different approaches have been taken to generalize this conservation law. For example, Morfey finds an identity by separating out the irrotational part of the perturbed flow. Myers is able to find a series of indentities by observing an algebraic relationship between the basic conservation of energy equation for a background flow and the underlying equations of motion. In an approximate sense, this algebraic relationship is preserved under perturbation. A third approach which seems to have not been pursued in the literature is a result known as Noether's theorem. There is a Lagrangian formulation for the Euler equation of fluid mechanics. Noether's theorem says that any group action that leaves the Lagrangian action invariant leads to a conserved quantity. This presentation will include a survey of current results regarding acoustic energy and preliminary results on the symmetries of the Lagrangian.

  12. Properties of acoustic energy quantities

    NASA Astrophysics Data System (ADS)

    Uosukainen, Seppo

    1989-09-01

    The sound power of a source is shown to depend on other sources and environment through the coherent and incoherent interaction and on the mounting conditions of the source. The conditions for a source to be a constant power source (being a rare exception amoung sound sources) are defined. A new quantity semianalytic intensity is defined. By its help the mean value, time-dependent, active and reactive intensity are defined in general time-dependent fields. In time harmonic fields the active part of the mean value intensity is rotational. The rotationality is proportional to the polarization vector of particle velocity, the polarization being elliptical in general. The changes of sound field are shown to generate rotationality in all intensity components. The negative pI-indicator is shown to be a possible indication of the rotationality of intensity. Fundamental intensity vortices are defined. The size of the lowest order vortices is of the order of 0.5 to 0.7 (Lambda). A modified J.M.C. method is developed for the basis of the vector and dyadic weighting, the former of which weights the sound pressure and particle velocity differently, and the latter also changes the polarization (or direction) of the particle velocity. Theoretical possibilities of general field modifications and acoustic sink optimization based on these new field reshapers are presented. A new field indicator for intensity measurements is defined. It can be used as a measure of the diffuseness and reactivity as a function of time and observation direction.

  13. Zebra mussel control using acoustic energy

    SciTech Connect

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

    1992-01-01

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

  14. 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.

  15. Acoustical problems in high energy pulsed E-beams lasers

    NASA Technical Reports Server (NTRS)

    Horton, T. E.; Wylie, K. F.

    1976-01-01

    During the pulsing of high energy, CO2, electron beam lasers, a significant fraction of input energy ultimately appears as acoustical disturbances. The magnitudes of these disturbances were quantified by computer analysis. Acoustical and shock impedance data are presented on materials (Rayleigh type) which show promise in controlling acoustical disturbance in E-beam systems.

  16. Potential Competitive Dynamics of Acoustic Ecology.

    PubMed

    Radford, C A; Montgomery, J C

    2016-01-01

    The top predators in coastal marine ecosystems, such as whales, dolphins, seabirds, and large predatory fishes (including sharks), may compete with each other to exploit food aggregations. Finding these patchy food sources and being first to a food patch could provide a significant competitive advantage. Our hypothesis is that food patches have specific sound signatures that marine predators could detect and that acoustic sources and animal sensory capabilities may contribute to competition dynamics. Preliminary analysis shows that diving gannets have a distinct spectral signature between 80 and 200 Hz, which falls within the hearing sensitivity of large pelagic fishes. Therefore, we suggest that diving birds may contribute to the sound signatures of food aggregations, linking competition dynamics both above and below the water surface. PMID:26611047

  17. 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.

  18. Net electron-phonon scattering rates in InN/GaN multiple quantum wells: The effects of an energy dependent acoustic deformation potential

    SciTech Connect

    Xia, H. Patterson, R.; Feng, Y.; Shrestha, S.; Conibeer, G.

    2014-08-11

    The rates of charge carrier relaxation by phonon emission are of substantial importance in the field of hot carrier solar cell, primarily in investigation of mechanisms to slow down hot carrier cooling. In this work, energy and momentum resolved deformation potentials relevant to electron-phonon scattering are computed for wurtzite InN and GaN as well as an InN/GaN multiple quantum well (MQW) superlattice using ab-initio methods. These deformation potentials reveal important features such as discontinuities across the electronic bandgap of the materials and variations over tens of eV. The energy dependence of the deformation potential is found to be very similar for wurtzite nitrides despite differences between the In and Ga pseudopotentials and their corresponding electronic band structures. Charge carrier relaxation by this mechanism is expected to be minimal for electrons within a few eV of the conduction band edge. However, hole scattering at energies more accessible to excitation by solar radiation is possible between heavy and light hole states. Moderate reductions in overall scattering rates are observed in MQW relative to the bulk nitride materials.

  19. Net electron-phonon scattering rates in InN/GaN multiple quantum wells: The effects of an energy dependent acoustic deformation potential

    NASA Astrophysics Data System (ADS)

    Xia, H.; Patterson, R.; Feng, Y.; Shrestha, S.; Conibeer, G.

    2014-08-01

    The rates of charge carrier relaxation by phonon emission are of substantial importance in the field of hot carrier solar cell, primarily in investigation of mechanisms to slow down hot carrier cooling. In this work, energy and momentum resolved deformation potentials relevant to electron-phonon scattering are computed for wurtzite InN and GaN as well as an InN/GaN multiple quantum well (MQW) superlattice using ab-initio methods. These deformation potentials reveal important features such as discontinuities across the electronic bandgap of the materials and variations over tens of eV. The energy dependence of the deformation potential is found to be very similar for wurtzite nitrides despite differences between the In and Ga pseudopotentials and their corresponding electronic band structures. Charge carrier relaxation by this mechanism is expected to be minimal for electrons within a few eV of the conduction band edge. However, hole scattering at energies more accessible to excitation by solar radiation is possible between heavy and light hole states. Moderate reductions in overall scattering rates are observed in MQW relative to the bulk nitride materials.

  20. Energy Efficient Engine acoustic supporting technology report

    NASA Technical Reports Server (NTRS)

    Lavin, S. P.; Ho, P. Y.

    1985-01-01

    The acoustic development of the Energy Efficient Engine combined testing and analysis using scale model rigs and an integrated Core/Low Spool demonstration engine. The scale model tests show that a cut-on blade/vane ratio fan with a large spacing (S/C = 2.3) is as quiet as a cut-off blade/vane ratio with a tighter spacing (S/C = 1.27). Scale model mixer tests show that separate flow nozzles are the noisiest, conic nozzles the quietest, with forced mixers in between. Based on projections of ICLS data the Energy Efficient Engine (E3) has FAR 36 margins of 3.7 EPNdB at approach, 4.5 EPNdB at full power takeoff, and 7.2 EPNdB at sideline conditions.

  1. Acoustic Solitary Waves and Sagdeev Potential Triple Roots

    SciTech Connect

    Hellberg, M. A.; Baluku, T. K.; Verheest, F.

    2010-12-14

    Both KdV theory and the standard pseudopotential theory require that solitons and double layers be explicitly super-acoustic, with the pseudopotential {psi}({phi},M) having a maximum at the origin. Recent studies of a variety of different three-component plasmas have shown that they may support finite amplitude solitons at the true acoustic speed of the plasma configuration, M{sub s}. These are associated with triple roots of the Sagdeev potential, and the usual soliton condition is replaced by {psi}''(0,M){<=}0. Sagdeev potentials for speeds marginally greater than M{sub s} then represent solitons of both polarities, one whose amplitude vanishes at M{sub s}(KdV-like), while the other is necessarily finite at M{sub s}('nonKdV-like'). Such coexistence regions have been observed to be linked to a critical plasma compositional parameter value for which {psi}'''(0,M{sub s}) = 0.

  2. Fundamental Potential for Acoustic Microscopy Evaluation of Dental Tissues

    NASA Astrophysics Data System (ADS)

    Denisova, L. A.; Maev, R. Gr.; Rusanov, F. S.; Maeva, A. R.; Denisov, A. F.; Gavrilov, D. Yu.; Bakulin, E. Yu.; Severin, F. M.

    Comprehensive analysis of the present-day acoustic microscopy experimental approaches from the standpoint of their potential application in dental research and diagnostics has been performed. Whole extracted human teeth and specially prepared dental tissue samples have been investigated. The results of the study demonstrate that there are several experimental techniques that can be used for precise quantitative evaluation of the tissues local mechanical properties in flat-parallel teeth slices, for the pathomorphological investigation of the tissues strength spatial distribution in flat cuts. In the whole tooth, the acoustic microscopy techniques allow us to precisely measure the enamel and dentine layers thickness, the distance between the external surface and pulp, to reveal hidden caries and restoration disbonding. These opportunities form a real ground for the further design of the special acousto-microscopical methods and new equipment for the clinical diagnostics

  3. Acoustic Communication in Fishes and Potential Effects of Noise.

    PubMed

    Mann, David A

    2016-01-01

    Many soniferous fishes such as cods and groupers are commercially important. Sounds are produced during courtship and spawning, and there is the potential for aquatic noise to interfere with critical behaviors and affect populations. There are few data on the response of wild populations of sound-producing fishes to acoustic noise. New motion and sound exposure fish tags could be used to assess the behavioral responses of large numbers of fish to noise exposure. Many factors, such as fishing mortality and environmental variability in prey supply, could also affect populations and potentially interact with the behavioral responses to noise. PMID:26611018

  4. 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.

  5. Ocular vestibular evoked myogenic potentials in patients with acoustic neuroma.

    PubMed

    Piras, Gianluca; Brandolini, Cristina; Castellucci, Andrea; Modugno, Giovanni Carlo

    2013-02-01

    To assess the usefulness of vestibular testing in patients with acoustic neuroma, considering two main aspects: to compare diagnostic sensitivity of the current vestibular tests, especially considering ocular vestibular evoked myogenic potentials (OVEMPs) and to identify pre-operative localization of the tumor (inferior vestibular nerve vs. superior vestibular nerve) only with the help of vestibular electrophysiological data. Twenty-six patients with unilateral acoustic neuroma (mainly intracanalicular type) were studied with a full audio-vestibular test battery (pure tone and speech audiometry, caloric bithermal test, vibration-induced nystagmus test (VIN), cervical and OVEMPs). 18 patients (69 %) showed abnormal caloric responses. 12 patients (46.2 %) showed a pattern of VIN test suggestive of vestibular asymmetry. 16 patients (61.5 %) showed abnormal OVEMPs (12 only to AC, 4 both to AC and BC). 10 patients (38.5 %) showed abnormal cervical vestibular evoked myogenic potentials (5 both to AC and BC, 5 only to AC). In one case, results of vestibular evoked potentials and caloric test were confirmed by intra-operative and post-operative findings. Results of electrophysiological tests in AN patients could be helpful for planning the proper surgical approach, considering that sensitivity of every exam is quite low in intracanalicular lesion; clinical data allow a better interpretation of vestibular evoked myogenic potentials. PMID:22526579

  6. Acoustic energy-driven fluid pump and method

    SciTech Connect

    Janus, Michael C.; Richards, George A.; Robey, Edward H.

    1997-12-01

    Bulk fluid motion is promoted in a gaseous fluid contained within a conduit system provided with a diffuser without the need for a mean pressure differential across the conduit system. The contacting of the gaseous fluid with unsteady energy at a selected frequency and pressure amplitude induces fluid flow through the conical diffuser. The unsteady energy can be provided by pulse combustors, thermoacoustic engines, or acoustic energy generators such as acoustic speakers.

  7. Potential of surface acoustic wave biosensors for early sepsis diagnosis.

    PubMed

    Csete, Marie; Hunt, William D

    2013-08-01

    Early diagnosis of sepsis is a difficult problem for intensivists and new biomarkers for early diagnosis have been difficult to come by. Here we discuss the potential of adapting a technology from the electronics industry, surface acoustic wave (SAW) sensors, for diagnosis of multiple markers of sepsis in real time, using non-invasive assays of exhaled breath condensate. The principles and advantages of the SAW technology are reviewed as well as a proposed plan for adapting this flexible technology to early sepsis detection. PMID:23471596

  8. Acoustic energy transmission in cast iron pipelines

    NASA Astrophysics Data System (ADS)

    Kiziroglou, Michail E.; Boyle, David E.; Wright, Steven W.; Yeatman, Eric M.

    2015-12-01

    In this paper we propose acoustic power transfer as a method for the remote powering of pipeline sensor nodes. A theoretical framework of acoustic power propagation in the ceramic transducers and the metal structures is drawn, based on the Mason equivalent circuit. The effect of mounting on the electrical response of piezoelectric transducers is studied experimentally. Using two identical transducer structures, power transmission of 0.33 mW through a 1 m long, 118 mm diameter cast iron pipe, with 8 mm wall thickness is demonstrated, at 1 V received voltage amplitude. A near-linear relationship between input and output voltage is observed. These results show that it is possible to deliver significant power to sensor nodes through acoustic waves in solid structures. The proposed method may enable the implementation of acoustic - powered wireless sensor nodes for structural and operation monitoring of pipeline infrastructure.

  9. Enhanced vibration based energy harvesting using embedded acoustic black holes

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Semperlotti, F.; Conlon, S. C.

    2014-03-01

    In this paper, we investigate the use of dynamic structural tailoring via the concept of an Acoustic Black Hole (ABH) to enhance the performance of piezoelectric based energy harvesting from operational mechanical vibrations. The ABH is a variable thickness structural feature that can be embedded in the host structure allowing a smooth reduction of the phase velocity while minimizing the amplitude of reflected waves. The ABH thickness variation is typically designed according to power-law profiles. As a propagating wave enters the ABH, it is progressively slowed down while its wavelength is compressed. This effect results in structural areas with high energy density that can be exploited effectively for energy harvesting. The potential of ABH for energy harvesting is shown via a numerical study based on fully coupled finite element electromechanical models of an ABH tapered plate with surface mounted piezo-transducers. The performances of the novel design are evaluated by direct comparison with a non-tapered structure in terms of energy ratios and attenuation indices. Results show that the tailored structural design allows a drastic increase in the harvested energy both for steady state and transient excitation. Performance dependencies of key design parameters are also investigated.

  10. Characterization of energy trapping in a bulk acoustic wave resonator

    NASA Astrophysics Data System (ADS)

    Kokkonen, Kimmo; Meltaus, Johanna; Pensala, Tuomas; Kaivola, Matti

    2010-12-01

    Acoustic wave fields both within the active electrode area of a solidly mounted 1.8 GHz bulk acoustic wave resonator, and around it in the surrounding region, are measured using a heterodyne laser interferometer. Plate-wave dispersion diagrams for both regions are extracted from the measurement data. The experimental dispersion data reveal the cutoff frequencies of the acoustic vibration modes in the region surrounding the resonator, and, therefore, the energy trapping range of the resonator can readily be determined. The measured dispersion properties of the surrounding region, together with the abruptly diminishing amplitude of the dispersion curves in the resonator, signal the onset of acoustic leakage from the resonator. This information is important for verifying and further developing the simulation tools used for the design of the resonators. Experimental wave field images, dispersion diagrams for both regions, and the threshold for energy leakage are discussed.

  11. Detection of Large Acoustic Energy Flux in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Bello González, N.; Franz, M.; Martínez Pillet, V.; Bonet, J. A.; Solanki, S. K.; del Toro Iniesta, J. C.; Schmidt, W.; Gandorfer, A.; Domingo, V.; Barthol, P.; Berkefeld, T.; Knölker, M.

    2010-11-01

    We study the energy flux carried by acoustic waves excited by convective motions at sub-photospheric levels. The analysis of high-resolution spectropolarimetric data taken with IMaX/SUNRISE provides a total energy flux of ~6400-7700 W m-2 at a height of ~250 km in the 5.2-10 mHz range, i.e., at least twice the largest energy flux found in previous works. Our estimate lies within a factor of two of the energy flux needed to balance radiative losses from the chromosphere according to the estimates of Anderson & Athay and revives interest in acoustic waves for transporting energy to the chromosphere. The acoustic flux is mainly found in the intergranular lanes but also in small rapidly evolving granules and at the bright borders, forming dark dots and lanes of splitting granules.

  12. Converting acoustic energy into useful other energy forms

    DOEpatents

    Putterman, Seth J.; Barber, Bradley Paul; Hiller, Robert Anthony; Lofstedt, Ritva Maire Johanna

    1997-01-01

    Sonoluminescence is an off-equilibrium phenomenon in which the energy of a resonant sound wave in a liquid is highly concentrated so as to generate flashes of light. The conversion of sound to light represents an energy amplification of eleven orders of magnitude. The flashes which occur once per cycle of the audible or ultrasonic sound fields can be comprised of over one million photons and last for less 100 picoseconds. The emission displays a clocklike synchronicity; the jitter in time between consecutive flashes is less than fifty picoseconds. The emission is blue to the eye and has a broadband spectrum increasing from 700 nanometers to 200 nanometers. The peak power is about 100 milliWatts. The initial stage of the energy focusing is effected by the nonlinear oscillations of a gas bubble trapped in the liquid. For sufficiently high drive pressures an imploding shock wave is launched into the gas by the collapsing bubble. The reflection of the shock from its focal point results in high temperatures and pressures. The sonoluminescence light emission can be sustained by sensing a characteristic of the emission and feeding back changes into the driving mechanism. The liquid is in a sealed container and the seeding of the gas bubble is effected by locally heating the liquid after sealing the container. Different energy forms than light can be obtained from the converted acoustic energy. When the gas contains deuterium and tritium there is the feasibility of the other energy form being fusion, namely including the generation of neutrons.

  13. Topics in electromagnetic, acoustic, and potential scattering theory

    NASA Astrophysics Data System (ADS)

    Nuntaplook, Umaporn

    With recent renewed interest in the classical topics of both acoustic and electromagnetic aspects for nano-technology, transformation optics, fiber optics, metamaterials with negative refractive indices, cloaking and invisibility, the topic of time-independent scattering theory in quantum mechanics is becoming a useful field to re-examine in the above contexts. One of the key areas of electromagnetic theory scattering of plane electromagnetic waves --- is based on the properties of the refractive indices in the various media. It transpires that the refractive index of a medium and the potential in quantum scattering theory are intimately related. In many cases, understanding such scattering in radially symmetric media is sufficient to gain insight into scattering in more complex media. Meeting the challenge of variable refractive indices and possibly complicated boundary conditions therefore requires accurate and efficient numerical methods, and where possible, analytic solutions to the radial equations from the governing scalar and vector wave equations (in acoustics and electromagnetic theory, respectively). Until relatively recently, researchers assumed a constant refractive index throughout the medium of interest. However, the most interesting and increasingly useful cases are those with non-constant refractive index profiles. In the majority of this dissertation the focus is on media with piecewise constant refractive indices in radially symmetric media. The method discussed is based on the solution of Maxwell's equations for scattering of plane electromagnetic waves from a dielectric (or "transparent") sphere in terms of the related Helmholtz equation. The main body of the dissertation (Chapters 2 and 3) is concerned with scattering from (i) a uniform spherical inhomogeneity embedded in an external medium with different properties, and (ii) a piecewise-uniform central inhomogeneity in the external medium. The latter results contain a natural generalization of

  14. Sound insulation and energy harvesting based on acoustic metamaterial plate

    NASA Astrophysics Data System (ADS)

    Assouar, Badreddine; Oudich, Mourad; Zhou, Xiaoming

    2015-03-01

    The emergence of artificially designed sub-wavelength acoustic materials, denoted acoustic metamaterials (AMM), has significantly broadened the range of materials responses found in nature. These engineered materials can indeed manipulate sound/vibration in surprising ways, which include vibration/sound insulation, focusing, cloaking, acoustic energy harvesting …. In this work, we report both on the analysis of the airborne sound transmission loss (STL) through a thin metamaterial plate and on the possibility of acoustic energy harvesting. We first provide a theoretical study of the airborne STL and confronted them to the structure-borne dispersion of a metamaterial plate. Second, we propose to investigate the acoustic energy harvesting capability of the plate-type AMM. We have developed semi-analytical and numerical methods to investigate the STL performances of a plate-type AMM with an airborne sound excitation having different incident angles. The AMM is made of silicone rubber stubs squarely arranged in a thin aluminum plate, and the STL is calculated at low-frequency range [100Hz to 3kHz] for an incoming incident sound pressure wave. The obtained analytical and numerical STL present a very good agreement confirming the reliability of developed approaches. A comparison between computed STL and the band structure of the considered AMM shows an excellent agreement and gives a physical understanding of the observed behavior. On another hand, the acoustic energy confinement in AMM with created defects with suitable geometry was investigated. The first results give a general view for assessing the acoustic energy harvesting performances making use of AMM.

  15. Hybrid acoustic energy harvesting using combined electromagnetic and piezoelectric conversion.

    PubMed

    Khan, Farid Ullah; Izhar

    2016-02-01

    This paper reports a novel hybrid acoustic energy harvester. The harvester utilizes both the electromagnetic and piezoelectric conversion mechanisms simultaneously to convert the ambient acoustical noise into electrical power for self-powered wireless sensor nodes. The proposed harvester is comprised of a Helmholtz resonator, two magnets mounted on a piezoelectric plate, and a wound coil located under the magnets. The harvester is characterized both under harmonic and real random acoustical excitations. In-lab, under harmonic acoustical excitation at a sound pressure level of 130 dB and frequency of 2.1 kHz, an optimum power of 2.86 μW (at 114 Ω optimum load) is obtained from electromagnetic conversion and 50 μW (at 1000 Ω optimum load) is generated by the piezoelectric harvester's part. Moreover, in real acoustical environment of a domestic electric generator the peak voltages of 40 and 123 mV are produced by the electromagnetic and piezoelectric portions of the acoustic energy harvester. PMID:26931884

  16. Hybrid acoustic energy harvesting using combined electromagnetic and piezoelectric conversion

    NASA Astrophysics Data System (ADS)

    Khan, Farid Ullah; Izhar

    2016-02-01

    This paper reports a novel hybrid acoustic energy harvester. The harvester utilizes both the electromagnetic and piezoelectric conversion mechanisms simultaneously to convert the ambient acoustical noise into electrical power for self-powered wireless sensor nodes. The proposed harvester is comprised of a Helmholtz resonator, two magnets mounted on a piezoelectric plate, and a wound coil located under the magnets. The harvester is characterized both under harmonic and real random acoustical excitations. In-lab, under harmonic acoustical excitation at a sound pressure level of 130 dB and frequency of 2.1 kHz, an optimum power of 2.86 μW (at 114 Ω optimum load) is obtained from electromagnetic conversion and 50 μW (at 1000 Ω optimum load) is generated by the piezoelectric harvester's part. Moreover, in real acoustical environment of a domestic electric generator the peak voltages of 40 and 123 mV are produced by the electromagnetic and piezoelectric portions of the acoustic energy harvester.

  17. On the relationship between acoustic energy density flux near the jet and far field acoustic intensity

    NASA Technical Reports Server (NTRS)

    Maestrello, L.

    1973-01-01

    The relationship between the distribution of the outflow of acoustic energy over the jet boundary and the far-field directivity and intensity distribution is established by measurement and analysis. The numerical and experimental procedures involved have been checked out by using a known source. The results indicate that the acoustic power output per unit length of the jet, in the region from which the sound emanates, peaks at approximately 9 diameters downstream. The acoustic emission for a jet Strouhal number of about 0.3 exceeds the emission for all other Strouhal numbers nearly everywhere along the measurement plane. However, the far-field peak intensity distribution obtained from the contribution of each station was found to depend on the spatial extent of the region where sound emanates from the jet, which, in turn, depends more on the far-field angle than on the Strouhal number. The implications of these results for sound suppression techniques are discussed.

  18. Baryon Acoustic Oscillation Intensity Mapping of Dark Energy

    NASA Astrophysics Data System (ADS)

    Chang, Tzu-Ching; Pen, Ue-Li; Peterson, Jeffrey B.; McDonald, Patrick

    2008-03-01

    The expansion of the Universe appears to be accelerating, and the mysterious antigravity agent of this acceleration has been called “dark energy.” To measure the dynamics of dark energy, baryon acoustic oscillations (BAO) can be used. Previous discussions of the BAO dark energy test have focused on direct measurements of redshifts of as many as 109 individual galaxies, by observing the 21 cm line or by detecting optical emission. Here we show how the study of acoustic oscillation in the 21 cm brightness can be accomplished by economical three-dimensional intensity mapping. If our estimates gain acceptance they may be the starting point for a new class of dark energy experiments dedicated to large angular scale mapping of the radio sky, shedding light on dark energy.

  19. Baryon acoustic oscillation intensity mapping of dark energy.

    PubMed

    Chang, Tzu-Ching; Pen, Ue-Li; Peterson, Jeffrey B; McDonald, Patrick

    2008-03-01

    The expansion of the Universe appears to be accelerating, and the mysterious antigravity agent of this acceleration has been called "dark energy." To measure the dynamics of dark energy, baryon acoustic oscillations (BAO) can be used. Previous discussions of the BAO dark energy test have focused on direct measurements of redshifts of as many as 10(9) individual galaxies, by observing the 21 cm line or by detecting optical emission. Here we show how the study of acoustic oscillation in the 21 cm brightness can be accomplished by economical three-dimensional intensity mapping. If our estimates gain acceptance they may be the starting point for a new class of dark energy experiments dedicated to large angular scale mapping of the radio sky, shedding light on dark energy. PMID:18352692

  20. A comparative analysis of acoustic energy models for churches.

    PubMed

    Berardi, Umberto; Cirillo, Ettore; Martellotta, Francesco

    2009-10-01

    Different models to improve prediction of energy-based acoustic parameters in churches have been proposed by different researchers [E. Cirillo and F. Martellotta, J. Acoust. Soc. Am. 118, 232-248 (2005); T. Zamarreño et al., J. Acoust. Soc. Am. 121, 234-250 (2006)]. They all suggested variations to the "revised" theory proposed by Barron and Lee [J. Acoust. Soc. Am. 84, 618-628 (1988)], starting from experimental observations. The present paper compares these models and attempts to generalize their use taking advantage of the measurements carried out in 24 Italian churches differing in style, typology, and location. The whole sample of churches was divided into two groups. The first was used to fine-tune existing models, with particular reference to the "mu model," which was originally tested only on Mudejar-Gothic churches. Correlations between model parameters and major typological and architectural factors were found, leading to a classification that greatly simplifies parameter choice. Finally, the reliability of each model was verified on the rest of the sample, showing that acoustic parameters can be predicted with reasonable accuracy provided that one of the specifically modified theories is used. The results show that the model requiring more input parameters performs slightly better than the other which, conversely, is simpler to apply. PMID:19813798

  1. 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).

  2. Array of piezoelectric wires in acoustic energy harvesting

    NASA Astrophysics Data System (ADS)

    Golestanyan, Edvin

    An acoustic energy harvesting mechanism to harvest a travelling sound wave at a low audible frequency (180 ˜ 200Hz) is further developed and studied both experimentally and numerically. The acoustic energy harvester in this study consists of a quarter-wavelength straight tube resonator and multiple piezoelectric oscillators in wire and plate shapes placed inside the tube. When the tube resonator is excited by an incident sound at its acoustic resonant frequency, the amplified acoustic pressure inside the tube drives the vibration motions of piezoelectric oscillators, resulting in generating electricity. It has been found that a single piezoelectric plate generates more power than a wire, but with placing in multiple-rows piezoelectric wires more power is produced. Parallel and series connections of multiple piezoelectric oscillators have also been studied and expressions for calculating optimum loading resistance have been presented. It has been found that the series connection generates more power than parallel connection. As the number of piezoelectric oscillators increases, the magnitude of the single loading resistance decreases. The decrease of loading resistance is more intense in multiple wires than in multiple plates and in parallel connection than in series connection.

  3. Experimental study of the potential of multichannel acoustic thermotomography

    NASA Astrophysics Data System (ADS)

    Krotov, Eugene V.; Xenophontov, S. Y.; Mansfeld, Anatoly D.; Reyman, Alexander M.; Sanin, A. G.

    2001-06-01

    The results of experimental studies of 2D temperature profiles reconstruction inside soft tissues are presented. The 2D images are obtained as the result of mathematical data processing in multichannel scanning acoustic thermotomograph (AT). Operation of this device is based on the receiving of weak acoustic emission produced by thermal motion of medium particles. The intensity of received signal is proportional to the acoustical brightness temperature of emitting object, i.e. to its temperature and sound absorption. Some evident applications of this method are related with early tumor detection and internal temperature measurement during hyperthermal treatment. This kind of passive scanning provides great safety of investigation combined with rather good spatial resolution due to short wavelength and high directivity of AT antenna. Our experiments demonstrated localization of overheated phantom objects inside tissue-like absorbing media with temperature contrast about 0.4 K and 2 mm resolution at 2D images with area size 210x40 mm. The advantages and possible applications of this kind of clinical investigations are illustrated by the results of in vivo experiments on the variation of acoustic brightness temperature of human limbs and liver during some physiological tests. This work was supported by RFBR (project #00-02-16600).

  4. Simulation chain for acoustic ultra-high energy neutrino detectors

    NASA Astrophysics Data System (ADS)

    Neff, M.; Anton, G.; Enzenhöfer, A.; Graf, K.; Hößl, J.; Katz, U.; Lahmann, R.

    2013-10-01

    Acoustic neutrino detection is a promising approach for large-scale ultra-high energy neutrino detectors in water. In this paper, a Monte Carlo simulation chain for acoustic neutrino detection devices in water is presented. It is designed within the SeaTray/IceTray software framework. Its modular architecture is highly flexible and makes it easy to adapt to different environmental conditions, detector geometries, and hardware. The simulation chain covers the generation of the acoustic pulse produced by a neutrino interaction and the propagation to the sensors within the detector. In this phase of the development, ambient and transient noise models for the Mediterranean Sea and simulations of the data acquisition hardware, similar to the one used in ANTARES/AMADEUS, are implemented. A pre-selection scheme for neutrino-like signals based on matched filtering is employed, as it can be used for on-line filtering. To simulate the whole processing chain for experimental data, signal classification and acoustic source reconstruction algorithms are integrated. In this contribution, an overview of the design and capabilities of the simulation chain will be given, and some applications and preliminary studies will be presented.

  5. A hydrophone prototype for ultra high energy neutrino acoustic detection

    NASA Astrophysics Data System (ADS)

    Cotrufo, A.; Plotnikov, A.; Yershova, O.; Anghinolfi, M.; Piombo, D.

    2009-06-01

    The design of an air-backed fiber-optic hydrophone is presented. With respect to the previous models this prototype is optimized to provide a bandwidth sufficiently large to detect acoustic signals produced by high energy hadronic showers in water. In addiction to the geometrical configuration and to the choice of the materials, the preliminary results of the measured performances in air are presented.

  6. 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.

  7. Alaska's renewable energy potential.

    SciTech Connect

    Not Available

    2009-02-01

    This paper delivers a brief survey of renewable energy technologies applicable to Alaska's climate, latitude, geography, and geology. We first identify Alaska's natural renewable energy resources and which renewable energy technologies would be most productive. e survey the current state of renewable energy technologies and research efforts within the U.S. and, where appropriate, internationally. We also present information on the current state of Alaska's renewable energy assets, incentives, and commercial enterprises. Finally, we escribe places where research efforts at Sandia National Laboratories could assist the state of Alaska with its renewable energy technology investment efforts.

  8. Device and method for generating a beam of acoustic energy from a borehole, and applications thereof

    SciTech Connect

    Vu, Cung Khac; Sinha, Dipen N; Pantea, Cristian; Nihei, Kurt T; Schmitt, Denis P; Skelt, Christopher

    2013-10-01

    In some aspects of the invention, a method of generating a beam of acoustic energy in a borehole is disclosed. The method includes generating a first acoustic wave at a first frequency; generating a second acoustic wave at a second frequency different than the first frequency, wherein the first acoustic wave and second acoustic wave are generated by at least one transducer carried by a tool located within the borehole; transmitting the first and the second acoustic waves into an acoustically non-linear medium, wherein the composition of the non-linear medium produces a collimated beam by a non-linear mixing of the first and second acoustic waves, wherein the collimated beam has a frequency based upon a difference between the first frequency and the second frequency; and transmitting the collimated beam through a diverging acoustic lens to compensate for a refractive effect caused by the curvature of the borehole.

  9. Nonlinear optimization of acoustic energy harvesting using piezoelectric devices.

    PubMed

    Lallart, Mickaeël; Guyomar, Daniel; Richard, Claude; Petit, Lionel

    2010-11-01

    In the first part of the paper, a single degree-of-freedom model of a vibrating membrane with piezoelectric inserts is introduced and is initially applied to the case when a plane wave is incident with frequency close to one of the resonance frequencies. The model is a prototype of a device which converts ambient acoustical energy to electrical energy with the use of piezoelectric devices. The paper then proposes an enhancement of the energy harvesting process using a nonlinear processing of the output voltage of piezoelectric actuators, and suggests that this improves the energy conversion and reduces the sensitivity to frequency drifts. A theoretical discussion is given for the electrical power that can be expected making use of various models. This and supporting experimental results suggest that a nonlinear optimization approach allows a gain of up to 10 in harvested energy and a doubling of the bandwidth. A model is introduced in the latter part of the paper for predicting the behavior of the energy-harvesting device with changes in acoustic frequency, this model taking into account the damping effect and the frequency changes introduced by the nonlinear processes in the device. PMID:21110569

  10. Effects of high activation energies on acoustic timescale detonation initiation

    NASA Astrophysics Data System (ADS)

    Regele, J. D.; Kassoy, D. R.; Vasilyev, O. V.

    2012-08-01

    Acoustic timescale Deflagration-to-Detonation Transition (DDT) has been shown to occur through the generation of compression waves emitted by a hot spot or reaction centre where the pressure and temperature increase with little diminution of density. In order to compensate for the multi-scale nature of the physico-chemical processes, previous numerical simulations in this area have been limited to relatively small activation energies. In this work, a computational study investigates the effect of increased activation energy on the time required to form a detonation wave and the change in behaviour of each hot spot as the activation energy is increased. The simulations use a localised spatially distributed thermal power deposition of limited duration into a finite volume of reactive gas to facilitate DDT. The Adaptive Wavelet-Collocation Method is used to solve efficiently the 1-D reactive Euler equations with one-step Arrhenius kinetics. The DDT process as described in previous work is characterised by the formation of hot spots during an initial transient period, explosion of the hot spots and creation of an accelerating reaction front that reaches the lead shock and forms an overdriven detonation wave. Current results indicate that as the activation energy is raised the chemical heat release becomes more temporally distributed. Hot spots that produce an accelerating reaction front with low activation energies change behaviour with increased activation energy so that no accelerating reaction front is created. An acoustic timescale ratio is defined that characterises the change in behaviour of each hot spot.

  11. Treated cabin acoustic prediction using statistical energy analysis

    NASA Technical Reports Server (NTRS)

    Yoerkie, Charles A.; Ingraham, Steven T.; Moore, James A.

    1987-01-01

    The application of statistical energy analysis (SEA) to the modeling and design of helicopter cabin interior noise control treatment is demonstrated. The information presented here is obtained from work sponsored at NASA Langley for the development of analytic modeling techniques and the basic understanding of cabin noise. Utility and executive interior models are developed directly from existing S-76 aircraft designs. The relative importance of panel transmission loss (TL), acoustic leakage, and absorption to the control of cabin noise is shown using the SEA modeling parameters. It is shown that the major cabin noise improvement below 1000 Hz comes from increased panel TL, while above 1000 Hz it comes from reduced acoustic leakage and increased absorption in the cabin and overhead cavities.

  12. Enhanced output power by eigenfrequency shift in acoustic energy harvester

    NASA Astrophysics Data System (ADS)

    Li, Bin; You, Jeong Ho

    2014-04-01

    In our previous studies, multiple piezoelectric cantilever plates were placed inside a quarter-wavelength straight tube resonator to harvest low frequency acoustic energy. To investigate the modification of eigenmodes in the tube resonator due to the presence of piezoelectric plates, the eigenfrequency shift properties by introducing single and multiple rectangular blockages in open-closed ducts are studied by using 1D segmented Helmholtz equations, Webster horn equation, and finite element simulations. The first-mode eigenfrequency of the duct is reduced when the blockage is placed near the open inlet. The decrease of eigenfrequency leads to the enhancement of absorbed acoustic power in the duct. Furthermore, the first half of the tube resonator possesses high pressure gradient resulting in larger driving forces for the vibration motion of piezoelectric plates. Therefore, in our harvesters, it is better to place the piezoelectric plates in the first half of the tube resonator to obtain high output voltage and power.

  13. Acoustic metamaterials capable of both sound insulation and energy harvesting

    NASA Astrophysics Data System (ADS)

    Li, Junfei; Zhou, Xiaoming; Huang, Guoliang; Hu, Gengkai

    2016-04-01

    Membrane-type acoustic metamaterials are well known for low-frequency sound insulation. In this work, by introducing a flexible piezoelectric patch, we propose sound-insulation metamaterials with the ability of energy harvesting from sound waves. The dual functionality of the metamaterial device has been verified by experimental results, which show an over 20 dB sound transmission loss and a maximum energy conversion efficiency up to 15.3% simultaneously. This novel property makes the metamaterial device more suitable for noise control applications.

  14. Acoustic Energy: An Innovative Technology for Stimulating Oil Wells

    SciTech Connect

    Edgar, Dorland E.; Peters, Robert W.; Johnson, Donald O.; Paulsen, P. David; Roberts, Wayne

    2006-04-30

    application of acoustic energy (sonication) significantly reduced the viscosity of crude oils, and the amount of viscosity reduction resulting is greater for more viscous, heavy crude oils than it is for less viscous, light crude oils. (2) Test results showed that after being heated, resulting viscosity reductions were not sustained following treatment to the extent that post-sonication reductions were sustained. (3) The maximum viscosity reductions in Oils 1, 2, and 3 due to sonication were 43%, 76%, and 6%, respectively. Samples of Oil 2 associated with larger viscosity reductions often exhibited a definite water separation layer follow the tests, whereas reductions of approximately 23% were measured when this separation was not observed. (4) It was observed that neither horn design nor the reduction of input power by 25% had very little effect on the ability of sonication to alter crude oil viscosity. (5) The chemical additives produced a range of viscosity reduction from 37% to a maximum of 94% with the largest reductions being facilitated by the abundant water present Oil 2. If the Oil 2 results are not considered, the maximum reduction was 73%. The effects of the additives and sonication are enhanced by each other. (6) In only one test did the viscosity return to as much as 50% of the pre-treatment value during a period of 30 days following treatment; recovery was much less in all other cases. Therefore, more than half of the viscosity reduction was maintained for a month without additional treatment. (7) Possible applications, market potential, and economic value of the implementation of a mature sonication technology within the petroleum industry were identified, and it was estimated that the potential exists that more than a billion barrels of oil could be upgraded or produced annually as a result. The project results successfully demonstrated that sonication alone and in combination with chemical additives can effectively reduce the viscosity of crude oils having a

  15. Diffusive Propagation of Energy in a Non-acoustic Chain

    NASA Astrophysics Data System (ADS)

    Komorowski, Tomasz; Olla, Stefano

    2016-08-01

    We consider a non-acoustic chain of harmonic oscillators with the dynamics perturbed by a random local exchange of momentum, such that energy and momentum are conserved. The macroscopic limits of the energy density, momentum and the curvature (or bending) of the chain satisfy a system of evolution equations. We prove that, in a diffusive space-time scaling, the curvature and momentum evolve following a linear system that corresponds to a damped Euc(uler)-Buc(ernoulli) beam equation. The macroscopic energy density evolves following a non linear diffusive equation. In particular, the energy transfer is diffusive in this dynamics. This provides a first rigorous example of a normal diffusion of energy in a one dimensional dynamics that conserves the momentum.

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

    NASA Technical Reports Server (NTRS)

    Popinceanu, N. G.; Kremmer, I.

    1974-01-01

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

  17. Acoustic-Seismic Coupling of Broadband Signals - Analysis of Potential Disturbances during CTBT On-Site Inspection Measurements

    NASA Astrophysics Data System (ADS)

    Liebsch, Mattes; Altmann, Jürgen

    2015-04-01

    For the verification of the Comprehensive Nuclear Test Ban Treaty (CTBT) the precise localisation of possible underground nuclear explosion sites is important. During an on-site inspection (OSI) sensitive seismic measurements of aftershocks can be performed, which, however, can be disturbed by other signals. To improve the quality and effectiveness of these measurements it is essential to understand those disturbances so that they can be reduced or prevented. In our work we focus on disturbing signals caused by airborne sources: When the sound of aircraft (as often used by the inspectors themselves) hits the ground, it propagates through pores in the soil. Its energy is transferred to the ground and soil vibrations are created which can mask weak aftershock signals. The understanding of the coupling of acoustic waves to the ground is still incomplete. However, it is necessary to improve the performance of an OSI, e.g. to address potential consequences for the sensor placement, the helicopter trajectories etc. We present our recent advances in this field. We performed several measurements to record sound pressure and soil velocity produced by various sources, e.g. broadband excitation by jet aircraft passing overhead and signals artificially produced by a speaker. For our experimental set-up microphones were placed close to the ground and geophones were buried in different depths in the soil. Several sensors were shielded from the directly incident acoustic signals by a box coated with acoustic damping material. While sound pressure under the box was strongly reduced, the soil velocity measured under the box was just slightly smaller than outside of it. Thus these soil vibrations were mostly created outside the box and travelled through the soil to the sensors. This information is used to estimate characteristic propagation lengths of the acoustically induced signals in the soil. In the seismic data we observed interference patterns which are likely caused by the

  18. [Unconscious Acoustical Stimuli Effects on Event-related Potentials in Humans].

    PubMed

    Kopeikina, E A; Choroshich, V V; Aleksandrov, A Y; Ivanova, V Y

    2015-01-01

    Unconscious perception essentially affects human behavior. The main results in this area obtained in experiments with visual stimuli. However, the acoustical stimuli play not less important role in behavior. The main idea of this paper is the electroencephalographic investigation of unconscious acoustical stimulation effects on electro-physiological activity of the brain. For this purpose, the event-related potentials were acquired under unconscious stimulus priming paradigm. The one syllable, three letter length, Russian words and pseudo-words with single letter substitution were used as primes and targets. As a result, we find out that repetition and alternative priming similarly affects the event-related potential's component with 200 ms latency after target application in frontal parietal and temporal areas. Under alternative priming the direction of potential amplitude modification nearby 400 ms was altered for word and semi-word targets. Alternative priming reliably increase ERP's amplitude in 400 ms locality with pseudo-word targets and decrease it under word targets. Taking into account, that all participants were unable to distinguish the applied prime stimuli, we can assume that the event-related potential changes evoked by unconscious perception of acoustical stimuli. The ERP amplitude dynamics revealed in current investigation demonstrate the opportunity of subliminal acoustical stimuli to modulate the electrical activity evoked by verbal acoustical stimulation. PMID:26237945

  19. Device and method for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian; Nihei, Kurt T.; Schmitt, Denis P.; Skelt, Chirstopher

    2013-10-15

    In some aspects of the invention, a method of generating a beam of acoustic energy in a borehole is disclosed. The method includes generating a first acoustic wave at a first frequency; generating a second acoustic wave at a second frequency different than the first frequency, wherein the first acoustic wave and second acoustic wave are generated by at least one transducer carried by a tool located within the borehole; transmitting the first and the second acoustic waves into an acoustically non-linear medium, wherein the composition of the non-linear medium produces a collimated beam by a non-linear mixing of the first and second acoustic waves, wherein the collimated beam has a frequency based upon a difference between the first frequency range and the second frequency, and wherein the non-linear medium has a velocity of sound between 100 m/s and 800 m/s.

  20. Search for acoustic signals from high energy cascades

    NASA Technical Reports Server (NTRS)

    Bell, R.; Bowen, T.

    1985-01-01

    High energy cosmic ray secondaries can be detected by means of the cascades they produce when they pass through matter. When the charged particles of these cascades ionize the matter they are traveling through, the heat produced and resulting thermal expansion causes a thermoacoustic wave. These sound waves travel at about one hundred-thousandth the speed of light, and should allow an array of acoustic transducers to resolve structure in the cascade to about 1 cm without high speed electronics or segmentation of the detector.

  1. Helmholtz Resonator for Lead Zirconate Titanate Acoustic Energy Harvester

    NASA Astrophysics Data System (ADS)

    Matsuda, Tomohiro; Tomii, Kazuki; Hagiwara, Saori; Miyake, Shuntaro; Hasegawa, Yuichi; Sato, Takamitsu; Kaneko, Yuta; Nishioka, Yasushiro

    2013-12-01

    Acoustic energy harvesters that function in environments where sound pressure is extremely high (~150 dB), such as in engine rooms of aircrafts, are expected to be capable of powering wireless health monitoring systems. This paper presents the power generation performances of a lead-zirconate-titanate (PZT) acoustic energy harvester with a vibrating PZT diaphragm. The diaphragm had a diameter of 2 mm, consisting of Al(0.1 μm)/PZT(1 μm)/Pt(0.1 μm)/Ti(0.1 μm)/SiO2(1.5 μm). The harvester generated a power of 1.7×10-13 W under a sound pressure level of 110 dB at the first resonance frequency of 6.28 kHz. It was found that the generated power was increased to 6.8×10-13 W using a sound-collecting Helmholtz resonator cone with the height of 60 mm. The cone provided a Helmholtz resonance at 5.8 kHz, and the generated power increased from 3.4×10-14 W to 1.4×10-13 W at this frequency. The cone was also effective in increasing the bandwidth of the energy harvester.

  2. [Changes in early auditory evoked potentials in acoustic neuroma].

    PubMed

    Hoth, S

    1991-09-01

    The auditory brain-stem responses (ABRs) of 38 patients with acoustic neuroma (AN) were recorded pre-operatively and evaluated with regard to pathological deviations from the normal. Several qualitative and quantitative features of the ABRs were compared statistically with the results obtained from a control group for age and sex, and considering patients with various cochlear pathologies (Meniere's disease, sudden deafness, presbycusis). Retrocochlear disorders were ruled out by computed tomography or magnetic resonance imaging. Statistical analysis yielded the following results. The central conduction time (latency difference between Jewett waves J1 and J5) is significantly prolonged in the AN group. A critical value of 4.3 ms separates the retrocochlear from the cochlear lesions, with a sensitivity and specificity of 90%. If conductive hearing loss can be excluded, and if the amount of cochlear hearing loss is taken into account, about the same separation effectively is achieved by evaluation of the sole latency of J5 and its stimulus level dependence. The interaural difference of the central conduction time can be a useful parameter for indicating the presence of acoustic tumours, unless both sides are affected. The same is true of the interaural differences for the J5 latency, but this quantity must be corrected for the effects of peripheral hearing loss. The critical interaural difference values are 0.3 ms for the conduction time (at any stimulus level) and 0.5 ms for the latency of J5 (for stimulus levels above 60 dB nHL). A weaker distinction is provided by the amplitude of J5 and the amplitude ratio of J5 and J1. These quantities are only slightly smaller in cases of AN. Only the combination of small J5 amplitudes with large latency values can be regarded as being characteristic of retrocochlear lesions. This can be highlighted in an amplitude-latency diagram. Further hints as to the site of the lesion can be obtained from a distorted waveform morphology

  3. Acoustic tests of a 15.2 centimeter-diameter potential flow convergent nozzle

    NASA Technical Reports Server (NTRS)

    Karchmer, A. M.; Dorsch, R. G.; Friedman, R.

    1974-01-01

    An experimental investigation of the jet noise radiated to the far field from a 15.2-cm-diam potential flow convergent nozzle has been conducted. Tests were made with unheated airflow over a range of subsonic nozzle exhaust velocities from 62 to 310m/sec. Mean and turbulent velocity measurements in the flow field of the nozzle exhaust indicated no apparent flow anomalies. Acoustic measurements yielded data uncontaminated by internal and/or background noise to velocities as low as 152m/sec. Finally, no significantly different acoustic characteristics between the potential flow nozzle and simple convergent nozzles were found.

  4. A wideband acoustic energy harvester using a three degree-of-freedom architecture

    NASA Astrophysics Data System (ADS)

    Peng, Xiao; Wen, Yumei; Li, Ping; Yang, Aichao; Bai, Xiaoling

    2013-10-01

    In this study, an acoustic energy harvester consisting of a perforated brass plate sandwiched between two cavities is designed and fabricated for scavenging energy from wide-spectrum acoustic sources. The multi-mode resonances of the device are adjusted closely spaced over a wide range of frequencies by properly tuned acoustic coupling of the vibrating plate and the two cavities. The experimental results show that the proximity of the multiple peaks enables the harvester operating in the frequency range of 1100-1400 Hz, which provides useful leads for the realization of acoustic energy generators of practical interest.

  5. Generalization and extension of the law of acoustic energy conservation in a nonuniform flow

    NASA Technical Reports Server (NTRS)

    Myers, M. K.

    1986-01-01

    An exact conservation equation is derived which generalizes the familiar acoustic energy equations. The new relation is valid for arbitrary disturbances to a viscous, compressible flow. It is suggested by a development of the acoustic energy equation by means of a regular perturbation expansion of the general energy equation of fluid mechanics. A perturbation energy density and flux are defined and identified as the exact physical quantities whose leading order perturbation representations are the usual acoustic energy density and flux. The conservation equation governing the perturbation energy quantities is shown to yield previously known results for several special cases.

  6. Broadband energy harvesting using acoustic black hole structural tailoring

    NASA Astrophysics Data System (ADS)

    Zhao, Liuxian; Conlon, Stephen C.; Semperlotti, Fabio

    2014-06-01

    This paper explores the concept of an acoustic black hole (ABH) as a main design framework for performing dynamic structural tailoring of mechanical systems for vibration energy harvesting applications. The ABH is an integral feature embedded in the host structure that allows for a smooth reduction of the phase velocity, theoretically approaching zero, while minimizing the reflected energy. This mechanism results in structural areas with high energy density that can be effectively exploited to develop enhanced vibration-based energy harvesting. Fully coupled electro-mechanical models of an ABH tapered structure with surface mounted piezo-transducers are developed to numerically simulate the response of the system to both steady state and transient excitations. The design performances are numerically evaluated using structural intensity data as well as the instantaneous voltage/power and energy output produced by the piezo-transducer network. Results show that the dynamically tailored structural design enables a drastic increase in the harvested energy as compared to traditional structures, both under steady state and transient excitation conditions.

  7. Acoustic energy relations in Mudejar-Gothic churches.

    PubMed

    Zamarreño, Teófilo; Girón, Sara; Galindo, Miguel

    2007-01-01

    Extensive objective energy-based parameters have been measured in 12 Mudejar-Gothic churches in the south of Spain. Measurements took place in unoccupied churches according to the ISO-3382 standard. Monoaural objective measures in the 125-4000 Hz frequency range and in their spatial distributions were obtained. Acoustic parameters: clarity C80, definition D50, sound strength G and center time Ts have been deduced using impulse response analysis through a maximum length sequence measurement system in each church. These parameters spectrally averaged according to the most extended criteria in auditoria in order to consider acoustic quality were studied as a function of source-receiver distance. The experimental results were compared with predictions given by classical and other existing theoretical models proposed for concert halls and churches. An analytical semi-empirical model based on the measured values of the C80 parameter is proposed in this work for these spaces. The good agreement between predicted values and experimental data for definition, sound strength, and center time in the churches analyzed shows that the model can be used for design predictions and other purposes with reasonable accuracy. PMID:17297779

  8. Hypersingular meshless method using double-layer potentials for three-dimensional exterior acoustic problems.

    PubMed

    Young, D L; Chen, K H; Liu, T Y; Wu, C S

    2016-01-01

    Three-dimensional exterior acoustic problems with irregular domains are solved using a hypersingular meshless method. In particular, the method of fundamental solutions (MFS) is used to formulate and analyze such acoustic problems. It is well known that source points for MFS cannot be located on the real boundary due to the singularity of the kernel functions. Thus, the diagonal terms of the influence matrices are unobtainable when source points are located on the boundary. An efficient approach is proposed to overcome such difficulties, when the MFS is used for three-dimensional exterior acoustic problems. This work is an extension of previous research on two-dimensional problems. The solution of the problem is expressed in terms of a double-layer potential representation on the physical boundary. Three examples are presented in which the proposed method is compared to the MFS and boundary element method. Good numerical performance is demonstrated by the proposed hypersingular meshless method. PMID:26827046

  9. Renewable energy potential in Colombia

    NASA Astrophysics Data System (ADS)

    Correa Guzman, Jose Luis

    2008-12-01

    Renewable energy flows are very large in comparison with humankind's use of energy. In principle, all our energy needs, both now and into the future, can be met by energy from renewable sources. After many years trying to develop the alternative energy potential of Colombia, a major effort is principally being made since 2000 to explore and assess the renewable resources of the entire country. Until 2000, the availability of conventional energy sources in Colombia prevented renewable energy exploration from reaching a higher level. However, the extreme energy crisis of 1992 - 1993 alerted the authorities and the community to the necessity for exploring alternative energy sources. This energy study is a general approach to the current and future renewable energy scenario of Colombia. It was prepared in response to the increased interest around the world and in particular in Colombia to develop its non-fossil energy prospective. It, therefore, represents a working document giving an initial impression of the possible scale of the main renewables sources as a response to the concern about energy security and fossil fuel dependence problems. The assumptions made and calculations reported may therefore be subject to revision as more information becomes available. The aim of this dissertation is not only to improve the public understanding and discussion of renewable energy matters in Colombia but also to stimulate the development and application of renewable energy, wherever they have prospects of economic viability and environmental acceptability. To achieve such goal this paper reviews several renewable technologies, their availability, contribution and feasibility in Colombia.

  10. 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.

  11. A short latency vestibular evoked potential (VsEP) produced by bone-conducted acoustic stimulation

    NASA Astrophysics Data System (ADS)

    McAngus Todd, Neil P.; Rosengren, Sally M.; Colebatch, James G.

    2003-12-01

    In this paper data are presented from an experiment which provides evidence for the existence of a short latency, acoustically evoked potential of probable vestibular origin. The experiment was conducted in two phases using bone-conducted acoustic stimulation. In the first phase subjects were stimulated with 6-ms, 500-Hz tone bursts in order to obtain the threshold VT for vestibular evoked myogenic potentials (VEMP). It was confirmed that the difference between bone-conducted auditory and acoustic vestibular thresholds was slightly over 30 dB. The estimated threshold was then used as a reference value in the second part of the experiment to stimulate subjects over a range of intensities from -6 to +18 dB (re:VT). Averaged EEG recordings were made with eight Ag/AgCl electrodes placed on the scalp at Fpz, F3, F4, F7, F8, Cz, T3, and T4 according to the 10-20 system. Below VT auditory midlatency responses (MLRs) were observed. Above VT two additional potentials appeared: a positivity at about 10 ms (P10) which was maximal at Cz, and a negativity at about 15 ms (N15) which was maximal at Fpz. Extrapolation of the growth functions for the P10 and N15 indicated a threshold close to VT, consistent with a vestibular origin of these potentials. Given the low threshold of vestibular acoustic sensitivity it is possible that this mode may make a contribution to the detection of and affective responses to loud low frequency sounds. The evoked potentials may also have application as a noninvasive and nontraumatic test of vestibular projections to the cortex.

  12. California Industrial Energy Efficiency Potential

    SciTech Connect

    Coito, Fred; Worrell, Ernst; Price, Lynn; Masanet, Eric; RafaelFriedmann; Rufo, Mike

    2005-06-01

    This paper presents an overview of the modeling approach andhighlights key findings of a California industrial energy efficiencypotential study. In addition to providing estimates of technical andeconomic potential, the study examines achievable program potential undervarious program-funding scenarios. The focus is on electricity andnatural gas savings for manufacturing in the service territories ofCalifornia's investor-owned utilities (IOUs). The assessment is conductedby industry type and by end use. Both crosscutting technologies andindustry-specific process measures are examined. Measure penetration intothe marketplace is modeled as a function of customer awareness, measurecost effectiveness, and perceived market barriers. Data for the studycomes from a variety of sources, including: utility billing records, theEnergy Information Association (EIA) Manufacturing Energy ConsumptionSurvey (MECS), state-sponsored avoided cost studies, energy efficiencyprogram filings, and technology savings and cost data developed throughLawrence Berkeley National Laboratory (LBNL). The study identifies 1,706GWh and 47 Mth (million therms) per year of achievable potential over thenext twelve years under recent levels of program expenditures, accountingfor 5.2 percent of industrial electricity consumption and 1.3 percent ofindustrial natural gas consumption. These estimates grow to 2,748 GWh and192 Mth per year if all cost-effective and achievable opportunities arepursued. Key industrial electricity end uses, in terms of energy savingspotential, include compressed air and pumping systems that combine toaccount for about half of the total achievable potential estimates. Fornatural gas, savings are concentrated in the boiler and process heatingend uses, accounting for over 99 percent to total achievablepotential.

  13. A Correlated Study of the Response of a Satellite to Acoustic Radiation Using Statistical Energy Analysis and Acoustic Test Data

    SciTech Connect

    CAP,JEROME S.; TRACEY,BRIAN

    1999-11-15

    Aerospace payloads, such as satellites, are subjected to vibroacoustic excitation during launch. Sandia's MTI satellite has recently been certified to this environment using a combination of base input random vibration and reverberant acoustic noise. The initial choices for the acoustic and random vibration test specifications were obtained from the launch vehicle Interface Control Document (ICD). In order to tailor the random vibration levels for the laboratory certification testing, it was necessary to determine whether vibration energy was flowing across the launch vehicle interface from the satellite to the launch vehicle or the other direction. For frequencies below 120 Hz this issue was addressed using response limiting techniques based on results from the Coupled Loads Analysis (CLA). However, since the CLA Finite Element Analysis FEA model was only correlated for frequencies below 120 Hz, Statistical Energy Analysis (SEA) was considered to be a better choice for predicting the direction of the energy flow for frequencies above 120 Hz. The existing SEA model of the launch vehicle had been developed using the VibroAcoustic Payload Environment Prediction System (VAPEPS) computer code [1]. Therefore, the satellite would have to be modeled using VAPEPS as well. As is the case for any computational model, the confidence in its predictive capability increases if one can correlate a sample prediction against experimental data. Fortunately, Sandia had the ideal data set for correlating an SEA model of the MTI satellite--the measured response of a realistic assembly to a reverberant acoustic test that was performed during MTI's qualification test series. The first part of this paper will briefly describe the VAPEPS modeling effort and present the results of the correlation study for the VAPEPS model. The second part of this paper will present the results from a study that used a commercial SEA software package [2] to study the effects of in-plane modes and to

  14. The potential of renewable energy

    SciTech Connect

    Not Available

    1990-03-01

    On June 27 and 28, 1989, the US Department of Energy (DOE) national laboratories were convened to discuss plans for the development of a National Energy Strategy (NES) and, in particular, the analytic needs in support of NES that could be addressed by the laboratories. As a result of that meeting, interlaboratory teams were formed to produce analytic white papers on key topics, and a lead laboratory was designated for each core laboratory team. The broad-ranging renewables assignment is summarized by the following issue statement from the Office of Policy, Planning and Analysis: to what extent can renewable energy technologies contribute to diversifying sources of energy supply What are the major barriers to greater renewable energy use and what is the potential timing of widespread commercialization for various categories of applications This report presents the results of the intensive activity initiated by the June 1989 meeting to produce a white paper on renewable energy. Scores of scientists, analysts, and engineers in the five core laboratories gave generously of their time over the past eight months to produce this document. Their generous, constructive efforts are hereby gratefully acknowledged. 126 refs., 44 figs., 32 tabs.

  15. Energy analysis during acoustic bubble oscillations: relationship between bubble energy and sonochemical parameters.

    PubMed

    Merouani, Slimane; Hamdaoui, Oualid; Rezgui, Yacine; Guemini, Miloud

    2014-01-01

    In this work, energy analysis of an oscillating isolated spherical bubble in water irradiated by an ultrasonic wave has been theoretically studied for various conditions of acoustic amplitude, ultrasound frequency, static pressure and liquid temperature in order to explain the effects of these key parameters on both sonochemistry and sonoluminescence. The Keller-Miksis equation for the temporal variation of the bubble radius in compressible and viscous medium has been employed as a dynamics model. The numerical calculations showed that the rate of energy accumulation, dE/dt, increased linearly with increasing acoustic amplitude in the range of 1.5-3.0 atm and decreased sharply with increasing frequency in the range 200-1000 kHz. There exists an optimal static pressure at which the power w is highest. This optimum shifts toward a higher value as the acoustic amplitude increases. The energy of the bubble slightly increases with the increase in liquid temperature from 10 to 60 °C. The results of this study should be a helpful means to explain a variety of experimental observations conducted in the field of sonochemistry and sonoluminescence concerning the effects of operational parameters. PMID:23683796

  16. Effect of static pressure on acoustic energy radiated by cavitation bubbles in viscous liquids under ultrasound.

    PubMed

    Yasui, Kyuichi; Towata, Atsuya; Tuziuti, Toru; Kozuka, Teruyuki; Kato, Kazumi

    2011-11-01

    The effect of static pressure on acoustic emissions including shock-wave emissions from cavitation bubbles in viscous liquids under ultrasound has been studied by numerical simulations in order to investigate the effect of static pressure on dispersion of nano-particles in liquids by ultrasound. The results of the numerical simulations for bubbles of 5 μm in equilibrium radius at 20 kHz have indicated that the optimal static pressure which maximizes the energy of acoustic waves radiated by a bubble per acoustic cycle increases as the acoustic pressure amplitude increases or the viscosity of the solution decreases. It qualitatively agrees with the experimental results by Sauter et al. [Ultrason. Sonochem. 15, 517 (2008)]. In liquids with relatively high viscosity (∼200 mPa s), a bubble collapses more violently than in pure water when the acoustic pressure amplitude is relatively large (∼20 bar). In a mixture of bubbles of different equilibrium radius (3 and 5 μm), the acoustic energy radiated by a 5 μm bubble is much larger than that by a 3 μm bubble due to the interaction with bubbles of different equilibrium radius. The acoustic energy radiated by a 5 μm bubble is substantially increased by the interaction with 3 μm bubbles. PMID:22087995

  17. Applications of velocity potential function to acoustic duct propagation and radiation from inlets using finite element theory

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.; Majjigi, R. K.

    1979-01-01

    A finite element velocity potential program was developed to study acoustic wave propagation in complex geometries. For irrotational flows, relatively low sound frequencies, and plane wave input, the finite element solutions showed significant effects of inlet curvature and flow gradients on the attenuation of a given acoustic liner in a realistic variable area turbofan inlet. The velocity potential approach can not be used to estimate the effects of rotational flow on acoustic propagation, since the potential acoustic disturbances propagate at the speed of the media in sheared flow. Approaches are discussed that are being considered for extending the finite element solution to include the far field, as well as the internal portion of the duct. A new matrix partitioning approach is presented that can be incorporated in previously developed programs to allow the finite element calculation to be marched into the far field. The partitioning approach provided a large reduction in computer storage and running times.

  18. Device and method for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N; Pantea, Cristian; Nihei, Kurt T; Schmitt, Denis P; Skelt, Christopher

    2013-10-01

    In some aspects of the invention, a method of generating a beam of acoustic energy in a borehole is disclosed. The method includes generating a first broad-band acoustic pulse at a first broad-band frequency range having a first central frequency and a first bandwidth spread; generating a second broad-band acoustic pulse at a second broad-band frequency range different than the first frequency range having a second central frequency and a second bandwidth spread, wherein the first acoustic pulse and second acoustic pulse are generated by at least one transducer arranged on a tool located within the borehole; and transmitting the first and the second broad-band acoustic pulses into an acoustically non-linear medium, wherein the composition of the non-linear medium produces a collimated pulse by a non-linear mixing of the first and second acoustic pulses, wherein the collimated pulse has a frequency equal to the difference in frequencies between the first central frequency and the second central frequency and a bandwidth spread equal to the sum of the first bandwidth spread and the second bandwidth spread.

  19. Event-related potentials demonstrate deficits in acoustic segmentation in schizophrenia.

    PubMed

    Coffman, Brian A; Haigh, Sarah M; Murphy, Tim K; Salisbury, Dean F

    2016-05-01

    Segmentation of the acoustic environment into discrete percepts is an important facet of auditory scene analysis (ASA). Segmentation of auditory stimuli into perceptually meaningful and localizable groups is central to ASA in everyday situations; for example, separation of discrete words from continuous sentences when processing language. This is particularly relevant to schizophrenia, where deficits in perceptual organization have been linked to symptoms and cognitive dysfunction. Here we examined event-related potentials in response to grouped tones to elucidate schizophrenia-related differences in acoustic segmentation. We report for the first time in healthy subjects a sustained potential that begins with group initiation and ends with the last tone of the group. These potentials were reduced in schizophrenia, with the greatest differences in responses to first and final tones. Importantly, reductions in sustained potentials in schizophrenia patients were associated with greater negative symptoms and deficits in IQ, working memory, learning, and social cognition. These results suggest deficits in auditory pattern segmentation in schizophrenia may compound deficits in many higher-order facets of the disorder. PMID:27032476

  20. An analysis of the acoustic energy in a flow duct with a vortex sheet

    NASA Astrophysics Data System (ADS)

    Boij, Susann

    2009-03-01

    Modelling the acoustic scattering and absorption at an area expansion in a flow duct requires the incorporation of the flow-acoustic interaction. One way to quantify the interaction is to study the energy in the incident and the scattered field respectively. If the interaction is strong, energy may be transferred between the acoustic and the main flow field. In particular, shear layers, that may be the result of the flow separation, are unstable to low frequency perturbations such as acoustic waves. The vortex sheet model is an analytical linear acoustic model, developed to study scattering of acoustic waves in duct with sharp edges including the interaction with primarily the separated flows that arise at sharp edges and corners. In the model the flow field at an area expansion in a duct is described as a jet issuing into the larger part of the duct. In this paper, the flow-acoustic interaction is described in terms of energy flow. The linear convective wave equation is solved for a two-dimensional, rectangular flow duct geometry. The resulting modes are classified as "hydrodynamic" and "acoustic" when separating the acoustic energy from the part of the energy arising from the steady flow field. In the downstream duct, the set of modes for this complex flow field are not orthogonal. For small Strouhal numbers, the plane wave and the two hydrodynamic waves are all plane, although propagating with different wave speeds. As the Strouhal numbers increases, the hydrodynamic modes changes to get a shape where the amplitude is concentrated near the vortex sheet. In an intermediate Strouhal number region, the mode shape of the first higher order mode is very similar to the damped hydrodynamic mode. A physical interpretation of this is that we have a strong coupling between the flow field and the acoustic field when the modes are non-orthogonal. Energy concepts for this duct configuration and mean flow profile are introduced. The energy is formulated such that the vortex

  1. Separating acoustic deviance from novelty during the first year of life: a review of event-related potential evidence

    PubMed Central

    Kushnerenko, Elena V.; Van den Bergh, Bea R. H.; Winkler, István

    2013-01-01

    Orienting to salient events in the environment is a first step in the development of attention in young infants. Electrophysiological studies have indicated that in newborns and young infants, sounds with widely distributed spectral energy, such as noise and various environmental sounds, as well as sounds widely deviating from their context elicit an event-related potential (ERP) similar to the adult P3a response. We discuss how the maturation of event-related potentials parallels the process of the development of passive auditory attention during the first year of life. Behavioral studies have indicated that the neonatal orientation to high-energy stimuli gradually changes to attending to genuine novelty and other significant events by approximately 9 months of age. In accordance with these changes, in newborns, the ERP response to large acoustic deviance is dramatically larger than that to small and moderate deviations. This ERP difference, however, rapidly decreases within first months of life and the differentiation of the ERP response to genuine novelty from that to spectrally rich but repeatedly presented sounds commences during the same period. The relative decrease of the response amplitudes elicited by high-energy stimuli may reflect development of an inhibitory brain network suppressing the processing of uninformative stimuli. Based on data obtained from healthy full-term and pre-term infants as well as from infants at risk for various developmental problems, we suggest that the electrophysiological indices of the processing of acoustic and contextual deviance may be indicative of the functioning of auditory attention, a crucial prerequisite of learning and language development. PMID:24046757

  2. On the relationship between acoustic energy density flux near the jet axis and far field acoustic intensity

    NASA Technical Reports Server (NTRS)

    Maestrello, L.

    1973-01-01

    By measurement and analysis, the relationship between the distribution of the outflow of acoustic energy over the jet boundary and the far-field intensity is considered. The physical quantity used is the gradient of the pressure evaluated on a geometrical plane at the smallest possible radial distance from the jet axis, but outside the vortical region, in the area where the homogeneous wave equation is reasonably well satisfied. The numerical and experimental procedures involved have been checked out by using a known source. Results indicate that the acoustic power output per unit length of the jet, in the region from which the sound emanates, peaks at approximately 9 diameters downstream. The acoustic emission for a jet Strouhal number of about 0.3 exceeds the emission for all other Strouhal numbers nearly everywhere along the measurement plane. However, the far-field peak intensity distribution obtained from the contribution of each station was found to depend on the spatial extent of the region where sound emanates from the jet, which, in turn, depends more on the far-field angle than on the Strouhal number.

  3. Transmission of wave energy in curved ducts. [acoustic propagation within rigid walls

    NASA Technical Reports Server (NTRS)

    Rostafinski, W.

    1974-01-01

    Investigation of the ability of circular bends to transmit acoustic energy flux. A formulation of wave-energy flow is developed for motion in curved ducts. A parametric study over a range of frequencies shows the ability of circular bends to transmit energy in the case of perfectly rigid walls.

  4. Dynamical energy analysis for built-up acoustic systems at high frequencies.

    PubMed

    Chappell, D J; Giani, S; Tanner, G

    2011-09-01

    Standard methods for describing the intensity distribution of mechanical and acoustic wave fields in the high frequency asymptotic limit are often based on flow transport equations. Common techniques are statistical energy analysis, employed mostly in the context of vibro-acoustics, and ray tracing, a popular tool in architectural acoustics. Dynamical energy analysis makes it possible to interpolate between standard statistical energy analysis and full ray tracing, containing both of these methods as limiting cases. In this work a version of dynamical energy analysis based on a Chebyshev basis expansion of the Perron-Frobenius operator governing the ray dynamics is introduced. It is shown that the technique can efficiently deal with multi-component systems overcoming typical geometrical limitations present in statistical energy analysis. Results are compared with state-of-the-art hp-adaptive discontinuous Galerkin finite element simulations. PMID:21895083

  5. 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.

  6. The potential influence of morphology on the evolutionary divergence of an acoustic signal

    PubMed Central

    Pitchers, W. R.; Klingenberg, C.P.; Tregenza, Tom; Hunt, J.; Dworkin, I.

    2014-01-01

    The evolution of acoustic behaviour and that of the morphological traits mediating its production are often coupled. Lack of variation in the underlying morphology of signalling traits has the potential to constrain signal evolution. This relationship is particularly likely in field crickets, where males produce acoustic advertisement signals to attract females by stridulating with specialized structures on their forewings. In this study, we characterise the size and geometric shape of the forewings of males from six allopatric populations of the black field cricket (Teleogryllus commodus) known to have divergent advertisement calls. We sample from each of these populations using both wild-caught and common-garden reared cohorts, allowing us to test for multivariate relationships between wing morphology and call structure. We show that the allometry of shape has diverged across populations. However, there was a surprisingly small amount of covariation between wing shape and call structure within populations. Given the importance of male size for sexual selection in crickets, the divergence we observe among populations has the potential to influence the evolution of advertisement calls in this species. PMID:25223712

  7. The potential influence of morphology on the evolutionary divergence of an acoustic signal.

    PubMed

    Pitchers, W R; Klingenberg, C P; Tregenza, T; Hunt, J; Dworkin, I

    2014-10-01

    The evolution of acoustic behaviour and that of the morphological traits mediating its production are often coupled. Lack of variation in the underlying morphology of signalling traits has the potential to constrain signal evolution. This relationship is particularly likely in field crickets, where males produce acoustic advertisement signals to attract females by stridulating with specialized structures on their forewings. In this study, we characterize the size and geometric shape of the forewings of males from six allopatric populations of the black field cricket (Teleogryllus commodus) known to have divergent advertisement calls. We sample from each of these populations using both wild-caught and common-garden-reared cohorts, allowing us to test for multivariate relationships between wing morphology and call structure. We show that the allometry of shape has diverged across populations. However, there was a surprisingly small amount of covariation between wing shape and call structure within populations. Given the importance of male size for sexual selection in crickets, the divergence we observe among populations has the potential to influence the evolution of advertisement calls in this species. PMID:25223712

  8. [Physiological-occupational assessment of acoustic load with equal energy but different time and informational characteristics].

    PubMed

    Suvorov, G A; Shkarinov, L N; Kravchenko, O K; Kur'erov, N N

    1999-01-01

    The article deals with results of experimental study comparing effects of 4 types of acoustic load--noise (constant and impulse) and music (electronic symphonic one and rap)--on hearing sensitivity, processes in nervous system and subjective evaluation. All types of acoustic load were equal in energy (on evaluation according to equivalent level during the experiment). The study included 2 levels of load--90 and 95 dB. The differences revealed demonstrate importance of impulse parameters of noise and musical load for reactions of acoustic analyzer and central nervous system. The experiments show that evaluation of harm caused by temporary and impulse noises should be based not only on assessment of specific (hearing) function, but also on parameters of central nervous system state. The authors found that music of certain acoustic and informational parameters may harm hearing function. PMID:10420710

  9. Reverberant acoustic energy in auditoria that comprise systems of coupled rooms

    NASA Astrophysics Data System (ADS)

    Summers, Jason E.

    2003-11-01

    A frequency-dependent model for reverberant energy in coupled rooms is developed and compared with measurements for a 1:10 scale model and for Bass Hall, Ft. Worth, TX. At high frequencies, prior statistical-acoustics models are improved by geometrical-acoustics corrections for decay within sub-rooms and for energy transfer between sub-rooms. Comparisons of computational geometrical acoustics predictions based on beam-axis tracing with scale model measurements indicate errors resulting from tail-correction assuming constant quadratic growth of reflection density. Using ray tracing in the late part corrects this error. For mid-frequencies, the models are modified to account for wave effects at coupling apertures by including power transmission coefficients. Similarly, statical-acoustics models are improved through more accurate estimates of power transmission measurements. Scale model measurements are in accord with the predicted behavior. The edge-diffraction model is adapted to study transmission through apertures. Multiple-order scattering is theoretically and experimentally shown inaccurate due to neglect of slope diffraction. At low frequencies, perturbation models qualitatively explain scale model measurements. Measurements confirm relation of coupling strength to unperturbed pressure distribution on coupling surfaces. Measurements in Bass Hall exhibit effects of the coupled stage house. High frequency predictions of statistical acoustics and geometrical acoustics models and predictions of coupling apertures all agree with measurements.

  10. Observations of potential acoustic cues that attract sperm whales to longline fishing in the Gulf of Alaska.

    PubMed

    Thode, Aaron; Straley, Janice; Tiemann, Christopher O; Folkert, Kendall; O'Connell, Victoria

    2007-08-01

    Sperm whales (Physeter macrocephalus) have learned to remove fish from demersal longline gear deployments off the eastern Gulf of Alaska, and are often observed to arrive at a site after a haul begins, suggesting a response to potential acoustic cues like fishing-gear strum, hydraulic winch tones, and propeller cavitation. Passive acoustic recorders attached to anchorlines have permitted continuous monitoring of the ambient noise environment before and during fishing hauls. Timing and tracking analyses of sperm whale acoustic activity during three encounters indicate that cavitation arising from changes in ship propeller speeds is associated with interruptions in nearby sperm whale dive cycles and changes in acoustically derived positions. This conclusion has been tested by cycling a vessel engine and noting the arrival of whales by the vessel, even when the vessel is not next to fishing gear. No evidence of response from activation of ship hydraulics or fishing gear strum has been found to date. PMID:17672672

  11. Seismic-acoustic energy partitioning during a paroxysmal eruptive phase of Tungurahua volcano, Ecuador

    NASA Astrophysics Data System (ADS)

    Palacios, Pablo B.; Díez, Mikel; Kendall, J.-Michael; Mader, Heidy M.

    2016-04-01

    Studies of discrete volcanic explosions, that usually last less than two or three minutes, have suggested that the partitioning of seismic-acoustic energy is likely related to a range of physical mechanisms that depend on magma properties and other physical constraints such as the location of the fragmentation surface. In this paper we explore the energy partition of a paroxysmal eruptive phase of Tungurahua volcano that lasted for over four hours, on 2006 July 14 - 15, using seismic-acoustic information recorded by stations on its flanks (near field). We find evidence of a linear scaling between seismic and acoustic energies, with time dependent intensities, during the sustained explosive phase of the eruption. Furthermore, we argue that this scaling can be explained by two different processes: (1) the fragmentation region ultimately acts as the common source of energy producing both direct seismic waves, that travel through the volcanic edifice, and direct acoustic waves coming from a disturbed atmosphere above the summit; (2) the coupling of acoustic waves with the ground to cause seismic waves. Both processes are concurrent, however we have found that the first one is dominant for seismic records below 4 Hz. Here we use the linear scaling of intensities to construct seismic and acoustic indices, which, we argue, could be used to track an ongoing eruption. Thus, especially in strong paroxysms that can produce pyroclastic flows, the index correlation and their levels can be used as quantitative monitoring parameters to assess the volcanic hazard in real time. Additionally, we suggest from the linear scaling that the source type for both cases, seismic and acoustic, is dipolar and dominant in the near field.

  12. Seismic-acoustic energy partitioning during a paroxysmal eruptive phase of Tungurahua volcano, Ecuador

    NASA Astrophysics Data System (ADS)

    Palacios, Pablo B.; Díez, Mikel; Kendall, J.-Michael; Mader, Heidy M.

    2016-06-01

    Studies of discrete volcanic explosions, that usually last less than 2 or 3 min, have suggested that the partitioning of seismic-acoustic energy is likely related to a range of physical mechanisms that depend on magma properties and other physical constraints such as the location of the fragmentation surface. In this paper, we explore the energy partition of a paroxysmal eruptive phase of Tungurahua volcano that lasted for over 4 hr, on 2006 July 14-15, using seismic-acoustic information recorded by stations on its flanks (near field). We find evidence of a linear scaling between seismic and acoustic energies, with time-dependent intensities, during the sustained explosive phase of the eruption. Furthermore, we argue that this scaling can be explained by two different processes: (1) the fragmentation region ultimately acts as the common source of energy producing both direct seismic waves, that travel through the volcanic edifice, and direct acoustic waves coming from a disturbed atmosphere above the summit; (2) the coupling of acoustic waves with the ground to cause seismic waves. Both processes are concurrent, however we have found that the first one is dominant for seismic records below 4 Hz. Here we use the linear scaling of intensities to construct seismic and acoustic indices, which, we argue, could be used to track an ongoing eruption. Thus, especially in strong paroxysms that can produce pyroclastic flows, the index correlation and their levels can be used as quantitative monitoring parameters to assess the volcanic hazard in real time. Additionally, we suggest from the linear scaling that the source type for both cases, seismic and acoustic, is dipolar and dominant in the near field.

  13. Ultrasound effects on miniature end plate potential discharge frequency are contingent upon acoustic environment.

    PubMed

    Revell, W J; Roberts, M G

    1990-05-01

    The effects of low level ultrasonic stimulation (250 mW cm-2; 1.5 MHz; continuous wave) on the frequency of miniature end-plate potential (MEPP) production, at the frog neuromuscular junction, have been examined in two situations. In a simple exposure environment, where the muscle was immersed in Ringer solution and stretched over a polyurethane resin base at room temperature, the ultrasound stimulus produced a marked increase in the MEPP discharge rate, with only a small concomitant rise (1.0-1.6 degrees C) in local temperature. Control temperature increases of a similar magnitude produced only small changes in the rate of MEPP production. The experiment was repeated in an environment with better defined field conditions. The muscle was suspended in a chamber sealed at the base with an acoustically transparent polycarbonate material, 0.05 mm thick, and contained in a thermostatically controlled bath lined with an acoustically absorbent material. In this situation, no increase in MEPP frequency was observed in response to ultrasonication, although the local measured temperature increase was similar in both magnitude and time course. It is suggested that these results may depend upon differences between standing wave conditions and free field progression of the beam through the sample. PMID:2339472

  14. Unlocking the Potential of High-Throughput Drug Combination Assays Using Acoustic Dispensing.

    PubMed

    Chan, Grace Ka Yan; Wilson, Stacy; Schmidt, Stephen; Moffat, John G

    2016-02-01

    Assessment of synergistic effects of drug combinations in vitro is a critical part of anticancer drug research. However, the complexities of dosing and analyzing two drugs over the appropriate range of doses have generally led to compromises in experimental design that restrict the quality and robustness of the data. In particular, the use of a single dose response of combined drugs, rather than a full two-way matrix of varying doses, has predominated in higher-throughput studies. Acoustic dispensing unlocks the potential of high-throughput dose matrix analysis. We have developed acoustic dispensing protocols that enable compound synergy assays in a 384-well format. This experimental design is considerably more efficient and flexible with respect to time, reagent usage, and labware than is achievable using traditional serial-dilution approaches. Data analysis tools integrated in Genedata Screener were used to efficiently deconvolute the combination compound mapping scheme and calculate compound potency and synergy metrics. We have applied this workflow to evaluate interactions among drugs targeting different nodes of the mitogen-activated protein kinase pathway in a panel of cancer cell lines. PMID:26160862

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2016-01-01

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

  17. Theoretical Estimation of the Acoustic Energy Generation and Absorption Caused by Jet Oscillation

    NASA Astrophysics Data System (ADS)

    Takahashi, Kin'ya; Iwagami, Sho; Kobayashi, Taizo; Takami, Toshiya

    2016-04-01

    We investigate the energy transfer between the fluid field and acoustic field caused by a jet driven by an acoustic particle velocity field across it, which is the key to understanding the aerodynamic sound generation of flue instruments, such as the recorder, flute, and organ pipe. Howe's energy corollary allows us to estimate the energy transfer between these two fields. For simplicity, we consider the situation such that a free jet is driven by a uniform acoustic particle velocity field across it. We improve the semi-empirical model of the oscillating jet, i.e., exponentially growing jet model, which has been studied in the field of musical acoustics, and introduce a polynomially growing jet model so as to apply Howe's formula to it. It is found that the relative phase between the acoustic oscillation and jet oscillation, which changes with the distance from the flue exit, determines the quantity of the energy transfer between the two fields. The acoustic energy is mainly generated in the downstream area, but it is consumed in the upstream area near the flue exit in driving the jet. This theoretical examination well explains the numerical calculation of Howe's formula for the two-dimensional flue instrument model in our previous work [Fluid Dyn. Res. 46, 061411 (2014)] as well as the experimental result of Yoshikawa et al. [J. Sound Vib. 331, 2558 (2012)].

  18. Geothermal Energy: Tapping the Potential

    ERIC Educational Resources Information Center

    Johnson, Bill

    2008-01-01

    Ground source geothermal energy enables one to tap into the earth's stored renewable energy for heating and cooling facilities. Proper application of ground-source geothermal technology can have a dramatic impact on the efficiency and financial performance of building energy utilization (30%+). At the same time, using this alternative energy…

  19. Resource Evaluation and Energy Production Estimate for a Tidal Energy Conversion Installation using Acoustic Flow Measurements

    NASA Astrophysics Data System (ADS)

    Gagnon, Ian; Baldwin, Ken; Wosnik, Martin

    2015-11-01

    The ``Living Bridge'' project plans to install a tidal turbine at Memorial Bridge in the Piscataqua River at Portsmouth, NH. A spatio-temporal tidal energy resource assessment was performed using long term bottom-deployed Acoustic Doppler Current Profilers ADCP. Two locations were evaluated: at the planned deployment location and mid-channel. The goal was to determine the amount of available kinetic energy that can be converted into usable electrical energy on the bridge. Changes in available kinetic energy with ebb/flood and spring/neap tidal cycles and electrical energy demand were analyzed. A system model is used to calculate the net energy savings using various tidal generator and battery bank configurations. Differences in the tidal characteristics between the two measurement locations are highlighted. Different resource evaluation methodologies were also analyzed, e.g., using a representative ADCP ``bin'' vs. a more refined, turbine-geometry-specific methodology, and using static bin height vs. bin height that move w.r.t. the free surface throughout a tidal cycle (representative of a bottom-fixed or floating turbine deployment, respectively). ADCP operating frequencies and bin sizes affect the standard deviation of measurements, and measurement uncertainties are evaluated. Supported by NSF-IIP grant 1430260.

  20. An Energy Signature Scheme for Steam Trap Assessment and Flow Rate Estimation Using Pipe-Induced Acoustic Measurements

    SciTech Connect

    Olama, Mohammed M; Allgood, Glenn O; Kuruganti, Phani Teja; Lake, Joe E

    2012-01-01

    The US Congress has passed legislation dictating that all government agencies establish a plan and process for improving energy efficiencies at their sites. In response to this legislation, Oak Ridge National Laboratory (ORNL) has recently conducted a pilot study to explore the deployment of a wireless sensor system for a real-time measurement-based energy efficiency optimization framework within the steam distribution system within the ORNL campus. We make assessments on the real-time status of the distribution system by observing the state measurements of acoustic sensors mounted on the steam pipes/traps/valves. In this paper, we describe a spectral-based energy signature scheme that interprets acoustic vibration sensor data to estimate steam flow rates and assess steam traps health status. Experimental results show that the energy signature scheme has the potential to identify different steam trap health status and it has sufficient sensitivity to estimate steam flow rate. Moreover, results indicate a nearly quadratic relationship over the test region between the overall energy signature factor and flow rate in the pipe. The analysis based on estimated steam flow and steam trap status helps generate alerts that enable operators and maintenance personnel to take remedial action. The goal is to achieve significant energy-saving in steam lines by monitoring and acting on leaking steam pipes/traps/valves.

  1. An energy signature scheme for steam trap assessment and flow rate estimation using pipe-induced acoustic measurements

    NASA Astrophysics Data System (ADS)

    Olama, Mohammed M.; Allgood, Glenn O.; Kuruganti, Teja P.; Lake, Joe E.

    2012-06-01

    The US Congress has passed legislation dictating that all government agencies establish a plan and process for improving energy efficiencies at their sites. In response to this legislation, Oak Ridge National Laboratory (ORNL) has recently conducted a pilot study to explore the deployment of a wireless sensor system for a real-time measurement-based energy efficiency optimization framework within the steam distribution system within the ORNL campus. We make assessments on the real-time status of the distribution system by observing the state measurements of acoustic sensors mounted on the steam pipes/traps/valves. In this paper, we describe a spectral-based energy signature scheme that interprets acoustic vibration sensor data to estimate steam flow rates and assess steam traps health status. Experimental results show that the energy signature scheme has the potential to identify different steam trap health status and it has sufficient sensitivity to estimate steam flow rate. Moreover, results indicate a nearly quadratic relationship over the test region between the overall energy signature factor and flow rate in the pipe. The analysis based on estimated steam flow and steam trap status helps generate alerts that enable operators and maintenance personnel to take remedial action. The goal is to achieve significant energy-saving in steam lines by monitoring and acting on leaking steam pipes/traps/valves.

  2. Contributed Review: Recent developments in acoustic energy harvesting for autonomous wireless sensor nodes applications

    NASA Astrophysics Data System (ADS)

    Khan, Farid Ullah; Khattak, Muhammad Umair

    2016-02-01

    Rapid developments in micro electronics, micro fabrication, ultra-large scale of integration, ultra-low power sensors, and wireless technology have greatly reduced the power consumption requirements of wireless sensor nodes (WSNs) and make it possible to operate these devices with energy harvesters. Likewise, other energy harvesters, acoustic energy harvesters (AEHs), have been developed and are gaining swift interest in last few years. This paper presents a review of AEHs reported in the literature for the applications of WSNs. Based on transduction mechanism, there are two types of AEHs: piezoelectric acoustic energy harvesters (PEAEHs) and electromagnetic acoustic energy harvesters (EMAEHs). The reported AEHs are mostly characterized under the sound pressure level (SPL) that ranges from 45 to 161 dB. The range for resonant frequency of the produced AEHs is from 146 Hz to 24 kHz and these produced 0.68 × 10-6 μW to 30 mW power. The maximum power (30 mW) is produced by a PEAEH, when the harvester is subjected to a SPL of 161 dB and 2.64 kHz frequency. However, for EMAEHs, the maximum power reported is about 1.96 mW (at 125 dB and 143 Hz). Under the comparable SPLs, the power production by the reported EMAEHs is relatively better than that of PEAEHs, moreover, due to lower resonant frequency, the EMAEHs are more feasible for the low frequency band acoustical environment.

  3. Thermal Acoustic Sensor for High Pulse Energy X-ray FEL Beams

    SciTech Connect

    Smith, T.J.; Frisch, J.C.; Kraft, E.M.; Loos, J.; Bentsen, G.S.; /Rochester U.

    2011-12-13

    The pulse energy density of X-ray FELs will saturate or destroy conventional X-ray diagnostics, and the use of large beam attenuation will result in a beam that is dominated by harmonics. We present preliminary results at the LCLS from a pulse energy detector based on the thermal acoustic effect. In this type of detector an X-ray resistant material (boron carbide in this system) intercepts the beam. The pulse heating of the target material produces an acoustic pulse that can be detected with high frequency microphones to produce a signal that is linear in the absorbed energy. The thermal acoustic detector is designed to provide first- and second-order calorimetric measurement of X-ray FEL pulse energy. The first-order calorimetry is a direct temperature measurement of a target designed to absorb all or most of the FEL pulse power with minimal heat leak. The second-order measurement detects the vibration caused by the rapid thermoelastic expansion of the target material each time it absorbs a photon pulse. Both the temperature change and the amplitude of the acoustic signal are directly related to the photon pulse energy.

  4. Contributed Review: Recent developments in acoustic energy harvesting for autonomous wireless sensor nodes applications.

    PubMed

    Khan, Farid Ullah; Khattak, Muhammad Umair

    2016-02-01

    Rapid developments in micro electronics, micro fabrication, ultra-large scale of integration, ultra-low power sensors, and wireless technology have greatly reduced the power consumption requirements of wireless sensor nodes (WSNs) and make it possible to operate these devices with energy harvesters. Likewise, other energy harvesters, acoustic energy harvesters (AEHs), have been developed and are gaining swift interest in last few years. This paper presents a review of AEHs reported in the literature for the applications of WSNs. Based on transduction mechanism, there are two types of AEHs: piezoelectric acoustic energy harvesters (PEAEHs) and electromagnetic acoustic energy harvesters (EMAEHs). The reported AEHs are mostly characterized under the sound pressure level (SPL) that ranges from 45 to 161 dB. The range for resonant frequency of the produced AEHs is from 146 Hz to 24 kHz and these produced 0.68 × 10(-6) μW to 30 mW power. The maximum power (30 mW) is produced by a PEAEH, when the harvester is subjected to a SPL of 161 dB and 2.64 kHz frequency. However, for EMAEHs, the maximum power reported is about 1.96 mW (at 125 dB and 143 Hz). Under the comparable SPLs, the power production by the reported EMAEHs is relatively better than that of PEAEHs, moreover, due to lower resonant frequency, the EMAEHs are more feasible for the low frequency band acoustical environment. PMID:26931827

  5. Distinguishing interacting dark energy from wCDM with CMB, lensing, and baryon acoustic oscillation data

    NASA Astrophysics Data System (ADS)

    Väliviita, Jussi; Palmgren, Elina

    2015-07-01

    We employ the Planck 2013 CMB temperature anisotropy and lensing data, and baryon acoustic oscillation (BAO) data to constrain a phenomenological wCDM model, where dark matter and dark energy interact. We assume time-dependent equation of state parameter for dark energy, and treat dark matter and dark energy as fluids whose energy-exchange rate is proportional to the dark-matter density. The CMB data alone leave a strong degeneracy between the interaction rate and the physical CDM density parameter today, ωc, allowing a large interaction rate |Γ| ~ H0. However, as has been known for a while, the BAO data break this degeneracy. Moreover, we exploit the CMB lensing potential likelihood, which probes the matter perturbations at redshift z ~ 2 and is very sensitive to the growth of structure, and hence one of the tools for discerning between the ΛCDM model and its alternatives. However, we find that in the non-phantom models (wde>-1), the constraints remain unchanged by the inclusion of the lensing data and consistent with zero interaction, -0.14 < Γ/H0 < 0.02 at 95% CL. On the contrary, in the phantom models (wde<-1), energy transfer from dark energy to dark matter is moderately favoured over the non-interacting model; 0-0.57 < Γ/H0 < -0.1 at 95% CL with CMB+BAO, while addition of the lensing data shifts this to -0.46 < Γ/H0 < -0.01.

  6. Broadband Acoustic Environment at a Tidal Energy Site in Puget Sound

    SciTech Connect

    Xu, Jinshan; Deng, Zhiqun; Martinez, Jayson J.; Carlson, Thomas J.; Myers, Joshua R.; Weiland, Mark A.

    2012-04-04

    Admiralty Inlet has been selected as a potential tidal energy site. It is located near shipping lanes, is a highly variable acoustic environment, and is frequented by the endangered southern resident killer whale (SRKW). Resolving environmental impacts is the first step to receiving approval to deploy tidal turbines. Several monitoring technologies are being considered to determine the presence of SRKW near the turbines. Broadband noise level measurements are critical for determining design and operational specifications of these technologies. Acoustic environment data at the proposed site was acquired at different depths using a cabled vertical line array from three different cruises during high tidal period in February, May, and June 2011. The ambient noise level decreases approximately 25 dB re 1 μPa per octave from frequency ranges of 1 kHz to 70 kHz, and increases approximately 20 dB re 1 μPa per octave for the frequency from 70 kHz to 200 kHz. The difference of noise pressure levels in different months varies from 10 to 30 dB re 1 μPa for the frequency range below 70 kHz. Commercial shipping and ferry vessel traffic were found to be the most significant contributors to sound pressure levels for the frequency range from 100 Hz to 70 kHz, and the variation could be as high as 30 dB re 1 μPa. These noise level measurements provide the basic information for designing and evaluating both active and passive monitoring systems proposed for deploying and operating for tidal power generation alert system.

  7. Potential of renewable and alternative energy sources

    NASA Astrophysics Data System (ADS)

    Konovalov, V.; Pogharnitskaya, O.; Rostovshchikova, A.; Matveenko, I.

    2015-11-01

    The article deals with application potential of clean alternative renewable energy sources. By means of system analysis the forecast for consumption of electrical energy in Tomsk Oblast as well as main energy sources of existing energy system have been studied up to 2018. Engineering potential of renewable and alternative energy sources is evaluated. Besides, ranking in the order of their efficiency descending is performed. It is concluded that Tomsk Oblast has high potential of alternative and renewable energy sources, among which the most promising development perspective is implementation of gasification stations to save fuel consumed by diesel power stations as well as building wind-power plants.

  8. Potential energy of a dinuclear system

    SciTech Connect

    Adamyan, G.G.; Antonenko, N.V.; Jolos, R.V.; Ivanova, S.P.; Mel`nikova, O.I.

    1994-11-01

    An effective method for calculating the potential energy of a dinuclear system is proposed. Analytic expressions for calculating the nuclear part of the nucleus-nucleus potential in the double-folding form are obtained. A relationship between this potential and the proximity potential is found. Effects of deformation and mutual orientation of nuclei on the interaction potential are studied. It follows from a comparison of calculated potential energies with nuclear binding energies that excited states of some nuclei can be treated as dinuclear or trinuclear systems. 27 refs., 7 figs.

  9. Evaluating damage potential of cryogenic concrete using acoustic emission sensors and permeability testing

    NASA Astrophysics Data System (ADS)

    Kogbara, Reginald B.; Parsaei, Boback; Iyengar, Srinath R.; Grasley, Zachary C.; Masad, Eyad A.; Zollinger, Dan G.

    2014-04-01

    This study evaluates the damage potential of concrete of different mix designs subjected to cryogenic temperatures, using acoustic emission (AE) and permeability testing. The aim is to investigate design methodologies that might be employed to produce concrete that resists damage when cooled to cryogenic temperatures. Such concrete would be suitable for primary containment of liquefied natural gas (LNG) and could replace currently used 9% Ni steel, thereby leading to huge cost savings. In the experiments described, concrete cubes, 150 mm x 150 mm x 150 mm, were cast using four different mix designs. The four mixes employed siliceous river sand as fine aggregate. Moreover, limestone, sandstone, trap rock and lightweight aggregate were individually used as coarse aggregates in the mixes. The concrete samples were then cooled from room temperature (20°C) to cryogenic temperature (-165°C) in a temperature chamber. AE sensors were placed on the concrete cubes during the cryogenic freezing process. The damage potential was evaluated in terms of the growth of damage as determined from AE, as a function of temperature and concrete mixture design. The damage potential observed was validated with water permeability testing. Initial results demonstrate the effects of the coefficient of thermal expansion (CTE) of the aggregates on damage growth. Concrete damage (cracking) resistance generally decreased with increasing coarse aggregate CTE, and was in the order, limestone ≥ trap rock << lightweight aggregate ≥ sandstone. Work is in progress to fully understand thermal dilation and damage growth in concrete due to differential CTE of its components.

  10. Nonlinear effects of dark energy clustering beyond the acoustic scales

    SciTech Connect

    Anselmi, Stefano; Sefusatti, Emiliano E-mail: dlopez_n@ictp.it

    2014-07-01

    We extend the resummation method of Anselmi and Pietroni (2012) to compute the total density power spectrum in models of quintessence characterized by a vanishing speed of sound. For standard ΛCDM cosmologies, this resummation scheme allows predictions with an accuracy at the few percent level beyond the range of scales where acoustic oscillations are present, therefore comparable to other, common numerical tools. In addition, our theoretical approach indicates an approximate but valuable and simple relation between the power spectra for standard quintessence models and models where scalar field perturbations appear at all scales. This, in turn, provides an educated guess for the prediction of nonlinear growth in models with generic speed of sound, particularly valuable since no numerical results are yet available.

  11. Enhanced acoustoelectric coupling in acoustic energy harvester using dual Helmholtz resonators.

    PubMed

    Peng, Xiao; Wen, Yumei; Li, Ping; Yang, Aichao; Bai, Xiaoling

    2013-10-01

    In this paper, enhanced acoustoelectric transduction in an acoustic energy harvester using dual Helmholtz resonators has been reported. The harvester uses a pair of cavities mechanically coupled with a compliant perforated plate to enhance the acoustic coupling between the cavity and the plate. The experimental results show that the volume optimization of the second cavity can significantly increase the generated electric voltage up to 400% and raise the output power to 16 times as large as that of a harvester using a single Helmholtz resonator at resonant frequencies primarily related to the plate. PMID:24081260

  12. Acoustic Monitoring of Beluga Whale Interactions with Cook Inlet Tidal Energy Project

    SciTech Connect

    Worthington, Monty

    2014-02-05

    Cook Inlet, Alaska is home to some of the greatest tidal energy resources in the U.S., as well as an endangered population of beluga whales (Delphinapterus leucas). Successfully permitting and operating a tidal power project in Cook Inlet requires a biological assessment of the potential and realized effects of the physical presence and sound footprint of tidal turbines on the distribution, relative abundance, and behavior of Cook Inlet beluga whales. ORPC Alaska, working with the Project Team—LGL Alaska Research Associates, University of Alaska Anchorage, TerraSond, and Greeneridge Science—undertook the following U.S. Department of Energy (DOE) study to characterize beluga whales in Cook Inlet – Acoustic Monitoring of Beluga Whale Interactions with the Cook Inlet Tidal Energy Project (Project). ORPC Alaska, LLC, is a wholly-owned subsidiary of Ocean Renewable Power Company, LLC, (collectively, ORPC). ORPC is a global leader in the development of hydrokinetic power systems and eco-conscious projects that harness the power of ocean and river currents to create clean, predictable renewable energy. ORPC is developing a tidal energy demonstration project in Cook Inlet at East Foreland where ORPC has a Federal Energy Regulatory Commission (FERC) preliminary permit (P-13821). The Project collected baseline data to characterize pre-deployment patterns of marine mammal distribution, relative abundance, and behavior in ORPC’s proposed deployment area at East Foreland. ORPC also completed work near Fire Island where ORPC held a FERC preliminary permit (P-12679) until March 6, 2013. Passive hydroacoustic devices (previously utilized with bowhead whales in the Beaufort Sea) were adapted for study of beluga whales to determine the relative abundance of beluga whale vocalizations within the proposed deployment areas. Hydroacoustic data collected during the Project were used to characterize the ambient acoustic environment of the project site pre-deployment to inform the

  13. Acoustic Noise Alters Selective Attention Processes as Indicated by Direct Current (DC) Brain Potential Changes

    PubMed Central

    Trimmel, Karin; Schätzer, Julia; Trimmel, Michael

    2014-01-01

    Acoustic environmental noise, even of low to moderate intensity, is known to adversely affect information processing in animals and humans via attention mechanisms. In particular, facilitation and inhibition of information processing are basic functions of selective attention. Such mechanisms can be investigated by analyzing brain potentials under conditions of externally directed attention (intake of environmental information) versus internally directed attention (rejection of environmental stimuli and focusing on memory/planning processes). This study investigated brain direct current (DC) potential shifts—which are discussed to represent different states of cortical activation—of tasks that require intake and rejection of environmental information under noise. It was hypothesized that without background noise rejection tasks would show more positive DC potential changes compared to intake tasks and that under noise both kinds of tasks would show positive DC shifts as an expression of cortical inhibition caused by noise. DC potential shifts during intake and rejection tasks were analyzed at 16 standard locations in 45 persons during irrelevant speech or white noise vs. control condition. Without noise, rejection tasks were associated with more positive DC potential changes compared to intake tasks. During background noise, however, this difference disappeared and both kinds of tasks led to positive DC shifts. Results suggest—besides some limitations—that noise modulates selective attention mechanisms by switching to an environmental information processing and noise rejection mode, which could represent a suggested “attention shift”. Implications for fMRI studies as well as for public health in learning and performance environments including susceptible persons are discussed. PMID:25264675

  14. Breaking the acoustic diffraction limit via nonlinear effect and thermal confinement for potential deep-tissue high-resolution imaging

    PubMed Central

    Yuan, Baohong; Pei, Yanbo; Kandukuri, Jayanth

    2013-01-01

    Our recently developed ultrasound-switchable fluorescence (USF) imaging technique showed that it was feasible to conduct high-resolution fluorescence imaging in a centimeter-deep turbid medium. Because the spatial resolution of this technique highly depends on the ultrasound-induced temperature focal size (UTFS), minimization of UTFS becomes important for further improving the spatial resolution USF technique. In this study, we found that UTFS can be significantly reduced below the diffraction-limited acoustic intensity focal size via nonlinear acoustic effects and thermal confinement by appropriately controlling ultrasound power and exposure time, which can be potentially used for deep-tissue high-resolution imaging. PMID:23479498

  15. Exam Question Exchange: Potential Energy Surfaces.

    ERIC Educational Resources Information Center

    Alexander, John J., Ed.

    1988-01-01

    Presents three examination questions, graded in difficulty, that explore the topic of potential energy surfaces using a diagrammatic approach. Provides and discusses acceptable solutions including diagrams. (CW)

  16. Nonlinear dust acoustic waves in a mixed nonthermal high energy-tail electron distribution

    SciTech Connect

    Younsi, Smain; Tribeche, Mouloud

    2008-07-15

    Large amplitude as well as weakly nonlinear dust acoustic waves in a mixed nonthermal high-energy-tail electron distribution are investigated. The effects of charge variation and electron deviation from Boltzmann distribution on the large amplitude dust acoustic soliton are then considered. The dust charge variation leads to an additional enlargement of the dust acoustic soliton, which is more pronounced as the electrons evolve far away from Maxwell-Boltzmann distribution. Under certain conditions, the dust charge fluctuation may provide an alternate physical mechanism causing anomalous dissipation, the strength of which becomes important and may prevail over that of dispersion as the suprathermal character of the plasma becomes important. The results complement and provide new insights into our previously published results on this problem [K. Aoutou, M. Tribeche, and T. H. Zerguini, Phys. Plasmas 15, 013702 (2008)].

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

    SciTech Connect

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

    2010-08-25

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

  18. Applications of velocity potential function to acoustic duct propagation and radiation from inlets using finite element theory

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.; Majjigi, R. K.

    1979-01-01

    A finite element velocity potential program has been developed to study acoustic wave propagation in complex geometries. For irrotational flows, relatively low sound frequencies, and plane wave input, the finite element solutions show significant effects of inlet curvature and flow gradients on the attenuation of a given acoustic liner in a realistic variable area turbofan inlet. In addition, as shown in the paper, the velocity potential approach can not be used to estimate the effects of rotational flow on acoustic propagation since the potential acoustic disturbances propagate at the speed of the media in sheared flow. Approaches are discussed that are being considered for extending the finite element solution to include the far field as well as the internal portion of the duct. A new matrix partitioning approach is presented that can be incorporated in previously developed programs to allow the finite element calculation to be marched into the far field. The partitioning approach provides a large reduction in computer storage and running times.

  19. Tracking Energy Flow Using a Volumetric Acoustic Intensity Imager (VAIM)

    NASA Technical Reports Server (NTRS)

    Klos, Jacob; Williams, Earl G.; Valdivia, Nicolas P.

    2006-01-01

    A new measurement device has been invented at the Naval Research Laboratory which images instantaneously the intensity vector throughout a three-dimensional volume nearly a meter on a side. The measurement device consists of a nearly transparent spherical array of 50 inexpensive microphones optimally positioned on an imaginary spherical surface of radius 0.2m. Front-end signal processing uses coherence analysis to produce multiple, phase-coherent holograms in the frequency domain each related to references located on suspect sound sources in an aircraft cabin. The analysis uses either SVD or Cholesky decomposition methods using ensemble averages of the cross-spectral density with the fixed references. The holograms are mathematically processed using spherical NAH (nearfield acoustical holography) to convert the measured pressure field into a vector intensity field in the volume of maximum radius 0.4 m centered on the sphere origin. The utility of this probe is evaluated in a detailed analysis of a recent in-flight experiment in cooperation with Boeing and NASA on NASA s Aries 757 aircraft. In this experiment the trim panels and insulation were removed over a section of the aircraft and the bare panels and windows were instrumented with accelerometers to use as references for the VAIM. Results show excellent success at locating and identifying the sources of interior noise in-flight in the frequency range of 0 to 1400 Hz. This work was supported by NASA and the Office of Naval Research.

  20. Low frequency acoustic energy harvesting using PZT piezoelectric plates in a straight tube resonator

    NASA Astrophysics Data System (ADS)

    Li, Bin; You, Jeong Ho; Kim, Yong-Joe

    2013-05-01

    A novel and practical acoustic energy harvesting mechanism to harvest traveling sound at low audible frequency is introduced and studied both experimentally and numerically. The acoustic energy harvester in this study contains a quarter-wavelength straight tube resonator with lead zirconate titanate (PZT) piezoelectric cantilever plates placed inside the tube. When the tube resonator is excited by an incident sound at its acoustic resonance frequency, the amplified acoustic pressure inside the tube drives the vibration motions of piezoelectric plates, resulting in the generation of electricity. To increase the total voltage and power, multiple PZT plates were placed inside the tube. The number of PZT plates to maximize the voltage and power is limited due to the interruption of air particle motion by the plates. It has been found to be more beneficial to place the piezoelectric plates in the first half of the tube rather than along the entire tube. With an incident sound pressure level of 100 dB, an output voltage of 5.089 V was measured. The output voltage increases linearly with the incident sound pressure. With an incident sound pressure of 110 dB, an output voltage of 15.689 V and a power of 12.697 mW were obtained. The corresponding areal and volume power densities are 0.635 mW cm-2 and 15.115 μW cm-3, respectively.

  1. Implosion of an underwater spark-generated bubble and acoustic energy evaluation using the Rayleigh model.

    PubMed

    Buogo, Silvano; Cannelli, Giovanni B

    2002-06-01

    The growth, collapse, and rebound of a vapor bubble generated by an underwater spark is studied by means of high-speed cinematography, simultaneously acquiring the emitted acoustic signature. Video recordings show that the growth and collapse phases are nearly symmetrical during the first two or three cycles, the bubble shape being approximately spherical. After 2-3 cycles the bubble behavior changes from a collapsing/rebounding regime with sound-emitting implosions to a pulsating regime with no implosions. The motion of the bubble wall during the first collapses was found to be consistent with the Rayleigh model of a cavity in an incompressible liquid, with the inclusion of a vapor pressure term at constant temperature within each bubble cycle. An estimate of the pressure inside the bubble is obtained measuring the collapse time and maximum radius, and the amount of energy converted into acoustical energy upon each implosion is deduced. The resulting value of acoustic efficiency was found to be in agreement with measurements based on the emitted acoustic pulse. PMID:12083190

  2. A potential means of using acoustic emission for crack detection under cyclic-load conditions.

    NASA Technical Reports Server (NTRS)

    Vary, A.; Klima, S. J.

    1973-01-01

    A preliminary investigation was conducted to assess the feasibility of monitoring acoustic emission signals from fatigue cracks during cyclic bend tests. Plate specimens of 6Al-4V titanium, 2219-T87 aluminum, and 18-Ni maraging steel were tested with and without crack starter notches. It was found that significant acoustic emission signals could be detected in the frequency range from 100 to 400 kHz. Cracks emanating from starter notches were monitored by the ultrasonic pulse-echo technique and periodically measured by micro-optical examination. The investigation indicated that it was possible to extract meaningful acoustic emission signals in a cyclic bend machine environment.

  3. Spatio-temporal source modeling of evoked potentials to acoustic and cochlear implant stimulation.

    PubMed

    Ponton, C W; Don, M; Waring, M D; Eggermont, J J; Masuda, A

    1993-01-01

    Spatio-temporal source modeling (STSM) of event-related potentials was used to estimate the loci and characteristics of cortical activity evoked by acoustic stimulation in normal hearing subjects and by electrical stimulation in cochlear implant (CI) subjects. In both groups of subjects, source solutions obtained for the N1/P2 complex were located in the superior half of the temporal lobe in the head model. Results indicate that it may be possible to determine whether stimulation of different implant channels activates different regions of cochleotopically organized auditory cortex. Auditory system activation can be assessed further by examining the characteristics of the source wave forms. For example, subjects whose cochlear implants provided auditory sensations and normal hearing subjects had similar source activity. In contrast, a subject in whom implant activation evoked eyelid movements exhibited different source wave forms. STSM analysis may provide an electrophysiological technique for guiding rehabilitation programs based on the capabilities of the individual implant user and for disentangling the complex response patterns to electrical stimulation of the brain. PMID:7694834

  4. Acoustic Cavitation: A Potential Remediation Technology for On-Site Elimination of Perfluorinated Contaminants

    NASA Astrophysics Data System (ADS)

    Vecitis, C. D.; Cheng, J.; Park, H.; Hoffmann, M. R.

    2006-12-01

    Perfluorinated chemicals are emerging as globally ubiquitous contaminants which are recalcitrant to the conventional remediation techniques of adsorption and chemical oxidation. The release of these chemicals to the environment occurs from specific sites such as manufacturing plants, fire-fighting foams at airports and contaminated landfills. Even though these compounds are widely recognized as potentially hazardous, disposal regulations have been limited due to the ineffectiveness of current pump and treat technologies towards these species. We have shown that ultrasonically induced acoustic cavitation can effectively mineralize aqueous perfluorinated acid and sulfonate species by in situ pyrolysis and chemical oxidation at the lab and pilot scale. Efficiency has been tested on a variety of matrices such as tap water, groundwater and landfill pump-out with VOC content being the major detriment towards remediation. Advanced oxidation by the simultaneously application of ozone and ultrasound seems to partially eliminate this barrier by enhancing the rate of VOC mineralization. Application of this technology to a contaminated field site and the obstacles of scaling to such a degree are discussed.

  5. Energy potential of modern landfills

    SciTech Connect

    Bogner, J.E.

    1990-01-01

    Methane produced by refuse decomposition in a sanitary landfill can be recovered for commercial use. Landfill methane is currently under-utilized, with commercial recovery at only a small percentage of US landfills. New federal regulations mandating control of landfill gas migration and atmospheric emissions are providing impetus to methane recovery schemes as a means of recovering costs for increased environmental control. The benefits of landfill methane recovery include utilization of an inexpensive renewable energy resource, removal of explosive gas mixtures from the subsurface, and mitigation of observed historic increases in atmospheric methane. Increased commercial interest in landfill methane recovery is dependent on the final form of Clean Air Act amendments pertaining to gaseous emissions from landfills; market shifts in natural gas prices; financial incentives for development of renewable energy resources; and support for applied research and development to develop techniques for increased control of the gas generation process in situ. This paper will discuss the controls on methane generation in landfills. In addition, it will address how landfill regulations affect landfill design and site management practices which, in turn, influence decomposition rates. Finally, future trends in landfilling, and their relationship to gas production, will be examined. 19 refs., 2 figs., 3 tabs.

  6. Geothermal Energy Potential in Western United States

    ERIC Educational Resources Information Center

    Pryde, Philip R.

    1977-01-01

    Reviews types of geothermal energy sources in the western states, including hot brine systems and dry steam systems. Conversion to electrical energy is a major potential use of geothermal energy, although it creates environmental disruptions such as noise, corrosion, and scaling of equipment. (AV)

  7. Assessing the Underwater Acoustics of the World's Largest Vibration Hammer (OCTA-KONG) and Its Potential Effects on the Indo-Pacific Humpbacked Dolphin (Sousa chinensis)

    PubMed Central

    Wang, Zhitao; Wu, Yuping; Duan, Guoqin; Cao, Hanjiang; Liu, Jianchang; Wang, Kexiong; Wang, Ding

    2014-01-01

    Anthropogenic noise in aquatic environments is a worldwide concern due to its potential adverse effects on the environment and aquatic life. The Hongkong-Zhuhai-Macao Bridge is currently under construction in the Pearl River Estuary, a hot spot for the Indo-Pacific humpbacked dolphin (Sousa chinensis) in China. The OCTA-KONG, the world's largest vibration hammer, is being used during this construction project to drive or extract steel shell piles 22 m in diameter. This activity poses a substantial threat to marine mammals, and an environmental assessment is critically needed. The underwater acoustic properties of the OCTA-KONG were analyzed, and the potential impacts of the underwater acoustic energy on Sousa, including auditory masking and physiological impacts, were assessed. The fundamental frequency of the OCTA-KONG vibration ranged from 15 Hz to 16 Hz, and the noise increments were below 20 kHz, with a dominant frequency and energy below 10 kHz. The resulting sounds are most likely detectable by Sousa over distances of up to 3.5 km from the source. Although Sousa clicks do not appear to be adversely affected, Sousa whistles are susceptible to auditory masking, which may negatively impact this species' social life. Therefore, a safety zone with a radius of 500 m is proposed. Although the zero-to-peak source level (SL) of the OCTA-KONG was lower than the physiological damage level, the maximum root-mean-square SL exceeded the cetacean safety exposure level on several occasions. Moreover, the majority of the unweighted cumulative source sound exposure levels (SSELs) and the cetacean auditory weighted cumulative SSELs exceeded the acoustic threshold levels for the onset of temporary threshold shift, a type of potentially recoverable auditory damage resulting from prolonged sound exposure. These findings may aid in the identification and design of appropriate mitigation methods, such as the use of air bubble curtains, “soft start” and “power down

  8. Assessing the underwater acoustics of the world's largest vibration hammer (OCTA-KONG) and its potential effects on the Indo-Pacific humpbacked dolphin (Sousa chinensis).

    PubMed

    Wang, Zhitao; Wu, Yuping; Duan, Guoqin; Cao, Hanjiang; Liu, Jianchang; Wang, Kexiong; Wang, Ding

    2014-01-01

    Anthropogenic noise in aquatic environments is a worldwide concern due to its potential adverse effects on the environment and aquatic life. The Hongkong-Zhuhai-Macao Bridge is currently under construction in the Pearl River Estuary, a hot spot for the Indo-Pacific humpbacked dolphin (Sousa chinensis) in China. The OCTA-KONG, the world's largest vibration hammer, is being used during this construction project to drive or extract steel shell piles 22 m in diameter. This activity poses a substantial threat to marine mammals, and an environmental assessment is critically needed. The underwater acoustic properties of the OCTA-KONG were analyzed, and the potential impacts of the underwater acoustic energy on Sousa, including auditory masking and physiological impacts, were assessed. The fundamental frequency of the OCTA-KONG vibration ranged from 15 Hz to 16 Hz, and the noise increments were below 20 kHz, with a dominant frequency and energy below 10 kHz. The resulting sounds are most likely detectable by Sousa over distances of up to 3.5 km from the source. Although Sousa clicks do not appear to be adversely affected, Sousa whistles are susceptible to auditory masking, which may negatively impact this species' social life. Therefore, a safety zone with a radius of 500 m is proposed. Although the zero-to-peak source level (SL) of the OCTA-KONG was lower than the physiological damage level, the maximum root-mean-square SL exceeded the cetacean safety exposure level on several occasions. Moreover, the majority of the unweighted cumulative source sound exposure levels (SSELs) and the cetacean auditory weighted cumulative SSELs exceeded the acoustic threshold levels for the onset of temporary threshold shift, a type of potentially recoverable auditory damage resulting from prolonged sound exposure. These findings may aid in the identification and design of appropriate mitigation methods, such as the use of air bubble curtains, "soft start" and "power down" techniques. PMID

  9. Animal study assessing safety of an acoustic coupling fluid that holds the potential to avoid surgically induced artifacts in 3D ultrasound guided operations

    PubMed Central

    2014-01-01

    Background Use of ultrasound in brain tumor surgery is common. The difference in attenuation between brain and isotonic saline may cause artifacts that degrade the ultrasound images, potentially affecting resection grades and safety. Our research group has developed an acoustic coupling fluid that attenuates ultrasound energy like the normal brain. We aimed to test in animals if the newly developed acoustic coupling fluid may have harmful effects. Methods Eight rats were included for intraparenchymal injection into the brain, and if no adverse reactions were detected, 6 pigs were to be included with injection of the coupling fluid into the subarachnoid space. Animal behavior, EEG registrations, histopathology and immunohistochemistry were used in assessment. Results In total, 14 animals were included, 8 rats and 6 pigs. We did not detect any clinical adverse effects, seizure activity on EEG or histopathological signs of tissue damage. Conclusion The novel acoustic coupling fluid intended for brain tumor surgery appears safe in rats and pigs under the tested circumstances. PMID:24666721

  10. PEDOT as a Flexible Organic Electrode for a Thin Film Acoustic Energy Harvester.

    PubMed

    Kim, Younghoon; Na, Jongbeom; Park, Chihyun; Shin, Haijin; Kim, Eunkyoung

    2015-08-01

    An efficient thin film acoustic energy harvester was explored using flexible poly(3,4-ethylene dioxythiophene) (PEDOT) films as electrodes in an all-organic triboelectric generator (AO-TEG). A thin film AO-TEG structured as PEDOT/Kapton//PET/PEDOT was prepared by the solution casting polymerization(SCP) on the dielectric polymer films. As-prepared AO-TEG showed high flexibility and durability due to the strong adhesion between the electrodes and the dielectric polymer. The short-circuit current density (Jsc), open-circuit voltage (Voc), and maximum power density (Pw) reached 50 mA/m(2), 700 V, and 12.9 W/m(2) respectively. The output current density decreased with the increase in the electrode resistance (Re), but the energy loss in the organic electrodes was negligible. The AO-TEG could light up 180 LEDs instantaneously upon touching of the AO-TEG with a palm (∼120 N). With the flexible structure, the AO-TEG was worn as clothes and generated electricity to light LEDs upon regular human movement. Furthermore, the AO-TEG was applicable as a thin film acoustic energy harvester, which used music to generate electricity enough for powering of 5 LEDs. An AO-TEG with a PEDOT electrode (Re = 200 Ω) showed instantaneous peak-to-peak voltage generation of 11 V under a sound pressure level (SPL) of 90-100 dB. The harvested acoustic energy through the AO-TEG was 350 μJ from the 4 min playing of the same single song. This is the first demonstration of a flexible triboelectric generator (TEG) using an organic electrode for harvesting acoustic energy from ambient environment. PMID:26153798

  11. Generalized acoustic energy density based active noise control in single frequency diffuse sound fields.

    PubMed

    Xu, Buye; Sommerfeldt, Scott D

    2014-09-01

    In a diffuse sound field, prior research has established that a secondary source can theoretically achieve perfect cancellation at an error microphone in the far field of the secondary source. However, the sound pressure level is generally only reduced in a small zone around the error sensor, and at a distance half of a wavelength away from the error sensor, the averaged sound pressure level will be increased by more than 10 dB. Recently an acoustic energy quantity, referred to as the generalized acoustic energy density (GED), has been introduced. The GED is obtained by using a weighting factor in the formulation of total acoustic energy density. Different values of the weighting factor can be chosen for different applications. When minimizing the GED at the error sensor, one can adjust the weighting factor to increase the spatial extent of the "quiet zone" and to achieve a desired balance between the degree of attenuation in the quiet zone and the total energy added into the sound field. PMID:25190386

  12. Effect of wind and temperature gradients on received acoustic energy

    NASA Technical Reports Server (NTRS)

    Brienzo, Richard K.

    1990-01-01

    The effect of refraction due to wind and temperature gradients on energy received from low flying aircraft is examined. A series of helicopter and jet flyby's were recorded with a microphone array on two separate days, each with distinctly different meteorological conditions. Energy in the 100 to 200 Hertz band is shown as a function of aircraft range from the array, and compared with the output of the Fast Field Program.

  13. 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.

  14. Wave Energy Potential in the Latvian EEZ

    NASA Astrophysics Data System (ADS)

    Beriņš, J.; Beriņš, J.; Kalnačs, J.; Kalnačs, A.

    2016-06-01

    The present article deals with one of the alternative forms of energy - sea wave energy potential in the Latvian Exclusice Economic Zone (EEZ). Results have been achieved using a new method - VEVPP. Calculations have been performed using the data on wave parameters over the past five years (2010-2014). We have also considered wave energy potential in the Gulf of Riga. The conclusions have been drawn on the recommended methodology for the sea wave potential and power calculations for wave-power plant pre-design stage.

  15. Negative Refraction and Energy Funneling by Hyperbolic Materials: An Experimental Demonstration in Acoustics

    NASA Astrophysics Data System (ADS)

    García-Chocano, Victor M.; Christensen, Johan; Sánchez-Dehesa, José

    2014-04-01

    This Letter reports the design, fabrication, and experimental characterization of hyperbolic materials showing negative refraction and energy funneling of airborne sound. Negative refraction is demonstrated using a stack of five holey Plexiglas plates where their thicknesses, layer separation, hole diameters, and lattice periodicity have been determined to show hyperbolic dispersion around 40 kHz. The resulting hyperbolic material shows a flat band profile in the equifrequency contour allowing the gathering of acoustic energy in a broad range of incident angles and its funneling through the material. Our demonstrations foresee interesting developments based on both phenomena. Acoustic imaging with subwavelength resolution and spot-size converters that harvest and squeeze sound waves irradiating from many directions into a collimated beam are just two possible applications among many.

  16. Acoustic noise and pneumatic wave vortices energy harvesting on highways

    NASA Astrophysics Data System (ADS)

    Pogacian, S.; Bot, A.; Zotoiu, D.

    2012-02-01

    This paper is aimed to present the structure and the principle of a energy harvesting system that uses the air movement emanated from passing traffic to produce and accumulate electrical energy. Each of the system's elements consists of a inertial mass panel which oscillate when driving cars pass. The panel is attached to a linear electromagnetic mini generator (or/and some piezo electric micro generators) and at the time of passing, it produces energy which is store it in a supercapacitor or in a rechargeable battery. The concept can be applied to busy roads, and to high-frequented rail networks and it can work with street and road lighting, information panels and monitoring devices.

  17. Study of low-frequency-acoustic- and seismic-wave energy propagation on the shelf

    NASA Astrophysics Data System (ADS)

    Rutenko, A. N.; Manul'chev, D. S.; Solov'ev, A. A.

    2013-05-01

    The paper presents the results of field and numerical studies on the features of low-frequency-acoustic- and seismic-wave energy propagation on the shelf of the Sea of Japan. Measurements were conducted with the Mollusk-07 autonomous vertical acousto-hydrophysical measurement system, an electromagnetic low-frequency resonance emitter, and a pulsed pneumoemitter lowered from the ship, as well as a shore-based resonance seismoemitter.

  18. Energy monitoring and analysis during deformation of bedded-sandstone: use of acoustic emission.

    PubMed

    Wasantha, P L P; Ranjith, P G; Shao, S S

    2014-01-01

    This paper investigates the mechanical behaviour and energy releasing characteristics of bedded-sandstone with bedding layers in different orientations, under uniaxial compression. Cylindrical sandstone specimens (54 mm diameter and 108 mm height) with bedding layers inclined at angles of 10°, 20°, 35°, 55°, and 83° to the minor principal stress direction, were produced to perform a series of Uniaxial Compressive Strength (UCS) tests. One of the two identical sample sets was fully-saturated with water before testing and the other set was tested under dry conditions. An acoustic emission system was employed in all the testing to monitor the acoustic energy release during the whole deformation process of specimens. From the test results, the critical joint orientation was observed as 55° for both dry and saturated samples and the peak-strength losses due to water were 15.56%, 20.06%, 13.5%, 13.2%, and 13.52% for the bedding orientations 10°, 20°, 35°, 55°, and 83°, respectively. The failure mechanisms for the specimens with bedding layers in 10°, 20° orientations showed splitting type failure, while the specimens with bedding layers in 55°, 83° orientations were failed by sliding along a weaker bedding layer. The failure mechanism for the specimens with bedding layers in 35° orientation showed a mixed failure mode of both splitting and sliding types. Analysis of the acoustic energy, captured from the acoustic emission detection system, revealed that the acoustic energy release is considerably higher in dry specimens than that of the saturated specimens at any bedding orientation. In addition, higher energy release was observed for specimens with bedding layers oriented in shallow angles (which were undergoing splitting type failures), whereas specimens with steeply oriented bedding layers (which were undergoing sliding type failures) showed a comparatively less energy release under both dry and saturated conditions. Moreover, a considerable amount of

  19. Intermolecular potential energy surface and thermophysical properties of ethylene oxide

    SciTech Connect

    Crusius, Johann-Philipp Hassel, Egon; Hellmann, Robert; Bich, Eckard

    2014-10-28

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C{sub 2}H{sub 4}O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide.

  20. Intermolecular potential energy surface and thermophysical properties of ethylene oxide.

    PubMed

    Crusius, Johann-Philipp; Hellmann, Robert; Hassel, Egon; Bich, Eckard

    2014-10-28

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C2H4O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide. PMID:25362314

  1. Wind energy in China: Estimating the potential

    NASA Astrophysics Data System (ADS)

    Yuan, Jiahai

    2016-07-01

    Persistent and significant curtailment has cast concern over the prospects of wind power in China. A comprehensive assessment of the production of energy from wind has identified grid-integrated wind generation potential at 11.9–14% of China's projected energy demand by 2030.

  2. Potential of energy production from conserved forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forages have a potential role in meeting the demand for energy. Perennial forages are attractive for various reasons. One, both the monetary and energy cost of planting is spread over many years. Two, we already have the equipment for harvesting, storing and transporting this source of biomass. Thre...

  3. Theoretical studies of potential energy surfaces

    SciTech Connect

    Harding, L.B.

    1995-07-01

    MRCI (configuration interaction) calculations were used to examine possible pathways for the O{sub 2} + CCH reaction. The H{sub 2} + CN potential surface was examined. An initial survey was made of the HCl + CN potential energy surface at a low level of theory.

  4. A potential means of using acoustic emission for crack detection under cyclic-load conditions

    NASA Technical Reports Server (NTRS)

    Vary, A.; Klima, S. J.

    1973-01-01

    A preliminary investigation was conducted to assess the feasibility of monitoring acoustic emission signals from fatigue cracks during cyclic bend tests. Plate specimens of 6A1-4V titanium, 2219-T87 aluminum, and 18-Ni maraging steel were tested with and without crack starter notches. It was found that significant acoustic emission signals could be detected in the frequency range from 100 kHz to 400 kHz. Cracks emanating from starter notches were monitored by the ultrasonic pulse-echo technique and periodically measured by micro-optical examination. Methods used to reduce the effects of extraneous noises (i.e., machine noises, fretting) are described. A frequency spectrum analyzer was used to characterize the emissions and to evaluate methods used to acquire the signals (i.e., transducer location, bandwidth selection). The investigation indicated that it was possible to extract meaningful acoustic emission signals in a cyclic bend machine environment.

  5. Economic Energy Savings Potential in Federal Buildings

    SciTech Connect

    Brown, Daryl R.; Dirks, James A.; Hunt, Diane M.

    2000-09-04

    The primary objective of this study was to estimate the current life-cycle cost-effective (i.e., economic) energy savings potential in Federal buildings and the corresponding capital investment required to achieve these savings, with Federal financing. Estimates were developed for major categories of energy efficiency measures such as building envelope, heating system, cooling system, and lighting. The analysis was based on conditions (building stock and characteristics, retrofit technologies, interest rates, energy prices, etc.) existing in the late 1990s. The potential impact of changes to any of these factors in the future was not considered.

  6. Note: High-efficiency broadband acoustic energy harvesting using Helmholtz resonator and dual piezoelectric cantilever beams

    SciTech Connect

    Yang, Aichao; Li, Ping Wen, Yumei; Lu, Caijiang; Peng, Xiao; He, Wei; Zhang, Jitao; Wang, Decai; Yang, Feng

    2014-06-15

    A high-efficiency broadband acoustic energy harvester consisting of a compliant-top-plate Helmholtz resonator (HR) and dual piezoelectric cantilever beams is proposed. Due to the high mechanical quality factor of beams and the strong multimode coupling of HR cavity, top plate and beams, the high efficiency in a broad bandwidth is obtained. Experiment exhibits that the proposed harvester at 170–206 Hz has 28–188 times higher efficiency than the conventional harvester using a HR with a piezoelectric composite diaphragm. For input acoustic pressure of 2.0 Pa, the proposed harvester exhibits 0.137–1.43 mW output power corresponding to 0.035–0.36 μW cm{sup −3} volume power density at 170–206 Hz.

  7. Note: High-efficiency broadband acoustic energy harvesting using Helmholtz resonator and dual piezoelectric cantilever beams.

    PubMed

    Yang, Aichao; Li, Ping; Wen, Yumei; Lu, Caijiang; Peng, Xiao; He, Wei; Zhang, Jitao; Wang, Decai; Yang, Feng

    2014-06-01

    A high-efficiency broadband acoustic energy harvester consisting of a compliant-top-plate Helmholtz resonator (HR) and dual piezoelectric cantilever beams is proposed. Due to the high mechanical quality factor of beams and the strong multimode coupling of HR cavity, top plate and beams, the high efficiency in a broad bandwidth is obtained. Experiment exhibits that the proposed harvester at 170-206 Hz has 28-188 times higher efficiency than the conventional harvester using a HR with a piezoelectric composite diaphragm. For input acoustic pressure of 2.0 Pa, the proposed harvester exhibits 0.137-1.43 mW output power corresponding to 0.035-0.36 μW cm(-3) volume power density at 170-206 Hz. PMID:24985867

  8. Note: High-efficiency broadband acoustic energy harvesting using Helmholtz resonator and dual piezoelectric cantilever beams

    NASA Astrophysics Data System (ADS)

    Yang, Aichao; Li, Ping; Wen, Yumei; Lu, Caijiang; Peng, Xiao; He, Wei; Zhang, Jitao; Wang, Decai; Yang, Feng

    2014-06-01

    A high-efficiency broadband acoustic energy harvester consisting of a compliant-top-plate Helmholtz resonator (HR) and dual piezoelectric cantilever beams is proposed. Due to the high mechanical quality factor of beams and the strong multimode coupling of HR cavity, top plate and beams, the high efficiency in a broad bandwidth is obtained. Experiment exhibits that the proposed harvester at 170-206 Hz has 28-188 times higher efficiency than the conventional harvester using a HR with a piezoelectric composite diaphragm. For input acoustic pressure of 2.0 Pa, the proposed harvester exhibits 0.137-1.43 mW output power corresponding to 0.035-0.36 μW cm-3 volume power density at 170-206 Hz.

  9. Effective parameters in beam acoustic metamaterials based on energy band structures

    NASA Astrophysics Data System (ADS)

    Jing, Li; Wu, Jiu Hui; Guan, Dong; Hou, Mingming; Kuan, Lu; Shen, Li

    2016-07-01

    We present a method to calculate the effective material parameters of beam acoustic metamaterials. The effective material parameters of a periodic beam are calculated as an example. The dispersion relations and energy band structures of this beam are calculated. Subsequently, the effective material parameters of the beam are investigated by using the energy band structures. Then, the modal analysis and transmission properties of the beams with finite cells are simulated in order to confirm the correctness of effective approximation. The results show that the periodic beam can be equivalent to the homogeneous beam with dynamic effective material parameters in passband.

  10. Investigation of the nature of thermal stimulation of acoustic emission

    SciTech Connect

    Muravin, G.B.; Ship, V.V.; Lezvinskaya, L.M.

    1988-12-01

    The nature of thermal stimulation of acoustic emission was investigated. Data are given on the distribution of the density of the energy of deformation at a crack tip and the parameters of acoustic emission with different combinations of mechanical and thermal action. It was established that thermal stimulation of acoustic emission is related to advance and growth of a crack under the action of thermoelastic shear stresses. An increases in heating power causes an increase in the energy of deformation, shear stresses at the crack edges, and acoustic emission energy. The position of the minimum in the density of the energy of deformation and of the maximum in acoustic emission energy coincides with the direction of crack advance, which with the use of the method of thermally stimulated acoustic emission makes it possible to not only reveal crack-like defects but also to determine potentially dangerous directions of their development.

  11. Potential energy function for the hydroperoxyl radical

    SciTech Connect

    Lemon, W.J.; Hase, W.L.

    1987-03-12

    A switching function formalism is used to derive an analytic potential energy surface for the O + OH in equilibrium HO/sub 2/ in equilibrium H + O/sub 2/ reactive system. Both experimental and ab initio data are used to derive parameters for the potential energy surface. Trajectory calculations for highly excited HO/sub 2/ are performed on this surface. From these trajectories quasi-periodic eigentrajectories are found for vibrational levels near the HO/sub 2/ dissociation threshold with small amounts of quanta in the OH stretch mode and large amounts of quanta in the OO stretch mode.

  12. Ultralow frequency acoustic bandgap and vibration energy recovery in tetragonal folding beam phononic crystal

    NASA Astrophysics Data System (ADS)

    Gao, Nansha; Wu, Jiu Hui; Yu, Lie; Hou, Hong

    2016-06-01

    This paper investigates ultralow frequency acoustic properties and energy recovery of tetragonal folding beam phononic crystal (TFBPC) and its complementary structure. The dispersion curve relationships, transmission spectra and displacement fields of the eigenmodes are studied with FEA in detail. Compared with the traditional three layer phononic crystal (PC) structure, this structure proposed in this paper not only unfold bandgaps (BGs) in lower frequency range (below 300 Hz), but also has lighter weight because of beam structural cracks. We analyze the relevant physical mechanism behind this phenomenon, and discuss the effects of the tetragonal folding beam geometric parameters on band structure maps. FEM proves that the multi-cell structures with different arrangements have different acoustic BGs when compared with single cell structure. Harmonic frequency response and piezoelectric properties of TFBPC are specifically analyzed. The results confirm that this structure does have the recovery ability for low frequency vibration energy in environment. These conclusions in this paper could be indispensable to PC practical applications such as BG tuning and could be applied in portable devices, wireless sensor, micro-electro mechanical systems which can recycle energy from vibration environment as its own energy supply.

  13. Geothermal energy and its potential. [Utah

    SciTech Connect

    Berge, C.W.

    1980-06-01

    A brief review of geothermal energy and its potential as a future energy source is presented. The type of geothermal systems and their geologic occurrence is discussed, and the Phillips Petroleum Company's exploration and drilling programs in the Roosevelt Hot Springs area in parts of Iron, Beaver, and Millard Counties, Utah are detailed. A section on the rock behavior and mechanical properties of rocks in the Roosevelt Hot Springs area is included. (JMT)

  14. Enhancing the dynamic range of targeted energy transfer in acoustics using several nonlinear membrane absorbers

    NASA Astrophysics Data System (ADS)

    Bellet, R.; Cochelin, B.; Côte, R.; Mattei, P.-O.

    2012-12-01

    In order to enhance the robustness and the energy range of efficiency of targeted energy transfer (TET) phenomena in acoustics, we discuss in this paper about the use of multiple nonlinear membrane absorbers (called nonlinear energy sinks or NES) placed in parallel. We show this way, mainly thanks to an experimental set-up with two membranes, that the different absorbers have additional effects that extend the efficiency and the possibilities of observation of TET. More precisely, we present the different behavior of the system under sinusoidal forcing and free oscillations, characterizing the phenomena for all input energies. The frequency responses are also presented, showing successive clipping of the original resonance peak of the system, and strongly modulated regimes (SMR). A model is finally used to generalize these results to more than two NES and to simulate the case of several very similar membranes in parallel which shows how to extend the existence zone of TET.

  15. Biomass resource potential using energy crops

    SciTech Connect

    Wright, L.L.; Cushman, J.H.; Martin, S.A.

    1993-09-01

    Biomass energy crops can provide a significant and environmentally beneficial source of renewable energy feedstocks for the future. They can revitalize the agricultural sector of the US economy by providing profitable uses for marginal cropland. Energy crops include fast-growing trees, perennial grasses, and annual grasses, all capable of collecting solar energy and storing it as cellulosic compounds for several months to several years. Once solar energy is thus captured, it can be converted by means of currently available technologies to a wide variety of energy products such as electricity, heat, liquid transportation fuels, and gases. Experimental results from field trials have generated optimism that selected and improved energy crops, established on cropland with moderate limitations for crop production, have the potential for producing high yields. Both trees and grasses, under very good growing conditions, have produced average annual yields of 20 to 40 dry Mg ha{sup {minus}1} year{sup {minus}1}. Sorghum has shown especially high yields in the Midwest. Hybrids between sugar cane and its wild relatives, called energy cane, have yielded as much as 50 dry Mg ha{sup {minus}1} year{sup {minus}1} in Florida. These experimental results demonstrate that some species have the genetic potential for very rapid growth rates. New wood energy crop systems developed by the Department of Energy`s Biofuels Feedstock Development Program offer, at a minimum, a 100% increase in biomass production rates over the 2 to 4 Mg ha{sup {minus}1} year{sup {minus}1} of dry leafless woody biomass produced by most natural forest systems. Experimental data indicate that short rotation wood crops established on cropland with moderate limitations are capable of producing biomass yields of 8--20 dry Mg ha{sup {minus}1} year{sup {minus}1} with a present average about 11 dry Mg ha{sup {minus}1} year{sup {minus}1} on typical cropland sites.

  16. Potential reduction of DSN uplink energy cost

    NASA Technical Reports Server (NTRS)

    Dolinsky, S.; Degroot, N. F.

    1982-01-01

    DSN Earth stations typically transmit more power than that required to meet minimum specifications for uplink performance. Energy and cost savings that could result from matching the uplink power to the amount required for specified performance are studied. The Galileo mission was selected as a case study. Although substantial reduction in transmitted energy is possible, potential savings in source energy (oil or electricity) savings are much less. This is because of the rising inefficiency in power conversion and radio frequency power generation that accompanies reduced power output.

  17. Acoustically induced streaming flows near a model cod otolith and their potential implications for fish hearing.

    PubMed

    Kotas, Charlotte W; Rogers, Peter H; Yoda, Minami

    2011-08-01

    The ears of fishes are remarkable sensors for the small acoustic disturbances associated with underwater sound. For example, each ear of the Atlantic cod (Gadus morhua) has three dense bony bodies (otoliths) surrounded by fluid and tissue, and detects sounds at frequencies from 30 to 500 Hz. Atlantic cod have also been shown to localize sounds. However, how their ears perform these functions is not fully understood. Steady streaming, or time-independent, flows near a 350% scale model Atlantic cod otolith immersed in a viscous fluid were studied to determine if these fluid flows contain acoustically relevant information that could be detected by the ear's sensory hair cells. The otolith was oscillated sinusoidally at various orientations at frequencies of 8-24 Hz, corresponding to an actual frequency range of 280-830 Hz. Phase-locked particle pathline visualizations of the resulting flows give velocity, vorticity, and rate of strain fields over a single plane of this mainly two-dimensional flow. Although the streaming flows contain acoustically relevant information, the displacements due to these flows are likely too small to explain Atlantic cod hearing abilities near threshold. The results, however, may suggest a possible mechanism for detection of ultrasound in some fish species. PMID:21877817

  18. Acoustically Induced Streaming Flows near a Model Cod Otolith and their Potential Implications for Fish Hearing

    SciTech Connect

    Kotas, Charlotte W; Rogers, Peter; Yoda, Minami

    2011-01-01

    The ears of fishes are remarkable sensors for the small acoustic disturbances associated with underwater sound. For example, each ear of the Atlantic cod (Gadus morhua) has three dense bony bodies (otoliths) surrounded by fluid and tissue, and detects sounds at frequencies from 30 to 500 Hz. Atlantic cod have also been shown to localize sounds. However, how their ears perform these functions is not fully understood. Steady streaming, or time-independent, flows near a 350% scale model Atlantic cod otolith immersed in a viscous fluid were studied to determine if these fluid flows contain acoustically relevant information that could be detected by the ear s sensory hair cells. The otolith was oscillated sinusoidally at various orientations at frequencies of 8 24 Hz, corresponding to an actual frequency range of 280 830 Hz. Phaselocked particle pathline visualizations of the resulting flows give velocity, vorticity, and rate of strain fields over a single plane of this mainly two-dimensional flow. Although the streaming flows contain acoustically relevant information, the displacements due to these flows are likely too small to explain Atlantic cod hearing abilities near threshold. The results, however, may suggest a possible mechanism for detection of ultrasound in some fish species.

  19. Dyke leakage localization and hydraulic permeability estimation through self-potential and hydro-acoustic measurements: Self-potential 'abacus' diagram for hydraulic permeability estimation and uncertainty computation

    NASA Astrophysics Data System (ADS)

    Bolève, A.; Vandemeulebrouck, J.; Grangeon, J.

    2012-11-01

    In the present study, we propose the combination of two geophysical techniques, which we have applied to a dyke located in southeastern France that has a visible downstream flood area: the self-potential (SP) and hydro-acoustic methods. These methods are sensitive to two different types of signals: electric signals and water-soil pressure disturbances, respectively. The advantages of the SP technique lie in the high rate of data acquisition, which allows assessment of long dykes, and direct diagnosis in terms of leakage area delimitation and quantification. Coupled with punctual hydro-acoustic cartography, a leakage position can be precisely located, therefore allowing specific remediation decisions with regard to the results of the geophysical investigation. Here, the precise localization of leakage from an earth dyke has been identified using SP and hydro-acoustic signals, with the permeability of the preferential fluid flow area estimated by forward SP modeling. Moreover, we propose a general 'abacus' diagram for the estimation of hydraulic permeability of dyke leakage according to the magnitude of over water SP anomalies and the associated uncertainty.

  20. Potential energy studies on silane dimers

    NASA Astrophysics Data System (ADS)

    Mahlanen, Riina; Pakkanen, Tapani A.

    2011-04-01

    Intermolecular interactions and parameters for use in MD studies of large molecule systems have earlier been determined for hydrocarbons, carbon tetrahalides and sulfur. The paper reports a model representing nonbonding interactions between silane molecules, which were examined in the same way as hydrocarbons in an earlier (neopentane, isopropane, propane, and ethane) study. Intermolecular potentials were determined for 11 combinations of silane compound pairs (silane SiH 4, disilane Si 2H 6, trisilane Si 3H 8, isotetrasilane Si 4H 10 and neopentasilane Si 5H 12) with MP2/aug(df)-6-311G ∗ab initio calculations. The most stable dimer configurations were identified. With use of the modified Morse potential model to represent the interactions, 276 new potential energy surfaces were generated for silane dimers. Separate and generic pair potentials were calculated for the silanes. The pair potentials can be used in MD studies of silanes.

  1. An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Javaid, Nadeem; Shah, Mehreen; Ahmad, Ashfaq; Imran, Muhammad; Khan, Majid Iqbal; Vasilakos, Athanasios V.

    2016-01-01

    This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes. PMID:27070605

  2. An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks.

    PubMed

    Javaid, Nadeem; Shah, Mehreen; Ahmad, Ashfaq; Imran, Muhammad; Khan, Majid Iqbal; Vasilakos, Athanasios V

    2016-01-01

    This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes. PMID:27070605

  3. Potential energy savings from aquifer thermal energy storage

    SciTech Connect

    Anderson, M.R.; Weijo, R.O.

    1988-07-01

    Pacific Northwest Laboratory researchers developed an aggregate-level model to estimate the short- and long-term potential energy savings from using aquifer thermal storage (ATES) in the United States. The objectives of this effort were to (1) develop a basis from which to recommend whether heat or chill ATES should receive future research focus and (2) determine which market sector (residential, commercial, or industrial) offers the largest potential energy savings from ATES. Information was collected on the proportion of US land area suitable for ATES applications. The economic feasibility of ATES applications was then evaluated. The potential energy savings from ATES applications was calculated. Characteristic energy use in the residential, commercial, and industrial sectors was examined, as was the relationship between waste heat production and consumption by industrial end-users. These analyses provided the basis for two main conclusions: heat ATES applications offer higher potential for energy savings than do chill ATES applications; and the industrial sector can achieve the highest potential energy savings for the large consumption markets. Based on these findings, it is recommended that future ATES research and development efforts be directed toward heat ATES applications in the industrial sector. 11 refs., 6 figs., 9 tabs.

  4. Experimental analysis of the relationship between reverberant acoustic intensity and energy density inside long rooms.

    PubMed

    Visentin, Chiara; Prodi, Nicola; Valeau, Vincent; Picaut, Judicaël

    2015-07-01

    In this paper, the validity of the Fick's law of diffusion in room acoustics is experimentally investigated inside long rooms. The room-acoustics diffusion model relies on Fick's law stating a proportionality relationship between sound intensity and energy density gradient inside a room through a constant diffusion coefficient. This relationship is investigated in the stationary state for the particular case of long rooms with different amounts of boundary scattering. Measurements were performed inside a 1:16 scale model, using a p-u sound intensity probe (calibrated with digital filters) to collect concurrent data in terms of sound pressure and axial velocity components. Then for each receiver position, sound intensity and energy density gradient were derived. The results show that inside long rooms the diffusion coefficient is not a constant but increases with the distance from the source with a slope depending on the scattering coefficient of the walls. Numerical simulations of the enclosures were performed too by using a sound particle-tracing code; a substantial agreement with the experimental findings is observed. The results imply that for such long enclosures, the diffusion model should consider a space-varying diffusion coefficient to be more consistent with real phenomena. PMID:26233018

  5. Lightweight Filter Architecture for Energy Efficient Mobile Vehicle Localization Based on a Distributed Acoustic Sensor Network

    PubMed Central

    Kim, Keonwook

    2013-01-01

    The generic properties of an acoustic signal provide numerous benefits for localization by applying energy-based methods over a deployed wireless sensor network (WSN). However, the signal generated by a stationary target utilizes a significant amount of bandwidth and power in the system without providing further position information. For vehicle localization, this paper proposes a novel proximity velocity vector estimator (PVVE) node architecture in order to capture the energy from a moving vehicle and reject the signal from motionless automobiles around the WSN node. A cascade structure between analog envelope detector and digital exponential smoothing filter presents the velocity vector-sensitive output with low analog circuit and digital computation complexity. The optimal parameters in the exponential smoothing filter are obtained by analytical and mathematical methods for maximum variation over the vehicle speed. For stationary targets, the derived simulation based on the acoustic field parameters demonstrates that the system significantly reduces the communication requirements with low complexity and can be expected to extend the operation time considerably. PMID:23979482

  6. Lightweight filter architecture for energy efficient mobile vehicle localization based on a distributed acoustic sensor network.

    PubMed

    Kim, Keonwook

    2013-01-01

    The generic properties of an acoustic signal provide numerous benefits for localization by applying energy-based methods over a deployed wireless sensor network (WSN). However, the signal generated by a stationary target utilizes a significant amount of bandwidth and power in the system without providing further position information. For vehicle localization, this paper proposes a novel proximity velocity vector estimator (PVVE) node architecture in order to capture the energy from a moving vehicle and reject the signal from motionless automobiles around the WSN node. A cascade structure between analog envelope detector and digital exponential smoothing filter presents the velocity vector-sensitive output with low analog circuit and digital computation complexity. The optimal parameters in the exponential smoothing filter are obtained by analytical and mathematical methods for maximum variation over the vehicle speed. For stationary targets, the derived simulation based on the acoustic field parameters demonstrates that the system significantly reduces the communication requirements with low complexity and can be expected to extend the operation time considerably. PMID:23979482

  7. Energy balance of acoustic gravity waves above the polar caps according to the data of satellite measurements

    NASA Astrophysics Data System (ADS)

    Fedorenko, A. K.

    2010-02-01

    Wave disturbances of the Neutral Atmosphere above the polar caps are studied based on the Dynamic Explorer 2 satellite measurements. The characteristic spatial scales of these disturbances are 500— 600 km. Based on an analysis of the synchronous variations in different parameters, these disturbances were interpreted as propagating acoustic gravity waves (AGWs). The mass-spectrometer measurements of concentrations of individual atmospheric gases made it possible to determine the following AGW components: density of the acoustic compression, thermobaric, and average kinetic energies. It has been found out that the average (during the period) densities of the acoustic and thermobaric energies are approximately equal for polar AGWs. The results indicate that the contribution of these waves to the energy of the polar upper atmosphere is considerable.

  8. Potential energy hypersurface and molecular flexibility

    NASA Astrophysics Data System (ADS)

    Koča, Jaroslav

    1993-02-01

    The molecular flexibility phenomenon is discussed from the conformational potential energy(hyper) surface (PES) point of view. Flexibility is considered as a product of three terms: thermodynamic, kinetic and geometrical. Several expressions characterizing absolute and relative molecular flexibility are introduced, depending on a subspace studied of the entire conformational space, energy level E of PES as well as absolute temperature. Results obtained by programs DAISY, CICADA and PANIC in conjunction with molecular mechanics program MMX for flexibility analysis of isopentane, 2,2-dimethylpentane and isohexane molecules are introduced.

  9. Reverberant acoustic energy in auditoria that comprise systems of coupled rooms

    NASA Astrophysics Data System (ADS)

    Summers, Jason Erik

    A frequency-dependent model for levels and decay rates of reverberant energy in systems of coupled rooms is developed and compared with measurements conducted in a 1:10 scale model and in Bass Hall, Fort Worth, TX. Schroeder frequencies of subrooms, fSch, characteristic size of coupling apertures, a, relative to wavelength lambda, and characteristic size of room surfaces, l, relative to lambda define the frequency regions. At high frequencies [HF (f >> f Sch, a >> lambda, l >> lambda)], this work improves upon prior statistical-acoustics (SA) coupled-ODE models by incorporating geometrical-acoustics (GA) corrections for the model of decay within subrooms and the model of energy transfer between subrooms. Previous researchers developed prediction algorithms based on computational GA. Comparisons of predictions derived from beam-axis tracing with scale-model measurements indicate that systematic errors for coupled rooms result from earlier tail-correction procedures that assume constant quadratic growth of reflection density. A new algorithm is developed that uses ray tracing rather than tail correction in the late part and is shown to correct this error. At midfrequencies [MF (f >> f Sch, a ˜ lambda)], HF models are modified to account for wave effects at coupling apertures by including analytically or heuristically derived power transmission coefficients tau. This work improves upon prior SA models of this type by developing more accurate estimates of random-incidence tau. While the accuracy of the MF models is difficult to verify, scale-model measurements evidence the expected behavior. The Biot-Tolstoy-Medwin-Svensson (BTMS) time-domain edge-diffraction model is newly adapted to study transmission through apertures. Multiple-order BTMS scattering is theoretically and experimentally shown to be inaccurate due to the neglect of slope diffraction. At low frequencies (f ˜ f Sch), scale-model measurements have been qualitatively explained by application of

  10. The development and potential of acoustic radiation force impulse (ARFI) imaging for carotid artery plaque characterization.

    PubMed

    Allen, Jason D; Ham, Katherine L; Dumont, Douglas M; Sileshi, Bantayehu; Trahey, Gregg E; Dahl, Jeremy J

    2011-08-01

    Stroke is the third leading cause of death and long-term disability in the USA. Currently, surgical intervention decisions in asymptomatic patients are based upon the degree of carotid artery stenosis. While there is a clear benefit of endarterectomy for patients with severe (> 70%) stenosis, in those with high/moderate (50-69%) stenosis the evidence is less clear. Evidence suggests ischemic stroke is associated less with calcified and fibrous plaques than with those containing softer tissue, especially when accompanied by a thin fibrous cap. A reliable mechanism for the identification of individuals with atherosclerotic plaques which confer the highest risk for stroke is fundamental to the selection of patients for vascular interventions. Acoustic radiation force impulse (ARFI) imaging is a new ultrasonic-based imaging method that characterizes the mechanical properties of tissue by measuring displacement resulting from the application of acoustic radiation force. These displacements provide information about the local stiffness of tissue and can differentiate between soft and hard areas. Because arterial walls, soft tissue, atheromas, and calcifications have a wide range in their stiffness properties, they represent excellent candidates for ARFI imaging. We present information from early phantom experiments and excised human limb studies to in vivo carotid artery scans and provide evidence for the ability of ARFI to provide high-quality images which highlight mechanical differences in tissue stiffness not readily apparent in matched B-mode images. This allows ARFI to identify soft from hard plaques and differentiate characteristics associated with plaque vulnerability or stability. PMID:21447606

  11. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1994-01-01

    Quantum mechanical methods have been used to compute potential energy surfaces for chemical reactions. The reactions studied were among those believed to be important to the NASP and HSR programs and included the recombination of two H atoms with several different third bodies; the reactions in the thermal Zeldovich mechanism; the reactions of H atom with O2, N2, and NO; reactions involved in the thermal De-NO(x) process; and the reaction of CH(squared Pi) with N2 (leading to 'prompt NO'). These potential energy surfaces have been used to compute reaction rate constants and rates of unimolecular decomposition. An additional application was the calculation of transport properties of gases using a semiclassical approximation (and in the case of interactions involving hydrogen inclusion of quantum mechanical effects).

  12. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1990-01-01

    The objective was to obtain accurate potential energy surfaces (PES's) for a number of reactions which are important in the H/N/O combustion process. The interest in this is centered around the design of the SCRAM jet engine for the National Aerospace Plane (NASP), which was envisioned as an air-breathing hydrogen-burning vehicle capable of reaching velocities as large as Mach 25. Preliminary studies indicated that the supersonic flow in the combustor region of the scram jet engine required accurate reaction rate data for reactions in the H/N/O system, some of which was not readily available from experiment. The most important class of combustion reactions from the standpoint of the NASP project are radical recombinaton reactions, since these reactions result in most of the heat release in the combustion process. Theoretical characterizations of the potential energy surfaces for these reactions are presented and discussed.

  13. Potential Energy Curves of Hydrogen Fluoride

    NASA Technical Reports Server (NTRS)

    Fallon, Robert J.; Vanderslice, Joseph T.; Mason, Edward A.

    1960-01-01

    Potential energy curves for the X(sup 1)sigma+ and V(sup 1)sigma+ states of HF and DF have been calculated by the Rydberg-Klein-Rees method. The results calculated from the different sets of data for HF and DF are found to be in very good agreement. The theoretical results of Karo are compared to the experimental results obtained here.

  14. Energy Savings Potential of Radiative Cooling Technologies

    SciTech Connect

    Fernandez, Nicholas; Wang, Weimin; Alvine, Kyle J.; Katipamula, Srinivas

    2015-11-30

    Pacific Northwest National Laboratory (PNNL), with funding from the U.S. Department of Energy’s (DOE’s) Building Technologies Program (BTP), conducted a study to estimate, through simulation, the potential cooling energy savings that could be achieved through novel approaches to capturing free radiative cooling in buildings, particularly photonic ‘selective emittance’ materials. This report documents the results of that study.

  15. Energy balanced strategies for maximizing the lifetime of sparsely deployed underwater acoustic sensor networks.

    PubMed

    Luo, Hanjiang; Guo, Zhongwen; Wu, Kaishun; Hong, Feng; Feng, Yuan

    2009-01-01

    Underwater acoustic sensor networks (UWA-SNs) are envisioned to perform monitoring tasks over the large portion of the world covered by oceans. Due to economics and the large area of the ocean, UWA-SNs are mainly sparsely deployed networks nowadays. The limited battery resources is a big challenge for the deployment of such long-term sensor networks. Unbalanced battery energy consumption will lead to early energy depletion of nodes, which partitions the whole networks and impairs the integrity of the monitoring datasets or even results in the collapse of the entire networks. On the contrary, balanced energy dissipation of nodes can prolong the lifetime of such networks. In this paper, we focus on the energy balance dissipation problem of two types of sparsely deployed UWA-SNs: underwater moored monitoring systems and sparsely deployed two-dimensional UWA-SNs. We first analyze the reasons of unbalanced energy consumption in such networks, then we propose two energy balanced strategies to maximize the lifetime of networks both in shallow and deep water. Finally, we evaluate our methods by simulations and the results show that the two strategies can achieve balanced energy consumption per node while at the same time prolong the networks lifetime. PMID:22399970

  16. Convective Available Potential Energy of World Ocean

    NASA Astrophysics Data System (ADS)

    Su, Z.; Ingersoll, A. P.; Thompson, A. F.

    2012-12-01

    Here, for the first time, we propose the concept of Ocean Convective Available Potential Energy (OCAPE), which is the maximum kinetic energy (KE) per unit seawater mass achievable by ocean convection. OCAPE occurs through a different mechanism from atmospheric CAPE, and involves the interplay of temperature and salinity on the equation of state of seawater. The thermobaric effect, which arises because the thermal coefficient of expansion increases with depth, is an important ingredient of OCAPE. We develop an accurate algorithm to calculate the OCAPE for a given temperature and salinity profile. We then validate our calculation of OCAPE by comparing it with the conversion of OCAPE to KE in a 2-D numerical model. We propose that OCAPE is an important energy source of ocean deep convection and contributes to deep water formation. OCAPE, like Atmospheric CAPE, can help predict deep convection and may also provide a useful constraint for modelling deep convection in ocean GCMs. We plot the global distribution of OCAPE using data from the World Ocean Atlas 2009 (WOA09) and see many important features. These include large values of OCAPE in the Labrador, Greenland, Weddell and Mediterranean Seas, which are consistent with our present observations and understanding, but also identify some new features like the OCAPE pattern in the Antarctic Circumpolar Current (ACC). We propose that the diagnosis of OCAPE can improve our understanding of global patterns of ocean convection and deep water formation as well as ocean stratification, the meridional overturning circulation and mixed layer processes. The background of this work is briefly introduced as below. Open-ocean deep convection can significantly modify water properties both at the ocean surface and throughout the water column (Gordon 1982). Open-ocean convection is also an important mechanism for Ocean Deep Water formation and the transport of heat, freshwater and nutrient (Marshall and Schott 1999). Open

  17. Efficient Structure Resonance Energy Transfer from Microwaves to Confined Acoustic Vibrations in Viruses

    NASA Astrophysics Data System (ADS)

    Yang, Szu-Chi; Lin, Huan-Chun; Liu, Tzu-Ming; Lu, Jen-Tang; Hung, Wan-Ting; Huang, Yu-Ru; Tsai, Yi-Chun; Kao, Chuan-Liang; Chen, Shih-Yuan; Sun, Chi-Kuang

    2015-12-01

    Virus is known to resonate in the confined-acoustic dipolar mode with microwave of the same frequency. However this effect was not considered in previous virus-microwave interaction studies and microwave-based virus epidemic prevention. Here we show that this structure-resonant energy transfer effect from microwaves to virus can be efficient enough so that airborne virus was inactivated with reasonable microwave power density safe for the open public. We demonstrate this effect by measuring the residual viral infectivity of influenza A virus after illuminating microwaves with different frequencies and powers. We also established a theoretical model to estimate the microwaves power threshold for virus inactivation and good agreement with experiments was obtained. Such structure-resonant energy transfer induced inactivation is mainly through physically fracturing the virus structure, which was confirmed by real-time reverse transcription polymerase chain reaction. These results provide a pathway toward establishing a new epidemic prevention strategy in open public for airborne virus.

  18. RAPID COMMUNICATION: Traceability of acoustic emission measurements using energy calibration methods

    NASA Astrophysics Data System (ADS)

    Yan, T.; Jones, B. E.

    2000-11-01

    Passive acoustic emission (AE) methods are becoming useful tools for integrity assessment of structures, monitoring of industrial processes and machines, and materials characterization. Unfortunately, there are no measurement standards for estimating the absolute strength of the AE sources. The lack of standardization makes it very difficult to compare the results obtained in different laboratories or on different structures, and to obtain meaningful repeatability of measurements. Therefore, current methods only give a qualitative rather than quantitative indication of the change of state of structure or process. This communication outlines a way of calibrating AE transducer systems in situ using a pulsed-laser-generated thermoelastic AE energy source or a bouncing-ball-generated elastic impact AE energy source. The methods presented here should enable traceable measurement standards to be established for AE.

  19. The Wind Energy Potential of Iceland

    NASA Astrophysics Data System (ADS)

    Nawri, Nikolai; Nína Petersen, Guðrún; Bjornsson, Halldór; Hahmann, Andrea N.; Jónasson, Kristján; Bay Hasager, Charlotte; Clausen, Niels-Erik

    2014-05-01

    While Iceland has an abundant wind energy resource, its use for electrical power production has so far been limited. Electricity in Iceland is generated primarily from hydro- and geothermal sources, and adding wind energy has so far not been considered practical or even necessary. However, wind energy is becoming a more viable option, as opportunities for new hydro- or geothermal power installations become limited. In order to obtain an estimate of the wind energy potential of Iceland, a wind atlas has been developed as part of the joint Nordic project 'Improved Forecast of Wind, Waves and Icing' (IceWind). Downscaling simulations performed with the Weather Research and Forecasting (WRF) model were used to determine the large-scale wind energy potential of Iceland. Local wind speed distributions are represented by Weibull statistics. The shape parameter across Iceland varies between 1.2 and 3.6, with the lowest values indicative of near-exponential distributions at sheltered locations, and the highest values indicative of normal distributions at exposed locations in winter. Compared with summer, average power density in winter is increased throughout Iceland by a factor of 2.0 - 5.5. In any season, there are also considerable spatial differences in average wind power density. Relative to the average value within 10 km of the coast, power density across Iceland varies between 50 - 250%, excluding glaciers, or between 300 - 1500 W m-2 at 50 m above ground level in winter. At intermediate elevations of 500 - 1000 m above mean sea level, power density is independent of the distance to the coast. In addition to seasonal and spatial variability, differences in average wind speed and power density also exist for different wind directions. Along the coast in winter, power density of onshore winds is higher by 100 - 700 W m-2 than that of offshore winds. The regions with the highest average wind speeds are impractical for wind farms, due to the distances from road

  20. Potential energy surfaces of Polonium isotopes

    NASA Astrophysics Data System (ADS)

    Nerlo-Pomorska, B.; Pomorski, K.; Schmitt, C.; Bartel, J.

    2015-11-01

    The evolution of the potential energy landscape is analysed in detail for ten even-even polonium isotopes in the mass range 188\\lt A\\lt 220 as obtained within the macroscopic-microscopic approach, relying on the Lublin-Strasbourg drop model and the Yukawa-folded single-particle energies for calculating the microscopic shell and pairing corrections. A variant of the modified Funny-Hills nuclear shape parametrization is used to efficiently map possible fission paths. The approach explains the main features of the fragment partition as measured in low-energy fission along the polonium chain. The latter lies in a transitional region of the nuclear chart, and will be essential to consistently understand the evolution of fission properties from neutron-deficient mercury to heavy actinides. The ability of our method to predict fission observables over such an extended region looks promising.

  1. Contactless ultrasonic energy transfer for wireless systems: acoustic-piezoelectric structure interaction modeling and performance enhancement

    NASA Astrophysics Data System (ADS)

    Shahab, S.; Erturk, A.

    2014-12-01

    There are several applications of wireless electronic components with little or no ambient energy available to harvest, yet wireless battery charging for such systems is still of great interest. Example applications range from biomedical implants to sensors located in hazardous environments. Energy transfer based on the propagation of acoustic waves at ultrasonic frequencies is a recently explored alternative that offers increased transmitter-receiver distance, reduced loss and the elimination of electromagnetic fields. As this research area receives growing attention, there is an increased need for fully coupled model development to quantify the energy transfer characteristics, with a focus on the transmitter, receiver, medium, geometric and material parameters. We present multiphysics modeling and case studies of the contactless ultrasonic energy transfer for wireless electronic components submerged in fluid. The source is a pulsating sphere, and the receiver is a piezoelectric bar operating in the 33-mode of piezoelectricity with a fundamental resonance frequency above the audible frequency range. The goal is to quantify the electrical power delivered to the load (connected to the receiver) in terms of the source strength. Both the analytical and finite element models have been developed for the resulting acoustic-piezoelectric structure interaction problem. Resistive and resistive-inductive electrical loading cases are presented, and optimality conditions are discussed. Broadband power transfer is achieved by optimal resistive-reactive load tuning for performance enhancement and frequency-wise robustness. Significant enhancement of the power output is reported due to the use of a hard piezoelectric receiver (PZT-8) instead of a soft counterpart (PZT-5H) as a result of reduced material damping. The analytical multiphysics modeling approach given in this work can be used to predict and optimize the coupled system dynamics with very good accuracy and dramatically

  2. Investigation of acoustic cavitation energy in a large-scale sonoreactor.

    PubMed

    Son, Younggyu; Lim, Myunghee; Khim, Jeehyeong

    2009-04-01

    Acoustic cavitation energy distributions were investigated for various frequencies such as 35, 72, 110 and 170 kHz in a large-scale sonoreactor. The energy analyses were conducted in three-dimensions and the highest and most stable cavitation energy distribution was obtained not in 35 kHz but in 72 kHz. However, the half-cavitation-energy distance was larger in the case of 35 kHz ultrasound than in the case of 72 kHz, demonstrating that cavitation energy for one cycle was higher for a lower frequency. This discrepancy was due to the large surface area of the cavitation-energy-meter probe. In addition, 110 and 170 kHz ultrasound showed a very low and poor cavitation energy distribution. Therefore larger input power was required to optimize the use of higher frequency ultrasound in the sonoreactor with long-irradiation distance. The relationship between cavitation energy and sonochemical efficiency using potassium iodide (KI) dosimetry was best fitted quadratically. From 7.77 x 10(-10) to 4.42 x 10(-9)mol/J of sonochemical efficiency was evaluated for the cavitation energy from 31.76 to 103. 67 W. In addition, the cavitation energy attenuation was estimated under the assumption that cavitation energy measured in this study would be equivalent to sound intensity, resulting in 0.10, 0.18 and 2.44 m(-1) of the attenuation coefficient (alpha) for 35, 72 and 110 kHz, respectively. Furthermore, alpha/(frequency)(2) was not constant, as some previous studies have suggested. PMID:19144557

  3. An experimentally validated contactless acoustic energy transfer model with resistive-reactive electrical loading

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    This paper investigates analytical modeling and experimental validation of Ultrasonic Acoustic Energy Transfer (UAET) for low-power electricity transfer to exploit in wireless applications ranging from medical implants to underwater sensor systems. A piezoelectric receiver bar is excited by incident acoustic waves originating from a source of known strength located at a specific distance from the receiver. The receiver is a free-free piezoelectric cylinder operating in the 33- mode of piezoelectricity with a fundamental resonance frequency above the audible frequency range. In order to extract the electrical power output, the piezoelectric receiver bar is shunted to a generalized resistive-reactive circuit. The goal is to quantify the electrical power delivered to the load (connected to the receiver) in terms of the source strength. Experimental validations are presented along with parameter optimization studies. Sensitivity of the electrical power output to the excitation frequency in the neighborhood of the receiver's underwater resonance frequency, source-to-receiver distance, and source-strength level are reported. Resistive and resistive-reactive electrical loading cases are discussed for performance enhancement and frequency-wise robustness. Simulations and experiments reveal that the presented multiphysics analytical model for UAET can be used to predict the coupled system dynamics with very good accuracy.

  4. Controlled and in situ target strengths of the jumbo squid Dosidicus gigas and identification of potential acoustic scattering sources.

    PubMed

    Benoit-Bird, Kelly J; Gilly, William F; Au, Whitlow W L; Mate, Bruce

    2008-03-01

    This study presents the first target strength measurements of Dosidicus gigas, a large squid that is a key predator, a significant prey, and the target of an important fishery. Target strength of live, tethered squid was related to mantle length with values standardized to the length squared of -62.0, -67.4, -67.9, and -67.6 dB at 38, 70, 120, and 200 kHz, respectively. There were relatively small differences in target strength between dorsal and anterior aspects and none between live and freshly dead squid. Potential scattering mechanisms in squid have been long debated. Here, the reproductive organs had little effect on squid target strength. These data support the hypothesis that the pen may be an important source of squid acoustic scattering. The beak, eyes, and arms, probably via the sucker rings, also play a role in acoustic scattering though their effects were small and frequency specific. An unexpected source of scattering was the cranium of the squid which provided a target strength nearly as high as that of the entire squid though the mechanism remains unclear. Our in situ measurements of the target strength of free-swimming squid support the use of the values presented here in D. gigas assessment studies. PMID:18345820

  5. 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.

  6. Positive-energy D-bar method for acoustic tomography: a computational study

    NASA Astrophysics Data System (ADS)

    de Hoop, M. V.; Lassas, M.; Santacesaria, M.; Siltanen, S.; Tamminen, J. P.

    2016-02-01

    A new computational method for reconstructing a potential from the Dirichlet-to-Neumann (DN) map at positive energy is developed. The method is based on D-bar techniques and it works in absence of exceptional points—in particular, if the potential is small enough compared to the energy. Numerical tests reveal exceptional points for perturbed, radial potentials. Reconstructions for several potentials are computed using simulated DN maps with and without added noise. The new reconstruction method is shown to work well for energy values between 10-5 and 5, smaller values giving better results.

  7. 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.

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

    DOEpatents

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

    1998-01-01

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

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

    DOEpatents

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

    1998-05-19

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

  10. The wind energy potential of western Greece

    SciTech Connect

    Katsoulis, B.D.; Metaxas, D.A. )

    1992-12-01

    In this study wind data were used to determine the monthly and annual variations of the wind at 13 meterological stations in western Greece. An analysis of the available wind data for the Ionian Sea islands and the western coasts of Greece is carried out to ascertain its potential for wind energy development. The effect of the limited number of daily observations available on the accuracy of the mean wind speed and annual wind energy estimates is ascertained. The wind speed and direction distributions are represented with Weibull functions. Besides, a mass-consistent numerical mesoscale model was used to give an overview of the wind prospecting and siting problem, and an example of its use for Corfu (Kerkira), an island in the Ionian Sea, is given. The comparison of the accuracy of the stimulation results versus measured wind at an available site is quite encouraging even though it cannot be conclusive since only one station is available.

  11. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.; Levin, Eugene

    1993-01-01

    A new global potential energy surface (PES) is being generated for O(P-3) + H2 yields OH + H. This surface is being fit using the rotated Morse oscillator method, which was used to fit the previous POL-CI surface. The new surface is expected to be more accurate and also includes a much more complete sampling of bent geometries. A new study has been undertaken of the reaction N + O2 yields NO + O. The new studies have focused on the region of the surface near a possible minimum corresponding to the peroxy form of NOO. A large portion of the PES for this second reaction has been mapped out. Since state to state cross sections for the reaction are important in the chemistry of high temperature air, these studies will probably be extended to permit generation of a new global potential for reaction.

  12. Theoretical studies of potential energy surfaces.

    SciTech Connect

    Harding, L. B.

    2006-01-01

    The goal of this program is to calculate accurate potential energy surfaces for both reactive and nonreactive systems. To do this the electronic Schroedinger equation must be solved. Our approach starts with multiconfiguration self-consistent field (MCSCF) reference wave functions. These reference wavefunctions are designed to be sufficiently flexible to accurately describe changes in electronic structure over a broad range of geometries. Dynamical electron correlation effects are included via multireference, singles and doubles configuration interaction (MRCI) calculations. With this approach, we are able to provide chemically useful predictions of the energetics for many systems. A second aspect of this program is the development of techniques to fit multi-dimensional potential surfaces to convenient, global, analytic functions that can then be used in dynamics calculations.

  13. Theoretical studies of potential energy surfaces

    SciTech Connect

    Harding, L.B.

    1993-12-01

    The goal of this program is to calculate accurate potential energy surfaces (PES) for both reactive and nonreactive systems. To do this the electronic Schrodinger equation must be solved. Our approach to this problem starts with multiconfiguration self-consistent field (MCSCF) reference wavefunctions. These reference wavefunctions are designed to be sufficiently flexible to accurately describe changes in electronic structure over a broad range of geometries. Electron correlation effects are included via multireference, singles and doubles configuration interaction (MRSDCI) calculations. With this approach, the authors are able to provide useful predictions of the energetics for a broad range of systems.

  14. Measuring acoustic energy density in microchannel acoustophoresis using a simple and rapid light-intensity method.

    PubMed

    Barnkob, Rune; Iranmanesh, Ida; Wiklund, Martin; Bruus, Henrik

    2012-07-01

    We present a simple and rapid method for measuring the acoustic energy density in microchannel acoustophoresis based on light-intensity measurements of a suspension of particles. The method relies on the assumption that each particle in the suspension undergoes single-particle acoustophoresis. It is validated by the single-particle tracking method, and we show by proper re-scaling that the re-scaled light intensity plotted versus re-scaled time falls on a universal curve. The method allows for analysis of moderate-resolution images in the concentration range encountered in typical experiments, and it is an attractive alternative to particle tracking and particle image velocimetry for quantifying acoustophoretic performance in microchannels. PMID:22522812

  15. Vibro-acoustic modelling of aircraft double-walls with structural links using Statistical Energy Analysis

    NASA Astrophysics Data System (ADS)

    Campolina, Bruno L.

    The prediction of aircraft interior noise involves the vibroacoustic modelling of the fuselage with noise control treatments. This structure is composed of a stiffened metallic or composite panel, lined with a thermal and acoustic insulation layer (glass wool), and structurally connected via vibration isolators to a commercial lining panel (trim). The goal of this work aims at tailoring the noise control treatments taking design constraints such as weight and space optimization into account. For this purpose, a representative aircraft double-wall is modelled using the Statistical Energy Analysis (SEA) method. Laboratory excitations such as diffuse acoustic field and point force are addressed and trends are derived for applications under in-flight conditions, considering turbulent boundary layer excitation. The effect of the porous layer compression is firstly addressed. In aeronautical applications, compression can result from the installation of equipment and cables. It is studied analytically and experimentally, using a single panel and a fibrous uniformly compressed over 100% of its surface. When compression increases, a degradation of the transmission loss up to 5 dB for a 50% compression of the porous thickness is observed mainly in the mid-frequency range (around 800 Hz). However, for realistic cases, the effect should be reduced since the compression rate is lower and compression occurs locally. Then the transmission through structural connections between panels is addressed using a four-pole approach that links the force-velocity pair at each side of the connection. The modelling integrates experimental dynamic stiffness of isolators, derived using an adapted test rig. The structural transmission is then experimentally validated and included in the double-wall SEA model as an equivalent coupling loss factor (CLF) between panels. The tested structures being flat, only axial transmission is addressed. Finally, the dominant sound transmission paths are

  16. 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

  17. 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

  18. Potential efficacy of early treatment of acute acoustic trauma with steroids and piracetam after gunshot noise.

    PubMed

    Psillas, George; Pavlidis, Pavlos; Karvelis, Ioannis; Kekes, George; Vital, Victor; Constantinidis, John

    2008-12-01

    The purpose of this randomized study was to evaluate the early effect of the treatment of acute acoustic trauma (AAT) with steroids and piracetam in a sample of 52 young soldiers who were exposed to intense gunfire noise (G3 rifle). These patients were divided into three groups: (1) group A (20 patients) in which the treatment began within the first hour after the AAT, (2) group B (17 patients) in which the treatment started more than 1 h later and less than 16 h after the AAT and (3) group C (15 patients) in which the treatment began after 24 h or more. One month after the treatment onset, 36 (69%) patients of all the groups showed hearing improvement (complete-partial recovery) in the pure tone audiometry. The greater number of patients who showed complete recovery after AAT was noted in group A (65%) compared to group B (23.5%) and C (13.3%). Moreover, in group A, in the final audiogram, the averaged hearing threshold was statistically better (P < 0.001) than that of groups B and C. In spite of the lack of control group, our data demonstrated the possible effectiveness of the immediate onset of treatment of AAT. PMID:18463885

  19. Assessment of wind energy potential in Poland

    NASA Astrophysics Data System (ADS)

    Starosta, Katarzyna; Linkowska, Joanna; Mazur, Andrzej

    2014-05-01

    The aim of the presentation is to show the suitability of using numerical model wind speed forecasts for the wind power industry applications in Poland. In accordance with the guidelines of the European Union, the consumption of wind energy in Poland is rapidly increasing. According to the report of Energy Regulatory Office from 30 March 2013, the installed capacity of wind power in Poland was 2807MW from 765 wind power stations. Wind energy is strongly dependent on the meteorological conditions. Based on the climatological wind speed data, potential energy zones within the area of Poland have been developed (H. Lorenc). They are the first criterion for assessing the location of the wind farm. However, for exact monitoring of a given wind farm location the prognostic data from numerical model forecasts are necessary. For the practical interpretation and further post-processing, the verification of the model data is very important. Polish Institute Meteorology and Water Management - National Research Institute (IMWM-NRI) runs an operational model COSMO (Consortium for Small-scale Modelling, version 4.8) using two nested domains at horizontal resolutions of 7 km and 2.8 km. The model produces 36 hour and 78 hour forecasts from 00 UTC, for 2.8 km and 7 km domain resolutions respectively. Numerical forecasts were compared with the observation of 60 SYNOP and 3 TEMP stations in Poland, using VERSUS2 (Unified System Verification Survey 2) and R package. For every zone the set of statistical indices (ME, MAE, RMSE) was calculated. Forecast errors for aerological profiles are shown for Polish TEMP stations at Wrocław, Legionowo and Łeba. The current studies are connected with a topic of the COST ES1002 WIRE-Weather Intelligence for Renewable Energies.

  20. Energy potential of sugarcane and sweet sorghum

    SciTech Connect

    Elawad, S.H.; Gascho, G.J.; Shih, S.F.

    1980-01-01

    The potential of sugarcane and sweet sorghum as raw materials for the production of ethanol and petrochemical substitutes is discussed. Both crops belong to the grass family and are classified as C/sub 4/ malateformers which have the highest rate of photosynthesis among terrestrial plants. Large amounts of biomass are required to supply a significant fraction of US energy consumption. Biomass production could be substantially increased by including tops and leaves, adopting narrow row spacing and improving cultural practices. This presents challenges for cultivating, harvesting, and hauling the biomass to processing centers. Large plants and heavy capital investment are essential for energy production. Ethanol and ammonia are the most promising candidates of a biomass program. If sugarcane were to be used for biomass production, breeding programs should be directed for more fermentable sugars and fiber. Energy research on sweet sorghum should be done with syrup varieties. Sweet sorghum needs to be incorporated with other crops because of its short growing season. The disposal of stillage from an extensive ethanol industry may pose environmental problems.

  1. Acoustic neuroma: potential risk factors and audiometric surveillance in the aluminium industry

    PubMed Central

    Taiwo, Oyebode; Galusha, Deron; Tessier-Sherman, Baylah; Kirsche, Sharon; Cantley, Linda; Slade, Martin D; Cullen, Mark R; Donoghue, A Michael

    2014-01-01

    Objectives To look for an association between acoustic neuroma (AN) and participation in a hearing conservation programme (HCP) and also for an association between AN and possible occupational risk factors in the aluminium industry. Methods We conducted a case–control analysis of a population of US aluminium production workers in 8 smelters and 43 other plants. Using insurance claims data, 97 cases of AN were identified between 1996 and 2009. Each was matched with four controls. Covariates included participation in a HCP, working in an aluminium smelter, working in an electrical job and hearing loss. Results In the bivariate analyses, covariates associated with AN were participation in the HCP (OR=1.72; 95% CI 1.09 to 2.69) and smelter work (OR=1.88; 95% CI 1.06 to 3.36). Electrical work was not significant (OR=1.60; 95% CI 0.65 to 3.94). Owing to high participation in the HCP in smelters, multivariate subanalyses were required. In the multivariate analyses, participation in the HCP was the only statistically significant risk factor for AN. In the multivariate analysis restricted to employees not working in a smelter, the OR was 1.81 (95% CI 1.04 to 3.17). Hearing loss, an indirect measure of in-ear noise dose, was not predictive of AN. Conclusions Our results suggest the incidental detection of previously undiagnosed tumours in workers who participated in the company-sponsored HCP. The increased medical surveillance among this population of workers most likely introduced detection bias, leading to the identification of AN cases that would have otherwise remained undetected. PMID:25015928

  2. Induced Seismicity Potential of Energy Technologies

    NASA Astrophysics Data System (ADS)

    Hitzman, Murray

    2013-03-01

    Earthquakes attributable to human activities-``induced seismic events''-have received heightened public attention in the United States over the past several years. Upon request from the U.S. Congress and the Department of Energy, the National Research Council was asked to assemble a committee of experts to examine the scale, scope, and consequences of seismicity induced during fluid injection and withdrawal associated with geothermal energy development, oil and gas development, and carbon capture and storage (CCS). The committee's report, publicly released in June 2012, indicates that induced seismicity associated with fluid injection or withdrawal is caused in most cases by change in pore fluid pressure and/or change in stress in the subsurface in the presence of faults with specific properties and orientations and a critical state of stress in the rocks. The factor that appears to have the most direct consequence in regard to induced seismicity is the net fluid balance (total balance of fluid introduced into or removed from the subsurface). Energy technology projects that are designed to maintain a balance between the amount of fluid being injected and withdrawn, such as most oil and gas development projects, appear to produce fewer seismic events than projects that do not maintain fluid balance. Major findings from the study include: (1) as presently implemented, the process of hydraulic fracturing for shale gas recovery does not pose a high risk for inducing felt seismic events; (2) injection for disposal of waste water derived from energy technologies does pose some risk for induced seismicity, but very few events have been documented over the past several decades relative to the large number of disposal wells in operation; and (3) CCS, due to the large net volumes of injected fluids suggested for future large-scale carbon storage projects, may have potential for inducing larger seismic events.

  3. Model-independent dark energy equation of state from unanchored baryon acoustic oscillations

    NASA Astrophysics Data System (ADS)

    Evslin, Jarah

    2016-09-01

    Ratios of line of sight baryon acoustic oscillation (BAO) peaks at two redshifts only depend upon the average dark energy equation of states between those redshifts, as the dependence on anchors such as the BAO scale or the Hubble constant is canceled in a ratio. As a result, BAO ratios provide a probe of dark energy which is independent of both the cosmic distance ladder and the early evolution of universe. In this note, we use ratios to demonstrate that the known tension between the Lyman alpha forest BAO measurement and other probes arises entirely from recent (0.57 < z < 2.34) cosmological expansion. Using ratios of the line of sight Lyman alpha forest and BOSS CMASS BAO scales, we show that there is already more than 3 σ tension with the standard ΛCDM cosmological model which implies that either (i) The BOSS Lyman alpha forest measurement of the Hubble parameter was too low as a result of a statistical fluctuation or systematic error or else (ii) the dark energy equation of state falls steeply at high redshift.

  4. Certification and the potential energy landscape

    SciTech Connect

    Mehta, Dhagash; Hauenstein, Jonathan D.; Wales, David J.

    2014-06-14

    Typically, there is no guarantee that a numerical approximation obtained using standard nonlinear equation solvers is indeed an actual solution, meaning that it lies in the quadratic convergence basin. Instead, it may lie only in the linear convergence basin, or even in a chaotic region, and hence not converge to the corresponding stationary point when further optimization is attempted. In some cases, these non-solutions could be misleading. Proving that a numerical approximation will quadratically converge to a stationary point is termed certification. In this report, we provide details of how Smale's α-theory can be used to certify numerically obtained stationary points of a potential energy landscape, providing a mathematical proof that the numerical approximation does indeed correspond to an actual stationary point, independent of the precision employed.

  5. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1988-01-01

    The minimum energy path for the addition of a hydrogen atom to N2 is characterized in CASSCF/CCI calculations using the (4s3p2d1f/3s2p1d) basis set, with additional single point calculations at the stationary points of the potential energy surface using the (5s4p3d2f/4s3p2d) basis set. These calculations represent the most extensive set of ab initio calculations completed to date, yielding a zero point corrected barrier for HN2 dissociation of approx. 8.5 kcal mol/1. The lifetime of the HN2 species is estimated from the calculated geometries and energetics using both conventional Transition State Theory and a method which utilizes an Eckart barrier to compute one dimensional quantum mechanical tunneling effects. It is concluded that the lifetime of the HN2 species is very short, greatly limiting its role in both termolecular recombination reactions and combustion processes.

  6. The Wind Energy Potential of Kurdistan, Iran.

    PubMed

    Arefi, Farzad; Moshtagh, Jamal; Moradi, Mohammad

    2014-01-01

    In the current work by using statistical methods and available software, the wind energy assessment of prone regions for installation of wind turbines in, Qorveh, has been investigated. Information was obtained from weather stations of Baneh, Bijar, Zarina, Saqez, Sanandaj, Qorveh, and Marivan. The monthly average and maximum of wind speed were investigated between the years 2000-2010 and the related curves were drawn. The Golobad curve (direction and percentage of dominant wind and calm wind as monthly rate) between the years 1997-2000 was analyzed and drawn with plot software. The ten-minute speed (at 10, 30, and 60 m height) and direction (at 37.5 and 10 m height) wind data were collected from weather stations of Iranian new energy organization. The wind speed distribution during one year was evaluated by using Weibull probability density function (two-parametrical), and the Weibull curve histograms were drawn by MATLAB software. According to the average wind speed of stations and technical specifications of the types of turbines, the suitable wind turbine for the station was selected. Finally, the Divandareh and Qorveh sites with favorable potential were considered for installation of wind turbines and construction of wind farms. PMID:27355042

  7. The Wind Energy Potential of Kurdistan, Iran

    PubMed Central

    Arefi, Farzad; Moshtagh, Jamal; Moradi, Mohammad

    2014-01-01

    In the current work by using statistical methods and available software, the wind energy assessment of prone regions for installation of wind turbines in, Qorveh, has been investigated. Information was obtained from weather stations of Baneh, Bijar, Zarina, Saqez, Sanandaj, Qorveh, and Marivan. The monthly average and maximum of wind speed were investigated between the years 2000–2010 and the related curves were drawn. The Golobad curve (direction and percentage of dominant wind and calm wind as monthly rate) between the years 1997–2000 was analyzed and drawn with plot software. The ten-minute speed (at 10, 30, and 60 m height) and direction (at 37.5 and 10 m height) wind data were collected from weather stations of Iranian new energy organization. The wind speed distribution during one year was evaluated by using Weibull probability density function (two-parametrical), and the Weibull curve histograms were drawn by MATLAB software. According to the average wind speed of stations and technical specifications of the types of turbines, the suitable wind turbine for the station was selected. Finally, the Divandareh and Qorveh sites with favorable potential were considered for installation of wind turbines and construction of wind farms. PMID:27355042

  8. Energy resource potential of natural gas hydrates

    USGS Publications Warehouse

    Collett, T.S.

    2002-01-01

    The discovery of large gas hydrate accumulations in terrestrial permafrost regions of the Arctic and beneath the sea along the outer continental margins of the world's oceans has heightened interest in gas hydrates as a possible energy resource. However, significant to potentially insurmountable technical issues must be resolved before gas hydrates can be considered a viable option for affordable supplies of natural gas. The combined information from Arctic gas hydrate studies shows that, in permafrost regions, gas hydrates may exist at subsurface depths ranging from about 130 to 2000 m. The presence of gas hydrates in offshore continental margins has been inferred mainly from anomalous seismic reflectors, known as bottom-simulating reflectors, that have been mapped at depths below the sea floor ranging from about 100 to 1100 m. Current estimates of the amount of gas in the world's marine and permafrost gas hydrate accumulations are in rough accord at about 20,000 trillion m3. Disagreements over fundamental issues such as the volume of gas stored within delineated gas hydrate accumulations and the concentration of gas hydrates within hydrate-bearing strata have demonstrated that we know little about gas hydrates. Recently, however, several countries, including Japan, India, and the United States, have launched ambitious national projects to further examine the resource potential of gas hydrates. These projects may help answer key questions dealing with the properties of gas hydrate reservoirs, the design of production systems, and, most important, the costs and economics of gas hydrate production.

  9. Molecular Multipole Potential Energy Functions for Water.

    PubMed

    Tan, Ming-Liang; Tran, Kelly N; Pickard, Frank C; Simmonett, Andrew C; Brooks, Bernard R; Ichiye, Toshiko

    2016-03-01

    Water is the most common liquid on this planet, with many unique properties that make it essential for life as we know it. These properties must arise from features in the charge distribution of a water molecule, so it is essential to capture these features in potential energy functions for water to reproduce its liquid state properties in computer simulations. Recently, models that utilize a multipole expansion located on a single site in the water molecule, or "molecular multipole models", have been shown to rival and even surpass site models with up to five sites in reproducing both the electrostatic potential around a molecule and a variety of liquid state properties in simulations. However, despite decades of work using multipoles, confusion still remains about how to truncate the multipole expansions efficiently and accurately. This is particularly important when using molecular multipole expansions to describe water molecules in the liquid state, where the short-range interactions must be accurate, because the higher order multipoles of a water molecule are large. Here, truncation schemes designed for a recent efficient algorithm for multipoles in molecular dynamics simulations are assessed for how well they reproduce results for a simple three-site model of water when the multipole moments and Lennard-Jones parameters of that model are used. In addition, the multipole analysis indicates that site models that do not account for out-of-plane electron density overestimate the stability of a non-hydrogen-bonded conformation, leading to serious consequences for the simulated liquid. PMID:26562223

  10. 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.

  11. 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

  12. 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.

  13. Search for acoustic signals from ultrahigh energy neutrinos in 1500 km{sup 3} of sea water

    SciTech Connect

    Kurahashi, Naoko; Gratta, Giorgio; Vandenbroucke, Justin

    2010-10-01

    An underwater acoustic sensor array spanning {approx}1500 km{sup 3} is used to search for cosmic-ray neutrinos of ultrahigh energies ( E{sub {nu}>}10{sup 18} eV). Approximately 328 million triggers accumulated over an integrated 130 days of data taking are analyzed. The sensitivity of the experiment is determined from a Monte Carlo simulation of the array using recorded noise conditions and expected waveforms. Two events are found to have properties compatible with showers in the energy range 10{sup 24} eVenergy neutrinos using the acoustic technique.

  14. Efficient Structure Resonance Energy Transfer from Microwaves to Confined Acoustic Vibrations in Viruses

    PubMed Central

    Yang, Szu-Chi; Lin, Huan-Chun; Liu, Tzu-Ming; Lu, Jen-Tang; Hung, Wan-Ting; Huang, Yu-Ru; Tsai, Yi-Chun; Kao, Chuan-Liang; Chen, Shih-Yuan; Sun, Chi-Kuang

    2015-01-01

    Virus is known to resonate in the confined-acoustic dipolar mode with microwave of the same frequency. However this effect was not considered in previous virus-microwave interaction studies and microwave-based virus epidemic prevention. Here we show that this structure-resonant energy transfer effect from microwaves to virus can be efficient enough so that airborne virus was inactivated with reasonable microwave power density safe for the open public. We demonstrate this effect by measuring the residual viral infectivity of influenza A virus after illuminating microwaves with different frequencies and powers. We also established a theoretical model to estimate the microwaves power threshold for virus inactivation and good agreement with experiments was obtained. Such structure-resonant energy transfer induced inactivation is mainly through physically fracturing the virus structure, which was confirmed by real-time reverse transcription polymerase chain reaction. These results provide a pathway toward establishing a new epidemic prevention strategy in open public for airborne virus. PMID:26647655

  15. High-Efficiency Photovoltaic Energy Conversion using Surface Acoustic Waves in Piezoelectric Semiconductors

    NASA Astrophysics Data System (ADS)

    Yakovenko, Victor

    2010-03-01

    We propose a radically new design for photovoltaic energy conversion using surface acoustic waves (SAWs) in piezoelectric semiconductors. The periodically modulated electric field from SAW spatially separates photogenerated electrons and holes to the maxima and minima of SAW, thus preventing their recombination. The segregated electrons and holes are transported by the moving SAW to the collecting electrodes of two types, which produce dc electric output. Recent experiments [1] using SAWs in GaAs have demonstrated the photon to current conversion efficiency of 85%. These experiments were designed for photon counting, but we propose to adapt these techniques for highly efficient photovoltaic energy conversion. The advantages are that the electron-hole segregation takes place in the whole volume where SAW is present, and the electrons and holes are transported in the organized, collective manner at high speed, as opposed to random diffusion in conventional devices.[4pt] [1] S. J. Jiao, P. D. Batista, K. Biermann, R. Hey, and P. V. Santos, J. Appl. Phys. 106, 053708 (2009).

  16. Efficient Structure Resonance Energy Transfer from Microwaves to Confined Acoustic Vibrations in Viruses.

    PubMed

    Yang, Szu-Chi; Lin, Huan-Chun; Liu, Tzu-Ming; Lu, Jen-Tang; Hung, Wan-Ting; Huang, Yu-Ru; Tsai, Yi-Chun; Kao, Chuan-Liang; Chen, Shih-Yuan; Sun, Chi-Kuang

    2015-01-01

    Virus is known to resonate in the confined-acoustic dipolar mode with microwave of the same frequency. However this effect was not considered in previous virus-microwave interaction studies and microwave-based virus epidemic prevention. Here we show that this structure-resonant energy transfer effect from microwaves to virus can be efficient enough so that airborne virus was inactivated with reasonable microwave power density safe for the open public. We demonstrate this effect by measuring the residual viral infectivity of influenza A virus after illuminating microwaves with different frequencies and powers. We also established a theoretical model to estimate the microwaves power threshold for virus inactivation and good agreement with experiments was obtained. Such structure-resonant energy transfer induced inactivation is mainly through physically fracturing the virus structure, which was confirmed by real-time reverse transcription polymerase chain reaction. These results provide a pathway toward establishing a new epidemic prevention strategy in open public for airborne virus. PMID:26647655

  17. An ab initio method for locating potential energy minima

    SciTech Connect

    Bock, Nicolas; Peery, Travis; Venneri, Giulia; Chisolm, Eric; Wallace, Duane; Lizarraga, Raquel; Holmstrom, Erik

    2009-01-01

    We study the potential energy landscape underlying the motion of monatomic liquids by quenching from random initial configurations (stochastic configurations) to the nearest local minimum of the potential energy. We show that this procedure reveals the underlying potential energy surface directly. This is in contrast to the common technique of quenching from a molecular dynamics trajectory which does not allow a direct view of the underlying potential energy surface, but needs to be corrected for thermodynamic weighting factors.

  18. ASSESSMENT OF ENERGY RECOVERY POTENTIAL OF INDUSTRIAL COMBUSTION EQUIPMENT

    EPA Science Inventory

    An assessment was conducted to evaluate the waste heat content and energy recovery potential of flue gases from 30 industrial combustion devices. Pollution controls on nine of the devices were evaluated to estimate energy requirements and particulate reduction; energy requirement...

  19. Review of remote-sensor potential for wind-energy studies

    SciTech Connect

    Hooke, W.H.

    1981-03-01

    This report evaluates a number of remote-sensing systems such as radars, lidars, and acoustic echo sounders which are potential alternatives to the cup- and propeller anemometers routinely used in wind energy siting. The high costs and demanding operational requirements of these sensors currently preclude their use in the early stages of a multi-phase wind energy siting strategy such as that recently articulated by Hiester and Pennell (1981). Instead, these systems can be used most effectively in the lattermost stages of the siting process - what Hiester and Pennell (1981) refer to as the site development phase, necessary only for the siting of large wind-energy conversion systems (WECS) or WECS clusters. Even for this particular application only four techniques appear to be operational now; that is, if used properly, these techniques should provide the data sets currently considered adequate for wind-energy siting purposes. They are, in rough order of increasing expense and operating demands: optical transverse wind sensors; acoustic Doppler sounders; time-of-flight and continuous wave (CW) Doppler lidar; and frequency-modulated, continuous wave (FM-CW) Doppler radar.

  20. Transportation Energy Use and Conservation Potential

    ERIC Educational Resources Information Center

    Hirst, Eric

    1973-01-01

    Analyzes transportation energy consumption and energy intensiveness for inter-city freight and passenger traffic and urban passenger traffic with the definition of energy intensiveness as Btu per ton-mile or per passenger-mile. Indicates that public education is one of three ways to achieve the goals of energy conservation. (CC)

  1. Determination of Multidimensional Intermolecular Potential Energy Surfaces

    NASA Astrophysics Data System (ADS)

    Cohen, Ronald Carl

    High resolution spectroscopy of the low frequency van der Waals vibrations (also referred to as Vibration -Rotation-Tunneling (VRT) spectroscopy) in weakly bound complexes provides the means to probe intermolecular forces with unprecedented detail and precision. We present an overview of the experimental information on intermolecular forces and intermolecular dynamics which has been obtained by far infrared VRT spectroscopy of 18 complexes. We then turn to a detailed examination of the Ar-H_2O complex, a simple prototype for the study of intermolecular forces. The measurement and analysis of 9 VRT bands is described. These data are first used to obtain a qualitative description of the intermolecular potential energy surface (IPS). A new simple and efficient method for calculating the eigenvalues of the multidimensional intermolecular dynamics on the IPS has been developed. This algorithm (an adaptation of the Collocation Method) was then used in a direct fit to obtain an accurate and detailed description of the intermolecular forces acting within the Ar-H_2O complex.

  2. Model-independent Evidence for Dark Energy Evolution from Baryon Acoustic Oscillations

    NASA Astrophysics Data System (ADS)

    Sahni, V.; Shafieloo, A.; Starobinsky, A. A.

    2014-10-01

    Baryon acoustic oscillations (BAOs) allow us to determine the expansion history of the universe, thereby shedding light on the nature of dark energy. Recent observations of BAOs in the Sloan Digital Sky Survey (SDSS) DR9 and DR11 have provided us with statistically independent measurements of H(z) at redshifts of 0.57 and 2.34, respectively. We show that these measurements can be used to test the cosmological constant hypothesis in a model-independent manner by means of an improved version of the Om diagnostic. Our results indicate that the SDSS DR11 measurement of H(z) = 222 ± 7 km s-1 Mpc-1 at z = 2.34, when taken in tandem with measurements of H(z) at lower redshifts, imply considerable tension with the standard ΛCDM model. Our estimation of the new diagnostic Omh 2 from SDSS DR9 and DR11 data, namely, Omh 2 ≈ 0.122 ± 0.01, which is equivalent to Ω0m h 2 for the spatially flat ΛCDM model, is in tension with the value Ω0m h 2 = 0.1426 ± 0.0025 determined for ΛCDM from Planck+WP. This tension is alleviated in models in which the cosmological constant was dynamically screened (compensated) in the past. Such evolving dark energy models display a pole in the effective equation of state of dark energy at high redshifts, which emerges as a smoking gun test for these theories.

  3. MODEL-INDEPENDENT EVIDENCE FOR DARK ENERGY EVOLUTION FROM BARYON ACOUSTIC OSCILLATIONS

    SciTech Connect

    Sahni, V.; Shafieloo, A.; Starobinsky, A. A. E-mail: arman@apctp.org

    2014-10-01

    Baryon acoustic oscillations (BAOs) allow us to determine the expansion history of the universe, thereby shedding light on the nature of dark energy. Recent observations of BAOs in the Sloan Digital Sky Survey (SDSS) DR9 and DR11 have provided us with statistically independent measurements of H(z) at redshifts of 0.57 and 2.34, respectively. We show that these measurements can be used to test the cosmological constant hypothesis in a model-independent manner by means of an improved version of the Om diagnostic. Our results indicate that the SDSS DR11 measurement of H(z) = 222 ± 7 km s{sup –1} Mpc{sup –1} at z = 2.34, when taken in tandem with measurements of H(z) at lower redshifts, imply considerable tension with the standard ΛCDM model. Our estimation of the new diagnostic Omh {sup 2} from SDSS DR9 and DR11 data, namely, Omh {sup 2} ≈ 0.122 ± 0.01, which is equivalent to Ω{sub 0m} h {sup 2} for the spatially flat ΛCDM model, is in tension with the value Ω{sub 0m} h {sup 2} = 0.1426 ± 0.0025 determined for ΛCDM from Planck+WP. This tension is alleviated in models in which the cosmological constant was dynamically screened (compensated) in the past. Such evolving dark energy models display a pole in the effective equation of state of dark energy at high redshifts, which emerges as a smoking gun test for these theories.

  4. Acoustically evoked potentials in two cephalopods inferred using the auditory brainstem response (ABR) approach.

    PubMed

    Hu, Marian Y; Yan, Hong Young; Chung, Wen-Sung; Shiao, Jen-Chieh; Hwang, Pung-Pung

    2009-07-01

    It is still a matter of debate whether cephalopods can detect sound frequencies above 400 Hz. So far there is no proof for the detection of underwater sound above 400 Hz via a physiological approach. The controversy of whether cephalopods have a sound detection ability above 400 Hz was tested using the auditory brainstem response (ABR) approach, which has been successfully applied in fish, crustaceans, amphibians, reptiles and birds. Using ABR we found that auditory evoked potentials can be obtained in the frequency range 400 to 1500 Hz (Sepiotheutis lessoniana) and 400 to 1000 Hz (Octopus vulgaris), respectively. The thresholds of S. lessoniana were generally lower than those of O. vulgaris. PMID:19275944

  5. [Music-Acoustic Signals Controlled by Subject's Brain Potentials in the Correction of Unfavorable Functional States].

    PubMed

    Fedotchev, A I; Bondar, A T; Bakhchina, A V; Parin, S B; Polevaya, S A; Radchenko, G S

    2016-01-01

    Literature review and the results of own studies on the development and experimental testing of musical EEG neurofeedback technology are presented. The technology is based on exposure of subjects to music or music-like signals that are organized in strict accordance with the current values of brain potentials of the patient. The main attention is paid to the analysis of the effectiveness of several versions of the technology, using specific and meaningful for the individual narrow-frequency EEG oscillators during the correction of unfavorable changes of the functional state. PMID:27149824

  6. First cosmological constraints on dark energy from the radial baryon acoustic scale.

    PubMed

    Gaztañaga, Enrique; Miquel, Ramon; Sánchez, Eusebio

    2009-08-28

    We present cosmological constraints arising from the first measurement of the radial (line-of-sight) baryon acoustic oscillations (BAO) scale in the large scale structure traced by the galaxy distribution. Here we use these radial BAO measurements at z = 0.24 and z = 0.43 to derive new constraints on dark energy and its equation of state for a flat universe, without any other assumptions on the cosmological model: w = -1.14 + or - 0.39 (assumed constant), Omega(m) = 0.24(-0.05);(+0.06). If we drop the assumption of flatness and include previous cosmic microwave background and supernova data, we find w = -0.974 + or - 0.058, Omega(m) = 0.271 + or - 0.015, and Omega(k) = -0.002 + or - 0.006, in good agreement with a flat cold dark matter cosmology with a cosmological constant. To our knowledge, these are the most stringent constraints on these parameters to date under our stated assumptions. PMID:19792779

  7. Monitoring acoustic emission (AE) energy in slurry impingement using a new model for particle impact

    NASA Astrophysics Data System (ADS)

    Droubi, M. G.; Reuben, R. L.; White, G.

    2015-10-01

    A series of systematic impact tests have been carried out to investigate the influence of particle size, free stream velocity, particle impact angle, and nominal particle concentration on the amount of energy dissipated in a carbon steel target using a slurry impingement erosion test rig, as indicated by the acoustic emission (AE) recorded by a sensor mounted on the back of the target. Silica sand particles of mean particle size 152.5, 231, and 362.5 μm were used for impingement on the target at angles varying between 30° and 90° while the free stream velocity was changed between 4.2 and 12.7 m/s. In previous work by the authors, it was demonstrated that the AE time series associated with particle-laden air striking a carbon steel target could be described as the cumulation of individual particle arrival events each drawn from a statistical distribution model. The high arrival rate involved in a slurry jet poses challenges in resolving individual particle impact signatures in the AE record, and so the model has been extended in this paper to account for different particle carrier-fluids and to situations where arrivals cannot necessarily be resolved.

  8. Throughput and Energy Efficiency of a Cooperative Hybrid ARQ Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Ghosh, Arindam; Lee, Jae-Won; Cho, Ho-Shin

    2013-01-01

    Due to its efficiency, reliability and better channel and resource utilization, cooperative transmission technologies have been attractive options in underwater as well as terrestrial sensor networks. Their performance can be further improved if merged with forward error correction (FEC) techniques. In this paper, we propose and analyze a retransmission protocol named Cooperative-Hybrid Automatic Repeat reQuest (C-HARQ) for underwater acoustic sensor networks, which exploits both the reliability of cooperative ARQ (CARQ) and the efficiency of incremental redundancy-hybrid ARQ (IR-HARQ) using rate-compatible punctured convolution (RCPC) codes. Extensive Monte Carlo simulations are performed to investigate the performance of the protocol, in terms of both throughput and energy efficiency. The results clearly reveal the enhancement in performance achieved by the C-HARQ protocol, which outperforms both CARQ and conventional stop and wait ARQ (S&W ARQ). Further, using computer simulations, optimum values of various network parameters are estimated so as to extract the best performance out of the C-HARQ protocol. PMID:24217359

  9. Throughput and energy efficiency of a cooperative hybrid ARQ protocol for underwater acoustic sensor networks.

    PubMed

    Ghosh, Arindam; Lee, Jae-Won; Cho, Ho-Shin

    2013-01-01

    Due to its efficiency, reliability and better channel and resource utilization, cooperative transmission technologies have been attractive options in underwater as well as terrestrial sensor networks. Their performance can be further improved if merged with forward error correction (FEC) techniques. In this paper, we propose and analyze a retransmission protocol named Cooperative-Hybrid Automatic Repeat reQuest (C-HARQ) for underwater acoustic sensor networks, which exploits both the reliability of cooperative ARQ (CARQ) and the efficiency of incremental redundancy-hybrid ARQ (IR-HARQ) using rate-compatible punctured convolution (RCPC) codes. Extensive Monte Carlo simulations are performed to investigate the performance of the protocol, in terms of both throughput and energy efficiency. The results clearly reveal the enhancement in performance achieved by the C-HARQ protocol, which outperforms both CARQ and conventional stop and wait ARQ (S&W ARQ). Further, using computer simulations, optimum values of various network parameters are estimated so as to extract the best performance out of the C-HARQ protocol. PMID:24217359

  10. Health sensor for human body by using infrared, acoustic energy and magnetic signature

    NASA Astrophysics Data System (ADS)

    Wu, Jerry

    2013-05-01

    There is a general chain of events that applies to infections. Human body infection could causes by many different types of bacteria and virus in different areas or organ systems. In general, doctor can't find out the right solution/treatment for infections unless some certain types of bacteria or virus are detected. These detecting processes, usually, take few days to one week to accomplish. However, some infections of the body may not be able to detect at first round and the patient may lose the timing to receive the proper treatment. In this works, we base on Chi's theory which is an invisible circulation system existed inside the body and propose a novel health sensor which summarizes human's infrared, acoustic energy and magnetic signature and find out, in minutes, the most possible area or organ system that cause the infection just like what Chi-Kung master can accomplish. Therefore, the detection process by doctor will be shortened and it raises the possibility to give the proper treatment to the patient in the earliest timing.

  11. Kinetic modeling of ultrasound-assisted extraction of phenolic compounds from grape marc: influence of acoustic energy density and temperature.

    PubMed

    Tao, Yang; Zhang, Zhihang; Sun, Da-Wen

    2014-07-01

    The effects of acoustic energy density (6.8-47.4 W/L) and temperature (20-50 °C) on the extraction yields of total phenolics and tartaric esters during ultrasound-assisted extraction from grape marc were investigated in this study. The ultrasound treatment was performed in a 25-kHz ultrasound bath system and the 50% aqueous ethanol was used as the solvent. The initial extraction rate and final extraction yield increased with the increase of acoustic energy density and temperature. The two site kinetic model was used to simulate the kinetics of extraction process and the diffusion model based on the Fick's second law was employed to determine the effective diffusion coefficient of phenolics in grape marc. Both models gave satisfactory quality of data fit. The diffusion process was divided into one fast stage and one slow stage and the diffusion coefficients in both stages were calculated. Within the current experimental range, the diffusion coefficients of total phenolics and tartaric esters for both diffusion stages increased with acoustic energy density. Meanwhile, the rise of temperature also resulted in the increase of diffusion coefficients of phenolics except the diffusion coefficient of total phenolics in the fast stage, the value of which being the highest at 40 °C. Moreover, an empirical equation was suggested to correlate the effective diffusion coefficient of phenolics in grape marc with acoustic energy density and temperature. In addition, the performance comparison of ultrasound-assisted extraction and convention methods demonstrates that ultrasound is an effective and promising technology to extract bioactive substances from grape marc. PMID:24613646

  12. The Potential Overlapping Roles of the Ear and Lateral Line in Driving "Acoustic" Responses.

    PubMed

    Higgs, Dennis M; Radford, Craig A

    2016-01-01

    Examination of fish responses to sound stimuli has a rich and varied history but it is not always clear when responses are true measures of hearing or the lateral-line. The central innervation of auditory and lateral-line sensory afferents lie in close proximity in the brainstem and both sets of receptors are, at heart, hair cell-based particle motion detectors. While it is possible to separately measure physiological activity of these two receptor subtypes, many studies of fish "hearing" use whole brain potentials or behavioural assays in complex sound fields where it is not possible to distinguish inputs. We argue here that, as often measured, what is thought of as fish "hearing" is often a multisensory response of both auditory and lateral line receptors. We also argue that in many situations where fish use sound stimuli, the behaviour is also an integrative response of both systems, due to the often close proximity of fish during sound communication. We end with a set of recommendations for better understanding the separate and combined roles of ear and lateral-line hair cells as well as an acknowledgment of the seminal and continuing contributions of Arthur N. Popper and Richard R. Fay to this field. PMID:26515318

  13. Potential contribution of the wastewater sector to energy supply.

    PubMed

    Heubeck, S; de Vos, R M; Craggs, R

    2011-01-01

    The biological treatment of wastewater could yield high energy fuels such as methane and alcohols, however most conventional treatment systems do not recover this energy potential. with a simple model of the energy yields of various wastewater treatment technologies it is possible to demonstrate how minor shifts in technology selection can lead the industry from being identified as predominantly energy intensive, to being recognised as a source of energy resources. The future potential energy yield is estimated by applying energy yield factors to alternative use scenarios of the same wastewater loads. The method for identifying the energy potential of wastewater was demonstrated for the New Zealand wastewater sector, but can equally be applied to other countries or regions. The model suggests that by using technologies that maximise the recovery of energy from wastewater, the potential energy yield from this sector would be substantially increased (six fold for New Zealand). PMID:21866779

  14. A New Approach to Energy Integral for Investigation of Dust—Ion Acoustic (DIA) Waves in Multi-Component Plasmas with Quantum Effects in Inertia Less Electrons

    NASA Astrophysics Data System (ADS)

    Kalita, B. C.; Kalita, R.

    2015-06-01

    Dust-ion acoustic waves are investigated in this model of plasma consisting of negatively charged dusts, cold ions and inertia less quantum effected electrons with the help of a typical energy integral. In this case, a new technique is applied formulating a differential equation to establish the energy integral in case of multi-component plasmas which is not possible in general. Dust-ion acoustic (DIA) compressive and rarefactive, supersonic and subsonic solitons of various amplitudes are established. The consideration of smaller order nonlinearity in support of the newly established quantum plasma model is observed to generate small amplitude solitons at the decrease of Mach number. The growths of soliton amplitudes and potential depths are found more sensitive to the density of quantum electrons. The small density ratio r(= 1 - f) with a little quantized electrons supplemented by the dust charges Zd and the in-deterministic new quantum parameter C2 are found responsible to finally support the generation of small amplitude solitons admissible for the model.

  15. Method and system for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Johnson Paul A.; Ten Cate, James A.; Guyer, Robert; Le Bas, Pierre-Yves; Vu, Cung; Nihei, Kurt; Schmitt, Denis P.; Skelt, Christopher

    2012-02-14

    A compact array of transducers is employed as a downhole instrument for acoustic investigation of the surrounding rock formation. The array is operable to generate simultaneously a first acoustic beam signal at a first frequency and a second acoustic beam signal at a second frequency different than the first frequency. These two signals can be oriented through an azimuthal rotation of the array and an inclination rotation using control of the relative phases of the signals from the transmitter elements or electromechanical linkage. Due to the non-linearity of the formation, the first and the second acoustic beam signal mix into the rock formation where they combine into a collimated third signal that propagates in the formation along the same direction than the first and second signals and has a frequency equal to the difference of the first and the second acoustic signals. The third signal is received either within the same borehole, after reflection, or another borehole, after transmission, and analyzed to determine information about rock formation. Recording of the third signal generated along several azimuthal and inclination directions also provides 3D images of the formation, information about 3D distribution of rock formation and fluid properties and an indication of the dynamic acoustic non-linearity of the formation.

  16. Can seismic (destructive) energy be stored after conversion into useful electrical or acoustic energy?

    NASA Astrophysics Data System (ADS)

    Verma, Umesh P.; Sinha, Madhurendra N.

    2014-06-01

    Since the dawn of precursory revolution in the seismology and electromagnetic radiation platform., F.T. Freund (2010) et.al, have used piezoelectric effect on the crustal geo-materials and emanation of seismic pre signals frequently. Their effect in form of ULF and VHF are commonly detected (by Greece and American seismologists)in the upper ionosphere from surface of globe. TEC, OLR. MMC are the consequent instrumentation in acquiring data to these pre-earthquake signals. Our attempt is to detect the signals prior to earthquake due to impending stress in the area and store the spreading destructive energy to electrical voltage applying the mathematics of piezoelectric equations and algebra. Energy released during seismic eruption is in the range of 10 13 to 1018 Joule for each event of 6 to 8 Mw. Spread and propagation of energy follows the Maxwell theory of wave equation and fundamental law of electricity and electromagnetism. Stress accumulated within the crustal block is triggered into bringing about geophysical and geochemical changes within the reservoir rocks interacting stress. Study made by pioneers in the seismic precursory development states generation of charge and coronal discharge prior seismicity within the rocks under stress. This is consequence to admixing of positive charge developed at unstressed volume and negative at stressed sub volume of rocks1 [F.T.Freidemann2010]. Ionosphere proturbance in form of ULF, ELF, ELS and EQL, EQS are the projected consequence of electromagnetic wave propagation 2 [10,11,15 ] Harnessing of electrical components from the energy propagated due to stress inducing EM waves is the aim of paper. Electrical discharge prior to seismicity within geo-materials is established phenomena which can be calibrated with the piezoelectric sensors application implanted for detection and harnessing the signals. These prior signals induced in form of electromagnetic response are felicitated into being converted into electrical energy

  17. Airbursts as a viable source of seismic and acoustic energy for the 2016 InSight geophysical lander mission to Mars: analysis using terrestrial analogues

    NASA Astrophysics Data System (ADS)

    Taylor, Jennifer; Wookey, James; Teanby, Nick

    2014-05-01

    The explosion of a bolide as a terminal airburst, before impact into a planetary surface, is a well-documented source of both seismic and acoustic energy[1]. Here we aim to define some diagnostic properties of a recorded airburst time-series and determine detectability criteria for such events for a single station seismo-acoustic station on the Martian surface. In 2016 NASA will launch the InSight geophysical monitoring system. This lander will carry in its SEIS payload two 3-component seismic instruments - the Short Period (SP) and Very Broadband (VBB) seismometers, as well as a micro-barometer for measurement of atmospheric pressure fluctuations. The SEIS and MB packages aboard InSight could potentially be used together for seismo-acoustic detection of impact or airburst events. In past studies, this technique has been used to analyse and model the Washington State Bolide[2] and, more recently, the Chelyabinsk fireball in 2013[3]. Using a multi-station array, it is possible to estimate total kinetic energy of a bolide, its line-of-sight direction and the approximate time of its terminal burst[4]. However, with only a single station, as would be the case on Mars, more creative methods must be employed to extract information from the event. We explore the diagnostic waveform properties of an airburst, including various arrivals from the event. We also show how dominant frequency changes with distance from the event, altitude and yield. Several terrestrial events are analysed, including the 2013 Chelyabinsk fireball. We present theoretical calculations of the likely proportion of bolide terminal bursts on Mars relative to impacts, based on differences in the structure and composition of the Martian atmosphere. We go on to predict the seismic arrivals that may be observed by InSight from the coupling of the acoustic blast into the Martian crust. It is hoped that these diagnostic tools will be useful to identify and quantify bolide terminal bursts on Mars over the

  18. An experimental study of vibration based energy harvesting in dynamically tailored structures with embedded acoustic black holes

    NASA Astrophysics Data System (ADS)

    Zhao, Liuxian; Conlon, Stephen C.; Semperlotti, Fabio

    2015-06-01

    In this paper, we present an experimental investigation on the energy harvesting performance of dynamically tailored structures based on the concept of embedded acoustic black holes (ABHs). Embedded ABHs allow tailoring the wave propagation characteristics of the host structure creating structural areas with extreme levels of energy density. Experiments are conducted on a tapered plate-like aluminum structure with multiple embedded ABH features. The dynamic response of the structure is tested via laser vibrometry in order to confirm the vibration localization and the passive wavelength sweep characteristic of ABH embedded tapers. Vibrational energy is extracted from the host structure and converted into electrical energy by using ceramic piezoelectric discs bonded on the ABHs and shunted on an external electric circuit. The energy harvesting performance is investigated both under steady state and transient excitation. The experimental results confirm that the dynamic tailoring produces a drastic increase in the harvested energy independently from the nature of the excitation input.

  19. Simultaneous backward data transmission and power harvesting in an ultrasonic transcutaneous energy transfer link employing acoustically dependent electric impedance modulation.

    PubMed

    Ozeri, Shaul; Shmilovitz, Doron

    2014-09-01

    The advancement and miniaturization of body implanted medical devices pose several challenges to Ultrasonic Transcutaneous Energy Transfer (UTET), such as the need to reduce the size of the piezoelectric resonator, and the need to maximize the UTET link power-transfer efficiency. Accordingly, the same piezoelectric resonator that is used for energy harvesting at the body implant, may also be used for ultrasonic backward data transfer, for instance, through impedance modulation. This paper presents physical considerations and design guidelines of the body implanted transducer of a UTET link with impedance modulation for a backward data transfer. The acoustic matching design procedure was based on the 2×2 transfer matrix chain analysis, in addition to the Krimholtz Leedom and Matthaei KLM transmission line model. The UTET power transfer was carried out at a frequency of 765 kHz, continuous wave (CW) mode. The backward data transfer was attained by inserting a 9% load resistance variation around its matched value (550 Ohm), resulting in a 12% increase in the acoustic reflection coefficient. A backward data transmission rate of 1200 bits/s was experimentally demonstrated using amplitude shift keying, simultaneously with an acoustic power transfer of 20 mW to the implant. PMID:24861424

  20. HIGH ENERGY PHYSICS POTENTIAL AT MUON COLLIDERS

    SciTech Connect

    PARSA,Z.

    2000-04-07

    In this paper, high energy physics possibilities and future colliders are discussed. The {mu}{sup +} {mu}{sup {minus}} collider and experiments with high intensity muon beams as the stepping phase towards building Higher Energy Muon Colliders (HEMC) are briefly reviewed and encouraged.

  1. Energy in America: Progress and Potential.

    ERIC Educational Resources Information Center

    American Petroleum Inst., Washington, DC.

    An overview of America's energy situation is presented with emphasis on recent progress, the risk of depending upon foreign oil, and policy choices. Section one reviews the energy problems of the 1970s, issues of the 1980s, concerns for the future, and choices that if made today could alleviate future problems. Section two examines past problems,…

  2. The Potential Energy of an Autoencoder.

    PubMed

    Kamyshanska, Hanna; Memisevic, Roland

    2015-06-01

    Autoencoders are popular feature learning models, that are conceptually simple, easy to train and allow for efficient inference. Recent work has shown how certain autoencoders can be associated with an energy landscape, akin to negative log-probability in a probabilistic model, which measures how well the autoencoder can represent regions in the input space. The energy landscape has been commonly inferred heuristically, by using a training criterion that relates the autoencoder to a probabilistic model such as a Restricted Boltzmann Machine (RBM). In this paper we show how most common autoencoders are naturally associated with an energy function, independent of the training procedure, and that the energy landscape can be inferred analytically by integrating the reconstruction function of the autoencoder. For autoencoders with sigmoid hidden units, the energy function is identical to the free energy of an RBM, which helps shed light onto the relationship between these two types of model. We also show that the autoencoder energy function allows us to explain common regularization procedures, such as contractive training, from the perspective of dynamical systems. As a practical application of the energy function, a generative classifier based on class-specific autoencoders is presented. PMID:26357347

  3. Energy conservation potential of surface modification technologies

    SciTech Connect

    Le, H.K.; Horne, D.M.; Silberglitt, R.S.

    1985-09-01

    This report assesses the energy conservation impact of surface modification technologies on the metalworking industries. The energy conservation impact of surface modification technologies on the metalworking industries is assessed by estimating their friction and wear tribological sinks and the subsequent reduction in these sinks when surface modified tools are used. Ion implantation, coatings, and laser and electron beam surface modifications are considered.

  4. Prediction of interior noise due to random acoustic or turbulent boundary layer excitation using statistical energy analysis

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.

    1990-01-01

    The feasibility of predicting interior noise due to random acoustic or turbulent boundary layer excitation was investigated in experiments in which a statistical energy analysis model (VAPEPS) was used to analyze measurements of the acceleration response and sound transmission of flat aluminum, lucite, and graphite/epoxy plates exposed to random acoustic or turbulent boundary layer excitation. The noise reduction of the plate, when backed by a shallow cavity and excited by a turbulent boundary layer, was predicted using a simplified theory based on the assumption of adiabatic compression of the fluid in the cavity. The predicted plate acceleration response was used as input in the noise reduction prediction. Reasonable agreement was found between the predictions and the measured noise reduction in the frequency range 315-1000 Hz.

  5. High-Q cross-plate phononic crystal resonator for enhanced acoustic wave localization and energy harvesting

    NASA Astrophysics Data System (ADS)

    Yang, Aichao; Li, Ping; Wen, Yumei; Yang, Chao; Wang, Decai; Zhang, Feng; Zhang, Jiajia

    2015-05-01

    A high-Q cross-plate phononic crystal resonator (Cr-PCR) coupled with an electromechanical Helmholtz resonator (EMHR) is proposed to improve acoustic wave localization and energy harvesting. Owing to the strongly directional wave-scattering effect of the cross-plate corners, strong confinement of acoustic waves emerges. Consequently, the proposed Cr-PCR structure exhibits ∼353.5 times higher Q value and ∼6.1 times greater maximum pressure amplification than the phononic crystal resonator (Cy-PCR) (consisting of cylindrical scatterers) of the same size. Furthermore, the harvester using the proposed Cr-PCR and the EMHR has ∼22 times greater maximum output-power volume density than the previous harvester using Cy-PCR and EMHR structures.

  6. Challenge of Using Passive Acoustic Monitoring in High-Energy Environments: UK Tidal Environments and Other Case Studies.

    PubMed

    Booth, Cormac G

    2016-01-01

    The use of passive acoustic monitoring (PAM) around marine developments is commonplace. A buffer-based PAM system (e.g., C-POD) is a cost-effective method for assessing cetacean acoustic presence. Devices have been deployed by Sea Mammal Research Unit (SMRU) Marine around the United Kingdom, allowing an examination of the performance of C-PODs with respect to background noise, tilt angle, and environmental factors. C-PODs were found to often only monitor for a few seconds of each minute, resulting in significant loss of monitoring time. Issues were likely driven by environmental and deployment factors. The practical limitations of buffer-based PAM systems in high-energy/noisy environments are indicated here. PMID:26610949

  7. Stretching the inflaton potential with kinetic energy

    SciTech Connect

    Lidsey, James E.

    2007-08-15

    Inflation near a maximum of the potential is studied when nonlocal derivative operators are included in the inflaton Lagrangian. Such terms can impose additional sources of friction on the field. For an arbitrary spacetime geometry, these effects can be quantified in terms of a local field theory with a potential whose curvature around the turning point is strongly suppressed. This implies that a prolonged phase of slow-roll inflation can be achieved with potentials that are otherwise too steep to drive quasiexponential expansion. We illustrate this mechanism within the context of p-adic string theory.

  8. 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.

  9. Energy functions for rubber from microscopic potentials

    NASA Astrophysics Data System (ADS)

    Johal, A. S.; Dunstan, D. J.

    2007-04-01

    The finite deformation theory of rubber and related materials is based on energy functions that describe the macroscopic response of these materials under deformation. Energy functions and elastic constants are here derived from a simple microscopic (ball-and-spring) model. Exact uniaxial force-extension relationships are given for Hooke's Law and for the thermodynamic entropy-based microscopic model using the Gaussian and the inverse Langevin statistical approximations. Methods are given for finding the energy functions as expansions of tensor invariants of deformation, with exact solutions for functions that can be expressed as expansions in even powers of the extension. Comparison with experiment shows good agreement with the neo-Hookean energy function and we show how this derives directly from the simple Gaussian statistical model with a small modification.

  10. Stronger efferent suppression of cochlear neural potentials by contralateral acoustic stimulation in awake than in anesthetized chinchilla

    PubMed Central

    Aedo, Cristian; Tapia, Eduardo; Pavez, Elizabeth; Elgueda, Diego; Delano, Paul H.; Robles, Luis

    2015-01-01

    There are two types of sensory cells in the mammalian cochlea, inner hair cells, which make synaptic contact with auditory-nerve afferent fibers, and outer hair cells that are innervated by crossed and uncrossed medial olivocochlear (MOC) efferent fibers. Contralateral acoustic stimulation activates the uncrossed efferent MOC fibers reducing cochlear neural responses, thus modifying the input to the central auditory system. The chinchilla, among all studied mammals, displays the lowest percentage of uncrossed MOC fibers raising questions about the strength and frequency distribution of the contralateral-sound effect in this species. On the other hand, MOC effects on cochlear sensitivity have been mainly studied in anesthetized animals and since the MOC-neuron activity depends on the level of anesthesia, it is important to assess the influence of anesthesia in the strength of efferent effects. Seven adult chinchillas (Chinchilla laniger) were chronically implanted with round-window electrodes in both cochleae. We compared the effect of contralateral sound in awake and anesthetized condition. Compound action potentials (CAP) and cochlear microphonics (CM) were measured in the ipsilateral cochlea in response to tones in absence and presence of contralateral sound. Control measurements performed after middle-ear muscles section in one animal discarded any possible middle-ear reflex activation. Contralateral sound produced CAP amplitude reductions in all chinchillas, with suppression effects greater by about 1–3 dB in awake than in anesthetized animals. In contrast, CM amplitude increases of up to 1.9 dB were found in only three awake chinchillas. In both conditions the strongest efferent effects were produced by contralateral tones at frequencies equal or close to those of ipsilateral tones. Contralateral CAP suppressions for 1–6 kHz ipsilateral tones corresponded to a span of uncrossed MOC fiber innervation reaching at least the central third of the chinchilla

  11. Current-driven ion-acoustic and potential-relaxation instabilities excited in plasma plume during electron beam welding

    SciTech Connect

    Trushnikov, D. N.; Mladenov, G. M. Koleva, E. G.; Belenkiy, V. Ya. Varushkin, S. V.

    2014-04-15

    Many papers have sought correlations between the parameters of secondary particles generated above the beam/work piece interaction zone, dynamics of processes in the keyhole, and technological processes. Low- and high-frequency oscillations of the current, collected by plasma have been observed above the welding zone during electron beam welding. Low-frequency oscillations of secondary signals are related to capillary instabilities of the keyhole, however; the physical mechanisms responsible for the high-frequency oscillations (>10 kHz) of the collected current are not fully understood. This paper shows that peak frequencies in the spectra of the collected high-frequency signal are dependent on the reciprocal distance between the welding zone and collector electrode. From the relationship between current harmonics frequency and distance of the collector/welding zone, it can be estimated that the draft velocity of electrons or phase velocity of excited waves is about 1600 m/s. The dispersion relation with the properties of ion-acoustic waves is related to electron temperature 10 000 K, ion temperature 2 400 K and plasma density 10{sup 16} m{sup −3}, which is analogues to the parameters of potential-relaxation instabilities, observed in similar conditions. The estimated critical density of the transported current for creating the anomalous resistance state of plasma is of the order of 3 A·m{sup −2}, i.e. 8 mA for a 3–10 cm{sup 2} collector electrode. Thus, it is assumed that the observed high-frequency oscillations of the current collected by the positive collector electrode are caused by relaxation processes in the plasma plume above the welding zone, and not a direct demonstration of oscillations in the keyhole.

  12. Stronger efferent suppression of cochlear neural potentials by contralateral acoustic stimulation in awake than in anesthetized chinchilla.

    PubMed

    Aedo, Cristian; Tapia, Eduardo; Pavez, Elizabeth; Elgueda, Diego; Delano, Paul H; Robles, Luis

    2015-01-01

    There are two types of sensory cells in the mammalian cochlea, inner hair cells, which make synaptic contact with auditory-nerve afferent fibers, and outer hair cells that are innervated by crossed and uncrossed medial olivocochlear (MOC) efferent fibers. Contralateral acoustic stimulation activates the uncrossed efferent MOC fibers reducing cochlear neural responses, thus modifying the input to the central auditory system. The chinchilla, among all studied mammals, displays the lowest percentage of uncrossed MOC fibers raising questions about the strength and frequency distribution of the contralateral-sound effect in this species. On the other hand, MOC effects on cochlear sensitivity have been mainly studied in anesthetized animals and since the MOC-neuron activity depends on the level of anesthesia, it is important to assess the influence of anesthesia in the strength of efferent effects. Seven adult chinchillas (Chinchilla laniger) were chronically implanted with round-window electrodes in both cochleae. We compared the effect of contralateral sound in awake and anesthetized condition. Compound action potentials (CAP) and cochlear microphonics (CM) were measured in the ipsilateral cochlea in response to tones in absence and presence of contralateral sound. Control measurements performed after middle-ear muscles section in one animal discarded any possible middle-ear reflex activation. Contralateral sound produced CAP amplitude reductions in all chinchillas, with suppression effects greater by about 1-3 dB in awake than in anesthetized animals. In contrast, CM amplitude increases of up to 1.9 dB were found in only three awake chinchillas. In both conditions the strongest efferent effects were produced by contralateral tones at frequencies equal or close to those of ipsilateral tones. Contralateral CAP suppressions for 1-6 kHz ipsilateral tones corresponded to a span of uncrossed MOC fiber innervation reaching at least the central third of the chinchilla cochlea

  13. Energy Savings Potential and Research & Development Opportunities for Commercial Refrigeration

    SciTech Connect

    none,

    2009-09-01

    This study documents the energy consumption of commercial refrigeration equipment (CRE) in the U.S. and evaluated the energy savings potential of various technologies and energy efficiency measures that could be applied to such equipment. The study provided an overview of CRE applications, assessed the energy-savings potential of CRE in the U.S., outline key barriers to adoption of energy-savings technologies, and recommended opportunities for advanced energy saving technology research. The study was modeled after an earlier 1996 report by Arthur D. Little, Inc., and updated key information, examined more equipment types, and outlined long-term research and development opportunities.

  14. Bubbles trapped at the coupling surface of the treatment head significantly reduce acoustic energy delivered in shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Pishchalnikov, Yuri A.; McAteer, James A.; Pishchalnikova, Irina V.; Beard, Spencer; Williams, James C.; Bailey, Michael R.

    2006-05-01

    The coupling efficiency of a "dry head" electromagnetic lithotripter (Dornier Compact Delta) was studied in vitro. A fiber-optic probe hydrophone (FOPH-500) was positioned in a test tank filled with degassed water. The tank was coupled through a semi-transparent latex membrane to the water-filled cushion of the lithotripter head, so that bubbles (air pockets) trapped between the two coupling surfaces could be easily observed and photographed. When gel was applied to both the latex membrane and the water cushion, numerous bubbles (some several millimeters in diameter) could be seen at the coupling interface. Hydrophone measurements in the geometric focus of the lithotripter showed that the acoustic pressure could be two times lower when bubbles were present than when they were manually removed. In our in vitro design, trapped bubbles could be easily observed and therefore removed from the acoustic path. However, during patient treatment with a dry-head lithotripter one cannot see whether bubbles are trapped against the skin. This study provides a demonstration of the dramatic effect that trapped bubbles can have on the amount of acoustic energy actually delivered for treatment.

  15. Potential Energy Sources Pose Mining Problem

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1974

    1974-01-01

    Summarizes the discussions of a Division of Industrial and Engineering Chemistry symposium on solids handling for synthetic fuels production. Included is a description of technical difficulties with the use of coal seams and deposits of oil shale and oil sand as potential sources of fuel. (CC)

  16. Energy savings potential from energy-conserving irrigation systems

    SciTech Connect

    Wilfert, G.L.; Patton, W.P.; Harrer, B.J.; Clark, M.A.

    1982-11-01

    This report systematically compares, within a consistent framework, the technical and economic characteristics of energy-conserving irrigation systems with those of conventional irrigation systems and to determine total energy savings. Levelized annual costs of owning and operating both energy-conserving and conventional irrigation systems have been developed and compared for all 17 states to account for the differences in energy costs and irrigation conditions in each state. Market penetration of energy-conserving systems is assessed for those systems having lower levelized annual costs than conventional systems performing the same function. Annual energy savings were computed by matching the energy savings per system with an assumed maximum market penetration of 100 percent in those markets where the levelized annual costs of energy-conserving systems are lower than the levelized annual costs of conventional systems.

  17. Potential production of energy cane for fuel in the Caribbean

    SciTech Connect

    Samuels, G.

    1984-12-01

    Sugarcane presents a tremendous potential as a renewable energy source for the non-oil producing countries of the Caribbean. The energy cane concept is sugarcane managed for maximum dry matter (total fermentable solids for alcohol fuel and combustible solids for electricity) rather than sucrose. The use of sugarcane as a renewable energy source can provide a solution, either partial or total, to the Caribbean energy problem. Sugar cane production and the use of this crop as a renewable energy source are described.

  18. Preliminary evaluation of wind energy potential: Cook Inlet area, Alaska

    SciTech Connect

    Hiester, T.R.

    1980-06-01

    This report summarizes work on a project performed under contract to the Alaska Power Administration (APA). The objective of this research was to make a preliminary assessment of the wind energy potential for interconnection with the Cook Inlet area electric power transmission and distribution systems, to identify the most likely candidate regions (25 to 100 square miles each) for energy potential, and to recommend a monitoring program sufficient to quantify the potential.

  19. Ion-acoustic cnoidal waves in a quantum plasma

    SciTech Connect

    Mahmood, S.; Haas, F.

    2014-10-15

    Nonlinear ion-acoustic cnoidal wave structures are studied in an unmagnetized quantum plasma. Using the reductive perturbation method, a Korteweg-de Vries equation is derived for appropriate boundary conditions and nonlinear periodic wave solutions are obtained. The corresponding analytical solution and numerical plots of the ion-acoustic cnoidal waves and solitons in the phase plane are presented using the Sagdeev pseudo-potential approach. The variations in the nonlinear potential of the ion-acoustic cnoidal waves are studied at different values of quantum parameter H{sub e} which is the ratio of electron plasmon energy to electron Fermi energy defined for degenerate electrons. It is found that both compressive and rarefactive ion-acoustic cnoidal wave structures are formed depending on the value of the quantum parameter. The dependence of the wavelength and frequency on nonlinear wave amplitude is also presented.

  20. Turbine under Gulf Stream: Potential energy source

    SciTech Connect

    Venezia, W.A.; Holt, J.

    1995-09-01

    Turbine under the Gulf Stream (TUGS) is a project to design, build, and deploy the prototypes necessary to demonstrate the economic and technical feasibility of generating electric power from the Gulf Stream. The project is based in part on new generator designs and emerging materials technologies. Its successful completion would demonstrate the technology and produce prototype turbines that can be mass produced and sold with service support. Past research and experimentation indicates that energy can be generated from the Gulf Stream. Problems exist such as fluctuations in the current`s axis and inconsistency. Above all, the ocean is a difficult environment in which to work. Therefore, the question is not whether or not a generator can be put in the ocean to generate electricity, but rather can it be done in an economically and environmentally sound way and still be practical?

  1. 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.

  2. Topological charge pump by surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Yi, Zheng; Shi-Ping, Feng; Shi-Jie, Yang

    2016-06-01

    Quantized electron pumping by the surface acoustic wave across barriers created by a sequence of split metal gates is interpreted from the viewpoint of topology. The surface acoustic wave serves as a one-dimensional periodical potential whose energy spectrum possesses the Bloch band structure. The time-dependent phase plays the role of an adiabatic parameter of the Hamiltonian which induces a geometrical phase. The pumping currents are related to the Chern numbers of the filled bands below the Fermi energy. Based on this understanding, we predict a novel effect of quantized but non-monotonous current plateaus simultaneously pumped by two homodromous surface acoustic waves. Project supported by the National Natural Science Foundation of China (Grant No. 11374036) and the National Basic Research Program of China (Grant No. 2012CB821403).

  3. Alfvén acoustic channel for ion energy in high-beta tokamak plasmas.

    PubMed

    Bierwage, Andreas; Aiba, Nobuyuki; Shinohara, Kouji

    2015-01-01

    When the plasma beta (ratio of thermal to magnetic pressure) in the core of a tokamak is raised to values of several percent, as required for a thermonuclear fusion reactor, continuous spectra of long-wavelength slow magnetosonic waves enter the frequency band occupied by continuous spectra of shear Alfvén waves. It is found that these two branches can couple strongly, so that Alfvén modes that are resonantly driven by suprathermal ions transfer some of their energy to sound waves. Since sound waves are heavily damped by thermal ion Landau resonances, these results reveal a new energy channel that contributes to the damping of Alfvénic instabilities and the noncollisional heating of bulk ions, with potentially important consequences for confinement and fusion performance. PMID:25615474

  4. Alfvén Acoustic Channel for Ion Energy in High-Beta Tokamak Plasmas

    NASA Astrophysics Data System (ADS)

    Bierwage, Andreas; Aiba, Nobuyuki; Shinohara, Kouji

    2015-01-01

    When the plasma beta (ratio of thermal to magnetic pressure) in the core of a tokamak is raised to values of several percent, as required for a thermonuclear fusion reactor, continuous spectra of long-wavelength slow magnetosonic waves enter the frequency band occupied by continuous spectra of shear Alfvén waves. It is found that these two branches can couple strongly, so that Alfvén modes that are resonantly driven by suprathermal ions transfer some of their energy to sound waves. Since sound waves are heavily damped by thermal ion Landau resonances, these results reveal a new energy channel that contributes to the damping of Alfvénic instabilities and the noncollisional heating of bulk ions, with potentially important consequences for confinement and fusion performance.

  5. Periodic discrete energy for long-range potentials

    NASA Astrophysics Data System (ADS)

    Hardin, D. P.; Saff, E. B.; Simanek, B.

    2014-12-01

    We consider periodic energy problems in Euclidean space with a special emphasis on long-range potentials that cannot be defined through the usual infinite sum. One of our main results builds on more recent developments of Ewald summation to define the periodic energy corresponding to a large class of long-range potentials. Two particularly interesting examples are the logarithmic potential and the Riesz potential when the Riesz parameter is smaller than the dimension of the space. For these examples, we use analytic continuation methods to provide concise formulas for the periodic kernel in terms of the Epstein Hurwitz Zeta function. We apply our energy definition to deduce several properties of the minimal energy including the asymptotic order of growth and the distribution of points in energy minimizing configurations as the number of points becomes large. We conclude with some detailed calculations in the case of one dimension, which shows the utility of this approach.

  6. Bandwidth Study on Energy Use and Potential Energy Savings Opportunities in U.S. Petroleum Refining

    SciTech Connect

    Sabine Brueske, Caroline Kramer, Aaron Fisher

    2015-06-01

    Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. petroleum refining. The study relies on multiple sources to estimate the energy used in nine individual process areas, representing 68% of sector-wide energy consumption. Energy savings opportunities for individual processes are based on technologies currently in use or under development; these potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

  7. Bandwidth Study on Energy Use and Potential Energy Saving Opportunities in U.S. Chemical Manufacturing

    SciTech Connect

    Sabine Brueske, Caroline Kramer, Aaron Fisher

    2015-06-01

    Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. chemical manufacturing. The study relies on multiple sources to estimate the energy used in the production of 74 individual chemicals, representing 57% of sector-wide energy consumption. Energy savings opportunities for individual chemicals and for 15 subsectors of chemicals manufacturing are based on technologies currently in use or under development; these potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

  8. Scattering with absorptive interaction: Energy-dependent potentials

    NASA Astrophysics Data System (ADS)

    Cassing, W.; Stingl, M.; Weiguny, A.

    1983-05-01

    The energy dependence and analytic structure of the effective interaction for elastic scattering of composite particles are investigated using Feshbach's projection technique. A generalized Levinson theorem is established for complex, nonlocal, and energy-dependent interactions. The analytical results are illustrated by means of Argand diagrams for a solvable model and the effect of energy averaging is discussed. NUCLEAR REACTIONS Scattering theory, S matrix for absorptive, energy-dependent potentials, Levinson theorem.

  9. Energy Consumption and Renewable Energy Development Potential on Indian Lands

    EIA Publications

    2000-01-01

    Includes information on the electricity use and needs of Indian households and tribes, the comparative electricity rates that Indian households are paying, and the potential for renewable resources development of Indian lands.

  10. Asymptotic modal analysis and statistical energy analysis of an acoustic cavity

    NASA Technical Reports Server (NTRS)

    Kubota, Y.; Dionne, H. D.; Dowell, E. H.

    1988-01-01

    A basic asymptotic theory for structural wall/acoustic cavity interaction is presented, and the analysis is illustrated with examples of the acoustic cavity response to a prescribed wall motion. Although, when spatially averaged, the classical modal analysis (CMA) response approaches the asymptotic modal analysis (AMA) response more rapidly as the number of modes increases, it is shown that information about local response intensification is lost in the averaging process. A larger bandwidth at a given center frequency is found to contain more excited modes than a smaller bandwidth; however, the AMA is slightly more accurate in the smaller bandwidth. All AMA asymptotes were shown to be approached from below by a CMA with fixed bandwidth and increasing center frequency.

  11. System for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian; Nihei, Kurt T.; Schmitt, Denis P.; Skelt, Christopher

    2012-07-31

    In some aspects of the invention, a device, positioned within a well bore, configured to generate and direct an acoustic beam into a rock formation around a borehole is disclosed. The device comprises a source configured to generate a first signal at a first frequency and a second signal at a second frequency; a transducer configured to receive the generated first and the second signals and produce acoustic waves at the first frequency and the second frequency; and a non-linear material, coupled to the transducer, configured to generate a collimated beam with a frequency equal to the difference between the first frequency and the second frequency by a non-linear mixing process, wherein the non-linear material includes one or more of a mixture of liquids, a solid, a granular material, embedded microspheres, or an emulsion.

  12. System for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian; Nihei, Kurt T.; Schmitt, Denis P.; Skelt, Christopher

    2012-09-04

    In some aspects of the invention, a device, positioned within a well bore, configured to generate and direct an acoustic beam into a rock formation around a borehole is disclosed. The device comprises a source configured to generate a first signal at a first frequency and a second signal at a second frequency; a transducer configured to receive the generated first and the second signals and produce acoustic waves at the first frequency and the second frequency; and a non-linear material, coupled to the transducer, configured to generate a collimated beam with a frequency equal to the difference between the first frequency and the second frequency by a non-linear mixing process, wherein the non-linear material includes one or more of a mixture of liquids, a solid, a granular material, embedded microspheres, or an emulsion.

  13. Device and method for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian; Nihei, Kurt; Schmitt, Denis P.; Skelt, Christopher

    2010-11-23

    In some aspects of the invention, a device, positioned within a well bore, configured to generate and direct an acoustic beam into a rock formation around a borehole is disclosed. The device comprises a source configured to generate a first signal at a first frequency and a second signal at a second frequency; a transducer configured to receive the generated first and the second signals and produce acoustic waves at the first frequency and the second frequency; and a non-linear material, coupled to the transducer, configured to generate a collimated beam with a frequency equal to the difference between the first frequency and the second frequency by a non-linear mixing process, wherein the non-linear material includes one or more of a mixture of liquids, a solid, a granular material, embedded microspheres, or an emulsion.

  14. Exploring wind energy potential off the California coast

    NASA Astrophysics Data System (ADS)

    Jiang, Qingfang; Doyle, James D.; Haack, Tracy; Dvorak, Michael J.; Archer, Cristina L.; Jacobson, Mark Z.

    2008-10-01

    Wind energy represents the nearest term cost-effective renewable energy source. While efforts have been made to assess wind energy potential over land around the world, offshore wind energy resources are largely unexplored, in part because these regions have relatively sparse wind observations. In this study, the wind energy potential offshore of the California coast is evaluated using a well-tested high-resolution numerical model dataset. We found that along the coastline, the low-level winds exhibit strong spatial variation and are characterized by alternating windspeed maxima and minima near coastal promontories associated with the interaction between the marine boundary layer and coastal topography. Further analysis highlights the enormous and reliable wind energy development potential in these persistent offshore windspeed maxima.

  15. Pattern-formation under acoustic driving forces

    NASA Astrophysics Data System (ADS)

    Valverde, Jose Manuel

    2015-07-01

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

  16. Assessing the Potential for Renewable Energy on Public Lands

    SciTech Connect

    Not Available

    2003-02-01

    This report represents an initial activity of the Bureau of Land Managements (BLM) proposed National Energy Policy Implementation Plan: identify and evaluate renewable energy resources on federal lands and any limitations on accessing them. Ultimately, BLM will prioritize land-use planning activities to increase industrys development of renewable energy resources. These resources include solar, biomass, geothermal, water, and wind energy. To accomplish this, BLM and the Department of Energys National Renewable Energy Laboratory (NREL) established a partnership to conduct an assessment of renewable energy resources on BLM lands in the western United States. The objective of this collaboration was to identify BLM planning units in the western states with the highest potential for private-sector development of renewable resources. The assessment resulted in the following findings: (1) 63 BLM planning units in nine western states have high potential for one or more renewable energy technologies; and (2) 20 BLM planning units in seven western states have high potential for power production from three or more renewable energy sources. This assessment report provides BLM with information needed to prioritize land-use planning activities on the basis of potential for the development of energy from renewable resources.

  17. 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

  18. New approach to calculating the potential energy of colliding nuclei

    SciTech Connect

    Kurmanov, R. S.; Kosenko, G. I.

    2014-12-15

    The differential method proposed by the present authors earlier for the reduction of volume integrals in calculating the potential energy of a compound nucleus is generalized to the case of two interacting nuclei. The Coulomb interaction energy is obtained for the cases of a sharp and a diffuse boundary of nuclei, while the nuclear interaction energy is found only for nuclei with a sharp boundary, the finiteness of the nuclear-force range being taken into account. The present method of calculations permits reducing the time it takes to compute the potential energy at least by two orders of magnitude.

  19. A Frontier orbital energy approach to redox potentials

    NASA Astrophysics Data System (ADS)

    Conradie, Jeanet

    2015-09-01

    The prediction of the oxidation and reduction potentials of molecules is important in many research areas. A review of relationships obtained between frontier orbital energies (eV), the calculated ionization potentials (IP in eV), or adiabatic electron affinities (EA in eV) with the experimental oxidation and reduction potentials is presented, for selected series of β- diketones, rhodium-β-diketonato complexes, as well as metal-tris-β-diketonato complexes, with the metal Fe or Mn. The good linear relationships obtained for related series of complexes show that the oxidation and reduction potentials of these complexes can be predicted by their DFT-calculated energies.

  20. 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 ...

  1. Re-examining Potential for Geothermal Energy in United States

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    New technological initiatives, along with potential policy and economic incentives, could help to bring about a resurgence in geothermal energy development in the United States, said several experts at a 22 May forum in Washington, D.C. The forum was sponsored by the House and Senate Renewable Energy and Energy Efficiency Caucuses, the Sustainable Energy Coalition, and the Environmental and Energy Study Institute. Among these initiatives is an ambitious program of the U.S. Department of Energy to expand existing geothermal energy fields and potentially create new fields through ``enhanced geothermal systems.'' In addition, a program of the Bush administration encourages geothermal development on some public lands, and current legislation would provide tax credits and other incentives for geothermal development.

  2. Biomass energy: the scale of the potential resource.

    PubMed

    Field, Christopher B; Campbell, J Elliott; Lobell, David B

    2008-02-01

    Increased production of biomass for energy has the potential to offset substantial use of fossil fuels, but it also has the potential to threaten conservation areas, pollute water resources and decrease food security. The net effect of biomass energy agriculture on climate could be either cooling or warming, depending on the crop, the technology for converting biomass into useable energy, and the difference in carbon stocks and reflectance of solar radiation between the biomass crop and the pre-existing vegetation. The area with the greatest potential for yielding biomass energy that reduces net warming and avoids competition with food production is land that was previously used for agriculture or pasture but that has been abandoned and not converted to forest or urban areas. At the global scale, potential above-ground plant growth on these abandoned lands has an energy content representing approximately 5% of world primary energy consumption in 2006. The global potential for biomass energy production is large in absolute terms, but it is not enough to replace more than a few percent of current fossil fuel usage. Increasing biomass energy production beyond this level would probably reduce food security and exacerbate forcing of climate change. PMID:18215439

  3. Ab initio Potential Energy Surface for H-H2

    NASA Technical Reports Server (NTRS)

    Partridge, Harry; Bauschlicher, Charles W., Jr.; Stallcop, James R.; Levin, Eugene

    1993-01-01

    Ab initio calculations employing large basis sets are performed to determine an accurate potential energy surface for H-H2 interactions for a broad range of separation distances. At large distances, the spherically averaged potential determined from the calculated energies agrees well with the corresponding results determined from dispersion coefficients; the van der Waals well depth is predicted to be 75 +/- (mu)E(sub h). Large basis sets have also been applied to reexamine the accuracy of theoretical repulsive potential energy surfaces. Multipolar expansions of the computed H-H2 potential energy surface are reported for four internuclear separation distances (1.2, 1.401, 1.449, and 1.7a(sub 0) of the hydrogen molecule. The differential elastic scattering cross section calculated from the present results is compared with the measurements from a crossed beam experiment.

  4. 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.

  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. Potential energy landscapes of elemental and heterogeneous chalcogen clusters

    SciTech Connect

    Mauro, John C.; Loucks, Roger J.; Balakrishnan, Jitendra; Varshneya, Arun K.

    2006-02-15

    We describe the potential energy landscapes of elemental S{sub 8}, Se{sub 8}, and Te{sub 8} clusters using disconnectivity graphs. Inherent structures include both ring and chain configurations, with rings especially dominant in Se{sub 8}. We also map the potential energy landscapes of heterogeneous Se{sub n}(S,Te){sub 8-n} clusters, which offer insights into the structure of heterogeneous chalcogen glasses.

  7. Teaching Potential Energy Functions and Stability with Slap Bracelets

    NASA Astrophysics Data System (ADS)

    Van Hook, Stephen J.

    2005-10-01

    The slap bracelet, an inexpensive child's toy, makes it easy to engage students in hands-on exploration of potential energy curves as well as of stable, unstable, and meta-stable states. Rather than just observing the teacher performing a demonstration, the students can manipulate the equipment themselves and make their own observations, which are then pooled to focus a class discussion on potential energy functions and stability.

  8. Potential production of energy cane for fuel in the Caribbean

    SciTech Connect

    Samuels, G.

    1984-08-01

    Sugarcane grown as energy cane presents a new potential to the Caribbean countries to provide their own energy needs and to reduce or eliminate fuel oil imports. The use of proper agronomic techniques can convert conventional sugarcane growing to a crop capable of giving energy feedstocks in the form of fiber for boiler fuel for electricity and fermentable solids for alcohol for motor fuel. Sugarcane can still be obtained from the energy cane for domestic consumption and export if desired. The aerable land now devoted to sugarcane can utilized for energy-cane production without causing any serious imbalance in food crop production.

  9. The Department of Defense energy vulnerabilities: Potential problems and observations

    NASA Astrophysics Data System (ADS)

    Freiwald, D. A.; Berger, M. E.; Roach, J. F.

    1982-08-01

    The Department of Defense is almost entirely dependent on civilian energy supplies to meet its needs in both peacetime and periods of heightened conflict. There are a number of potential vulnerabilities to the continual and timely supply of energy to both the civilian and military sectors. These include denial of the energy resources themselves, disruption of critical transportation networks, destruction of storage facilities, and interruption of electrical power. This report briefly reviews the present situation for provision of energy from the civilian sector to the military. General vulnerabilities of the existing energy supply system are identified, along with the potential for armed aggression (including terrorist and sabotage activities) against the energy network. Conclusions and some tentative observations are made as to a proper response to the existing vulnerabilities.

  10. DoD energy vulnerabilities: potential problems and observations

    SciTech Connect

    Freiwald, D A; Berger, M E; Roach, J F

    1982-08-01

    The Department of Defense is almost entirely dependent on civilian energy supplies to meet its needs in both peacetime and periods of heightened conflict. There are a number of potential vulnerabilities to the continual and timely supply of energy to both the civilian and military sectors. These include denial of the energy resources themselves, disruption of critical transportation networks, destruction of storage facilities, and interruption of electrical power. This report briefly reviews the present situation for provision of energy from the civilian sector to the military. General vulnerabilities of the existing energy supply system are identified, along with the potential for armed aggression (including terrorist and sabotage activities) against the energy network. Conclusions and some tentative observations are made as to a proper response to the existing vulnerabilities.

  11. Geospatial Analysis of Renewable Energy Technical Potential on Tribal Lands

    SciTech Connect

    Doris, E.; Lopez, A.; Beckley, D.

    2013-02-01

    This technical report uses an established geospatial methodology to estimate the technical potential for renewable energy on tribal lands for the purpose of allowing Tribes to prioritize the development of renewable energy resources either for community scale on-tribal land use or for revenue generating electricity sales.

  12. Gravitational potential as a source of earthquake energy

    USGS Publications Warehouse

    Barrows, L.; Langer, C.J.

    1981-01-01

    Some degree of tectonic stress within the earth originates from gravity acting upon density structures. The work performed by this "gravitational tectonics stress" must have formerly existed as gravitational potential energy contained in the stress-causing density structure. According to the elastic rebound theory (Reid, 1910), the energy of earthquakes comes from an elastic strain field built up by fairly continuous elastic deformation in the period between events. For earthquakes resulting from gravitational tectonic stress, the elastic rebound theory requires the transfer of energy from the gravitational potential of the density structures into an elastic strain field prior to the event. An alternate theory involves partial gravitational collapse of the stress-causing density structures. The earthquake energy comes directly from a net decrease in gravitational potential energy. The gravitational potential energy released at the time of the earthquake is split between the energy released by the earthquake, including work done in the fault zone and an increase in stored elastic strain energy. The stress associated with this elastic strain field should oppose further fault slip. ?? 1981.

  13. Potential geothermal energy applications for Idaho Elks Rehabilitation Hospital

    SciTech Connect

    Austin, J.C.

    1981-11-01

    Several potential applications of geothermal energy for the Idaho Elks Rehabilitation Hospital are outlined. A brief background on the resource and distribution system, is provided; which hospital heating systems should be considered for potential geothermal retrofit is discussed; and technical and economic feasibility are addressed.

  14. Fusion at deep subbarrier energies: potential inversion revisited

    SciTech Connect

    Hagino, K.; Rowley, N.

    2009-03-04

    For a single potential barrier, the barrier penetrability can be inverted based on the WKB approximation to yield the barrier thickness. We apply this method to heavy-ion fusion reactions at energies well below the Coulomb barrier and directly determine the inter-nucleus potential between the colliding nuclei. To this end, we assume that fusion cross sections at deep subbarrier energies are governed by the lowest barrier in the barrier distribution. The inverted inter-nucleus potentials for the {sup 16}O+{sup 144}Sm and {sup 16}O+{sup 208}Pb reactions show that they are much thicker than phenomenological potentials. We discuss a consequence of such thick potential by fitting the inverted potentials with the Bass function.

  15. Saint Paul Energy Park: the potential for district heating

    SciTech Connect

    Lee, C.; Kron, R.; Davis, H.

    1980-03-01

    The results of ANL's study of the energy and economic aspects of using district heating in the St. Paul Energy Park are summarized. The Energy Park is a 6 million ft/sup 2/ residential, commercial office, and light industrial complex to be built in the midway area of St. Paul, Minnesota. Space heating and cooling design loads for the park were calculated assuming that the ASHRAE's 90-75 energy-conserving construction standards would be used in constructing the park's buildings. Based in part on this assumption, ANL estimated the costs and energy use characteristics of six possible energy system options for supplying Energy Park's space heating, space cooling, and domestic hot water heating needs. The results indicate that in today's economy, a central heating and cooling plant with natural gas boilers and electrically driven centrifugal chillers with thermal storage has good potential for energy and economic savings and clearly merits further consideration.

  16. Investigating Energy-Saving Potentials in the Cloud

    PubMed Central

    Lee, Da-Sheng

    2014-01-01

    Collecting webpage messages can serve as a sensor for investigating the energy-saving potential of buildings. Focusing on stores, a cloud sensor system is developed to collect data and determine their energy-saving potential. The owner of a store under investigation must register online, report the store address, area, and the customer ID number on the electric meter. The cloud sensor system automatically surveys the energy usage records by connecting to the power company website and calculating the energy use index (EUI) of the store. Other data includes the chain store check, company capital, location price, and the influence of weather conditions on the store; even the exposure frequency of store under investigation may impact the energy usage collected online. After collecting data from numerous stores, a multi-dimensional data array is constructed to determine energy-saving potential by identifying stores with similarity conditions. Similarity conditions refer to analyzed results that indicate that two stores have similar capital, business scale, weather conditions, and exposure frequency on web. Calculating the EUI difference or pure technical efficiency of stores, the energy-saving potential is determined. In this study, a real case study is performed. An 8-dimensional (8D) data array is constructed by surveying web data related to 67 stores. Then, this study investigated the savings potential of the 33 stores, using a site visit, and employed the cloud sensor system to determine the saving potential. The case study results show good agreement between the data obtained by the site visit and the cloud investigation, with errors within 4.17%. Among 33 the samples, eight stores have low saving potentials of less than 5%. The developed sensor on the cloud successfully identifies them as having low saving potential and avoids wasting money on the site visit. PMID:24561405

  17. Investigating energy-saving potentials in the cloud.

    PubMed

    Lee, Da-Sheng

    2014-01-01

    Collecting webpage messages can serve as a sensor for investigating the energy-saving potential of buildings. Focusing on stores, a cloud sensor system is developed to collect data and determine their energy-saving potential. The owner of a store under investigation must register online, report the store address, area, and the customer ID number on the electric meter. The cloud sensor system automatically surveys the energy usage records by connecting to the power company website and calculating the energy use index (EUI) of the store. Other data includes the chain store check, company capital, location price, and the influence of weather conditions on the store; even the exposure frequency of store under investigation may impact the energy usage collected online. After collecting data from numerous stores, a multi-dimensional data array is constructed to determine energy-saving potential by identifying stores with similarity conditions. Similarity conditions refer to analyzed results that indicate that two stores have similar capital, business scale, weather conditions, and exposure frequency on web. Calculating the EUI difference or pure technical efficiency of stores, the energy-saving potential is determined. In this study, a real case study is performed. An 8-dimensional (8D) data array is constructed by surveying web data related to 67 stores. Then, this study investigated the savings potential of the 33 stores, using a site visit, and employed the cloud sensor system to determine the saving potential. The case study results show good agreement between the data obtained by the site visit and the cloud investigation, with errors within 4.17%. Among 33 the samples, eight stores have low saving potentials of less than 5%. The developed sensor on the cloud successfully identifies them as having low saving potential and avoids wasting money on the site visit. PMID:24561405

  18. Kappa distribution in the presence of a potential energy

    NASA Astrophysics Data System (ADS)

    Livadiotis, George

    2015-02-01

    The present paper develops the theory and formulations of the kappa distributions that describe particle systems characterized by a nonzero potential energy. As yet, kappa distributions were used for the statistical description of the velocity or kinetic energy of particles but not of the potential energy. With the results provided here, it is straightforward to use the developed kappa distributions to describe any particle population of space plasmas subject to a nonnegligible potential energy. Starting from the kappa distribution of the Hamiltonian function, we develop the distributions that describe either the complete phase space or the marginal spaces of positions and velocities. The study shows, among others: (a) The kappa distributions of velocities that describe space plasmas can be vastly different from the standard formulation of the kappa distribution, because of the presence of a potential energy; the correct formulation should be given by the marginal kappa distribution of velocities by integrating the distribution of the Hamiltonian over the potential energy. (b) The long-standing problem of the divergence of the Boltzmannian exponential distribution for bounded radial potentials is solved using kappa distributions of negative kappa index. (c) Anisotropic distributions of velocities can exist in the presence of a velocity-dependent potential. (d) A variety of applications, including derivations/verifications of the following: (i) the Jeans', the most frequent, and the maximum radii in spherical/linear gravitational potentials; (ii) the Virial theorem for power law potentials; (iii) the generalized barometric formula, (iv) the plasma density profiles in Saturnian magnetosphere, and (v) the average electron magnetic moment in Earth's magnetotail.

  19. Giant strain-sensitivity of acoustic energy dissipation in solids containing dry and saturated cracks with wavy interfaces.

    PubMed

    Zaitsev, V Yu; Matveev, L A

    2012-01-01

    Mechanisms of acoustic energy dissipation in heterogeneous solids attract much attention in view of their importance for material characterization, nondestructive testing, and geophysics. Due to the progress in measurement techniques in recent years, it has been revealed that rocks can demonstrate extremely high strain sensitivity of seismoacoustic loss. In particular, it has been found that strains of order 10(-8) produced by lunar and solar tides are capable of causing variations in the seismoacoustic decrement on the order of several percent. Some laboratory data (although obtained for higher frequencies) also indicate the presence of very high dissipative nonlinearity. Conventionally discussed dissipation mechanisms (thermoelastic loss in dry solids, Biot and squirt-type loss in fluid-saturated ones) do not suffice to interpret such data. Here the dissipation at individual cracks is revised taking into account the influence of wavy asperities of their surfaces quite typical of real cracks, which can drastically change the values of the relaxation frequencies and can result in giant strain sensitivity of the dissipation without the necessity of assuming the presence of unrealistically thin (and, therefore, unrealistically soft) cracks. In particular, these mechanisms suggest interpretation for observations of pronounced amplitude modulation of seismo-acoustic waves by tidal strains. PMID:22280566

  20. Acoustic waves from mechanical impulses due to fluorescence resonant energy (Förster) transfer: Blowing a whistle with light

    NASA Astrophysics Data System (ADS)

    Zurita-Sánchez, J. R.; Henkel, C.

    2012-02-01

    We present a momentum transfer mechanism mediated by electromagnetic fields that originates in a system of two nearby molecules: one excited (donor D*) and the other in ground state (acceptor A). An intermolecular force related to fluorescence resonant energy or Förster transfer (FRET) arises in the unstable D*A molecular system, which differs from the equilibrium van der Waals interaction. Due to the its finite lifetime, a mechanical impulse is imparted to the relative motion in the system. We analyze the FRET impulse when the molecules are embedded in free space and find that its magnitude can be much greater than the single recoil photon momentum, getting comparable with the thermal momentum (Maxwell-Boltzmann distribution) at room temperature. In addition, we propose that this FRET impulse can be exploited in the generation of acoustic waves inside a film containing layers of donor and acceptor molecules, when a picosecond laser pulse excites the donors. This acoustic transient is distinguishable from that produced by thermal stress due to laser absorption, and may therefore play a role in photoacoustic spectroscopy. The effect can be seen as exciting a vibrating system like a string or organ pipe with light; it may be used as an opto-mechanical transducer.

  1. Separable representation of energy-dependent optical potentials

    NASA Astrophysics Data System (ADS)

    Hlophe, L.; Elster, Ch.

    2016-03-01

    Background: One important ingredient for many applications of nuclear physics to astrophysics, nuclear energy, and stockpile stewardship are cross sections for reactions of neutrons with rare isotopes. Since direct measurements are often not feasible, indirect methods, e.g., (d ,p ) reactions, should be used. Those (d ,p ) reactions may be viewed as three-body reactions and described with Faddeev techniques. Purpose: Faddeev equations in momentum space have a long tradition of utilizing separable interactions in order to arrive at sets of coupled integral equations in one variable. Optical potentials representing the effective interactions in the neutron (proton) nucleus subsystem are usually non-Hermitian as well as energy dependent. Potential matrix elements as well as transition matrix elements calculated with them must fulfill the reciprocity theorem. The purpose of this paper is to introduce a separable, energy-dependent representation of complex, energy-dependent optical potentials that fulfill reciprocity exactly. Methods: Momentum space Lippmann-Schwinger integral equations are solved with standard techniques to obtain the form factors for the separable representation. Results: Starting from a separable, energy-independent representation of global optical potentials based on a generalization of the Ernst-Shakin-Thaler (EST) scheme, a further generalization is needed to take into account the energy dependence. Applications to n +48Ca ,n +208Pb , and p +208Pb are investigated for energies from 0 to 50 MeV with special emphasis on fulfilling reciprocity. Conclusions: We find that the energy-dependent separable representation of complex, energy-dependent phenomenological optical potentials fulfills reciprocity exactly. In addition, taking into account the explicit energy dependence slightly improves the description of the S matrix elements.

  2. Communication: Separable potential energy surfaces from multiplicative artificial neural networks

    SciTech Connect

    Koch, Werner Zhang, Dong H.

    2014-07-14

    We present a potential energy surface fitting scheme based on multiplicative artificial neural networks. It has the sum of products form required for efficient computation of the dynamics of multidimensional quantum systems with the multi configuration time dependent Hartree method. Moreover, it results in analytic potential energy matrix elements when combined with quantum dynamics methods using Gaussian basis functions, eliminating the need for a local harmonic approximation. Scaling behavior with respect to the complexity of the potential as well as the requested accuracy is discussed.

  3. Framework for State-Level Renewable Energy Market Potential Studies

    SciTech Connect

    Kreycik, C.; Vimmerstedt, L.; Doris, E.

    2010-01-01

    State-level policymakers are relying on estimates of the market potential for renewable energy resources as they set goals and develop policies to accelerate the development of these resources. Therefore, accuracy of such estimates should be understood and possibly improved to appropriately support these decisions. This document provides a framework and next steps for state officials who require estimates of renewable energy market potential. The report gives insight into how to conduct a market potential study, including what supporting data are needed and what types of assumptions need to be made. The report distinguishes between goal-oriented studies and other types of studies, and explains the benefits of each.

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  5. Semi-infinite jellium: Thermodynamic potential, chemical potential, and surface energy

    NASA Astrophysics Data System (ADS)

    Kostrobij, P. P.; Markovych, B. M.

    2015-08-01

    A general expression for the thermodynamic potential of the model of semi-infinite jellium is obtained. By using this expression, the surface energy for the infinite barrier model is calculated. The behavior of the surface energy and of the chemical potential as functions of the Wigner-Seitz radius and the influence of the Coulomb interaction between electrons on the calculated values is studied. It is shown that taking into account the Coulomb interaction between electrons leads to growth of the surface energy. The surface energy is positive in the entire area of the Wigner-Seitz radius. It is shown that taking into account the Coulomb interaction between electrons leads to a decrease of the chemical potential.

  6. Savings potential of ENERGY STAR (registered trademark) voluntary labeling programs

    SciTech Connect

    Webber, Carrie A.; Brown, Richard E.

    1998-06-19

    In 1993 the U.S. Environmental Protection Agency (EPA) introduced ENERGY STAR (registered trademark), a voluntary labeling program designed to identify and promote energy-efficient products. Since then EPA, now in partnership with the U.S. Department of Energy (DOE), has introduced programs for more than twenty products, spanning office equipment, residential heating and cooling equipment, new homes, commercial and residential lighting, home electronics, and major appliances. We present potential energy, dollar and carbon savings forecasts for these programs for the period 1998 to 2010. Our target market penetration case represents our best estimate of future ENERGY STAR savings. It is based on realistic market penetration goals for each of the products. We also provide results under the assumption of 100% market penetration; that is, we assume that all purchasers buy ENERGY STAR-compliant products instead of standard efficiency products throughout the analysis period. Finally, we assess the sensitivity of our target penetration case forecasts to greater or lesser marketing success by EPA and DOE, lower-than-expected future energy prices, and higher or lower rates of carbon emission by electricity generators. The potential savings of ENERGY STAR are substantial. If all purchasers chose Energy Star-compliant products instead of standard efficiency products over the next 15 years, they would save more than $100 billion on their energy bills during those 15 years. (Bill savings are in 1995 dollars, discounted at a 4% real discount rate.)

  7. Solar energy in California industry - Applications, characteristics and potential

    NASA Technical Reports Server (NTRS)

    Barbieri, R. H.; Pivirotto, D. S.

    1978-01-01

    Results of a survey to determine the potential applicability of solar thermal energy to industrial processes in California are presented. It is found that if the heat for all industrial processes at temperatures below 212 F were supplied by solar energy, total state energy consumption could be reduced by 100 trillion Btus (2%), while the use of solar energy in processes between 212 and 350 F could displace 500 trillion Btus. The issues and problems with which solar energy must contend are illustrated by a description of fluid milk processing operations. Solar energy application is found to be technically feasible for processes with thermal energy requirements below 212 F, with design, and degree of technical, economic and management feasibility being site specific. It is recommended that the state provide support for federal and industrial research, development and demonstration programs in order to stimulate acceptance of solar process heat application by industry.

  8. Scenarios of energy demand and efficiency potential for Bulgaria

    SciTech Connect

    Tzvetanov, P.; Ruicheva, M.; Denisiev, M.

    1996-12-31

    The paper presents aggregated results on macroeconomic and final energy demand scenarios developed within the Bulgarian Country Study on Greenhouse Gas Emissions Mitigation, supported by US Country Studies Program. The studies in this area cover 5 main stages: (1) {open_quotes}Baseline{close_quotes} and {open_quotes}Energy Efficiency{close_quotes} socioeconomic and energy policy philosophy; (2) Modeling of macroeconomic and sectoral development till 2020; (3) Expert assessments on the technological options for energy efficiency increase and GHG mitigation in the Production, Transport and Households and Services Sectors; (4) Bottom-up modeling of final energy demand; and (5) Sectoral and overall energy efficiency potential and policy. Within the Bulgarian Country Study, the presented results have served as a basis for the final integration stage {open_quotes}Assessment of the Mitigation Policy and Measures in the Energy System of Bulgaria{close_quotes}.

  9. Calculation of molecular free energies in classical potentials

    NASA Astrophysics Data System (ADS)

    Farhi, Asaf; Singh, Bipin

    2016-02-01

    Free energies of molecules can be calculated by quantum chemistry computations or by normal mode classical calculations. However, the first can be computationally impractical for large molecules and the second is based on the assumption of harmonic dynamics. We present a novel, accurate and complete calculation of molecular free energies in standard classical potentials. In this method we transform the molecule by relaxing potential terms which depend on the coordinates of a group of atoms in that molecule and calculate the free energy difference associated with the transformation. Then, since the transformed molecule can be treated as non-interacting systems, the free energy associated with these atoms is analytically or numerically calculated. This two-step calculation can be applied to calculate free energies of molecules or free energy difference between (possibly large) molecules in a general environment. We demonstrate the method in free energy calculations for methanethiol and butane molecules in vacuum and solvent. We suggest the potential application of free energy calculation of chemical reactions in classical molecular simulations.

  10. Potential for energy conservation in the glass industry

    SciTech Connect

    Garrett-Price, B.A.; Fassbender, A.G.; Bruno, G.A.

    1986-06-01

    While the glass industry (flat glass, container glass, pressed and blown glass, and insulation fiber glass) has reduced its specific energy use (Btu/ton) by almost 30% since 1972, significant potential for further reduction still remains. State-of-the-art technologies are available which could lead to incremental improvements in glass industry energy productivity; however, these technologies must compete for capital with projects undertaken for other reasons (e.g., capacity expansion, equipment rebuild, labor cost reduction, product quality improvement, or compliance with environmental, health or safety regulations). Narrowing profit margins in the large tonnage segments of the glass industry in recent years and the fact that energy costs represent less than 25% of the value added in glass manufacture have combined to impede the widespread adoption of many state-of-the-art conservation technologies. Savings in energy costs alone have not provided the incentive to justify the capital expenditures required to realize the energy savings. Beyond implementation of state-of-the-art technologies, significant potential energy savings could accrue from advanced technologies which represent a radical departure from current glass making technology. Long-term research and development (R and D) programs, which address the technical and economic barriers associated with advanced, energy-conserving technologies, offer the opportunity to realize this energy-saving potential.

  11. Split kinetic energy method for quantum systems with competing potentials

    SciTech Connect

    Mineo, H.; Chao, Sheng D.

    2012-09-15

    For quantum systems with competing potentials, the conventional perturbation theory often yields an asymptotic series and the subsequent numerical outcome becomes uncertain. To tackle such a kind of problems, we develop a general solution scheme based on a new energy dissection idea. Instead of dividing the potential energy into 'unperturbed' and 'perturbed' terms, a partition of the kinetic energy is performed. By distributing the kinetic energy term in part into each individual potential, the Hamiltonian can be expressed as the sum of the subsystem Hamiltonians with respective competing potentials. The total wavefunction is expanded by using a linear combination of the basis sets of respective subsystem Hamiltonians. We first illustrate the solution procedure using a simple system consisting of a particle under the action of double {delta}-function potentials. Next, this method is applied to the prototype systems of a charged harmonic oscillator in strong magnetic field and the hydrogen molecule ion. Compared with the usual perturbation approach, this new scheme converges much faster to the exact solutions for both eigenvalues and eigenfunctions. When properly extended, this new solution scheme can be very useful for dealing with strongly coupling quantum systems. - Highlights: Black-Right-Pointing-Pointer A new basis set expansion method is proposed. Black-Right-Pointing-Pointer Split kinetic energy method is proposed to solve quantum eigenvalue problems. Black-Right-Pointing-Pointer Significant improvement has been obtained in converging to exact results. Black-Right-Pointing-Pointer Extension of such methods is promising and discussed.

  12. Ab Initio Potential Energy Surface for H-H2

    NASA Technical Reports Server (NTRS)

    Patridge, Harry; Bauschlicher, Charles W., Jr.; Stallcop, James R.; Levin, Eugene

    1993-01-01

    Ab initio calculations employing large basis sets are performed to determine an accurate potential energy surface for H-H2 interactions for a broad range of separation distances. At large distances, the spherically averaged potential determined from the calculated energies agrees well with the corresponding results determined from dispersion coefficients; the van der Waals well depth is predicted to be 75 +/- 3 micro E(h). Large basis sets have also been applied to reexamine the accuracy of theoretical repulsive potential energy surfaces (25-70 kcal/mol above the H-H2 asymptote) at small interatomic separations; the Boothroyd, Keogh, Martin, and Peterson (BKMP) potential energy surface is found to agree with results of the present calculations within the expected uncertainty (+/- 1 kcal/mol) of the fit. Multipolar expansions of the computed H-H2 potential energy surface are reported for four internuclear separation distances (1.2, 1.401, 1.449, and 1.7a(0)) of the hydrogen molecule. The differential elastic scattering cross section calculated from the present results is compared with the measurements from a crossed beam experiment.

  13. Generation of thermo-acoustic waves from pulsed solar/IR radiation

    NASA Astrophysics Data System (ADS)

    Rahman, Aowabin

    Acoustic waves could potentially be used in a wide range of engineering applications; however, the high energy consumption in generating acoustic waves from electrical energy and the cost associated with the process limit the use of acoustic waves in industrial processes. Acoustic waves converted from solar radiation provide a feasible way of obtaining acoustic energy, without relying on conventional nonrenewable energy sources. One of the goals of this thesis project was to experimentally study the conversion of thermal to acoustic energy using pulsed radiation. The experiments were categorized into "indoor" and "outdoor" experiments, each with a separate experimental setup. The indoor experiments used an IR heater to power the thermo-acoustic lasers and were primarily aimed at studying the effect of various experimental parameters on the amplitude of sound waves in the low frequency range (below 130 Hz). The IR radiation was modulated externally using a chopper wheel and then impinged on a porous solid, which was housed inside a thermo-acoustic (TA) converter. A microphone located at a certain distance from the porous solid inside the TA converter detected the acoustic signals. The "outdoor" experiments, which were targeted at TA conversion at comparatively higher frequencies (in 200 Hz-3 kHz range) used solar energy to power the thermo-acoustic laser. The amplitudes (in RMS) of thermo-acoustic signals obtained in experiments using IR heater as radiation source were in the 80-100 dB range. The frequency of acoustic waves corresponded to the frequency of interceptions of the radiation beam by the chopper. The amplitudes of acoustic waves were influenced by several factors, including the chopping frequency, magnitude of radiation flux, type of porous material, length of porous material, external heating of the TA converter housing, location of microphone within the air column, and design of the TA converter. The time-dependent profile of the thermo-acoustic signals

  14. Optimizing potential energy functions for maximal intrinsic hyperpolarizability

    SciTech Connect

    Zhou Juefei; Szafruga, Urszula B.; Kuzyk, Mark G.; Watkins, David S.

    2007-11-15

    We use numerical optimization to study the properties of (1) the class of one-dimensional potential energy functions and (2) systems of point nuclei in two dimensions that yield the largest intrinsic hyperpolarizabilities, which we find to be within 30% of the fundamental limit. In all cases, we use a one-electron model. It is found that a broad range of optimized potentials, each of very different character, yield the same intrinsic hyperpolarizability ceiling of 0.709. Furthermore, all optimized potential energy functions share common features such as (1) the value of the normalized transition dipole moment to the dominant state, which forces the hyperpolarizability to be dominated by only two excited states and (2) the energy ratio between the two dominant states. All optimized potentials are found to obey the three-level ansatz to within about 1%. Many of these potential energy functions may be implementable in multiple quantum well structures. The subset of potentials with undulations reaffirm that modulation of conjugation may be an approach for making better organic molecules, though there appear to be many others. Additionally, our results suggest that one-dimensional molecules may have larger diagonal intrinsic hyperpolarizability {beta}{sub xxx}{sup int} than higher-dimensional systems.

  15. Acoustic Noise Test Report for the U.S. Department of Energy 1.5-Megawatt Wind Turbine

    SciTech Connect

    Roadman, Jason; Huskey, Arlinda

    2015-07-01

    A series of tests were conducted to characterize the baseline properties and performance of the U.S. Department of Energy (DOE) 1.5-megawatt wind turbine (DOE 1.5) to enable research model development and quantify the effects of future turbine research modifications. The DOE 1.5 is built on the platform of GE's 1.5-MW SLE commercial wind turbine model. It was installed in a nonstandard configuration at the NWTC with the objective of supporting DOE Wind Program research initiatives such as A2e. Therefore, the test results may not represent the performance capabilities of other GE 1.5-MW SLE turbines. The acoustic noise test documented in this report is one of a series of tests carried out to establish a performance baseline for the DOE 1.5 in the NWTC inflow environment.

  16. [The new technologies for the intraoperative registration of the electrically evoked compound action potentials of the acoustical nerve by means of the neural response telemetry method].

    PubMed

    Bakhshinian, V V; Fedoseev, V I; Tavartkiladze, G A

    2015-01-01

    The present article reports the results of a clinical study of the new wireless device CR120 designed for the intraoperative registration of electrode resistance and the electrically evoked compound action potential (EAP) of the acoustical nerve by means of neural response telemetry. The study has demonstrated the high effectiveness of the application of the new wireless device in clinical practice. It was shown that the registration of electrically evoked compound action potential with the help of the CR120 Intraoperative Remote Assistant took 22% less time than by the conventional method (p<0.001). Moreover, the trial revealed the strong correlation between the threshold EAP values recorded with the use of the new device and by the classical method. PMID:26288202

  17. The WiggleZ Dark Energy Survey: improved distance measurements to z = 1 with reconstruction of the baryonic acoustic feature

    NASA Astrophysics Data System (ADS)

    Kazin, Eyal A.; Koda, Jun; Blake, Chris; Padmanabhan, Nikhil; Brough, Sarah; Colless, Matthew; Contreras, Carlos; Couch, Warrick; Croom, Scott; Croton, Darren J.; Davis, Tamara M.; Drinkwater, Michael J.; Forster, Karl; Gilbank, David; Gladders, Mike; Glazebrook, Karl; Jelliffe, Ben; Jurek, Russell J.; Li, I.-hui; Madore, Barry; Martin, D. Christopher; Pimbblet, Kevin; Poole, Gregory B.; Pracy, Michael; Sharp, Rob; Wisnioski, Emily; Woods, David; Wyder, Ted K.; Yee, H. K. C.

    2014-07-01

    We present significant improvements in cosmic distance measurements from the WiggleZ Dark Energy Survey, achieved by applying the reconstruction of the baryonic acoustic feature technique. We show using both data and simulations that the reconstruction technique can often be effective despite patchiness of the survey, significant edge effects and shot-noise. We investigate three redshift bins in the redshift range 0.2 < z < 1, and in all three find improvement after reconstruction in the detection of the baryonic acoustic feature and its usage as a standard ruler. We measure model-independent distance measures DV(rsfid/rs) of 1716 ± 83, 2221 ± 101, 2516 ± 86 Mpc (68 per cent CL) at effective redshifts z = 0.44, 0.6, 0.73, respectively, where DV is the volume-averaged distance, and rs is the sound horizon at the end of the baryon drag epoch. These significantly improved 4.8, 4.5 and 3.4 per cent accuracy measurements are equivalent to those expected from surveys with up to 2.5 times the volume of WiggleZ without reconstruction applied. These measurements are fully consistent with cosmologies allowed by the analyses of the Planck Collaboration and the Sloan Digital Sky Survey. We provide the DV(rsfid/rs) posterior probability distributions and their covariances. When combining these measurements with temperature fluctuations measurements of Planck, the polarization of Wilkinson Microwave Anisotropy Probe 9, and the 6dF Galaxy Survey baryonic acoustic feature, we do not detect deviations from a flat Λ cold dark matter (ΛCDM) model. Assuming this model, we constrain the current expansion rate to H0 = 67.15 ± 0.98 km s-1Mpc-1. Allowing the equation of state of dark energy to vary, we obtain wDE = -1.080 ± 0.135. When assuming a curved ΛCDM model we obtain a curvature value of ΩK = -0.0043 ± 0.0047.

  18. Warm Body Temperature Facilitates Energy Efficient Cortical Action Potentials

    PubMed Central

    Yu, Yuguo; Hill, Adam P.; McCormick, David A.

    2012-01-01

    The energy efficiency of neural signal transmission is important not only as a limiting factor in brain architecture, but it also influences the interpretation of functional brain imaging signals. Action potential generation in mammalian, versus invertebrate, axons is remarkably energy efficient. Here we demonstrate that this increase in energy efficiency is due largely to a warmer body temperature. Increases in temperature result in an exponential increase in energy efficiency for single action potentials by increasing the rate of Na+ channel inactivation, resulting in a marked reduction in overlap of the inward Na+, and outward K+, currents and a shortening of action potential duration. This increase in single spike efficiency is, however, counterbalanced by a temperature-dependent decrease in the amplitude and duration of the spike afterhyperpolarization, resulting in a nonlinear increase in the spike firing rate, particularly at temperatures above approximately 35°C. Interestingly, the total energy cost, as measured by the multiplication of total Na+ entry per spike and average firing rate in response to a constant input, reaches a global minimum between 37–42°C. Our results indicate that increases in temperature result in an unexpected increase in energy efficiency, especially near normal body temperature, thus allowing the brain to utilize an energy efficient neural code. PMID:22511855

  19. Wind energy potential analysis in Al-Fattaih-Darnah

    NASA Astrophysics Data System (ADS)

    Tjahjana, Dominicus Danardono Dwi Prija; Salem, Abdelkarim Ali; Himawanto, Dwi Aries

    2016-03-01

    In this paper the wind energy potential in Al-Fattaih-Darnah, Libya, had been studied. Wind energy is very attractive because it can provide a clean and renewable energy. Due mostly to the uncertainty caused by the chaotic characteristics of wind near the earth's surface, wind energy characteristic need to be investigated carefully in order to get consistent power generation. This investigation was based on one year wind data measured in 2003. As a result of the analysis, wind speed profile and wind energy potential have been developed. The wind energy potential of the location is looked very promising to generate electricity. The annual wind speed of the site is 8.21 m/s and the wind speed carrying maximum energy is 7.97 m/s. The annual power density of the site is classified into class 3. The Polaris P50-500 wind turbine can produce 768.39 M Wh/year and has capacity factor of 17.54%.

  20. 4-D imaging of seepage in earthen embankments with time-lapse inversion of self-potential data constrained by acoustic emissions localization

    NASA Astrophysics Data System (ADS)

    Rittgers, J. B.; Revil, A.; Planes, T.; Mooney, M. A.; Koelewijn, A. R.

    2015-02-01

    New methods are required to combine the information contained in the passive electrical and seismic signals to detect, localize and monitor hydromechanical disturbances in porous media. We propose a field experiment showing how passive seismic and electrical data can be combined together to detect a preferential flow path associated with internal erosion in a Earth dam. Continuous passive seismic and electrical (self-potential) monitoring data were recorded during a 7-d full-scale levee (earthen embankment) failure test, conducted in Booneschans, Netherlands in 2012. Spatially coherent acoustic emissions events and the development of a self-potential anomaly, associated with induced concentrated seepage and internal erosion phenomena, were identified and imaged near the downstream toe of the embankment, in an area that subsequently developed a series of concentrated water flows and sand boils, and where liquefaction of the embankment toe eventually developed. We present a new 4-D grid-search algorithm for acoustic emissions localization in both time and space, and the application of the localization results to add spatially varying constraints to time-lapse 3-D modelling of self-potential data in the terms of source current localization. Seismic signal localization results are utilized to build a set of time-invariant yet spatially varying model weights used for the inversion of the self-potential data. Results from the combination of these two passive techniques show results that are more consistent in terms of focused ground water flow with respect to visual observation on the embankment. This approach to geophysical monitoring of earthen embankments provides an improved approach for early detection and imaging of the development of embankment defects associated with concentrated seepage and internal erosion phenomena. The same approach can be used to detect various types of hydromechanical disturbances at larger scales.

  1. Saturation wind power potential and its implications for wind energy.

    PubMed

    Jacobson, Mark Z; Archer, Cristina L

    2012-09-25

    Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams. Thus, there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world's all-purpose power from wind in a 2030 clean-energy economy. PMID:23019353

  2. Communication: Fitting potential energy surfaces with fundamental invariant neural network.

    PubMed

    Shao, Kejie; Chen, Jun; Zhao, Zhiqiang; Zhang, Dong H

    2016-08-21

    A more flexible neural network (NN) method using the fundamental invariants (FIs) as the input vector is proposed in the construction of potential energy surfaces for molecular systems involving identical atoms. Mathematically, FIs finitely generate the permutation invariant polynomial (PIP) ring. In combination with NN, fundamental invariant neural network (FI-NN) can approximate any function to arbitrary accuracy. Because FI-NN minimizes the size of input permutation invariant polynomials, it can efficiently reduce the evaluation time of potential energy, in particular for polyatomic systems. In this work, we provide the FIs for all possible molecular systems up to five atoms. Potential energy surfaces for OH3 and CH4 were constructed with FI-NN, with the accuracy confirmed by full-dimensional quantum dynamic scattering and bound state calculations. PMID:27544080

  3. Saturation wind power potential and its implications for wind energy

    PubMed Central

    Jacobson, Mark Z.; Archer, Cristina L.

    2012-01-01

    Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams. Thus, there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world’s all-purpose power from wind in a 2030 clean-energy economy. PMID:23019353

  4. 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.

  5. 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

  6. Acoustic energy density distribution and sound intensity vector field inside coupled spaces.

    PubMed

    Meissner, Mirosław

    2012-07-01

    In this paper, the modal expansion method supported by a computer implementation has been used to predict steady-state distributions of the potential and kinetic energy densities, and the active and reactive sound intensities inside two coupled enclosures. The numerical study was dedicated to low-frequency room responses. Calculation results have shown that the distribution of energetic quantities in coupled spaces is strongly influenced by the modal localization. Appropriate descriptors of the localization effect were introduced to identify localized modes. As was evidenced by numerical data, the characteristic objects in the active intensity field are vortices positioned irregularly inside the room. It was found that vortex centers lie exactly on the lines corresponding to zeros of the eigenfunction for a dominant mode. Finally, an impact of the wall impedance on the quantitative relationship between the active and reactive intensities was analyzed and it was concluded that for very small sound damping the behavior of the sound intensity inside the room space is essentially only oscillatory. PMID:22779472

  7. Potential function and dissociation energy of alkali halide

    NASA Astrophysics Data System (ADS)

    Srivastava, Abhay P.; Pandey, Anjani K.; Pandey, Brijesh K.

    2016-05-01

    Dissociation energy of some alkali halides have been calculated by using different interaction potential function such as Born-Mayer, Varshani-Shukla and L5 potential model. The theoretical calculation is compared with experimental values. The Result shows that the values of dissociation energy as calculated by using different potential models have an equal amount of deviation with experimental values. The above said deviation with experimental values can be explained by consideration of rotational-vibrational coupling between the constituents of molecules in the limelight of molecular spectroscopy. Findings of present work suggest that the existing potential model need to be reviewed in view of the correction factors solely depending on the rotational, vibrational and electronic coupling between the constituents of molecules.

  8. An adaptive interpolation scheme for molecular potential energy surfaces.

    PubMed

    Kowalewski, Markus; Larsson, Elisabeth; Heryudono, Alfa

    2016-08-28

    The calculation of potential energy surfaces for quantum dynamics can be a time consuming task-especially when a high level of theory for the electronic structure calculation is required. We propose an adaptive interpolation algorithm based on polyharmonic splines combined with a partition of unity approach. The adaptive node refinement allows to greatly reduce the number of sample points by employing a local error estimate. The algorithm and its scaling behavior are evaluated for a model function in 2, 3, and 4 dimensions. The developed algorithm allows for a more rapid and reliable interpolation of a potential energy surface within a given accuracy compared to the non-adaptive version. PMID:27586901

  9. Finding reaction paths using the potential energy as reaction coordinate.

    PubMed

    Aguilar-Mogas, Antoni; Giménez, Xavier; Bofill, Josep Maria

    2008-03-14

    The intrinsic reaction coordinate curve (IRC), normally proposed as a representation of a reaction path, is parametrized as a function of the potential energy rather than the arc-length. This change in the parametrization of the curve implies that the values of the energy of the potential energy surface points, where the IRC curve is located, play the role of reaction coordinate. We use Caratheodory's relation to derive in a rigorous manner the proposed parametrization of the IRC path. Since this Caratheodory's relation is the basis of the theory of calculus of variations, then this fact permits to reformulate the IRC model from this mathematical theory. In this mathematical theory, the character of the variational solution (either maximum or minimum) is given through the Weierstrass E-function. As proposed by Crehuet and Bofill [J. Chem. Phys. 122, 234105 (2005)], we use the minimization of the Weierstrass E-function, as a function of the potential energy, to locate an IRC path between two minima from an arbitrary curve on the potential energy surface, and then join these two minima. We also prove, from the analysis of the Weierstrass E-function, the mathematical bases for the algorithms proposed to locate the IRC path. The proposed algorithm is applied to a set of examples. Finally, the algorithm is used to locate a discontinuous, or broken, IRC path, namely, when the path connects two first order saddle points through a valley-ridged inflection point. PMID:18345872

  10. Finding reaction paths using the potential energy as reaction coordinate

    NASA Astrophysics Data System (ADS)

    Aguilar-Mogas, Antoni; Giménez, Xavier; Bofill, Josep Maria

    2008-03-01

    The intrinsic reaction coordinate curve (IRC), normally proposed as a representation of a reaction path, is parametrized as a function of the potential energy rather than the arc-length. This change in the parametrization of the curve implies that the values of the energy of the potential energy surface points, where the IRC curve is located, play the role of reaction coordinate. We use Carathéodory's relation to derive in a rigorous manner the proposed parametrization of the IRC path. Since this Carathéodory's relation is the basis of the theory of calculus of variations, then this fact permits to reformulate the IRC model from this mathematical theory. In this mathematical theory, the character of the variational solution (either maximum or minimum) is given through the Weierstrass E-function. As proposed by Crehuet and Bofill [J. Chem. Phys. 122, 234105 (2005)], we use the minimization of the Weierstrass E-function, as a function of the potential energy, to locate an IRC path between two minima from an arbitrary curve on the potential energy surface, and then join these two minima. We also prove, from the analysis of the Weierstrass E-function, the mathematical bases for the algorithms proposed to locate the IRC path. The proposed algorithm is applied to a set of examples. Finally, the algorithm is used to locate a discontinuous, or broken, IRC path, namely, when the path connects two first order saddle points through a valley-ridged inflection point.

  11. Potential structural material problems in a hydrogen energy system

    NASA Technical Reports Server (NTRS)

    Gray, H. R.; Nelson, H. G.; Johnson, R. E.; Mcpherson, W. B.; Howard, F. S.; Swisher, J. H.

    1976-01-01

    Potential structural material problems that may be encountered in the three components of a hydrogen energy system - production, transmission/storage, and utilization - have been identified. Hydrogen embrittlement, corrosion, oxidation, and erosion may occur during the production of hydrogen. Hydrogen embrittlement is of major concern during both transmission and utilization of hydrogen. Specific materials research and development programs necessary to support a hydrogen energy system are described. An awareness of probable shortages of strategic materials has been maintained in these suggested programs.

  12. Reference pressure changes and available potential energy in isobaric coordinates

    NASA Technical Reports Server (NTRS)

    Robertson, F. R.

    1985-01-01

    A formulation of the available potential energy (APE) equation in isobaric coordinates which alleviates the need for computing temporal derivatives of reference pressure and describes how work done relates to changes in the APE of a limited region is presented. The APE budget equation possesses terms analogous to those in Johnson's (1970) isentropic version. It is shown that APE changes result from either mechanical work inside the domain or an exchange of energy via boundary processes with the surrounding environment.

  13. Potential structural material problems in a hydrogen energy system

    NASA Technical Reports Server (NTRS)

    Gray, H. R.; Nelson, H. G.; Johnson, R. E.; Mcpherson, B.; Howard, F. S.; Swisher, J. H.

    1975-01-01

    Potential structural material problems that may be encountered in the three components of a hydrogen energy system - production, transmission/storage, and utilization - were identified. Hydrogen embrittlement, corrosion, oxidation, and erosion may occur during the production of hydrogen. Hydrogen embrittlement is of major concern during both transmission and utilization of hydrogen. Specific materials research and development programs necessary to support a hydrogen energy system are described.

  14. 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. ...

  15. Renewable energy technologies adoption in Kazakhstan: potentials, barriers and solutions

    NASA Astrophysics Data System (ADS)

    Karatayev, Marat; Marazza, Diego; Contin, Andrea

    2015-04-01

    The growth in environmental pollution alongside an increasing demand for electricity in Kazakhstan calls for a higher level of renewable energy penetration into national power systems. Kazakhstan has great potential for renewable energies from wind, solar, hydro and biomass resources that can be exploited for electricity production. In 2013, the Kazakhstani Ministry of Energy initiated a new power development plan, which aims to bring the share of renewable energy to 3% by 2020 rising to 30% by 2030 and 50% by 2050. The current contribution of renewable energy resources in the national electricity mix, however, is less than 1%. As a developing country, Kazakhstan has faced a number of barriers to increase renewable energy use, which have to be analysed and translated into a comprehensive renewable energy policy framework. This study presents an overview of the current conditions of renewable energy development in Kazakhstan. Secondly, it identifies and describes the main barriers that prevent diffusion of renewable energy technologies in Kazakhstan. Finally, the paper provides solutions to overcome specific barriers in order to successfully develop a renewable energy technology sector in Kazakhstan.

  16. Energy savings potential in air conditioners and chiller systems

    SciTech Connect

    Kaya, Durmus; Alidrisi, Hisham

    2014-01-22

    In the current paper we quantified and evaluated the energy saving potential in air conditioners and chiller systems. Here, we also showed how to reduce the cost of air conditioners and chiller systems in existing facilities on the basis of payback periods. Among the measures investigated were: (1) installing higher efficiency air conditioners, (2) installing higher efficiency chillers, (3) duty cycling air conditioning units, and (4) utilizing existing economizers on air conditioning units. For each method, examples were provided from Arizona, USA. In these examples, the amount of saved energy, the financial evaluation of this energy, and the investment cost and pay back periods were calculated.

  17. LHC Physics Potential vs. Energy: Considerations for the 2011 Run

    SciTech Connect

    Quigg, Chris; /Fermilab /CERN

    2011-02-01

    Parton luminosities are convenient for estimating how the physics potential of Large Hadron Collider experiments depends on the energy of the proton beams. I quantify the advantage of increasing the beam energy from 3.5 TeV to 4 TeV. I present parton luminosities, ratios of parton luminosities, and contours of fixed parton luminosity for gg, u {bar d}, qq, and gq interactions over the energy range relevant to the Large Hadron Collider, along with example analyses for specific processes. This note extends the analysis presented in Ref. [1]. Full-size figures are available as pdf files at lutece.fnal.gov/PartonLum11/.

  18. Energy savings potential in air conditioners and chiller systems

    DOE PAGESBeta

    Kaya, Durmus; Alidrisi, Hisham

    2014-01-22

    In the current paper we quantified and evaluated the energy saving potential in air conditioners and chiller systems. Here, we also showed how to reduce the cost of air conditioners and chiller systems in existing facilities on the basis of payback periods. Among the measures investigated were: (1) installing higher efficiency air conditioners, (2) installing higher efficiency chillers, (3) duty cycling air conditioning units, and (4) utilizing existing economizers on air conditioning units. For each method, examples were provided from Arizona, USA. In these examples, the amount of saved energy, the financial evaluation of this energy, and the investment costmore » and pay back periods were calculated.« less

  19. Polariton Condensation in Dynamic Acoustic Lattices

    NASA Astrophysics Data System (ADS)

    Cerda-Méndez, E. A.; Krizhanovskii, D. N.; Wouters, M.; Bradley, R.; Biermann, K.; Guda, K.; Hey, R.; Santos, P. V.; Sarkar, D.; Skolnick, M. S.

    2010-09-01

    We demonstrate that the tunable potential introduced by a surface acoustic wave on a homogeneous polariton condensate leads to fragmentation of the condensate into an array of wires which move with the acoustic velocity. Reduction of the spatial coherence of the condensate emission along the surface acoustic wave direction is attributed to the suppression of coupling between the spatially modulated condensates. Interparticle interactions observed at high polariton densities screen the acoustic potential, partially reversing its effect on spatial coherence.

  20. A hybrid approach for predicting the distribution of vibro-acoustic energy in complex built-up structures.

    PubMed

    Maksimov, Dmitrii N; Tanner, Gregor

    2011-09-01

    Finding the distribution of vibro-acoustic energy in complex built-up structures in the mid-to-high frequency regime is a difficult task. In particular, structures with large variation of local wavelengths and/or characteristic scales pose a challenge referred to as the mid-frequency problem. Standard numerical methods such as the finite element method (FEM) scale with the local wavelength and quickly become too large even for modern computer architectures. High frequency techniques, such as statistical energy analysis (SEA), often miss important information such as dominant resonance behavior due to stiff or small scale parts of the structure. Hybrid methods circumvent this problem by coupling FEM/BEM and SEA models in a given built-up structure. In the approach adopted here, the whole system is split into a number of subsystems that are treated by either FEM or SEA depending on the local wavelength. Subsystems with relative long wavelengths are modeled using FEM. Making a diffuse field assumption for the wave fields in the short wave length components, the coupling between subsystems can be reduced to a weighted random field correlation function. The approach presented results in an SEA-like set of linear equations that can be solved for the mean energies in the short wavelength subsystems. PMID:21895075

  1. RELEASE OF ELASTIC STRAIN ENERGY AS ACOUSTIC EMISSION DURING THE REVERSE THERMOELASTIC PHASE TRANSFORMATION IN Au-47.5 at.percent Cd ALLOY

    SciTech Connect

    Baram, J.; Avissar, J.; Gefen, Y.; Rosen, M.

    1980-05-01

    The objective of this paper is to present experimental evidence concerning the acoustic energy evolved during the heating and cooling phase changes in Au-47.5 at.% Cd polycrystals. The results are examined from the point of view of the stored elastic strain energy during the martensite formation, and the frictional work that is dissipated by the movement of martensite interfaces in either direction, upon heating and cooling.

  2. Pseudospectral Gaussian quantum dynamics: Efficient sampling of potential energy surfaces

    NASA Astrophysics Data System (ADS)

    Heaps, Charles W.; Mazziotti, David A.

    2016-04-01

    Trajectory-based Gaussian basis sets have been tremendously successful in describing high-dimensional quantum molecular dynamics. In this paper, we introduce a pseudospectral Gaussian-based method that achieves accurate quantum dynamics using efficient, real-space sampling of the time-dependent basis set. As in other Gaussian basis methods, we begin with a basis set expansion using time-dependent Gaussian basis functions guided by classical mechanics. Unlike other Gaussian methods but characteristic of the pseudospectral and collocation methods, the basis set is tested with N Dirac delta functions, where N is the number of basis functions, rather than using the basis function as test functions. As a result, the integration for matrix elements is reduced to function evaluation. Pseudospectral Gaussian dynamics only requires O ( N ) potential energy calculations, in contrast to O ( N 2 ) evaluations in a variational calculation. The classical trajectories allow small basis sets to sample high-dimensional potentials. Applications are made to diatomic oscillations in a Morse potential and a generalized version of the Henon-Heiles potential in two, four, and six dimensions. Comparisons are drawn to full analytical evaluation of potential energy integrals (variational) and the bra-ket averaged Taylor (BAT) expansion, an O ( N ) approximation used in Gaussian-based dynamics. In all cases, the pseudospectral Gaussian method is competitive with full variational calculations that require a global, analytical, and integrable potential energy surface. Additionally, the BAT breaks down when quantum mechanical coherence is particularly strong (i.e., barrier reflection in the Morse oscillator). The ability to obtain variational accuracy using only the potential energy at discrete points makes the pseudospectral Gaussian method a promising avenue for on-the-fly dynamics, where electronic structure calculations become computationally significant.

  3. Pseudospectral Gaussian quantum dynamics: Efficient sampling of potential energy surfaces.

    PubMed

    Heaps, Charles W; Mazziotti, David A

    2016-04-28

    Trajectory-based Gaussian basis sets have been tremendously successful in describing high-dimensional quantum molecular dynamics. In this paper, we introduce a pseudospectral Gaussian-based method that achieves accurate quantum dynamics using efficient, real-space sampling of the time-dependent basis set. As in other Gaussian basis methods, we begin with a basis set expansion using time-dependent Gaussian basis functions guided by classical mechanics. Unlike other Gaussian methods but characteristic of the pseudospectral and collocation methods, the basis set is tested with N Dirac delta functions, where N is the number of basis functions, rather than using the basis function as test functions. As a result, the integration for matrix elements is reduced to function evaluation. Pseudospectral Gaussian dynamics only requires O(N) potential energy calculations, in contrast to O(N(2)) evaluations in a variational calculation. The classical trajectories allow small basis sets to sample high-dimensional potentials. Applications are made to diatomic oscillations in a Morse potential and a generalized version of the Henon-Heiles potential in two, four, and six dimensions. Comparisons are drawn to full analytical evaluation of potential energy integrals (variational) and the bra-ket averaged Taylor (BAT) expansion, an O(N) approximation used in Gaussian-based dynamics. In all cases, the pseudospectral Gaussian method is competitive with full variational calculations that require a global, analytical, and integrable potential energy surface. Additionally, the BAT breaks down when quantum mechanical coherence is particularly strong (i.e., barrier reflection in the Morse oscillator). The ability to obtain variational accuracy using only the potential energy at discrete points makes the pseudospectral Gaussian method a promising avenue for on-the-fly dynamics, where electronic structure calculations become computationally significant. PMID:27131532

  4. Potentials and policy implications of energy and material efficiency improvement

    SciTech Connect

    Worrell, Ernst; Levine, Mark; Price, Lynn; Martin, Nathan; van den Broek, Richard; Block, Kornelis

    1997-01-01

    There is a growing awareness of the serious problems associated with the provision of sufficient energy to meet human needs and to fuel economic growth world-wide. This has pointed to the need for energy and material efficiency, which would reduce air, water and thermal pollution, as well as waste production. Increasing energy and material efficiency also have the benefits of increased employment, improved balance of imports and exports, increased security of energy supply, and adopting environmentally advantageous energy supply. A large potential exists for energy savings through energy and material efficiency improvements. Technologies are not now, nor will they be, in the foreseeable future, the limiting factors with regard to continuing energy efficiency improvements. There are serious barriers to energy efficiency improvement, including unwillingness to invest, lack of available and accessible information, economic disincentives and organizational barriers. A wide range of policy instruments, as well as innovative approaches have been tried in some countries in order to achieve the desired energy efficiency approaches. These include: regulation and guidelines; economic instruments and incentives; voluntary agreements and actions, information, education and training; and research, development and demonstration. An area that requires particular attention is that of improved international co-operation to develop policy instruments and technologies to meet the needs of developing countries. Material efficiency has not received the attention that it deserves. Consequently, there is a dearth of data on the qualities and quantities for final consumption, thus, making it difficult to formulate policies. Available data, however, suggest that there is a large potential for improved use of many materials in industrialized countries.

  5. Teaching Field Concept and Potential Energy at A-Level.

    ERIC Educational Resources Information Center

    Poon, C. H.

    1986-01-01

    Argues for a greater emphasis on the reality of fields in electronics and gravitation instruction. Advocates that the potential energy in a system be regarded as stored in the field rather than in the material bodies of the system. Provides a rationale and examples for this position. (ML)

  6. High energy scattering of Dirac particles on smooth potentials

    NASA Astrophysics Data System (ADS)

    Han, Nguyen Suan; Dung, Le Anh; Xuan, Nguyen Nhu; Thang, Vu Toan

    2016-08-01

    The derivation of the Glauber type representation for the high energy scattering amplitude of particles of spin 1/2 is given within the framework of the Dirac equation in the Foldy-Wouthuysen (FW) representation and two-component formalism. The differential cross-sections on the Yukawa and Gaussian potentials are also considered and discussed.

  7. Unified Technical Concepts. Module 7: Potential and Kinetic Energy.

    ERIC Educational Resources Information Center

    Technical Education Research Center, Waco, TX.

    This concept module on potential and kinetic energy is one of thirteen modules that provide a flexible, laboratory-based physics instructional package designed to meet the specialized needs of students in two-year, postsecondary technical schools. Each of the thirteen concept modules discusses a single physics concept and how it is applied to each…

  8. Global Potential of Energy Efficiency Standards and Labeling Programs

    SciTech Connect

    McNeil, Michael A; McNeil, Michael A.; Letschert, Virginie; de la Rue du Can, Stephane

    2008-06-15

    This report estimates the global potential reductions in greenhouse gas emissions by 2030 for energy efficiency improvements associated with equipment (appliances, lighting, and HVAC) in buildings by means of energy efficiency standards and labels (EES&L). A consensus has emerged among the world's scientists and many corporate and political leaders regarding the need to address the threat of climate change through emissions mitigation and adaptation. A further consensus has emerged that a central component of these strategies must be focused around energy, which is the primary generator of greenhouse gas emissions. Two important questions result from this consensus: 'what kinds of policies encourage the appropriate transformation to energy efficiency' and 'how much impact can these policies have'? This report aims to contribute to the dialogue surrounding these issues by considering the potential impacts of a single policy type, applied on a global scale. The policy addressed in this report is Energy Efficient Standards and Labeling (EES&L) for energy-consuming equipment, which has now been implemented in over 60 countries. Mandatory energy performance standards are important because they contribute positively to a nation's economy and provide relative certainty about the outcome (both timing and magnitudes). Labels also contribute positively to a nation's economy and importantly increase the awareness of the energy-consuming public. Other policies not analyzed here (utility incentives, tax credits) are complimentary to standards and labels and also contribute in significant ways to reducing greenhouse gas emissions. We believe the analysis reported here to be the first systematic attempt to evaluate the potential of savings from EES&L for all countries and for such a large set of products. The goal of the analysis is to provide an assessment that is sufficiently well-quantified and accurate to allow comparison and integration with other strategies under

  9. Marine bioacoustics and technology: The new world of marine acoustic ecology

    NASA Astrophysics Data System (ADS)

    Hastings, Mardi C.; Au, Whitlow W. L.

    2012-11-01

    Marine animals use sound for communication, navigation, predator avoidance, and prey detection. Thus the rise in acoustic energy associated with increasing human activity in the ocean has potential to impact the lives of marine animals. Thirty years ago marine bioacoustics primarily focused on evaluating effects of human-generated sound on hearing and behavior by testing captive animals and visually observing wild animals. Since that time rapidly changing electronic and computing technologies have yielded three tools that revolutionized how bioacousticians study marine animals. These tools are (1) portable systems for measuring electrophysiological auditory evoked potentials, (2) miniaturized tags equipped with positioning sensors and acoustic recording devices for continuous short-term acoustical observation rather than intermittent visual observation, and (3) passive acoustic monitoring (PAM) systems for remote long-term acoustic observations at specific locations. The beauty of these breakthroughs is their direct applicability to wild animals in natural habitats rather than only to animals held in captivity. Hearing capabilities of many wild species including polar bears, beaked whales, and reef fishes have now been assessed by measuring their auditory evoked potentials. Miniaturized acoustic tags temporarily attached to an animal to record its movements and acoustic environment have revealed the acoustic foraging behavior of sperm and beaked whales. Now tags are being adapted to fishes in effort to understand their behavior in the presence of noise. Moving and static PAM systems automatically detect and characterize biological and physical features of an ocean area without adding any acoustic energy to the environment. PAM is becoming a powerful technique for understanding and managing marine habitats. This paper will review the influence of these transformative tools on the knowledge base of marine bioacoustics and elucidation of relationships between marine

  10. Energy trapping of thickness-extensional modes in thin film bulk acoustic wave filters

    NASA Astrophysics Data System (ADS)

    Zhao, Zinan; Qian, Zhenghua; Wang, Bin

    2016-01-01

    This paper presents the thickness-extensional vibration of a rectangular piezoelectric thin film bulk acoustic wave filter with two pairs of electrodes symmetrically deposited on the center of the zinc oxide film. The two-dimensional scalar differential equations which were first derived to describe in-plane vibration distribution by Tiersten and Stevens are employed. The Ritz method with trigonometric functions as basis functions is used based on a variational formulation developed in our previous paper. Free vibration resonant frequencies and corresponding modes are obtained. The modes may separate into symmetric and antisymmetric ones for such a structurally symmetric filter. Trapped modes with vibrations mainly under the driving electrodes are exhibited. The six corner-type regions of the filter neglected by Tiersten and Stevens for an approximation are taken into account in our analysis. Results show that their approximation can lead to an inaccuracy on the order of dozens of ppm for the fundamental mode, which is quite significant in filter operation and application.

  11. Understanding Potential Climate Variability Impacts on the Offshore Energy Industry

    NASA Astrophysics Data System (ADS)

    Stear, J.

    2014-12-01

    Climate variability may have important implications for the offshore energy industry. Scenarios of increased storm activity and changes in sea level could require the retrofit of existing offshore platforms and coastal infrastructure, the decommissioning of facilities for which upgrade or relocation is not economically viable, and the development of new methods and equipment which are removed from or less sensitive to environmental loads. Over the past years the energy industry has been actively involved in collaborative research efforts with government and academia to identify the potential changes in the offshore operating environment, and corresponding risk implications. This presentation will review several of these efforts, and for several of the hypothetical climate variation scenarios, review the potential impacts on and possible mitigations for offshore and coastal energy infrastructure and operations.

  12. Contrastive studies of potential energy functions of some diatomic molecules

    NASA Astrophysics Data System (ADS)

    Abdallah, Hassan H.; Abdullah, Hewa Y.

    2016-03-01

    It was proposed that iron hydride, FeH, would be formed only on grains at the clouds through the reaction of the adsorbed H atoms or H2 molecules with the adsorbed Fe atoms on the grains. The importance of FeH in Astrophysics presents an additional motivation to study its energetic, spectroscopic constants and Potential Energy Curves. The structural optimization for ground state of FeH was calculated by different theoretical methods, namely, Hartree-Fock (HF), the density functional theory (DFT), B3LYP, MP2 method and QCISD(T) methods and compared with available data from the literature. The single ionized forms, cation and anion, were also obtained at the same level of calculations. Charges, dipole moment, geometrical parameters, molecular orbital energies and spectroscopic parameters were calculated and reported. In addition, the molecular ionization potential, electron affinity and dissociation energy were investigated.

  13. Three-dimensional potential energy surface of Ar–CO

    SciTech Connect

    Sumiyoshi, Yoshihiro; Endo, Yasuki

    2015-01-14

    A three-dimensional intermolecular potential energy surface of the Ar–CO complex has been determined by fitting most of the previously reported spectroscopic data, where observed transition frequencies by microwave, millimeter-wave, submillimeter-wave, and infrared spectroscopy were reproduced simultaneously within their experimental accuracies. A free rotor model Hamiltonian considering all the freedom of motions for an atom-diatom system was applied to calculate vibration-rotation energies. A three-dimensional potential energy surface obtained by ab initio calculations at the CCSD(T)-F12b/aug-cc-pV5Z level of theory was parameterized by a model function consisting of 46 parameters. They were used as initial values for the least-squares analysis of the experimental data. A total of 20 parameters were optimized to reproduce all the spectroscopic data.

  14. Global interior eddy available potential energy diagnosed from Argo floats

    NASA Astrophysics Data System (ADS)

    Roullet, Guillaume; Capet, Xavier; Maze, Guillaume

    2014-03-01

    By combining all Argo profiles for the period 2002 to present, a cumulative density function is constructed on a 3-D grid of the global ocean. This function quantifies the statistics of isopycnals: time-averaged density, root-mean square of isopycnal displacement, and eddy available potential energy (EAPE). EAPE is the analogue of the eddy kinetic energy, but for the potential energy reservoir. Because it is essentially tied to the spatial structure and magnitude of mesoscale activity, EAPE is an important quantity that should be useful to evaluate eddy resolving/permitting model turbulence and circulation. Among other striking features are the turbulent behavior of Pacific and southern Atlantic Tsuchiya jets and subsurface EAPE maxima in some parts of the ocean, particularly in the Southern Ocean.

  15. Heterobarrier for converting hot-phonon energy to electric potential

    NASA Astrophysics Data System (ADS)

    Shin, Seungha; Melnick, Corey; Kaviany, Massoud

    2013-02-01

    We show that hot phonons emitted in energy conversion or resistive processes can be converted to electric potential in heterobarrier structures. Using phonon and electron interaction kinetics and self-consistent ensemble Monte Carlo, we find the favorable conditions for unassisted absorption of hot phonons and design graded heterobarriers for their direct conversion into electric energy. Tandem barriers with nearly optical-phonon height allow for substantial potential gain without current loss. We find that 19% of hot phonons can be harvested with an optimized GaAs/AlxGa1-xAs barrier structure over a range of current and electron densities, thus enhancing the overall energy conversion efficiency and reducing waste heat.

  16. Numerical analysis of wave generation and propagation in a focused surface acoustic wave device for potential microfluidics applications.

    PubMed

    Sankaranarayanan, Subramanian K R S; Bhethanabotla, Venkat R

    2009-03-01

    We develop a 3-D finite element model of a focused surface acoustic wave (F-SAW) device based on LiNbO(3) to analyze the wave generation and propagation characteristics for devices operating at MHz frequencies with varying applied input voltages. We compare the F-SAW device to a conventional SAW device with similar substrate dimensions and transducer finger periodicity. SAW devices with concentrically shaped focused interdigital transducer fingers (F-IDTs) are found to excite waves with high intensity and high beam-width compression ratio, confined to a small localized area. F-SAW devices are more sensitive to amplitude variations at regions close to the focal point than conventional SAW devices having uniform IDT configuration. We compute F-SAW induced streaming forces and velocity fields by applying a successive approximation technique to the Navier-Stokes equation (Nyborg's theory). The maximum streaming force obtained at the focal point varies as the square of the applied input voltage. Computed streaming velocities at the focal point in F-SAW devices are at least an order of magnitude higher than those in conventional SAW devices. Simulated frequency response indicates higher insertion losses in F-SAW devices than in conventional devices, reflecting their greater utility as actuators than as sensors. Our simulation findings suggest that F-SAW devices can be utilized effectively for actuation in microfluidic applications involving diffusion limited transport processes. PMID:19411221

  17. 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.

  18. Three-dimensional Ultrathin Planar Lenses by Acoustic Metamaterials

    PubMed Central

    Li, Yong; Yu, Gaokun; Liang, Bin; Zou, Xinye; Li, Guangyun; Cheng, Su; Cheng, Jianchun

    2014-01-01

    Acoustic lenses find applications in various areas ranging from ultrasound imaging to nondestructive testing. A compact-size and high-efficient planar acoustic lens is crucial to achieving miniaturization and integration, and should have deep implication for the acoustic field. However its realization remains challenging due to the trade-off between high refractive-index and impedance-mismatch. Here we have designed and experimentally realized the first ultrathin planar acoustic lens capable of steering the convergence of acoustic waves in three-dimensional space. A theoretical approach is developed to analytically describe the proposed metamaterial with hybrid labyrinthine units, which reveals the mechanism of coexistence of high refractive index and well-matched impedance. A hyperbolic gradient-index lens design is fabricated and characterized, which can enhance the acoustic energy by 15 dB at the focal point with very high transmission efficiency. Remarkably, the thickness of the lens is only approximately 1/6 of the operating wavelength. The lens can work within a certain frequency band for which the ratio between the bandwidth and the center frequency reaches 0.74. By tailoring the structure of the metamaterials, one can further reduce the thickness of the lens or even realize other acoustic functionalities, opening new opportunity for manipulation of low-frequency sounds with versatile potential. PMID:25354997

  19. Three-dimensional Ultrathin Planar Lenses by Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Li, Yong; Yu, Gaokun; Liang, Bin; Zou, Xinye; Li, Guangyun; Cheng, Su; Cheng, Jianchun

    2014-10-01

    Acoustic lenses find applications in various areas ranging from ultrasound imaging to nondestructive testing. A compact-size and high-efficient planar acoustic lens is crucial to achieving miniaturization and integration, and should have deep implication for the acoustic field. However its realization remains challenging due to the trade-off between high refractive-index and impedance-mismatch. Here we have designed and experimentally realized the first ultrathin planar acoustic lens capable of steering the convergence of acoustic waves in three-dimensional space. A theoretical approach is developed to analytically describe the proposed metamaterial with hybrid labyrinthine units, which reveals the mechanism of coexistence of high refractive index and well-matched impedance. A hyperbolic gradient-index lens design is fabricated and characterized, which can enhance the acoustic energy by 15 dB at the focal point with very high transmission efficiency. Remarkably, the thickness of the lens is only approximately 1/6 of the operating wavelength. The lens can work within a certain frequency band for which the ratio between the bandwidth and the center frequency reaches 0.74. By tailoring the structure of the metamaterials, one can further reduce the thickness of the lens or even realize other acoustic functionalities, opening new opportunity for manipulation of low-frequency sounds with versatile potential.

  20. Technical Potential of Solar Energy to Address Energy Poverty and Avoid GHG Emissions in Africa

    SciTech Connect

    Cowlin, S. C.; Heimiller, D.; Bilello, D.; Renne, D.

    2008-01-01

    This analysis explores the technical potential of photovoltaics (PV) or concentrating solar power (CSP) to address energy poverty in Africa through a geographic information system (GIS) screening of solar resource data developed by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL).

  1. U.S. Building-Sector Energy Efficiency Potential

    SciTech Connect

    Brown, Rich; Borgeson, Sam; Koomey, Jon; Biermayer, Peter

    2008-09-30

    This paper presents an estimate of the potential for energy efficiency improvements in the U.S. building sector by 2030. The analysis uses the Energy Information Administration's AEO 2007 Reference Case as a business-as-usual (BAU) scenario, and applies percentage savings estimates by end use drawn from several prior efficiency potential studies. These prior studies include the U.S. Department of Energy's Scenarios for a Clean Energy Future (CEF) study and a recent study of natural gas savings potential in New York state. For a few end uses for which savings estimates are not readily available, the LBNL study team compiled technical data to estimate savings percentages and costs of conserved energy. The analysis shows that for electricity use in buildings, approximately one-third of the BAU consumption can be saved at a cost of conserved energy of 2.7 cents/kWh (all values in 2007 dollars), while for natural gas approximately the same percentage savings is possible at a cost of between 2.5 and 6.9 $/million Btu. This cost-effective level of savings results in national annual energy bill savings in 2030 of nearly $170 billion. To achieve these savings, the cumulative capital investment needed between 2010 and 2030 is about $440 billion, which translates to a 2-1/2 year simple payback period, or savings over the life of the measures that are nearly 3.5 times larger than the investment required (i.e., a benefit-cost ratio of 3.5).

  2. 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.

  3. An exploration of the ozone dimer potential energy surface

    SciTech Connect

    Azofra, Luis Miguel; Alkorta, Ibon; Scheiner, Steve

    2014-06-28

    The (O{sub 3}){sub 2} dimer potential energy surface is thoroughly explored at the ab initio CCSD(T) computational level. Five minima are characterized with binding energies between 0.35 and 2.24 kcal/mol. The most stable may be characterized as slipped parallel, with the two O{sub 3} monomers situated in parallel planes. Partitioning of the interaction energy points to dispersion and exchange as the prime contributors to the stability, with varying contributions from electrostatic energy, which is repulsive in one case. Atoms in Molecules analysis of the wavefunction presents specific O⋯O bonding interactions, whose number is related to the overall stability of each dimer. All internal vibrational frequencies are shifted to the red by dimerization, particularly the antisymmetric stretching mode whose shift is as high as 111 cm{sup −1}. In addition to the five minima, 11 higher-order stationary points are identified.

  4. An exploration of the ozone dimer potential energy surface

    NASA Astrophysics Data System (ADS)

    Azofra, Luis Miguel; Alkorta, Ibon; Scheiner, Steve

    2014-06-01

    The (O3)2 dimer potential energy surface is thoroughly explored at the ab initio CCSD(T) computational level. Five minima are characterized with binding energies between 0.35 and 2.24 kcal/mol. The most stable may be characterized as slipped parallel, with the two O3 monomers situated in parallel planes. Partitioning of the interaction energy points to dispersion and exchange as the prime contributors to the stability, with varying contributions from electrostatic energy, which is repulsive in one case. Atoms in Molecules analysis of the wavefunction presents specific O⋯O bonding interactions, whose number is related to the overall stability of each dimer. All internal vibrational frequencies are shifted to the red by dimerization, particularly the antisymmetric stretching mode whose shift is as high as 111 cm-1. In addition to the five minima, 11 higher-order stationary points are identified.

  5. An exploration of the ozone dimer potential energy surface.

    PubMed

    Azofra, Luis Miguel; Alkorta, Ibon; Scheiner, Steve

    2014-06-28

    The (O3)2 dimer potential energy surface is thoroughly explored at the ab initio CCSD(T) computational level. Five minima are characterized with binding energies between 0.35 and 2.24 kcal/mol. The most stable may be characterized as slipped parallel, with the two O3 monomers situated in parallel planes. Partitioning of the interaction energy points to dispersion and exchange as the prime contributors to the stability, with varying contributions from electrostatic energy, which is repulsive in one case. Atoms in Molecules analysis of the wavefunction presents specific O⋯O bonding interactions, whose number is related to the overall stability of each dimer. All internal vibrational frequencies are shifted to the red by dimerization, particularly the antisymmetric stretching mode whose shift is as high as 111 cm(-1). In addition to the five minima, 11 higher-order stationary points are identified. PMID:24985642

  6. 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.

  7. 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.

  8. Measurement of complex acoustic intensity in an acoustic waveguide.

    PubMed

    Duan, Wenbo; Kirby, Ray; Prisutova, Jevgenija; Horoshenkov, Kirill V

    2013-11-01

    Acoustic intensity is normally treated as a real quantity, but in recent years, many articles have appeared in which intensity is treated as a complex quantity where the real (active) part is related to local mean energy flow and the imaginary (reactive) part to local oscillatory transport of energy. This offers the potential to recover additional information about a sound field and then to relate this to the properties of the sound source and the environment that surrounds it. However, this approach is applicable only to multi-modal sound fields, which places significant demands on the accuracy of the intensity measurements. Accordingly, this article investigates the accuracy of complex intensity measurements obtained using a tri-axial Microflown intensity probe by comparing measurement and prediction for sound propagation in an open flanged pipe. Under plane wave conditions, comparison between prediction and experiment reveals good agreement, but when a higher order mode is present, the reactive intensity field becomes complicated and agreement is less successful. It is concluded that the potential application of complex intensity as a diagnostic tool is limited by difficulties in measuring reactive intensity in complex sound fields when using current state of the art acoustic instrumentation. PMID:24180778

  9. 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

  10. Acoustic properties of triggered lightning

    NASA Astrophysics Data System (ADS)

    Dayeh, M. A.; Evans, N.; Ramaekers, J.; Trevino, J.; Rassoul, H.; Lucia, R. J.; Dwyer, J. R.; Uman, M. A.; Jordan, D. M.

    2014-12-01

    Acoustic signatures from rocket-triggered lightning are measured by a 15m long, one-dimensional microphone array consisting of 16 receivers situated 90 meters from the lightning channel. Measurements were taken at the International Center for Lightning Research and Testing (ICLRT) in Camp Blanding, FL during the summer of 2014. The linear array was oriented in an end-fire position so that the peak acoustic reception pattern can be steered vertically along the channel with a frequency-dependent spatial resolution, enabling us to sample the acoustic signatures from different portions along the lightning channel. We report on the characteristics of acoustic signatures associated with several return strokes in 6 measured flashes (total of 29 return strokes). In addition, we study the relationship between the amplitude, peak frequency, and inferred energy input of each stroke acoustic signature and the associated measured lightning parameters. Furthermore, challenges of obtaining acoustic measurements in thunderstorm harsh conditions and their countermeasures will also be discussed.

  11. Individual variation in the echolocation calls of big brown bats (Eptesicus fuscus) and their potential for acoustic identification and censusing

    NASA Astrophysics Data System (ADS)

    Burnett, Stephen Cameron

    We compared the discriminability of the echolocation calls of big brown bats (Eptesicus fuscus) in three situations: (a)while held in the hand, (b)while perched on a platform, and (c)while flying in an anechoic chamber. Using variables describing each sonar call, we employed discriminant function analysis (DFA) to assign calls to bat across recording situations (which yielded 72% success), and, within a given recording situation (87% success). Advances in computer equipment made it possible to replace our laboratory recording equipment with a laptop- based system. Using widely available software tools, it is also possible to take recordings analyze them automatically on a computer. This allows a researcher to record and analyze large numbers of calls without investing unreasonable amounts of time. We recorded sonar calls of bats under laboratory and field conditions and tested the ability of neural networks to estimate the number of bats that produced a given set of recordings. Laboratory tests used calls from both big brown bats (E. fuscus) and little brown bats ( Myotis lucifugus) while field tests used calls from E. fuscus only. The number of animals tested in the lab ranged from three to 24 and in all cases the estimate was within 11 of the correct number. For field recordings, we tested between three and 26 animals and all estimates were within four of the correct number of bats. These results suggest that neural networks might be useful for acoustic censusing of bats in the field. We tested a series of laboratory recordings of the sonar calls of E. fuscus with DFA and backpropagation neural networks to discriminate sonar calls using recordings made after various intervals. DFA could distinguish animals from recordings made up to five years apart; however, the network was unable to discriminate animals over time spans as short as five months. Using a distance measurement calculated during DFA, we found that bats recorded within five months could be

  12. Residential energy efficiency: Progress since 1973 and future potential

    NASA Astrophysics Data System (ADS)

    Rosenfeld, Arthur H.

    1985-11-01

    Today's 85 million U.S. homes use 100 billion of fuel and electricity (1150/home). If their energy intensity (resource energy/ft2) were still frozen at 1973 levels, they would use 18% more. With well-insulated houses, need for space heat is vanishing. Superinsulated Saskatchewan homes spend annually only 270 for space heat, 150 for water heat, and 400 for appliances, yet they cost only 2000±1000 more than conventional new homes. The concept of Cost of Conserved Energy (CCE) is used to rank conservation technologies for existing and new homes and appliances, and to develop supply curves of conserved energy and a least cost scenario. Calculations are calibrated with the BECA and other data bases. By limiting investments in efficiency to those whose CCE is less than current fuel and electricity prices, the potential residential plus commercial energy use in 2000 AD drops to half of that estimated by DOE, and the number of power plants needed drops by 200. For the whole buildings sector, potential savings by 2000 are 8 Mbod (worth 50B/year), at an average CCE of 10/barrel.

  13. Potential for luminosity improvement for low-energy RHIC operation

    SciTech Connect

    Fedotov A. V.

    2012-05-20

    At the Brookhaven National Laboratory, a physics program, motivated by the search of the QCD phase transition critical point, requires operation of the Relativistic Heavy Ion Collider (RHIC) with heavy ions at very low beam energies corresponding to 2.5-20 GeV/n. Several physics runs were already successfully performed at these low energies. However, the luminosity is very low at lowest energies of interest (< 10 GeV/n) limited by the intra-beam scattering and space-charge, as well as by machine nonlinearities. At these low energies, electron cooling could be very effective in counteracting luminosity degradation due to the IBS, while it is less effective against other limitations. Overall potential luminosity improvement for low-energy RHIC operation from cooling is summarized for various energies, taking into account all these limitations as well as beam lifetime measured during the low-energy RHIC runs. We also explore a possibility of further luminosity improvement under the space-charge limitation.

  14. Evaluation of global onshore wind energy potential and generation costs.

    PubMed

    Zhou, Yuyu; Luckow, Patrick; Smith, Steven J; Clarke, Leon

    2012-07-17

    In this study, we develop an updated global estimate of onshore wind energy potential using reanalysis wind speed data, along with updated wind turbine technology performance, land suitability factors, cost assumptions, and explicit consideration of transmission distance in the calculation of transmission costs. We find that wind has the potential to supply a significant portion of the world energy needs, although this potential varies substantially by region and with assumptions such as on what types of land can be used to site wind farms. Total global economic wind potential under central assumptions, that is, intermediate between optimistic and pessimistic, is estimated to be approximately 119.5 petawatt hours per year (13.6 TW) at less than 9 cents/kWh. A sensitivity analysis of eight key parameters is presented. Wind potential is sensitive to a number of input parameters, particularly wind speed (varying by -70% to +450% at less than 9 cents/kWh), land suitability (by -55% to +25%), turbine density (by -60% to +80%), and cost and financing options (by -20% to +200%), many of which have important policy implications. As a result of sensitivities studied here we suggest that further research intended to inform wind supply curve development focus not purely on physical science, such as better resolved wind maps, but also on these less well-defined factors, such as land-suitability, that will also have an impact on the long-term role of wind power. PMID:22715929

  15. Exact energy spectrum for models with equally spaced point potentials

    NASA Astrophysics Data System (ADS)

    Caudrelier, V.; Crampé, N.

    2006-03-01

    We describe a non-perturbative method for computing the energy band structures of one-dimensional models with general point potentials sitting at equally spaced sites. This is done thanks to a Bethe ansatz approach and the method is applicable even when periodicity is broken, that is when Bloch's theorem is not valid any more. We derive the general equation governing the energy spectrum and illustrate its use in various situations. In particular, we get exact results for boundary effects. We also study non-perturbatively the effects of impurities in such systems. Finally, we discuss the possibility of including interactions between the particles of these systems.

  16. Bifurcations on Potential Energy Surfaces of Organic Reactions

    PubMed Central

    Ess, Daniel H.; Wheeler, Steven E.; Iafe, Robert G.; Xu, Lai; Çelebi-Ölçüm, Nihan; Houk, K. N.

    2009-01-01

    A single transition state may lead to multiple intermediates or products if there is a post-transition state reaction path bifurcation. These bifurcations arise when there are sequential transition states with no intervening energy minimum. For such systems, the shape of the potential energy surface and dynamic effects control selectivity rather than transition state energetics. This minireview covers recent investigations of organic reactions exhibiting reaction pathway bifurcations. Such phenomena are surprisingly general and affect experimental observables such as kinetic isotope effects and product distributions. PMID:18767086

  17. Quintom dark energy models with nearly flat potentials

    SciTech Connect

    Setare, M. R.; Saridakis, E. N.

    2009-02-15

    We examine quintom dark energy models, produced by the combined consideration of a canonical and a phantom field, with nearly flat potentials and dark energy equation-of-state parameter w{sub DE} close to -1. We find that all such models converge to a single expression for w{sub DE}(z), depending only on the initial field values and their derivatives. We show that this quintom paradigm allows for a description of the transition through -1 in the near cosmological past. In addition, we provide the necessary conditions for the determination of the direction of the -1 crossing.

  18. A global potential energy surface for ArH2

    NASA Technical Reports Server (NTRS)

    Schwenke, David W.; Walch, Stephen P.; Taylor, Peter R.

    1992-01-01

    We describe a simple analytic representation of the ArH2 potential energy surface which well reproduces the results of extensive ab initio electronic structure calculations. The analytic representation smoothly interpolates between the dissociated H2 and strong bonding limits. In the fitting process, emphasis is made on accurately reproducing regions of the potential expected to be important for high temperature (ca. 3000 K) collision processes. Overall, the anisotropy and H2 bond length dependence of the analytic representation well reproduce the input data.

  19. Mean Flow Augmented Acoustics in Rocket Systems

    NASA Technical Reports Server (NTRS)

    Fischbach, Sean

    2014-01-01

    Combustion instability in solid rocket motors and liquid engines has long been a subject of concern. Many rockets display violent fluctuations in pressure, velocity, and temperature originating from the complex interactions between the combustion process and gas dynamics. Recent advances in energy based modeling of combustion instabilities require accurate determination of acoustic frequencies and mode shapes. Of particular interest is the acoustic mean flow interactions within the converging section of a rocket nozzle, where gradients of pressure, density, and velocity become large. The expulsion of unsteady energy through the nozzle of a rocket is identified as the predominate source of acoustic damping for most rocket systems. Recently, an approach to address nozzle damping with mean flow effects was implemented by French [1]. This new approach extends the work originated by Sigman and Zinn [2] by solving the acoustic velocity potential equation (AVPE) formulated by perturbing the Euler equations [3]. The present study aims to implement the French model within the COMSOL Multiphysiscs framework and analyzes one of the author's presented test cases.

  20. The Potential For Energy Efficiency In The State of Iowa

    SciTech Connect

    Hadley, SW

    2001-12-05

    The purpose of this study was to do an initial estimate of the potential for energy savings in the state of Iowa. Several methods for determining savings were examined, including existing programs, surveys, savings calculators, and economic simulation. Each method has advantages and disadvantages, trading off between detail of information, accuracy of results, and scope. This paper concentrated on using economic simulation (the NEMS model (EIA 2000a)) to determine market potential for energy savings for the residential and commercial sectors. The results of surveys were used to calculate the economic potential for savings in the industrial sector. The NEMS model is used by the Energy Information Administration to calculate twenty-year projections of energy use for every region of the country. The results of the Annual Energy Outlook 2000 were used as the Base case (EIA 1999a). Two alternative cases were created to simulate energy savings policies. Voluntary, market-related programs were simulated by lowering the effective discount rates that end-users use when making decisions on equipment purchases. Standards programs in the residential sector were simulated by eliminating the availability of low efficiency equipment in future years. The parameters for these programs were based on the Moderate scenario from the DOE Clean Energy Futures study (Interlaboratory Working Group 2000), which assumed increased concern by society on energy efficiency but not to the point of fiscal policies such as taxes or direct subsidies. The study only considered a subset of the various programs, policies, and technologies that could reduce energy use. The major end-uses in the residential sector affected by the policies were space cooling (20% savings by 2020) and water heating (14% savings by 2020.) Figure S-1 shows the space cooling savings when voluntary programs and minimum efficiency standards were implemented. Refrigerators, freezers, and clothes dryers saw slight improvements

  1. Computed rotational rainbows from realistic potential energy surfaces

    SciTech Connect

    Gianturco, F.A.; Palma, A.

    1985-08-01

    The quantal IOS approximation in here employed to study interference structures in the rotationally inelastic, state-to-state differential cross sections for polar diatomic targets (LiH, FH, and CO) interacting with He atoms. Quite realistic expressions are used to describe the relevant potential energy surfaces (PES) which were taken from previous works that tested them against accurate experimental findings for total and partial differential cross sections. Specific features like short-range anisotropy and well depth, long-range attractive regions and overall range of action for each potential employed are analyzed and discussed in relation to their influence on rotational rainbows appearance and on the possible observation of cross section extrema in rotational energy distributions.

  2. Geothermal Energy Potential of Turkey: Inferred from the Aeromagnetic data

    NASA Astrophysics Data System (ADS)

    Ates, Abdullah; Bilim, Funda; Buyuksarac, Aydin; Bektas, Ozcan

    2010-05-01

    Geothermal energy potential of Turkey is well known. There are lots of hot springs with over 30° C water temperatures. However, the significance of these geothermal energy potential of Turkey is not adequately understood. We believe that the main reason for this; is the lack of exploration methods and tools in a wide area as large as Turkey. We exploited a well known physical property of rocks to estimate the geothermal energy potential. Physically, substances lose their magnetization above a temperature known as the Curie that is the 580° C for magnetite. Properties of the Curie temperature have been exploited to observe the bottom depth of the magnetization. That is the depth where the heat reaches to 580° C. In another word, there is no magnetization below this depth. In normal crust this depth is about 22-24 km. Thus, investigation of the bottom depth of magnetization by using aeromagnetic anomalies can lead to information that if there are any anomalous regions well above the normal crust. The aeromagnetic anomalies of whole of Turkey were surveyed by the Mineral Research and Exploration (MTA) of Turkey. The survey was completed during late 1980's. Five kilometers grid data were available and used for regional exploration purposes. Exploration of the geothermal energy potential of Turkey was done from west to east in the similar way to search for shallow high temperature regions. These are from west to east; i.) Western Turkey: Two major shallow depth regions were determined at the west of Kutahya and the north-east of Denizli. The Curie Point Depths (CPDs) were calculated as about 7 km and about 9 km in Kutahya and Denizli, respectively. Also, high heat flow values and crustal thinning (about 32 km from gravity anomalies of western Turkey) were calculated for western Turkey. ii.) Central Turkey: A CPD depth of 8 km was calculated. This gives us a temperature gradient of 0.073° C/m. Geothermal energy potential was studied using water chemistry and isotopic

  3. The potential impact of hydrogen energy use on the atmosphere

    NASA Astrophysics Data System (ADS)

    van Ruijven, B. J.; Lamarque, J. F.; van Vuuren, D. P.; Kram, T.; Eerens, H.

    2009-04-01

    Energy models show very different trajectories for future energy systems (partly as function of future climate policy). One possible option is a transition towards a hydrogen-based energy system. The potential impact of such hydrogen economy on atmospheric emissions is highly uncertain. On the one hand, application of hydrogen in clean fuel cells reduces emissions of local air pollutants, like SOx and NOx. On the other hand, emissions of hydrogen from system leakages are expected to change the atmospheric concentrations and behaviour (see also Price et al., 2007; Sanderson et al., 2003; Schultz et al., 2003; Tromp et al., 2003). The uncertainty arises from several sources: the expected use of hydrogen, the intensity of leakages and emissions, and the atmospheric chemical behaviour of hydrogen. Existing studies to the potential impacts of a hydrogen economy on the atmosphere mostly use hydrogen emission scenarios that are based on simple assumptions. This research combines two different modelling efforts to explore the range of impacts of hydrogen on atmospheric chemistry. First, the potential role of hydrogen in the global energy system and the related emissions of hydrogen and other air pollutants are derived from the global energy system simulation model TIMER (van Vuuren, 2007). A set of dedicated scenarios on hydrogen technology development explores the most pessimistic and optimistic cases for hydrogen deployment (van Ruijven et al., 2008; van Ruijven et al., 2007). These scenarios are combined with different assumptions on hydrogen emission factors. Second, the emissions from the TIMER model are linked to the NCAR atmospheric model (Lamarque et al., 2005; Lamarque et al., 2008), in order to determine the impacts on atmospheric chemistry. By combining an energy system model and an atmospheric model, we are able to consistently explore the boundaries of both hydrogen use, emissions and impacts on atmospheric chemistry. References: Lamarque, J.-F., Kiehl, J. T

  4. Classroom Acoustics: Understanding Barriers to Learning.

    ERIC Educational Resources Information Center

    Crandell, Carl C., Ed.; Smaldino, Joseph J., Ed.

    2001-01-01

    This booklet explores classroom acoustics and their importance on the learning potential of children with hearing loss and related disabilities. The booklet also reviews research on classroom acoustics and the need for the development of classroom acoustics standards. Chapters examine: 1) a speech-perception model demonstrating the linkage between…

  5. Acoustically swept rotor. [helicopter noise reduction

    NASA Technical Reports Server (NTRS)

    Schmitz, F. H.; Boxwell, D. A.; Vause, R. (Inventor)

    1979-01-01

    Impulsive noise reduction is provided in a rotor blade by acoustically sweeping the chord line from root to tip so that the acoustic radiation resulting from the summation of potential singularities used to model the flow about the blade tend to cancel for all times at an observation point in the acoustic far field.

  6. Theoretical characterization of the potential energy surface for NH + NO

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1993-01-01

    The potential energy surface for NH + NO was characterized using complete active space self-consistent field (CASSCF) gradient calculation to determine the stationary point geometries and frequencies followed by CASSCF/internally contracted configuration interaction calculations to refine the energetics. The present results are in qualitative accord with the BAC-MP4 calculations, but there are differences as large as 8 kcal/mol in the detailed energetics.

  7. Electronic structure, molecular bonding and potential energy surfaces

    SciTech Connect

    Ruedenberg, K.

    1993-12-01

    By virtue of the universal validity of the generalized Born-Oppenheimer separation, potential energy surfaces (PES`) represent the central conceptual as well as quantitative entities of chemical physics and provide the basis for the understanding of most physicochemical phenomena in many diverse fields. The research in this group deals with the elucidation of general properties of PES` as well as with the quantitative determination of PES` for concrete systems, in particular pertaining to reactions involving carbon, oxygen, nitrogen and hydrogen molecules.

  8. MCSCF potential energy surface for photodissociation of formaldehyde

    NASA Technical Reports Server (NTRS)

    Jaffe, R. L.; Morokuma, K.

    1976-01-01

    The ground state potential energy surface for the dissociation of formaldehyde (H2CO to H2 and CO) is calculated with the ab initio MCSCF method with an extended (4-31G) basis set. The location, barrier height, and force constants of the transition state are determined, and the normal coordinate analysis is carried out. The calculated barrier height is 4.5 eV. Based on the calculated quantities, the detailed mechanism of the photochemical dissociation is discussed.

  9. Electromagnetic potentials basis for energy density and power flux

    NASA Astrophysics Data System (ADS)

    Puthoff, H. E.

    2016-09-01

    In rounding out the education of students in advanced courses in applied electromagnetics it is incumbent on us as mentors to raise issues that encourage appreciation of certain subtle aspects that are often overlooked during first exposure to the field. One of these has to do with the interplay between fields and potentials, with the latter often seen as just a convenient mathematical artifice useful in solving Maxwell’s equations. Nonetheless, to those practiced in application it is well understood that various alternatives in the use of fields and potentials are available within electromagnetic (EM) theory for the definitions of energy density, momentum transfer, EM stress–energy tensor, and so forth. Although the various options are all compatible with the basic equations of electrodynamics (e.g., Maxwell’s equations, Lorentz force law, gauge invariance), nonetheless certain alternative formulations lend themselves to being seen as preferable to others with regard to the transparency of their application to physical problems of interest. Here we argue for the transparency of an energy density/power flux option based on the EM potentials alone.

  10. Molecular potential energy surfaces for interstellar chemistry and fusion applications

    NASA Astrophysics Data System (ADS)

    Braams, Bastiaan J.; Huang, Xinchuan; Jin, Zhong; Xie, Zhen; Zhang, Xiubin; Bowman, Joel M.; Sharma, Amit Raj; Scheider, Ralf

    2006-04-01

    In the Born-Oppenheimer approximation the electronic Schr"odinger equation is solved given the nuclear positions as parameters, and this defines the potential energy surface. We have used computational invariant theory and the MAGMA computer algebra system as an aid to develop representations for the potential energy and dipole moment surfaces that are fully invariant under permutations of like nuclei, extending an approach that for 3-body and 4-body systems has a long history, e.g. [J. N. Murrell et al. Molecular Potential Energy Functions, Wiley, 1984]. A many-body (cluster) expansion is used to describe reaction complexes. The methods have been applied in an almost routine way for systems of up to 7 nuclei, including several molecules that are of interest for interstellar chemistry and for the issue of hydrocarbon breakdown in fusion edge plasma: H5^+, CH5, CH5^+, C2H3^+, and their fragments, with C2H5^+ on the way. The mathematical and computional methods and the hydrocarbon applications will be presented.

  11. Assessment of Tidal Stream Energy Potential for the United States

    NASA Astrophysics Data System (ADS)

    Haas, K. A.; Defne, Z.; Jiang, L.; Fritz, H. M.

    2010-12-01

    Tidal streams are high velocity sea currents created by periodic horizontal movement of the tides, often magnified by local topographical features such as headlands, inlets to inland lagoons, and straits. Tidal stream energy extraction is derived from the kinetic energy of the moving flow; analogous to the way a wind turbine operates in air, and as such differs from tidal barrages, which relies on providing a head of water for energy extraction. With the constantly increasing effort in promoting alternative energy, tidal streams have become promising energy sources due to their continuous, predictable and concentrated characteristics. However, the present lack of a full spatial-temporal assessment of tidal currents for the U.S. coastline down to the scale of individual devices is a barrier to the comprehensive development of tidal current energy technology. A methodology for creating a national database of tidal stream energy potential, as well as a GIS tool usable by industry in order to accelerate the market for tidal energy conversion technology has been developed. The tidal flows are simulated using the Regional Ocean Modeling System (ROMS). The model is calibrated and validated using observations and tidal predictions. The calibration includes adjustments to model parameters such as bottom friction coefficient, changed land/water masks, or increased grid resolutions. A systematic validation process has been developed after defining various parameters to quantify the validation results. In order to determine the total tidal stream power resource, a common method frequently proposed is to estimate it as a fraction of the total kinetic energy flux passing through a vertical section; however, this now has been shown to generally underestimate the total available resource. The total tidal energy flux includes not just the kinetic energy but also the energy flux due to the work done by the pressure force associated with the tidal motion on the water column as well

  12. Mashreq Arab interconnected power system potential for economic energy trading

    SciTech Connect

    Al-Shehri, A.M.; El-Amin, I.M.; Opoku, G.; Al-Baiyat, S.A.; Zedan, F.M.

    1994-12-01

    The Mashreq Arab countries covered in this study are Bahrain, Egypt, Jordan, Lebanon, Oman, Qatar, Saudi Arabia, Syria, the United Arab Emirates, and Yemen. A feasibility study for the interconnection of the electrical networks of the Mashreq Arab countries, sponsored by the Arab Fund, was completed in June 1992. Each country is served by one utility except Saudi Arabia, which is served by four major utilities and some smaller utilities serving remote towns and small load centers. The major utilities are the Saudi consolidated electric Company in the Eastern Province (SCECO East), SCECO Center, SCECO West, and SCECO South. These are the ones considered in this study. The Mashreq Arab region has a considerable mix of energy resources. Egypt and Syria have some limited amounts of hydropower resources, and the Arabian Gulf region is abundant in fossil fuel reserves. Owing to the differences in energy production costs, a potential exists for substantial energy trading between electric utilities in the region. The major objective of this project is to study the feasibility of electric energy trading between the Mashreq Arab countries. The basis, assumptions, and methodologies on which this energy trading study is based relate to the results and conclusions arising out of the previous study, power plant characteristics and costs, assumptions on economic parameters, rules for economy energy exchange, etc. This paper presents the basis, methodology, and major findings of the study.

  13. Data Network Equipment Energy Use and Savings Potential in Buildings

    SciTech Connect

    Lanzisera, Steven; Nordman, Bruce; Brown, Richard E.

    2010-06-09

    Network connectivity has become nearly ubiquitous, and the energy use of the equipment required for this connectivity is growing. Network equipment consists of devices that primarily switch and route Internet Protocol (IP) packets from a source to a destination, and this category specifically excludes edge devices like PCs, servers and other sources and sinks of IP traffic. This paper presents the results of a study of network equipment energy use and includes case studies of networks in a campus, a medium commercial building, and a typical home. The total energy use of network equipment is the product of the stock of equipment in use, the power of each device, and their usage patterns. This information was gathered from market research reports, broadband market penetration studies, field metering, and interviews with network administrators and service providers. We estimate that network equipment in the USA used 18 TWh, or about 1percent of building electricity, in 2008 and that consumption is expected to grow at roughly 6percent per year to 23 TWh in 2012; world usage in 2008 was 51 TWh. This study shows that office building network switches and residential equipment are the two largest categories of energy use consuming 40percent and 30percent of the total respectively. We estimate potential energy savings for different scenarios using forecasts of equipment stock and energy use, and savings estimates range from 20percent to 50percent based on full market penetration of efficient technologies.

  14. Acoustical Characterization of the Columbia River Estuary

    NASA Astrophysics Data System (ADS)

    Reeder, D. B.

    2014-12-01

    Investigations of near-shore and in-shore environments have, rightly, focused on geological, thermodynamic and hydrodynamic parameters. A complementary acoustical characterization of the estuarine environment provides another layer of information to facilitate a more complete understanding of the physical environment. Relatively few acoustical studies have been carried out in rivers, estuaries or other energetic environments; nearly all acoustical work in such environments has been done at high acoustic frequencies—in the 10's and 100's of kHz. To this end, within the context of a larger hydrodynamic field experiment (RIVET II), a small acoustic field experiment was carried out in the Columbia River Estuary (CRE), the acoustic objective of which was to characterize the acoustic environment in the CRE in terms of ambient noise field statistics and acoustic propagation characteristics at low-to-mid-frequencies. Acoustically, the CRE salt wedge consists of two isospeed layers separated by a thin, three-dimensional high-gradient layer. Results demonstrate that (1) this stratification supports ducting of low-angle acoustic energy in the upper layer and the creation of an acoustic shadow zone in the lower layer; (2) the spatiotemporal dynamics of the salt wedge structure during the very energetic flood and ebb tides induce significant variability in the acoustic environment, as well as significant flow noise across the acoustic transducer; and (3) this flow noise correlates to current velocity and complicates acoustical observations at low frequencies.

  15. Market potential for optical fiber sensors in the energy sector

    NASA Astrophysics Data System (ADS)

    Bosselmann, T.

    2007-07-01

    For a long time electric power was taken as a natural unlimited resource. With globalisation the demand for energy has risen. This has brought rising prices for fossil fuels, as well as a diversification of power generation. Besides conventional fossil, nuclear plants are coming up again. Renewable energy sources are gaining importance resulting in recent boom of wind energy plants. In the past reliability and availability and an extremely long lifetime were of paramount importance. Today this has been added by cost, due to the global competition and the high fuel costs. New designs of power components have increased efficiency using lesser material. Higher efficiency causes inevitably higher stress on the materials, of which the machines are built. As a reduction of lifetime is not acceptable and maintenance costs are expected to be at a minimum, condition monitoring systems are going to being used now. This offers potentials for fibre optic sensor application.

  16. The Potential of Renewable Energy Sources in Latvia

    NASA Astrophysics Data System (ADS)

    Sakipova, S.; Jakovics, A.; Gendelis, S.

    2016-02-01

    The article discusses some aspects of the use of renewable energy sources in the climatic conditions prevailing in most of the territory of Latvia, with relatively low wind speeds and a small number of sunny days a year. The paper gives a brief description of the measurement equipment and technology to determine the parameters of the outer air; the results of the measurements are also analysed. On the basis of the data obtained during the last two years at the meteorological station at the Botanical Garden of the University of Latvia, the energy potential of solar radiation and wind was estimated. The values of the possible and the actual amount of produced energy were determined.

  17. Potential energy surface of triplet N2O2

    NASA Astrophysics Data System (ADS)

    Varga, Zoltan; Meana-Pañeda, Rubén; Song, Guoliang; Paukku, Yuliya; Truhlar, Donald G.

    2016-01-01

    We present a global ground-state triplet potential energy surface for the N2O2 system that is suitable for treating high-energy vibrational-rotational energy transfer and collision-induced dissociation. The surface is based on multi-state complete-active-space second-order perturbation theory/minimally augmented correlation-consistent polarized valence triple-zeta electronic structure calculations plus dynamically scaled external correlation. In the multireference calculations, the active space has 14 electrons in 12 orbitals. The calculations cover nine arrangements corresponding to dissociative diatom-diatom collisions of N2, O2, and nitric oxide (NO), the interaction of a triatomic molecule (N2O and NO2) with the fourth atom, and the interaction of a diatomic molecule with a single atom (i.e., the triatomic subsystems). The global ground-state potential energy surface was obtained by fitting the many-body interaction to 54 889 electronic structure data points with a fitting function that is a permutationally invariant polynomial in terms of bond-order functions of the six interatomic distances.

  18. Potential energy surface of triplet N2O2.

    PubMed

    Varga, Zoltan; Meana-Pañeda, Rubén; Song, Guoliang; Paukku, Yuliya; Truhlar, Donald G

    2016-01-14

    We present a global ground-state triplet potential energy surface for the N2O2 system that is suitable for treating high-energy vibrational-rotational energy transfer and collision-induced dissociation. The surface is based on multi-state complete-active-space second-order perturbation theory/minimally augmented correlation-consistent polarized valence triple-zeta electronic structure calculations plus dynamically scaled external correlation. In the multireference calculations, the active space has 14 electrons in 12 orbitals. The calculations cover nine arrangements corresponding to dissociative diatom-diatom collisions of N2, O2, and nitric oxide (NO), the interaction of a triatomic molecule (N2O and NO2) with the fourth atom, and the interaction of a diatomic molecule with a single atom (i.e., the triatomic subsystems). The global ground-state potential energy surface was obtained by fitting the many-body interaction to 54 889 electronic structure data points with a fitting function that is a permutationally invariant polynomial in terms of bond-order functions of the six interatomic distances. PMID:26772574

  19. Acoustic emission linear pulse holography

    DOEpatents

    Collins, H.D.; Busse, L.J.; Lemon, D.K.

    1983-10-25

    This device relates to the concept of and means for performing Acoustic Emission Linear Pulse Holography, which combines the advantages of linear holographic imaging and Acoustic Emission into a single non-destructive inspection system. This unique system produces a chronological, linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. The innovation is the concept of utilizing the crack-generated acoustic emission energy to generate a chronological series of images of a growing crack by applying linear, pulse holographic processing to the acoustic emission data. The process is implemented by placing on a structure an array of piezoelectric sensors (typically 16 or 32 of them) near the defect location. A reference sensor is placed between the defect and the array.

  20. 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.

  1. 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 ...

  2. 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.

  3. Measurement of Bubble Size Distribution Based on Acoustic Propagation in Bubbly Medium

    NASA Astrophysics Data System (ADS)

    Wu, Xiongjun; Hsiao, Chao-Tsung; Choi, Jin-Keun; Chahine, Georges

    2013-03-01

    Acoustic properties are strongly affected by bubble size distribution in a bubbly medium. Measurement of the acoustic transmission becomes increasingly difficulty as the void fraction of the bubbly medium increases due to strong attenuation, while acoustic reflection can be measured more easily with increasing void fraction. The ABS ACOUSTIC BUBBLE SPECTROMETER®\\copyright, an instrument for bubble size measurement that is under development tries to take full advantage of the properties of acoustic propagation in bubbly media to extract bubble size distribution. Properties of both acoustic transmission and reflection in the bubbly medium from a range of short single-frequency bursts of acoustic waves at different frequencies are measured in an effort to deduce the bubble size distribution. With the combination of both acoustic transmission and reflection, assisted with validations from photography, the ABS ACOUSTIC BUBBLE SPECTROMETER®\\copyright has the potential to measure bubble size distributions in a wider void fraction range. This work was sponsored by Department of Energy SBIR program

  4. GIS Assessment of Wind Energy Potential in California and Florida

    NASA Astrophysics Data System (ADS)

    Snow, R. K.; Snow, M. M.

    2008-05-01

    Energy efficiency coupled with renewable energy technologies can provide most of the U.S. carbon emissions reductions needed to contain atmospheric carbon concentrations at 450-500 parts per million, considered by many to be a tipping point in mitigating climate change. Among the leaders in the alternative energy sector is wind power, which is now one of the largest sources of new power generation in the U.S. creating jobs and revenue for rural communities while powering our economy with an emissions-free source of energy. In 2006, wind turbines capable of generating more than 2,400 megawatts of electricity were installed in the U.S. and by 2007 this number had risen to 3,000 megawatts. The U.S. generated 31 billion kilowatt-hours of wind power in 2007, which is enough electricity to power the equivalent of nearly 3 million average homes. It is estimated that generating the same amount of electricity would require burning 16 million tons of coal or 50 million barrels of oil. This study examines the wind power potential of sites near populated areas in Florida and California to determine the practicability of installing wind turbines at these locations. A GIS was developed in order to conduct a spatial analysis of these sites based on mean annual wind speed measured in meters per second and wind power density ratings measured in watts per square meter. The analysis indicates that coastal areas of Cocoa Beach, Key West, Hollywood, and West Palm Beach, respectively, possess the greatest potential for wind energy in Florida with mean annual wind speeds of 4.9 m/s and average wind power density ratings of 171 w/m2 peaking at Cocoa Beach followed by wind speeds of 4.64 m/s and wind power ratings of 115 w/m2 at Key West. California wind energy potential is even greater than that of Florida with Fairfield exhibiting mean annual wind speeds of 5.9 m/s and average wind power density ratings of 327 w/m2 followed by the Mojave and Palmdale areas with mean annual wind speeds of

  5. Onshore wind energy potential over Iberia: present and future projections

    NASA Astrophysics Data System (ADS)

    Rochinha, Carlos A.; Santos, João A.; Liberato, Margarida L. R.; Pinto, Joaquim G.

    2014-05-01

    Onshore grid-connected wind power generation has been explored for more than three decades in the Iberian Peninsula. Further, increasing attention has been devoted to renewable energy sources in a climate change context. While advantages of wind energy are widely recognized, its distribution is not spatially homogeneous and not uniform throughout the year. Hence, understanding these spatial-temporal distributions is critical in power system planning. The present study aims at assessing the potential power output estimated from 10 m wind components simulated by a regional climate model (CCLM), driven by ERA40 reanalysis. Datasets are available on a grid with a high spatial resolution (approximately 20 km) and over a 40-yr period (1961-2000). Furthermore, several target sites, located in areas with high installed wind generation capacity, are selected for local-to-regional scale assessments. The results show that potential wind power is higher over northern Iberia, mostly in Cantabria and Galicia, while Andalucía and Cataluña record the lowest values. With respect to the intra-annual variability, summer is by far the season with the lowest potential energy outputs. Furthermore, the inter-annual variability reveals an overall downward long-term trend over the 40-yr period, particularly in the winter time series. A CCLM transient experiment, forced by the SRES A1B emission scenario, is also discussed for a future period (2041-2070), after a model validation/calibration process (bias corrections). Significant changes in the wind power potential are projected for the future throughout Iberia, but their magnitude largely depends on the locations. This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) and by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project STORMEx FCOMP-01-0124-FEDER- 019524 (PTDC/AAC-CLI/121339/2010).

  6. Study of Harmonics-to-Noise Ratio and Critical-Band Energy Spectrum of Speech as Acoustic Indicators of Laryngeal and Voice Pathology

    NASA Astrophysics Data System (ADS)

    Shama, Kumara; krishna, Anantha; Cholayya, Niranjan U.

    2006-12-01

    Acoustic analysis of speech signals is a noninvasive technique that has been proved to be an effective tool for the objective support of vocal and voice disease screening. In the present study acoustic analysis of sustained vowels is considered. A simple[InlineEquation not available: see fulltext.]-means nearest neighbor classifier is designed to test the efficacy of a harmonics-to-noise ratio (HNR) measure and the critical-band energy spectrum of the voiced speech signal as tools for the detection of laryngeal pathologies. It groups the given voice signal sample into pathologic and normal. The voiced speech signal is decomposed into harmonic and noise components using an iterative signal extrapolation algorithm. The HNRs at four different frequency bands are estimated and used as features. Voiced speech is also filtered with 21 critical-bandpass filters that mimic the human auditory neurons. Normalized energies of these filter outputs are used as another set of features. The results obtained have shown that the HNR and the critical-band energy spectrum can be used to correlate laryngeal pathology and voice alteration, using previously classified voice samples. This method could be an additional acoustic indicator that supplements the clinical diagnostic features for voice evaluation.

  7. 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...

  8. Gravitational potential energy of the earth - A spherical harmonic approach

    NASA Technical Reports Server (NTRS)

    Rubincam, D. P.

    1979-01-01

    A spherical harmonic equation for the gravitational potential energy of the earth is derived for an arbitrary density distribution by conceptually bringing in mass-elements from infinity and building up the earth shell upon spherical shell. The zeroth degree term in the spherical harmonic expansion agrees with the usual expression for the energy of a radial density distribution. The second degree terms give a maximum nonhydrostatic energy in the crust and mantle of -2.77 x 10 to the 29th ergs, an order of magnitude below McKenzie's (1966) estimate. McKenzie's result stems from mathematical error. Our figure is almost identical with Kaula's (1963) estimate of the minimum shear strain energy in the mantle, a not unexpected result on the basis of the virial theorem. If the earth is assumed to be a homogeneous viscous oblate spheroid relaxing to an equilibrium shape, then a lower limit to the mantle viscosity of 1.3 x 10 to the 20th P is found by assuming that the total geothermal flux is due to viscous dissipation of energy. This number is almost six orders of magnitude below MacDonald's (1966) estimate of the viscosity and removes his objection to convection. If the nonequilibrium figure is dynamically maintained by the earth acting as a heat engine at 1% efficiency, then the viscosity is 10 to the 22nd P, a number preferred by Cathles (1975) and Peltier and Andrew (1976) as the viscosity of the mantle.

  9. Rotational Energy Transfer of N2 Gas Determined Using a New Ab Initio Potential Energy Surface

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.; Stallcop, James R.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    Rotational energy transfer between two N2 molecules is a fundamental process of some importance. Exchange is expected to play a role, but its importance is somewhat uncertain. Rotational energy transfer cross sections of N2 also have applications in many other fields including modeling of aerodynamic flows, laser operations, and linewidth analysis in nonintrusive laser diagnostics. A number of N2-N2 rigid rotor potential energy surface (PES) has been reported in the literature.

  10. 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.

  11. Potential for energy conservation in the cement industry

    SciTech Connect

    Garrett-Price, B.A.

    1985-02-01

    This report assesses the potential for energy conservation in the cement industry. Energy consumption per ton of cement decreased 20% between 1972 and 1982. During this same period, the cement industry became heavily dependent on coal and coke as its primary fuel source. Although the energy consumed per ton of cement has declined markedly in the past ten years, the industry still uses more than three and a half times the fuel that is theoretically required to produce a ton of clinker. Improving kiln thermal efficiency offers the greatest opportunity for saving fuel. Improving the efficiency of finish grinding offers the greatest potential for reducing electricity use. Technologies are currently available to the cement industry to reduce its average fuel consumption per ton by product by as much as 40% and its electricity consumption per ton by about 10%. The major impediment to adopting these technologies is the cement industry's lack of capital as a result of low or no profits in recent years.

  12. Theoretical studies of potential energy surfaces and computational methods.

    SciTech Connect

    Shepard, R.

    2006-01-01

    This project involves the development, implementation, and application of theoretical methods for the calculation and characterization of potential energy surfaces (PES) involving molecular species that occur in hydrocarbon combustion. These potential energy surfaces require an accurate and balanced treatment of reactants, intermediates, and products. Most of our work focuses on general multiconfiguration self-consistent-field (MCSCF) and multireference single- and double-excitation configuration interaction (MRSDCI) methods. In contrast to the more common single-reference electronic structure methods, this approach is capable of describing accurately molecular systems that are highly distorted away from their equilibrium geometries, including reactant, fragment, and transition-state geometries, and of describing regions of the potential surface that are associated with electronic wave functions of widely varying nature. The MCSCF reference wave functions are designed to be sufficiently flexible to describe qualitatively the changes in the electronic structure over the broad range of molecular geometries of interest. The necessary mixing of ionic, covalent, and Rydberg contributions, along with the appropriate treatment of the different electron-spin components (e.g. closed shell, high-spin open-shell, low-spin open shell, radical, diradical, etc.) of the wave functions are treated correctly at this level. Further treatment of electron correlation effects is included using large scale multireference CI wave functions, particularly including the single and double excitations relative to the MCSCF reference space. This leads to the most flexible and accurate large-scale MRSDCI wave functions that have been used to date in global PES studies.

  13. Potential environmental effects of energy conservation measures in northwest industries

    SciTech Connect

    Baechler, M C; Gygi, K F; Hendrickson, P L

    1992-01-01

    The Bonneville Power Administration (Bonneville) has identified 101 plants in the Pacific Northwest that account for 80% of the region's industrial electricity consumption. These plants offer a precise target for a conservation program. PNL determined that most of these 101 plants were represented by 11 major industries. We then reviewed 36 major conservation technologies used in these 11 industrial settings to determine their potential environmental impacts. Energy efficiency technologies designed for industrial use may result in direct or indirect environmental impacts. Effects may result from the production of the conservation measure technology, changes in the working environment due to different energy and material requirements, or changes to waste streams. Industry type, work-place conditions, worker training, and environmental conditions inside and outside the plant are all key variables that may affect environmental outcomes. To address these issues this report has three objectives: Describe potential conservation measures that Bonneville may employ in industrial programs and discuss potential primary impacts. Characterize industrial systems and processes where the measure may be employed and describe general environmental issues associated with each industry type. Review environmental permitting, licensing, and other regulatory actions required for industries and summarize the type of information available from these sources for further analysis.

  14. Potential impacts of nanotechnology on energy transmission applications and needs.

    SciTech Connect

    Elcock, D.; Environmental Science Division

    2007-11-30

    The application of nanotechnologies to energy transmission has the potential to significantly impact both the deployed transmission technologies and the need for additional development. This could be a factor in assessing environmental impacts of right-of-way (ROW) development and use. For example, some nanotechnology applications may produce materials (e.g., cables) that are much stronger per unit volume than existing materials, enabling reduced footprints for construction and maintenance of electricity transmission lines. Other applications, such as more efficient lighting, lighter-weight materials for vehicle construction, and smaller batteries having greater storage capacities may reduce the need for long-distance transport of energy, and possibly reduce the need for extensive future ROW development and many attendant environmental impacts. This report introduces the field of nanotechnology, describes some of the ways in which processes and products developed with or incorporating nanomaterials differ from traditional processes and products, and identifies some examples of how nanotechnology may be used to reduce potential ROW impacts. Potential environmental, safety, and health impacts are also discussed.

  15. Theoretical studies of potential energy surfaces and computational methods

    SciTech Connect

    Shepard, R.

    1993-12-01

    This project involves the development, implementation, and application of theoretical methods for the calculation and characterization of potential energy surfaces involving molecular species that occur in hydrocarbon combustion. These potential energy surfaces require an accurate and balanced treatment of reactants, intermediates, and products. This difficult challenge is met with general multiconfiguration self-consistent-field (MCSCF) and multireference single- and double-excitation configuration interaction (MRSDCI) methods. In contrast to the more common single-reference electronic structure methods, this approach is capable of describing accurately molecular systems that are highly distorted away from their equilibrium geometries, including reactant, fragment, and transition-state geometries, and of describing regions of the potential surface that are associated with electronic wave functions of widely varying nature. The MCSCF reference wave functions are designed to be sufficiently flexible to describe qualitatively the changes in the electronic structure over the broad range of geometries of interest. The necessary mixing of ionic, covalent, and Rydberg contributions, along with the appropriate treatment of the different electron-spin components (e.g. closed shell, high-spin open-shell, low-spin open shell, radical, diradical, etc.) of the wave functions, are treated correctly at this level. Further treatment of electron correlation effects is included using large scale multireference CI wave functions, particularly including the single and double excitations relative to the MCSCF reference space. This leads to the most flexible and accurate large-scale MRSDCI wave functions that have been used to date in global PES studies.

  16. Acoustic and perceptual correlates of syllable weight

    NASA Astrophysics Data System (ADS)

    Gordon, Matthew; Jany, Carmen; Nash, Carlos

    2005-09-01

    Differences between languages in the stress-attracting properties of various syllable types (syllable weight) are associated with phonetic differences. Certain languages that preferentially stress CVC syllables (i.e., treat CVC as heavy) fail to display substantial vowel shortening in CVC, unlike languages that treat CVC as non-stress-attracting or light [Broselow et al. (1997)]. Furthermore, CVC has greater energy (intensity integrated over time) in languages in which it is heavy relative to languages with light CVC [Gordon (2002)]. This paper compares multiple potential acoustic and perceptual correlates of syllable weight. A representative cross section of syllable types in words uttered by speakers of four languages was recorded. In two languages (Arabic, Hindi), CVC is heavy; in two languages (Mongolian, Malayalam), CVC is light. Three measurements were taken: duration of the syllable rime, acoustic intensity integrated over the rime, and a measure of perceptual energy of the rime incorporating various factors (e.g., temporal integration and adaptation, bandpass filtering). Results thus far indicate that a measure of prominence factoring in both intensity and duration better distinguishes languages on the basis of weight criterion than a simple measure of duration. The perceptual energy measure provides a slightly better fit than acoustic energy. [Work supported by NSF.

  17. ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS: Symmetry Analysis of Barotropic Potential Vorticity Equation

    NASA Astrophysics Data System (ADS)

    Bihlo, Alexander; Popovych, Roman O.

    2009-10-01

    Recently F. Huang [Commun. Theor. Phys. 42 (2004) 903] and X. Tang and P.K. Shukla [Commun. Theor. Phys. 49 (2008) 229] investigated symmetry properties of the barotropic potential vorticity equation without forcing and dissipation on the beta-plane. This equation is governed by two dimensionless parameters, F and β, representing the ratio of the characteristic length scale to the Rossby radius of deformation and the variation of earth' angular rotation, respectively. In the present paper it is shown that in the case F ≠ 0 there exists a well-defined point transformation to set β = 0. The classification of one- and two-dimensional Lie subalgebras of the Lie symmetry algebra of the potential vorticity equation is given for the parameter combination F ≠ 0 and β = 0. Based upon this classification, distinct classes of group-invariant solutions are obtained and extended to the case β ≠ 0.

  18. Competition between inverse piezoelectric effect and deformation potential mechanism in undoped GaAs revealed by ultrafast acoustics

    NASA Astrophysics Data System (ADS)

    Vaudel, G.; Ruello, P.; Pezeril, T.; Gusev, V.

    2013-03-01

    By using the picosecond ultrasonics technique, piezoelectric effect in <111> GaAs undoped sample at both faces (A[111] and B[-1-1-1]) is experimentally studied. We demonstrate that piezoelectric generation of sound can dominate in <111> GaAs material over the deformation potential mechanism even in the absence of static externally applied or built-in electric field in the semiconductor material. In that case, the Dember field, caused by the separation of photo-generated electrons and holes in the process of supersonic diffusion, is sufficient for the dominance of the piezoelectric mechanism during the optoacoustic excitation. The experimental results on the sample at both faces reveal that in one case (A face), the two mechanisms, piezoelectric effect and deformation potential, can compensate each other leading to a large decrease of the measured Brillouin oscillation magnitude.

  19. Acoustic agglomeration methods and apparatus

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B. (Inventor)

    1984-01-01

    Methods are described for using acoustic energy to agglomerate fine particles on the order of one micron diameter that are suspended in gas, to provide agglomerates large enough for efficient removal by other techniques. The gas with suspended particles, is passed through the length of a chamber while acoustic energy at a resonant chamber mode is applied to set up one or more acoustic standing wave patterns that vibrate the suspended particles to bring them together so they agglomerate. Several widely different frequencies can be applied to efficiently vibrate particles of widely differing sizes. The standing wave pattern can be applied along directions transversed to the flow of the gas. The particles can be made to move in circles by applying acoustic energy in perpendicular directions with the energy in both directions being of the same wavelength but 90 deg out of phase.

  20. Nuclear binding energy and symmetry energy of nuclear matter with modern nucleon-nucleon potentials

    SciTech Connect

    Hassaneen, Kh.S.A.; Abo-Elsebaa, H.M.; Sultan, E.A.; Mansour, H.M.M.

    2011-03-15

    Research Highlights: > The nuclear matter is studied within the Brueckner-Hartree-Fock (BHF) approach employing the most recent accurate nucleon-nucleon potentials. > The results come out by approximating the single particle self-consistent potential with a parabolic form. > We discuss the current status of the Coester line, i.e., density and energy of the various saturation points being strongly linearly correlated. > The nuclear symmetry energy is calculated as the difference between the binding energy of pure neutron matter and that of symmetric nuclear matter. - Abstract: The binding energy of nuclear matter at zero temperature in the Brueckner-Hartree-Fock approximation with modern nucleon-nucleon potentials is studied. Both the standard and continuous choices of single particle energies are used. These modern nucleon-nucleon potentials fit the deuteron properties and are phase shifts equivalent. Comparison with other calculations is made. In addition we present results for the symmetry energy obtained with different potentials, which is of great importance in astrophysical calculation.

  1. 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.

  2. Backcoupling of acoustic streaming on the temperature field inside high-intensity discharge lamps

    NASA Astrophysics Data System (ADS)

    Schwieger, J.; Baumann, B.; Wolff, M.; Manders, F.; Suijker, J.

    2015-11-01

    Operating high-intensity discharge lamps in the high frequency range (20-300 kHz) provides energy-saving and cost reduction potentials. However, commercially available lamp drivers do not make use of this operating strategy because light intensity fluctuations and even lamp destruction are possible. The reason for the fluctuating discharge arc are acoustic resonances in this frequency range that are excited in the arc tube. The acoustic resonances in turn generate a fluid flow that is caused by the acoustic streaming effect. Here, we present a 3D multiphysics model to determine the influence of acoustic streaming on the temperature field in the vicinity of an acoustic eigenfrequency. In that case a transition from stable to instable behavior occurs. The model is able to predict when light flicker can be expected. The results are in very good accordance with accompanying experiments.

  3. Smart DNA Fabrication Using Sound Waves: Applying Acoustic Dispensing Technologies to Synthetic Biology.

    PubMed

    Kanigowska, Paulina; Shen, Yue; Zheng, Yijing; Rosser, Susan; Cai, Yizhi

    2016-02-01

    Acoustic droplet ejection (ADE) technology uses focused acoustic energy to transfer nanoliter-scale liquid droplets with high precision and accuracy. This noncontact, tipless, low-volume dispensing technology minimizes the possibility of cross-contamination and potentially reduces the costs of reagents and consumables. To date, acoustic dispensers have mainly been used in screening libraries of compounds. In this paper, we describe the first application of this powerful technology to the rapidly developing field of synthetic biology, for DNA synthesis and assembly at the nanoliter scale using a Labcyte Echo 550 acoustic dispenser. We were able to successfully downscale PCRs and the popular one-pot DNA assembly methods, Golden Gate and Gibson assemblies, from the microliter to the nanoliter scale with high assembly efficiency, which effectively cut the reagent cost by 20- to 100-fold. We envision that acoustic dispensing will become an instrumental technology in synthetic biology, in particular in the era of DNA foundries. PMID:26163567

  4. 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.

  5. Electrostatic potentials and energy loss due to a projectile propagating through a non-Maxwellian dusty plasma

    SciTech Connect

    Deeba, F.; Ahmad, Zahoor; Murtaza, G.

    2006-08-15

    The electrostatic potentials (Debye and wake) and energy loss due to a charged projectile propagating through an unmagnetized collisionless dusty plasma are derived employing kappa and generalized (r,q) velocity distributions for the dust acoustic wave. It is found that these quantities in general differ from their Maxwellian counterparts and are sensitive to the values of spectral index, {kappa} in the case of kappa distribution and to r, q in the case of generalized (r,q) distribution. The amplitudes of these quantities are less for small values of the spectral index ({kappa}, r=0, q) but approach the Maxwellian in the limit {kappa}{yields}{infinity} (for kappa distribution) and for r=0, q{yields}{infinity} [for generalized (r,q) distribution]. For any nonzero value of r, the potential and the energy loss grow beyond the Maxwellian results. The effect of kappa and generalized (r,q) distributions on potential and energy loss is also studied numerically and the results are compared with those of the Maxwellian distribution.

  6. Potential for energy savings in old and new auto engines

    NASA Astrophysics Data System (ADS)

    Reitz, John R.

    1985-11-01

    This paper disucsses the potential for energy savings in the transportation sector through the use of both improved and entirely new automotive engines. Although spark-ignition and diesel internal combustion engines will remain the dominant choices for passenger-car use throughout the rest of this century, improved versions of these engines (lean-burn, low-friction spark-ignition and adiabatic, low-friction diesel engines) could, in the long term, provide a 20-30 percent improvement in fuel economy over what is currently available. The use of new materials, and modifications to both vehicle structure and vehicle transmissions may yield further improvements. Over a longer time frame, the introduction of the high-temperature gas-turbine engine and the use of new synfuels may provide further opportunities for energy conservation.

  7. Ab initio potential energy surface and rovibrational states of HBO

    NASA Astrophysics Data System (ADS)

    Ha, Tae-Kyu; Makarewicz, Jan

    1999-01-01

    The potential energy surface describing the large-amplitude motion of H around the BO core in the HBO molecule has been determined from ab initio calculations. This surface has been sampled by a set of 170 grid points from a two-dimensional space defined by the stretching and the bending coordinates of the H nucleus. At each grid point, the BO bond length has been optimized using the second-order Møller-Plesset perturbation theory with the basis set aug-cc-pVTZ. The surface has a local minimum for the linear as well as the bent configuration of HBO. A low energy barrier to the linear configuration BOH causes a large-amplitude motion and a strong rovibrational interaction in the molecule. Its rovibrational dynamics is different from the dynamics in bent or quasilinear triatomic molecules.

  8. Finite field-energy and interparticle potential in logarithmic electrodynamics

    NASA Astrophysics Data System (ADS)

    Gaete, Patricio; Helayël-Neto, José

    2014-03-01

    We pursue an investigation of logarithmic electrodynamics, for which the field energy of a point-like charge is finite, as happens in the case of the usual Born-Infeld electrodynamics. We also show that, contrary to the latter, logarithmic electrodynamics exhibits the feature of birefringence. Next, we analyze the lowest-order modifications for both logarithmic electrodynamics and for its non-commutative version, within the framework of the gauge-invariant path-dependent variables formalism. The calculation shows a long-range correction (-type) to the Coulomb potential for logarithmic electrodynamics. Interestingly enough, for its non-commutative version, the interaction energy is ultraviolet finite. We highlight the role played by the new quantum of length in our analysis.

  9. Stabilized quasi-Newton optimization of noisy potential energy surfaces

    NASA Astrophysics Data System (ADS)

    Schaefer, Bastian; Ghasemi, S. Alireza; Roy, Shantanu; Goedecker, Stefan; Goedecker Group Team

    Optimizations of atomic positions belong to the most frequently performed tasks in electronic structure calculations. Many simulations like global minimum searches or the identification of chemical reaction pathways can require the computation of hundreds or thousands of minimizations or saddle points. To automatize these tasks, optimization algorithms must not only be efficient but also very reliable. Unfortunately, computational noise in forces and energies is inherent to electronic structure codes. This computational noise poses a severe problem to the stability of efficient optimization methods like the limited-memory Broyden-Fletcher-Goldfarb-Shanno algorithm. In this talk a recently published technique that allows to obtain significant curvature information of noisy potential energy surfaces is presented. This technique was used to construct both, a stabilized quasi-Newton minimization method and a stabilized quasi-Newton saddle finding approach. With the help of benchmarks both the minimizer and the saddle finding approach were demonstrated to be superior to comparable existing methods.

  10. Calorific evaluation and energy potential of grape pomace

    NASA Astrophysics Data System (ADS)

    Burg, Patrik; Ludín, David; Rutkowski, Kazimierz; Krakowiak-Bal, Anna; Trávníček, Petr; Zemánek, Pavel; Turan, Jan; Višacki, Vladimir

    2016-04-01

    This article deals with energetic evaluation and potential of pomace - a waste product originating during production of grape wine. Calorimetric analysis of 19 grapevine varieties was performed in 2013 and 2014. The aim was to specify their combustible limit and the gross calorific value. The evaluations were performed on pristine pomace, pomace without seeds, and only on seeds themselves. The results obtained imply that pomace is an interesting energetic resource with a gross calorific value of 16.07-18.97 MJ kg-1. Lower calorific values were detected in pomace after seed separation ie 14.60-17.75 MJ kg-1; on the contrary, seeds alone had the highest calorific values of 19.78-21.13 MJ kg-1. It can be assumed from the results of energetic evaluation of pomace in Czech Republic conditions that, by purposeful and efficient usage of pomace, 6.4 GWh of electric energy and 28 GWh of thermal energy can be generated.

  11. Assessing geothermal energy potential in upstate New York. Final report

    SciTech Connect

    Hodge, D.S.

    1996-08-01

    The potential of geothermal energy for future electric power generation in New York State is evaluated using estimates of temperatures of geothermal reservoir rocks. Bottom hole temperatures from over 2000 oil and gas wells in the region were integrated into subsurface maps of the temperatures for specific geothermal reservoirs. The Theresa/Potsdam formation provides the best potential for extraction of high volumes of geothermal fluids. The evaluation of the Theresa/Potsdam geothermal reservoir in upstate New York suggests that an area 30 miles east of Elmira, New York has the highest temperatures in the reservoir rock. The Theresa/Potsdam reservoir rock should have temperatures about 136 {degrees}C and may have as much as 450 feet of porosity in excess of 8%. Estimates of the volumes of geothermal fluids that can be extracted are provided and environmental considerations for production from a geothermal well is discussed.

  12. Potential energy surfaces and reaction dynamics of polyatomic molecules

    SciTech Connect

    Chang, Yan-Tyng.

    1991-11-01

    A simple empirical valence bond (EVB) model approach is suggested for constructing global potential energy surfaces for reactions of polyatomic molecular systems. This approach produces smooth and continuous potential surfaces which can be directly utilized in a dynamical study. Two types of reactions are of special interest, the unimolecular dissociation and the unimolecular isomerization. For the first type, the molecular dissociation dynamics of formaldehyde on the ground electronic surface is investigated through classical trajectory calculations on EVB surfaces. The product state distributions and vector correlations obtained from this study suggest very similar behaviors seen in the experiments. The intramolecular hydrogen atom transfer in the formic acid dimer is an example of the isomerization reaction. High level ab initio quantum chemistry calculations are performed to obtain optimized equilibrium and transition state dimer geometries and also the harmonic frequencies.

  13. Dark Energy:. the Absolute Electric Potential of the Universe

    NASA Astrophysics Data System (ADS)

    Jiménez, Jose Beltrán; Maroto, Antonio L.

    Is there an absolute cosmic electric potential? The recent discovery of the accelerated expansion of the universe could be indicating that this is certainly the case. In this essay we show that the consistency of the covariant and gauge-invariant theory of electromagnetism is truly questionable when considered on cosmological scales. Out of the four components of the electromagnetic field, Maxwell's theory contains only two physical degrees of freedom. However, in the presence of gravity, one of the "unphysical" states cannot be consistently eliminated, thus becoming real. This third polarization state is completely decoupled from charged matter, but can be excited gravitationally, thus breaking gauge invariance. On large scales the new state can be seen as a homogeneous cosmic electric potential, whose energy density behaves as a cosmological constant.

  14. Global Expression for Representing Diatomic Potential-Energy Curves

    NASA Technical Reports Server (NTRS)

    Ferrante, John; Schlosser, Herbert; Smith, John R.

    1991-01-01

    A three-parameter expression that gives an accurate fit to diatomic potential curves over the entire range of separation for charge transfers between 0 and 1. It is based on a generalization of the universal binding-energy relation of Smith et al. (1989) with a modification that describes the crossover from a partially ionic state to the neutral state at large separations. The expression is tested by comparison with first-principles calculations of the potential curves ranging from covalently bonded to ionically bonded. The expression is also used to calculate spectroscopic constants form a curve fit to the first-principles curves. A comparison is made with experimental values of the spectroscopic constants.

  15. Potential energy curves and collision integrals of air components

    NASA Technical Reports Server (NTRS)

    Partridge, Harry; Stallcop, James R.; Levin, Eugene; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    Collision integrals are fundamental quantities required to determine the transport properties of the environment surrounding aerospace vehicles in the upper atmosphere. These collision integrals can be determined as a function of temperature from the potential energy curves describing the atomic and molecular collisions. Ab initio calculations provide a practical method of computing the required interaction potentials. In this work we will discuss recent advances with an emphasis on the accuracy that is obtainable. Results for interactions, e.g. N+N, N+O, O+O, and H+N2 will be reviewed and their application to the determination of transport properties, such as diffusion and viscosity coefficients, will be examined.

  16. ACOUSTIC RECTIFICATION IN DISPERSIVE MEDIA

    SciTech Connect

    Cantrell, John H.

    2009-03-03

    It is shown that the shapes of acoustic radiation-induced static strain and displacement pulses (rectified acoustic pulses) are defined locally by the energy density of the generating waveform. Dispersive properties are introduced analytically by assuming that the rectified pulses are functionally dependent on a phase factor that includes both dispersive and nonlinear terms. The dispersion causes an evolutionary change in the shape of the energy density profile that leads to the generation of solitons experimentally observed in fused silica.

  17. Acoustic Rectification in Dispersive Media

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.

    2008-01-01

    It is shown that the shapes of acoustic radiation-induced static strain and displacement pulses (rectified acoustic pulses) are defined locally by the energy density of the generating waveform. Dispersive properties are introduced analytically by assuming that the rectified pulses are functionally dependent on a phase factor that includes both dispersive and nonlinear terms. The dispersion causes an evolutionary change in the shape of the energy density profile that leads to the generation of solitons experimentally observed in fused silica.

  18. Terahertz absorption spectra and potential energy distribution of liquid crystals.

    PubMed

    Chen, Zezhang; Jiang, Yurong; Jiang, Lulu; Ma, Heng

    2016-01-15

    In this work, the terahertz (THz) absorption spectra of a set of nematic liquid crystals were studied using the density functional theories (DFT). An accurate assignment of the vibrational modes corresponding to absorption frequencies were performed using potential energy distribution (PED) in a frequency range of 0-3 THz. The impacts of different core structures on THz absorption spectra were discussed. The results indicate that scope of application must be considered in the LC-based THz device designing. This proposed work may give a useful suggestion on the design of novel liquid crystal material in THz wave. PMID:26476072

  19. Freezing of Energy of a Soliton in an External Potential

    NASA Astrophysics Data System (ADS)

    Bambusi, D.; Maspero, A.

    2016-05-01

    In this paper we study the dynamics of a soliton in the generalized NLS with a small external potential ɛV of Schwartz class. We prove that there exists an effective mechanical system describing the dynamics of the soliton and that, for any positive integer r, the energy of such a mechanical system is almost conserved up to times of order ɛ - r . In the rotational invariant case we deduce that the true orbit of the soliton remains close to the mechanical one up to times of order ɛ - r .

  20. Size dependence of vacancy migration energy in ionic nano particles: A potential energy landscape perspective

    NASA Astrophysics Data System (ADS)

    Niiyama, Tomoaki; Okushima, Teruaki; Ikeda, Kensuke S.; Shimizu, Yasushi

    2016-06-01

    Size dependence of vacancy migration energy in ionic nano particles is investigated by analysis of potential energy surfaces in potassium chloride clusters. Numerical methods are used to find almost all local minima and transition states for vacancy migration in clusters of different sizes, and reveal characteristic features of energy surface structure. It is shown that migration energy is significantly lower near a cluster surface than near a cluster core, and the mean first-passage time for migration of a vacancy decreases with cluster size. These results are consistent with observations of high diffusion rates in small clusters.

  1. A satellite investigation of energy flux and inferred potential drop in auroral electron energy spectra

    NASA Technical Reports Server (NTRS)

    Menietti, J. D.; Burch, J. L.

    1981-01-01

    The relationship between auroral electron energy flux and the inferred accelerating potential drop for accelerated Maxwellian distributions is investigated on the basis of Atmospheric Explorer D spectral measurements. An analytical approximation for the total downward energy flux carried by an isotropic Maxwellian electron population accelerated by a field-aligned electrostatic potential drop is derived which is valid for values of the electron energy/characteristic accelerated Maxwellian distribution energy which are less than the difference between the ratio of the magnetic field strengths at the altitude of observation and the altitude of potential drop, and unity. Data from the Low Energy Electron Experiment on board AE D obtained on both the dayside and the nightside during periods of significant inverted-V type electron precipitation shows that the 455 energy spectra considered, 160 of them, obtained between 60 and 85 deg invariant latitude, could be fit to accelerated Maxwellian distributions. The 160 Maxwellian spectra are then shown to be in agreement with the predictions of the accelerated Maxwellian model. Finally, analysis of individual spectra suggests that the altitude of the inferred potential drop is at a maximum near the center of the inverted-V structures.

  2. Steam systems in industry: Energy use and energy efficiency improvement potentials

    SciTech Connect

    Einstein, Dan; Worrell, Ernst; Khrushch, Marta

    2001-07-22

    Steam systems are a part of almost every major industrial process today. Thirty-seven percent of the fossil fuel burned in US industry is burned to produce steam. In this paper we will establish baseline energy consumption for steam systems. Based on a detailed analysis of boiler energy use we estimate current energy use in boilers in U.S. industry at 6.1 Quads (6.4 EJ), emitting almost 66 MtC in CO{sub 2} emissions. We will discuss fuels used and boiler size distribution. We also describe potential savings measures, and estimate the economic energy savings potential in U.S. industry (i.e. having payback period of 3 years or less). We estimate the nationwide economic potential, based on the evaluation of 16 individual measures in steam generation and distribution. The analysis excludes the efficient use of steam and increased heat recovery. Based on the analysis we estimate the economic potential at 18-20% of total boiler energy use, resulting in energy savings approximately 1120-1190 TBtu ( 1180-1260 PJ). This results in a reduction of CO{sub 2} emissions equivalent to 12-13 MtC.

  3. Energy life cycle assessment of rice straw bio-energy derived from potential gasification technologies.

    PubMed

    Shie, Je-Lueng; Chang, Ching-Yuan; Chen, Ci-Syuan; Shaw, Dai-Gee; Chen, Yi-Hung; Kuan, Wen-Hui; Ma, Hsiao-Kan

    2011-06-01

    To be a viable alternative, a biofuel should provide a net energy gain and be capable of being produced in large quantities without reducing food supplies. Amounts of agricultural waste are produced and require treatment, with rice straw contributing the greatest source of such potential bio-fuel in Taiwan. Through life-cycle accounting, several energy indicators and four potential gasification technologies (PGT) were evaluated. The input energy steps for the energy life cycle assessment (ELCA) include collection, generator, torrefaction, crushing, briquetting, transportation, energy production, condensation, air pollution control and distribution of biofuels to the point of end use. Every PGT has a positive energy benefit. The input of energy required for the transportation and pre-treatment are major steps in the ELCA. On-site briquetting of refused-derived fuel (RDF) provides an alternative means of reducing transportation energy requirements. Bio-energy sources, such as waste rice straw, provide an ideal material for the bio-fuel plant. PMID:21507625

  4. An Ab Initio Based Potential Energy Surface for Water

    NASA Technical Reports Server (NTRS)

    Partridge, Harry; Schwenke, David W.; Langhoff, Stephen R. (Technical Monitor)

    1996-01-01

    We report a new determination of the water potential energy surface. A high quality ab initio potential energy surface (PES) and dipole moment function of water have been computed. This PES is empirically adjusted to improve the agreement between the computed line positions and those from the HITRAN 92 data base. The adjustment is small, nonetheless including an estimate of core (oxygen 1s) electron correlation greatly improves the agreement with experiment. Of the 27,245 assigned transitions in the HITRAN 92 data base for H2(O-16), the overall root mean square (rms) deviation between the computed and observed line positions is 0.125/cm. However the deviations do not correspond to a normal distribution: 69% of the lines have errors less than 0.05/cm. Overall, the agreement between the line intensities computed in the present work and those contained in the data base is quite good, however there are a significant number of line strengths which differ greatly.

  5. Colloidal particles driven across periodic optical-potential-energy landscapes

    NASA Astrophysics Data System (ADS)

    Juniper, Michael P. N.; Straube, Arthur V.; Aarts, Dirk G. A. L.; Dullens, Roel P. A.

    2016-01-01

    We study the motion of colloidal particles driven by a constant force over a periodic optical potential energy landscape. First, the average particle velocity is found as a function of the driving velocity and the wavelength of the optical potential energy landscape. The relationship between average particle velocity and driving velocity is found to be well described by a theoretical model treating the landscape as sinusoidal, but only at small trap spacings. At larger trap spacings, a nonsinusoidal model for the landscape must be used. Subsequently, the critical velocity required for a particle to move across the landscape is determined as a function of the wavelength of the landscape. Finally, the velocity of a particle driven at a velocity far exceeding the critical driving velocity is examined. Both of these results are again well described by the two theoretical routes for small and large trap spacings, respectively. Brownian motion is found to have a significant effect on the critical driving velocity but a negligible effect when the driving velocity is high.

  6. Computer simulations of glasses: the potential energy landscape

    NASA Astrophysics Data System (ADS)

    Raza, Zamaan; Alling, Björn; Abrikosov, Igor A.

    2015-07-01

    We review the current state of research on glasses, discussing the theoretical background and computational models employed to describe them. This article focuses on the use of the potential energy landscape (PEL) paradigm to account for the phenomenology of glassy systems, and the way in which it can be applied in simulations and the interpretation of their results. This article provides a broad overview of the rich phenomenology of glasses, followed by a summary of the theoretical frameworks developed to describe this phenomonology. We discuss the background of the PEL in detail, the onerous task of how to generate computer models of glasses, various methods of analysing numerical simulations, and the literature on the most commonly used model systems. Finally, we tackle the problem of how to distinguish a good glass former from a good crystal former from an analysis of the PEL. In summarising the state of the potential energy landscape picture, we develop the foundations for new theoretical methods that allow the ab initio prediction of the glass-forming ability of new materials by analysis of the PEL.

  7. Computer simulations of glasses: the potential energy landscape.

    PubMed

    Raza, Zamaan; Alling, Björn; Abrikosov, Igor A

    2015-07-29

    We review the current state of research on glasses, discussing the theoretical background and computational models employed to describe them. This article focuses on the use of the potential energy landscape (PEL) paradigm to account for the phenomenology of glassy systems, and the way in which it can be applied in simulations and the interpretation of their results. This article provides a broad overview of the rich phenomenology of glasses, followed by a summary of the theoretical frameworks developed to describe this phenomonology. We discuss the background of the PEL in detail, the onerous task of how to generate computer models of glasses, various methods of analysing numerical simulations, and the literature on the most commonly used model systems. Finally, we tackle the problem of how to distinguish a good glass former from a good crystal former from an analysis of the PEL. In summarising the state of the potential energy landscape picture, we develop the foundations for new theoretical methods that allow the ab initio prediction of the glass-forming ability of new materials by analysis of the PEL. PMID:26139691

  8. Microscopically derived potential energy surfaces from mostly structural considerations

    NASA Astrophysics Data System (ADS)

    Ermamatov, M. J.; Hess, Peter O.

    2016-08-01

    A simple procedure to estimate the quadrupole Potential-Energy-Surface (PES) is presented, using mainly structural information, namely the content of the shell model space and the Pauli exclusion principle. Further microscopic properties are implicitly contained through the use of results from the Möller and Nix tables or experimental information. A mapping to the geometric potential is performed yielding the PES. The General Collective Model is used in order to obtain an estimate on the spectrum and quadrupole transitions, adjusting only the mass parameter. First, we test the conjecture on known nuclei, deriving the PES and compare them to known data. We will see that the PES approximates very well the structure expected. Having acquired a certain confidence, we predict the PES of several chain of isotopes of heavy and super-heavy nuclei and at the end we investigate the structure of nuclei in the supposed island of stability. One of the main points to show is that simple assumptions can provide already important information on the structure of nuclei outside known regions and that spectra and electromagnetic transitions can be estimated without using involved calculations and assumptions. The procedure does not allow to calculate binding energies. The method presented can be viewed as a starting point for further improvements.

  9. Complex potential and bottomonium suppression at LHC energy

    NASA Astrophysics Data System (ADS)

    Kakade, Uttam; Patra, Binoy Krishna; Thakur, Lata

    2015-03-01

    We have studied the thermal suppression of the bottomonium states in relativistic heavy-ion collision at LHC energies as function of centrality, rapidity, transverse momentum. First, we address the effects of the nonperturbative confining force and the momentum anisotropy together on heavy quark potential at finite temperature, which are resolved by correcting both the perturbative and nonperturbative terms of the potential at T = 0 in a weakly-anisotropic medium, not its perturbative term alone as usually done in the literature. Second, we model the expansion of medium by the Bjorken hydrodynamics in the presence of both shear and bulk viscosity, followed by an additional pre-equilibrium anisotropic evolution. Finally, we couple them together to quantify the yields of bottomonium production in nucleus-nucleus collisions at LHC energies and found a better agreement with the CMS data. Our estimate of the inclusive ϒ(1S) production indirectly constrains both the uncertainties in isotropization time and the shear-to-entropy density ratio and favors the values as 0.3 fm/c and 0.3 (perturbative result), respectively.

  10. 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.

  11. Direct computation of general chemical energy differences: Application to ionization potentials, excitation, and bond energies

    SciTech Connect

    Beste, Ariana; Harrison, Robert J; Yanai, Takeshi

    2006-01-01

    Chemists are mainly interested in energy differences. In contrast, most quantum chemical methods yield the total energy which is a large number compared to the difference and has therefore to be computed to a higher relative precision than would be necessary for the difference alone. Hence, it is desirable to compute energy differences directly, thereby avoiding the precision problem. Whenever it is possible to find a parameter which transforms smoothly from an initial to a final state, the energy difference can be obtained by integrating the energy derivative with respect to that parameter (c.f., thermodynamic integration or adiabatic connection methods). If the dependence on the parameter is predominantly linear, accurate results can be obtained by single-point integration. In density functional theory (DFT) and Hartree-Fock, we applied the formalism to ionization potentials, excitation energies, and chemical bond breaking. Example calculations for ionization potentials and excitation energies showed that accurate results could be obtained with a linear estimate. For breaking bonds, we introduce a non-geometrical parameter which gradually turns the interaction between two fragments of a molecule on. The interaction changes the potentials used to determine the orbitals as well as constraining the orbitals to be orthogonal.

  12. Direct computation of general chemical energy differences: Application to ionization potentials, excitation, and bond energies

    NASA Astrophysics Data System (ADS)

    Beste, A.; Harrison, R. J.; Yanai, T.

    2006-08-01

    Chemists are mainly interested in energy differences. In contrast, most quantum chemical methods yield the total energy which is a large number compared to the difference and has therefore to be computed to a higher relative precision than would be necessary for the difference alone. Hence, it is desirable to compute energy differences directly, thereby avoiding the precision problem. Whenever it is possible to find a parameter which transforms smoothly from an initial to a final state, the energy difference can be obtained by integrating the energy derivative with respect to that parameter (cf. thermodynamic integration or adiabatic connection methods). If the dependence on the parameter is predominantly linear, accurate results can be obtained by single-point integration. In density functional theory and Hartree-Fock, we applied the formalism to ionization potentials, excitation energies, and chemical bond breaking. Example calculations for ionization potentials and excitation energies showed that accurate results could be obtained with a linear estimate. For breaking bonds, we introduce a nongeometrical parameter which gradually turns the interaction between two fragments of a molecule on. The interaction changes the potentials used to determine the orbitals as well as the constraint on the orbitals to be orthogonal.

  13. FINAL TECHNICAL REPORT: Underwater Active Acoustic Monitoring Network For Marine And Hydrokinetic Energy Projects

    SciTech Connect

    Stein, Peter J.; Edson, Patrick L.

    2013-12-20

    This project saw the completion of the design and development of a second generation, high frequency (90-120 kHz) Subsurface-Threat Detection Sonar Network (SDSN). The system was deployed, operated, and tested in Cobscook Bay, Maine near the site the Ocean Renewable Power Company TidGen™ power unit. This effort resulted in a very successful demonstration of the SDSN detection, tracking, localization, and classification capabilities in a high current, MHK environment as measured by results from the detection and tracking trials in Cobscook Bay. The new high frequency node, designed to operate outside the hearing range of a subset of marine mammals, was shown to detect and track objects of marine mammal-like target strength to ranges of approximately 500 meters. This performance range results in the SDSN system tracking objects for a significant duration - on the order of minutes - even in a tidal flow of 5-7 knots, potentially allowing time for MHK system or operator decision-making if marine mammals are present. Having demonstrated detection and tracking of synthetic targets with target strengths similar to some marine mammals, the primary hurdle to eventual automated monitoring is a dataset of actual marine mammal kinematic behavior and modifying the tracking algorithms and parameters which are currently tuned to human diver kinematics and classification.

  14. Granular acoustic switches and logic elements

    NASA Astrophysics Data System (ADS)

    Li, Feng; Anzel, Paul; Yang, Jinkyu; Kevrekidis, Panayotis G.; Daraio, Chiara

    2014-10-01

    Electrical flow control devices are fundamental components in electrical appliances and computers; similarly, optical switches are essential in a number of communication, computation and quantum information-processing applications. An acoustic counterpart would use an acoustic (mechanical) signal to control the mechanical energy flow through a solid material. Although earlier research has demonstrated acoustic diodes or circulators, no acoustic switches with wide operational frequency ranges and controllability have been realized. Here we propose and demonstrate an acoustic switch based on a driven chain of spherical particles with a nonlinear contact force. We experimentally and numerically verify that this switching mechanism stems from a combination of nonlinearity and bandgap effects. We also realize the OR and AND acoustic logic elements by exploiting the nonlinear dynamical effects of the granular chain. We anticipate these results to enable the creation of novel acoustic devices for the control of mechanical energy flow in high-performance ultrasonic devices.

  15. Transition Metal Oxide Alloys as Potential Solar Energy Conversion Materials

    SciTech Connect

    Toroker, Maytal; Carter, Emily A.

    2013-02-21

    First-row transition metal oxides (TMOs) are inexpensive potentia alternative materials for solar energy conversion devices. However, some TMOs, such as manganese(II) oxide, have band gaps that are too large for efficiently absorbing solar energy. Other TMOs, such as iron(II) oxide, have conduction and valence band edges with the same orbital character that may lead to unfavorably high electron–hole recombination rates. Another limitation of iron(II) oxide is that the calculated valence band edge is not positioned well for oxidizing water. We predict that key properties, including band gaps, band edge positions, and possibly electron–hole recombination rates, may be improved by alloying TMOs that have different band alignments. A new metric, the band gap center offset, is introduced for simple screening of potential parent materials. The concept is illustrated by calculating the electronic structure of binary oxide alloys that contain manganese, nickel, iron, zinc, and/or magnesium, within density functional theory (DFT)+U and hybrid DFT theories. We conclude that alloys of iron(II) oxide are worth evaluating further as solar energy conversion materials.

  16. Potential contribution of wind energy to climate change mitigation

    NASA Astrophysics Data System (ADS)

    Barthelmie, R. J.; Pryor, S. C.

    2014-08-01

    It is still possible to limit greenhouse gas emissions to avoid the 2 °C warming threshold for dangerous climate change. Here we explore the potential role of expanded wind energy deployment in climate change mitigation efforts. At present, most turbines are located in extra-tropical Asia, Europe and North America, where climate projections indicate continuity of the abundant wind resource during this century. Scenarios from international agencies indicate that this virtually carbon-free source could supply 10-31% of electricity worldwide by 2050 (refs , ). Using these projections within Intergovernmental Panel on Climate Change Representative Concentration Pathway (RCP) climate forcing scenarios, we show that dependent on the precise RCP followed, pursuing a moderate wind energy deployment plan by 2050 delays crossing the 2 °C warming threshold by 1-6 years. Using more aggressive wind turbine deployment strategies delays 2 °C warming by 3-10 years, or in the case of RCP4.5 avoids passing this threshold altogether. To maximize these climate benefits, deployment of non-fossil electricity generation must be coupled with reduced energy use.

  17. Gravitational potential energy of the earth: A spherical harmonic approach

    NASA Technical Reports Server (NTRS)

    Rubincam, D. P.

    1977-01-01

    A spherical harmonic equation for the gravitational potential energy of the earth is derived for an arbitrary density distribution by conceptually bringing in mass-elements from infinity and building up the earth shell upon spherical shell. The zeroth degree term in the spherical harmonic equation agrees with the usual expression for the energy of a radial density distribution. The second degree terms give a maximum nonhydrostatic energy in the mantle and crust of -2.77 x 10 to the twenty-ninth power ergs, an order of magnitude. If the earth is assumed to be a homogeneous viscous oblate spheroid relaxing to an equilibrium shape, then a lower limit to the mantle viscosity of 1.3 x 10 to the twentieth power poises is found by assuming the total geothermal flux is due to viscous dissipation. If the nonequilibrium figure is dynamically maintained by the earth acting as a heat engine at one per cent efficiency, then the viscosity is ten to the twenty second power poises, a number preferred by some as the viscosity of the mantle.

  18. Body Morphology, Energy Stores, and Muscle Enzyme Activity Explain Cricket Acoustic Mate Attraction Signaling Variation

    PubMed Central

    Thomson, Ian R.; Darveau, Charles-A.; Bertram, Susan M.

    2014-01-01

    High mating success in animals is often dependent on males signalling attractively with high effort. Since males should be selected to maximize their reproductive success, female preferences for these traits should result in minimal signal variation persisting in the population. However, extensive signal variation persists. The genic capture hypothesis proposes genetic variation persists because fitness-conferring traits depend on an individual's basic processes, including underlying physiological, morphological, and biochemical traits, which are themselves genetically variable. To explore the traits underlying signal variation, we quantified among-male differences in signalling, morphology, energy stores, and the activities of key enzymes associated with signalling muscle metabolism in two species of crickets, Gryllus assimilis (chirper: <20 pulses/chirp) and G. texensis (triller: >20 pulses/chirp). Chirping G. assimilis primarily fuelled signalling with carbohydrate metabolism: smaller individuals and individuals with increased thoracic glycogen stores signalled for mates with greater effort; individuals with greater glycogen phosphorylase activity produced more attractive mating signals. Conversely, the more energetic trilling G. texensis fuelled signalling with both lipid and carbohydrate metabolism: individuals with increased β-hydroxyacyl-CoA dehydrogenase activity and increased thoracic free carbohydrate content signalled for mates with greater effort; individuals with higher thoracic and abdominal carbohydrate content and higher abdominal lipid stores produced more attractive signals. Our findings suggest variation in male reproductive success may be driven by hidden physiological trade-offs that affect the ability to uptake, retain, and use essential nutrients, although the results remain correlational in nature. Our findings indicate that a physiological perspective may help us to understand some of the causes of variation in behaviour. PMID:24608102

  19. Correlation energy and dispersion interaction in the ab initio potential energy curve of the neon dimer

    SciTech Connect

    Bytautas, L.; Ruedenberg, K.

    2008-06-06

    A close approximation to the empirical potential energy curve of the neon dimer is obtained by coupled-cluster singles plus doubles plus noniterative triples calculations by using nonaugmented correlation-consistent basis sets without counterpoise corrections and complementing them by three-term extrapolations to the complete basis set limit. The potential energy is resolved into a self-consistent-field Hartree-Fock contribution and a correlation contribution. The latter is shown to decay in the long-range region in accordance with the empirical dispersion expansion.

  20. Correlation energy and dispersion interaction in the ab initio potential energy curve of the neon dimer.

    PubMed

    Bytautas, Laimutis; Ruedenberg, Klaus

    2008-06-01

    A close approximation to the empirical potential energy curve of the neon dimer is obtained by coupled-cluster singles plus doubles plus noniterative triples calculations by using nonaugmented correlation-consistent basis sets without counterpoise corrections and complementing them by three-term extrapolations to the complete basis set limit. The potential energy is resolved into a self-consistent-field Hartree-Fock contribution and a correlation contribution. The latter is shown to decay in the long-range region in accordance with the empirical dispersion expansion. PMID:18537423

  1. [Value of early acoustic and somatosensory evoked potentials in monitoring and prognostic assessment of coma in barbiturate therapy--comparison with clinical aspects and EEG].

    PubMed

    Reisecker, F; Witzmann, A; Löffler, W; Leblhuber, F; Deisenhammer, E; Valencak, E

    1987-03-01

    25 comatose patients suffering from severe cerebral lesions of different etiology were examined during barbiturate-therapy by Glasgow-Pittsburg-Coma-Scoring-System (GPCS), EEG, somatosensory and brainstem acoustic evoked potentials. The findings were correlated in view of prognostic prediction and importance for monitoring. A modified form of the Glasgow-Outcome-Score (GOS; independent-survival, dependent-survival, dead) was used for evaluating the outcome. In case of an initial GPCS less than 10 points none of the patients survived, in case of GPCS greater than 10 points 11 out of 19 patients survived. The latter relation of survival was also found in patients with improving or impairing scores during the observation period. In case of initial burst-suppression pattern in the EEG 7 out of 11 patients survived, in case of diffuse abnormalities with or with-out additional focal signs - 4 out of 10 patients survived, but in the latter there was none with an outcome of independent survival. All patients with an isoelectric EEG died. In case of bilateral recording of scalp- SEP 7 out of 11 patients survived, in case of unilateral loss of scalp-EP 4 out of 8 patients survived, but in the latter cases none with an outcome of independence. All patients with initial bilateral failure of scalp-SSEP or loss during the observation period died. In case of bilateral registrable BAEP (wave I to V) 11 out of 17 patients survived. All patients with initial uni- or bilateral failure of those potentials or loss during the observation period died.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3106004

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

    SciTech Connect

    Kaduchak, Gregory; Ward, Michael D

    2014-10-21

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

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

    DOEpatents

    Kaduchak, Gregory; Ward, Michael D.

    2011-12-27

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

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

    DOEpatents

    Kaduchak, Gregory; Ward, Michael D

    2016-05-17

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

  5. The Potential for Renewable Energy Development to Benefit Restoration of the Salton Sea. Analysis of Technical and Market Potential

    SciTech Connect

    Gagne, Douglas; Haase, Scott; Oakleaf, Brett; Hurlbut, David; Akar, Sertac; Wall, Anna; Turchi, Craig; Pienkos, Philip; Melius, Jennifer; Melaina, Marc

    2015-11-01

    This report summarizes the potential for renewable energy development in the Salton Sea region, as well as the potential for revenues from this development to contribute financially to Salton Sea restoration costs. It considers solar, geothermal, biofuels or nutraceutical production from algae pond cultivation, desalination using renewable energy, and mineral recovery from geothermal fluids.


  6. A new local theory of available potential energy for quantifying energy pathways in the oceans

    NASA Astrophysics Data System (ADS)

    Tailleux, Remi

    2013-04-01

    Lorenz's theory of available potential energy (APE) has recently received much attention in the context of ocean energetics, for it is increasingly realized to be a key tool for clarifying the relative importance of the surface buoyancy fluxes in powering the ocean circulation, a controversial issue over the past 15 years or so. So far, however, most recent approaches have been restricted to global APE budgets, often for idealized equations of state, which is arguably of limited interest to understand the precise nature of the energy pathways in the oceans. Here, we will present a local extension of the theory of available potential energy, which is developed for the primitive equations that form the basis of most current general ocean circulation models, and which is valid for an arbitrary nonlinear equation of state. Another advantage of the new theory is that it does not require the reference state underlying Lorenz's APE theory to be necessarily the state of minimum potential energy obtained in an adiabatic re-arrangement of the fluid parcels, and hence does not suffer from traditional difficulties pertaining to how to do the sorting of the fluid parcels. The main result of this work is the ability in some instances to link local conversion of APE into kinetic energy directly to the local production of APE by surface fluxes. The framework is also shown to be useful to provide an energy-based characterization of oceanic water masses.

  7. Improved DFT Potential Energy Surfaces via Improved Densities.

    PubMed

    Kim, Min-Cheol; Park, Hansol; Son, Suyeon; Sim, Eunji; Burke, Kieron

    2015-10-01

    Density-corrected DFT is a method that cures several failures of self-consistent semilocal DFT calculations by using a more accurate density instead. A novel procedure employs the Hartree-Fock density to bonds that are more severely stretched than ever before. This substantially increases the range of accurate potential energy surfaces obtainable from semilocal DFT for many heteronuclear molecules. We show that this works for both neutral and charged molecules. We explain why and explore more difficult cases, for example, CH(+), where density-corrected DFT results are even better than sophisticated methods like CCSD. We give a simple criterion for when DC-DFT should be more accurate than self-consistent DFT that can be applied for most cases. PMID:26722874

  8. Potential alternative energy technologies on the Outer Continental Shelf.

    SciTech Connect

    Elcock, D.; Environmental Assessment

    2007-04-20

    This technical memorandum (TM) describes the technology requirements for three alternative energy technologies for which pilot and/or commercial projects on the U.S. Outer Continental Shelf (OCS) are likely to be proposed within the next five to seven years. For each of the alternative technologies--wind, wave, and ocean current--the TM first presents an overview. After each technology-specific overview, it describes the technology requirements for four development phases: site monitoring and testing, construction, operation, and decommissioning. For each phase, the report covers the following topics (where data are available): facility description, electricity generated, ocean area (surface and bottom) occupied, resource requirements, emissions and noise sources, hazardous materials stored or used, transportation requirements, and accident potential. Where appropriate, the TM distinguishes between pilot-scale (or demonstration-scale) facilities and commercial-scale facilities.

  9. Generation of acoustic self-bending and bottle beams by phase engineering

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Li, Tongcang; Zhu, Jie; Zhu, Xuefeng; Yang, Sui; Wang, Yuan; Yin, Xiaobo; Zhang, Xiang

    2014-07-01

    Directing acoustic waves along curved paths is critical for applications such as ultrasound imaging, surgery and acoustic cloaking. Metamaterials can direct waves by spatially varying the material properties through which the wave propagates. However, this approach is not always feasible, particularly for acoustic applications. Here we demonstrate the generation of acoustic bottle beams in homogeneous space without using metamaterials. Instead, the sound energy flows through a three-dimensional curved shell in air leaving a close-to-zero pressure region in the middle, exhibiting the capability of circumventing obstacles. By designing the initial phase, we develop a general recipe for creating self-bending wave packets, which can set acoustic beams propagating along arbitrary prescribed convex trajectories. The measured acoustic pulling force experienced by a rigid ball placed inside such a beam confirms the pressure field of the bottle. The demonstrated acoustic bottle and self-bending beams have potential applications in medical ultrasound imaging, therapeutic ultrasound, as well as acoustic levitations and isolations.

  10. Energy strategy and mitigation potential in energy sector of the Russian federation

    SciTech Connect

    Yakovlev, A.F.; Petrov, V.N.; Chupyatov, V.P.

    1996-12-31

    This paper describes the mitigation potential in the Russian energy sector and presents CO{sub 2} - emission scenarios. Based on the Russian energy strategy, energy conservation potential has been estimated and three groups of energy conservation measures have been pointed out. Taking into account the economic development scenarios and the scenarios of energy consumption and energy conservation, future CO{sub 2} emission scenarios for 2000 and 2010 have been prepared. Some important characteristics of these scenarios have been presented and discussed. For the period 2000-2010 annual growth rates for CO{sub 2} emission in the Russian energy sector will not exceed 0.9-1.3 %, and emission levels in 2000 make up - 75-78 %, and in 2010 - 81-88 % of the 1990 level. For the probable scenario the CO{sub 2} emission reducing will make up about 6% and 25% (for the optimistic scenario about 16% and 31%) of CO{sub 2} emission for reference scenario in 2000 and 2010 respectively. Additional CO{sub 2} emission reducing (3-5% of domestic CO{sub 2} emission) will result from increasing share of natural gas consumption.

  11. Bandwidth Study on Energy Use and Potential Energy Saving Opportunities in U.S. Pulp and Paper Manufacturing

    SciTech Connect

    Sabine Brueske, Caroline Kramer, Aaron Fisher

    2015-06-01

    Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. pulp and paper manufacturing. The study relies on multiple sources to estimate the energy used in six individual process areas, representing 52% of sector-wide energy consumption. Energy savings opportunities for individual processes are based on technologies currently in use or under development; the potential savings are then extrapolated to estimate sector-wide energy savings opportunity

  12. Bandwidth Study on Energy Use and Potential Energy Saving Opportunities in U.S. Iron and Steel Manufacturing

    SciTech Connect

    Keith Jamison, Caroline Kramer, Sabine Brueske, Aaron Fisher

    2015-06-01

    Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. iron and steel manufacturing. The study relies on multiple sources to estimate the energy used in six individual process areas and select subareas, representing 82% of sector-wide energy consumption. Energy savings opportunities for individual processes and subareas are based on technologies currently in use or under development; the potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

  13. Spectroscopic constants and potential energy curves of tungsten carbide

    SciTech Connect

    Balasubramanian, K.

    2000-05-01

    Spectroscopic constants (R{sub e},{omega}{sub e},T{sub e},{mu}{sub e}) and potential energy curves for 40 low-lying electronic states of the diatomic tungsten carbide (WC) were obtained using the complete active space multiconfiguration self-consistent field followed by the multireference singles+doubles configuration interaction and full first- and second-order configuration interaction calculations that included up to 6.4 mil configurations. Spin-orbit effects were included through the enhanced relativistic configuration interaction method described here for 28 electronic states of WC lying below {approx}20 000 cm-1. The spin-orbit splitting of the ground state of WC was found to be very large (4394 cm-1). The ground and excited electronic states of the W atom were also computed and were found to be in good agreement with the experimental data. The nature of bonding was analyzed through the composition of orbitals, leading configurations, Mulliken populations, and dipole moments. The dissociation energy of WC was computed including spin-orbit and electron correlation effects. The recent photoelectron spectra of WC{sup -} were assigned on the basis of our computed results. (c) 2000 American Institute of Physics.

  14. An Accurate Potential Energy Surface for H2O

    NASA Technical Reports Server (NTRS)

    Schwenke, David W.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    We have carried out extensive high quality ab initio electronic structure calculations of the ground state potential energy surface (PES) and dipole moment function (DMF) for H2O. A small adjustment is made to the PES to improve the agreement of line positions from theory and experiment. The theoretical line positions are obtained from variational ro-vibrational calculations using the exact kinetic energy operator. For the lines being fitted, the root-mean-square error was reduced from 6.9 to 0.08 /cm. We were then able to match 30,092 of the 30,117 lines from the HITRAN 96 data base to theoretical lines, and 80% of the line positions differed less than 0.1 /cm. About 3% of the line positions in the experimental data base appear to be incorrect. Theory predicts the existence of many additional weak lines with intensities above the cutoff used in the data base. To obtain results of similar accuracy for HDO, a mass dependent correction to the PH is introduced and is parameterized by simultaneously fitting line positions for HDO and D2O. The mass dependent PH has good predictive value for T2O and HTO. Nonadiabatic effects are not explicitly included. Line strengths for vibrational bands summed over rotational levels usually agree well between theory and experiment, but individual line strengths can differ greatly. A high temperature line list containing about 380 million lines has been generated using the present PES and DMF

  15. Global potential energy hypersurface for dynamical studies of energy transfer in HF--HF collisions

    SciTech Connect

    Redmon, M.J.; Binkley, J.S.

    1987-07-15

    The interaction energy of two HF molecules at 1332 individual points has been calculated with Moeller--Plesset (many--body) perturbation theory at the MP4-SDTQ level using a 6-311G** basis set. 293 of the points correspond to stretching of one HF molecule from its equilibrium geometry. No attempt was made to use a sufficiently fine grid to accurately describe the well region corresponding to hydrogen bonding. However, the location and minimum energy are consistent with experiment and other accurate theoretical results. An extensive global fit (rms error of 1 kcal/mol) is reported of 1319 points (below 10 eV of potential energy) using a modified London potential with corrections obtained using polynomials through four-body interactions. A model electrostatic potential represents the long-range interaction. In addition, the use of an expansion in products of three Legendre functions is discussed. It is shown that the latter approach, although accurately fitting the ab initio data, has difficulties interpolating in regions of the surface exhibiting diverse magnitudes of potential energy, and therefore must be used with caution. This surface should be useful for studies of T--V--R processes in this system.

  16. Wind and Solar Energy Potential Assessment for Development of Renewables Energies Applications in Bucaramanga, Colombia

    NASA Astrophysics Data System (ADS)

    Ordóñez, G.; Osma, G.; Vergara, P.; Rey, J.

    2014-06-01

    Currently, the trend of micro-grids and small-scale renewable generation systems implementation in urban environments requires to have historical and detailed information about the energy potential resource in site. In Colombia, this information is limited and do not favor the design of these applications; for this reason, must be made detailed studies of the energy potential in their cities. In this paper is presented the wind and solar energy resource assessment for the city of Bucaramanga, based on the monitoring on four strategic points during the years 2010, 2011 and 2012. According to the analysis, is evidenced a significant solar resource throughout the year ascending on average to 1 734 kWh/m2, equivalent to 4.8 kWh/m2/day. Also, from a wind statistical study based on the Weibull probability distribution and Wind Power Density (WPD) was established the wind potential as Class 1 according to the scale of the Department of Energy of the United States (DOE), since the average speed is near 1.4 m/s. Due this, it is technically unfeasible the using of micro-turbines in the city, even so their potential for natural ventilation of building was analyzed. Finally, is presented a methodology to analyze solar harvesting by sectors in the city, according to the solar motion and shadowing caused by existing structures.

  17. Tissue differentiation using laser-induced shock waves by detection of acoustic transients through an optical wave-guide

    NASA Astrophysics Data System (ADS)

    Tschepe, Johannes; Ahrens, Thomas; Helfmann, Juergen; Mueller, Gerhard J.; Gapontsev, Valentin P.

    1993-05-01

    Some physical phenomena which occur during the fragmentation of calculi by laser induced optical break down are presented. With in vitro experiments it could be shown that the energy of the laser induced plasma and of the cavitation bubble (induced by the plasma) depends by the nature of the tissue. The laser induced plasma and the cavitation bubble generate shock waves. These sound waves are transferred via the laser fiber and detected with a piezo- electrical sensor at the proximal end. The acoustic signal contains information on the potential energy of the bubble, which depends on the energy of the plasma. The possibility of measuring the energy dependent acoustic transients allows to distinguish between hard and soft tissue and by this it is suitable for controlling the laser lithotripsy process. The transmission of acoustic transients through silica glass fibers is investigated by theoretical calculations. It shows the feasibility of silica glass fibers as an acoustic wave guide.

  18. Material and energy recovery in integrated waste management systems: the potential for energy recovery.

    PubMed

    Consonni, Stefano; Viganò, Federico

    2011-01-01

    This article is part of a set of six coordinated papers reporting the main findings of a research project carried out by five Italian universities on "Material and energy recovery in Integrated Waste Management Systems (IWMS)". An overview of the project and a summary of the most relevant results can be found in the introductory article of the series. This paper describes the work related to the evaluation of mass and energy balances, which has consisted of three major efforts (i) development of a model for quantifying the energy content and the elemental compositions of the waste streams appearing in a IWMS; (ii) upgrade of an earlier model to predict the performances of Waste-to-Energy (WtE) plants; (iii) evaluation of mass and energy balances of all the scenarios and the recovery paths considered in the project. Results show that not only the amount of material available for energy recovery is significantly higher than the Unsorted Residual Waste (URW) left after Separate Collection (SC), because selection and recycling generate significant amounts of residues, but its heating value is higher than that of the original, gross waste. Therefore, the energy potential of what is left after recycling is always higher than the complement to 100% of the Source Separation Level (SSL). Also, increasing SSL has marginal effects on the potential for energy recovery: nearly doubling SSL (from 35% to 65%) reduces the energy potential only by one fourth. Consequently, even at high SSL energy recovery is a fundamental step of a sustainable waste management system. Variations of SSL do bring about variations of the composition, heating value and moisture content of the material fed to WtE plants, but these variations (i) are smaller than one can expect; (ii) have marginal effects on the performances of the WtE plant. These considerations suggest that the mere value of SSL is not a good indicator of the quality of the waste management system, nor of its energy and environmental

  19. 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.

  20. 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.

  1. Single mode acoustic fiber waveguide

    NASA Technical Reports Server (NTRS)

    Jackson, B. S.; May, R. G.; Claus, R. O.

    1984-01-01

    The single mode operation of a clad rod acoustic waveguide is described. Unlike conventional clad optical and acoustic waveguiding structures which use modes confined to a central core surrounded by a cladding, this guide supports neither core nor cladding modes but a single interface wave field on the core-cladding boundary. The propagation of this bound field and the potential improved freedom from spurious responses is discussed.

  2. Acoustically assisted spin-transfer-torque switching of nanomagnets: An energy-efficient hybrid writing scheme for non-volatile memory

    SciTech Connect

    Biswas, Ayan K.; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha

    2013-12-02

    We show that the energy dissipated to write bits in spin-transfer-torque random access memory can be reduced by an order of magnitude if a surface acoustic wave (SAW) is launched underneath the magneto-tunneling junctions (MTJs) storing the bits. The SAW-generated strain rotates the magnetization of every MTJs' soft magnet from the easy towards the hard axis, whereupon passage of a small spin-polarized current through a target MTJ selectively switches it to the desired state with > 99.99% probability at room temperature, thereby writing the bit. The other MTJs return to their original states at the completion of the SAW cycle.

  3. 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

  4. Transportation Energy Futures Series. Potential for Energy Efficiency Improvement Beyond the Light-Duty-Vehicle Sector

    SciTech Connect

    Vyas, A. D.; Patel, D. M.; Bertram, K. M.

    2013-02-01

    Considerable research has focused on energy efficiency and fuel substitution options for light-duty vehicles, while much less attention has been given to medium- and heavy-duty trucks, buses, aircraft, marine vessels, trains, pipeline, and off-road equipment. This report brings together the salient findings from an extensive review of literature on future energy efficiency options for these non-light-duty modes. Projected activity increases to 2050 are combined with forecasts of overall fuel efficiency improvement potential to estimate the future total petroleum and greenhouse gas (GHG) emissions relative to current levels. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.

  5. Transportation Energy Futures Series: Potential for Energy Efficiency Improvement Beyond the Light-Duty-Vehicle Sector

    SciTech Connect

    Vyas, A. D.; Patel, D. M.; Bertram, K. M.

    2013-03-01

    Considerable research has focused on energy efficiency and fuel substitution options for light-duty vehicles, while much less attention has been given to medium- and heavy-duty trucks, buses, aircraft, marine vessels, trains, pipeline, and off-road equipment. This report brings together the salient findings from an extensive review of literature on future energy efficiency options for these non-light-duty modes. Projected activity increases to 2050 are combined with forecasts of overall fuel efficiency improvement potential to estimate the future total petroleum and greenhouse gas (GHG) emissions relative to current levels. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.

  6. IRETHERM: The geothermal energy potential of Irish radiothermal granites

    NASA Astrophysics Data System (ADS)

    Farrell, Thomas; Jones, Alan; Muller, Mark; Feely, Martin; Brock, Andrew; Long, Mike; Waters, Tim

    2014-05-01

    The IRETHERM project is developing a strategic understanding of Ireland's deep geothermal energy potential through integrated modelling of new and existing geophysical and geological data. One aspect of IRETHERM's research focuses on Ireland's radiothermal granites, where increased concentrations of radioelements provide elevated heat-production (HP), surface heat-flow (SHF) and subsurface temperatures. An understanding of the contribution of granites to the thermal field of Ireland is important to assessing the geothermal energy potential of this low-enthalpy setting. This study focuses on the Galway granite in western Ireland, and the Leinster and the buried Kentstown granites in eastern Ireland. Shallow (<250 m) boreholes were drilled into the exposed Caledonian Leinster and Galway granites as part of a 1980's geothermal project. These studies yielded HP = 2-3 μWm-3 and HF = 80 mWm-2 at the Sally Gap borehole in the Northern Units of the Leinster granite, to the SW of Dublin. In the Galway granite batholith, on the west coast of Ireland, the Costelloe-Murvey granite returned HP = 7 μWm-3 and HF = 77 mWm-2, measured at the Rossaveal borehole. The buried Kentstown granite, 35 km NW of Dublin, has an associated negative Bouguer anomaly and was intersected by two mineral exploration boreholes at depths of 660 m and 490 m. Heat production is measured at 2.4 μWm-3 in core samples taken from the weathered top 30 m of the granite. The core of this study consists of a program of magnetotelluric (MT) and audio-magnetotelluric (AMT) data acquisition across the three granite bodies, over three fieldwork seasons. MT and AMT data were collected at 59 locations along two profiles over the Leinster granite. Preliminary results show that the northern units of the Leinster granite (40 km SW of Dublin) extend to depths of 2-5 km. Preliminary results from the southern profile suggest a greater thickness of granite to a depth of 6-9 km beneath the Tullow pluton, 75 km SW of

  7. Computed Potential Energy Surfaces and Minimum Energy Pathways for Chemical Reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

    1994-01-01

    Computed potential energy surfaces are often required for computation of such parameters as rate constants as a function of temperature, product branching ratios, and other detailed properties. For some dynamics methods, global potential energy surfaces are required. In this case, it is necessary to obtain the energy at a complete sampling of all the possible arrangements of the nuclei, which are energetically accessible, and then a fitting function must be obtained to interpolate between the computed points. In other cases, characterization of the stationary points and the reaction pathway connecting them is sufficient. These properties may be readily obtained using analytical derivative methods. We have found that computation of the stationary points/reaction pathways using CASSCF/derivative methods, followed by use of the internally contracted CI method to obtain accurate energetics, gives usefull results for a number of chemically important systems. The talk will focus on a number of applications including global potential energy surfaces, H + O2, H + N2, O(3p) + H2, and reaction pathways for complex reactions, including reactions leading to NO and soot formation in hydrocarbon combustion.

  8. Energy of Cohesion, Compressibility, and the Potential Energy Functions of the Graphite System

    NASA Technical Reports Server (NTRS)

    Girifalco, L. A.; Lad, R. A.

    1956-01-01

    The lattice summations of the potential energy of importance in the graphite system have been computed by direct summation assuming a Lennard-Jones 6-12 potential between carbon atoms. From these summations, potential energy curves were constructed for interactions between a carbon atom and a graphite monolayer, between a carbon atom and a graphite surface, between a graphite monolayer and a semi-infinite graphite crystal and between two graphite semi-infinite crystals. Using these curves, the equilibrium distance between two isolated physically interacting carbon atoms was found to be 2.70 a, where a is the carbon-carbon distance in a graphite sheet. The distance between a surface plane and the rest of the crystal was found to be 1.7% greater than the interlayer spacing. Theoretical values of the energy of cohesion and the compressibility were calculated from the potential curve for the interaction between two semi-infinite crystals. They were (delta)E(sub c) = -330 ergs/sq cm and beta =3.18x10(exp -12)sq cm/dyne, respectively. These compared favorably with the experimental values of (delta)E(sub c) = -260 ergs/sq cm and beta = 2.97 X 10(exp -2) sq cm/dyne.

  9. Tropical Cyclone Signatures in Atmospheric Convective Available Potential Energy

    NASA Astrophysics Data System (ADS)

    Studholme, Joshua; Gulev, Sergey

    2016-04-01

    Tropical cyclones play an important role in the climate system providing transports of energy and water vapor, forcing the ocean, and also affecting mid-latitude circulation phenomena. Tropical cyclone tracks experience strong interannual variability and in addition, longer term trend-like changes in all ocean basins. Analysis of recent historical data reveal a poleward shift in the locations of tropical cyclone tracks in both the Northern and Southern Hemispheres (Kossin et al. 2014, Nature, 509, 349-352). The physical consequences of these alterations are largely unconstrained. For example, the increasing encroachment of tropical cyclone activity into the extra-tropical environment presents a novel and still poorly understood paradigm for tropical-extratropical interactions. In this respect, the role that the atmospheric convective available potential energy (CAPE) plays in the dynamics of tropical cyclones is highly interesting. The two characteristic global-scale spatial patterns in CAPE are identified using EOF analysis. The first pattern shows an abundance of CAPE in the centre of the Pacific and corresponds to the El Nino Southern Oscillation. The second one is capturing positive CAPE anomalies in the oceanic tropics and negative anomalies over equatorial Africa. Associated with these buoyancy patterns, alterations in tropical cyclone activity occur in all basins forming both zonal and meridional patterns. Atmospheric buoyancy is the trigger for deep convection, and subsequently cyclone genesis. This is the mechanism of impact upon location at the start of cyclone tracks. It is found to have less impact upon where cyclones subsequently move, whether or not they undergo extratropical transition and when and where they experience lysis. It is shown that CAPE plays a critical role in the general circulation in the tropics which in turn is the larger steering context for embedded systems within the Walker and Hadley cells. So this lack of `latter life' impact

  10. 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.

  11. 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.}

  12. Controlling sound with acoustic metamaterials

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  13. Acoustic control in enclosures using optimally designed Helmholtz resonators

    NASA Astrophysics Data System (ADS)

    Driesch, Patricia Lynne

    A virtual design methodology is developed to minimize the noise in enclosures with optimally designed, passive, acoustic absorbers (Helmholtz resonators). A series expansion of eigen functions is used to represent the acoustic absorbers as external volume velocities, eliminating the need for a solution of large matrix eigen value problems. A determination of this type (efficient model/reevaluation approach) significantly increases the design possibilities when optimization techniques are implemented. As a benchmarking exercise, this novel methodology was experimentally validated for a narrowband acoustic assessment of two optimally designed Helmholtz resonators coupled to a 2D enclosure. The resonators were tuned to the two lowest resonance frequencies of a 30.5 by 40.6 by 2.5 cm (12 x 16 x 1 inch) cavity with the resonator volume occupying only 2% of the enclosure volume. A maximum potential energy reduction of 12.4 dB was obtained at the second resonance of the cavity. As a full-scale demonstration of the efficacy of the proposed design method, the acoustic response from 90--190 Hz of a John Deere 7000 Ten series tractor cabin was investigated. The lowest cabin mode, referred to as a "boom" mode, proposes a significant challenge to a noise control engineer since its anti-node is located near the head of the operator and often generates unacceptable sound pressure levels. Exploiting the low frequency capability of Helmholtz resonators, lumped parameter models of these resonators were coupled to the enclosure via an experimentally determined acoustic model of the tractor cabin. The virtual design methodology uses gradient optimization techniques as a post processor for the modeling and analysis of the unmodified acoustic interior to determine optimal resonator characteristics. Using two optimally designed Helmholtz resonators; potential energy was experimentally reduced by 3.4 and 10.3 dB at 117 and 167 Hz, respectively.

  14. Networks of triboelectric nanogenerators for harvesting water wave energy: a potential approach toward blue energy.

    PubMed

    Chen, Jun; Yang, Jin; Li, Zhaoling; Fan, Xing; Zi, Yunlong; Jing, Qingshen; Guo, Hengyu; Wen, Zhen; Pradel, Ken C; Niu, Simiao; Wang, Zhong Lin

    2015-03-24

    With 70% of the earth's surface covered with water, wave energy is abundant and has the potential to be one of the most environmentally benign forms of electric energy. However, owing to lack of effective technology, water wave energy harvesting is almost unexplored as an energy source. Here, we report a network design made of triboelectric nanogenerators (TENGs) for large-scale harvesting of kinetic water energy. Relying on surface charging effect between the conventional polymers and very thin layer of metal as electrodes for each TENG, the TENG networks (TENG-NW) that naturally float on the water surface convert the slow, random, and high-force oscillatory wave energy into electricity. On the basis of the measured output of a single TENG, the TENG-NW is expected to give an average power output of 1.15 MW from 1 km(2) surface area. Given the compelling features, such as being lightweight, extremely cost-effective, environmentally friendly, easily implemented, and capable of floating on the water surface, the TENG-NW renders an innovative and effective approach toward large-scale blue energy harvesting from the ocean. PMID:25719956

  15. Potential Ambient Energy-Harvesting Sources and Techniques

    ERIC Educational Resources Information Center

    Yildiz, Faruk

    2009-01-01

    Ambient energy harvesting is also known as energy scavenging or power harvesting, and it is the process where energy is obtained from the environment. A variety of techniques are available for energy scavenging, including solar and wind powers, ocean waves, piezoelectricity, thermoelectricity, and physical motions. For example, some systems…

  16. Potential energy surface of fluoroxene: experiment and theory.

    PubMed

    Uriarte, Iciar; Écija, Patricia; Spada, Lorenzo; Zabalza, Eneko; Lesarri, Alberto; Basterretxea, Francisco J; Fernández, José A; Caminati, Walther; Cocinero, Emilio J

    2016-02-01

    The potential energy surface (PES) of the general anesthetic fluoroxene (2,2,2-trifluoroethyl vinyl ether) was probed in a supersonic jet expansion using broadband chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy and theoretical calculations. The PES is dominated by a single conformation, as other stable minima are shown to kinetically relax in the expansion to the global minimum. Consistently, the rotational spectrum reveals a single conformation. Fluoroxene adopts a CS heavy-atom planar skeleton structure in the gas phase, with a cis-trans conformation (cis for the CH2=CH-O-CH2- and trans for the =CH-O-CH2-CF3 part). The sensitivity of a recently-built CP-FTMW spectrometer at the UPV/EHU is demonstrated by the detection of five isotopologues of fluoroxene in natural abundance, corresponding to the (13)C and (18)O monosubstituted species. The rS and r0 structures were determined and are in good agreement with theoretical predictions using the MP2, B3LYP and M06-2X methods. PMID:26771032

  17. Potential of utilization of geothermal energy in Arizona. Executive summary

    SciTech Connect

    White, D.H.; Goldstone, L.A.

    1982-08-01

    Arizona is one of the fastest growing states in the United States. It is in the midst of the movement of the population of the United States from its cold regions to the warm Southwest. Being a hot, arid region, its electrical demand is nearly 50% higher in the peak hot summer months than that of the other seven months. The major uncertainty of utilizing geothermal energy in Arizona is that very little exploration and development have occurred to date. The potential is good, based on (a) the fact that there are over 3000 thermal wells in Arizona out of a total of about 30,000 shallow (less than 1000 ft) irrigation wells. In addition, there is much young volcanic rock in the State of Arizona. The combination of data from thermal wells, young volcanic rock, water geochemistry and other geological tools, indicate that there is a large geothermal resource throughout the southern half of the state. It is believed that most of this resource is in the range of 50/sup 0/C (122/sup 0/F) to 150/sup 0/C (302/sup 0/F), limiting its uses to direct heat utilization rather than for electric power generation.

  18. Theoretical characterization of the potential energy surface for NH + NO

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1992-01-01

    The potential energy surface (PES) for NH + NO was characterized using complete active space self-consistent field (CASSCF) gradient calculations to determine the stationary point geometries and frequencies followed by CASSCF/internally contracted configuration interaction (CCI) calculations to refine the energetics. The present results are in qualitative accord with the BAC-MP4 calculations, but there are differences as large as 8 kcal/mol in the detailed energetics. Addition of NH to NO on a (2)A' surface, which correlated with N2 + OH or H + N2O products, involves barriers of 3.2 kcal/mol (trans) and 6.3 kcal/mol (cis). Experimental evidence for these barriers is found in earlier works. The (2)A' surface has no barrier to addition, but does not correlate with products. Surface crossings between the barrierless (2)A' surface and the (2)A' surface may be important. Production of N2 + OH products is predicted to occur via a planar saddle point of (2)A' symmetry. This is in accord with the preferential formation of II(A') lambda doublet levels of OH in earlier experiments. Addition of NH (1)delta to NO is found to occur on an excited state surface and is predicted to lead to N2O product as observed in earlier works.

  19. (Molecular understanding of mutagenicity using potential energy methods)

    SciTech Connect

    Broyde, S.

    1990-01-01

    The objective of our work has been, for many year, to elucidate on a molecular level at atomic resolution the structures of DNAs modified by highly mutagenic polycyclic aromatic amines and hydrocarbons, and their less mutagenic chemically related analogs and unmodified DNAs, as controls. The ultimate purpose of this undertaking is to obtain an understanding of the relationship DNA structures and mutagenicity. Our methods for elucidating structures are computational, but we keep in close contact with experimental developments, and have, very recently, been able to incorporate the first experimental information from NMR studies by other workers in our calculations. The specific computational methods we employ are minimized potential energy calculations using the torsion angle space program DUPLEX, developed and written by Dr. Brain Hingerty to yield static views. Molecular dynamics simulations of the important static structures with full solvation and salt are carried out with the program AMBER; this yields mobile views in a milieu that best mimics the natural environment of the cell. In addition, we have been developing new strategies for searching conformation space and building DNA duplexes from favored subunit structures. 30 refs., 12 figs.

  20. Molecular understanding of mutagenicity using potential energy methods

    SciTech Connect

    Broyde, S.; Shapiro, R.

    1992-07-01

    Our objective, has been to elucidate on a molecular level, at atomic resolution, the structures of DNAs modified by 2-aminofluorene and its N-acetyl derivative, 2-acetylaminofluorene (AAF). The underlying hypothesis is that DNA replicates with reduced fidelity when its normal right-handed B-structure is altered, and one result is a higher mutation rate. This change in structure may occur normally at a low incidence, for example by the formation of hairpin loops in appropriate sequences, but it may be enhanced greatly after covalent modification by a mutagenic substance. We use computational methods and have been able to incorporate the first data from NMR studies in our calculations. Computational approaches are important because x-ray and spectroscopic studies have not succeeded in producing atomic resolution views of mutagen and carcinogen-oligonucleotide adducts. The specific methods that we employ are minimized potential energy calculations using the torsion angle space molecular mechanics program DUPLEX to yield static views. Molecular dynamics simulations, with full solvent and salt, of the important static structures are carried out with the program AMBER; this yields mobile views in a medium that mimics the natural aqueous environment of the cell as well as can be done with current available computing resources.