WorldWideScience

Sample records for acoustic nmr

  1. Acoustics

    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.

  2. Acoustic detection of electron spin resonance

    Coufal, H.

    1981-07-01

    The ESR-signal of DPPH was recorded by detecting the modulation of the absorbed microwave power with a gas-coupled microphone. This photo-acoustic detection scheme is compared with conventional ESR-detection. Applications of the acoustical detection method to other modulation spectroscopic techniques, particularly NMR, are discussed.

  3. Compact NMR

    Bluemich, Bernhard; Haber-Pohlmeier, Sabina; Zia, Wasif [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie (ITMC)

    2014-06-01

    Nuclear Magnetic Resonance (NMR) spectroscopy is the most popular method for chemists to analyze molecular structures, while Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool for medical doctors that provides high-contrast images of biological tissue. In both applications, the sample (or patient) is positioned inside a large, superconducting magnet to magnetize the atomic nuclei. Interrogating radio-frequency pulses result in frequency spectra that provide the chemist with molecular information, the medical doctor with anatomic images, and materials scientist with NMR relaxation parameters. Recent advances in magnet technology have led to a variety of small permanent magnets to allow compact and low-cost instruments. The goal of this book is to provide an introduction to the practical use of compact NMR at a level nearly as basic as the operation of a smart phone.

  4. Compact NMR

    Nuclear Magnetic Resonance (NMR) spectroscopy is the most popular method for chemists to analyze molecular structures, while Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool for medical doctors that provides high-contrast images of biological tissue. In both applications, the sample (or patient) is positioned inside a large, superconducting magnet to magnetize the atomic nuclei. Interrogating radio-frequency pulses result in frequency spectra that provide the chemist with molecular information, the medical doctor with anatomic images, and materials scientist with NMR relaxation parameters. Recent advances in magnet technology have led to a variety of small permanent magnets to allow compact and low-cost instruments. The goal of this book is to provide an introduction to the practical use of compact NMR at a level nearly as basic as the operation of a smart phone.

  5. Communication Acoustics

    Blauert, Jens

    Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book...... the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as......: acoustics, cognitive science, speech science, and communication technology....

  6. Acoustic Neuroma

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

  7. Acoustic Neuroma

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

  8. NMR spectroscopy

    The book reviews the applications of NMR-spectroscopy in medicine and biology. The first chapter of about 40 pages summarizes the history of development and explains the chemical and physical fundamentals of this new and non-invasive method in an easily comprehensible manner. The other chapters summarize diagnostic results obtained with this method in organs and tissues, so that the reader will find a systematic overview of the available findings obtained in the various organ systems. It must be noted, however, that ongoing research work and new insight quite naturally will necessitate corrections to be done, as is the case here with some biochemical interpretations which would need adjustment to latest research results. NMR-spectroscopy is able to measure very fine energy differences on the molecular level, and thus offers insight into metabolic processes, with the advantage that there is no need of applying ionizing radiation in order to qualitatively or quantitatively analyse the metabolic processes in the various organ systems. (orig./DG) With 40 figs., 4 tabs

  9. Acoustic cloaking and transformation acoustics

    In this review, we give a brief introduction to the application of the new technique of transformation acoustics, which draws on a correspondence between coordinate transformation and material properties. The technique is formulated for both acoustic waves and linear liquid surface waves. Some interesting conceptual devices can be designed for manipulating acoustic waves. For example, we can design acoustic cloaks that make an object invisible to acoustic waves, and the cloak can either encompass or lie outside the object to be concealed. Transformation acoustics, as an analog of transformation optics, can go beyond invisibility cloaking. As an illustration for manipulating linear liquid surface waves, we show that a liquid wave rotator can be designed and fabricated to rotate the wave front. The acoustic transformation media require acoustic materials which are anisotropic and inhomogeneous. Such materials are difficult to find in nature. However, composite materials with embedded sub-wavelength resonators can in principle be made and such 'acoustic metamaterials' can exhibit nearly arbitrary values of effective density and modulus tensors to satisfy the demanding material requirements in transformation acoustics. We introduce resonant sonic materials and Helmholtz resonators as examples of acoustic metamaterials that exhibit resonant behaviour in effective density and effective modulus. (topical review)

  10. Acoustic cloaking and transformation acoustics

    Chen Huanyang [School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu 215006 (China); Chan, C T, E-mail: kenyon@ust.h, E-mail: phchan@ust.h [Department of Physics and the William Mong Institute of NanoScience and Technology, The Hong Kong University of Science and Technology, Clear Water Bay (Hong Kong)

    2010-03-24

    In this review, we give a brief introduction to the application of the new technique of transformation acoustics, which draws on a correspondence between coordinate transformation and material properties. The technique is formulated for both acoustic waves and linear liquid surface waves. Some interesting conceptual devices can be designed for manipulating acoustic waves. For example, we can design acoustic cloaks that make an object invisible to acoustic waves, and the cloak can either encompass or lie outside the object to be concealed. Transformation acoustics, as an analog of transformation optics, can go beyond invisibility cloaking. As an illustration for manipulating linear liquid surface waves, we show that a liquid wave rotator can be designed and fabricated to rotate the wave front. The acoustic transformation media require acoustic materials which are anisotropic and inhomogeneous. Such materials are difficult to find in nature. However, composite materials with embedded sub-wavelength resonators can in principle be made and such 'acoustic metamaterials' can exhibit nearly arbitrary values of effective density and modulus tensors to satisfy the demanding material requirements in transformation acoustics. We introduce resonant sonic materials and Helmholtz resonators as examples of acoustic metamaterials that exhibit resonant behaviour in effective density and effective modulus. (topical review)

  11. Acoustical Imaging

    Litniewski, Jerzy; Kujawska, Tamara; 31st International Symposium on Acoustical Imaging

    2012-01-01

    The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place continuously since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2011 the 31st International Symposium on Acoustical Imaging was held in Warsaw, Poland, April 10-13. Offering both a broad perspective on the state-of-the-art as well as  in-depth research contributions by the specialists in the field, this Volume 31 in the Series contains an excellent collection of papers in six major categories: Biological and Medical Imaging Physics and Mathematics of Acoustical Imaging Acoustic Microscopy Transducers and Arrays Nondestructive Evaluation and Industrial Applications Underwater Imaging

  12. Radiation acoustics

    Lyamshev, Leonid M

    2004-01-01

    Radiation acoustics is a developing field lying at the intersection of acoustics, high-energy physics, nuclear physics, and condensed matter physics. Radiation Acoustics is among the first books to address this promising field of study, and the first to collect all of the most significant results achieved since research in this area began in earnest in the 1970s.The book begins by reviewing the data on elementary particles, absorption of penetrating radiation in a substance, and the mechanisms of acoustic radiation excitation. The next seven chapters present a theoretical treatment of thermoradiation sound generation in condensed media under the action of modulated penetrating radiation and radiation pulses. The author explores particular features of the acoustic fields of moving thermoradiation sound sources, sound excitation by single high-energy particles, and the efficiency and optimal conditions of thermoradiation sound generation. Experimental results follow the theoretical discussions, and these clearl...

  13. NMR studies of metabolism

    In this paper, the authors present applications of NMR to the study of different aspects of metabolism. The authors begin with a brief outline of localization methods that are commonly used to obtain in vivo NMR spectra. The authors then describe in more detail metabolic information recently obtained by NMR of perfused organs, intact animals, and humans. Previous reviews have already covered the applications of NMR to the study of metabolism in microorganisms, isolated or cultivated cells, and tumors. NMR spectroscopy of the brain, and human in vivo NMR spectroscopy have also been reviewed

  14. NMR analysis of biodiesel

    Biodiesel is usually analyzed by the various methods called for in standards such as ASTM D6751 and EN 14214. Nuclear magnetic resonance (NMR) is not one of these methods. However, NMR, with 1H-NMR commonly applied, can be useful in a variety of applications related to biodiesel. These include monit...

  15. Acoustical Imaging

    Akiyama, Iwaki

    2009-01-01

    The 29th International Symposium on Acoustical Imaging was held in Shonan Village, Kanagawa, Japan, April 15-18, 2007. This interdisciplinary Symposium has been taking place every two years since 1968 and forms a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. In the course of the years the volumes in the Acoustical Imaging Series have developed and become well-known and appreciated reference works. Offering both a broad perspective on the state-of-the-art in the field as well as an in-depth look at its leading edge research, this Volume 29 in the Series contains again an excellent collection of seventy papers presented in nine major categories: Strain Imaging Biological and Medical Applications Acoustic Microscopy Non-Destructive Evaluation and Industrial Applications Components and Systems Geophysics and Underwater Imaging Physics and Mathematics Medical Image Analysis FDTD method and Other Numerical Simulations Audience Researcher...

  16. Acoustic telemetry

    National Oceanic and Atmospheric Administration, Department of Commerce — To determine movements of green turtles in the nearshore foraging areas, we deployed acoustic tags and determined their movements through active and passive...

  17. Acoustics Research

    National Oceanic and Atmospheric Administration, Department of Commerce — Fisheries acoustics data are collected from more than 200 sea-days each year aboard the FRV DELAWARE II and FRV ALBATROSS IV (decommissioned) and the FSV Henry B....

  18. Battlefield acoustics

    Damarla, Thyagaraju

    2015-01-01

    This book presents all aspects of situational awareness in a battlefield using acoustic signals. It starts by presenting the science behind understanding and interpretation of sound signals. The book then goes on to provide various signal processing techniques used in acoustics to find the direction of sound source, localize gunfire, track vehicles, and detect people. The necessary mathematical background and various classification and fusion techniques are presented. The book contains majority of the things one would need to process acoustic signals for all aspects of situational awareness in one location. The book also presents array theory, which is pivotal in finding the direction of arrival of acoustic signals. In addition, the book presents techniques to fuse the information from multiple homogeneous/heterogeneous sensors for better detection. MATLAB code is provided for majority of the real application, which is a valuable resource in not only understanding the theory but readers, can also use the code...

  19. Acoustic emission

    This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

  20. NMR at 900 MHz

    2002-01-01

    @@ An important factor in the development of solutionstate NMR has always been th e ability to produce stable and homogeneous magnetic fields. As higher and higher field strengths are reached the pressure is growing on manufacturers to produce NMR systems with greatly improved spectral resolution and signal to noise ratio. The introduction of the Varian 900 MHz INOVA system in August 2000 featuring Oxford Instruments 21.1 T magnet represents the latest pioneering development in NMR technology.

  1. Lectures on pulsed NMR

    These lectures discuss some recent developments in pulsed NMR, emphasizing fundamental principles with selected illustrative applications. Major topics covered include multiple-quantum spectroscopy, spin decoupling, the interaction of spins with a quantized field, adiabatic rapid passage, spin temperature and statistics of cross-polarization, coherent averaging, and zero field NMR. 32 refs., 56 figs

  2. Lectures on pulsed NMR

    These lectures discuss some recent developments in pulsed NMR, emphasizing fundamental principles with selected illustrative applications. Major topics covered include multiple-quantum spectroscopy, spin decoupling, the interaction of spins with a quantized field, adiabatic rapid passage, spin temperature and statistics of cross-polarization, coherent averaging, and zero field NMR. 55 figs

  3. Acoustic lenses

    Acoustic lenses focus ultrasound to produce pencil-like beams with reduced near fields. When fitted to conventional (flat-faced) transducers, such lenses greatly improve the ability to detect and size defects. This paper describes a program developed to design acoustic lenses for use in immersion or contact inspection, using normal or angle beam mode with flat or curved targets. Lens surfaces are circular in geometry to facilitate machining. For normal beam inspection of flat plate, spherical or cylindrical lenses are used. For angle beam or curved surface inspections, a compound lens is required to correct for the extra induced aberration. Such a lens is aspherical with one radius of curvature in the plane of incidence, and a different radius of curvature in the plane perpendicular to the incident plane. The resultant beam profile (i.e., location of the acoustic focus, beam diameter, 6 dB working range) depends on the degree of focusing and the transducer used. The operating frequency and bandwidth can be affected by the instrumentation used. Theoretical and measured beam profiles are in good agreement. Various applications, from zone focusing used for defect sizing in thick plate, to line focusing for pipe weld inspection, are discussed

  4. Functional studies using NMR

    This volume is based on a series of lectures delivered at a one-day teaching symposium on functional and metabolic aspects of NMR measurements held at the Middlesex Hospital Medical School on 1st September 1985 as a part of the European Nuclear Medicine Society Congress. Currently the major emphasis in medical NMR in vivo is on its potential to image and display abnormalities in conventional radiological images, providing increased contrast between normal and abnormal tissue, improved definition of vasculature, and possibly an increased potential for differential diagnosis. Although these areas are undeniably of major importance, it is probable that NMR will continue to complement conventional measurement methods. The major potential benefits to be derived from in vivo NMR measurements are likely to arise from its use as an instrument for functional and metabolic studies in both clinical research and in the everyday management of patients. It is to this area that this volume is directed

  5. Renal transplant NMR

    The preliminary results of NMR evaluation of renal transplants (Txs) are reported including correlation with nuclear medicine (NM) and ultrasound (US). Thirteen Txs (8 cadaver (Cd), 5 living related doner (LRD) in 13 patients (6M, 7F) ranging in age from 25-47 (x 35) were evaluated by NM (32), NMR (15) and US (5). Clinical diagnoses included: rejection (8), ATN (2), infarction (1), and normal (2). Of the 8 patients with rejection (5) Cd; 3 LRD) pathologic proof was obtained in 3. An experimental 0.12 T resistive magnet (GE) was used with a partial saturation technique with repetition time (TR) of 143 and 286 msec to provide T1 weighting. T2 weighted information was obtained with a spin echo technique with echo times (TE) of 20, 40, 60 and 80 msec. The NMR appearance of normal Txs consisted of a uniform signal intensity (Tx> pelvic musculature), well-defined internal architecture with good cortical medullary differentiation and normal appearing vessels. The NMR appearance of abnormal transplants consisted of a heterogeneous or overall decrease in signal intensity (kidney muscle) with poor cortical medullary differentiation with or without a halo of decreased signal intensity. Although NMR was able to differentiate normal from abnormal, it was unable to clearly discriminate between ATN and rejection. Advantages of NMR included the ability to demonstrate regional anatomy, vasculature, post operative fluid collections and hematomas, and associated avascular necrosis of the hips

  6. Acoustic hemostasis

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

    2003-04-01

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

  7. Acoustic telemetry.

    Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.

    2003-08-01

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

  8. Acoustic Neuroma Educational Video

    Full Text Available Educational Video Home What is an AN What is an Acoustic Neuroma? Identifying an AN Symptoms Acoustic Neuroma Keywords Educational Video ... for pre- and post-treatment acoustic neuroma patients. Home What is an AN What is an Acoustic ...

  9. Use of acoustic vortices in acoustic levitation

    Cutanda Henriquez, Vicente; Santillan, Arturo Orozco; Juhl, Peter Møller

    2009-01-01

    Acoustic fields are known to exert forces on the surfaces of objects. These forces are noticeable if the sound pressure is sufficiently high. Two phenomena where acoustic forces are relevant are: i) acoustic levitation, where strong standing waves can hold small objects at certain positions...... of acoustical vortices uses an efficient numerical implementation based on the superposition of two orthogonal sound fields with a delay of 90° between them. It is shown that acoustic levitation and the use of acoustic vortices can be combined to manipulate objects in an efficient and controlled manner without......, counterbalancing their weight, and ii) acoustic vortices, spinning sound fields that can impinge angular momentum and cause rotation of objects. In this contribution, both force-creating sound fields are studied by means of numerical simulations. The Boundary Element Method is employed to this end. The simulation...

  10. Acoustic dispersive prism

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

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic ...

  11. NMR Aerosolomics: Novel NMR Method for Organic Aerosol Analysis

    Horník, Štěpán; Schwarz, Jaroslav; Sýkora, Jan

    - : -, 2015, s. 162. ISBN N. [Small Molecule NMR Conference - SMASH 2015. Baveno (IT), 20.09.2015-23.09.2015] Institutional support: RVO:67985858 Keywords : aerosol * analysis * NMR Subject RIV: CC - Organic Chemistry

  12. NMR imaging technique

    This invention provides a method that can be adapted to existing NMR tomographic scanners of producing spectra of any given point in the image of the specimen slice, the intensity distribution of a selected resonance within an area of the image of the specimen slice, or an entire NMR spectrum of the given area. The method comprises acquiring n projections of the specimen slice, where n is greater than 1. Each of the projections is then shifted by Δ f for the point (the frequency offset of the signal arising from the point, from the true chemical shift)

  13. NMR a substitute for CT

    The possibility that NMR (Nuclear Magnetic Resonance) can be a substitute for CT (Computerized Tomography), is described. NMR focus on the nuclei in the atoms of certain elements, for example hydrogen

  14. International symposium on NMR spectroscopy

    The publication consists of 32 papers and presentations from the field of NMR spectroscopy applications submitted to the International Symposium on NMR Spectroscopy held at Smolenice between 29 Sep and 3 Oct, 1980. (B.S.)

  15. Acoustic Neurinomas

    Mohammad Faraji Rad

    2011-01-01

    Full Text Available Acoustic neuromas (AN are schwann cell-derived tumors that commonly arise from the vestibular portion of the eighth cranial nerve also known as vestibular schwannoma(VS causes unilateral hearing loss, tinnitus, vertigo and unsteadiness. In many cases, the tumor size may remain unchanged for many years following diagnosis, which is typically made by MRI. In the majority of cases the tumor is small, leaving the clinician and patient with the options of either serial scanning or active treatment by gamma knife radiosurgery (GKR or microneurosurgery. Despite the vast number of published treatment reports, comparative studies are few. The predominant clinical endpoints of AN treatment include tumor control, facial nerve function and hearing preservation. Less focus has been put on symptom relief and health-related quality of life (QOL. It is uncertain if treating a small tumor leaves the patient with a better chance of obtaining relief from future hearing loss, vertigo or tinnitus than by observing it without treatment.   In this paper we review the literature for the natural course, the treatment alternatives and the results of AN. Finally, we present our experience with a management strategy applied for more than 30 years.

  16. Acoustic Spatiality

    Brandon LaBelle

    2012-06-01

    Full Text Available Experiences of listening can be appreciated as intensely relational, bringing us into contact with surrounding events, bodies and things. Given that sound propagates and expands outwardly, as a set of oscillations from a particular source, listening carries with it a sensual intensity, whereby auditory phenomena deliver intrusive and disruptive as well as soothing and assuring experiences. The physicality characteristic of sound suggests a deeply impressionistic, locational "knowledge structure" – that is, the ways in which listening affords processes of exchange, of being in the world, and from which we extend ourselves. Sound, as physical energy reflecting and absorbing into the materiality around us, and even one's self, provides a rich platform for understanding place and emplacement. Sound is always already a trace of location.Such features of auditory experience give suggestion for what I may call an acoustical paradigm – how sound sets in motion not only the material world but also the flows of the imagination, lending to forces of signification and social structure, and figuring us in relation to each other. The relationality of sound brings us into a steady web of interferences, each of which announces the promise or problematic of being somewhere.

  17. Springer Handbook of Acoustics

    Rossing, Thomas D

    2007-01-01

    Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and others. The Springer Handbook of Acoustics is an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents spanning: animal acoustics including infrasound and ultrasound, environmental noise control, music and human speech and singing, physiological and psychological acoustics, architectural acoustics, physical and engineering acoustics, signal processing, medical acoustics, and ocean acoustics. This handbook reviews the most important areas of acoustics, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest rese...

  18. Responsive acoustic surfaces

    Peters, Brady; Tamke, Martin; Nielsen, Stig Anton;

    2011-01-01

    Acoustic performance is defined by the parameter of reverberation time; however, this does not capture the acoustic experience in some types of open plan spaces. As many working and learning activities now take place in open plan spaces, it is important to be able to understand and design for the...... acoustic conditions of these spaces. This paper describes an experimental research project that studied the design processes necessary to design for sound. A responsive acoustic surface was designed, fabricated and tested. This acoustic surface was designed to create specific sonic effects. The design was...... simulated using custom integrated acoustic software and also using Odeon acoustic analysis software. The research demonstrates a method for designing space- and sound-defining surfaces, defines the concept of acoustic subspace, and suggests some new parameters for defining acoustic subspaces....

  19. NMR crystallography of polylactide

    Czernek, Jiří

    Prague : Institute of Macromolecular Chemistry AS CR, v. v. i, 2013. s. 60. ISBN 978-80-85009-77-4. [European Symposium on Polymer Spectroscopy /19./ - ESOPS19. Prague Meeting on Macromolecules /77./. 07.07.2013-11.07.2013, Prague] Institutional support: RVO:61389013 Keywords : NMR crystallography * polylactide Subject RIV: CD - Macromolecular Chemistry

  20. Soils, Pores, and NMR

    Pohlmeier, Andreas; Haber-Pohlmeier, Sabina; Haber, Agnes; Sucre, Oscar; Stingaciu, Laura; Stapf, Siegfried; Blümich, Bernhard

    2010-05-01

    Within Cluster A, Partial Project A1, the pore space exploration by means of Nuclear Magnetic Resonance (NMR) plays a central role. NMR is especially convenient since it probes directly the state and dynamics of the substance of interest: water. First, NMR is applied as relaxometry, where the degree of saturation but also the pore geometry controls the NMR signature of natural porous systems. Examples are presented where soil samples from the Selhausen, Merzenhausen (silt loams), and Kaldenkirchen (sandy loam) test sites are investigated by means of Fast Field Cycling Relaxometry at different degrees of saturation. From the change of the relaxation time distributions with decreasing water content and by comparison with conventional water retention curves we conclude that the fraction of immobile water is characterized by T1 samples (Haber-Pohlmeier et al. 2010). Third, relaxometric information forms the basis of understanding magnetic resonance imaging (MRI) results. The general difficulty of imaging in soils are the inherent fast T2 relaxation times due to i) the small pore sizes, ii) presence of paramagnetic ions in the solid matrix, and iii) diffusion in internal gradients. The last point is important, since echo times can not set shorter than about 1ms for imaging purposes. The way out is either the usage of low fields for imaging in soils or special ultra-short pulse sequences, which do not create echoes. In this presentation we will give examples on conventional imaging of macropore fluxes in soil cores (Haber-Pohlmeier et al. 2010), and the combination with relaxometric imaging, as well as the advantages and drawbacks of low-field and ultra-fast pulse imaging. Also first results on the imaging of soil columns measured by SIP in Project A3 are given. Haber-Pohlmeier, S., S. Stapf, et al. (2010). "Waterflow Monitored by Tracer Transport in Natural Porous Media Using MRI." Vadose Zone J.: submitted. Haber-Pohlmeier, S., S. Stapf, et al. (2010). "Relaxation in a

  1. Acoustic source for generating an acoustic beam

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

    2016-05-31

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

  2. Acoustic Neuroma Educational Video

    Full Text Available ... Options Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask ... Options Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask ...

  3. Acoustic Neuroma Educational Video

    Full Text Available ... ANA Staff Medical Advisory Board News ANA Annual Reports Acoustic Neuroma Legacy Society Programs & Services Join/Renew ... ANA Staff Medical Advisory Board News ANA Annual Reports Acoustic Neuroma Legacy Society Programs & Services Search ANAUSA. ...

  4. Acoustic Neuroma Educational Video

    Full Text Available ... ANA Annual Reports Acoustic Neuroma Legacy Society Programs & Services Join/Renew Ways to Give ANA Discussion Forum ... ANA Annual Reports Acoustic Neuroma Legacy Society Programs & Services Search ANAUSA.org Connect with us! Educational Video ...

  5. Cystic acoustic neuromas

    Chitkara, Naveen; Chanda, Rakesh; Yadav, S. P. S.; N.K. Sharma

    2002-01-01

    Predominantly cystic acoustic neuromas are rare and they usually present with clinical and radiological features different from their more common solid counterparts. Two cases of cystic acoustic neuromas are reported here.

  6. Atlantic Herring Acoustic Surveys

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Advanced Sampling Technologies Research Group conducts annual fisheries acoustic surveys using state-of-the-art acoustic, midwater trawling, and...

  7. Acoustic Neuroma Educational Video

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

  8. Acoustic Neuroma Educational Video

    Full Text Available ... is ANA? Mission Statement Board of Directors ANA Staff Medical Advisory Board News ANA Annual Reports Acoustic ... is ANA? Mission Statement Board of Directors ANA Staff Medical Advisory Board News ANA Annual Reports Acoustic ...

  9. Acoustic Neuroma Educational Video

    Full Text Available ... Resources Patient Surveys Related Links Clinical Trials.gov Health Care Insurance Toolkit Additional Resources ANA Public Webinars © 2016 Acoustic Neuroma Association Acoustic Neuroma Association ® • ...

  10. NMR of unfolded proteins

    Amarnath Chtterjee; Ashutosh Kumar; Jeetender Chugh; Sudha Srivastava; Neel S Bhavesh; Ramakrishna V Hosur

    2005-01-01

    In the post-genomic era, as more and more genome sequences are becoming known and hectic efforts are underway to decode the information content in them, it is becoming increasingly evident that flexibility in proteins plays a crucial role in many of the biological functions. Many proteins have intrinsic disorder either wholly or in specific regions. It appears that this disorder may be important for regulatory functions of the proteins, on the one hand, and may help in directing the folding process to reach the compact native state, on the other. Nuclear magnetic resonance (NMR) has over the last two decades emerged as the sole, most powerful technique to help characterize these disordered protein systems. In this review, we first discuss the significance of disorder in proteins and then describe the recent developments in NMR methods for their characterization. A brief description of the results obtained on several disordered proteins is presented at the end.

  11. The automatic NMR gaussmeter

    The paper describes the automatic gaussmeter operating according to the principle of nuclear magnetic resonance. There have been discussed the operating principle, the block diagram and operating parameters of the meter. It can be applied to measurements of induction in electromagnets of wide-line radio-spectrometers EPR and NMR and in calibration stands of magnetic induction values. Frequency range of an autodyne oscillator from 0,6 up to 86 MHz for protons is corresponding to the field range from 0.016 up to 2T. Applicaton of other nuclei, such as 7Li and 2D is also foreseen. The induction measurement is carried over automatically, and the NMR signal and value of measured induction are displayed on a monitor screen. (author)

  12. NMR, water and plants

    This thesis describes the application of a non-destructive pulsed proton NMR method mainly to measure water transport in the xylem vessels of plant stems and in some model systems. The results are equally well applicable to liquid flow in other biological objects than plants, e.g. flow of blood and other body fluids in human and animals. The method is based on a pulse sequence of equidistant π pulses in combination with a linear magnetic field gradient. (Auth.)

  13. ACOUSTICAL STANDARDS NEWS.

    Blaeser, Susan B; Struck, Christopher J

    2016-03-01

    American National Standards (ANSI Standards) developed by Accredited Standards Committees S1, S2, S3, S3/SC 1, and S12 in the areas of acoustics, mechanical vibration and shock, bioacoustics, animal bioacoustics, and noise, respectively, are published by the Acoustical Society of America (ASA). In addition to these standards, ASA publishes a catalog of Acoustical American National Standards. To receive a copy of the latest Standards catalog, please contact Susan B. Blaeser.Comments are welcomed on all material in Acoustical Standards News.This Acoustical Standards News section in JASA, as well as the National Catalog of Acoustical Standards and other information on the Standards Program of the Acoustical Society of America, are available via the ASA home page: http://acousticalsociety.org. PMID:27036268

  14. NMR molecular photography

    Khitrin, Anatoly K.; Ermakov, Vladimir L.; Fung, B M

    2002-01-01

    A procedure is described for storing a 2D pattern consisting of 32x32 = 1024 bits in a spin state of a molecular system and then retrieving the stored information as a stack of NMR spectra. The system used is a nematic liquid crystal, the protons of which act as spin clusters with strong intramolecular interactions. The technique used is a programmable multi-frequency irradiation with low amplitude. When it is applied to the liquid crystal, a large number of coherent long-lived 1H response si...

  15. A Methodology to Integrate Magnetic Resonance and Acoustic Measurements for Reservoir Characterization

    Parra, Jorge O.; Hackert, Chris L.; Collier, Hughbert A.; Bennett, Michael

    2002-01-29

    The objective of this project was to develop an advanced imaging method, including pore scale imaging, to integrate NMR techniques and acoustic measurements to improve predictability of the pay zone in hydrocarbon reservoirs. This is accomplished by extracting the fluid property parameters using NMR laboratory measurements and the elastic parameters of the rock matrix from acoustic measurements to create poroelastic models of different parts of the reservoir. Laboratory measurement techniques and core imaging are being linked with a balanced petrographical analysis of the core and theoretical model.

  16. AST Launch Vehicle Acoustics

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

    2015-01-01

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

  17. Vibro-acoustics

    Nilsson, Anders

    2015-01-01

    This three-volume book gives a thorough and comprehensive presentation of vibration and acoustic theories. Different from traditional textbooks which typically deal with some aspects of either acoustic or vibration problems, it is unique of this book to combine those two correlated subjects together. Moreover, it provides fundamental analysis and mathematical descriptions for several crucial phenomena of Vibro-Acoustics which are quite useful in noise reduction, including how structures are excited, energy flows from an excitation point to a sound radiating surface, and finally how a structure radiates noise to a surrounding fluid. Many measurement results included in the text make the reading interesting and informative. Problems/questions are listed at the end of each chapter and the solutions are provided. This will help the readers to understand the topics of Vibro-Acoustics more deeply. The book should be of interest to anyone interested in sound and vibration, vehicle acoustics, ship acoustics and inter...

  18. Springer handbook of acoustics

    2014-01-01

    Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and electronics. The Springer Handbook of Acoustics is also in his 2nd edition an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents. This new edition of the Handbook features over 11 revised and expanded chapters, new illustrations, and 2 new chapters covering microphone arrays  and acoustic emission.  Updated chapters contain the latest research and applications in, e.g. sound propagation in the atmosphere, nonlinear acoustics in fluids, building and concert hall acoustics, signal processing, psychoacoustics, computer music, animal bioacousics, sound intensity, modal acoustics as well as new chapters on microphone arrays an...

  19. Acoustic streaming in microchannels

    Tribler, Peter Muller

    , and experimental results for the streaming-induced drag force dominated motion of particles suspended in a water-filled microchannel supporting a transverse half-wavelength resonance. The experimental and theoretical results agree within a mean relative dierence of approximately 20%, a low deviation given state......This thesis presents studies of boundary-driven acoustic streaming in microfluidic channels, which is a steady flow of the fluid initiated by the interactions of an oscillating acoustic standing wave and the rigid walls of the microchannel. The studies present analysis of the acoustic resonance......, the acoustic streaming flow, and the forces on suspended microparticles. The work is motivated by the application of particle focusing by acoustic radiation forces in medical, environmental and food sciences. Here acoustic streaming is most often unwanted, because it limits the focusability of particles...

  20. NMR spectrometers as "magnetic tongues"

    Malmendal, Anders; Amoresano, Claudia; Trotta, Roberta;

    2011-01-01

    the analyzed samples based on their chemical composition. We were able to correlate the NMR metabolomic fingerprints recorded for canned tomato samples to the sensory descriptors bitterness, sweetness, sourness, saltiness, tomato and metal taste, redness, and density, suggesting that NMR might be a very useful...

  1. NMR in pulsed magnetic field

    Abou-Hamad, Edy

    2011-09-01

    Nuclear magnetic resonance (NMR) experiments in pulsed magnetic fields up to 30.4 T focused on 1H and 93Nb nuclei are reported. Here we discuss the advantage and limitation of pulsed field NMR and why this technique is able to become a promising research tool. © 2011 Elsevier Inc. All Rights Reserved.

  2. Shallow Water Acoustic Laboratory

    Federal Laboratory Consortium — FUNCTION: Supports experimental research where high-frequency acoustic scattering and surface vibration measurements of fluid-loaded and non-fluid-loaded structures...

  3. Handbook of Engineering Acoustics

    Möser, Michael

    2013-01-01

    This book examines the physical background of engineering acoustics, focusing on empirically obtained engineering experience as well as on measurement techniques and engineering methods for prognostics. Its goal is not only to describe the state of art of engineering acoustics but also to give practical help to engineers in order to solve acoustic problems. It deals with the origin, the transmission and the methods of the abating different kinds of air-borne and structure-borne sounds caused by various mechanisms – from traffic to machinery and flow-induced sound. In addition the modern aspects of room and building acoustics, as well as psychoacoustics and active noise control, are covered.

  4. Acoustic dispersive prism

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

    2016-01-01

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

  5. Localized Acoustic Surface Modes

    Farhat, Mohamed

    2015-08-04

    We introduce the concept of localized acoustic surface modes (ASMs). 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.

  6. Fundamentals of Protein NMR Spectroscopy

    Rule, Gordon S

    2006-01-01

    NMR spectroscopy has proven to be a powerful technique to study the structure and dynamics of biological macromolecules. Fundamentals of Protein NMR Spectroscopy is a comprehensive textbook that guides the reader from a basic understanding of the phenomenological properties of magnetic resonance to the application and interpretation of modern multi-dimensional NMR experiments on 15N/13C-labeled proteins. Beginning with elementary quantum mechanics, a set of practical rules is presented and used to describe many commonly employed multi-dimensional, multi-nuclear NMR pulse sequences. A modular analysis of NMR pulse sequence building blocks also provides a basis for understanding and developing novel pulse programs. This text not only covers topics from chemical shift assignment to protein structure refinement, as well as the analysis of protein dynamics and chemical kinetics, but also provides a practical guide to many aspects of modern spectrometer hardware, sample preparation, experimental set-up, and data pr...

  7. Structural Biology: Practical NMR Applications

    Teng, Quincy

    2005-01-01

    This textbook begins with an overview of NMR development and applications in biological systems. It describes recent developments in instrument hardware and methodology. Chapters highlight the scope and limitation of NMR methods. While detailed math and quantum mechanics dealing with NMR theory have been addressed in several well-known NMR volumes, chapter two of this volume illustrates the fundamental principles and concepts of NMR spectroscopy in a more descriptive manner. Topics such as instrument setup, data acquisition, and data processing using a variety of offline software are discussed. Chapters further discuss several routine stategies for preparing samples, especially for macromolecules and complexes. The target market for such a volume includes researchers in the field of biochemistry, chemistry, structural biology and biophysics.

  8. What Is an Acoustic Neuroma

    ... org Connect with us! What is an Acoustic Neuroma? Each heading slides to reveal information. Important Points ... Neuroma Important Points To Know About an Acoustic Neuroma An acoustic neuroma, also called a vestibular schwannoma, ...

  9. Constants of NMR spectra

    The NMR (nuclear magnetic resonance) spectroscopy is a method for studying matter. It has been developed in a lot of fields of physics, physical chemistry, chemistry and biology. It concerns both the solid state and the liquid state. The study in solution of synthesis organic molecules or of organic molecules of natural origin and of biological molecules is particularly stressed on but it is also possible to study inorganic molecules. The originality of this method is to give both data on each atoms of the studied structure, on the atoms sequence in this structure, on the conformation and on the related configurations. It allows to reveal the interactions between separate molecules too. It is also a precious tool for the analysis of molecular movements. The development of this method for the study of condensed phases is particularly studied nowadays and the data obtained are for a lot of fields as acute as those obtained at the liquid state. (O.M.)

  10. Two dimensional solid state NMR

    This thesis illustrates, by discussing some existing and newly developed 2D solid state experiments, that two-dimensional NMR of solids is a useful and important extension of NMR techniques. Chapter 1 gives an overview of spin interactions and averaging techniques important in solid state NMR. As 2D NMR is already an established technique in solutions, only the basics of two dimensional NMR are presented in chapter 2, with an emphasis on the aspects important for solid spectra. The following chapters discuss the theoretical background and applications of specific 2D solid state experiments. An application of 2D-J resolved NMR, analogous to J-resolved spectroscopy in solutions, to natural rubber is given in chapter 3. In chapter 4 the anisotropic chemical shift is mapped out against the heteronuclear dipolar interaction to obtain information about the orientation of the shielding tensor in poly-(oxymethylene). Chapter 5 concentrates on the study of super-slow molecular motions in polymers using a variant of the 2D exchange experiment developed by us. Finally chapter 6 discusses a new experiment, 2D nutation NMR, which makes it possible to study the quadrupole interaction of half-integer spins. 230 refs.; 48 figs.; 8 tabs

  11. Acoustic emission source modeling

    Hora, Petr; Červená, Olga

    2010-01-01

    Roč. 4, č. 1 (2010), s. 25-36. ISSN 1802-680X R&D Projects: GA ČR GA101/09/1630 Institutional research plan: CEZ:AV0Z20760514 Keywords : acoustic emission source * wave propagation * FEM Subject RIV: BI - Acoustics

  12. Acoustic Neuroma Educational Video

    Full Text Available ... Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself Post-treatment Post-treatment ... Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself Post-treatment Post-treatment ...

  13. Acoustic Signals and Systems

    The Handbook of Signal Processing in Acoustics will compile the techniques and applications of signal processing as they are used in the many varied areas of Acoustics. The Handbook will emphasize the interdisciplinary nature of signal processing in acoustics. Each Section of the Handbook will...... present topics on signal processing which are important in a specific area of acoustics. These will be of interest to specialists in these areas because they will be presented from their technical perspective, rather than a generic engineering approach to signal processing. Non-specialists, or specialists...... from different areas, will find the self-contained chapters accessible and will be interested in the similarities and differences between the approaches and techniques used in different areas of acoustics....

  14. Ocean acoustic hurricane classification.

    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

  15. Cochlear bionic acoustic metamaterials

    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.

  16. Computational Ocean Acoustics

    Jensen, Finn B; Porter, Michael B; Schmidt, Henrik

    2011-01-01

    Since the mid-1970s, the computer has played an increasingly pivotal role in the field of ocean acoustics. Faster and less expensive than actual ocean experiments, and capable of accommodating the full complexity of the acoustic problem, numerical models are now standard research tools in ocean laboratories. The progress made in computational ocean acoustics over the last thirty years is summed up in this authoritative and innovatively illustrated new text. Written by some of the field's pioneers, all Fellows of the Acoustical Society of America, Computational Ocean Acoustics presents the latest numerical techniques for solving the wave equation in heterogeneous fluid–solid media. The authors discuss various computational schemes in detail, emphasizing the importance of theoretical foundations that lead directly to numerical implementations for real ocean environments. To further clarify the presentation, the fundamental propagation features of the techniques are illustrated in color. Computational Ocean A...

  17. NMR for chemists and biologists

    Carbajo, Rodrigo J

    2013-01-01

    This book intends to be an easy and concise introduction to the field of nuclear magnetic resonance or NMR, which has revolutionized life sciences in the last twenty years. A significant part of the progress observed in scientific areas like Chemistry, Biology or Medicine can be ascribed to the development experienced by NMR in recent times. Many of the books currently available on NMR deal with the theoretical basis and some of its main applications, but they generally demand a strong background in Physics and Mathematics for a full understanding. This book is aimed to a wide scientific audie

  18. Annual reports on NMR spectroscopy

    Webb, Graham A; McCarthy, M J

    1995-01-01

    Over recent years, no other technique has grown to such importance as that of NMR spectroscopy. It is used in all branches of science where precise structural determination is required and where the nature of interactions and reactions in solution is being studied. Annual Reports on NMR Spectroscopy has established itself as a means for the specialist and non-specialist alike to become familiar with new applications of the technique in all branches of chemistry, including biochemistry, and pharmaceutics. This volume focuses on theoretical aspects of NMR nuclear shielding and on applications of

  19. Integrative NMR for biomolecular research.

    Lee, Woonghee; Cornilescu, Gabriel; Dashti, Hesam; Eghbalnia, Hamid R; Tonelli, Marco; Westler, William M; Butcher, Samuel E; Henzler-Wildman, Katherine A; Markley, John L

    2016-04-01

    NMR spectroscopy is a powerful technique for determining structural and functional features of biomolecules in physiological solution as well as for observing their intermolecular interactions in real-time. However, complex steps associated with its practice have made the approach daunting for non-specialists. We introduce an NMR platform that makes biomolecular NMR spectroscopy much more accessible by integrating tools, databases, web services, and video tutorials that can be launched by simple installation of NMRFAM software packages or using a cross-platform virtual machine that can be run on any standard laptop or desktop computer. The software package can be downloaded freely from the NMRFAM software download page ( http://pine.nmrfam.wisc.edu/download_packages.html ), and detailed instructions are available from the Integrative NMR Video Tutorial page ( http://pine.nmrfam.wisc.edu/integrative.html ). PMID:27023095

  20. Flat acoustic lens by acoustic grating with curled slits

    We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry–Perot resonance. - Highlights: • Expression of transmission coefficient of an acoustic grating with curled slits. • Non-dispersive and tunable effective medium parameters for the acoustic grating. • A flat acoustic focusing lens with gradient index by using the acoustic grating

  1. Optical pumping and xenon NMR

    Raftery, M.D.

    1991-11-01

    Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping [sup 129]Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the [sup 131]Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen.

  2. Optical pumping and xenon NMR

    Raftery, M.D.

    1991-11-01

    Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping {sup 129}Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the {sup 131}Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen.

  3. Optical pumping and xenon NMR

    Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping 129Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the 131Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen

  4. From Architectural Acoustics to Acoustical Architecture Using Computer Simulation

    Schmidt, Anne Marie Due; KIRKEGAARD, Poul Henning

    2005-01-01

    Architectural acoustics design has in the past been based on simple design rules. However, with a growing complexity in architectural acoustics and the emergence of room acoustic simulation programmes with considerable potential, it is now possible to subjectively analyse and evaluate acoustic properties prior to the actual construction of a building. With the right tools applied, acoustic design can become an integral part of the architectural design process. The aim of this paper is to inve...

  5. Predicting Acoustics in Class Rooms

    Christensen, Claus Lynge; Rindel, Jens Holger

    2005-01-01

    Typical class rooms have fairly simple geometries, even so room acoustics in this type of room is difficult to predict using today's room acoustic computer modeling software. The reasons why acoustics of class rooms are harder to predict than acoustics of complicated concert halls might be...

  6. Underwater Applications of Acoustical Holography

    P. C. Mehta

    1984-01-01

    Full Text Available The paper describes the basic technique of acoustical holography. Requirements for recording the acoustical hologram are discussed with its ability for underwater imaging in view. Some practical systems for short-range and medium-range imaging are described. The advantages of acoustical holography over optical imaging, acoustical imaging and sonars are outlined.

  7. Tunable acoustic metamaterials

    Babaee, Sahab; Viard, Nicolas; Fang, Nicholas; Bertoldi, Katia

    2015-03-01

    We report a new class of active and switchable acoustic metamaterials composed of three-dimensional stretchable chiral helices arranged on a two-dimensional square lattice. We investigate the propagation of sounds through the proposed structure both numerically and experimentally and find that the deformation of the helices can be exploited as a novel and effective approach to control the propagation of acoustic waves. The proposed concept expands the ability of existing acoustic metamaterials since we demonstrate that the deformation can be exploited to turn on or off the band gap, opening avenues for the design of adaptive noise-cancelling devices.

  8. Phononic crystals and acoustic metamaterials

    Ming-Hui Lu; Liang Feng; Yan-Feng Chen

    2009-01-01

    Phononic crystals have been proposed about two decades ago and some important characteristics such as acoustic band structure and negative refraction have stimulated fundamental and practical studies in acoustic materials and devices since then. To carefully engineer a phononic crystal in an acoustic “atom” scale, acoustic metamaterials with their inherent deep subwavelength nature have triggered more exciting investigations on negative bulk modulus and/or negative mass density. Acoustic surf...

  9. Thermal Acoustic Fatigue Apparatus

    Federal Laboratory Consortium — The Thermal Acoustic Fatigue Apparatus (TAFA) is a progressive wave tube test facility that is used to test structures for dynamic response and sonic fatigue due to...

  10. Acoustic integrated extinction

    Norris, Andrew N

    2015-01-01

    The integrated extinction (IE) is defined as the integral of the scattering cross-section as a function of wavelength. Sohl et al. [1] derived an IE expression for acoustic scattering that is causal, i.e. the scattered wavefront in the forward direction arrives later than the incident plane wave in the background medium. The IE formula was based on electromagnetic results, for which scattering is causal by default. Here we derive a formula for the acoustic IE that is valid for causal and non-causal scattering. The general result is expressed as an integral of the time dependent forward scattering function. The IE reduces to a finite integral for scatterers with zero long-wavelength monopole and dipole amplitudes. Implications for acoustic cloaking are discussed and a new metric is proposed for broadband acoustic transparency.

  11. Acoustics Noise Test Cell

    Federal Laboratory Consortium — The Acoustic Noise Test Cell at the NASA/Caltech Jet Propulsion Laboratory (JPL) is located adjacent to the large vibration system; both are located in a class 10K...

  12. Principles of musical acoustics

    Hartmann, William M

    2013-01-01

    Principles of Musical Acoustics focuses on the basic principles in the science and technology of music. Musical examples and specific musical instruments demonstrate the principles. The book begins with a study of vibrations and waves, in that order. These topics constitute the basic physical properties of sound, one of two pillars supporting the science of musical acoustics. The second pillar is the human element, the physiological and psychological aspects of acoustical science. The perceptual topics include loudness, pitch, tone color, and localization of sound. With these two pillars in place, it is possible to go in a variety of directions. The book treats in turn, the topics of room acoustics, audio both analog and digital, broadcasting, and speech. It ends with chapters on the traditional musical instruments, organized by family. The mathematical level of this book assumes that the reader is familiar with elementary algebra. Trigonometric functions, logarithms and powers also appear in the book, but co...

  13. Compact acoustic refrigerator

    Bennett, Gloria A.

    1992-01-01

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

  14. Acoustics lecturing in Mexico

    Beristain, Sergio

    2002-11-01

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

  15. Acoustic Igniter Project

    National Aeronautics and Space Administration — An acoustic igniter eliminates the need to use electrical energy to drive spark systems to initiate combustion in liquid-propellant rockets. It does not involve the...

  16. Acoustic Neuroma Educational Video

    Full Text Available ... treatment Summary Types Of Post-treatment Issues Resources Medical Resources Considerations When Selecting a Healthcare Professional Healthcare ... ANA? Mission Statement Board of Directors ANA Staff Medical Advisory Board News ANA Annual Reports Acoustic Neuroma ...

  17. Acoustic coherent perfect absorbers

    In this paper, we explore the possibility of achieving acoustic coherent perfect absorbers. Through numerical simulations in two dimensions, we demonstrate that the energy of coherent acoustic waves can be totally absorbed by a fluid absorber with specific complex mass density or bulk modulus. The robustness of such absorbing systems is investigated under small perturbations of the absorber parameters. We find that when the resonance order is the lowest and the size of the absorber is comparable to the wavelength in the background, the phenomenon of perfect absorption is most stable. When the wavelength inside both the background and the absorber is much larger than the size of the absorber, perfect absorption is possible when the mass density of the absorber approaches the negative value of the background mass density. Finally, we show that by using suitable dispersive acoustic metamaterials, broadband acoustic perfect absorption may be achieved. (papers)

  18. Ocean acoustic reverberation tomography.

    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., 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

  19. Autonomous Acoustic Receiver System

    Federal Laboratory Consortium — FUNCTION: Collects underwater acoustic data and oceanographic data. Data are recorded onboard an ocean buoy and can be telemetered to a remote ship or shore station...

  20. Medical applications of NMR imaging and NMR spectroscopy with stable isotopes. Summary

    The current status of NMR imaging and NMR spectroscopy are summarized. For the most part examples from the March 1983 Puerto Rico symposium are used to illustrate the utility of NMR in medicine. 18 refs., 5 figs

  1. Anal acoustic reflectometry

    Mitchell, Peter J; Klarskov, Niels; Telford, Karen J; Hosker, Gordon L; Lose, Gunnar; Kiff, Edward S

    2011-01-01

    Anal acoustic reflectometry is a new technique of assessing anal sphincter function. Five new variables reflecting anal canal function are measured: the opening and closing pressure, the opening and closing elastance, and hysteresis.......Anal acoustic reflectometry is a new technique of assessing anal sphincter function. Five new variables reflecting anal canal function are measured: the opening and closing pressure, the opening and closing elastance, and hysteresis....

  2. The autonomous acoustic buoy

    Pellicer, Francisco; Reitsma, Robert; Agüera, Joaquín; Marinas, Alexandra

    2013-01-01

    The Acoustic Buoy is a project between the Laboratory of Applied Bioacoustics (LAB) and the Universitat Politècnica de Catalunya (UPC). In areas that the human activities produce high noise levels, such as oil exploration or construction, there is a need to monitor the environment for the presence of cetaceans. Another need is for fishing, to prevent endangered species from being killed. This can be done with an Autonomous Acoustic Buoy (AAB). Mooring or anchoring at to the seaflo...

  3. Acoustic emission source modeling

    Hora, Petr; Červená, Olga

    Plzeň : University of West Bohemia, 2009 - (Adámek, V.; Zajíček, M.). s. 1-2 ISBN 978-80-7043-824-4. [Výpočtová mechanika 2009. 09.11.2009-11.11.2009, Nečtiny] R&D Projects: GA ČR GA101/09/1630 Institutional research plan: CEZ:AV0Z20760514 Keywords : acoustic emission source * wave propagation * FEM Subject RIV: BI - Acoustics

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

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

    2014-01-01

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

  5. NMR Dynamic Studies in Living Systems

    闫永彬; 范明杰; 罗雪春; 张日清

    2002-01-01

    Nuclear magnetic resonance (NMR) can noninvasively monitor the intracellular concentrations and kinetic properties of numerous inorganic and organic compounds. These characteristics have made NMR a useful tool for dynamic studies of living systems. Applications of NMR to living systems have successfully extended to many areas, including studies of metabolic regulation, ion transport, and intracellular reaction rates in vivo. The major purpose of this review is to summarize the results that can be obtained by modern NMR techniques in living systems. With the advances of new techniques, NMR measurements of various nuclides have been performed for specific physiological purposes. Although some technical problems still remain and there are still discrepancies between NMR and traditional biochemical results, the abundant and unique information obtained from NMR spectra suggests that NMR will be more extensively applied in future studies of living systems. The fast development of these new techniques is providing many new NMR applications in living systems, as well as in structural biology.

  6. Acoustic vector sensor signal processing

    SUN Guiqing; LI Qihu; ZHANG Bin

    2006-01-01

    Acoustic vector sensor simultaneously, colocately and directly measures orthogonal components of particle velocity as well as pressure at single point in acoustic field so that is possible to improve performance of traditional underwater acoustic measurement devices or detection systems and extends new ideas for solving practical underwater acoustic engineering problems. Although acoustic vector sensor history of appearing in underwater acoustic area is no long, but with huge and potential military demands, acoustic vector sensor has strong development trend in last decade, it is evolving into a one of important underwater acoustic technology. Under this background, we try to review recent progress in study on acoustic vector sensor signal processing, such as signal detection, DOA estimation, beamforming, and so on.

  7. Acoustic comfort in eating establishments

    Svensson, David; Jeong, Cheol-Ho; Brunskog, Jonas

    2014-01-01

    The subjective concept of acoustic comfort in eating establishments has been investigated in this study. The goal was to develop a predictive model for the acoustic comfort, by means of simple objective parameters, while also examining which other subjective acoustic parameters could help explain...... the feeling of acoustic comfort. Through several layers of anal ysis, acoustic comfort was found to be rather complex, and could not be explained entirely by common subjective parameters such as annoyance, intelligibility or privacy. A predictive model for the mean acoustic comfort for an eating...

  8. Phononic crystals and acoustic metamaterials

    Ming-Hui Lu

    2009-12-01

    Full Text Available Phononic crystals have been proposed about two decades ago and some important characteristics such as acoustic band structure and negative refraction have stimulated fundamental and practical studies in acoustic materials and devices since then. To carefully engineer a phononic crystal in an acoustic “atom” scale, acoustic metamaterials with their inherent deep subwavelength nature have triggered more exciting investigations on negative bulk modulus and/or negative mass density. Acoustic surface evanescent waves have also been recognized to play key roles to reach acoustic subwavelength imaging and enhanced transmission.

  9. Two-dimensional NMR spectrometry

    This article is the second in a two-part series. In part one (ANALYTICAL CHEMISTRY, May 15) the authors discussed one-dimensional nuclear magnetic resonance (NMR) spectra and some relatively advanced nuclear spin gymnastics experiments that provide a capability for selective sensitivity enhancements. In this article and overview and some applications of two-dimensional NMR experiments are presented. These powerful experiments are important complements to the one-dimensional experiments. As in the more sophisticated one-dimensional experiments, the two-dimensional experiments involve three distinct time periods: a preparation period, t0; an evolution period, t1; and a detection period, t2

  10. NMR and dynamics of biopolymers

    Several basic experimental analytical NMR techniques that are frequently used for the qualitative and quantitative analysis of dynamic and exchange processes, focusing on proteins systems, are described: chemical exchange (slow exchange, fast exchange, intermediate exchange), heteronuclear relaxation measurements (relaxation parameters, strategy of relaxation data analysis, experimental results and examples, motional model interpretation of relaxation data, homonuclear relaxation); slow large-scale exchange and hydrogen-deuterium exchange are also studied: mechanisms of hydrogen exchange in a native protein, methods for measuring amide exchange rates by NMR, interpretation of amide exchange rates. 9 fig., 3 tab., 56 ref

  11. Advanced NMR characterization of zeolite catalysts

    Welsh, L. B.

    1985-04-01

    The program discussed in this report is a two-year two-phase joint UOP-University of Illinois study of the application of improved high resolution solid state nuclear magnetic resonance (NMR) techniques to the characterization of zeolite catalysts. During the first phase of this program very pure, and in some cases isotopically enriched faujasites will be prepared and studied by magic angle sample spinning NMR (MASS NMR) and variable engine sample spinning NMR (VASS NMR) on 500 and 360 MHz (proton frequency) NMR spectrometers. The NMR techniques that will be emphasized are the measurement and analysis of the (17)O NMR properties, (27)Al NMR intensity quantitation, and (27)Al and (29)Si NMR relaxation rates. During the second phase of this program these NMR techniques will be used to study the effects of impurity concentration, dealumination treatments and cation exchange on the NMR properties of faujasites. The initial emphasis of this program during Phase I is on the preparation and measurement of the NMR properties of (17)O enriched Na-Y faujasties.

  12. From Architectural Acoustics to Acoustical Architecture Using Computer Simulation

    Schmidt, Anne Marie Due; Kirkegaard, Poul Henning

    2005-01-01

    Architectural acoustics design has in the past been based on simple design rules. However, with a growing complexity in architectural acoustics and the emergence of room acoustic simulation programmes with considerable potential, it is now possible to subjectively analyse and evaluate acoustic...... properties prior to the actual construction of a building. With the right tools applied, acoustic design can become an integral part of the architectural design process. The aim of this paper is to investigate the field of application that an acoustic simulation programme can have during an architectural...... the first phases in the architectural process and set out a reverse strategy for simulation programmes to do so - from developing acoustics from given spaces to developing spaces from given acoustics...

  13. Radiofrequency and magnet technology in medical NMR

    Nuclear magnetic resonance (NMR) is briefly described, particularly its rf and magnet aspects. Particular attention is given to the duplexer, the rf coils, and new kinds of magnets for remote sensing NMR

  14. Push-through Direction Injectin NMR Automation

    Nuclear magnetic resonance (NMR) and mass spectrometry (MS) are the two major spectroscopic techniques successfully used in metabolomics studies. The non-invasive, quantitative and reproducible characteristics make NMR spectroscopy an excellent technique for detection of endogeno...

  15. Wavefront Modulation and Subwavelength Diffractive Acoustics with an Acoustic Metasurface

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

    2014-01-01

    Metasurfaces are a family of novel wavefront shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality as their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a desig...

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

    DOELLE, LESLIE L.

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

  17. Acoustic detection of pneumothorax

    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 (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 (ppneumothorax states (pPneumothorax 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 (pPneumothorax 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.

  18. Seamount acoustic scattering

    Boehlert, George W.

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

  19. Acoustics waves and oscillations

    Sen, S.N.

    2013-01-01

    Parameters of acoustics presented in a logical and lucid style Physical principles discussed with mathematical formulations Importance of ultrasonic waves highlighted Dispersion of ultrasonic waves in viscous liquids explained This book presents the theory of waves and oscillations and various applications of acoustics in a logical and simple form. The physical principles have been explained with necessary mathematical formulation and supported by experimental layout wherever possible. Incorporating the classical view point all aspects of acoustic waves and oscillations have been discussed together with detailed elaboration of modern technological applications of sound. A separate chapter on ultrasonics emphasizes the importance of this branch of science in fundamental and applied research. In this edition a new chapter ''Hypersonic Velocity in Viscous Liquids as revealed from Brillouin Spectra'' has been added. The book is expected to present to its readers a comprehensive presentation of the subject matter...

  20. Practical acoustic emission testing

    2016-01-01

    This book is intended for non-destructive testing (NDT) technicians who want to learn practical acoustic emission testing based on level 1 of ISO 9712 (Non-destructive testing – Qualification and certification of personnel) criteria. The essential aspects of ISO/DIS 18436-6 (Condition monitoring and diagnostics of machines – Requirements for training and certification of personnel, Part 6: Acoustic Emission) are explained, and readers can deepen their understanding with the help of practice exercises. This work presents the guiding principles of acoustic emission measurement, signal processing, algorithms for source location, measurement devices, applicability of testing methods, and measurement cases to support not only researchers in this field but also and especially NDT technicians.

  1. High resolution NMR theory and chemical applications

    Becker, Edwin D

    1969-01-01

    High Resolution NMR: Theory and Chemical Applications focuses on the applications of nuclear magnetic resonance (NMR), as well as chemical shifts, lattices, and couplings. The book first offers information on the theory of NMR, including nuclear spin and magnetic moment, spin lattice relaxation, line widths, saturation, quantum mechanical description of NMR, and ringing. The text then ponders on instrumentation and techniques and chemical shifts. Discussions focus on the origin of chemical shifts, reference compounds, empirical correlations of chemical shifts, modulation and phase detection,

  2. Cancer metastasis detected by NMR

    A narrow NMR line originating from the plasma membrane of a cancer cell is unexpected. The behaviour of these lines is explained in terms of fundamental physics and chemistry. There is biochemical evidence to support the presence of neutral lipid domains in the plasma membrane. T2 relaxation and clinical implications are briefly discussed

  3. A Century of Acoustic Metrology

    Rasmussen, Knud

    The development in acoustic measurement technique over the last century is reviewed with special emphasis on the metrological aspect.......The development in acoustic measurement technique over the last century is reviewed with special emphasis on the metrological aspect....

  4. A New Wave of Acoustics.

    Beyer, Robert

    1981-01-01

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

  5. Advanced Active Acoustics Lab (AAAL)

    Federal Laboratory Consortium — The Advanced Active Acoustics Lab (AAAL) is a state-of-the-art Undersea Warfare (USW) acoustic data analysis facility capable of both active and passive underwater...

  6. Densitometry By Acoustic Levitation

    Trinh, Eugene H.

    1989-01-01

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

  7. Acoustic black holes

    Visser, M

    1999-01-01

    Acoustic propagation in a moving fluid provides a conceptually clean and powerful analogy for understanding black hole physics. As a teaching tool, the analogy is useful for introducing students to both General Relativity and fluid mechanics. As a research tool, the analogy helps clarify what aspects of the physics are kinematics and what aspects are dynamics. In particular, Hawking radiation is a purely kinematical effect, whereas black hole entropy is intrinsically dynamical. Finally, I discuss the fact that with present technology acoustic Hawking radiation is almost experimentally testable.

  8. Strong acoustic wave action

    Gokhberg, M. B.

    1983-07-01

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

  9. Structural Acoustics and Vibrations

    Chaigne, Antoine

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

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

    Cheng, Ying; Liu, XiaoJun, E-mail: liuxiaojun@nju.edu.cn [Key Laboratory of Modern Acoustics, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190 (China); Zhou, Chen; Wei, Qi; Wu, DaJian [Key Laboratory of Modern Acoustics, Nanjing University, Nanjing 210093 (China)

    2013-11-25

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

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

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

  12. COMBUSTION ACOUSTICS DIAGNOSTICS

    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...

  13. Acoustic Signals and Systems

    present topics on signal processing which are important in a specific area of acoustics. These will be of interest to specialists in these areas because they will be presented from their technical perspective, rather than a generic engineering approach to signal processing. Non-specialists, or specialists...

  14. Underwater Acoustic Networking Techniques

    Otnes, Roald; Casari, Paolo; Goetz, Michael; Husøy, Thor; Nissen, Ivor; Rimstad, Knut; van Walree, Paul; Zorzi, Michele

    2012-01-01

    This literature study presents an overview of underwater acoustic networking. It provides a background and describes the state of the art of all networking facets that are relevant for underwater applications. This report serves both as an introduction to the subject and as a summary of existing protocols, providing support and inspiration for the development of network architectures.

  15. Measurement of deformations by NMR

    Bytchenkoff, Dimitri; Rodts, Stéphane

    2015-12-01

    Two NMR data acquisition protocols together with corresponding data processing algorithms for locating macroscopic objects, measuring distances between them or monitoring their displacements or deformations with microscopic precision are presented and discussed. The performance of the methods is demonstrated by applying them to the measurement of deformations of a freely supported beam under loading. We believe that our methods will find their applications in mechanics, civil engineering and medicine.

  16. NMR Studies of Inclusion Compounds

    Nikkhou Aski, Sahar

    2008-01-01

    This thesis presents the application of some of the NMR methods in studying host-guest complexes, mainly in solution. The general focus of the work is on investigating the reorientational dynamics of some small molecules that are bound inside cavities of larger moieties. In the current work, these moieties belong to two groups: cryptophanes and cyclodextrins. Depending on the structure of the cavities, properties of the guest molecules and the formed complexes vary. Chloroform and dichloromet...

  17. NMR-Based Milk Metabolomics

    Hanne C. Bertram

    2013-04-01

    Full Text Available Milk is a key component in infant nutrition worldwide and, in the Western parts of the world, also in adult nutrition. Milk of bovine origin is both consumed fresh and processed into a variety of dairy products including cheese, fermented milk products, and infant formula. The nutritional quality and processing capabilities of bovine milk is closely associated to milk composition. Metabolomics is ideal in the study of the low-molecular-weight compounds in milk, and this review focuses on the recent nuclear magnetic resonance (NMR-based metabolomics trends in milk research, including applications linking the milk metabolite profiling with nutritional aspects, and applications which aim to link the milk metabolite profile to various technological qualities of milk. The metabolite profiling studies encompass the identification of novel metabolites, which potentially can be used as biomarkers or as bioactive compounds. Furthermore, metabolomics applications elucidating how the differential regulated genes affects milk composition are also reported. This review will highlight the recent advances in NMR-based metabolomics on milk, as well as give a brief summary of when NMR spectroscopy can be useful for gaining a better understanding of how milk composition is linked to nutritional or quality traits.

  18. NMR-Based Milk Metabolomics.

    Sundekilde, Ulrik K; Larsen, Lotte B; Bertram, Hanne C

    2013-01-01

    Milk is a key component in infant nutrition worldwide and, in the Western parts of the world, also in adult nutrition. Milk of bovine origin is both consumed fresh and processed into a variety of dairy products including cheese, fermented milk products, and infant formula. The nutritional quality and processing capabilities of bovine milk is closely associated to milk composition. Metabolomics is ideal in the study of the low-molecular-weight compounds in milk, and this review focuses on the recent nuclear magnetic resonance (NMR)-based metabolomics trends in milk research, including applications linking the milk metabolite profiling with nutritional aspects, and applications which aim to link the milk metabolite profile to various technological qualities of milk. The metabolite profiling studies encompass the identification of novel metabolites, which potentially can be used as biomarkers or as bioactive compounds. Furthermore, metabolomics applications elucidating how the differential regulated genes affects milk composition are also reported. This review will highlight the recent advances in NMR-based metabolomics on milk, as well as give a brief summary of when NMR spectroscopy can be useful for gaining a better understanding of how milk composition is linked to nutritional or quality traits. PMID:24957988

  19. RECENT PROGRESS IN BIOMOLECULAR NMR

    2002-01-01

    @@ Structural genomics and proteomics were born from the understanding that functions of a protein are dictated by its 3D structure and dynamics. To understand protein functions on a genomic scale, we must know protein structures on a genomic scale. High resolution NMR can be used for this purpose. Traditional multidimensional NMR structure determination protocols become ineffective for structural genomics since to obtain a structure of a small protein of 15kD requires many months of painstaking spectral analysis and modeling. Recent advances in magnet and probe technology and in experimental methods have expanded the range of proteins amenable to structure determination and make the large scale structure determination possible. These advances are (1) effective expression systems for protein production, (2) introduction of cryoprobe, (3) structure determination with the use of the minimal amount of structural restraints obtained from the chemical shifts, residual dipolar couplings, NOEs, and computer modeling. In this talk,Iwill briefly outline these developments and related works done in our NMR lab.

  20. Structural proteomics by NMR spectroscopy.

    Shin, Joon; Lee, Woonghee; Lee, Weontae

    2008-08-01

    Structural proteomics is one of the powerful research areas in the postgenomic era, elucidating structure-function relationships of uncharacterized gene products based on the 3D protein structure. It proposes biochemical and cellular functions of unannotated proteins and thereby identifies potential drug design and protein engineering targets. Recently, a number of pioneering groups in structural proteomics research have achieved proof of structural proteomic theory by predicting the 3D structures of hypothetical proteins that successfully identified the biological functions of those proteins. The pioneering groups made use of a number of techniques, including NMR spectroscopy, which has been applied successfully to structural proteomics studies over the past 10 years. In addition, advances in hardware design, data acquisition methods, sample preparation and automation of data analysis have been developed and successfully applied to high-throughput structure determination techniques. These efforts ensure that NMR spectroscopy will become an important methodology for performing structural proteomics research on a genomic scale. NMR-based structural proteomics together with x-ray crystallography will provide a comprehensive structural database to predict the basic biological functions of hypothetical proteins identified by the genome projects. PMID:18761469

  1. Flat acoustic lens by acoustic grating with curled slits

    Peng, Pai

    2014-10-01

    We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry-Perot resonance.

  2. Acoustic classification of dwellings

    Berardi, Umberto; Rasmussen, Birgit

    2014-01-01

    Schemes for the classification of dwellings according to different building performances have been proposed in the last years worldwide. The general idea behind these schemes relates to the positive impact a higher label, and thus a better performance, should have. In particular, focusing on sound...... insulation performance, national schemes for sound classification of dwellings have been developed in several European countries. These schemes define acoustic classes according to different levels of sound insulation. Due to the lack of coordination among countries, a significant diversity in terms of...... descriptors, number of classes, and class intervals occurred between national schemes. However, a proposal “acoustic classification scheme for dwellings” has been developed recently in the European COST Action TU0901 with 32 member countries. This proposal has been accepted as an ISO work item. This paper...

  3. Acoustic methodology review

    Schlegel, R. G.

    1982-01-01

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

  4. Acoustic Tractor Beam

    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.

  5. Acoustics Discipline Overview

    Envia, Edmane; Thomas, Russell

    2007-01-01

    As part of the Fundamental Aeronautics Program Annual Review, a summary of the progress made in 2007 in acoustics research under the Subsonic Fixed Wing project is given. The presentation describes highlights from in-house and external activities including partnerships and NRA-funded research with industry and academia. Brief progress reports from all acoustics Phase 1 NRAs are also included as are outlines of the planned activities for 2008 and all Phase 2 NRAs. N+1 and N+2 technology paths outlined for Subsonic Fixed Wing noise targets. NRA Round 1 progressing with focus on prediction method advancement. NRA Round 2 initiating work focused on N+2 technology, prediction methods, and validation. Excellent partnerships in progress supporting N+1 technology targets and providing key data sets.

  6. The acoustics of snoring.

    Pevernagie, Dirk; Aarts, Ronald M; De Meyer, Micheline

    2010-04-01

    Snoring is a prevalent disorder affecting 20-40% of the general population. The mechanism of snoring is vibration of anatomical structures in the pharyngeal airway. Flutter of the soft palate accounts for the harsh aspect of the snoring sound. Natural or drug-induced sleep is required for its appearance. Snoring is subject to many influences such as body position, sleep stage, route of breathing and the presence or absence of sleep-disordered breathing. Its presentation may be variable within or between nights. While snoring is generally perceived as a social nuisance, rating of its noisiness is subjective and, therefore, inconsistent. Objective assessment of snoring is important to evaluate the effect of treatment interventions. Moreover, snoring carries information relating to the site and degree of obstruction of the upper airway. If evidence for monolevel snoring at the site of the soft palate is provided, the patient may benefit from palatal surgery. These considerations have inspired researchers to scrutinize the acoustic characteristics of snoring events. Similarly to speech, snoring is produced in the vocal tract. Because of this analogy, existing techniques for speech analysis have been applied to evaluate snoring sounds. It appears that the pitch of the snoring sound is in the low-frequency range (noise-like', and has scattered energy content in the higher spectral sub-bands (>500 Hz). To evaluate acoustic properties of snoring, sleep nasendoscopy is often performed. Recent evidence suggests that the acoustic quality of snoring is markedly different in drug-induced sleep as compared with natural sleep. Most often, palatal surgery alters sound characteristics of snoring, but is no cure for this disorder. It is uncertain whether the perceived improvement after palatal surgery, as judged by the bed partner, is due to an altered sound spectrum. Whether some acoustic aspects of snoring, such as changes in pitch, have predictive value for the presence of

  7. Acoustic emission source modeling

    Hora P.

    2010-07-01

    Full Text Available The paper deals with the acoustic emission (AE source modeling by means of FEM system COMSOL Multiphysics. The following types of sources are used: the spatially concentrated force and the double forces (dipole. The pulse excitation is studied in both cases. As a material is used steel. The computed displacements are compared with the exact analytical solution of point sources under consideration.

  8. Acoustically enhanced heat transport

    Ang, Kar M.; Hung, Yew Mun; Tan, Ming K., E-mail: tan.ming.kwang@monash.edu [School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor (Malaysia); Yeo, Leslie Y. [Micro/Nanophysics Research Laboratory, RMIT University, Melbourne, VIC 3001 (Australia); Friend, James R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093 (United States)

    2016-01-15

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

  9. Latest Trends in Acoustic Sensing

    Cinzia Caliendo

    2014-03-01

    Full Text Available Acoustics-based methods offer a powerful tool for sensing applications. Acoustic sensors can be applied in many fields ranging from materials characterization, structural health monitoring, acoustic imaging, defect characterization, etc., to name just a few. A proper selection of the acoustic wave frequency over a wide spectrum that extends from infrasound (<20 Hz up to ultrasound (in the GHz–band, together with a number of different propagating modes, including bulk longitudinal and shear waves, surface waves, plate modes, etc., allow acoustic tools to be successfully applied to the characterization of gaseous, solid and liquid environments. The purpose of this special issue is to provide an overview of the research trends in acoustic wave sensing through some cases that are representative of specific applications in different sensing fields.

  10. High-Frequency Seafloor Acoustics

    Jackson, Darrell R

    2007-01-01

    High-Frequency Seafloor Acoustics is the first book in a new series sponsored by the Office of Naval Research on the latest research in underwater acoustics. This exciting new title provides ready access to experimental data, theory, and models relevant to high-frequency seafloor acoustics and will be of interest to sonar engineers and researchers working in underwater acoustics. The physical characteristics of the seafloor affecting acoustic propagation and scattering are covered, including physical and geoacoustic properties and surface roughness. Current theories for acoustic propagation in sediments are presented along with corresponding models for reflection, scattering, and seafloor penetration. The main text is backed up by an extensive bibliography and technical appendices.

  11. Fundamentals of Shallow Water Acoustics

    Katsnelson, Boris; Lynch, James

    2012-01-01

    Shallow water acoustics (SWA), the study of how low and medium frequency sound propagates and scatters on the continental shelves of the world's oceans, has both technical interest and a large number of practical applications. Technically, shallow water poses an interesting medium for the study of acoustic scattering, inverse theory, and propagation physics in a complicated oceanic waveguide. Practically, shallow water acoustics has interest for geophysical exploration, marine mammal studies, and naval applications. Additionally, one notes the very interdisciplinary nature of shallow water acoustics, including acoustical physics, physical oceanography, marine geology, and marine biology. In this specialized volume, the authors, all of whom have extensive at-sea experience in U.S. and Russian research efforts, have tried to summarize the main experimental, theoretical, and computational results in shallow water acoustics, with an emphasis on providing physical insight into the topics presented.

  12. Wireless Acoustic Measurement System

    Anderson, Paul D.; Dorland, Wade D.; Jolly, Ronald L.

    2007-01-01

    A prototype wireless acoustic measurement system (WAMS) is one of two main subsystems of the Acoustic Prediction/ Measurement Tool, which comprises software, acoustic instrumentation, and electronic hardware combined to afford integrated capabilities for predicting and measuring noise emitted by rocket and jet engines. The other main subsystem is described in the article on page 8. The WAMS includes analog acoustic measurement instrumentation and analog and digital electronic circuitry combined with computer wireless local-area networking to enable (1) measurement of sound-pressure levels at multiple locations in the sound field of an engine under test and (2) recording and processing of the measurement data. At each field location, the measurements are taken by a portable unit, denoted a field station. There are ten field stations, each of which can take two channels of measurements. Each field station is equipped with two instrumentation microphones, a micro- ATX computer, a wireless network adapter, an environmental enclosure, a directional radio antenna, and a battery power supply. The environmental enclosure shields the computer from weather and from extreme acoustically induced vibrations. The power supply is based on a marine-service lead-acid storage battery that has enough capacity to support operation for as long as 10 hours. A desktop computer serves as a control server for the WAMS. The server is connected to a wireless router for communication with the field stations via a wireless local-area network that complies with wireless-network standard 802.11b of the Institute of Electrical and Electronics Engineers. The router and the wireless network adapters are controlled by use of Linux-compatible driver software. The server runs custom Linux software for synchronizing the recording of measurement data in the field stations. The software includes a module that provides an intuitive graphical user interface through which an operator at the control server

  13. Quality assessment of protein NMR structures

    Rosato A.; Montelione G.T.; Tejero R.

    2013-01-01

    Biomolecular NMR structures are now routinely used in biology, chemistry, and bioinformatics. Methods and metrics for assessing the accuracy and precision of protein NMR structures are beginning to be standardized across the biological NMR community. These include both knowledge-based assessment metrics, parameterized from the database of protein structures, and model versus data assessment metrics. On line servers are available that provide comprehensive protein structure quality assessment ...

  14. NMR INVESTIGATIONS OF HYDROGENATED AMORPHOUS SILICON

    J. Reimer

    1981-01-01

    A review is presented of the N.M.R. (Nuclear Magnetic Resonance) studies to date of hydrogenated amorphous silicon-hydrogen films. Structural features of proton N.M.R. lineshapes, dynamics of hydrogen containing defect sites, and the promise of quantitative determinations of local silicon-hydrogen bonding environments are discussed in detail. Finally, some comments are given on future directions for N.M.R. studies of hydrogenated thin films.

  15. An Inversion Recovery NMR Kinetics Experiment

    Williams, Travis J.; Kershaw, Allan D.; Li, Vincent; Wu, Xinping

    2011-01-01

    A convenient laboratory experiment is described in which NMR magnetization transfer by inversion recovery is used to measure the kinetics and thermochemistry of amide bond rotation. The experiment utilizes Varian spectrometers with the VNMRJ 2.3 software, but can be easily adapted to any NMR platform. The procedures and sample data sets in this article will enable instructors to use inversion recovery as a laboratory activity in applied NMR classes and provide research students with a conveni...

  16. Magneto-photo-acoustic imaging

    Qu, Min; Mallidi, Srivalleesha; Mehrmohammadi, Mohammad; Truby, Ryan; Homan, Kimberly; Joshi, Pratixa; Chen, Yun-Sheng; Sokolov, Konstantin; Emelianov, Stanislav

    2011-01-01

    Magneto-photo-acoustic imaging, a technique based on the synergy of magneto-motive ultrasound, photoacoustic and ultrasound imaging, is introduced. Hybrid nanoconstructs, liposomes encapsulating gold nanorods and iron oxide nanoparticles, were used as a dual-contrast agent for magneto-photo-acoustic imaging. Tissue-mimicking phantom and macrophage cells embedded in ex vivo porcine tissue were used to demonstrate that magneto-photo-acoustic imaging is capable of visualizing the location of cel...

  17. Room acoustic auralization with Ambisonics

    Polack, Jean-Dominique; Leão Figueiredo, Fábio

    2012-01-01

    International audience During the year of 2009, the room acoustics group of the LAM (Équipe Lutheries, Acoustique, Musique de l’Institut Jean Le Rond d’Alembert - Université Pierre et Marie Curie, Paris) performed a series of acoustical measurements in music halls in Paris. The halls were chosen in regarding their importance to the historic, architectural or acoustic domains. The measured ensemble of fourteen rooms includes quite different architectural designs. The measurements were carri...

  18. Ligand-receptor Interactions by NMR Spectroscopy

    Novak. P.

    2008-04-01

    Full Text Available Today NMR spectroscopy is a method of choice for elucidation of interactions between biomolecules and the potential ligands. Knowledge on these interactions is an essential prerequisite for the rational drug design. The most important contribution of NMR to drug design a few years ago was the 3D structure determination of proteins. Besides delivering the 3D structures of the free proteins as a raw material for the modeling studies on ligand binding, NMR can directly yield valuable experimental data on the biologically important protein-ligand complexes. In addition to X-ray diffraction, NMR spectroscopy can provide information on the internal protein dynamics ordynamics of intermolecular interactions. Changes in NMR parameters allow us to detect ("SAR by NMR" and quantitatively determine binding affinities (titration, diffusion NMR experiments, etc. of potential ligands. Also, it is possible to determine the binding site and conformations of ligands, receptors and receptor-ligand complexes with the help of NMR methods such as tr-NOESY. Epitopes or functional groups responsible for binding of ligands to the receptor can be identified by employing STD or WaterLOGSY experiments. In this review are described some of the most frequent NMR methods for the characterization of the interactions between biomolecules and ligands, together with their advantages and disadvantages.

  19. NMR exposure sensitizes tumor cells to apoptosis.

    Ghibelli, L; Cerella, C; Cordisco, S; Clavarino, G; Marazzi, S; De Nicola, M; Nuccitelli, S; D'Alessio, M; Magrini, A; Bergamaschi, A; Guerrisi, V; Porfiri, L M

    2006-03-01

    NMR technology has dramatically contributed to the revolution of image diagnostic. NMR apparatuses use combinations of microwaves over a homogeneous strong (1 Tesla) static magnetic field. We had previously shown that low intensity (0.3-66 mT) static magnetic fields deeply affect apoptosis in a Ca2+ dependent fashion (Fanelli et al., 1999 FASEBJ., 13;95-102). The rationale of the present study is to examine whether exposure to the static magnetic fields of NMR can affect apoptosis induced on reporter tumor cells of haematopoietic origin. The impressive result was the strong increase (1.8-2.5 fold) of damage-induced apoptosis by NMR. This potentiation is due to cytosolic Ca2+ overload consequent to NMR-promoted Ca2+ influx, since it is prevented by intracellular (BAPTA-AM) and extracellular (EGTA) Ca2+ chelation or by inhibition of plasma membrane L-type Ca2+ channels. Three-days follow up of treated cultures shows that NMR decrease long term cell survival, thus increasing the efficiency of cytocidal treatments. Importantly, mononuclear white blood cells are not sensitised to apoptosis by NMR, showing that NMR may increase the differential cytotoxicity of antitumor drugs on tumor vs normal cells. This strong, differential potentiating effect of NMR on tumor cell apoptosis may have important implications, being in fact a possible adjuvant for antitumor therapies. PMID:16528477

  20. Spin-Exchange Pumped NMR Gyros

    Walker, Thad G

    2016-01-01

    We present the basic theory governing spin-exchange pumped NMR gyros. We review the basic physics of spin-exchange collisions and relaxation as they pertain to precision NMR. We present a simple model of operation as an NMR oscillator and use it to analyze the dynamic response and noise properties of the oscillator. We discuss the primary systematic errors (differential alkali fields, quadrupole shifts, and offset drifts) that limit the bias stability, and discuss methods to minimize them. We give with a brief overview of a practical implementation and performance of an NMR gyro built by Northrop-Grumman Corporation, and conclude with some comments about future prospects.

  1. NMR studies of isotopically labeled RNA

    Pardi, A. [Univ. of Colorado, Boulder, CO (United States)

    1994-12-01

    In summary, the ability to generate NMR quantities of {sup 15}N and {sup 13}C-labeled RNAs has led to the development of heteronuclear multi-dimensional NMR techniques for simplifying the resonance assignment and structure determination of RNAs. These methods for synthesizing isotopically labeled RNAs are only several years old, and thus there are still relatively few applications of heteronuclear multi-dimensional NMR techniques to RNA. However, given the critical role that RNAs play in cellular function, one can expect to see an increasing number of NMR structural studies of biologically active RNAs.

  2. Advance reservoir evaluation by using NMR logging

    Based on brief explanation of the measurement principle for nuclear magnetic resonance (NMR) logging, this paper illustrates the importance of NMR logging in reservoir evaluation through typical case examples. These case examples include: Reservoir characterization and productivity evaluation by using NMR logging, determination of reservoir porosity in complex lithology, identification of oil, water and gas zones under complex reservoir conditions where resistivity log data give poor indication, guiding the implementation of completion and drilling programs, etc. Excellent application results indicate that NMR logging has its special features and advantages in comparison with conventional logging techniques. It is a very practical and very promising logging technology

  3. NMR characterization of pituitary tumors

    Twelve patients (5 male, 7 female, mean age 37.9 +- 20) with pituitary tumors were extensively evaluated with NMR imaging using a 1.5K gauss resistive magnet. Saturation recovery (SR), inversion recovery (IR) and spin echo (SE) pulse sequences were used for qualitative characterization of the lesions. T/sub 1/ calculations were also performed for brain and pituitary. Tumor histology and endocrine status were correlated with NMR data. All tumors were large with suprasellar extension (6 with prolactin secretion, 6 without). Pituitary T/sub 1/'s ranged from .2 to .64, the mean T/sub 1/ being longer than that of brain (Brain = .4 +- .04; Pit = .48 +- .14). 3 patients with histological evidence of homogeneous adenomas had long T/sub 1/'s (0.58 +- .05). 3 patients with evidence of recent or old hemorhage into the pituitary had much shorter T/sub 1/'s (0.29 +- .12). There was no relationship between prolactin secretion and T/sub 1/. Qualitative T/sub 1/ and T/sub 2/ information can be obtained by using a combination of SR, IR, and SE images. Using this method in the patients, homogeneous adenomas had similar T/sub 1/'s and longer T/sub 2/'s compared to the brain, while patients with bleeds had shorter T/sub 1/'s and T/sub 2/'s. Image T/sub 1/ characteristics correlated well with the calculated T/sub 1/ values. The range of T/sub 1/ (and potentially T/sub 2/) values which occur in apparently similar lesions are most likely due to anatomical and pathophysiological variations in these lesions. It may be ultimately possible to separate different types of pathological processes based on NMR image T/sub 1/ and T/sub 2/ characteristics after careful comparative studies of NMR and histological data are completed. The combination of calculated T/sub 1/ and T/sub 2/ with image T/sub 1/ and T/sub 2/ information may also be useful in further characterization of lesions

  4. NMR investigation of Ag nanoparticles

    Son, Kwanghyo; Jang, Zeehoon

    2013-01-01

    109Ag nuclear magnetic resonance (NMR) and relaxation measurements have been performed on two powder samples of Ag nanoparticles with average sizes of 20 nm and 80 nm. The measurements have been done in an external field of 9.4 T and in the temperature range 10 K Knight shift ( K) and the nuclear spin-lattice relaxation rate (1/ T 1) are observed to be almost identical to the values reported for the bulk Ag metal, whereby the Korringa ratio R(= K 2 T 1 T/S) is found to be 2.0 for both samples in the investigated temperature range.

  5. Truck acoustic data analyzer system

    Haynes, Howard D.; Akerman, Alfred; Ayers, Curtis W.

    2006-07-04

    A passive vehicle acoustic data analyzer system having at least one microphone disposed in the acoustic field of a moving vehicle and a computer in electronic communication the microphone(s). The computer detects and measures the frequency shift in the acoustic signature emitted by the vehicle as it approaches and passes the microphone(s). The acoustic signature of a truck driving by a microphone can provide enough information to estimate the truck speed in miles-per-hour (mph), engine speed in rotations-per-minute (RPM), turbocharger speed in RPM, and vehicle weight.

  6. Combined Environment Acoustic Chamber (CEAC)

    Federal Laboratory Consortium — Purpose: The CEAC imposes combined acoustic, thermal and mechanical loads on aerospace structures. The CEAC is employed to measure structural response and determine...

  7. Acoustic transparency and slow sound using detuned acoustic resonators

    Santillan, Arturo Orozco; Bozhevolnyi, Sergey I.

    2011-01-01

    We demonstrate that the phenomenon of acoustic transparency and slowsound propagation can be realized with detuned acoustic resonators (DAR), mimicking thereby the effect of electromagnetically induced transparency (EIT) in atomic physics. Sound propagation in a pipe with a series of side...

  8. Ares I Scale Model Acoustic Test Lift-Off Acoustics

    Counter, Douglas D.; Houston, Janie D.

    2011-01-01

    The lift-off acoustic (LOA) environment is an important design factor for any launch vehicle. For the Ares I vehicle, the LOA environments were derived by scaling flight data from other launch vehicles. The Ares I LOA predicted environments are compared to the Ares I Scale Model Acoustic Test (ASMAT) preliminary results.

  9. NMR studies of oriented molecules

    Sinton, S.W.

    1981-11-01

    Deuterium and proton magnetic resonance are used in experiments on a number of compounds which either form liquid crystal mesophases themselves or are dissolved in a liquid crystal solvent. Proton multiple quantum NMR is used to simplify complicated spectra. The theory of nonselective multiple quantum NMR is briefly reviewed. Benzene dissolved in a liquid crystal are used to demonstrate several outcomes of the theory. Experimental studies include proton and deuterium single quantum (..delta..M = +-1) and proton multiple quantum spectra of several molecules which contain the biphenyl moiety. 4-Cyano-4'-n-pentyl-d/sub 11/-biphenyl (5CB-d/sub 11/) is studied as a pure compound in the nematic phase. The obtained chain order parameters and dipolar couplings agree closely with previous results. Models for the effective symmetry of the biphenyl group in 5CB-d/sub 11/ are tested against the experimental spectra. The dihedral angle, defined by the planes containing the rings of the biphenyl group, is found to be 30 +- 2/sup 0/ for 5DB-d/sub 11/. Experiments are also described for 4,4'-d/sub 2/-biphenyl, 4,4' - dibromo-biphenyl, and unsubstituted biphenyl.

  10. Acoustic Mechanical Feedthroughs

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

    2013-01-01

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

  11. Dynamic acoustic tractor beams

    Mitri, F. G.

    2015-03-01

    Pulling a sphere and vibrating it around an equilibrium position by amplitude-modulation in the near-field of a single finite circular piston transducer is theoretically demonstrated. Conditions are found where a fluid hexane sphere (with arbitrary radius) chosen as an example, centered on the axis of progressive propagating waves and submerged in non-viscous water, experiences an attractive (steady) force pulling it towards the transducer, as well as an oscillatory force forcing it to vibrate back-and-forth. Numerical predictions for the dynamic force illustrate the theory and suggest an innovative method in designing dynamic acoustical tractor beams.

  12. Dynamic acoustic tractor beams

    Mitri, F. G., E-mail: F.G.Mitri@ieee.org [Chevron, Area 52 Technology – ETC, Santa Fe, New Mexico 87508 (United States)

    2015-03-07

    Pulling a sphere and vibrating it around an equilibrium position by amplitude-modulation in the near-field of a single finite circular piston transducer is theoretically demonstrated. Conditions are found where a fluid hexane sphere (with arbitrary radius) chosen as an example, centered on the axis of progressive propagating waves and submerged in non-viscous water, experiences an attractive (steady) force pulling it towards the transducer, as well as an oscillatory force forcing it to vibrate back-and-forth. Numerical predictions for the dynamic force illustrate the theory and suggest an innovative method in designing dynamic acoustical tractor beams.

  13. Taming Acoustic Cavitation

    Rivas, David Fernandez; Enriquez, Oscar R; Versluis, Michel; Prosperetti, Andrea; Gardeniers, Han; Lohse, Detlef

    2012-01-01

    In this fluid dynamics video we show acoustic cavitation occurring from pits etched on a silicon surface. By immersing the surface in a liquid, gas pockets are entrapped in the pits which upon ultrasonic insonation, are observed to shed cavitation bubbles. Modulating the driving pressure it is possible to induce different behaviours based on the force balance that determines the interaction among bubbles and the silicon surface. This system can be used for several applications like sonochemical water treatment, cleaning of surfaces with deposited materials such as biofilms.

  14. Lecture Notes On Acoustics

    This book mentions string vibration and wave, one-dimension wave and wave equation, characteristic impedance, governing equation of string, and wave energy from string, wave equation of wave and basic physical quantity like one-dimension wave equation, sound unit, sound intensity and energy, sound movement in a surface of discontinuity with transmission loss of sound by partition, and Snell's law, radiation, scatter and diffraction and sound in closed space with Sabine's theory, sound characteristic of closed space and duct acoustics.

  15. NMR Spectroscopy and Its Value: A Primer

    Veeraraghavan, Sudha

    2008-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is widely used by chemists. Furthermore, the use of NMR spectroscopy to solve structures of macromolecules or to examine protein-ligand interactions is popular. Yet, few students entering graduate education in biological sciences have been introduced to this method or its utility. Over the last six…

  16. An Inversion Recovery NMR Kinetics Experiment

    Williams, Travis J.; Kershaw, Allan D.; Li, Vincent; Wu, Xinping

    2011-01-01

    A convenient laboratory experiment is described in which NMR magnetization transfer by inversion recovery is used to measure the kinetics and thermochemistry of amide bond rotation. The experiment utilizes Varian spectrometers with the VNMRJ 2.3 software, but can be easily adapted to any NMR platform. The procedures and sample data sets in this…

  17. A Guided Inquiry Approach to NMR Spectroscopy

    Parmentier, Laura E.; Lisensky, George C.; Spencer, Brock

    1998-04-01

    We present a novel way to introduce NMR spectroscopy into the general chemistry curriculum as part of a week-long aspirin project in our one-semester introductory course. Aspirin is synthesized by reacting salicylic acid and acetic anhydride. Purity is determined by titration and IR and NMR spectroscopy. Students compare IR and NMR spectra of their aspirin product to a series of reference spectra obtained by the class. Students are able to interpret the IR spectra of their aspirin using IR data from previous experiments. NMR is introduced by having students collect 1H NMR spectra of a series of reference compounds chosen to include some of the structural features of aspirin and compare spectra and structures of the reference compounds to develop a correlation chart for chemical shifts. This process is done in small groups using shared class data and is guided by a series of questions designed to relate the different kinds of hydrogen atoms to number and position of peaks in the NMR spectrum. Students then identify the peaks in the NMR spectrum of their aspirin product and relate percent purity by titration with spectral results and percent yield. This is an enjoyable project that combines the synthesis of a familiar material with a guided inquiry-based introduction to NMR spectroscopy.

  18. NMR spectra of phosphorus 17O esters

    By the 17O NMR method the authors investigated methyl, ethyl, isopropyl, tert-butyl, and phenyl ethylene phosphites; methyl, ethyl, and isopropyl trimethylene phosphites; and methyl, ethyl, isopropyl, and tert-butyl o-phenylene phosphites. They also determined the 13C and 31P NMR spectra of these compounds

  19. 2D NMR studies of biomolecules

    The work described in this thesis comprises two related subjects. The first part describes methods to derive high-resolution structures of proteins in solution using two-dimensional (2-D) NMR. The second part describes 2-D NMR studies on the interaction between proteins and DNA. (author). 261 refs.; 52 figs.; 23 tabs

  20. Using Cloud Storage for NMR Data Distribution

    Soulsby, David

    2012-01-01

    An approach using Google Groups as method for distributing student-acquired NMR data has been implemented. We describe how to configure NMR spectrometer software so that data is uploaded to a laboratory section specific Google Group, thereby removing bottlenecks associated with printing and processing at the spectrometer workstation. Outside of…

  1. Early history of NMR at Los Alamos

    Nuclear magnetic resonance (NMR) spectroscopy has developed into an important research tool in chemistry. More recently, NMR imaging and in vivo spectroscopy promise to produce a revolution in medicine and biochemistry. Early experiments at Los Alamos led to DOE programs involving stable isotopes of importance to biology and to medicine. These events are briefly recounted. 2 refs

  2. Digital Controller For Acoustic Levitation

    Tarver, D. Kent

    1989-01-01

    Acoustic driver digitally controls sound fields along three axes. Allows computerized acoustic levitation and manipulation of small objects for such purposes as containerless processing and nuclear-fusion power experiments. Also used for controlling motion of vibration-testing tables in three dimensions.

  3. Acoustic Metamaterials and Phononic Crystals

    2013-01-01

    This comprehensive book presents all aspects of acoustic metamaterials and phononic crystals. The emphasis is on acoustic wave propagation phenomena at interfaces such as refraction, especially unusual refractive properties and negative refraction. A thorough discussion of the mechanisms leading to such refractive phenomena includes local resonances in metamaterials and scattering in phononic crystals.

  4. Acoustic engineering and technology '90

    Acoustic monitoring, testing and diagnosis in machines, production processes and products enhance the uptimes and profitability of machinery and plants. 18 papers discuss the current state of the art of acoustic monitoring systems including integrated factory planning as well as industrial health, and noise protection. (DG)

  5. Acoustic Center or Time Origin?

    Staffeldt, Henrik

    1999-01-01

    The paper discusses the acoustic center in relation to measurements of loudspeaker polar data. Also, it presents the related concept time origin and discusses the deviation that appears between positions of the acoustic center found by wavefront based and time based measuring methods....

  6. Propagation of Ion Acoustic Perturbations

    Pécseli, Hans

    1975-01-01

    Equations describing the propagation of ion acoustic perturbations are considered, using the assumption that the electrons are Boltzman distributed and isothermal at all times. Quasi-neutrality is also considered.......Equations describing the propagation of ion acoustic perturbations are considered, using the assumption that the electrons are Boltzman distributed and isothermal at all times. Quasi-neutrality is also considered....

  7. MEMS Based Acoustic Array

    Sheplak, Mark (Inventor); Nishida, Toshikaza (Inventor); Humphreys, William M. (Inventor); Arnold, David P. (Inventor)

    2006-01-01

    Embodiments of the present invention described and shown in the specification aid drawings include a combination responsive to an acoustic wave that can be utilized as a dynamic pressure sensor. In one embodiment of the present invention, the combination has a substrate having a first surface and an opposite second surface, a microphone positioned on the first surface of the substrate and having an input and a first output and a second output, wherein the input receives a biased voltage, and the microphone generates an output signal responsive to the acoustic wave between the first output and the second output. The combination further has an amplifier positioned on the first surface of the substrate and having a first input and a second input and an output, wherein the first input of the amplifier is electrically coupled to the first output of the microphone and the second input of the amplifier is electrically coupled to the second output of the microphone for receiving the output sinual from the microphone. The amplifier is spaced from the microphone with a separation smaller than 0.5 mm.

  8. Acoustics and Hearing

    Damaske, Peter

    2008-01-01

    When one listens to music at home, one would like to have an acoustic impression close to that of being in the concert hall. Until recently this meant elaborate multi-channelled sound systems with 5 or more speakers. But head-related stereophony achieves the surround-sound effect in living rooms with only two loudspeakers. By virtue of their slight directivity as well as an electronic filter the limitations previously common to two-speaker systems can be overcome and this holds for any arbitrary two-channel recording. The book also investigates the question of how a wide and diffuse sound image can arise in concert halls and shows that the quality of concert halls decisively depends on diffuse sound images arising in the onset of reverberation. For this purpose a strong onset of reverberation is modified in an anechoic chamber by electroacoustic means. Acoustics and Hearing proposes ideas concerning signal processing in the auditory system that explain the measured results and the resultant sound effects plea...

  9. Musical acoustics demonstrations

    Hoekje, P. L.

    2003-10-01

    The ASA Musical Acoustics Demonstrations website (trial version at http://www.bw.edu/~phoekje) includes sound files, video clips, program code listings, and other material for demonstrations related to musical acoustics. Many of the sound demonstrations may be experienced either as expositions, in which the phenomena are explained before they are presented, or as experiments, in which the explanation comes after listeners have had the opportunity to draw their own conclusions. Suggestions are provided for apparatus construction and classroom experiments, as well as for building simple musical instruments. Software is recommended if it is available free and compatible with multiple personal computer operating systems. For example, Audacity (http://audacity.sourceforce.net) is a sound file editor and analyzer that can be used to visually represent sounds and manipulate them. Source files are included for the synthesized sound examples, which were created in Csound (http://csounds.com), so that interested users may create their own variations. Source code is also included for visual demonstrations created in Visual Python and Python (http://www.python.org), an efficient, high level programming language. Suggestions, criticisms, and contributions are always welcome! [Work supported by ASA and Baldwin-Wallace College.

  10. Time-reversal acoustics

    Fink, Mathias [Laboratoire Ondes et Acoustique, Ecole Superieure de Physique et de Chimie Industrielle de la Ville de Paris, Universite Denis Diderot, UMR CNRS 7587, 10 Rue Vauquelin, 75005 Paris (France)], E-mail: mathias.fink@espci.fr

    2008-10-15

    Time-reversal mirrors (TRMs) refocus an incident acoustic field to the position of the original source regardless of the complexity of the propagation medium. TRM's have now been implemented in a variety of physical scenarios from MHz ultrasonics with order centimeter aperture size to hundreds/thousands of Hz in ocean acoustics with order hundred meter aperture size. Common to this broad range of scales is a remarkable robustness exemplified by observations at all scales that the more complex the medium between the probe source and the TRM, the sharper the focus. The relation between the medium complexity and the size of the focal spot is studied in this paper. It is certainly the most exciting property of TRM compared to standard focusing devices. A TRM acts as an antenna that uses complex environments to appears wider than it is, resulting for a broadband pulse in a refocusing quality that does not depend of the TRM aperture. In this paper, we investigate the time-reversal approach in various media of increasing complexity and we discuss the link existing between time-reversal approach and local helioseismology where Green's functions can be extracted from diffusive noise.

  11. Acoustic Absorption in Porous Materials

    Kuczmarski, Maria A.; Johnston, James C.

    2011-01-01

    An understanding of both the areas of materials science and acoustics is necessary to successfully develop materials for acoustic absorption applications. This paper presents the basic knowledge and approaches for determining the acoustic performance of porous materials in a manner that will help materials researchers new to this area gain the understanding and skills necessary to make meaningful contributions to this field of study. Beginning with the basics and making as few assumptions as possible, this paper reviews relevant topics in the acoustic performance of porous materials, which are often used to make acoustic bulk absorbers, moving from the physics of sound wave interactions with porous materials to measurement techniques for flow resistivity, characteristic impedance, and wavenumber.

  12. Acoustic monitoring method and device

    The present invention provides a method of eliminating resonance noises upon acoustically monitoring the operation state of power plants and plant equipments whether they are normal or not, to improve sensitivity for detecting abnormalities. Namely, a microphone detects acoustic signals including leaking sounds and converts them into electric signals. An amplifier amplifies the electric signals to an appropriate level. A noise eliminating section eliminates resonance noises other than the leaking sounds. An abnormality judging section judges presence of abnormality based on the level of the acoustic signals of the leaking sounds. With such a constitution, a plurality of resonance noises generated also during normal plant operation are automatically eliminated. Since resonance noises as a factor of lowering the sensitivity for abnormal sound detection are not included in the acoustic signals, the sensitivity for the abnormal sound detection is improved. Accordingly, the performance of the acoustic monitoring device is improved. (I.S.)

  13. Carbon-13 NMR spectroscopy of biological systems

    Beckmann, Nicolau

    1995-01-01

    This book is intended to provide an in-depth understanding of 13C NMR as a tool in biological research. 13C NMR has provided unique information concerning complex biological systems, from proteins and nucleic acids to animals and humans. The subjects addressed include multidimensional heteronuclear techniques for structural studies of molecules in the liquid and solid states, the investigation of interactions in model membranes, the elucidation of metabolic pathwaysin vitro and in vivo on animals, and noninvasive metabolic studies performed on humans. The book is a unique mix of NMR methods and biological applications which makes it a convenient reference for those interested in research in this interdisciplinary area of physics, chemistry, biology, and medicine.Key Features* An interdisciplinary text with emphasis on both 13C NMR methodology and the relevant biological and biomedical issues* State-of-the-art 13C NMR techniques are described; Whenever possible, their advantages over other approaches are empha...

  14. Applications of NMR spectroscopy to systems biochemistry.

    Fan, Teresa W-M; Lane, Andrew N

    2016-02-01

    The past decades of advancements in NMR have made it a very powerful tool for metabolic research. Despite its limitations in sensitivity relative to mass spectrometric techniques, NMR has a number of unparalleled advantages for metabolic studies, most notably the rigor and versatility in structure elucidation, isotope-filtered selection of molecules, and analysis of positional isotopomer distributions in complex mixtures afforded by multinuclear and multidimensional experiments. In addition, NMR has the capacity for spatially selective in vivo imaging and dynamical analysis of metabolism in tissues of living organisms. In conjunction with the use of stable isotope tracers, NMR is a method of choice for exploring the dynamics and compartmentation of metabolic pathways and networks, for which our current understanding is grossly insufficient. In this review, we describe how various direct and isotope-edited 1D and 2D NMR methods can be employed to profile metabolites and their isotopomer distributions by stable isotope-resolved metabolomic (SIRM) analysis. We also highlight the importance of sample preparation methods including rapid cryoquenching, efficient extraction, and chemoselective derivatization to facilitate robust and reproducible NMR-based metabolomic analysis. We further illustrate how NMR has been applied in vitro, ex vivo, or in vivo in various stable isotope tracer-based metabolic studies, to gain systematic and novel metabolic insights in different biological systems, including human subjects. The pathway and network knowledge generated from NMR- and MS-based tracing of isotopically enriched substrates will be invaluable for directing functional analysis of other 'omics data to achieve understanding of regulation of biochemical systems, as demonstrated in a case study. Future developments in NMR technologies and reagents to enhance both detection sensitivity and resolution should further empower NMR in systems biochemical research. PMID:26952191

  15. NMR-based milk metabolomics

    Sundekilde, Ulrik; Larsen, Lotte Bach; Bertram, Hanne Christine S.

    2013-01-01

    Milk is a key component in infant nutrition worldwide and, in the Western parts of the world, also in adult nutrition. Milk of bovine origin is both consumed fresh and processed into a variety of dairy products including cheese, fermented milk products, and infant formula. The nutritional quality...... and processing capabilities of bovine milk is closely associated to milk composition. Metabolomics is ideal in the study of the low-molecular-weight compounds in milk, and this review focuses on the recent nuclear magnetic resonance (NMR)-based metabolomics trends in milk research, including...... applications linking the milk metabolite profiling with nutritional aspects, and applications which aim to link the milk metabolite profile to various technological qualities of milk. The metabolite profiling studies encompass the identification of novel metabolites, which potentially can be used as biomarkers...

  16. Controlling sound with acoustic metamaterials

    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.

  17. PORTABLE ACOUSTIC MONITORING PACKAGE (PAMP)

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

    2004-07-20

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

  18. NMR in solid ionic and nanoionics

    Full text: Nuclear Magnetic Resonance (NMR) is a spectroscopic technique which employs magnetic nuclei to study, among others, the dynamics of condensed matter at the atomic level. Thus, NMR has been and still is a successful instrument in the research field of solid electrolytes also known as solid ionics. This paper presents the typical NMR experiments performed in solid ionics together with some examples from nanoionics. The experiments to be discussed comprise: (i) measurements of the diffusion coefficient employing the pulsed-field gradient and the static fringe-field method; (ii) the experimentally related NMR imaging; (iii) double resonance experiments like spin-echo double resonance (SEDOR) and two-dimensional Fourier transform NMR (2D-FT NMR); (iv) various types of nuclear relaxation, in particular spin-lattice relaxation. The NMR techniques yield information on topics like the following: type and number of mobile atoms and defects, diffusion pathways (e.g. dimensionality restrictions), atomic jump frequencies, activation energy and activation volume of these movements, diffusion coefficient with activation energy and prefactor, correlation effects in atomic movements, space correlation factor, cooperative phenomena, symmetry of atomic sites, behavior at phase transitions. These applications will be illustrated by giving examples from crystals, glasses, and polymers. (author)

  19. Acoustic emission testing

    Grosse, Christian U

    2008-01-01

    Acoustic Emission (AE) techniques have been studied in civil engineering for a long time. The techniques are recently going to be more and more applied to practical applications and to be standardized in the codes. This is because the increase of aging structures and disastrous damages due to recent earthquakes urgently demand for maintenance and retrofit of civil structures in service for example. It results in the need for the development of advanced and effective inspection techniques. Thus, AE techniques draw a great attention to diagnostic applications and in material testing. The book covers all levels from the description of AE basics for AE beginners (level of a student) to sophisticated AE algorithms and applications to real large-scale structures as well as the observation of the cracking process in laboratory specimen to study fracture processes.

  20. Surface Acoustic Wave Devices

    Dühring, Maria Bayard

    The work of this project is concerned with the simulation of surface acoustic waves (SAW) and topology optimization of SAW devices. SAWs are elastic vibrations that propagate along a material surface and are extensively used in electromechanical filters and resonators in telecommunication. A new...... application is modulation of optical waves in waveguides. This presentation elaborates on how a SAW is generated by interdigital transducers using a 2D model of a piezoelectric, inhomogeneous material implemented in the high-level programming language Comsol Multiphysics. The SAW is send through a model of a...... output waveguide and the MZI can thus be used as an optical switch. It is explained how the mechanical model of the SAW is coupled to a model of the optical waves such that the change in effective refractive index introduced in the MZI arms by the SAW can be calculated. Results of a parameter study of...

  1. Evoked acoustic emission

    Elberling, C; Parbo, J; Johnsen, N J;

    1985-01-01

    Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only...... a minor effect on the power spectra, i.e. the maximum jumps from one spectral peak to another. Experiments with deconvolution demonstrate that the emission generating system at least at a fixed intensity can be regarded as being linear and characterized by its impulse response which is similar to...... the emission evoked by click stimuli. It is concluded that significant information is obtained by the click rather than by the tonal stimuli. The click-evoked emissions were also recorded from both ears in a consecutive series of 100 full-term and otherwise normal babies 2-4 days after birth. The...

  2. Acoustic fault injection tool (AFIT)

    Schoess, Jeffrey N.

    1999-05-01

    On September 18, 1997, Honeywell Technology Center (HTC) successfully completed a three-week flight test of its rotor acoustic monitoring system (RAMS) at Patuxent River Flight Test Center. This flight test was the culmination of an ambitious 38-month proof-of-concept effort directed at demonstrating the feasibility of detecting crack propagation in helicopter rotor components. The program was funded as part of the U.S. Navy's Air Vehicle Diagnostic Systems (AVDS) program. Reductions in Navy maintenance budgets and available personnel have dictated the need to transition from time-based to 'condition-based' maintenance. Achieving this will require new enabling diagnostic technologies. The application of acoustic emission for the early detection of helicopter rotor head dynamic component faults has proven the feasibility of the technology. The flight-test results demonstrated that stress-wave acoustic emission technology can detect signals equivalent to small fatigue cracks in rotor head components and can do so across the rotating articulated rotor head joints and in the presence of other background acoustic noise generated during flight operation. During the RAMS flight test, 12 test flights were flown from which 25 Gbyte of digital acoustic data and about 15 hours of analog flight data recorder (FDR) data were collected from the eight on-rotor acoustic sensors. The focus of this paper is to describe the CH-46 flight-test configuration and present design details about a new innovative machinery diagnostic technology called acoustic fault injection. This technology involves the injection of acoustic sound into machinery to assess health and characterize operational status. The paper will also address the development of the Acoustic Fault Injection Tool (AFIT), which was successfully demonstrated during the CH-46 flight tests.

  3. An introduction to biological NMR spectroscopy

    NMR spectroscopy is a powerful tool for biologists interested in the structure, dynamics, and interactions of biological macromolecules. This review aims at presenting in an accessible manner the requirements and limitations of this technique. As an introduction, the history of NMR will highlight how the method evolved from physics to chemistry and finally to biology over several decades. We then introduce the NMR spectral parameters used in structural biology, namely the chemical shift, the J-coupling, nuclear Overhauser effects, and residual dipolar couplings. Resonance assignment, the required step for any further NMR study, bears a resemblance to jigsaw puzzle strategy. The NMR spectral parameters are then converted into angle and distances and used as input using restrained molecular dynamics to compute a bundle of structures. When interpreting a NMR-derived structure, the biologist has to judge its quality on the basis of the statistics provided. When the 3D structure is a priori known by other means, the molecular interaction with a partner can be mapped by NMR: information on the binding interface as well as on kinetic and thermodynamic constants can be gathered. NMR is suitable to monitor, over a wide range of frequencies, protein fluctuations that play a crucial role in their biological function. In the last section of this review, intrinsically disordered proteins, which have escaped the attention of classical structural biology, are discussed in the perspective of NMR, one of the rare available techniques able to describe structural ensembles. This Tutorial is part of the International Proteomics Tutorial Programme (IPTP 16 MCP). (authors)

  4. An asymptotic model in acoustics:acoustic drift equations

    Vladimirov, Vladimir; Ilin, Konstantin

    2013-01-01

    A rigorous asymptotic procedure with the Mach number as a small parameter is used to derive the equations of mean flows which coexist and are affected by the background acoustic waves in the limit of very high Reynolds number.

  5. Acoustic metamaterial with negative density

    We fabricated a one-dimensional acoustic metamaterial with negative effective density using an array of very thin elastic membranes. We observed acoustic equivalence of the plasma oscillation at ωc=735 Hz. The metamaterial was opaque in the frequency range from 0 to 735 Hz, and was transparent above 735 Hz. We report direct observation of negative acceleration in this acoustic medium below 735 Hz. The frequency characteristics of the metamaterial have the same form as that of metals with negative permittivity. We also provide a simple theory to explain the experimental results.

  6. Noise Shielding Using Acoustic Metamaterials

    We exploit theoretically a class of rectangular cylindrical devices for noise shielding by using acoustic metamaterials. The function of noise shielding is justified by both the far-field and near-field full-wave simulations based on the finite element method. The enlargement of equivalent acoustic scattering cross sections is revealed to be the physical mechanism for this function. This work makes it possible to design a window with both noise shielding and air flow. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  7. Acoustic metamaterial with negative modulus

    We present experimental and theoretical results on an acoustic metamaterial that exhibits a negative effective modulus in a frequency range from 0 to 450 Hz. A one-dimensional acoustic metamaterial with an array of side holes on a tube was fabricated. We observed that acoustic waves above 450 Hz propagated well in this structure, but no sound below 450 Hz passed through. The frequency characteristics of the metamaterial has the same form as that of the permittivity in metals due to the plasma oscillation. We also provide a theory to explain the experimental results.

  8. Anisotropic spectra of acoustic turbulence

    We found universal anizopropic spectra of acoustic turbulence with the linear dispersion law ω(k)=ck within the framework of generalized kinetic equation which takes into account the finite time of three-wave interactions. This anisotropic spectra can assume both scale-invariant and non-scale-invariant form. The implications for the evolution of the acoustic turbulence with nonisotropic pumping are discussed. The main result of the article is that the spectra of acoustic turbulence tend to become more isotropic. (c) 2000 The American Physical Society

  9. Theoretical acoustics of underwater structures

    Skelton, EA

    1997-01-01

    This important book provides an account of the linear acoustics of basic isotropic/anisotropic structures excited by time-harmonic and transient mechanical forces and acoustic sources. Many numerical examples are given to aid physical insight and to provide benchmark computations of sound radiation and sound scattering. The theoretical methods, developed originally for naval noise control problems, should find civil application in the acoustic modelling of structures fabricated from both fibre-reinforced and isotropic materials. Such an endeavour is increasingly desirable and necessary in this

  10. Graphical programming for pulse automated NMR experiments

    We describe a software program designed to control a broadband pulse Nuclear Magnetic Resonance (NMR) spectrometer used in zero-field NMR studies of magnetic metals. The software is written in the graphical language LabVIEW. This type of programming allows modifications and the inclusion of new routines to be easily made by the non-specialist, without changing the basic structure of the program. The program corrects for differences in the gain of the two acquisition channels [U (phase) and V (quadrature)], and automatic baseline subtraction. We present examples of measurements of NMR spectra, spin-echo decay (T2), and quadrupolar oscillations, performed in magnetic intermetallic compounds. (author)

  11. NMR imaging of the brain: initial impressions

    An NMR imaging system designed and built by Thorn-EMI Ltd was installed at Hammersmith Hospital in March 1981. In the first year of operation 180 patients and 40 volunteers have had cranial examinations and initial impressions bases on this experience are presented. Patients with a wide variety of neurological diseases have been studied to provide a basis for diagnostic interpretation, to define distinctive features, and to evaluate different types of scanning sequences. NMR imaging appears to be of considerable value in neurological diagnosis and has a number of advantages over CT. The detailed evaluation of NMR imaging will require much more work but the initial results are very promising

  12. Acoustic-optic investigations of acoustic gyrotropy in crystals

    For the experimental investigation of the acoustic activity the Bragg light diffraction method on transverse acoustic waves was used in the frequency range 0.4-1.8 GHz. It is shown that the oscillation period of the intensity of the diffracted light is defined by the specific rotator power of the crystal. On the basis of experimental data the specific rotation of the polarization plane in a number of gyrotropic crystals was determined. (authors)

  13. Solid-state NMR of polymers

    Nuclear magnetic resonance (NMR) spectroscopy has emerged as one of the most important methods for the solid-state characterisation of polymers. The popularity of NMR is due to the fact that many molecular level features can be measured from the NMR spectra, including the polymer chain conformation, the morphology and the dynamics. The spectral features and relaxation times are affected by local interactions, so they provide information about the structure of polymers on a length scale (2-200 A) that is difficult to measure by other methods. In favourable cases, the NMR experiments provide a molecular-level explanation for the transitions observed by differential scanning calorimetry (DSC) and other methods, and the NMR properties can often be related to the bulk properties. Solid-state NMR has long been of interest in polymer science, and the first solid-state NMR studies of polymers were reported approximately a year after the discovery of nuclear resonance in bulk matter. It was reported in this initial study that the proton line width for natural rubber at room temperature is more like that of a mobile liquid than of a solid, but that the resonance broadens near the glass transition temperature (Tg). This was recognised as being related to a change in chain dynamics above and below the Tg. NMR methods developed rapidly after these initial observations, first for polymers in solution and, more recently, for polymers in the solid-state. Solid-state NMR studies of polymers were developed more slowly than their solution-state counterparts because solid-state NMR requires more specialised equipment. Solid-state NMR is now such an important tool that most modern spectrometers are capable of performing these studies. The interest in the NMR of solid polymers is due in part to the fact that most polymers are used in the solid state, and in many cases the NMR properties can be directly related to the macroscopic properties. Polymers have restricted mobility in solids

  14. Solid-state NMR of polymers

    Mirau, P

    2001-07-01

    Nuclear magnetic resonance (NMR) spectroscopy has emerged as one of the most important methods for the solid-state characterisation of polymers. The popularity of NMR is due to the fact that many molecular level features can be measured from the NMR spectra, including the polymer chain conformation, the morphology and the dynamics. The spectral features and relaxation times are affected by local interactions, so they provide information about the structure of polymers on a length scale (2-200 A) that is difficult to measure by other methods. In favourable cases, the NMR experiments provide a molecular-level explanation for the transitions observed by differential scanning calorimetry (DSC) and other methods, and the NMR properties can often be related to the bulk properties. Solid-state NMR has long been of interest in polymer science, and the first solid-state NMR studies of polymers were reported approximately a year after the discovery of nuclear resonance in bulk matter. It was reported in this initial study that the proton line width for natural rubber at room temperature is more like that of a mobile liquid than of a solid, but that the resonance broadens near the glass transition temperature (T{sub g}). This was recognised as being related to a change in chain dynamics above and below the T{sub g}. NMR methods developed rapidly after these initial observations, first for polymers in solution and, more recently, for polymers in the solid-state. Solid-state NMR studies of polymers were developed more slowly than their solution-state counterparts because solid-state NMR requires more specialised equipment. Solid-state NMR is now such an important tool that most modern spectrometers are capable of performing these studies. The interest in the NMR of solid polymers is due in part to the fact that most polymers are used in the solid state, and in many cases the NMR properties can be directly related to the macroscopic properties. Polymers have restricted mobility

  15. NMR data-driven structure determination using NMR-I-TASSER in the CASD-NMR experiment

    NMR-I-TASSER, an adaption of the I-TASSER algorithm combining NMR data for protein structure determination, recently joined the second round of the CASD-NMR experiment. Unlike many molecular dynamics-based methods, NMR-I-TASSER takes a molecular replacement-like approach to the problem by first threading the target through the PDB to identify structural templates which are then used for iterative NOE assignments and fragment structure assembly refinements. The employment of multiple templates allows NMR-I-TASSER to sample different topologies while convergence to a single structure is not required. Retroactive and blind tests of the CASD-NMR targets from Rounds 1 and 2 demonstrate that even without using NOE peak lists I-TASSER can generate correct structure topology with 15 of 20 targets having a TM-score above 0.5. With the addition of NOE-based distance restraints, NMR-I-TASSER significantly improved the I-TASSER models with all models having the TM-score above 0.5. The average RMSD was reduced from 5.29 to 2.14 Å in Round 1 and 3.18 to 1.71 Å in Round 2. There is no obvious difference in the modeling results with using raw and refined peak lists, indicating robustness of the pipeline to the NOE assignment errors. Overall, despite the low-resolution modeling the current NMR-I-TASSER pipeline provides a coarse-grained structure folding approach complementary to traditional molecular dynamics simulations, which can produce fast near-native frameworks for atomic-level structural refinement

  16. NMR data-driven structure determination using NMR-I-TASSER in the CASD-NMR experiment

    Jang, Richard [Huazhong University of Science and Technology, School of Software Engineering (China); Wang, Yan [Huazhong University of Science and Technology, School of Life Science and Technology (China); Xue, Zhidong, E-mail: zdxue@hust.edu.cn [Huazhong University of Science and Technology, School of Software Engineering (China); Zhang, Yang, E-mail: zhng@umich.edu [University of Michigan, Department of Computational Medicine and Bioinformatics (United States)

    2015-08-15

    NMR-I-TASSER, an adaption of the I-TASSER algorithm combining NMR data for protein structure determination, recently joined the second round of the CASD-NMR experiment. Unlike many molecular dynamics-based methods, NMR-I-TASSER takes a molecular replacement-like approach to the problem by first threading the target through the PDB to identify structural templates which are then used for iterative NOE assignments and fragment structure assembly refinements. The employment of multiple templates allows NMR-I-TASSER to sample different topologies while convergence to a single structure is not required. Retroactive and blind tests of the CASD-NMR targets from Rounds 1 and 2 demonstrate that even without using NOE peak lists I-TASSER can generate correct structure topology with 15 of 20 targets having a TM-score above 0.5. With the addition of NOE-based distance restraints, NMR-I-TASSER significantly improved the I-TASSER models with all models having the TM-score above 0.5. The average RMSD was reduced from 5.29 to 2.14 Å in Round 1 and 3.18 to 1.71 Å in Round 2. There is no obvious difference in the modeling results with using raw and refined peak lists, indicating robustness of the pipeline to the NOE assignment errors. Overall, despite the low-resolution modeling the current NMR-I-TASSER pipeline provides a coarse-grained structure folding approach complementary to traditional molecular dynamics simulations, which can produce fast near-native frameworks for atomic-level structural refinement.

  17. Effects of subsampling of passive acoustic recordings on acoustic metrics.

    Thomisch, Karolin; Boebel, Olaf; Zitterbart, Daniel P; Samaran, Flore; Van Parijs, Sofie; Van Opzeeland, Ilse

    2015-07-01

    Passive acoustic monitoring is an important tool in marine mammal studies. However, logistics and finances frequently constrain the number and servicing schedules of acoustic recorders, requiring a trade-off between deployment periods and sampling continuity, i.e., the implementation of a subsampling scheme. Optimizing such schemes to each project's specific research questions is desirable. This study investigates the impact of subsampling on the accuracy of two common metrics, acoustic presence and call rate, for different vocalization patterns (regimes) of baleen whales: (1) variable vocal activity, (2) vocalizations organized in song bouts, and (3) vocal activity with diel patterns. To this end, above metrics are compared for continuous and subsampled data subject to different sampling strategies, covering duty cycles between 50% and 2%. The results show that a reduction of the duty cycle impacts negatively on the accuracy of both acoustic presence and call rate estimates. For a given duty cycle, frequent short listening periods improve accuracy of daily acoustic presence estimates over few long listening periods. Overall, subsampling effects are most pronounced for low and/or temporally clustered vocal activity. These findings illustrate the importance of informed decisions when applying subsampling strategies to passive acoustic recordings or analyses for a given target species. PMID:26233026

  18. Hybrid optical and acoustic force based sorting

    O'Mahoney, Paul; Brodie, Graham W.; Wang, Han; Demore, Christine E. M.; Cochran, Sandy; Spalding, Gabriel C.; MacDonald, Michael P.

    2014-09-01

    We report the combined use of optical sorting and acoustic levitation to give particle sorting. Differing sizes of microparticles are sorted optically both with and without the aid of acoustic levitation, and the results compared to show that the use of acoustic trapping can increase sorting efficiency. The use of a transparent ultrasonic transducer is also shown to streamline the integration of optics and acoustics. We also demonstrate the balance of optical radiation pressure and acoustic levitation to achieve vertical sorting.

  19. Frequency Steered Acoustic Transducer Project

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project is to develop, fabricate, and characterize a novel frequency steered acoustic transducer (FSAT) for the...

  20. Frequency Steered Acoustic Transducer Project

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase II project is to fabricate, characterize, and verify performance of a new type of frequency steered acoustic...

  1. Airborne synthetic aperture acoustic imaging.

    Soumekh, M

    1997-01-01

    This paper presents a system model and inversion for airborne synthetic aperture acoustic (SAA) imaging. The system model accurately represents the intercation of the acoustic source and the target region at near range values. Moreover, the model incorporates the fact that the relative speed of the vehicle's (transmitter/receiver) with respect to the target region is comparable to the acoustic wave propagation speed. The inversion utilizes the principle of spectral decomposition of spherical phase functions to develop a wavefront reconstruction method from SAA data. Processing issues and selection of appropriate acoustic FM-CW sources are discussed. Results are provided that exhibit the superior accuracy of the proposed SAA system model and inversion over their synthetic aperture radar (SAR) counterpart in which the vehicle's speed is assumed to be much smaller than the wave propagation speed. PMID:18282912

  2. Cryogenic Acoustic Suppression Testing Project

    National Aeronautics and Space Administration — The proposed project will explore and test the feasibility and effectiveness of using a cryogenic fluid (liquid nitrogen) to facilitate acoustic suppression in a...

  3. Reverberant Acoustic Test Facility (RATF)

    Federal Laboratory Consortium — The very large Reverberant Acoustic Test Facility (RATF) at the NASA Glenn Research Center (GRC), Plum Brook Station, is currently under construction and is due to...

  4. A neutron-X-ray, NMR and calorimetric study of glassy Probucol synthesized using containerless techniques

    Weber, J.K.R., E-mail: rweber@anl.gov [Materials Development, Inc., Arlington Heights, IL 60004 (United States); Argonne National Laboratory, Argonne, IL 60439 (United States); Benmore, C.J. [Argonne National Laboratory, Argonne, IL 60439 (United States); Department of Physics, Arizona State University, AZ 85287 (United States); Tailor, A.N.; Tumber, S.K. [Materials Development, Inc., Arlington Heights, IL 60004 (United States); Neuefeind, J. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Cherry, B. [Magnetic Resonance Research Center, Arizona State University, AZ 85287 (United States); Department of Chemistry and Biochemistry, Arizona State University, AZ 85287 (United States); Yarger, J.L. [Department of Physics, Arizona State University, AZ 85287 (United States); Magnetic Resonance Research Center, Arizona State University, AZ 85287 (United States); Department of Chemistry and Biochemistry, Arizona State University, AZ 85287 (United States); Mou, Q. [Magnetic Resonance Research Center, Arizona State University, AZ 85287 (United States); Department of Chemistry and Biochemistry, Arizona State University, AZ 85287 (United States); Weber, W. [Department of Physics, Arizona State University, AZ 85287 (United States); Department of Chemistry and Biochemistry, Arizona State University, AZ 85287 (United States); Byrn, S.R. [Department of Industrial and Physical Pharmacy, Purdue University, IN 47907 (United States)

    2013-10-16

    Highlights: • Acoustic levitation was used to make phase-pure glassy forms of pharmaceutical compounds. • Neutrons, X-rays and NMR were used to characterize the glasses. • The glass comprised of slightly distorted molecules packed in a random network. • Potential for new drug synthesis routes is discussed. - Abstract: Acoustic levitation was used to trap 1–3 mm diameter drops of Probucol and other pharmaceutical materials in containerless conditions. Samples were studied in situ using X-ray diffraction and ex situ using neutron diffraction, NMR and DSC techniques. The materials were brought into non-equilibrium states by supersaturating solutions or by supercooling melts. The glass transition and crystallization temperatures of glassy Probucol were 29 ± 1 and 71 ± 1 °C respectively. The glassy form was stable with a shelf life of at least 8 months. A neutron/X-ray difference function of the glass showed that while molecular sub-groups remain rigid, many of the hydrogen correlations observed in the crystal become smeared out in the disordered material. The glass is principally comprised of slightly distorted Form I Probucol molecules with disordered packing rather than large changes in the individual molecular structure. Avoiding surface contact-induced nucleation provided access to highly non-equilibrium phases and enabled synthesis of phase-pure glasses.

  5. Interfaces in polymer nanocomposites - An NMR study

    Böhme, Ute; Scheler, Ulrich

    2016-03-01

    Nuclear Magnetic Resonance (NMR) is applied for the investigation of polymer nanocomposites. Solid-state NMR is applied to study the modification steps to compatibilize layered double hydroxides with non-polar polymers. 1H relaxation NMR gives insight on the polymer dynamics over a wide range of correlation times. For the polymer chain dynamics the transverse relaxation time T2 is most suited. In this presentation we report on two applications of T2 measurements under external mechanical stress. In a low-field system relaxation NMR studies are performed in-situ under uniaxial stress. High-temperature experiments in a Couette cell permit the investigation of the polymer dynamics in the melt under shear flow.

  6. Bayesian Peak Picking for NMR Spectra

    Cheng, Yichen

    2014-02-01

    Protein structure determination is a very important topic in structural genomics, which helps people to understand varieties of biological functions such as protein-protein interactions, protein–DNA interactions and so on. Nowadays, nuclear magnetic resonance (NMR) has often been used to determine the three-dimensional structures of protein in vivo. This study aims to automate the peak picking step, the most important and tricky step in NMR structure determination. We propose to model the NMR spectrum by a mixture of bivariate Gaussian densities and use the stochastic approximation Monte Carlo algorithm as the computational tool to solve the problem. Under the Bayesian framework, the peak picking problem is casted as a variable selection problem. The proposed method can automatically distinguish true peaks from false ones without preprocessing the data. To the best of our knowledge, this is the first effort in the literature that tackles the peak picking problem for NMR spectrum data using Bayesian method.

  7. NMR spectroscopy assists synthetic fuels research

    Cookson, D.J.; Smith, B.E.

    1983-01-01

    NMR spectroscopy has proved to be a useful and versatile technique for the study of synthetic fuels feedstocks, catalysts, process intermediates and final products. Some applications of the technique to coal and gas conversion research are illustrated and discussed.

  8. Characterization of Hydrogenated Fullerenes by NMR Spectroscopy

    Hedenström, Mattias; Wågberg, Thomas; Johnels, Dan

    NMR spectroscopy is so far the only analytical technique that has been used to get a detailed structural characterization of hydrogenated fullerenes. A substantial amount of information derived from different NMR experiments can thus be found in the literature for a number of fullerenes hydrogenated to various degrees. These studies have benefitted from the fact that chemical shifts of 1H and 13C and in some cases also 3He can be used to obtain structural information of these compounds. Such results, together with discussions about different NMR experiments and general considerations regarding sample preparations, are summarized in this chapter. The unique information, both structural and physicochemical, that can be derived from different NMR experiments ensures that this technique will continue to be of central importance in characterization of hydrogenated fullerenes.

  9. NMR studies of cerebral metabolism in vivo

    The nature and extent of the potential synergism between PET and NMR methods is not yet well appreciated in the biomedical community. The long-range interest of medical neurobiology will be well served by efforts of PET and NMR scientists to follow each others' work so that opportunities for productive interchange can be efficiently exploited. Appreciation of the synergism by the rest of the biomedical community will follow naturally. PET is said by the people doing it to be still in its infancy, for they are more concerned with advancing their discipline than with admiring its already impressive achievements. On the scale of the same developmental metaphor, many NMR methods for studying the living human brain are still in utero. The best way to provide the reader a sense of the current status and future course of NMR research in medical neurobiology is by discussion of published in vivo studies. Such a discussion, adapted from another article is what follows

  10. NMR study of hydride systems

    The hydrides of thorium (ThH2, Th4H15 and Th4D15) and the intermetallic compound system (Zr(Vsub(1-x)Cosub(x))2 and its hydrides were investigated using the nuclear magnetic resonance (NMR) technique. From the results for the thorium hydride samples it was concluded that the density of states at the Fermi level n(Esub(f)) is higher in Th4H15 than in ThH2; there is an indirect reaction between the protons and the d electrons belonging to the Th atoms in Th4H15; n(E) has a sharp structure near Esub(f). It was also found that the hydrogen diffusion mechanism changes with temperature. From the results for the intermetallic compound system conclusions were drawn concerning variations in the electronic structure, which explain the behavior of the system. In hydrogen diffusion studies in several samples it was found that Co atoms slow the diffusion rate. Quadrupole spectra obtained at low temperatures show that the H atoms preferably occupy tetrahedral sites formed by three V atoms and one Z atom. (H.K.)

  11. Rheology of Blood by NMR

    Han, Song-I.; Marseille, Oliver; Gehlen, Christa; Blümich, Bernhard

    2001-09-01

    Pipe flow of blood in tubes of 1 and 7 mm inner diameter, respectively, was investigated employing two-dimensional NMR velocity imaging and PFG propagator measurements at different Reynolds numbers between 10 and 3500. The results are compared to flow of a water/glycerol mixture of matching viscosity under identical conditions. The transition from laminar to turbulent flow is observed by both a flattening of the velocity profile and a change of the propagator shape. For blood flow this transition is found to be shifted toward higher Reynolds numbers as compared to the transition of the water/glycerol mixture. This observation is in agreement with predictions from hydraulic measurements and is a consequence of the non-Newtonian flow characteristics of blood as a suspension of erythrocytes and plasma. Likewise, a deviation from the laminar flow condition is observed for blood at low Reynolds numbers between 10 and 100. This phenomenon is unknown for Newtonian liquids and is explained by the onset of a geometrical arrangement of the erythrocytes, the so-called rouleaux effect.

  12. Stable And Oscillating Acoustic Levitation

    Barmatz, Martin B.; Garrett, Steven L.

    1988-01-01

    Sample stability or instability determined by levitating frequency. Degree of oscillation of acoustically levitated object along axis of levitation chamber controlled by varying frequency of acoustic driver for axis above or below frequency of corresponding chamber resonance. Stabilization/oscillation technique applied in normal Earth gravity, or in absence of gravity to bring object quickly to rest at nominal levitation position or make object oscillate in desired range about that position.

  13. Simplified Rotation In Acoustic Levitation

    Barmatz, M. B.; Gaspar, M. S.; Trinh, E. H.

    1989-01-01

    New technique based on old discovery used to control orientation of object levitated acoustically in axisymmetric chamber. Method does not require expensive equipment like additional acoustic drivers of precisely adjustable amplitude, phase, and frequency. Reflecting object acts as second source of sound. If reflecting object large enough, close enough to levitated object, or focuses reflected sound sufficiently, Rayleigh torque exerted on levitated object by reflected sound controls orientation of object.

  14. Passive/Active Acoustic metamaterials

    Lissek, Hervé

    2011-01-01

    Within the last years, an increasing number of studies have been carried out in the field of acoustic metamaterials. These artificial composite materials aim at achieving new macroscopic properties, like negative refraction, that are not readily present in nature. In analogy to electromagnetics, where such concepts are already more mature, a novel concept of artificial acoustic transmission line has recently been reported, which presents such artificial behavior. In this presentation, the des...

  15. Acoustic Invisibility in Turbulent Fluids

    Huang, Xun; Zhong, Siyang

    2013-01-01

    Acoustic invisibility of a cloaking system in turbulent uids has been poorly understood. Here we show that evident scattering would appear in turbulent wakes owing to the submergence of a classical cloaking device. The inherent mechanism is explained using our theoretical model, which eventually inspires us to develop an optimized cloaking approach. Both the near- and far-?eld scatted ?elds are examined using high order computational acoustic methods. The remarkably low scattering demonstrate...

  16. Computational Modeling of Airway Acoustic

    Horáček, Jaromír

    Salt Lake City: National Center for Voice and Speech, University of Utah, 2014. s. 14-14. [International Conference on Voice Physiology and Biomechanics /9./. 10.04.2014-12.04.2014, Salt Lake City] R&D Projects: GA ČR GAP101/12/1306 Institutional support: RVO:61388998 Keywords : biomechanics of voice * finite element method * acoustic waves propagation Subject RIV: BI - Acoustics

  17. NMR studies of multiphase flows II

    Altobelli, S.A.; Caprihan, A.; Fukushima, E. [Lovelace Institutes, Albuquerque, NM (United States)] [and others

    1995-12-31

    NMR techniques for measurements of spatial distribution of material phase, velocity and velocity fluctuation are being developed and refined. Versions of these techniques which provide time average liquid fraction and fluid phase velocity have been applied to several concentrated suspension systems which will not be discussed extensively here. Technical developments required to further extend the use of NMR to the multi-phase flow arena and to provide measurements of previously unobtainable parameters are the focus of this report.

  18. Observation of supramolecular aggregation by dosy NMR

    Šaman, David; Wimmer, Zdeněk; Kolehmainen, E.

    Tatranská Lomnica : Slovak National NMR Centre. Slovak Chemical Society, 2011 - (Liptaj, T.; Imrich, J.; Kovaľaková, M.; Olčák, D.). s. 56-56 ISBN 978-80-89284-77-1. [Magnetic Moments in Central Europe. 16.03.2011-20.03.2011, Tatranská Lomnica] R&D Projects: GA MŠk 2B06024 Institutional research plan: CEZ:AV0Z40550506 Keywords : difusion * NMR Subject RIV: CC - Organic Chemistry

  19. NMR Investigation of the Quantum Piegonhole Effect

    S., Anjusha V.; Hegde, Swathi S.; Mahesh, T. S.

    2015-01-01

    Quantum simulators based on nuclear spin-systems controlled by NMR techniques have been used for studying various quantum phenomena. In this work, using a four-qubit NMR quantum simulator, we investigate the recently postulated quantum pigeon-hole effect. In mathematics, the pigeonhole effect is described by a set of three objects being allocated with only two containers. Classically, one would expect at least one container to accommodate more than one object. However, recently it was predict...

  20. NMR of Membrane Proteins: Beyond Crystals.

    Rajesh, Sundaresan; Overduin, Michael; Bonev, Boyan B

    2016-01-01

    Membrane proteins are essential for the flow of signals, nutrients and energy between cells and between compartments of the cell. Their mechanisms can only be fully understood once the precise structures, dynamics and interactions involved are defined at atomic resolution. Through advances in solution and solid state NMR spectroscopy, this information is now available, as demonstrated by recent studies of stable peripheral and transmembrane proteins. Here we highlight recent cases of G-protein coupled receptors, outer membrane proteins, such as VDAC, phosphoinositide sensors, such as the FAPP-1 pleckstrin homology domain, and enzymes including the metalloproteinase MMP-12. The studies highlighted have resulted in the determination of the 3D structures, dynamical properties and interaction surfaces for membrane-associated proteins using advanced isotope labelling strategies, solubilisation systems and NMR experiments designed for very high field magnets. Solid state NMR offers further insights into the structure and multimeric assembly of membrane proteins in lipid bilayers, as well as into interactions with ligands and targets. Remaining challenges for wider application of NMR to membrane structural biology include the need for overexpression and purification systems for the production of isotope-labelled proteins with fragile folds, and the availability of only a few expensive perdeuterated detergents.Step changes that may transform the field include polymers, such as styrene maleic acid, which obviate the need for detergent altogether, and allow direct high yield purification from cells or membranes. Broader demand for NMR may be facilitated by MODA software, which instantly predicts membrane interactive residues that can subsequently be validated by NMR. In addition, recent developments in dynamic nuclear polarization NMR instrumentation offer a remarkable sensitivity enhancement from low molarity samples and cell surfaces. These advances illustrate the current

  1. Frontiers of NMR in Molecular Biology

    NONE

    1999-08-25

    NMR spectroscopy is expanding the horizons of structural biology by determining the structures and describing the dynamics of blobular proteins in aqueous solution, as well as other classes of proteins including membrane proteins and the polypeptides that form the aggregates diagnostic of prion and amyloid diseases. Significant results are also emerging on DNA and RNA oligomers and their complexes with proteins. This meeting focused attention on key structural questions emanating from molecular biology and how NMR spectroscopy can be used to answer them.

  2. Opto-acoustic cell permeation

    Visuri, S R; Heredia, N

    2000-03-09

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

  3. Prediction of acoustic comfort and acoustic silence in Goan Catholic churches

    Menino A. S. M. P. Tavares; S. Rajagopalan; Satish J. Sharma; António P. O. Carvalho

    2009-01-01

    Acoustic Comfort and Acoustic Silence are determinants of tranquility in a worship space. The results presented here are part of a study that investigates the behaviour of acoustically constituted worship parameters in six Catholic churches (Goa, India). Acoustic comfort is quantified through an Acoustic Comfort Impression Index which measures the net comfort induced through the optimization of the desired subjective acoustic impressions for different types of music and different music source...

  4. 33S NMR cryogenic probe for taurine detection

    Hobo, Fumio; Takahashi, Masato; Maeda, Hideaki

    2009-03-01

    With the goal of a S33 nuclear magnetic resonance (NMR) probe applicable to in vivo NMR on taurine-biological samples, we have developed the S33 NMR cryogenic probe, which is applicable to taurine solutions. The NMR sensitivity gain relative to a conventional broadband probe is as large as 3.5. This work suggests that improvements in the preamplifier could allow NMR measurements on 100 μM taurine solutions, which is the level of sensitivity necessary for biological samples.

  5. Optimized multisectioned acoustic liners

    Baumeister, K. J.

    1979-01-01

    A critical examination is presented of the use of optimized axially segmented acoustic liners to increase the attenuation of a liner. New calculations show that segmenting is most efficient at high frequencies with relatively long duct lengths where the attenuation is low for both uniform and segmented liners. Statistical considerations indicate little advantage in using optimized liners with more than two segments while the bandwidth of an optimized two-segment liner is shown to be nearly equal to that of a uniform liner. Multielement liner calculations show a large degradation in performance due to changes in assumed input modal structure. Finally, in order to substantiate previous and future analytical results, in-house (finite difference) and contractor (mode matching) programs are used to generate theoretical attenuations for a number of liner configurations for liners in a rectangular duct with no mean flow. Overall, the use of optimized multisectioned liners (sometimes called phased liners) fails to offer sufficient advantage over a uniform liner to warrant their use except in low frequency single mode application.

  6. Focusing of Acoustic Waves through Acoustic Materials with Subwavelength Structures

    Xiao, Bingmu

    2013-05-01

    In this thesis, wave propagation through acoustic materials with subwavelength slits structures is studied. Guided by the findings, acoustic wave focusing is achieved with a specific material design. By using a parameter retrieving method, an effective medium theory for a slab with periodic subwavelength cut-through slits is successfully derived. The theory is based on eigenfunction solutions to the acoustic wave equation. Numerical simulations are implemented by the finite-difference time-domain (FDTD) method for the two-dimensional acoustic wave equation. The theory provides the effective impedance and refractive index functions for the equivalent medium, which can reproduce the transmission and reflection spectral responses of the original structure. I analytically and numerically investigate both the validity and limitations of the theory, and the influences of material and geometry on the effective spectral responses are studied. Results show that large contrasts in impedance and density are conditions that validate the effective medium theory, and this approximation displays a better accuracy for a thick slab with narrow slits in it. Based on the effective medium theory developed, a design of a at slab with a snake shaped" subwavelength structure is proposed as a means of achieving acoustic focusing. The property of focusing is demonstrated by FDTD simulations. Good agreement is observed between the proposed structure and the equivalent lens pre- dicted by the theory, which leads to robust broadband focusing by a thin at slab.

  7. PORTABLE ACOUSTIC MONITORING PACKAGE (PAMP)

    John l. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Deepak Mehra

    2003-07-01

    The 1st generation acoustic monitoring package was designed to detect and analyze weak acoustic signals inside natural gas transmission lines. Besides a microphone it housed a three-inch diameter aerodynamic acoustic signal amplifier to maximize sensitivity to leak induced {Delta}p type signals. The theory and test results of this aerodynamic signal amplifier was described in the master's degree thesis of our Research Assistant Deepak Mehra who is about to graduate. To house such a large three-inch diameter sensor required the use of a steel 300-psi rated 4 inch weld neck flange, which itself weighed already 29 pounds. The completed 1st generation Acoustic Monitoring Package weighed almost 100 pounds. This was too cumbersome to mount in the field, on an access port at a pipeline shut-off valve. Therefore a 2nd generation and truly Portable Acoustic Monitor was built. It incorporated a fully self-contained {Delta}p type signal sensor, rated for line pressures up to 1000 psi with a base weight of only 6 pounds. This is the Rosemont Inc. Model 3051CD-Range 0, software driven sensor, which is believed to have industries best total performance. Its most sensitive unit was purchased with a {Delta}p range from 0 to 3 inch water. This resulted in the herein described 2nd generation: Portable Acoustic Monitoring Package (PAMP) for pipelines up to 1000 psi. Its 32-pound total weight includes an 18-volt battery. Together with a 3 pound laptop with its 4-channel data acquisition card, completes the equipment needed for field acoustic monitoring of natural gas transmission pipelines.

  8. Reflective echo tomographic imaging using acoustic beams

    Kisner, Roger; Santos-Villalobos, Hector J

    2014-11-25

    An inspection system includes a plurality of acoustic beamformers, where each of the plurality of acoustic beamformers including a plurality of acoustic transmitter elements. The system also includes at least one controller configured for causing each of the plurality of acoustic beamformers to generate an acoustic beam directed to a point in a volume of interest during a first time. Based on a reflected wave intensity detected at a plurality of acoustic receiver elements, an image of the volume of interest can be generated.

  9. HPLC-NMR revisited: Using time-slice HPLC-SPE-NMR with database assisted dereplication

    Johansen, Kenneth; Wubshet, Sileshi Gizachew; Nyberg, Nils

    2013-01-01

    Time based trapping of chromatographically separated compounds on to solid-phase extraction cartridges (SPE) and subsequent elution to NMR-tubes was done to emulate the function of HPLC–NMR for dereplication purposes. Sufficient mass sensitivity was obtained by the use of a state-of-the-art HPLC...

  10. Use of NMR and NMR Prediction Software to Identify Components in Red Bull Energy Drinks

    Simpson, Andre J.; Shirzadi, Azadeh; Burrow, Timothy E.; Dicks, Andrew P.; Lefebvre, Brent; Corrin, Tricia

    2009-01-01

    A laboratory experiment designed as part of an upper-level undergraduate analytical chemistry course is described. Students investigate two popular soft drinks (Red Bull Energy Drink and sugar-free Red Bull Energy Drink) by NMR spectroscopy. With assistance of modern NMR prediction software they identify and quantify major components in each…