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Sample records for vibrating sample magnetometry

  1. Sub-nano tesla magnetic imaging based on room-temperature magnetic flux sensors with vibrating sample magnetometry

    Science.gov (United States)

    Adachi, Yoshiaki; Oyama, Daisuke

    2017-05-01

    We developed a two-dimensional imaging method for weak magnetic charge distribution using a commercially available magnetic impedance sensor whose magnetic field resolution is 10 pT/Hz1/2 at 10 Hz. When we applied the vibrating sample magnetometry, giving a minute mechanical vibration to the sample and detecting magnetic signals modulated by the vibration frequency, the effects of 1/f noise and the environmental low-frequency band noise were suppressed, and a weak magnetic charge distribution was obtained without magnetic shielding. Furthermore, improvement in the spatial resolution was also expected when the signals were demodulated at the second harmonic frequency of the vibration. In this paper, a preliminary magnetic charge imaging using the vibrating sample magnetometry and its results are demonstrated.

  2. Quantitative analysis of superparamagnetic contrast agent in sentinel lymph nodes using ex vivo vibrating sample magnetometry

    NARCIS (Netherlands)

    Visscher, M.; Pouw, Joost Jacob; van Baarlen, J.; Klaase, J.M.; ten Haken, Bernard

    2013-01-01

    As the first step in developing a new clinical technique for the magnetic detection of colorectal sentinel lymph nodes (SLNs), a method is developed to measure the magnetic content in intact, formalin fixated lymph nodes using a vibrating sample magnetometer (VSM). A suspension of superparamagnetic

  3. Optical Magnetometry

    Science.gov (United States)

    Budker, Dmitry; Kimball, Derek F. Jackson

    2013-03-01

    Part I. Principles and Techniques: 1. General principles and characteristics of optical magnetometers D. F. Jackson Kimball, E. B. Alexandrov and D. Budker; 2. Quantum noise in atomic magnetometers M. V. Romalis; 3. Quantum noise, squeezing, and entanglement in radio-frequency optical magnetometers K. Jensen and E. S. Polzik; 4. Mx and Mz magnetometers E. B. Alexandrov and A. K. Vershovskiy; 5. Spin-exchange-relaxation-free (serf) magnetometers I. Savukov and S. J. Seltzer; 6. Optical magnetometry with modulated light D. F. Jackson Kimball, S. Pustelny, V. V. Yashchuk and D. Budker; 7. Microfabricated atomic magnetometers S. Knappe and J. Kitching; 8. Optical magnetometry with nitrogen-vacancy centers in diamond V. M. Acosta, D. Budker, P. R. Hemmer, J. R. Maze and R. L. Walsworth; 9. Magnetometry with cold atoms W. Gawlik and J. M. Higbie; 10. Helium magnetometers R. E. Slocum, D. D. McGregor and A. W. Brown; 11. Surface coatings for atomic magnetometry S. J. Seltzer, M.-A. Bouchiat and M. V. Balabas; 12. Magnetic shielding V. V. Yashchuk, S.-K. Lee and E. Paperno; Part II. Applications: 13. Remote detection magnetometry S. M. Rochester, J. M. Higbie, B. Patton, D. Budker, R. Holzlöhner and D. Bonaccini Calia; 14. Detection of nuclear magnetic resonance with atomic magnetometers M. P. Ledbetter, I. Savukov, S. J. Seltzer and D. Budker; 15. Space magnetometry B. Patton, A. W. Brown, R. E. Slocum and E. J. Smith; 16. Detection of biomagnetic fields A. Ben-Amar Baranga, T. G. Walker and R. T. Wakai; 17. Geophysical applications M. D. Prouty, R. Johnson, I. Hrvoic and A. K. Vershovskiy; Part III. Broader Impact: 18. Tests of fundamental physics with optical magnetometers D. F. Jackson Kimball, S. K. Lamoreaux and T. E. Chupp; 19. Nuclear magnetic resonance gyroscopes E. A. Donley and J. Kitching; 20. Commercial magnetometers and their application D. C. Hovde, M. D. Prouty, I. Hrvoic and R. E. Slocum; Index.

  4. Trace element content and magnetic properties of commercial HOPG samples studied by ion beam microscopy and SQUID magnetometry

    Directory of Open Access Journals (Sweden)

    D. Spemann

    2014-10-01

    Full Text Available In this study, the impurity concentration and magnetic response of nine highly oriented pyrolytic graphite (HOPG samples with different grades and from different providers were determined using ion beam microscopy and SQUID magnetometry. Apart from sideface contaminations in the as-received state, bulk contamination of the samples in most cases consists of disk-shaped micron-sized particles made of Ti and V with an additional Fe contamination around the grain perimeter. The saturation magnetization typically increases with Fe concentration, however, there is no simple correlation between Fe content and magnetic moment. The saturation magnetization of one, respectively six, out of nine samples clearly exceeds the maximum contribution from pure Fe or Fe3C. For most samples the temperature dependence of the remanence decreases linearly with T – a dependence found previously for defect-induced magnetism (DIM in HOPG. We conclude that apart from magnetic impurities, additional contribution to the ferromagnetic magnetization exists in pristine HOPG in agreement with previous studies. A comparative study between the results of ion beam microscopy and the commonly used EDX analysis shows clearly that EDX is not a reliable method for quantitative trace elemental analysis in graphite, clarifying weaknesses and discrepancies in the element concentrations given in the recent literature.

  5. Remote Nanodiamond Magnetometry

    CERN Document Server

    Ruan, Yinlan; Jeske, Jan; Ebendorff-Heidepriem, Heike; Lau, Desmond W M; Ji, Hong; Johnson, Brett C; Ohshima, Takeshi; V., Shahraam Afshar; Hollenberg, Lloyd; Greentree, Andrew D; Monro, Tanya M; Gibson, Brant C

    2016-01-01

    Optical fibres have transformed the way people interact with the world and now permeate many areas of science. Optical fibres are traditionally thought of as insensitive to magnetic fields, however many application areas from mining to biomedicine would benefit from fibre-based remote magnetometry devices. In this work, we realise such a device by embedding nanoscale magnetic sensors into tellurite glass fibres. Remote magnetometry is performed on magnetically active defect centres in nanodiamonds embedded into the glass matrix. Standard optical magnetometry techniques are applied to initialize and detect local magnetic field changes with a measured sensitivity of 26 micron Tesla/square root(Hz). Our approach utilizes straight-forward optical excitation, simple focusing elements, and low power components. We demonstrate remote magnetometry by direct reporting of the magnetic ground states of nitrogen-vacancy defect centres in the optical fibres. In addition, we present and describe theoretically an all-optica...

  6. The Swarm Magnetometry Package

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Jørgensen, John Leif; Friis-Christensen, Eigil

    2008-01-01

    The Swarm mission under the ESA's Living Planet Programme is planned for launch in 2010 and consists of a constellation of three satellites at LEO. The prime objective of Swarm is to measure the geomagnetic field with unprecedented accuracy in space and time. The magnetometry package consists of ...... of an extremely accurate and stable vector magnetometer, which is co-mounted in an optical bench together with a start tracker system to ensure mechanical stability of the measurements....

  7. Statistical magnetometry on isolated NiCo nanowires and nanowire arrays: a comparative study

    Science.gov (United States)

    Sergelius, Philip; Garcia Fernandez, Javier; Martens, Stefan; Zocher, Michael; Böhnert, Tim; Vega Martinez, Victor; de la Prida, Victor Manuel; Görlitz, Detlef; Nielsch, Kornelius

    2016-04-01

    The first-order reversal curve (FORC) method can be used to extract information about the interaction and switching field distribution of ferromagnetic nanowire arrays, yet it remains challenging to acquire reliable values. Within ordered pores of anodic alumina templates we electrochemically synthesize eight different Ni x Co1-x samples with x varying between 0.05 and 1. FORC diagrams are acquired using vibrating sample magnetometry. By dissolving the template and using the magneto-optical Kerr effect, we measure the hysteresis loops of up to 100 different and isolated nanowires for each sample to gain precise information about the intrinsic switching field distribution. Values of the interaction field are extracted from a deshearing of the major hysteresis loop. We present a comparative study between all methods in order to evaluate and reinforce current FORC theory with experimental findings.

  8. Exchange coupling in hybrid anisotropy magnetic multilayers quantified by vector magnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, C., E-mail: C.Morrison.2@warwick.ac.uk; Miles, J. J.; Thomson, T. [School of Computer Science, University of Manchester, Manchester M13 9PL (United Kingdom); Anh Nguyen, T. N. [Materials Physics, School of ICT, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista (Sweden); Spintronics Research Group, Laboratory for Nanotechnology (LNT), VNU-HCM, Ho Chi Minh City (Viet Nam); Fang, Y.; Dumas, R. K. [Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden); Åkerman, J. [Materials Physics, School of ICT, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista (Sweden); Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden)

    2015-05-07

    Hybrid anisotropy thin film heterostructures, where layers with perpendicular and in-plane anisotropy are separated by a thin spacer, are novel materials for zero/low field spin torque oscillators and bit patterned media. Here, we report on magnetization reversal and exchange coupling in a archetypal Co/Pd (perpendicular)-NiFe (in-plane) hybrid anisotropy system studied using vector vibrating sample magnetometry. This technique allows us to quantify the magnetization reversal in each individual magnetic layer, and measure of the interlayer exchange as a function of non-magnetic spacer thickness. At large (>1 nm) spacer thicknesses Ruderman-Kittel-Kasuya-Yosida-like exchange dominates, with orange-peel coupling providing a significant contribution only for sub-nm spacer thickness.

  9. Atom-specific surface magnetometry

    Science.gov (United States)

    Sirotti, Fausto; Panaccione, Giancarlo; Rossi, Giorgio

    1995-12-01

    A powerful atom-specific surface magnetometry can be based on efficient measurements of magnetic dichroism in l>~0 core level photoemission. The temperature dependence M(T) of the Fe(100) surface magnetization was obtained from the photoemission magnetic asymmetry of 3p core levels, providing the measure of the surface exchange coupling via the spin-wave stiffness and of the surface critical exponent. Beyond the magnetic order the photoemission dichroism allows us to derive the energy splitting of the magnetic sublevels of the photoexcited core hole. Fe 3p photoemission dichroism probes directly the magnetic moment changes of iron atoms at Fe(100) surfaces as a function of structural disorder or sulfur segregation. The appearance of dichroism in the 2p photoemission of segregated sulfur atoms in the c(2×2)S/Fe(100) superstructure measures the magnetic-moment transfer and shows the possibility of investigating surface magnetochemistry in a very direct way.

  10. Cantilever torque magnetometry on coordination compounds

    DEFF Research Database (Denmark)

    Perfetti, Mauro

    2017-01-01

    Cantilever Torque Magnetometry (CTM) is one of the leading techniques to deeply understand magnetic anisotropy of coordination compounds. The knowledge of magnetic anisotropy is a mandatory requirement before proceeding with any future application related to the magnetic properties of coordination...

  11. Atom-specific surface magnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Sirotti, F.; Panaccione, G. [Laboratoire pour l`Utilisation du Rayonnement Electromagnetique, Centre National de la Recherche Scientifique, Commissariat a l`Energie Atomique, MESR, F-91405 Orsay (France); Rossi, G. [Laboratorium fuer Festkoerperphysik, Eidgenossische Technische Hochschule-Zuerich, Zuerich CH-8093 (Switzerland)

    1995-12-15

    A powerful atom-specific surface magnetometry can be based on efficient measurements of magnetic dichroism in {ital l}{gt}0 core level photoemission. The temperature dependence M({ital T}) of the Fe(100) surface magnetization was obtained from the photoemission magnetic asymmetry of 3{ital p} core levels, providing the measure of the surface exchange coupling via the spin-wave stiffness and of the surface critical exponent. Beyond the magnetic order {l_angle}M{r_angle} the photoemission dichroism allows us to derive the energy splitting of the magnetic sublevels of the photoexcited core hole. Fe 3{ital p} photoemission dichroism probes directly the magnetic moment changes of iron atoms at Fe(100) surfaces as a function of structural disorder or sulfur segregation. The appearance of dichroism in the 2{ital p} photoemission of segregated sulfur atoms in the {ital c}(2{times}2)S/Fe(100) superstructure measures the magnetic-moment transfer and shows the possibility of investigating surface magnetochemistry in a very direct way.

  12. Construction and calibration of a low cost and fully automated vibrating sample magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    El-Alaily, T.M., E-mail: toson_alaily@yahoo.com [Physics Department, Faculty of Science, Tanta University, Tanta (Egypt); El-Nimr, M.K.; Saafan, S.A.; Kamel, M.M.; Meaz, T.M. [Physics Department, Faculty of Science, Tanta University, Tanta (Egypt); Assar, S.T. [Engineering Physics and Mathematics Department, Faculty of Engineering, Tanta University, Tanta (Egypt)

    2015-07-15

    A low cost vibrating sample magnetometer (VSM) has been constructed by using an electromagnet and an audio loud speaker; where both are controlled by a data acquisition device. The constructed VSM records the magnetic hysteresis loop up to 8.3 KG at room temperature. The apparatus has been calibrated and tested by using magnetic hysteresis data of some ferrite samples measured by two scientifically calibrated magnetometers; model (Lake Shore 7410) and model (LDJ Electronics Inc. Troy, MI). Our VSM lab-built new design proved success and reliability. - Highlights: • A low cost automated vibrating sample magnetometer VSM has been constructed. • The VSM records the magnetic hysteresis loop up to 8.3 KG at room temperature. • The VSM has been calibrated and tested by using some measured ferrite samples. • Our VSM lab-built new design proved success and reliability.

  13. Magnetometry and archaeological prospection in Mexico

    Science.gov (United States)

    Barba Pingarron, L.; Laboratorio de Prospeccion Arqueologica

    2013-05-01

    Luis Barba Laboratorio de Prospección Arqueológica Instituto de Investigaciones Antropológicas Universidad Nacional Autonoma de México The first magnetic survey in archaeological prospection was published in 1958 in the first number of Archaeometry, in Oxford. That article marked the beginning of this applications to archaeology. After that, magnetic field measurements have become one of the most important and popular prospection tools. Its most outstanding characteristic is the speed of survey that allows to cover large areas in short time. As a consequence, it is usually the first approach to study a buried archaeological site. The first attempts in Mexico were carried out in 196. Castillo and Urrutia, among other geophysical techniques, used a magnetometer to study the northern part of the main plaza, zocalo, in Mexico City to locate some stone Aztec sculptures. About the same time Morrison et al. in La Venta pyramid used a magnetometer to measure total magnetic field trying to find a substructure. Some years later Brainer and Coe made a magnetic survey to locate large stone Olmec heads in San Lorenzo Tenochtitlan, Veracruz. Technology development has provided everyday more portable and accurate instruments to measure the magnetic field. The first total magnetic field proton magnetometers were followed by differential magnetometers and more recently gradiometers. Presently, multiple sensor magnetometers are widely used in European archaeology. The trend has been to remove the environmental and modern interference and to make more sensitive the instruments to the superficial anomalies related to most of the archaeological sites. There is a close relationship between the geology of the region and the way magnetometry works in archaeological sites. Archaeological prospection in Europe usually needs very sensitive instruments to detect slight magnetic contrast of ditches in old sediments. In contrast, volcanic conditions in Mexico produce large magnetic contrast

  14. FORWARD: A toolset for multiwavelength coronal magnetometry

    Directory of Open Access Journals (Sweden)

    Sarah eGibson

    2016-03-01

    Full Text Available Determining the 3D coronal magnetic field is a critical, but extremely difficult problem to solve. Since different types of multiwavelength coronal data probe different aspects of the coronal magnetic field, ideally these data should be used together to validate and constrain specifications of that field. Such a task requires the ability to create observable quantities at a range of wavelengths from a distribution of magnetic field and associated plasma -- i.e., to perform forward calculations. In this paper we describe the capabilities of the FORWARD SolarSoft IDL package, a uniquely comprehensive toolset for coronal magnetometry. FORWARD is a community resource that may be used both to synthesize a broad range of coronal observables, and to access and compare synthetic observables to existing data. It enables forward fitting of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties. FORWARD can also be used to generate synthetic test beds from MHD simulations in order to facilitate the development of coronal magnetometric inversion methods, and to prepare for the analysis of future large solar telescope data.

  15. Spin precession by pulsed inductive magnetometry in thin amorphous plates

    Energy Technology Data Exchange (ETDEWEB)

    Magni, Alessandro; Bottauscio, Oriano; Caprile, Ambra, E-mail: a.caprile@inrim.it; Celegato, Federica; Ferrara, Enzo; Fiorillo, Fausto [Istituto Nazionale di Ricerca Metrologica (INRIM), Electromagnetics Division, Torino 10135 (Italy)

    2014-05-07

    Broadband magnetic loss and damping behavior of Co-based amorphous ribbons and thin films have been investigated. The permeability and loss response of the transverse anisotropy ribbon samples in the frequency range DC to 1 GHz is interpreted in terms of combined and distinguishable contributions to the magnetization process by domain wall displacements and magnetization rotations. The latter alone are shown to survive at the highest frequencies, where the losses are calculated via coupled Maxwell and Landau–Lifshitz–Gilbert (LLG) equations. Remarkably high values of the LLG damping coefficient α = 0.1–0.2 are invoked in this theoretical prediction. Direct measurements of α by pulsed inductive microwave magnetometry are thus performed, both in these laminae and in amorphous films of identical composition, obtaining about one order of magnitude increase of the α value upon the 100 nm÷10 μm thickness range. This confirms that dissipation by eddy currents enters the LLG equation via large increase of the damping coefficient.

  16. Spin precession by pulsed inductive magnetometry in thin amorphous plates

    Science.gov (United States)

    Magni, Alessandro; Bottauscio, Oriano; Caprile, Ambra; Celegato, Federica; Ferrara, Enzo; Fiorillo, Fausto

    2014-05-01

    Broadband magnetic loss and damping behavior of Co-based amorphous ribbons and thin films have been investigated. The permeability and loss response of the transverse anisotropy ribbon samples in the frequency range DC to 1 GHz is interpreted in terms of combined and distinguishable contributions to the magnetization process by domain wall displacements and magnetization rotations. The latter alone are shown to survive at the highest frequencies, where the losses are calculated via coupled Maxwell and Landau-Lifshitz-Gilbert (LLG) equations. Remarkably high values of the LLG damping coefficient α = 0.1-0.2 are invoked in this theoretical prediction. Direct measurements of α by pulsed inductive microwave magnetometry are thus performed, both in these laminae and in amorphous films of identical composition, obtaining about one order of magnitude increase of the α value upon the 100 nm÷10 μm thickness range. This confirms that dissipation by eddy currents enters the LLG equation via large increase of the damping coefficient.

  17. Vibration Frequencies Extraction of the Forth Road Bridge Using High Sampling GPS Data

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2016-01-01

    Full Text Available This paper proposes a scheme for vibration frequencies extraction of the Forth Road Bridge in Scotland from high sampling GPS data. The interaction between the dynamic response and the ambient loadings is carefully analysed. A bilinear Chebyshev high-pass filter is designed to isolate the quasistatic movements, the FFT algorithm and peak-picking approach are applied to extract the vibration frequencies, and a GPS data accumulation counter is suggested for real-time monitoring applications. To understand the change in the structural characteristics under different loadings, the deformation results from three different loading conditions are presented, that is, the ambient circulation loading, the strong wind under abrupt wind speed change, and the specific trial with two 40 t lorries passing the bridge. The results show that GPS not only can capture absolute 3D deflections reliably, but also can be used to extract the frequency response accurately. It is evident that the frequencies detected using the filtered deflection time series in different direction show quite different characteristics, and more stable results can be obtained from the height displacement time series. The frequency responses of 0.105 and 0.269 Hz extracted from the lateral displacement time series correlate well with the data using height displacement time series.

  18. Software interface and data acquisition package for the LakeShore cryogenics vibrating sample magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    O`Dell, B.H.

    1995-11-01

    A software package was developed to replace the software provided by LakeShore for their model 7300 vibrating sample magnetometer (VSM). Several problems with the original software`s functionality caused this group to seek a new software package. The new software utilizes many features that were unsupported in the LakeShore software, including a more functional step mode, point averaging mode, vector moment measurements, and calibration for field offset. The developed software interfaces the VSM through a menu driven graphical user interface, and bypasses the VSM`s on board processor leaving control of the VSM up to the software. The source code for this software is readily available to any one. By having the source, the experimentalist has full control of data acquisition and can add routines specific to their experiment.

  19. A comparison of Solar proxy-magnetometry diagnostics

    NARCIS (Netherlands)

    Leenaarts, J.|info:eu-repo/dai/nl/304837946; Rutten, R.J.|info:eu-repo/dai/nl/074143662; Carlsson, M.; Uitenbroek, H.

    2006-01-01

    Aims. We test various proxy-magnetometry diagnostics, i.e., brightness signatures of small-scale magnetic elements, for studying magnetic field structures in the solar photosphere. Methods. Images are numerically synthesized from a 3D solar magneto-convection simulation for, respectively, the G band

  20. Synthesis and Characterization of Mixed Iron-Manganese Oxide Nanoparticles and Their Application for Efficient Nickel Ion Removal from Aqueous Samples

    OpenAIRE

    Buccolieri, Alessandro; Serra, Antonio; Maruccio, Giuseppe; Monteduro, Anna Grazia; Padmanabhan, Sanosh Kunjalukkal; Licciulli, Antonio; Bonfrate, Valentina; Salvatore, Luca; Manno, Daniela; Calcagnile, Lucio; Giancane, Gabriele

    2017-01-01

    Mixed iron-manganese oxide nanoparticles, synthesized by a simple procedure, were used to remove nickel ion from aqueous solutions. Nanostructures, prepared by using different weight percents of manganese, were characterized by transmission electron microscopy, selected area diffraction, X-ray diffraction, Raman spectroscopy, and vibrating sample magnetometry. Adsorption/desorption isotherm curves demonstrated that manganese inclusions enhance the specific surface area three times and the por...

  1. Sample presentation, sources of error and future perspectives on the application of vibrational spectroscopy in the wine industry.

    Science.gov (United States)

    Cozzolino, Daniel

    2015-03-30

    Vibrational spectroscopy encompasses a number of techniques and methods including ultra-violet, visible, Fourier transform infrared or mid infrared, near infrared and Raman spectroscopy. The use and application of spectroscopy generates spectra containing hundreds of variables (absorbances at each wavenumbers or wavelengths), resulting in the production of large data sets representing the chemical and biochemical wine fingerprint. Multivariate data analysis techniques are then required to handle the large amount of data generated in order to interpret the spectra in a meaningful way in order to develop a specific application. This paper focuses on the developments of sample presentation and main sources of error when vibrational spectroscopy methods are applied in wine analysis. Recent and novel applications will be discussed as examples of these developments. © 2014 Society of Chemical Industry.

  2. Direct surface magnetometry with photoemission magnetic x-ray dichroism

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, J.G.; Goodman, K.W. [Lawrence Berkeley National Lab., CA (United States); Schumann, F.O. [Pennsylvania State Univ., University Park, PA (United States)] [and others

    1997-04-01

    Element specific surface magnetometry remains a central goal of synchrotron radiation based studies of nanomagnetic structures. One appealing possibility is the combination of x-ray absorption dichroism measurements and the theoretical framework provided by the {open_quotes}sum rules.{close_quotes} Unfortunately, sum rule analysis are hampered by several limitations including delocalization of the final state, multi-electronic phenomena and the presence of surface dipoles. An alternative experiment, Magnetic X-Ray Dichroism in Photoelectron Spectroscopy, holds out promise based upon its elemental specificity, surface sensitivity and high resolution. Computational simulations by Tamura et al. demonstrated the relationship between exchange and spin orbit splittings and experimental data of linear and circular dichroisms. Now the authors have developed an analytical framework which allows for the direct extraction of core level exchange splittings from circular and linear dichroic photoemission data. By extending a model initially proposed by Venus, it is possible to show a linear relation between normalized dichroism peaks in the experimental data and the underlying exchange splitting. Since it is reasonable to expect that exchange splittings and magnetic moments track together, this measurement thus becomes a powerful new tool for direct surface magnetometry, without recourse to time consuming and difficult spectral simulations. The theoretical derivation will be supported by high resolution linear and circular dichroism data collected at the Spectromicroscopy Facility of the Advanced Light Source.

  3. Measurement of intravenously administered γ-Fe2O3 particle amount in mice tissues using vibrating sample magnetometer.

    Science.gov (United States)

    Kishimoto, Mikio; Miyamoto, Ryoichi; Oda, Tatsuya; Ohara, Yusuke; Yanagihara, Hideto; Ohkohchi, Nobuhiro; Kita, Eiji

    2014-12-01

    Dispersions of platelet γ-Fe2O3 particles 30-50nm in size were intravenously administered to mice and the amount of particles accumulated in each tissue was obtained by magnetization measurement using a vibrating sample magnetometer. Background noise was greatly reduced by measuring dried tissues under a magnetic field of 500 Oe so that the effect of diamagnetism was slight. Remarkable particle accumulation was observed in the liver and spleen. Considerable particle accumulation was observed in the lung when a large quantity of γ-Fe2 O3 particles was administered. There was no significant particle accumulation in the kidney and heart.

  4. An optimal sampling approach to modelling whole-body vibration exposure in all-terrain vehicle driving.

    Science.gov (United States)

    Lü, Xiaoshu; Takala, Esa-Pekka; Toppila, Esko; Marjanen, Ykä; Kaila-Kangas, Leena; Lu, Tao

    2017-08-01

    Exposure to whole-body vibration (WBV) presents an occupational health risk and several safety standards obligate to measure WBV. The high cost of direct measurements in large epidemiological studies raises the question of the optimal sampling for estimating WBV exposures given by a large variation in exposure levels in real worksites. This paper presents a new approach to addressing this problem. A daily exposure to WBV was recorded for 9-24 days among 48 all-terrain vehicle drivers. Four data-sets based on root mean squared recordings were obtained from the measurement. The data were modelled using semi-variogram with spectrum analysis and the optimal sampling scheme was derived. The optimum sampling period was 140 min apart. The result was verified and validated in terms of its accuracy and statistical power. Recordings of two to three hours are probably needed to get a sufficiently unbiased daily WBV exposure estimate in real worksites. The developed model is general enough that is applicable to other cumulative exposures or biosignals. Practitioner Summary: Exposure to whole-body vibration (WBV) presents an occupational health risk and safety standards obligate to measure WBV. However, direct measurements can be expensive. This paper presents a new approach to addressing this problem. The developed model is general enough that is applicable to other cumulative exposures or biosignals.

  5. Stabilized Skyrmion Phase Detected in MnSi Nanowires by Dynamic Cantilever Magnetometry.

    Science.gov (United States)

    Mehlin, A; Xue, F; Liang, D; Du, H F; Stolt, M J; Jin, S; Tian, M L; Poggio, M

    2015-07-08

    Using dynamic cantilever magnetometry we measure an enhanced skyrmion lattice phase extending from around 29 K down to at least 0.4 K in single MnSi nanowires (NWs). Although recent experiments on two-dimensional thin films show that reduced dimensionality stabilizes the skyrmion phase, our results are surprising given that the NW dimensions are much larger than the skyrmion lattice constant. Furthermore, the stability of the phase depends on the orientation of the NWs with respect to the applied magnetic field, suggesting that an effective magnetic anisotropy, likely due to the large surface-to-volume ratio of these nanostructures, is responsible for the stabilization. The compatibility of our technique with nanometer-scale samples paves the way for future studies on the effect of confinement and surfaces on magnetic skyrmions.

  6. Magnetic properties of cobalt microwires measured by piezoresistive cantilever magnetometry

    Directory of Open Access Journals (Sweden)

    Tosolini G.

    2014-09-01

    Full Text Available We present the magnetic characterization of cobalt wires grown by focused electron beam-induced deposition (FEBID and studied using static piezoresistive cantilever magnetometry. We have used previously developed high force sensitive submicron-thick silicon piezoresistive cantilevers. High quality polycrystalline cobalt microwires have been grown by FEBID onto the free end of the cantilevers using dual beam equipment. In the presence of an external magnetic field, the magnetic cobalt wires become magnetized, which leads to the magnetic field dependent static deflection of the cantilevers. We show that the piezoresistive signal from the cantilevers, corresponding to a maximum force of about 1 nN, can be measured as a function of the applied magnetic field with a good signal to noise ratio at room temperature. The results highlight the flexibility of the FEBID technique for the growth of magnetic structures on specific substrates, in this case piezoresistive cantilevers.

  7. Probing High Temperature Superconductors with Magnetometry in Ultrahigh Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lu [Univ. of Michigan, Ann Arbor, MI (United States)

    2017-07-26

    The objective of this research is to investigate the high-field magnetic properties of high temperature superconductors, materials that conduct electricity without loss. A technique known as high-resolution torque magnetometry that was developed to directly measure the magnetization of high temperature superconductors. This technique was implemented using the 65 Tesla pulsed magnetic field facility that is part of the National High Magnetic Field Laboratory at Los Alamos National Laboratory. This research addressed unanswered questions about the interplay between magnetism and superconductivity, determine the electronic structure of high temperature superconductors, and shed light on the mechanism of high temperature superconductivity and on potential applications of these materials in areas such as energy generation and power transmission. Further applications of the technology resolve the novel physical phenomena such as correlated topological insulators, and spin liquid state in quantum magnets.

  8. Mercury's Surface Magnetic Field Determined from Proton-Reflection Magnetometry

    Science.gov (United States)

    Winslow, Reka M.; Johnson, Catherine L.; Anderson, Brian J.; Gershman, Daniel J.; Raines, Jim M.; Lillis, Robert J.; Korth, Haje; Slavin, James A.; Solomon, Sean C.; Zurbuchen, Thomas H.; hide

    2014-01-01

    Solar wind protons observed by the MESSENGER spacecraft in orbit about Mercury exhibit signatures of precipitation loss to Mercury's surface. We apply proton-reflection magnetometry to sense Mercury's surface magnetic field intensity in the planet's northern and southern hemispheres. The results are consistent with a dipole field offset to the north and show that the technique may be used to resolve regional-scale fields at the surface. The proton loss cones indicate persistent ion precipitation to the surface in the northern magnetospheric cusp region and in the southern hemisphere at low nightside latitudes. The latter observation implies that most of the surface in Mercury's southern hemisphere is continuously bombarded by plasma, in contrast with the premise that the global magnetic field largely protects the planetary surface from the solar wind.

  9. SQUID magnetometry from nanometer to centimeter length scales

    Science.gov (United States)

    Hatridge, Michael Jonathan

    Information stored in magnetic fields plays an important role in everyday life. This information exists over a remarkably wide range of sizes, so that magnetometry at a variety of length scales can extract useful information. Examples at centimeter to millimeter length scales include measurement of spatial and temporal character of fields generated in the human brain and heart, and active manipulation of spins in the human body for non-invasive magnetic resonance imaging (MRI). At micron length scales, magnetometry can be used to measure magnetic objects such as flux qubits; at nanometer length scales it can be used to study individual magnetic domains, and even individual spins. The development of Superconducting QUantum Interference Device (SQUID) based magnetometer for two such applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nanoscale magnetometry, are the focus of this thesis. Conventional MRI has developed into a powerful clinical tool for imaging the human body. This technique is based on nuclear magnetic resonance of protons with the addition application of three-dimensional magnetic field gradients to encode spatial information. Most clinical MRI systems involve magnetic fields generated by superconducting magnets, and the current trend is to higher magnetic fields than the widely used 1.5-T systems. Nonetheless, there is ongoing interest in the development of less expensive imagers operating at lower fields. The prepolarized, SQUID detected ultra-low field MRI (ULF MRI) developed by the Clarke group allows imaging in very weak fields (typically 132 muT, corresponding to a resonant frequency of 5.6 kHz). At these low field strengths, there is enhanced contrast in the longitudinal relaxation time of various tissue types, enabling imaging of objects which are not visible to conventional MRI, for instance prostate cancer. We are currently investigating the contrast between normal and cancerous

  10. Inversion of potential field data : theory and applications in gravimetry and magnetometry

    NARCIS (Netherlands)

    Mirzaei, M.

    1996-01-01

    This thesis deals with the inversion of potential field data. Theoretical aspects and applications in gravimetry and magnetometry are treated. Inverse theory provides mathematical techniques to obtain useful infonnation about the earth based on measurements (data). These techniques estimate

  11. Blind identification of full-field vibration modes of output-only structures from uniformly-sampled, possibly temporally-aliased (sub-Nyquist), video measurements

    Science.gov (United States)

    Yang, Yongchao; Dorn, Charles; Mancini, Tyler; Talken, Zachary; Nagarajaiah, Satish; Kenyon, Garrett; Farrar, Charles; Mascareñas, David

    2017-03-01

    Enhancing the spatial and temporal resolution of vibration measurements and modal analysis could significantly benefit dynamic modelling, analysis, and health monitoring of structures. For example, spatially high-density mode shapes are critical for accurate vibration-based damage localization. In experimental or operational modal analysis, higher (frequency) modes, which may be outside the frequency range of the measurement, contain local structural features that can improve damage localization as well as the construction and updating of the modal-based dynamic model of the structure. In general, the resolution of vibration measurements can be increased by enhanced hardware. Traditional vibration measurement sensors such as accelerometers have high-frequency sampling capacity; however, they are discrete point-wise sensors only providing sparse, low spatial sensing resolution measurements, while dense deployment to achieve high spatial resolution is expensive and results in the mass-loading effect and modification of structure's surface. Non-contact measurement methods such as scanning laser vibrometers provide high spatial and temporal resolution sensing capacity; however, they make measurements sequentially that requires considerable acquisition time. As an alternative non-contact method, digital video cameras are relatively low-cost, agile, and provide high spatial resolution, simultaneous, measurements. Combined with vision based algorithms (e.g., image correlation or template matching, optical flow, etc.), video camera based measurements have been successfully used for experimental and operational vibration measurement and subsequent modal analysis. However, the sampling frequency of most affordable digital cameras is limited to 30-60 Hz, while high-speed cameras for higher frequency vibration measurements are extremely costly. This work develops a computational algorithm capable of performing vibration measurement at a uniform sampling frequency lower than

  12. Structure-based sampling and self-correcting machine learning for accurate calculations of potential energy surfaces and vibrational levels

    Science.gov (United States)

    Dral, Pavlo O.; Owens, Alec; Yurchenko, Sergei N.; Thiel, Walter

    2017-06-01

    We present an efficient approach for generating highly accurate molecular potential energy surfaces (PESs) using self-correcting, kernel ridge regression (KRR) based machine learning (ML). We introduce structure-based sampling to automatically assign nuclear configurations from a pre-defined grid to the training and prediction sets, respectively. Accurate high-level ab initio energies are required only for the points in the training set, while the energies for the remaining points are provided by the ML model with negligible computational cost. The proposed sampling procedure is shown to be superior to random sampling and also eliminates the need for training several ML models. Self-correcting machine learning has been implemented such that each additional layer corrects errors from the previous layer. The performance of our approach is demonstrated in a case study on a published high-level ab initio PES of methyl chloride with 44 819 points. The ML model is trained on sets of different sizes and then used to predict the energies for tens of thousands of nuclear configurations within seconds. The resulting datasets are utilized in variational calculations of the vibrational energy levels of CH3Cl. By using both structure-based sampling and self-correction, the size of the training set can be kept small (e.g., 10% of the points) without any significant loss of accuracy. In ab initio rovibrational spectroscopy, it is thus possible to reduce the number of computationally costly electronic structure calculations through structure-based sampling and self-correcting KRR-based machine learning by up to 90%.

  13. Magnetism Matters: Coronal Magnetometry Using Multi-Wavelength Polarimetry

    Science.gov (United States)

    Gibson, Sarah E.

    2015-08-01

    The solar coronal magnetic field is key both to solving fundamental problems in solar physics such as coronal heating and solar wind acceleration, and to predicting the internal magnetic structure and thus space-weather impact of coronal mass ejections. I will describe the current state of the art in coronal magnetometry, and present results from the Coronal Multichannel Polarimeter (CoMP) at Mauna Loa Solar Observatory (MLSO), which since 2011 has taken polarimetric observations of the solar corona in the near-infrared on a near-daily basis. I will discuss work in progress that utilizes forward modeling to synthesize polarimetric data at multiple heights and vantage points, and at wavelengths from radio to infrared to visible to ultraviolet. The goal is to use such synthetic testbeds to determine the ideal set of observations for constraining the coronal magnetic field, and to establish a Data-Optimized Coronal Field Model (DOC-FM) that efficiently incorporates these data into global magnetic models. This work will provide essential tools and motivation for the planning and implementation of future coronal polarimetric projects and missions spanning a broad range of wavelengths.

  14. A Moessbauer spectroscopy and magnetometry study of magnetic multilayers and oxides

    CERN Document Server

    Bland, J

    2002-01-01

    A study of the magnetic properties of thin films, multilayers and oxides has been performed using Moessbauer spectroscopy and SQUID magnetometry. The systems studied are DyFe sub 2 , HoFe sub 2 and YFe sub 2 cubic Laves Phase thin films, DyFe sub 2 /Dy and DyFe sub 2 /YFe sub 2 multilayers; Ce/Fe and U/Fe multilayers; and iron oxide powders and thin films. CEMS results at room temperature show a low symmetry magnetic easy axis for all of the Laves Phase samples studied. Analysis of the dipolar and contact hyperfine fields show that this axis is close to the [2-bar41] and [3-bar51] directions but cannot be fully determined. The spin moments lie out of plane in all samples by approximately 22 deg, indicating a significant magneto-elastic anisotropy. 2.5 kG inplane applied field measurements indicate a much larger magnitude of magnetocrystalline anisotropy in the DyFe sub 2 system than in the YFe sub 2 system. In the DyFe sub 2 /YFe sub 2 multilayer samples the anisotropy is dominated by the dysprosium single-io...

  15. Stray-field-induced Faraday contributions in wide-field Kerr microscopy and -magnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Markó, D.; Soldatov, I. [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Institute for Metallic Materials, PO 270116, D-01171 Dresden (Germany); Dresden University of Technology, Institute for Materials Science, D-01062 Dresden (Germany); Tekielak, M. [Institute of Experimental Physics, University of Bialystok, Lipowa 41, Bialystok 15-424 Poland (Poland); Schäfer, R., E-mail: r.schaefer@ifw-dresden.de [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Institute for Metallic Materials, PO 270116, D-01171 Dresden (Germany); Dresden University of Technology, Institute for Materials Science, D-01062 Dresden (Germany)

    2015-12-15

    The magnetic domain contrast in wide-field Kerr microscopy on bulk specimens can be substantially distorted by non-linear, field-dependent Faraday rotations in the objective lens that are caused by stray-field components emerging from the specimen. These Faraday contributions, which were detected by Kerr-magnetometry on grain-oriented iron–silicon steel samples, are thoroughly elaborated and characterized. They express themselves as a field-dependent gray-scale offset to the domain contrast and in highly distorted surface magnetization curves if optically measured in a wide field Kerr microscope. An experimental method to avoid such distortions is suggested. In the course of these studies, a low-permeability part in the surface magnetization loop of slightly misoriented (110)-surfaces in iron–silicon sheets was discovered that is attributed to demagnetization effects in direction perpendicular to the sheet surface. - Highlights: • Magnetizing a finite sample in a Kerr microscope leads to sample-generated stray-fields. • They cause non-linear, field- and position-dependent Faraday rotations in the objective. • This leads to a modulation of the Kerr contrast and to distorted MOKE loops. • A method to compensate these Faraday rotations is presented.

  16. Vibrating sample magnetometer 2D and 3D magnetization effects associated with different initial magnetization states

    Directory of Open Access Journals (Sweden)

    Ronald E. Lukins

    2017-05-01

    Full Text Available Differences in VSM magnetization vector rotation associated with various initial magnetization states were demonstrated. Procedures and criteria were developed to select sample orientation and initial magnetization states to allow for the combination of two different 2D measurements runs (with the same field profiles to generate a dataset that can be representative of actual 3D magnetization rotation. Nickel, cast iron, and low moment magnetic tape media were used to demonstrate these effects using hysteresis and remanent magnetization test sequences. These results can be used to generate 2D and 3D magnetic properties to better characterize magnetic phenomena which are inherently three dimensional. Example applications are magnetic tape-head orientation sensitivity, reinterpretation of 3D coercivity and other standard magnetic properties, and multi-dimensional shielding effectiveness.

  17. Vibration and acoustic frequency spectra for industrial process modeling using selective fusion multi-condition samples and multi-source features

    Science.gov (United States)

    Tang, Jian; Qiao, Junfei; Wu, ZhiWei; Chai, Tianyou; Zhang, Jian; Yu, Wen

    2018-01-01

    Frequency spectral data of mechanical vibration and acoustic signals relate to difficult-to-measure production quality and quantity parameters of complex industrial processes. A selective ensemble (SEN) algorithm can be used to build a soft sensor model of these process parameters by fusing valued information selectively from different perspectives. However, a combination of several optimized ensemble sub-models with SEN cannot guarantee the best prediction model. In this study, we use several techniques to construct mechanical vibration and acoustic frequency spectra of a data-driven industrial process parameter model based on selective fusion multi-condition samples and multi-source features. Multi-layer SEN (MLSEN) strategy is used to simulate the domain expert cognitive process. Genetic algorithm and kernel partial least squares are used to construct the inside-layer SEN sub-model based on each mechanical vibration and acoustic frequency spectral feature subset. Branch-and-bound and adaptive weighted fusion algorithms are integrated to select and combine outputs of the inside-layer SEN sub-models. Then, the outside-layer SEN is constructed. Thus, ;sub-sampling training examples;-based and ;manipulating input features;-based ensemble construction methods are integrated, thereby realizing the selective information fusion process based on multi-condition history samples and multi-source input features. This novel approach is applied to a laboratory-scale ball mill grinding process. A comparison with other methods indicates that the proposed MLSEN approach effectively models mechanical vibration and acoustic signals.

  18. Micro-Hall magnetometry on a Co-organic chain compound

    Energy Technology Data Exchange (ETDEWEB)

    Rolland, L.; Simonet, V. E-mail: simonet@grenoble.cnrs.fr; Wernsdorfer, W.; Bogani, L.; Sessoli, R

    2004-05-01

    The static and dynamical properties of Co-organic chains, with strong magnetic anisotropy, are studied by micro-Hall magnetometry. The low-temperature hysteresis cycles are discussed with respect to the helical structure of the chains. Thermally activated relaxation of the magnetization is observed, compatible with the Glauber model for a 1D Ising system.

  19. Pump-Enhanced Continuous-Wave Magnetometry Using Nitrogen-Vacancy Ensembles

    DEFF Research Database (Denmark)

    Ahmadi, Sepehr; El-Ella, Haitham A. R.; Hansen, Jørn Otto Bindslev

    2017-01-01

    Ensembles of nitrogen-vacancy centers in diamond are a highly promisingplatform for high-sensitivity magnetometry, whose efficacy is often based onefficiently generating and monitoring magnetic-field dependent infraredfluorescence. Here we report on an increased sensing efficiency with the use ofa...

  20. In-flight scalar calibration and characterisation of the Swarm magnetometry package

    DEFF Research Database (Denmark)

    Tøffner-Clausen, Lars; Lesur, Vincent; Olsen, Nils

    2016-01-01

    We present the in-flight scalar calibration and characterisation of the Swarm magnetometry package consisting of the absolute scalar magnetometer, the vector magnetometer, and the spacecraft structure supporting the instruments. A significant improvement in the scalar residuals between the pairs ...

  1. Urban vibrations

    DEFF Research Database (Denmark)

    Morrison, Ann; Knudsen, L.; Andersen, Hans Jørgen

    2012-01-01

      lab   studies   in   that   we   found   a   decreased   detection   rate   in   busy   environments.   Here   we   test   with   a   much   larger   sample   and   age   range,   and   contribute   with   the   first   vibration  sensitivity  testing  outside  the  lab  in  an  urban   public...

  2. Effective field analysis using the full angular spin-orbit torque magnetometry dependence

    Science.gov (United States)

    Schulz, Tomek; Lee, Kyujoon; Krüger, Benjamin; Lo Conte, Roberto; Karnad, Gurucharan V.; Garcia, Karin; Vila, Laurent; Ocker, Berthold; Ravelosona, Dafiné; Kläui, Mathias

    2017-06-01

    Spin-orbit torques promise ultraefficient magnetization switching used for advanced devices based on emergent quasiparticles such as domain walls and skyrmions. Recently, the spin structure dynamics, materials, and systems with tailored spin-orbit torques are being developed. A method, which allows one to detect the acting torques in a given system as a function of the magnetization direction is the torque magnetometry method based on a higher harmonics analysis of the anomalous Hall effect. Here we show that the effective fields acting on magnetic domain walls that govern the efficiency of their dynamics require a sophisticated analysis taking into account the full angular dependence of the torques. Using a one-dimensional model, we compared the spin-orbit torque efficiencies by depinning measurements and spin torque magnetometry. We show that the effective fields can be accurately determined and we find good agreement. Thus, our method allows us now to rapidly screen materials and predict the resulting quasiparticle dynamics.

  3. A SQUID magnetometry system for a cryogenic neutron electric dipole moment experiment

    Energy Technology Data Exchange (ETDEWEB)

    Henry, S., E-mail: s.henry@physics.ox.ac.uk; Clarke, C.; Cottle, A.; Lynch, A.; Pipe, M.

    2014-11-01

    Precision magnetometry is an essential component of any neutron electric dipole moment experiment in order to correct shifts in the neutron precession frequency due to changes in the magnetic field. We have developed a magnetometry system using 12 SQUID sensors, designed to operate in 0.5 K superfluid helium. The pick-up loops located near the neutron cell are connected to the SQUID sensors by ∼2 m twisted wire pairs. The SQUID readout cables are run via an intermediate stage at 4.2 K. The system has been installed and tested in the cryoEDM apparatus at the ILL, Grenoble, and used to characterise the magnetic environment. Further tests in a suitable low noise environment confirm it meets our requirements.

  4. Ultracold Field Gradient Magnetometry and Transport to Study Correlated Topological Phases

    Science.gov (United States)

    2016-10-01

    magnetism and correlation effects in f-electron systems. This project aims at the discovery of emergent topological phases “beyond band theory.” In order...PROGRAM ELEMENT NUMBER 5b. GRANT NUMBER 5a. CONTRACT NUMBER Form Approved OMB NO. 0704-0188 3. DATES COVERED (From - To) - Approved for Public ...Release; Distribution Unlimited UU UU UU UU 01-10-2016 1-Jul-2015 30-Jun-2016 Final Report: Ultracold Field Gradient Magnetometry and Transport to Study

  5. In situ magnetometry for experiments with atomic quantum gases

    Science.gov (United States)

    Krinner, Ludwig; Stewart, Michael; Pazmiño, Arturo; Schneble, Dominik

    2018-01-01

    Precise control of magnetic fields is a frequent challenge encountered in experiments with atomic quantum gases. Here we present a simple method for performing in situ monitoring of magnetic fields that can readily be implemented in any quantum-gas apparatus in which a dedicated field-stabilization approach is not feasible. The method, which works by sampling several Rabi resonances between magnetically field sensitive internal states that are not otherwise used in a given experiment, can be integrated with standard measurement sequences at arbitrary fields. For a condensate of 87Rb atoms, we demonstrate the reconstruction of Gauss-level bias fields with an accuracy of tens of microgauss and with millisecond time resolution. We test the performance of the method using measurements of slow resonant Rabi oscillations on a magnetic-field sensitive transition and give an example for its use in experiments with state-selective optical potentials.

  6. 49 CFR 178.819 - Vibration test.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Vibration test. 178.819 Section 178.819... Testing of IBCs § 178.819 Vibration test. (a) General. The vibration test must be conducted for the... vibration test. (b) Test method. (1) A sample IBC, selected at random, must be filled and closed as for...

  7. Application of SQUIDs to low temperature and high magnetic field measurements—Ultra low noise torque magnetometry

    Science.gov (United States)

    Arnold, F.; Naumann, M.; Lühmann, Th.; Mackenzie, A. P.; Hassinger, E.

    2018-02-01

    Torque magnetometry is a key method to measure the magnetic anisotropy and quantum oscillations in metals. In order to resolve quantum oscillations in sub-millimeter sized samples, piezo-electric micro-cantilevers were introduced. In the case of strongly correlated metals with large Fermi surfaces and high cyclotron masses, magnetic torque resolving powers in excess of 104 are required at temperatures well below 1 K and magnetic fields beyond 10 T. Here, we present a new broadband read-out scheme for piezo-electric micro-cantilevers via Wheatstone-type resistance measurements in magnetic fields up to 15 T and temperatures down to 200 mK. By using a two-stage superconducting-quantum interference device as a null detector of a cold Wheatstone bridge, we were able to achieve a magnetic moment resolution of Δm = 4 × 10-15 J/T at maximal field and 700 mK, outperforming conventional magnetometers by at least one order of magnitude in this temperature and magnetic field range. Exemplary de Haas-van Alphen measurement of a newly grown delafossite, PdRhO2, was used to show the superior performance of our setup.

  8. Vectorial magnetometry and anisotropy studies on thin Co{sub 50}Fe{sub 50} films using MOKE

    Energy Technology Data Exchange (ETDEWEB)

    Kuschel, Timo; Wollschlaeger, Joachim [Fachbereich Physik, Universitaet Osnabrueck, Barbarastr. 7, 49069 Osnabrueck (Germany); Hamrle, Jaroslav; Pistora, Jaromir [Department of Physics, VSB - Technical University of Ostrava, 17. listopadu 15, 70833 Ostrava-Poruba (Czech Republic); Bosu, Subrojati; Sakuraba, Yuya; Takanashi, Koki [Institute for Materials Research (IMR), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan)

    2011-07-01

    Magnetooptical Kerr effect (MOKE) is a powerful tool to determine magnetic properties of thin magnetic films. In some cases this technique is only applied to detect magnetization curves qualitatively. In order to perform a quantitative analysis we present MOKE measurements with s- and p-polarized incident light, using an external magnetic field either parallel or perpendicular to the plane of incidence of light and different orientations of the crystalline substrate. The processing of the data includes vectorial magnetometry as well as studies of the anisotropy constants and magnetic axes. The investigated Co{sub 50}Fe{sub 50} films o f 50 nm thickness on MgO(001) are prepared with different annealing temperatures (RT up to 400 C). On the one hand the films with lower annealing tempe ratures show typical magnetic reversal processes of samples with four-fold symmetry as expected for cubic crystal structures. On the other hand the film annealed at 400 C presents an additional strong in-plane anisotropy, which is discussed in context of a classical free energy approach.

  9. Confirmation by SQUID magnetometry of FMR measurements of magnetization in ultrathin Fe-B amorphous films

    Science.gov (United States)

    Zhang, Lu; Rado, George T.

    1987-04-01

    Direct measurements were made by means of SQUID magnetometry of the magnetization of ultrathin Fe50B50 and Fe70B30 amorphous films at room temperature. The film thicknesses used included most of those investigated in the authors' recent ferromagnetic resonance (FMR) determinations of the surface anisotropy Ks and the magnetization M of such films. The directly measured values of M confirm adequately the M values obtained by computer fitting of a theory to experimental FMR data. Thus, the present experiments offer substantial support for the reliability of the FMR method for measurements of Ks and M in ultrathin films.

  10. Coronal magnetometry

    CERN Document Server

    Zhang, Jie; Bastian, Timothy

    2014-01-01

    This volume is a collection of research articles on the subject of the solar corona, and particularly, coronal magnetism. The book was motivated by the Workshop on Coronal Magnetism: Connecting Models to Data and the Corona to the Earth, which was held 21 - 23 May 2012 in Boulder, Colorado, USA. This workshop was attended by approximately 60 researchers. Articles from this meeting are contained in this topical issue, but the topical issue also contains contributions from researchers not present at the workshop. This volume is aimed at researchers and graduate students active in solar physics. Originally published in Solar Physics, Vol. 288, Issue 2, 2013 and Vol. 289, Issue 8, 2014.

  11. Synthesis and Characterization of Mixed Iron-Manganese Oxide Nanoparticles and Their Application for Efficient Nickel Ion Removal from Aqueous Samples

    Science.gov (United States)

    Serra, Antonio; Monteduro, Anna Grazia; Padmanabhan, Sanosh Kunjalukkal; Licciulli, Antonio; Bonfrate, Valentina; Salvatore, Luca; Calcagnile, Lucio

    2017-01-01

    Mixed iron-manganese oxide nanoparticles, synthesized by a simple procedure, were used to remove nickel ion from aqueous solutions. Nanostructures, prepared by using different weight percents of manganese, were characterized by transmission electron microscopy, selected area diffraction, X-ray diffraction, Raman spectroscopy, and vibrating sample magnetometry. Adsorption/desorption isotherm curves demonstrated that manganese inclusions enhance the specific surface area three times and the pores volume ten times. This feature was crucial to decontaminate both aqueous samples and food extracts from nickel ion. Efficient removal of Ni2+ was highlighted by the well-known dimethylglyoxime test and by ICP-MS analysis and the possibility of regenerating the nanostructure was obtained by a washing treatment in disodium ethylenediaminetetraacetate solution. PMID:28804670

  12. Synthesis and Characterization of Mixed Iron-Manganese Oxide Nanoparticles and Their Application for Efficient Nickel Ion Removal from Aqueous Samples

    Directory of Open Access Journals (Sweden)

    Alessandro Buccolieri

    2017-01-01

    Full Text Available Mixed iron-manganese oxide nanoparticles, synthesized by a simple procedure, were used to remove nickel ion from aqueous solutions. Nanostructures, prepared by using different weight percents of manganese, were characterized by transmission electron microscopy, selected area diffraction, X-ray diffraction, Raman spectroscopy, and vibrating sample magnetometry. Adsorption/desorption isotherm curves demonstrated that manganese inclusions enhance the specific surface area three times and the pores volume ten times. This feature was crucial to decontaminate both aqueous samples and food extracts from nickel ion. Efficient removal of Ni2+ was highlighted by the well-known dimethylglyoxime test and by ICP-MS analysis and the possibility of regenerating the nanostructure was obtained by a washing treatment in disodium ethylenediaminetetraacetate solution.

  13. Evidence towards improved estimation of respiratory muscle effort from diaphragm mechanomyographic signals with cardiac vibration interference using sample entropy with fixed tolerance values.

    Directory of Open Access Journals (Sweden)

    Leonardo Sarlabous

    Full Text Available The analysis of amplitude parameters of the diaphragm mechanomyographic (MMGdi signal is a non-invasive technique to assess respiratory muscle effort and to detect and quantify the severity of respiratory muscle weakness. The amplitude of the MMGdi signal is usually evaluated using the average rectified value or the root mean square of the signal. However, these estimations are greatly affected by the presence of cardiac vibration or mechanocardiographic (MCG noise. In this study, we present a method for improving the estimation of the respiratory muscle effort from MMGdi signals that is robust to the presence of MCG. This method is based on the calculation of the sample entropy using fixed tolerance values (fSampEn, that is, with tolerance values that are not normalized by the local standard deviation of the window analyzed. The behavior of the fSampEn parameter was tested in synthesized mechanomyographic signals, with different ratios between the amplitude of the MCG and clean mechanomyographic components. As an example of application of this technique, the use of fSampEn was explored also in recorded MMGdi signals, with different inspiratory loads. The results with both synthetic and recorded signals indicate that the entropy parameter is less affected by the MCG noise, especially at low signal-to-noise ratios. Therefore, we believe that the proposed fSampEn parameter could improve estimates of respiratory muscle effort from MMGdi signals with the presence of MCG interference.

  14. Monitoring vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Tiryaki, B. [Hacettepe University (Turkey). Dept. of Mining Engineering

    2003-12-01

    The paper examines the prediction and optimisation of machine vibrations in longwall shearers. Underground studies were carried out at the Middle Anatolian Lignite Mine, between 1993 and 1997. Several shearer drums with different pick lacing arrangements were designed and tested on double-ended ranging longwall shearers employed at the mine. A computer program called the Vibration Analysis Program (VAP) was developed for analysing machine vibrations in longwall shearers. Shearer drums that were tested underground, as well as some provided by leading manufacturers, were analyzed using these programs. The results of the experiments and computer analyses are given in the article. 4 refs., 9 figs.

  15. Chiral cavity ring down polarimetry: Chirality and magnetometry measurements using signal reversals.

    Science.gov (United States)

    Bougas, Lykourgos; Sofikitis, Dimitris; Katsoprinakis, Georgios E; Spiliotis, Alexandros K; Tzallas, Paraskevas; Loppinet, Benoit; Rakitzis, T Peter

    2015-09-14

    We present the theory and experimental details for chiral-cavity-ring-down polarimetry and magnetometry, based on ring cavities supporting counterpropagating laser beams. The optical-rotation symmetry is broken by the presence of both chiral and Faraday birefringence, giving rise to signal reversals which allow rapid background subtractions. We present the measurement of the specific rotation at 800 nm of vapors of α-pinene, 2-butanol, and α-phellandrene, the measurement of optical rotation of sucrose solutions in a flow cell, the measurement of the Verdet constant of fused silica, and measurements and theoretical treatment of evanescent-wave optical rotation at a prism surface. Therefore, these signal-enhancing and signal-reversing methods open the way for ultrasensitive polarimetry measurements in gases, liquids and solids, and at surfaces.

  16. Magnetic behavior of NiO nanoparticles determined by SQUID magnetometry

    Science.gov (United States)

    Shahzad, Farrakh; Nadeem, Kashif; Weber, Julia; Krenn, Heinz; Knoll, Peter

    2017-08-01

    NiO nanoparticles (4 nm-80 nm diameter) are investigated by SQUID magnetometry. Hysteresis loops at various temperatures and susceptibility versus temperature measurements using field-cooled/zero-field cooled protocols at various magnetic fields are performed. The measurements give evidence for a strong increase of magnetic moments with decreasing size of NiO nanoparticles. From the dependence of the magnetic moment on temperature and external field, blocked superparamagnetism is observed superimposed to the core antiferromagnetism of NiO-particles. A quantitative estimate demonstrates that uncompensated surface spins contribute to a ferromagnetic-like hysteresis modelled by a broad distribution of anisotropy fields at the surface induced by the antiferromagnetic core.

  17. Vibrational Diver

    Science.gov (United States)

    Kozlov, Victor; Ivanova, Alevtina; Schipitsyn, Vitalii; Stambouli, Moncef

    2014-10-01

    The paper is concerned with dynamics of light solid in cavity with liquid subjected to rotational vibration in the external force field. New vibrational phenomenon - diving of a light cylinder to the cavity bottom is found. The experimental investigation of a horizontal annulus with a partition has shown that under vibration a light body situated in the upper part of the layer is displaced in a threshold manner some distance away from the boundary. In this case the body executes symmetric tangential oscillations. An increase of the vibration intensity leads to a tangential displacement of the body near the external boundary. This displacement is caused by the tangential component of the vibrational lift force, which appears as soon as the oscillations lose symmetry. In this case the trajectory of the body oscillatory motion has the form of a loop. The tangential lift force makes stable the position of the body on the inclined section of the layer and even in its lower part. A theoretical interpretation has been proposed, which explains stabilization of a quasi-equilibrium state of a light body near the cavity bottom in the framework of vibrational hydromechanics.

  18. Sampling

    CERN Document Server

    Thompson, Steven K

    2012-01-01

    Praise for the Second Edition "This book has never had a competitor. It is the only book that takes a broad approach to sampling . . . any good personal statistics library should include a copy of this book." —Technometrics "Well-written . . . an excellent book on an important subject. Highly recommended." —Choice "An ideal reference for scientific researchers and other professionals who use sampling." —Zentralblatt Math Features new developments in the field combined with all aspects of obtaining, interpreting, and using sample data Sampling provides an up-to-date treat

  19. Effects of rock wool on the lungs evaluated by magnetometry and biopersistence test

    Directory of Open Access Journals (Sweden)

    Tomita Masayuki

    2009-03-01

    Full Text Available Abstract Background Asbestos has been reported to cause pulmonary fibrosis, and its use has been banned all over the world. The related industries are facing an urgent need to develop a safer fibrous substance. Rock wool (RW, a kind of asbestos substitute, is widely used in the construction industry. In order to evaluate the safety of RW, we performed a nose-only inhalation exposure study in rats. After one-month observation period, the potential of RW fibers to cause pulmonary toxicity was evaluated based on lung magnetometry findings, pulmonary biopersistence, and pneumopathology. Methods Using the nose-only inhalation exposure system, 6 male Fischer 344 rats (6 to 10 weeks old were exposed to RW fibers at a target fiber concentration of 100 fibers/cm3 (length [L] > 20 μm for 6 hours daily, for 5 consecutive days. As a magnetometric indicator, 3 mg of triiron tetraoxide suspended in 0.2 mL of physiological saline was intratracheally administered after RW exposure to these rats and 6 unexposed rats (controls. During one second magnetization in 50 mT external magnetic field, all magnetic particles were aligned, and immediately afterwards the strength of their remanent magnetic field in the rat lungs was measured in both groups. Magnetization and measurement of the decay (relaxation of this remanent magnetic field was performed over 40 minutes on 1, 3, 14, and 28 days after RW exposure, and reflected cytoskeleton dependent intracellular transport within macrophages in the lung. Similarly, 24 and 12 male Fisher 344-rats were used for biopersistence test and pathologic evaluation, respectively. Results In the lung magnetometric evaluation, biopersistence test and pathological evaluation, the arithmetic mean value of the total fiber concentration was 650.2, 344.7 and 390.7 fibers/cm3, respectively, and 156.6, 93.1 and 95.0 fibers/cm3 for fibers with L > 20 μm, respectively. The lung magnetometric evaluation revealed that impaired relaxation

  20. A combined magnetometry and gravity study across Zagros orogeny in Iran

    Science.gov (United States)

    Abedi, Maysam; Oskooi, Behrooz

    2015-11-01

    In this work, the structural geology and the tectonic conditions of the Zagros orogeny along the route of Qom to Kermanshah cities were investigated using the combined geophysical methods of the airborne magnetometry and the ground-based gravity data. Airborne magnetometry data of Iran with a line space of survey, 7.5 km, were used to model the magnetic susceptibility property along the route. At first, the airborne magnetic data were stably 500-m downward continued to the ground surface in order to enhance minor changes of the Earth's magnetic field over the studied region. Afterward, 3D inverse modeling of the magnetic data was implemented to the downward continued data, and subsequently the section of magnetic susceptibility variation along the desired route was extracted and imaged at depth. The acquired model could appropriately predict the observed magnetic data, showing low misfit values between the observation and the predicted data. The analytic signal filter was applied to the reduced-to-pole (RTP) magnetic data leading to the determination of the active and probable hidden faults in the structural zones of the Zagros, such as Sanandaj-Sirjan, Central Domain (CD) and Urumieh-Dokhtar based upon the generated peaks along the profile of analytic signal filter. In addition, the density variations of the subsurface geological layers were determined by 3D inverting of the ground-based gravity data over the whole study area, and extracting this property along the route. The joint models of magnetic susceptibility and density variation could appropriately localize the traces of faults along with the geologically and tectonically structural boundaries in the region. The locations of faults correspond well to the variation of geophysical parameters on the inverted sections. Probable direction, slope and extension at depth of these faults were also determined on the sections, indicating a high tectonized zone of the Sanandaj-Sirjan Zone (SSZ) parallel to the zone of

  1. Atomic Magnetometry in the Lab, in the Field, and in the Sky

    Science.gov (United States)

    Patton, B.; Versolato, O.; Hovde, C.; Rochester, S.; Higbie, J.; Budker, D.

    2012-12-01

    Atomic magnetometers [1] have played an important role in geophysical research ever since their advent more than fifty years ago. They have been used in near-surface magnetic surveys, aboard ionospheric sounding rockets, and have been critical in satellite missions dedicated to precise geophysical field mapping [2]. Over the past decade, renewed interest in atomic magnetometers has led to dramatically improved sensitivity in laboratory devices. The best alkali-vapor magnetometers, operating in magnetically shielded low-field environments, can now achieve sensitivities better than 1 femtotesla in a one-second measurement [3]. The precision of atomic magnetometers operating at Earth's field, on the other hand, has lagged in comparison. We will review recent efforts to achieve better sensitivity and accuracy in all-optical alkali-vapor magnetometers operating in geophysical field ranges. Advances in laser technology, antirelaxation vapor-cell coatings [4], and optical pumping techniques have resulted in better fundamental precision and dramatically reduced systematic error in these devices. The result is a new generation of compact, low-cost, and low-power sensors which are well suited for geophysical research. In addition to these developments, we will also discuss the potential for fully remote atom-based magnetic measurements [5]. This includes a proposed scheme to measure the magnetic field within the mesospheric sodium layer using existing laser guide star technology [6]. This technique would allow magnetic surveying at length and time scales heretofore inaccessible, and would yield data relevant to magnetic anomaly mapping, ionospheric physics, ocean circulation models, and lithospheric magnetization studies. [1] Budker, D., and M. Romalis (2007), Optical magnetometry, Nat. Phys., 3(4), 227-234. [2] Ravat, D., et al. (1995), Global vector and scalar Magsat magnetic anomaly maps, J. Geophys. Res.-Solid Earth, 100(B10), 20111-20136. [3] Dang, H. B., et al. (2010

  2. Vibrating minds

    CERN Document Server

    2009-01-01

    Ed Witten is one of the leading scientists in the field of string theory, the theory that describes elementary particles as vibrating strings. This week he leaves CERN after having spent a few months here on sabbatical. His wish is that the LHC will unveil supersymmetry.

  3. Transport and torque magnetometry measurements on CeAuSb2

    Science.gov (United States)

    Zhao, Lishan; Yelland, Edward; Bruin, Jan; Sakai, Hide; Sheikin, Ilya; MacKenzie, Andrew

    2015-03-01

    The tetragonal crystal CeAuSb2 has a layered structure and orders antiferromagnetically at T ~ 6K. Under a c-axis magnetic field, the Neel temperature is gradually suppressed to zero at a possible field-tuned quantum critical point at about 6 T. Within this antiferromagnetic phase, between the QCP and about 2.8 T, there is an additional, novel phase. We report transport measurements on pure single crystals of CeAuSb2, in fields of up to 35 T and from room temperature down to 100 mK. We also report torque magnetometry measurements. Unlike a recent report, we find single, sharp transitions into the novel phase. We discuss the nature of the novel phase. The work presented is supported by TOPNES(Topological Protection and Non-Equilibrium States in Strongly Correlated Electron Systems research programme), the Engineering and Physical Sciences Research Council (EPSRC, UK) and Max Planck Institute for Chemical Physics of Solids(Dresden, Germany) etc.

  4. Direct observation of temperature-driven magnetic symmetry transitions by vectorial resolved MOKE magnetometry

    Science.gov (United States)

    Cuñado, Jose Luis F.; Pedrosa, Javier; Ajejas, Fernando; Perna, Paolo; Miranda, Rodolfo; Camarero, Julio

    2017-10-01

    Angle- and temperature-dependent vectorial magnetometry measurements are necessary to disentangle the effective magnetic symmetry in magnetic nanostructures. Here we present a detailed study on an Fe(1 0 0) thin film system with competing collinear biaxial (four-fold symmetry) and uniaxial (two-fold) magnetic anisotropies, carried out with our recently developed full angular/broad temperature range/vectorial-resolved magneto-optical Kerr effect magnetometer, named TRISTAN. The data give direct views on the angular and temperature dependence of the magnetization reversal pathways, from which characteristic axes, remanences, critical fields, domain wall types, and effective magnetic symmetry are obtained. In particular, although the remanence shows four-fold angular symmetry for all investigated temperatures (15 K-400 K), the critical fields show strong temperature and angular dependencies and the reversal mechanism changes for specific angles at a given (angle-dependent) critical temperature, showing signatures of an additional collinear two-fold symmetry. This symmetry-breaking is more relevant as temperature increases to room temperature. It originates from the competition between two anisotropy contributions with different symmetry and temperature evolution. The results highlight the importance of combining temperature and angular studies, and the need to look at different magnetic parameters to unravel the underlying magnetic symmetries and temperature evolutions of the symmetry-breaking effects in magnetic nanostructures.

  5. Volumetric localization of epileptic activities in tuberous sclerosis using synthetic aperture magnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Zheng [Hospital for Sick Children, Research Institute, Toronto (Canada); Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Xiang, Jing [Hospital for Sick Children, Research Institute, Toronto (Canada); Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Holowka, Stephanie; Chuang, Sylvester [Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Hunjan, Amrita; Sharma, Rohit; Otsubo, Hiroshi [Hospital for Sick Children, Division of Neurology, Toronto (Canada)

    2006-01-01

    Magnetoencephalography (MEG) is a novel noninvasive technique for localizing epileptic zones. Tuberous sclerosis complex (TSC) is often associated with medically refractory epilepsy with multiple epileptic zones. Surgical treatment of TSC requires accurate localization of epileptogenic tubers. The objective of this study was to introduce a new MEG technique, synthetic aperture magnetometry (SAM), to volumetrically localize irritable zones and clarify the correlations between SAM, dipole modeling and anatomical tubers. Eight pediatric patients with TSC confirmed by clinical and neuroimaging findings were retrospectively studied. MEG data were recorded using a whole-cortex CTF OMEGA system. Sleep deprivation was employed to provoke epileptiform activity. Irritable zones were localized using both dipole modeling and SAM. MRI detected 42 tubers in the eight patients. Dipole modeling localized 28 irritable zones, and 19 out of the 28 zones were near tubers (19/42, 45%). SAM found 51 irritable zones, and 31 out of the 51 zones were near tubers (31/42, 74%). Among the 51 irritable zones determined by SAM, thirty-five zones were in 1-35 Hz, nine zones were in 35-60 Hz, and seven zones were in 60-120 Hz. The new method, SAM, yielded very plausible equivalent sources for patients who showed anatomical tubers on MRI. Compared to conventional dipole modeling, SAM appeared to offer increased detection of irritable zones and beneficial volumetric and frequency descriptions. (orig.)

  6. Optically trapped nanodiamonds with nitrogen-vacancy center spins for scanning magnetometry and thermometry

    Science.gov (United States)

    Aleman, Benjamin J.; Horowitz, Viva R.; Andrich, Paolo; Christle, David J.; Toyli, David M.; Cleland, Andrew N.; Awschalom, David D.

    2013-03-01

    Nanodiamonds with nitrogen-vacancy (NV) centers are a versatile sensing platform that combines the optically addressable atom-like properties of embedded NV centers, which are sensitive to electromagnetic fields and temperature, with the physical size and mobility necessary for nanometer-scale spatial resolution. We constructed an optical tweezers apparatus that accomplishes position control of nanodiamonds in solution within a microfluidic circuit and enables simultaneous optical measurement and microwave manipulation of the NV centers' ground-state spins. We observe nanodiamond fluorescence and trapping stability over many hours, and infer high d.c. magnetic field and temperature sensitivities from measured spin resonance spectra. Scanning the position of the trapped nanodiamonds enables us to map the magnetic field of current-carrying wires and magnetic nanostructures, and perform thermometry in liquid. This work provides an approach to three-dimensional spin-based scanning probe magnetometry and thermometry in fluids for applications in the biological and physical sciences. This work was supported by AFOSR and DARPA.

  7. Pump-Enhanced Continuous-Wave Magnetometry Using Nitrogen-Vacancy Ensembles

    Science.gov (United States)

    Ahmadi, Sepehr; El-Ella, Haitham A. R.; Hansen, Jørn O. B.; Huck, Alexander; Andersen, Ulrik L.

    2017-09-01

    Ensembles of nitrogen-vacancy centers in diamond are a highly promising platform for high-sensitivity magnetometry, whose efficacy is often based on efficiently generating and monitoring magnetic-field-dependent infrared fluorescence. Here, we report on an increased sensing efficiency with the use of a 532-nm resonant confocal cavity and a microwave resonator antenna for measuring the local magnetic noise density using the intrinsic nitrogen-vacancy concentration of a chemical-vapor deposited single-crystal diamond. We measure a near-shot-noise-limited magnetic noise floor of 200 pT /√{Hz } spanning a bandwidth up to 159 Hz, and an extracted sensitivity of approximately 3 nT /√{Hz } , with further enhancement limited by the noise floor of the lock-in amplifier and the laser damage threshold of the optical components. Exploration of the microwave and optical pump-rate parameter space demonstrates a linewidth-narrowing regime reached by virtue of using the optical cavity, allowing an enhanced sensitivity to be achieved, despite an unoptimized collection efficiency of low nitrogen-vacancy concentration of about 0.2 ppb.

  8. Towards an understanding of microstructure of patterned FePt dots by magnetometry using pulse fields

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Z.J., E-mail: yanzhj@lzu.edu.cn [VBL of Akita University, Gakuen Machi 1-1, Tegata, Akita 010-8502 (Japan); Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Takahashi, S.; Hasegawa, T.; Ishio, S. [VBL of Akita University, Gakuen Machi 1-1, Tegata, Akita 010-8502 (Japan); Kondo, Y.; Ariake, J. [Akita Research Institute of Advanced Technology (AIT), 4-21 Sanuki, Araya, Akita 010-1623 (Japan)

    2014-01-15

    FePt nanodot arrays are patterned and investigated by X-ray magnetic circular dichroism measurements and magneto-optic Kerr effect magnetometry combined with pulse magnetic fields. The experimental results on varied timescale of the applied field are analyzed by Sharrock's formula, showing the emergence of hard and soft magnetic FePt grains with distinct perpendicular anisotropy. While the hard grains in L1{sub 0}-phase can construct the FePt dots with intrinsic perpendicular anisotropy fields around 90 kOe, the exchange coupling between the hard and soft grains in other dots degrades the dot perpendicular coercivity and widens the array switching field distribution, in both the 100 and 30 nm dot arrays. The dot size dependence of the proportion of the hard dot in the array demonstrates that the soft grains originate from the FePt grains of L1{sub 0}-phase with large c-axis misaligning and of fcc phase inside the dots, and the ion etching effects are insignificant. - Highlights: • Patterned FePt dot arrays are studied by XMCD and MOKE with pulse fields. • Results on varied timescale of the applied field indicate the dot microstructure. • Hard magnetic grains are in the L1{sub 0}-phase with perpendicular cell c-axis. • Hard magnetic dots with PMA fields around 90 kOe are found in the 100 and 30 nm dots. • Exchange coupling between the hard and soft grains degrades the soft dot coercivity.

  9. Weak Ferromagnetic Response of d Electrons and Antiferromagnetic Response of π Electrons in TPP[Mn(Pc)(CN)2]2 in Torque Magnetometry Experiments

    Science.gov (United States)

    Torizuka, Kiyoshi; Uwatoko, Yoshiya; Matsuda, Masaki; Yoshida, Gosuke; Kimata, Motoi; Tajima, Hiroyuki

    2017-11-01

    We have investigated the magnetic properties of TPP[Mn(Pc)(CN)2]2 by the cantilever magnetometry technique. This technique enables us to extract information on the magnetism even if the sample is very small (1 µg). The torque curve measured when the magnetic field (≤7 T) is rotated in a plane that includes the c-axis shows a signature that is characteristic of weak ferromagnetism. The electron responsible for this behavior should be the d electron of the Mn3+ ion. On the other hand, when the field is rotated in the ab-plane, the torque curve exhibits an antiferromagnetic signature. The electron responsible for this behavior should be the π electron. Taking the susceptibility data into account, we have proposed two models of the spin configuration for d electrons: canted antiferromagnetism, and the field-induced ferromagnetic alignment. We have pointed out that even in the canted antiferromagnetic case, the torque curve is the same as that in the ferromagnetic case if the anisotropy energy is very small. These models do not contradict the experimental observation that magnetoresistance is hardly seen in TPP[Mn(Pc)(CN)2]2 if the interaction between π and d electrons is weak.

  10. Theory of vibration protection

    CERN Document Server

    Karnovsky, Igor A

    2016-01-01

    This text is an advancement of the theory of vibration protection of mechanical systems with lumped and distributed parameters. The book offers various concepts and methods of solving vibration protection problems, discusses the advantages and disadvantages of different methods, and the fields of their effective applications. Fundamental approaches of vibration protection, which are considered in this book, are the passive, parametric and optimal active vibration protection. The passive vibration protection is based on vibration isolation, vibration damping and dynamic absorbers. Parametric vibration protection theory is based on the Shchipanov-Luzin invariance principle. Optimal active vibration protection theory is based on the Pontryagin principle and the Krein moment method. The book also contains special topics such as suppression of vibrations at the source of their occurrence and the harmful influence of vibrations on humans. Numerous examples, which illustrate the theoretical ideas of each chapter, ar...

  11. Integrated evaluation of the geology, aero gamma spectrometry and aero magnetometry of the Sul-Riograndense Shield, southernmost Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Leo A.; Savian, Jairo F., E-mail: leo.hartmann@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Instituto de Geociencias; Lopes, William R. [Servico Geologico do Brasil (CPRM), Porto Alegre, RS (Brazil). Gerencia de Geologia e Mineracao

    2016-03-15

    An integrated evaluation of geology, aero gamma spectrometry and aero magnetometry of the Sul-Riograndense Shield is permitted by the advanced stage of understanding of the geology and geochronology of the southern Brazilian Shield and a 2010 airborne geophysical survey. Gamma rays are registered from the rocks near the surface and thus describe the distribution of major units in the shield, such as the Pelotas batholith, the juvenile São Gabriel terrane, the granulite-amphibolite facies Taquarembo terrane and the numerous granite intrusions in the foreland. Major structures are also observed, e.g., the Dorsal de Cangucu shear. Magnetic signals register near surface crustal compositions (analytic signal) and total crust composition (total magnetic signal), so their variation as measured indicates either shallow or whole crustal structures. The Cacapava shear is outstanding on the images as is the magnetic low along the N-S central portion of the shield. These integrated observations lead to the deepening of the understanding of the largest and even detailed structures of the Sul-Riograndense Shield, some to be correlated to field geology in future studies. Most significant is the presence of different provinces and their limits depending on the method used for data acquisition - geology, aero gamma spectrometry or aero magnetometry. (author)

  12. Lattice Vibrations in Chlorobenzenes:

    DEFF Research Database (Denmark)

    Reynolds, P. A.; Kjems, Jørgen; White, J. W.

    1974-01-01

    Lattice vibrational dispersion curves for the ``intermolecular'' modes in the triclinic, one molecule per unit cell β phase of p‐C6D4Cl2 and p‐C6H4Cl2 have been obtained by inelastic neutron scattering. The deuterated sample was investigated at 295 and at 90°K and a linear extrapolation to 0°K...... was applied in order to correct for anharmonic effects. Calculations based on the atom‐atom model for van der Waals' interaction and on general potential parameters for the aromatic compounds agree reasonably well with the experimental observations. There is no substantial improvement in fit obtained either...

  13. Preparation of magnetic molecularly imprinted polymers by atom transfer radical polymerization for the rapid extraction of avermectin from fish samples.

    Science.gov (United States)

    You, Xiaoxiao; Gao, Lei; Qin, Dongli; Chen, Ligang

    2017-01-01

    A novel and highly efficient approach to obtain magnetic molecularly imprinted polymers is described to detect avermectin in fish samples. The magnetic molecularly imprinted polymers were synthesized by surface imprinting polymerization using magnetic multiwalled carbon nanotubes as the support materials, atom transfer radical polymerization as the polymerization method, avermectin as template, acrylamide as functional monomer, and ethylene glycol dimethacrylate as crosslinker. The characteristics of the magnetic molecularly imprinted polymers were assessed by using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometry, X-ray diffraction, and thermogravimetric analysis. The binding characteristics of magnetic molecularly imprinted polymers were researched through isothermal adsorption experiment, kinetics adsorption experiment, and the selectivity experiment. Coupled with ultra high performance liquid chromatography and tandem mass spectrometry, the extraction conditions of the magnetic molecularly imprinted polymers as adsorbents for avermectin were investigated in detail. The recovery of avermectin was 84.2-97.0%, and the limit of detection was 0.075 μg/kg. Relative standard deviations of intra- and inter-day precisions were in the range of 1.7-2.9% and 3.4-5.6%, respectively. The results demonstrated that the extraction method not only has high selectivity and accuracy, but also is convenient for the determination of avermectin in fish samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Model Predictive Vibration Control Efficient Constrained MPC Vibration Control for Lightly Damped Mechanical Structures

    CERN Document Server

    Takács, Gergely

    2012-01-01

    Real-time model predictive controller (MPC) implementation in active vibration control (AVC) is often rendered difficult by fast sampling speeds and extensive actuator-deformation asymmetry. If the control of lightly damped mechanical structures is assumed, the region of attraction containing the set of allowable initial conditions requires a large prediction horizon, making the already computationally demanding on-line process even more complex. Model Predictive Vibration Control provides insight into the predictive control of lightly damped vibrating structures by exploring computationally efficient algorithms which are capable of low frequency vibration control with guaranteed stability and constraint feasibility. In addition to a theoretical primer on active vibration damping and model predictive control, Model Predictive Vibration Control provides a guide through the necessary steps in understanding the founding ideas of predictive control applied in AVC such as: ·         the implementation of ...

  15. Tunable Passive Vibration Suppressor

    Science.gov (United States)

    Boechler, Nicholas (Inventor); Dillon, Robert Peter (Inventor); Daraio, Chiara (Inventor); Davis, Gregory L. (Inventor); Shapiro, Andrew A. (Inventor); Borgonia, John Paul C. (Inventor); Kahn, Daniel Louis (Inventor)

    2016-01-01

    An apparatus and method for vibration suppression using a granular particle chain. The granular particle chain is statically compressed and the end particles of the chain are attached to a payload and vibration source. The properties of the granular particles along with the amount of static compression are chosen to provide desired filtering of vibrations.

  16. Vibrations and Eigenvalues

    Indian Academy of Sciences (India)

    We make music by causing strings, membranes, or air columns to vibrate. Engineers design safe structures by control- ling vibrations. I will describe to you a very simple vibrating system and the mathematics needed to analyse it. The ideas were born in the work of Joseph-Louis Lagrange (1736–1813), and I begin by quot-.

  17. Preparation and characterisation of magnetic nanostructured samples for inelastic neutron scattering experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzpaintner, Wolfgang

    2010-06-22

    Recent advances in thin-film structuring techniques have generated significant interest in the dynamics of spin waves in magnetic nanostructures and the possible use of inelastic neutron scattering (INS) for their investigation. This thesis describes the design and implementation, at GKSS Research Centre, of equipment for preparation of large and laterally submicron and nanometre structured magnetic samples for such future INS experiments. After a brief resume on spin waves in nanostructures, the development work on new purpose-designed equipment, including high vacuum (HV) argon ion beam milling and ultra high vacuum (UHV) e-beam evaporation setups, is described. Ni nanodot as well as Ni and novel Gd nanowire samples were prepared using combinations of sputter deposition, laser interference lithography, argon ion beam milling, e-beam evaporation and self organisation techniques. With reference to sample preparation, epitaxial growth studies for Ni on Si(100) substrate were performed, resulting in the development of a new deposition process, which by thermal tuning allows for the direct epitaxial growth of Ni on Si with unprecedented crystalline quality. The results of various characterisation experiments on the prepared nanostructured samples, including Scanning Electron Microscopy (SEM), microprobe analysis, Atomic and Magnetic Force Microscopy (AFM/MFM), Vibrating Sample Magnetometry (VSM), X-ray Diffraction (XRD) and Reflectivity (XRR), unpolarised and Polarised Neutron Scattering (PNR) and off-specular scattering by X-rays and neutrons using rocking scans and Time-Of-Flight Grazing Incidence Small Angle Neutron Scattering (TOF-GISANS), together with various analysis procedures such as Distorted-Wave Born Approximation (DWBA), are reported. The analysis of a Gd nanowire sample by TOF-GISANS led to a novel evaluation technique which in comparison with single wavelength methods allows portions of reciprocal space to be scanned without changing the angle of

  18. Vibration analysis of cryocoolers

    Science.gov (United States)

    Tomaru, Takayuki; Suzuki, Toshikazu; Haruyama, Tomiyoshi; Shintomi, Takakazu; Yamamoto, Akira; Koyama, Tomohiro; Li, Rui

    2004-05-01

    The vibrations of Gifford-McMahon (GM) and pulse-tube (PT) cryocoolers were measured and analyzed. The vibrations of the cold-stage and cold-head were measured separately to investigate their vibration mechanisms. The measurements were performed while maintaining the thermal conditions of the cryocoolers at a steady state. We found that the vibration of the cold-head for the 4 K PT cryocooler was two orders of magnitude smaller than that of the 4 K GM cryocooler. On the other hand, the vibration of the cold-stages for both cryocoolers was of the same order of magnitude. From a spectral analysis of the vibrations and a simulation, we concluded that the vibration of the cold-stage is caused by an elastic deformation of the pulse tubes (or cylinders) due to the pressure oscillation of the working gas.

  19. Vibration analysis of cryocoolers

    Energy Technology Data Exchange (ETDEWEB)

    Tomaru, Takayuki; Suzuki, Toshikazu; Haruyama, Tomiyoshi; Shintomi, Takakazu; Yamamoto, Akira [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Koyama, Tomohiro; Rui Li [Sumitomo Heavy Industries Ltd., Tokyo (Japan)

    2004-05-01

    The vibrations of Gifford-McMahon (GM) and pulse-tube (PT) cryocoolers were measured and analyzed. The vibrations of the cold-stage and cold-head were measured separately to investigate their vibration mechanisms. The measurements were performed while maintaining the thermal conditions of the cryocoolers at a steady state. We found that the vibration of the cold-head for the 4 K PT cryocooler was two orders of magnitude smaller than that of the 4 K GM cryocooler. On the other hand, the vibration of the cold-stages for both cryocoolers was of the same order of magnitude. From a spectral analysis of the vibrations and a simulation, we concluded that the vibration of the cold-stage is caused by an elastic deformation of the pulse tubes (or cylinders) due to the pressure oscillation of the working gas. (Author)

  20. Vibration of hydraulic machinery

    CERN Document Server

    Wu, Yulin; Liu, Shuhong; Dou, Hua-Shu; Qian, Zhongdong

    2013-01-01

    Vibration of Hydraulic Machinery deals with the vibration problem which has significant influence on the safety and reliable operation of hydraulic machinery. It provides new achievements and the latest developments in these areas, even in the basic areas of this subject. The present book covers the fundamentals of mechanical vibration and rotordynamics as well as their main numerical models and analysis methods for the vibration prediction. The mechanical and hydraulic excitations to the vibration are analyzed, and the pressure fluctuations induced by the unsteady turbulent flow is predicted in order to obtain the unsteady loads. This book also discusses the loads, constraint conditions and the elastic and damping characters of the mechanical system, the structure dynamic analysis, the rotor dynamic analysis and the system instability of hydraulic machines, including the illustration of monitoring system for the instability and the vibration in hydraulic units. All the problems are necessary for vibration pr...

  1. A quantitative study of particle size effects in the magnetorelaxometry of magnetic nanoparticles using atomic magnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Dolgovskiy, V. [Physics Department, University of Fribourg, CH-1700 Fribourg (Switzerland); Lebedev, V., E-mail: victor.lebedev@unifr.ch [Physics Department, University of Fribourg, CH-1700 Fribourg (Switzerland); Colombo, S.; Weis, A. [Physics Department, University of Fribourg, CH-1700 Fribourg (Switzerland); Michen, B.; Ackermann-Hirschi, L. [Adolphe Merkle Institute, University of Fribourg, CH-1700 Fribourg (Switzerland); Petri-Fink, A. [Adolphe Merkle Institute, University of Fribourg, CH-1700 Fribourg (Switzerland); Chemistry Department, University of Fribourg, CH-1700 Fribourg (Switzerland)

    2015-04-01

    The discrimination of immobilised superparamagnetic iron oxide nanoparticles (SPIONs) against SPIONs in fluid environments via their magnetic relaxation behaviour is a powerful tool for bio-medical imaging. Here we demonstrate that a gradiometer of laser-pumped atomic magnetometers can be used to record accurate time series of the relaxing magnetic field produced by pre-polarised SPIONs. We have investigated dry in vitro maghemite nanoparticle samples with different size distributions (average radii ranging from 14 to 21 nm) and analysed their relaxation using the Néel–Brown formalism. Fitting our model function to the magnetorelaxation (MRX) data allows us to extract the anisotropy constant K and the saturation magnetisation M{sub S} of each sample. While the latter was found not to depend on the particle size, we observe that K is inversely proportional to the (time- and size-) averaged volume of the magnetised particle fraction. We have identified the range of SPION sizes that are best suited for MRX detection considering our specific experimental conditions and sample preparation technique. - Highlights: • We studied magnetorelaxation of magnetic nanoparticles using atomic magnetometers. • We show that atomic magnetometers yield high precision MRX data. • The observed magnetorelaxation is well described by the moment superposition model. • Model fits allow extraction of nanoparticle material parameters of six samples. • All samples exhibit an unexpected size-dependent anisotropy constant.

  2. Polydopamine-coated magnetic molecularly imprinted polymer for the selective solid-phase extraction of cinnamic acid, ferulic acid and caffeic acid from radix scrophulariae sample.

    Science.gov (United States)

    Yin, Yuli; Yan, Liang; Zhang, Zhaohui; Wang, Jing; Luo, Ningjing

    2016-04-01

    We describe novel cinnamic acid polydopamine-coated magnetic imprinted polymers for the simultaneous selective extraction of cinnamic acid, ferulic acid and caffeic acid from radix scrophulariae sample. The novel magnetic imprinted polymers were synthesized by surface imprinting polymerization using magnetic multi-walled carbon nanotubes as the support material, cinnamic acid as the template and dopamine as the functional monomer. The magnetic imprinted polymers were characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The results revealed that the magnetic imprinted polymers had outstanding magnetic properties, high adsorption capacity, selectivity and fast kinetic binding toward cinnamic acid, ferulic acid and caffeic acid. Coupled with high-performance liquid chromatography, the extraction conditions of the magnetic imprinted polymers as a magnetic solid-phase extraction sorbent were investigated in detail. The proposed imprinted magnetic solid phase extraction procedure has been used for the purification and enrichment of cinnamic acid, ferulic acid and caffeic acid successfully from radix scrophulariae extraction sample with recoveries of 92.4-115.0% for cinnamic acid, 89.4-103.0% for ferulic acid and 86.6-96.0% for caffeic acid. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. M(H) dependence and size distribution of SPIONs measured by atomic magnetometry

    CERN Document Server

    Colombo, Simone; Grujic, Zoran D; Dolgovskiy, Vladimir; Weis, Antoine

    2016-01-01

    We demonstrate that the quasistatic recording of the magnetic excitation function M(H) of superparamagnetic iron oxide magnetic nanoparticle (SPION) suspensions by an atomic magnetometer allows a precise determination of the sample's iron mass content mFe and the particle size distribution.

  4. High-speed optical measurement for the drumhead vibration

    Science.gov (United States)

    Zhang, Qican; Su, Xianyu

    2005-04-01

    In this paper, a high-speed optical measurement for the vibrating drumhead is presented and verified by experiment. A projected sinusoidal fringe pattern on the measured drumhead is dynamically deformed with the vibration of the membrane and grabbed by a high-speed camera. The shape deformation of the drumhead at each sampling instant can be recovered from this sequence of obtained fringe patterns. The vibration of the membrane of a Chinese drum has been measured with a high speed sampling rate (1,000 fps) and a standard deviation (0.075 mm). The restored vibration of the drumhead is also presented in an animation.

  5. Dynamical response of vibrating ferromagnets

    CERN Document Server

    Gaganidze, E; Ziese, M

    2000-01-01

    The resonance frequency of vibrating ferromagnetic reeds in a homogeneous magnetic field can be substantially modified by intrinsic and extrinsic field-related contributions. Searching for the physical reasons of the field-induced resonance frequency change and to study the influence of the spin glass state on it, we have measured the low-temperature magnetoelastic behavior and the dynamical response of vibrating amorphous and polycrystalline ferromagnetic ribbons. We show that the magnetoelastic properties depend strongly on the direction of the applied magnetic field. The influence of the re-entrant spin glass transition on these properties is discussed. We present clear experimental evidence that for applied fields perpendicular to the main area of the samples the behavior of ferromagnetic reeds is rather independent of the material composition and magnetic state, exhibiting a large decrease of the resonance frequency. This effect can be very well explained with a model based on the dynamical response of t...

  6. Model Indepedent Vibration Control

    OpenAIRE

    Yuan, Jing

    2010-01-01

    A NMIFC system is proposed for broadband vibration control. It has two important features. Feature F1 is that the NMIFC is stable without introducing any invasive effects, such as probing signals or controller perturbations, into the vibration system; feature F2 is

  7. Vibration Theory, Vol. 3

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.

    The present textbook has been written based on previous lecture notes for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M. Sc. students in structural engineering. The present 4th edition of this textbook on linear stochastic vibration...

  8. Vibration Theory, Vol. 3

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.

    The present textbook has been written based on previous lecture notes for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M. Sc. students in structural engineering. The present 2nd edition of this textbook on linear stochastic vibration...

  9. Hydroelastic Vibrations of Ships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Folsø, Rasmus

    2002-01-01

    A formula for the necessary hull girder bending stiffness required to avoid serious springing vibrations is derived. The expression takes into account the zero crossing period of the waves, the ship speed and main dimensions. For whipping vibrations the probability of exceedance for the combined...

  10. Gearbox vibration diagnostic analyzer

    Science.gov (United States)

    1992-01-01

    This report describes the Gearbox Vibration Diagnostic Analyzer installed in the NASA Lewis Research Center's 500 HP Helicopter Transmission Test Stand to monitor gearbox testing. The vibration of the gearbox is analyzed using diagnostic algorithms to calculate a parameter indicating damaged components.

  11. Mechanical vibration and shock analysis, sinusoidal vibration

    CERN Document Server

    Lalanne, Christian

    2014-01-01

    Everything engineers need to know about mechanical vibration and shock...in one authoritative reference work! This fully updated and revised 3rd edition addresses the entire field of mechanical vibration and shock as one of the most important types of load and stress applied to structures, machines and components in the real world. Examples include everything from the regular and predictable loads applied to turbines, motors or helicopters by the spinning of their constituent parts to the ability of buildings to withstand damage from wind loads or explosions, and the need for cars to m

  12. Preparation of magnetic metal organic frameworks adsorbent modified with mercapto groups for the extraction and analysis of lead in food samples by flame atomic absorption spectrometry.

    Science.gov (United States)

    Wang, Yang; Chen, Huanhuan; Tang, Jie; Ye, Guiqin; Ge, Huali; Hu, Xiaoya

    2015-08-15

    A novel magnetic metal organic frameworks adsorbent modified with mercapto groups was synthesized and developed for extraction and spectrophotometric determination of trace lead. The adsorbent was characterized by Fourier transforms infrared spectrometer, X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry. The results indicated the adsorbents exhibited high adsorption capacities for lead due to the chelation mechanism between metal cations and mercapto groups. Meanwhile, the lead sorption onto the adsorbents could be easily separated from aqueous solution using a magnetic separation method. Under the optimal conditions, a linear calibration curve in the range from 1 to 20 μg L(-1) was achieved with an enrichment factor of 100. The limits of detection and quantitation for lead were found to be 0.29 and 0.97 μg L(-1), respectively. The developed method was successfully applied to the determination of trace amounts of lead in food samples and certified reference material with satisfactory results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Vibrations of rotating machinery

    CERN Document Server

    Matsushita, Osami; Kanki, Hiroshi; Kobayashi, Masao; Keogh, Patrick

    2017-01-01

    This book opens with an explanation of the vibrations of a single degree-of-freedom (dof) system for all beginners. Subsequently, vibration analysis of multi-dof systems is explained by modal analysis. Mode synthesis modeling is then introduced for system reduction, which aids understanding in a simplified manner of how complicated rotors behave. Rotor balancing techniques are offered for rigid and flexible rotors through several examples. Consideration of gyroscopic influences on the rotordynamics is then provided and vibration evaluation of a rotor-bearing system is emphasized in terms of forward and backward whirl rotor motions through eigenvalue (natural frequency and damping ratio) analysis. In addition to these rotordynamics concerning rotating shaft vibration measured in a stationary reference frame, blade vibrations are analyzed with Coriolis forces expressed in a rotating reference frame. Other phenomena that may be assessed in stationary and rotating reference frames include stability characteristic...

  14. Structural Stability and Vibration

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Pedersen, Pauli

    This book offers an integrated introduction to the topic of stability and vibration. Strikingly, it describes stability as a function of boundary conditions and eigenfrequency as a function of both boundary conditions and column force. Based on a post graduate course held by the author at the Uni......This book offers an integrated introduction to the topic of stability and vibration. Strikingly, it describes stability as a function of boundary conditions and eigenfrequency as a function of both boundary conditions and column force. Based on a post graduate course held by the author...... and their derivation, thus stimulating them to write interactive and dynamic programs to analyze instability and vibrational modes....

  15. Vibrational spectroscopy in the electron microscope.

    Science.gov (United States)

    Krivanek, Ondrej L; Lovejoy, Tracy C; Dellby, Niklas; Aoki, Toshihiro; Carpenter, R W; Rez, Peter; Soignard, Emmanuel; Zhu, Jiangtao; Batson, Philip E; Lagos, Maureen J; Egerton, Ray F; Crozier, Peter A

    2014-10-09

    Vibrational spectroscopies using infrared radiation, Raman scattering, neutrons, low-energy electrons and inelastic electron tunnelling are powerful techniques that can analyse bonding arrangements, identify chemical compounds and probe many other important properties of materials. The spatial resolution of these spectroscopies is typically one micrometre or more, although it can reach a few tens of nanometres or even a few ångströms when enhanced by the presence of a sharp metallic tip. If vibrational spectroscopy could be combined with the spatial resolution and flexibility of the transmission electron microscope, it would open up the study of vibrational modes in many different types of nanostructures. Unfortunately, the energy resolution of electron energy loss spectroscopy performed in the electron microscope has until now been too poor to allow such a combination. Recent developments that have improved the attainable energy resolution of electron energy loss spectroscopy in a scanning transmission electron microscope to around ten millielectronvolts now allow vibrational spectroscopy to be carried out in the electron microscope. Here we describe the innovations responsible for the progress, and present examples of applications in inorganic and organic materials, including the detection of hydrogen. We also demonstrate that the vibrational signal has both high- and low-spatial-resolution components, that the first component can be used to map vibrational features at nanometre-level resolution, and that the second component can be used for analysis carried out with the beam positioned just outside the sample--that is, for 'aloof' spectroscopy that largely avoids radiation damage.

  16. Core-shell polydopamine magnetic nanoparticles as sorbent in micro-dispersive solid-phase extraction for the determination of estrogenic compounds in water samples prior to high-performance liquid chromatography-mass spectrometry analysis.

    Science.gov (United States)

    Socas-Rodríguez, Bárbara; Hernández-Borges, Javier; Salazar, Pedro; Martín, Miriam; Rodríguez-Delgado, Miguel Ángel

    2015-06-05

    In this work, core-shell Fe3O4@poly(dopamine) magnetic nanoparticles (m-NPs) were prepared and characterized in our laboratory and applied as sorbents for the magnetic-micro solid phase extraction (m-μSPE) of twelve estrogenic compounds of interest (i.e. 17α-estradiol, 17β-estradiol, estrone, hexestrol, 17α-ethynylestradiol, diethylstibestrol, dienestrol, zearalenone, α-zearalanol, β-zearalanol, α-zearalenol and β-zearalenol) from different water samples. Separation, determination and quantification were achieved by high-performance liquid chromatography coupled to ion trap mass spectrometry with electrospray ionization. NPs@poly(dopamine) were synthesized by a chemical coprecipitation procedure and characterized by different surface characterization techniques (X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, transmission and scanning electron microscopy, infrared and Raman spectroscopy, vibrating sample magnetometry, microelectrophoresis and adsorption/desorption isotherms). Parameters affecting the extraction efficiency of m-μSPE (i.e. polymerization time, pH of the sample, extraction and elution conditions) were studied and optimized. The methodology was validated for Milli-Q, mineral, tap and wastewater using 2-methoxyestradiol as internal standard, obtaining recoveries ranging from 70 to 119% with relative standard deviation values lower than 20% and limits of quantification in the range 0.02-1.1 μg/L. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Vibration Analysis and the Accelerometer

    Science.gov (United States)

    Hammer, Paul

    2011-01-01

    Have you ever put your hand on an electric motor or motor-driven electric appliance and felt it vibrate? Ever wonder why it vibrates? What is there about the operation of the motor, or the object to which it is attached, that causes the vibrations? Is there anything "regular" about the vibrations, or are they the result of random causes? In this…

  18. Whole body vibration improves body mass, flexibility and strength in ...

    African Journals Online (AJOL)

    Whole body vibration improves body mass, flexibility and strength in previously sedentary adults. Abstract. Objectives. This study aimed to determine the effectiveness of whole body vibration (WBV) training for promoting health- related physical fitness in sedentary adults. Design. A non-randomised sampling technique was ...

  19. Vibrations and Stability

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    About this textbook An ideal text for students that ties together classical and modern topics of advanced vibration analysis in an interesting and lucid manner. It provides students with a background in elementary vibrations with the tools necessary for understanding and analyzing more complex...... dynamical phenomena that can be encountered in engineering and scientific practice. It progresses steadily from linear vibration theory over various levels of nonlinearity to bifurcation analysis, global dynamics and chaotic vibrations. It trains the student to analyze simple models, recognize nonlinear...... phenomena and work with advanced tools such as perturbation analysis and bifurcation analysis. Explaining theory in terms of relevant examples from real systems, this book is user-friendly and meets the increasing interest in non-linear dynamics in mechanical/structural engineering and applied mathematics...

  20. Cavity enhanced atomic magnetometry.

    Science.gov (United States)

    Crepaz, Herbert; Ley, Li Yuan; Dumke, Rainer

    2015-10-20

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations.

  1. Subpicotesla Diamond Magnetometry

    Directory of Open Access Journals (Sweden)

    Thomas Wolf

    2015-10-01

    Full Text Available Nitrogen-vacancy (NV defect centers in diamond are promising solid-state magnetometers. Single centers allow for high-spatial-resolution field imaging but are limited in their magnetic field sensitivity. Using defect-center ensembles, sensitivity can be scaled with sqrt[N] when N is the number of defects. In the present work, we use an ensemble of N∼10^{11} defect centers within an effective sensor volume of 8.5×10^{-4}  mm^{3} for sensing at room temperature. By carefully eliminating noise sources and using high-quality diamonds with large NV concentrations, we demonstrate, for such sensors, a sensitivity scaling as 1/sqrt[t], where t is the total measurement time. The associated photon-shot-noise-limited magnetic-field sensitivity for ac signals of f=20  kHz is 0.9  pT/sqrt[Hz]. For a total measurement time of 100 s, we reach a standard deviation of about 100 fT. Further improvements using decoupling sequences and material optimization could lead to fT/sqrt[Hz] sensitivity.

  2. Cavity enhanced atomic magnetometry

    CERN Document Server

    Crepaz, Herbert; Dumke, Rainer

    2015-01-01

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations.

  3. Mechanical Vibration Measurements on TTF Cryomodules

    CERN Document Server

    Bosotti, Angelo; Ferianis, Mario; Lange, Rolf; Pagani, Carlo; Paparella, Rocco; Pierini, Paolo; Sertore, Daniele

    2005-01-01

    Few of the TTF cryomodules have been equipped with Wire Position Monitors (WPM) for the on line monitoring of cold mass movements during cool-down, warm-up and operation. Each sensor can be used as a detector for mechanical vibrations of the cryostat. A Digital Receiver board is used to sample and analyze with high frequency resolution, the WPM picked up signals, looking to its amplitude modulation in the microphonic frequency range. Here we review and analyze the data and the vibration spectra taken during operation of the TTF cryomodules # 4 and #5.

  4. Hydrothermal synthesis of NiFe2O4 nano-particles: structural ...

    Indian Academy of Sciences (India)

    –H loop and M–T curve behaviours are investigated by vibrating sample magnetometry.The optical band gap energy is estimated from the UV–visible spectrum. In addition, the frequency dependence of dielectric properties is investigated.

  5. Enhanced adsorptive degradation of Congo red in aqueous solutions using polyaniline/Fe0 composite nanofibers

    CSIR Research Space (South Africa)

    Bhaumik, M

    2015-01-01

    Full Text Available -ray Photoelectron Spectroscopy (XPS) and Vibrating Sample Magnetometry (VSM). These CNFs exhibited enhanced performance relevant to the adsorptive degradation/decolourization of CR, compared to PANI NFs and Fe0 nanoparticle counterparts. Batch experiments with a...

  6. Fabrication of graphene/Fe3O4@polythiophene nanocomposite and its application in the magnetic solid-phase extraction of polycyclic aromatic hydrocarbons from environmental water samples.

    Science.gov (United States)

    Mehdinia, Ali; Khodaee, Nader; Jabbari, Ali

    2015-04-08

    Polythiophene (PT) was used as a surface modifier of graphene/Fe3O4 (G/Fe3O4) composite to increase merit of it, and also overcome some limitations and disadvantages of using G/Fe3O4 alone as solid phase extraction (SPE) sorbent. An in-situ chemical polymerization method was employed to prepare G/Fe3O4@PT nanocomposites. Application of this newly designed material in the magnetic SPE (MSPE) of polycyclic aromatic hydrocarbons (PAHs), as model analytes, in the environmental water samples was investigated. The characterization of the hybrid material was performed using transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray analysis, Fourier transform-infrared (FT-IR) spectroscopy and vibrating sample magnetometry. Seven important parameters, affecting the extraction efficiency of PAHs, including: amount of adsorbent, adsorption and desorption times, type and volume of the eluent solvent, initial sample volume and salt content of the sample were evaluated. The optimum extraction conditions were obtained as: 4 min for extraction time, 20 mg for sorbent amount, 100mL for initial sample volume, toluene as desorption solvent, 0.6 mL for desorption solvent volume, 6 min for desorption time and 30% (w/v) for NaCl concentration. Good performance data were obtained at the optimized conditions. Detection limits were in the range of 0.009-0.020 μg L(-1) in the real matrix. The calibration curves were linear over the concentration ranges from 0.03 to 80 μg L(-1) with correlation coefficients (R(2)) between 0.995 and 0.998 for all the analytes. Relative standard deviations were ranged from 4.3 to 6.3%. Appropriate recovery values, in the range of 83-107%, were also obtained for the real sample analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Characterization of pollen by vibrational spectroscopy.

    Science.gov (United States)

    Zimmermann, Boris

    2010-12-01

    Classification, discrimination, and biochemical assignment of vibrational spectra of pollen samples belonging to 43 different species of the order Pinales has been made using three different vibrational techniques. The comparative study of transmission (KBr pellet) and attenuated total reflection (ATR) Fourier transform infrared (FT-IR) and FT-Raman spectroscopies was based on substantial variability of pollen grain size, shape, and relative biochemical composition. Depending on the penetration depth of the probe light, vibrational techniques acquire predominant information either on pollen grain walls (FT-Raman and ATR-FT-IR) or intracellular material (transmission FT-IR). Compared with the other two methods, transmission FT-IR obtains more comprehensive information and as a result achieves superior spectral identification and discrimination of pollen. The results strongly indicate that biochemical similarities of pollen grains belonging to the same plant genus or family lead to similar features in corresponding vibrational spectra. The exploitation of that property in aerobiological monitoring was demonstrated by simple and rapid pollen identification based on relatively small spectral libraries, with the same (or better) taxonomic resolution as that provided by optical microscopy. Therefore, the clear correlation between vibrational spectra and pollen grain morphology, biochemistry, and taxonomy is obtained, while successful pollen identification illustrates the practicability of such an approach in environmental studies.

  8. Vibrational spectroscopy of resveratrol

    Science.gov (United States)

    Billes, Ferenc; Mohammed-Ziegler, Ildikó; Mikosch, Hans; Tyihák, Ernő

    2007-11-01

    In this article the authors deal with the experimental and theoretical interpretation of the vibrational spectra of trans-resveratrol (3,5,4'-trihydroxy- trans-stilbene) of diverse beneficial biological activity. Infrared and Raman spectra of the compound were recorded; density functional calculations were carried out resulting in the optimized geometry and several properties of the molecule. Based on the calculated force constants, a normal coordinate analysis yielded the character of the vibrational modes and the assignment of the measured spectral bands.

  9. Bumblebee vibration activated foraging

    OpenAIRE

    Su, Dan Kuan-Nien

    2009-01-01

    The ability use vibrational signals to activate nestmate foraging is found in the highly social bees, stingless bees and honey bees, and has been hypothesized to exist in the closely related, primitively eusocial bumble bees. We provide the first strong and direct evidence that this is correct. Inside the nest, bumble bee foragers produce brief bursts of vibration (foraging activation pulses) at 594.5 Hz for 63±26 ms (velocityRMS=0.46±0.02mm/s, forceRMS=0.8±0.2 mN. Production of these vibrati...

  10. Man-Induced Vibrations

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Hansen, Lars Pilegaard

    1994-01-01

    concerned with spectator-induced vertical vibrations on grandstands. The idea is to use impulse response analysis and base the load description on the load impulse. If the method is feasable, it could be used in connection with the formulation of requirements in building codes. During the last two decades...... work has been done on the measurement of the exact load functions and related reponse analysis. A recent work using a spectral description has been performed by Per-Erik Erikson and includes a good literature survey. Bachmann and Ammann give a good overview of vibrations caused by human activity. Other...

  11. Vibrations and waves

    CERN Document Server

    Kaliski, S

    2013-01-01

    This book gives a comprehensive overview of wave phenomena in different media with interacting mechanical, electromagnetic and other fields. Equations describing wave propagation in linear and non-linear elastic media are followed by equations of rheological models, models with internal rotational degrees of freedom and non-local interactions. Equations for coupled fields: thermal, elastic, electromagnetic, piezoelectric, and magneto-spin with adequate boundary conditions are also included. Together with its companion volume Vibrations and Waves. Part A: Vibrations this work provides a wealth

  12. Heterogeneous Dynamics of Coupled Vibrations

    NARCIS (Netherlands)

    Cringus, Dan; Jansen, Thomas I. C.; Pshenichnikov, Maxim S.; Schoenlein, RW; Corkum, P; DeSilvestri, S; Nelson, KA; Riedle, E

    2009-01-01

    Frequency-dependent dynamics of coupled stretch vibrations of a water molecule are revealed by 2D IR correlation spectroscopy. These are caused by non-Gaussian fluctuations of the environment around the individual OH stretch vibrations.

  13. Preparation and characterization of magnetic Wells-Dawson heteropoly acid nanoparticles for magnetic solid-phase extraction of aromatic amines in water samples.

    Science.gov (United States)

    Amiri, Amirhassan; Saadati-Moshtaghin, Hamid Reza; Zonoz, Farokhzad Mohammadi; Targhoo, Azadeh

    2017-02-03

    In this work, aminopropyl modified silica-coated magnetite nanoparticles with Wells-Dawson heteropoly acid (P2W17Fe@APSCMNPs) was first synthesized and underwent highly efficient magnetic solid-phase extraction (MSPE) of aromatic amines from aqueous samples. The resulted nanomaterials were characterized with different physicochemical techniques such as Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). Aniline, N,N-dimethylaniline, o-toluidine and 3-chloroaniline were selected as target compounds. The sample quantification was carried out using gas chromatography-flame ionization detector (GC-FID). Under optimal working conditions, the developed method showed good linearity (R>0.9912) in the range of 0.01-100ngmL(-1). The method displays detection limits (at an S/N ration of 3) in the range from 0.003 to 0.01ngmL(-1), and the limits of quantification (at an S/N ratio of 10) are between 0.01 and 0.04ngmL(-1). The enrichment factors (EFs) were in the range of 75-113. Relative standard deviations (RSDs) are 4.8-8.3%. The applicability of the developed method was examined by analyzing different water samples (river water, tap water, well water and wastewater) and the relative recovery values for the spiked water samples were found to be in the range of 90.7-99.8%. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Determination of fluoroquinolone antibiotics in environmental water samples based on magnetic molecularly imprinted polymer extraction followed by liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Chen Ligang; Zhang Xiaopan; Xu Yang [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, Jilin (China); Du Xiaobo; Sun Xin [College of Physics, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Sun Lei; Wang Hui; Zhao Qi; Yu Aimin; Zhang Hanqi [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, Jilin (China); Ding Lan, E-mail: dinglan@jlu.edu.cn [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, Jilin (China)

    2010-03-03

    A simple method based on magnetic separation for selective extraction of fluoroquinolones (FQs) from environmental water samples has been developed using magnetic molecularly imprinted polymer (MMIP) as sorbent. The MMIP has been prepared using ciprofloxacin as template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linking agent and Fe{sub 3}O{sub 4} magnetite as magnetic component. The polymer has been characterized by scanning electron microscopy, Fourier-transform infrared spectrometry and vibrating sample magnetometry. Various parameters affecting the extraction efficiency were evaluated in order to achieve optimal concentration and reduce non-specific interactions. The analytes desorbed from the polymers were determined by liquid chromatography-tandem mass spectrometry. The matrix effect was evaluated by using different washing solvents for removing interfering compounds from the MMIPs after sample loading. Under the optimal conditions, the linearity of the method obtained is in the range of 20-2000 ng L{sup -1}. The detection limits of FQs are in the range of 3.2-6.2 ng L{sup -1}. The relative standard deviations of intra- and inter-day tests ranging from 2.5 to 7.2% and from 3.6 to 9.1% are obtained. In all three spiked levels (20, 100 and 200 ng L{sup -1}), the recoveries of FQs are in the range of 76.3-94.2%. The proposed method was successfully applied to determine FQs including ciprofloxacin, enrofloxacin, lomefloxacin, levofloxacin, fleroxacin and sparfloxacin in different water samples, such as lake water, river water, primary and final sewage effluent. Ciprofloxacin and fleroxacin were found in primary and final sewage effluent samples with the contents in the range of 26-87 ng L{sup -1}.

  15. Composite Struts Would Damp Vibrations

    Science.gov (United States)

    Dolgin, Benjamin P.

    1991-01-01

    New design of composite-material (fiber/matrix laminate) struts increases damping of longitudinal vibrations without decreasing longitudinal stiffness or increasing weight significantly. Plies with opposing chevron patterns of fibers convert longitudinal vibrational stresses into shear stresses in intermediate viscoelastic layer, which dissipate vibrational energy. Composite strut stronger than aluminum strut of same weight and stiffness.

  16. Ship Vibration Design Guide

    Science.gov (United States)

    1989-07-01

    Frachtschiffen," Werft Reederie Hafen, 1925. 4-21 Noonan, E. F. "Vibration Considerations for 120,000 CM LNG Ships," NKF: Preliminary Report No. 7107, 25...Ship Response to Ice - A Second Season by C. Daley, J. W. St. John, R. Brown, J. Meyer , and I. Glen 1990 SSC-340 Ice Forces and Ship Response to Ice

  17. Compact Vibration Damper

    Science.gov (United States)

    Ivanco, Thomas G. (Inventor)

    2014-01-01

    A vibration damper includes a rigid base with a mass coupled thereto for linear movement thereon. Springs coupled to the mass compress in response to the linear movement along either of two opposing directions. A converter coupled to the mass converts the linear movement to a corresponding rotational movement. A rotary damper coupled to the converter damps the rotational movement.

  18. Vibrations and Eigenvalues

    Indian Academy of Sciences (India)

    The vibrating string problem is the source of much mathematicsand physics. This article describes Lagrange's formulationof a discretised version of the problem and its solution.This is also the first instance of an eigenvalue problem. Author Affiliations. Rajendra Bhatia1. Ashoka University, Rai, Haryana 131 029, India.

  19. Blade Vibration Measurement System

    Science.gov (United States)

    Platt, Michael J.

    2014-01-01

    The Phase I project successfully demonstrated that an advanced noncontacting stress measurement system (NSMS) could improve classification of blade vibration response in terms of mistuning and closely spaced modes. The Phase II work confirmed the microwave sensor design process, modified the sensor so it is compatible as an upgrade to existing NSMS, and improved and finalized the NSMS software. The result will be stand-alone radar/tip timing radar signal conditioning for current conventional NSMS users (as an upgrade) and new users. The hybrid system will use frequency data and relative mode vibration levels from the radar sensor to provide substantially superior capabilities over current blade-vibration measurement technology. This frequency data, coupled with a reduced number of tip timing probes, will result in a system capable of detecting complex blade vibrations that would confound traditional NSMS systems. The hardware and software package was validated on a compressor rig at Mechanical Solutions, Inc. (MSI). Finally, the hybrid radar/tip timing NSMS software package and associated sensor hardware will be installed for use in the NASA Glenn spin pit test facility.

  20. Vibration Sensitive Keystroke Analysis

    NARCIS (Netherlands)

    Lopatka, M.; Peetz, M.-H.; van Erp, M.; Stehouwer, H.; van Zaanen, M.

    2009-01-01

    We present a novel method for performing non-invasive biometric analysis on habitual keystroke patterns using a vibration-based feature space. With the increasing availability of 3-D accelerometer chips in laptop computers, conventional methods using time vectors may be augmented using a distinct

  1. Nonlinear vibration with control for flexible and adaptive structures

    CERN Document Server

    Wagg, David

    2015-01-01

    This book provides a comprehensive discussion of nonlinear multi-modal structural vibration problems, and shows how vibration suppression can be applied to such systems by considering a sample set of relevant control techniques. It covers the basic principles of nonlinear vibrations that occur in flexible and/or adaptive structures, with an emphasis on engineering analysis and relevant control techniques. Understanding nonlinear vibrations is becoming increasingly important in a range of engineering applications, particularly in the design of flexible structures such as aircraft, satellites, bridges, and sports stadia. There is an increasing trend towards lighter structures, with increased slenderness, often made of new composite materials and requiring some form of deployment and/or active vibration control. There are also applications in the areas of robotics, mechatronics, micro electrical mechanical systems, non-destructive testing and related disciplines such as structural health monitoring. Two broader ...

  2. The diffraction signatures of individual vibrational modes in polyatomic molecules

    Science.gov (United States)

    Ryu, Seol; Weber, Peter M.; Stratt, Richard M.

    2000-01-01

    Though one normally thinks of single-molecule diffraction studies as tools for eliciting molecular geometry, molecular diffraction patterns are really the Fourier transforms of complete molecular wave functions. There is thus at least the possibility of imaging the vibrational wave functions of polyatomic molecules by means of a pump-probe diffraction experiment: the pump laser could prepare a specific vibrational state and an electron or x-ray could then be diffracted off the molecule some short time later. The present paper develops the general theory of diffraction signatures for individual vibrational wave functions in polyatomic molecules and investigates the feasibility of seeing such signatures experimentally using the example of a linear triatomic molecule modeled after CS2. Although aligned molecules in specific vibrational quantum states turn out to exhibit very characteristic diffraction signatures, the signatures of the vibrational wave functions are partially washed out for the complete isotropy expected from gas phase molecules. Nonetheless, it is possible to design a diffraction experiment using a pump-dump sequence with a polarized laser beam which will select a nonisotropic sample of vibrationally excited molecules. We show that the resulting level of anisotropy should enhance the diffraction signature, helping to distinguish different vibrational components. These model calculations therefore suggest the possibility of observing the dynamics of vibrational wave packets using experimentally realizable diffraction techniques.

  3. Animal Communications Through Seismic Vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Peggy (University of Tulsa)

    2001-05-02

    Substrate vibration has been important to animals as a channel of communication for millions of years, but our literature on vibration in this context of biologically relevant information is only decades old. The jaw mechanism of the earliest land vertebrates allowed them to perceive substrate vibrations as their heads lay on the ground long before airborne sounds could be heard. Although the exact mechanism of vibration production and the precise nature of the wave produced are not always understood, recent development of affordable instrumentation to detect and measure vibrations has allowed researchers to answer increasingly sophisticated questions about how animals send and receive vibration signals. We now know that vibration provides information used in predator defense, prey detection, recruitment to food, mate choice, intrasexual competition, and maternal/brood social interactions in a variety of insect orders, spiders, crabs, scorpions, chameleons, frogs, golden moles, mole rats, kangaroos rats, wallabies, elephants and bison.

  4. Vibration Attenuation of Plate Using Multiple Vibration Absorbers

    Directory of Open Access Journals (Sweden)

    Zaman Izzuddin

    2014-07-01

    Full Text Available Vibrations are undesired phenomenon and it can cause harm, distress and unsettling influence to the systems or structures, for example, aircraft, automobile, machinery and building. One of the approach to limit this vibration by introducing passive vibration absorber attached to the structure. In this paper, the adequacy of utilizing passive vibration absorbers are investigated. The vibration absorber system is designed to minimize the vibration of a thin plate fixed along edges. The plate’s vibration characteristics, such as, natural frequency and mode shape are determined using three techniques: theoretical equations, finite element (FE analysis and experiment. The results demonstrate that the first four natural frequencies of fixed-fixed ends plate are 48, 121, 193 and 242 Hz, and these results are corroborated well with theoretical, FE simulation and experiment. The experiment work is further carried out with attached single and multiple vibration absorbers onto plate by tuning the absorber’s frequency to match with the excitation frequency. The outcomes depict that multiple vibration absorbers are more viable in lessening the global structural vibration.

  5. Vibrational Action Spectroscopy of Solids: New Surface-Sensitive Technique

    Science.gov (United States)

    Wu, Zongfang; Płucienik, Agata; Feiten, Felix E.; Naschitzki, Matthias; Wachsmann, Walter; Gewinner, Sandy; Schöllkopf, Wieland; Staemmler, Volker; Kuhlenbeck, Helmut; Freund, Hans-Joachim

    2017-09-01

    Vibrational action spectroscopy employing infrared radiation from a free-electron laser has been successfully used for many years to study the vibrational and structural properties of gas phase aggregates. Despite the high sensitivity of this method no relevant studies have yet been conducted for solid sample surfaces. We have set up an experiment for the application of this method to such targets, using infrared light from the free-electron laser of the Fritz Haber Institute. In this Letter, we present first results of this technique with adsorbed argon and neon atoms as messengers. We were able to detect surface-located vibrations of a thin V2O3(0 0 0 1 ) film on Au(111) as well as adsorbate vibrations, demonstrating that this method is highly surface sensitive. We consider that the dominant channel for desorption of the messenger atoms is direct inharmonic vibrational coupling, which is essentially insensitive to subsurface or bulk vibrations. Another channel is thermal desorption due to sample heating by absorption of infrared light. The high surface sensitivity of the nonthermal channel and its insensitivity to subsurface modes makes this technique an ideal tool for the study of surface-located vibrations.

  6. Good vibrations. [Hydraulic turbines

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, P.

    1994-07-01

    The latest developments in the Voith Turbine Control and Automation System (VTLS), which couples digital control technology to hydropower plant equipment, are described. Prominent among these is the vibration diagnostics module for hydraulic turbines. It provides machine-specific diagnostic logic for a vibration monitoring and analysis system. Of the two other VTLS modules described, the operation module optimizes the control of a power plant with three or more turbines by considering the individual properties of each in turn, recommending which should be run, and how, in order to partition the load for a required power output. The cavitation module is a diagnostic system which enables the limits of operation of the turbines to be extended to bands just outside those determined by cavitation calculations. (3 figures). (UK)

  7. Pickin’ up good vibrations

    CERN Multimedia

    Katarina Anthony

    2015-01-01

    In preparation for the civil engineering work on the HL-LHC, vibration measurements were carried out at the LHC’s Point 1 last month. These measurements will help evaluate how civil engineering work could impact the beam, and will provide crucial details about the site’s geological make-up before construction begins.   A seismic truck at Point 1 generated wave-like vibrations measured by EN/MME. From carrying out R&D to produce state-of-the-art magnets to developing innovative, robust materials capable of withstanding beam impact, the HL-LHC is a multi-faceted project involving many groups and teams across CERN’s departments. It was in this framework that the project management mandated CERN's Mechanical and Materials Engineering (EN/MME) group to measure the propagation of vibrations around Point 1. Their question: can civil engineering work for the HL-LHC – the bulk of which is scheduled for LS2 – begin while the LHC is running? Alth...

  8. Vibrational stability of graphene

    Directory of Open Access Journals (Sweden)

    Yangfan Hu

    2013-05-01

    Full Text Available The mechanical stability of graphene as temperature rises is analyzed based on three different self-consistent phonon (SCP models. Compared with three-dimensional (3-D materials, the critical temperature Ti at which instability occurs for graphene is much closer to its melting temperature Tm obtained from Monte Carlo simulation (Ti ≃ 2Tm, K. V. Zakharchenko, A. Fasolino, J. H. Los, and M. I. Katsnelson, J. Phys. Condens. Matter 23, 202202. This suggests that thermal vibration plays a significant role in melting of graphene while melting for 3-D materials is often dominated by topologic defects. This peculiar property of graphene derives from its high structural anisotropy, which is characterized by the vibrational anisotropic coefficient (VAC, defined upon its Lindermann ratios in different directions. For any carbon based material with a graphene-like structure, the VAC value must be smaller than 5.4 to maintain its stability. It is also found that the high VAC value of graphene is responsible for its negative thermal expansion coefficient at low temperature range. We believe that the VAC can be regarded as a new criterion concerning the vibrational stability of any low-dimensional (low-D materials.

  9. VIBRATION ISOLATION SYSTEM PROBABILITY ANALYSIS

    Directory of Open Access Journals (Sweden)

    Smirnov Vladimir Alexandrovich

    2012-10-01

    Full Text Available The article deals with the probability analysis for a vibration isolation system of high-precision equipment, which is extremely sensitive to low-frequency oscillations even of submicron amplitude. The external sources of low-frequency vibrations may include the natural city background or internal low-frequency sources inside buildings (pedestrian activity, HVAC. Taking Gauss distribution into account, the author estimates the probability of the relative displacement of the isolated mass being still lower than the vibration criteria. This problem is being solved in the three dimensional space, evolved by the system parameters, including damping and natural frequency. According to this probability distribution, the chance of exceeding the vibration criteria for a vibration isolation system is evaluated. Optimal system parameters - damping and natural frequency - are being developed, thus the possibility of exceeding vibration criteria VC-E and VC-D is assumed to be less than 0.04.

  10. Random vibrations theory and practice

    CERN Document Server

    Wirsching, Paul H; Ortiz, Keith

    1995-01-01

    Random Vibrations: Theory and Practice covers the theory and analysis of mechanical and structural systems undergoing random oscillations due to any number of phenomena— from engine noise, turbulent flow, and acoustic noise to wind, ocean waves, earthquakes, and rough pavement. For systems operating in such environments, a random vibration analysis is essential to the safety and reliability of the system. By far the most comprehensive text available on random vibrations, Random Vibrations: Theory and Practice is designed for readers who are new to the subject as well as those who are familiar with the fundamentals and wish to study a particular topic or use the text as an authoritative reference. It is divided into three major sections: fundamental background, random vibration development and applications to design, and random signal analysis. Introductory chapters cover topics in probability, statistics, and random processes that prepare the reader for the development of the theory of random vibrations a...

  11. Chaotic vortex induced vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, J.; Sheridan, J. [Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria 3800 (Australia); Leontini, J. S. [Department of Mechanical and Product Design Engineering, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia); Lo Jacono, D. [Institut de Mécanique des Fluides de Toulouse (IMFT), CNRS, UPS and Université de Toulouse, 31400 Toulouse (France)

    2014-12-15

    This study investigates the nature of the dynamic response of an elastically mounted cylinder immersed in a free stream. A novel method is utilized, where the motion of the body during a free vibration experiment is accurately recorded, and then a second experiment is conducted where the cylinder is externally forced to follow this recorded trajectory. Generally, the flow response during both experiments is identical. However, particular regimes exist where the flow response is significantly different. This is taken as evidence of chaos in these regimes.

  12. Quantum dynamics of vibrational excitations and vibrational charge ...

    Indian Academy of Sciences (India)

    Quantum dynamics of vibrational excitations and vibrational charge transfer processes in H+ + O2 collisions at collision energy 23 eV ... The Fritz Haber Research Centre and The Department of Physical Chemisry, Hebrew University of Jerusalem, Jerusalem, Israel 91904; Department of Chemistry, Indian Institute of ...

  13. An Examination of a Music Appreciation Method Incorporating Tactile Sensations from Artificial Vibrations

    Science.gov (United States)

    Ideguchi, Tsuyoshi; Yoshida, Ryujyu; Ooshima, Keita

    We examined how test subject impressions of music changed when artificial vibrations were incorporated as constituent elements of a musical composition. In this study, test subjects listened to several music samples in which different types of artificial vibration had been incorporated and then subjectively evaluated any resulting changes to their impressions of the music. The following results were obtained: i) Even if rhythm vibration is added to a silent component of a musical composition, it can effectively enhance musical fitness. This could be readily accomplished when actual sounds that had been synchronized with the vibration components were provided beforehand. ii) The music could be listened to more comfortably by adding not only a natural vibration extracted from percussion instruments but also artificial vibration as tactile stimulation according to intentional timing. Furthermore, it was found that the test subjects' impression of the music was affected by a characteristic of the artificial vibration. iii) Adding vibration to high-frequency areas can offer an effective and practical way of enhancing the appeal of a musical composition. iv) The movement sensations of sound and vibration could be experienced when the strength of the sound and vibration are modified in turn. These results suggest that the intentional application of artificial vibration could result in a sensitivity amplification factor on the part of a listener.

  14. Characterization of Train-Induced Vibration and its Effect on Fecal Corticosterone Metabolites in Mice.

    Science.gov (United States)

    Atanasov, Nicholas A; Sargent, Jennifer L; Parmigiani, John P; Palme, Rupert; Diggs, Helen E

    2015-11-01

    Excessive environmental vibrations can have deleterious effects on animal health and experimental results, but they remain poorly understood in the animal laboratory setting. The aims of this study were to characterize train-associated vibration in a rodent vivarium and to assess the effects of this vibration on the reproductive success and fecal corticosterone metabolite levels of mice. An instrumented cage, featuring a high-sensitivity microphone and accelerometer, was used to characterize the vibrations and sound in a vivarium that is near an active railroad. The vibrations caused by the passing trains are 3 times larger in amplitude than are the ambient facility vibrations, whereas most of the associated sound was below the audible range for mice. Mice housed in the room closest to the railroad tracks had pregnancy rates that were 50% to 60% lower than those of mice of the same strains but bred in other parts of the facility. To verify the effect of the train vibrations, we used a custom-built electromagnetic shaker to simulate the train-induced vibrations in a controlled environment. Fecal pellets were collected from male and female mice that were exposed to the simulated vibrations and from unexposed control animals. Analysis of the fecal samples revealed that vibrations similar to those produced by a passing train can increase the levels of fecal corticosterone metabolites in female mice. These increases warrant attention to the effects of vibration on mice and, consequently, on reproduction and experimental outcomes.

  15. Literature survey on anti-vibration gloves

    CSIR Research Space (South Africa)

    Sampson, E

    2003-08-01

    Full Text Available ............................................................................................................... 1 2. HAND ARM VIBRATION SYNDROME (HAVS).......................................................... 2 2.1 Hand-arm vibration................................................. Error! Bookmark not defined. 2.2 Human Response to vibration...

  16. Development of vibrational analysis for detection of antisymmetric shells

    CERN Document Server

    Esmailzadeh-Khadem, S; Rezaee, M

    2002-01-01

    In this paper, vibrational behavior of bodies of revolution with different types of structural faults is studied. Since vibrational characteristics of structures are natural properties of system, the existence of any structural faults causes measurable changes in these properties. Here, this matter is demonstrated. In other words, vibrational behavior of a body of revolution with no structural faults is analyzed by two methods of I) numerical analysis using super sap software, II) Experimental model analysis, and natural frequencies and mode shapes are obtained. Then, different types of cracks are introduced in the structure, and analysis is repeated and the results are compared. Based on this study, one may perform crack detection by measuring the natural frequencies and mode shapes of the samples and comparing with reference information obtained from the vibration analysis of the original structure with no fault.

  17. Vibrational Sensing in Marine Invertebrates

    Science.gov (United States)

    1997-09-30

    VIBRATIONAL SENSING IN MARINE INVERTEBRATES Peter A. Jumars School of Oceanography University of Washington Box 357940 Seattle, WA 98195-7940 (206...DATES COVERED 00-00-1997 to 00-00-1997 4. TITLE AND SUBTITLE Vibrational Sensing in Marine Invertebrates 5a. CONTRACT NUMBER 5b. GRANT NUMBER

  18. Vibrations and Stability: Solved Problems

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003.......Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003....

  19. The origins of vibration theory

    Science.gov (United States)

    Dimarogonas, A. D.

    1990-07-01

    The Ionian School of natural philosophy introduced the scientific method of dealing with natural phenomena and the rigorous proofs for abstract propositions. Vibration theory was initiated by the Pythagoreans in the fifth century BC, in association with the theory of music and the theory of acoustics. They observed the natural frequency of vibrating systems and proved that it is a system property and that it does not depend on the excitation. Pythagoreans determined the fundamental natural frequencies of several simple systems, such as vibrating strings, pipes, vessels and circular plates. Aristoteles and the Peripatetic School founded mechanics and developed a fundamental understanding of statics and dynamics. In Alexandrian times there were substantial engineering developments in the field of vibration. The pendulum as a vibration, and probably time, measuring device was known in antiquity, and was further developed by the end of the first millennium AD.

  20. One-step green synthesis of β-cyclodextrin/iron oxide-reduced graphene oxide nanocomposite with high supramolecular recognition capability: Application for vortex-assisted magnetic solid phase extraction of organochlorine pesticides residue from honey samples.

    Science.gov (United States)

    Mahpishanian, Shokouh; Sereshti, Hassan

    2017-02-17

    In this research, β-cyclodextrin/iron oxide reduced graphene oxide hybrid nanostructure (β-CD/MRGO) with high water dispersability, excellent magnetic responsivity and molecular selectivity was prepared via a facile one step green strategy. The obtained nanomaterial was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and vibrating sample magnetometry (VSM), which confirmed the modification of GO with β-CD and magnetic nanoparticles. The formation mechanism of β-CD/MRGO was also discussed. The prepared magnetic nanocomposite was then applied as adsorbent in the vortex-assisted magnetic solid phase extraction (MSPE) of 16 organochlorine pesticides (OCPs) from honey samples prior to gas chromatography-electron capture detection (GC-ECD) analysis. Optimum extraction conditions have been assessed with respect to vortex time, sample pH, adsorbent amount, and salt concentration as well as desorption conditions (type and volume of desorption solvent and desorption time). A good level of linearity (2-10,000ngkg-1) with satisfactory determination coefficients (R2>0.9966) and suitable precision (%RSDs less than 7.8) was obtained for OCPs under the optimal conditions. The limits of detection and quantification of the method were obtained in the sub-parts per trillion (ppt) to parts per trillion range (LOD: 0.52-3.21ngkg-1; LOQ: 1.73-10.72ngkg-1) based on 3 and 10 signal to noise ratios, respectively. The MSPE method was successfully applied to analysis of OCPs in honey samples with recoveries in the range of 78.8% to 116.2% and RSDs (n=3) below 8.1%. The results demonstrated that β-CD/MRGO could exhibit good supramolecular recognition, enrichment capability and high extraction recoveries toward OCPs. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Experimental Design and Validation of an Accelerated Random Vibration Fatigue Testing Methodology

    OpenAIRE

    Yu Jiang(Center for Statistical and Theoretical Condensed Matter Physics, Zhejiang Normal University, Jinhua City, Zhejiang Province 321004, China); Gun Jin Yun; Li Zhao; Junyong Tao

    2015-01-01

    Novel accelerated random vibration fatigue test methodology and strategy are proposed, which can generate a design of the experimental test plan significantly reducing the test time and the sample size. Based on theoretical analysis and fatigue damage model, several groups of random vibration fatigue tests were designed and conducted with the aim of investigating effects of both Gaussian and non-Gaussian random excitation on the vibration fatigue. First, stress responses at a weak point of a ...

  2. Vibration response of misaligned rotors

    Science.gov (United States)

    Patel, Tejas H.; Darpe, Ashish K.

    2009-08-01

    Misalignment is one of the common faults observed in rotors. Effect of misalignment on vibration response of coupled rotors is investigated in the present study. The coupled rotor system is modelled using Timoshenko beam elements with all six dof. An experimental approach is proposed for the first time for determination of magnitude and harmonic nature of the misalignment excitation. Misalignment effect at coupling location of rotor FE model is simulated using nodal force vector. The force vector is found using misalignment coupling stiffness matrix, derived from experimental data and applied misalignment between the two rotors. Steady-state vibration response is studied for sub-critical speeds. Effect of the types of misalignment (parallel and angular) on the vibration behaviour of the coupled rotor is examined. Along with lateral vibrations, axial and torsional vibrations are also investigated and nature of the vibration response is also examined. It has been found that the misalignment couples vibrations in bending, longitudinal and torsional modes. Some diagnostic features in the fast Fourier transform (FFT) of torsional and longitudinal response related to parallel and angular misalignment have been revealed. Full spectra and orbit plots are effectively used to reveal the unique nature of misalignment fault leading to reliable misalignment diagnostic information, not clearly brought out by earlier studies.

  3. Tissue vibration in prolonged running.

    Science.gov (United States)

    Friesenbichler, Bernd; Stirling, Lisa M; Federolf, Peter; Nigg, Benno M

    2011-01-04

    The impact force in heel-toe running initiates vibrations of soft-tissue compartments of the leg that are heavily dampened by muscle activity. This study investigated if the damping and frequency of these soft-tissue vibrations are affected by fatigue, which was categorized by the time into an exhaustive exercise. The hypotheses were tested that (H1) the vibration intensity of the triceps surae increases with increasing fatigue and (H2) the vibration frequency of the triceps surae decreases with increasing fatigue. Tissue vibrations of the triceps surae were measured with tri-axial accelerometers in 10 subjects during a run towards exhaustion. The frequency content was quantified with power spectra and wavelet analysis. Maxima of local vibration intensities were compared between the non-fatigued and fatigued states of all subjects. In axial (i.e. parallel to the tibia) and medio-lateral direction, most local maxima increased with fatigue (supporting the first hypothesis). In anterior-posterior direction no systematic changes were found. Vibration frequency was minimally affected by fatigue and frequency changes did not occur systematically, which requires the rejection of the second hypothesis. Relative to heel-strike, the maximum vibration intensity occurred significantly later in the fatigued condition in all three directions. With fatigue, the soft tissue of the triceps surae oscillated for an extended duration at increased vibration magnitudes, possibly due to the effects of fatigue on type II muscle fibers. Thus, the protective mechanism of muscle tuning seems to be reduced in a fatigued muscle and the risk of potential harm to the tissue may increase. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Molecular vibrations the theory of infrared and Raman vibrational spectra

    CERN Document Server

    Wilson, E Bright; Cross, Paul C

    1980-01-01

    Pedagogical classic and essential reference focuses on mathematics of detailed vibrational analyses of polyatomic molecules, advancing from application of wave mechanics to potential functions and methods of solving secular determinant.

  5. Avoid heat transfer equipment vibration

    Energy Technology Data Exchange (ETDEWEB)

    Ganapathy, V.

    1987-06-01

    Tube bundles in heat exchangers, boilers, superheaters and heaters are often subject to vibration and noise problems. Vibration can lead to tube thinning and wear, resulting in tube failures. Excessive noise can be a problem to plant operating personnel. Large gas pressure drop across the equipment is also a side effect, which results in large operating costs. With the design checks presented in this paper, one can predict during design if problems associated with noise and vibration are likely to occur in petroleum refineries.

  6. Remote vibration monitoring system using wireless internet data transfer

    Science.gov (United States)

    Lemke, John

    2000-06-01

    Vibrations from construction activities can affect infrastructure projects in several ways. Within the general vicinity of a construction site, vibrations can result in damage to existing structures, disturbance to people, damage to sensitive machinery, and degraded performance of precision instrumentation or motion sensitive equipment. Current practice for monitoring vibrations in the vicinity of construction sites commonly consists of measuring free field or structural motions using velocity transducers connected to a portable data acquisition unit via cables. This paper describes an innovative way to collect, process, transmit, and analyze vibration measurements obtained at construction sites. The system described measures vibration at the sensor location, performs necessary signal conditioning and digitization, and sends data to a Web server using wireless data transmission and Internet protocols. A Servlet program running on the Web server accepts the transmitted data and incorporates it into a project database. Two-way interaction between the Web-client and the Web server is accomplished through the use of a Servlet program and a Java Applet running inside a browser located on the Web client's computer. Advantages of this system over conventional vibration data logging systems include continuous unattended monitoring, reduced costs associated with field data collection, instant access to data files and graphs by project team members, and the ability to remotely modify data sampling schemes.

  7. 14 CFR 33.63 - Vibration.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration. 33.63 Section 33.63 Aeronautics... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.63 Vibration. Each engine... because of vibration and without imparting excessive vibration forces to the aircraft structure. ...

  8. 14 CFR 33.83 - Vibration test.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration test. 33.83 Section 33.83... STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.83 Vibration test. (a) Each engine must undergo vibration surveys to establish that the vibration characteristics of those components that...

  9. 14 CFR 33.33 - Vibration.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration. 33.33 Section 33.33 Aeronautics... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.33 Vibration. The... vibration and without imparting excessive vibration forces to the aircraft structure. ...

  10. 14 CFR 33.43 - Vibration test.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration test. 33.43 Section 33.43... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.43 Vibration test. (a) Each engine must undergo a vibration survey to establish the torsional and bending vibration characteristics...

  11. Rectangular Parallelepiped Vibration in Plane Strain State

    OpenAIRE

    Hanckowiak, Jerzy

    2004-01-01

    In this paper we present a vibration spectrum of a homogenous parallelepiped (HP) under the action of volume and surface forces resulting from the exponent displacements entering the Fourier transforms. Vibration under the action of axial surface tractions and the free vibration are described separately. A relationship between the high frequency vibration and boundary conditions (BC) is also considered.

  12. Deviations of frequency and the mode of vibration of commercially available whole-body vibration training devices.

    Science.gov (United States)

    Kaeding, T S

    2015-06-01

    Research in the field of whole body vibration (WBV) training and the use of it in practice might be hindered by the fact that WBV training devices generate and transmit frequencies and/or modes of vibration which are different to preset adjustments. This research project shall clarify how exact WBV devices apply the by manufacturer information promised preset frequency and mode of vibration. Nine professional devices for WBV training were tested by means of a tri-axial accelerometer. The accelerations of each device were recorded under different settings with a tri-axial accelerometer. Beneath the measurement of different combinations of preset frequency and amplitude the repeatability across 3 successive measurements with the same preset conditions and one measurement under loaded condition were carried out. With 3 exceptions (both Board 3000 & srt medical PRO) we did not find noteworthy divergences between preset and actual applied frequencies. In these 3 devices we found divergences near -25%. Loading the devices did not affect the applied frequency or mode of vibration. There were no important divergences measurable for the applied frequency and mode of vibration regarding repeatability. The results of our measurements cannot be generalized as we only measured one respectively at most two devices of one model in terms of a random sample. Based on these results we strongly recommend that user in practice and research should analyse their WBV training devices regarding applied frequency and mode of vibration.

  13. FT-IR and Raman vibrational microspectroscopies used for spectral biodiagnosis of human tissues

    OpenAIRE

    Lin, Shan-Yang; Li, Mei-Jane; Cheng, Wen-Ting

    2007-01-01

    Fourier transform infrared (FT-IR) and Raman vibrational microspectroscopies used for biomedical diagnosis of human tissues are reviewed from basic principle to biological applications. The advantages and disadvantages of both vibrational microspectroscopies are compared to highlight their efficiency and adaptability for noninvasively investigating the chemical compositions of ultrastructual human tissues at different disease states. Biochemical fingerprints applied to the biological samples ...

  14. Near-field infrared vibrational dynamics and tip-enhanced decoherence.

    Science.gov (United States)

    Xu, Xiaoji G; Raschke, Markus B

    2013-04-10

    Ultrafast infrared spectroscopy can reveal the dynamics of vibrational excitations in matter. In its conventional far-field implementation, however, it provides only limited insight into nanoscale sample volumes due to insufficient spatial resolution and sensitivity. Here, we combine scattering-scanning near-field optical microscopy (s-SNOM) with femtosecond infrared vibrational spectroscopy to characterize the coherent vibrational dynamics of a nanoscopic ensemble of C-F vibrational oscillators of polytetrafluoroethylene (PTFE). The near-field mode transfer between the induced vibrational molecular coherence and the metallic scanning probe tip gives rise to a tip-mediated radiative IR emission of the vibrational free-induction decay (FID). By increasing the tip–sample coupling, we can enhance the vibrational dephasing of the induced coherent vibrational polarization and associated IR emission, with dephasing times up to T2(NF) is approximately equal to 370 fs in competition against the intrinsic far-field lifetime of T2(FF) is approximately equal to 680 fs as dominated by nonradiative damping. Near-field antenna-coupling thus provides for a new way to modify vibrational decoherence. This approach of ultrafast s-SNOM enables the investigation of spatiotemporal dynamics and correlations with nanometer spatial and femtosecond temporal resolution.

  15. Vibrational Damping of Composite Materials

    OpenAIRE

    Biggerstaff, Janet M.

    2006-01-01

    The purpose of this research was to develop new methods of vibrational damping in polymeric composite materials along with expanding the knowledge of currently used vibrational damping methods. A new barrier layer technique that dramatically increased damping in viscoelastic damping materials that interacted with the composite resin was created. A method for testing the shear strength of damping materials cocured in composites was developed. Directional damping materials, where the loss facto...

  16. Vibration Theory, Vol. 1B

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Nielsen, Søren R. K.

    The present collection of MATLAB exercises has been published as a supplement to the textbook, Svingningsteori, Bind 1 and the collection of exercises in Vibration theory, Vol. 1A, Solved Problems. Throughout the exercise references are made to these books. The purpose of the MATLAB exercises...... is to give a better understanding of the physical problems in linear vibration theory and to surpress the mathematical analysis used to solve the problems. For this purpose the MATLAB environment is excellent....

  17. Harmonic vibrations of multispan beams

    DEFF Research Database (Denmark)

    Dyrbye, Claes

    1996-01-01

    Free and forced harmonic vibrations of multispan beams are determined by a method which implies 1 equation regardless of the configuration. The necessary formulas are given in the paper. For beams with simple supports and the same length of all (n) spans, there is a rather big difference between...... the n´th and the (n+1)´th eigenfrequency. The reason for this phenomenon is explained.Keywords: Vibrations, Eigenfrequencies, Beams....

  18. Smart accelerometer. [vibration damage detection

    Science.gov (United States)

    Bozeman, Richard J., Jr. (Inventor)

    1994-01-01

    The invention discloses methods and apparatus for detecting vibrations from machines which indicate an impending malfunction for the purpose of preventing additional damage and allowing for an orderly shutdown or a change in mode of operation. The method and apparatus is especially suited for reliable operation in providing thruster control data concerning unstable vibration in an electrical environment which is typically noisy and in which unrecognized ground loops may exist.

  19. Improved Predictions for Geotechnical Vibrations

    OpenAIRE

    Macijauskas, Darius

    2015-01-01

    In urban areas where the infrastructure is dense and construction of new structures is near existing and sensitive buildings, frequently vibrations, caused by human activities, occur. Generated waves in the soil may adversely affect surrounding buildings. These vibrations have to be predicted a priori by using currently available knowledge of the soil dynamics. Current research, conducted by Deltares research institute, showed that the reliability of methods for prediction of m...

  20. Stress analysis of vibrating pipelines

    Science.gov (United States)

    Zachwieja, Janusz

    2017-03-01

    The pipelines are subject to various constraints variable in time. Those vibrations, if not monitored for amplitude and frequency, may result in both the fatigue damage in the pipeline profile at high stress concentration and the damage to the pipeline supports. If the constraint forces are known, the system response may be determined with high accuracy using analytical or numerical methods. In most cases, it may be difficult to determine the constraint parameters, since the industrial pipeline vibrations occur due to the dynamic effects of the medium in the pipeline. In that case, a vibration analysis is a suitable alternative method to determine the stress strain state in the pipeline profile. Monitoring the pipeline vibration levels involves a comparison between the measured vibration parameters and the permissible values as depicted in the graphs for a specific pipeline type. Unfortunately, in most cases, the studies relate to the petrochemical industry and thus large diameter, long and straight pipelines. For a pipeline section supported on both ends, the response in any profile at the entire section length can be determined by measuring the vibration parameters at two different profiles between the pipeline supports. For a straight pipeline section, the bending moments, variable in time, at the ends of the analysed section are a source of the pipe excitation. If a straight pipe section supported on both ends is excited by the bending moments in the support profile, the starting point for the stress analysis are the strains, determined from the Euler-Bernoulli equation. In practice, it is easier to determine the displacement using the experimental methods, since the factors causing vibrations are unknown. The industrial system pipelines, unlike the transfer pipelines, are straight sections at some points only, which makes it more difficult to formulate the equation of motion. In those cases, numerical methods can be used to determine stresses using the

  1. Specific absorption rate dependence on temperature in magnetic field hyperthermia measured by dynamic hysteresis losses (ac magnetometry).

    Science.gov (United States)

    Garaio, Eneko; Sandre, Olivier; Collantes, Juan-Mari; Garcia, Jose Angel; Mornet, Stéphane; Plazaola, Fernando

    2015-01-09

    Magnetic nanoparticles (NPs) are intensively studied for their potential use for magnetic hyperthermia, a treatment that has passed a phase II clinical trial against severe brain cancer (glioblastoma) at the end of 2011. Their heating power, characterized by the 'specific absorption rate (SAR)', is often considered temperature independent in the literature, mainly because of the difficulties that arise from the measurement methodology. Using a dynamic magnetometer presented in a recent paper, we measure here the thermal dependence of SAR for superparamagnetic iron oxide (maghemite) NPs of four different size-ranges corresponding to mean diameters around 12 nm, 14 nm, 15 nm and 16 nm. The article reports a parametrical study extending from 10 to 60 °C in temperature, from 75 to 1031 kHz in frequency, and from 2 to 24 kA m(-1) in magnetic field strength. It was observed that SAR values of smaller NPs decrease with temperature whereas for the larger sample (16 nm) SAR values increase with temperature. The measured variation of SAR with temperature is frequency dependent. This behaviour is fully explained within the scope of linear response theory based on Néel and Brown relaxation processes, using independent magnetic measurements of the specific magnetization and the magnetic anisotropy constant. A good quantitative agreement between experimental values and theoretical values is confirmed in a tri-dimensional space that uses as coordinates the field strength, the frequency and the temperature.

  2. Vibrational microspectroscopy analysis of human lenses

    Science.gov (United States)

    Paluszkiewicz, C.; Piergies, N.; Sozańska, A.; Chaniecki, P.; Rękas, M.; Miszczyk, J.; Gajda, M.; Kwiatek, W. M.

    2018-01-01

    In this study we present vibrational analysis of healthy (non-affected by cataract) and cataractous human lenses by means of Raman and FTIR spectroscopy methods. The performed analysis provides complex information about the secondary structure of the proteins and conformational changes of the amino acid residues due to the formation of opacification of human lens. Briefly, the changes in the conformation of the Tyr and Trp residues and the protein secondary structure between the healthy and cataractous samples, were recognized. Moreover, the observed spectral pattern suggests that the process of cataract development does not occur uniformly over the entire volume of the lens.

  3. Vibrational modes of nanolines

    Science.gov (United States)

    Heyliger, Paul R.; Flannery, Colm M.; Johnson, Ward L.

    2008-04-01

    Brillouin-light-scattering spectra previously have been shown to provide information on acoustic modes of polymeric lines fabricated by nanoimprint lithography. Finite-element methods for modeling such modes are presented here. These methods provide a theoretical framework for determining elastic constants and dimensions of nanolines from measured spectra in the low gigahertz range. To make the calculations feasible for future incorporation in inversion algorithms, two approximations of the boundary conditions are employed in the calculations: the rigidity of the nanoline/substrate interface and sinusoidal variation of displacements along the nanoline length. The accuracy of these approximations is evaluated as a function of wavenumber and frequency. The great advantage of finite-element methods over other methods previously employed for nanolines is the ability to model any cross-sectional geometry. Dispersion curves and displacement patterns are calculated for modes of polymethyl methacrylate nanolines with cross-sectional dimensions of 65 nm × 140 nm and rectangular or semicircular tops. The vibrational displacements and dispersion curves are qualitatively similar for the two geometries and include a series of flexural, Rayleigh-like, and Sezawa-like modes. This paper is a contribution of the National Institute of Standards and Technology and is not subject to copyright in the United States.

  4. Evaluation of hand-arm vibration reducing effect of anti-vibration glove

    OpenAIRE

    樹野, 淳也; 前田, 節雄; 横田, 和樹; 平, 雄一郎

    2015-01-01

    Many kinds of the anti-vibration glove have been developed for reducing hand-arm vibration during the operation with vibration tools. International standard ISO 10819 evaluates the physical effect of gloves' vibration transmissibility but not evaluates the physiological effect of human hands. Thus, in this paper, we proposed the evaluation using the temporary threshold shift of vibrotactile perception threshold to evaluate the hand-arm vibration reducing effect of anti-vibration glove. We per...

  5. Effect of Moisture Sorption State on Vibrational Properties of Wood

    Science.gov (United States)

    Jianxiong Lu; Jiali Jiang; Yiqiang Wu; Xianjun Li; Zhiyong Cai

    2012-01-01

    The purpose of this study was to investigate the vibrational properties and corresponding anisotropicity in wood during different states of moisture sorption. Samples of maple (Acer spp.) and red oak (Quercus rubra Michx.f.) were moisture conditioned by the adsorption process from an ovendried state and by the desorption process...

  6. Interventions for chronic low back pain: whole body vibration and ...

    African Journals Online (AJOL)

    Objectives. This study explored, described and compared the effects of whole body vibration (WBV) therapy and conventional spinal stabilisation exercises in persons with chronic low back pain (CLBP). Design. A non-randomised sampling technique was used to delineate the base of volunteers gathered by a combination ...

  7. Whole body vibration improves body mass, flexibility and strength in ...

    African Journals Online (AJOL)

    Objectives. This study aimed to determine the effectiveness of whole body vibration (WBV) training for promoting healthrelated physical fitness in sedentary adults. Design. A non-randomised sampling technique was used with an equivalent match-pair comparison group, pre- and posttest design. Volunteers were gathered ...

  8. Random vibration test of Mars Exploration Rover spacecraft

    Science.gov (United States)

    Scharton, T.; Lee, D.

    2003-01-01

    The primary objective of the random vibration test was to identify any hardware problems, which might compromise the mission. The test objectives, configuration, and requirements are briefly described in this presentation, and a representative sample of the measured data is presented.

  9. Characterizing the free and surface-coupled vibrations of heated-tip atomic force microscope cantilevers.

    Science.gov (United States)

    Killgore, Jason P; Tung, Ryan C; Hurley, Donna C

    2014-08-29

    Combining heated-tip atomic force microscopy (HT-AFM) with quantitative methods for determining surface mechanical properties, such as contact resonance force microscopy, creates an avenue for nanoscale thermomechanical property characterization. For nanomechanical methods that employ an atomic force microscope cantilever's vibrational modes, it is essential to understand how the vibrations of the U-shaped HT-AFM cantilever differ from those of a more traditional rectangular lever, for which analytical techniques are better developed. Here we show, with a combination of finite element analysis (FEA) and experiments, that the HT-AFM cantilever exhibits many more readily-excited vibrational modes over typical AFM frequencies compared to a rectangular cantilever. The arms of U-shaped HT-AFM cantilevers exhibit two distinct forms of flexural vibrations that differ depending on whether the two arms are vibrating in-phase or out-of-phase with one another. The in-phase vibrations are qualitatively similar to flexural vibrations in rectangular cantilevers and generally show larger sensitivity to surface stiffness changes than the out-of-phase vibrations. Vibration types can be identified from their frequency and by considering vibration amplitudes in the horizontal and vertical channels of the AFM at different laser spot positions on the cantilever. For identifying contact resonance vibrational modes, we also consider the sensitivity of the resonant frequencies to a change in applied force and hence to tip-sample contact stiffness. Finally, we assess how existing analytical models can be used to accurately predict contact stiffness from contact-resonance HT-AFM results. A simple two-parameter Euler-Bernoulli beam model provided good agreement with FEA for in-phase modes up to a contact stiffness 500 times the cantilever spring constant. By providing insight into cantilever vibrations and exploring the potential of current analysis techniques, our results lay the groundwork

  10. Ultrasonic metal welding with a vibration source using longitudinal and torsional vibration transducers

    Science.gov (United States)

    Asami, Takuya; Tamada, Yosuke; Higuchi, Yusuke; Miura, Hikaru

    2017-07-01

    Conventional ultrasonic metal welding for joining dissimilar metals uses a linear vibration locus, although this method suffers from problems such as low overall weld strength. Our previous studies have shown that ultrasonic welding with a planar vibration locus improves the weld strength. However, the vibration source in our previous studies had problems in longitudinal-torsional vibration controllability and small welding tip. Therefore, the study of the optimal shape of the vibration locus was difficult. Furthermore, improvement of weld strength cannot be expected. We have developed a new ultrasonic vibration source that can control the longitudinal-torsional vibration and can connect to a large welding tip. In this study, we clarified the longitudinal-torsional vibration controllability of the developed ultrasonic vibration source. Moreover, we clarified that using the planar locus of the developed vibration source produced a higher weld strength than our previous studies, and clarified the optimal shape of the vibration locus.

  11. Application of Sub-Micrometer Vibrations to Mitigate Bacterial Adhesion

    Directory of Open Access Journals (Sweden)

    Will R. Paces

    2014-03-01

    Full Text Available As a prominent concern regarding implantable devices, eliminating the threat of opportunistic bacterial infection represents a significant benefit to both patient health and device function. Current treatment options focus on chemical approaches to negate bacterial adhesion, however, these methods are in some ways limited. The scope of this study was to assess the efficacy of a novel means of modulating bacterial adhesion through the application of vibrations using magnetoelastic materials. Magnetoelastic materials possess unique magnetostrictive property that can convert a magnetic field stimulus into a mechanical deformation. In vitro experiments demonstrated that vibrational loads generated by the magnetoelastic materials significantly reduced the number of adherent bacteria on samples exposed to Escherichia coli, Staphylococcus epidermidis and Staphylococcus aureus suspensions. These experiments demonstrate that vibrational loads from magnetoelastic materials can be used as a post-deployment activated means to deter bacterial adhesion and device infection.

  12. Mechanical Vibrations Modeling and Measurement

    CERN Document Server

    Schmitz, Tony L

    2012-01-01

    Mechanical Vibrations:Modeling and Measurement describes essential concepts in vibration analysis of mechanical systems. It incorporates the required mathematics, experimental techniques, fundamentals of modal analysis, and beam theory into a unified framework that is written to be accessible to undergraduate students,researchers, and practicing engineers. To unify the various concepts, a single experimental platform is used throughout the text to provide experimental data and evaluation. Engineering drawings for the platform are included in an appendix. Additionally, MATLAB programming solutions are integrated into the content throughout the text. This book also: Discusses model development using frequency response function measurements Presents a clear connection between continuous beam models and finite degree of freedom models Includes MATLAB code to support numerical examples that are integrated into the text narrative Uses mathematics to support vibrations theory and emphasizes the practical significanc...

  13. DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2004-08-31

    The deep hard rock drilling environment induces severe vibrations into the drillstring, which can cause reduced rates of penetration (ROP) and premature failure of the equipment. The only current means of controlling vibration under varying conditions is to change either the rotary speed or the weight-on-bit (WOB). These changes often reduce drilling efficiency. Conventional shock subs are useful in some situations, but often exacerbate the problems. The objective of this project is development of a unique system to monitor and control drilling vibrations in a ''smart'' drilling system. This system has two primary elements: (1) The first is an active vibration damper (AVD) to minimize harmful axial, lateral and torsional vibrations. The hardness of this damper will be continuously adjusted using a robust, fast-acting and reliable unique technology. (2) The second is a real-time system to monitor drillstring vibration, and related parameters. This monitor adjusts the damper according to local conditions. In some configurations, it may also send diagnostic information to the surface via real-time telemetry. The AVD is implemented in a configuration using magnetorheological (MR) fluid. By applying a current to the magnetic coils in the damper, the viscosity of the fluid can be changed rapidly, thereby altering the damping coefficient in response to the measured motion of the tool. Phase I of this program entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype. Phase I of the project was completed by the revised end date of May 31, 2004. The objectives of this phase were met, and all prerequisites for Phase II have been completed.

  14. DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2004-10-13

    The deep hard rock drilling environment induces severe vibrations into the drillstring, which can cause reduced rates of penetration (ROP) and premature failure of the equipment. The only current means of controlling vibration under varying conditions is to change either the rotary speed or the weight-on-bit (WOB). These changes often reduce drilling efficiency. Conventional shock subs are useful in some situations, but often exacerbate the problems. The objective of this project is development of a unique system to monitor and control drilling vibrations in a ''smart'' drilling system. This system has two primary elements: (1) The first is an active vibration damper (AVD) to minimize harmful axial, lateral and torsional vibrations. The hardness of this damper will be continuously adjusted using a robust, fast-acting and reliable unique technology. (2) The second is a real-time system to monitor drillstring vibration, and related parameters. This monitor adjusts the damper according to local conditions. In some configurations, it may also send diagnostic information to the surface via real-time telemetry. The AVD is implemented in a configuration using magnetorheological (MR) fluid. By applying a current to the magnetic coils in the damper, the viscosity of the fluid can be changed rapidly, thereby altering the damping coefficient in response to the measured motion of the tool. Phase I of this program entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype. Phase I of the project was completed by the revised end date of May 31, 2004. The objectives of this phase were met, and all prerequisites for Phase II have been completed. The month of June, 2004 was primarily occupied with the writing of the Phase I Final Report, the sole deliverable of Phase I, which will be submitted in the next quarter. Redesign of the laboratory prototype and design of the downhole (Phase II) prototype was

  15. Stroboscopic shearography for vibration analysis

    Science.gov (United States)

    Steinchen, Wolfgang; Kupfer, Gerhard; Maeckel, Peter; Voessing, Frank

    1999-09-01

    Digital Shearography, a laser interferometric technique in conjunction with the digital image processing, has the potential for vibration analysis due to its simple optical system and insensitivity against small rigid body motions. This paper will focus on its recent developments for vibration analysis and for nondestructive testing (NDT) by dynamic (harmonical) excitation. With the introduction of real time observation using automatically refreshing reference frame, both small and large rigid body motions are greatly suppressed. The development of a smaller and more mobile measuring device in conjunction with a user guided comfortable program Shearwin enables the digital shearography to be applied easily as an industrial online testing tool.

  16. Vibrational Collapse of Hexapod Packings

    Science.gov (United States)

    Zhao, Yuchen; Ding, Jingqiu; Barés, Jonathan; Zheng, Hu; Dierichs, Karola; Menges, Achim; Behringer, Robert

    2017-06-01

    Columns made of convex noncohesive grains like sand collapse after being released from a confining container. However, structures built from non-convex grains can be stable without external support. In the current experiments, we investigate the effect of vibration on destroying such columns. The change of column height during vertical vibration, can be well characterized by stretched exponential relaxation when the column is short, which is in agreement with previous work, while a faster collapse happens when the column is tall. We investigate the collapse after the fast process including its dependence on column geometry, and on interparticle and basal friction.

  17. Innovative Techniques Simplify Vibration Analysis

    Science.gov (United States)

    2010-01-01

    In the early years of development, Marshall Space Flight Center engineers encountered challenges related to components in the space shuttle main engine. To assess the problems, they evaluated the effects of vibration and oscillation. To enhance the method of vibration signal analysis, Marshall awarded Small Business Innovation Research (SBIR) contracts to AI Signal Research, Inc. (ASRI), in Huntsville, Alabama. ASRI developed a software package called PC-SIGNAL that NASA now employs on a daily basis, and in 2009, the PKP-Module won Marshall s Software of the Year award. The technology is also used in many industries: aircraft and helicopter, rocket engine manufacturing, transportation, and nuclear power."

  18. Energetics, structures, vibrational frequencies, vibrational absorption, vibrational circular dichroism and Raman intensities of Leu-enkephalin

    DEFF Research Database (Denmark)

    Jalkanen, Karl J.

    2003-01-01

    Here we present several low energy conformers of Leu-enkephalin (LeuE) calculated with the density functional theory using the Becke 3LYP hybrid functional and the 6-31G* basis set. The structures, conformational energies, vibrational frequencies, vibrational absorption (VA) intensities......, vibrational circular dichroism (VCD) intensities and Raman scattering intensities are reported for the conformers of LeuE which are expected to be populated at room temperature. The species of LeuE-present in non-polar solvents is the neutral non-ionic species with the NH2 and CO2H groups, in contrast...... to the zwitterionic neutral species with the NH3+ and CO2- groups which predominates in aqueous solution and in the crystal. All of our attempts to find the zwitterionic species in the isolated state failed, with the result that a hydrogen atom from the positively charged N-terminus ammonium group transferred either...

  19. Resonant vibration control of rotating beams

    DEFF Research Database (Denmark)

    Svendsen, Martin Nymann; Krenk, Steen; Høgsberg, Jan Becker

    2011-01-01

    Rotatingstructures,like e.g.wind turbine blades, may be prone to vibrations associated with particular modes of vibration. It is demonstrated, how this type of vibrations can be reduced by using a collocated sensor–actuator system, governed by a resonant controller. The theory is here demonstrated...... modal connectivity, only very limited modal spill-over is generated. The controller acts by resonance and therefore has only a moderate energy consumption, and successfully reduces modal vibrations at the resonance frequency....

  20. A Vibrational Circular Dichroism Microsampling Accessory: Mapping Enhanced Vibrational Circular Dichroism in Amyloid Fibril Films.

    Science.gov (United States)

    Lu, Xuefang; Li, Honggang; Nafie, Jordan W; Pazderka, Tomáš; Pazderková, Markéta; Dukor, Rina K; Nafie, Laurence A

    2017-06-01

    We report the first vibrational circular dichroism (VCD) measurement of spatial heterogeneity in a sample using infrared (IR) microsampling. Vibrational circular dichroism spectra are typically measured using a standard IR cell with an IR beam diameter of 10 mm or greater making it impossible to investigate the spatial heterogeneity of a solid film sample. We have constructed a VCD sampling assembly with either 3 mm or 1 mm spatial resolution. An XY-translation stage was used to measure spectra at different spatial locations producing IR and VCD maps of the sample. In addition, a rotating sample stage was employed using a dual photoelastic modulator (PEM) setup to suppress artifacts due to linear birefringence in solid-phase or film samples. Infrared and VCD mapping of an insulin fibril film has been carried out at both 3 and 1 mm spatial resolution, and lysozyme films were mapped at 1 mm resolution. The IR spectra of different spots vary in intensity due primarily to sample thickness. The changes in the VCD intensity across the map largely correlate to corresponding changes in the IR map. Closer inspection of the insulin map revealed changes in the relative intensities of the VCD spectra not present in the parent IR spectra, which indicated differences in the degree of supramolecular chirality of the fibrils in the various spatial regions. For lysozyme films, in addition to different degrees of supramolecular chirality, reversal of the net fibril chirality was observed. The large signal-to-noise ratio observed at 1 mm resolution implies the feasibility of further increasing the spatial resolution by one or two orders of magnitude for protein fibril film samples.

  1. Low-energy isovector quadrupole vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Faessler, A.; Nojarov, R.

    1986-01-23

    The low-lying isovector quadrupole vibrations are described by an extension of the vibrational model allowing independent proton and neutron vibrations coupled by the symmetry energy. The recently detected low-lying isovector states in nearly spherical nuclei with N=84 are described well concerning their energies and E2/M1 mixing ratios. (orig.).

  2. Ground Vibration Measurements at LHC Point 4

    Energy Technology Data Exchange (ETDEWEB)

    Bertsche, Kirk; /SLAC; Gaddi, Andrea; /CERN

    2012-09-17

    Ground vibration was measured at Large Hadron Collider (LHC) Point 4 during the winter shutdown in February 2012. This report contains the results, including power and coherence spectra. We plan to collect and analyze vibration data from representative collider halls to inform specifications for future linear colliders, such as ILC and CLIC. We are especially interested in vibration correlations between final focus lens locations.

  3. Rotor Vibration Reduction via Active Hybrid Bearings

    DEFF Research Database (Denmark)

    Nicoletti, Rodrigo; Santos, Ilmar

    2002-01-01

    The use of fluid power to reduce and control rotor vibration in rotating machines is investigated. An active hybrid bearing is studied, whose main objective is to reduce wear and vibration between rotating and stationary machinery parts. By injecting pressurised oil into the oil film, through...... with experiment, and simulations show the feasibility of controlling shaft vibration through this active device....

  4. 33 CFR 159.103 - Vibration test.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vibration test. 159.103 Section...) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.103 Vibration test. The device... subjected to a sinusoidal vibration for a period of 12 hours, 4 hours in each of the x, y, and z planes, at...

  5. 14 CFR 27.907 - Engine vibration.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine vibration. 27.907 Section 27.907... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant General § 27.907 Engine vibration. (a) Each engine must be installed to prevent the harmful vibration of any part of the engine or rotorcraft. (b) The addition of the...

  6. 14 CFR 29.251 - Vibration.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration. 29.251 Section 29.251... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Miscellaneous Flight Requirements § 29.251 Vibration. Each part of the rotorcraft must be free from excessive vibration under each appropriate speed and power...

  7. 14 CFR 29.907 - Engine vibration.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine vibration. 29.907 Section 29.907... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant General § 29.907 Engine vibration. (a) Each engine must be installed to prevent the harmful vibration of any part of the engine or rotorcraft. (b) The...

  8. 14 CFR 27.251 - Vibration.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration. 27.251 Section 27.251... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Miscellaneous Flight Requirements § 27.251 Vibration. Each part of the rotorcraft must be free from excessive vibration under each appropriate speed and power...

  9. 49 CFR 178.608 - Vibration standard.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Vibration standard. 178.608 Section 178.608... Testing of Non-bulk Packagings and Packages § 178.608 Vibration standard. (a) Each packaging must be capable of withstanding, without rupture or leakage, the vibration test procedure outlined in this section...

  10. 49 CFR 178.985 - Vibration test.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Vibration test. 178.985 Section 178.985... Testing of Large Packagings § 178.985 Vibration test. (a) General. All rigid Large Packaging and flexible Large Packaging design types must be capable of withstanding the vibration test. (b) Test method. (1) A...

  11. Vibration measurements on timber frame floors

    NARCIS (Netherlands)

    Kuilen, J.W.G. van de; Oosterhout, G.P.C. van; Donkervoort, R.

    1998-01-01

    In the design of lightweight floors vibrational aspects become more and more important. With the foreseen introduction of Eurocode 5 the vibration of timber floors becomes a part of the design for serviceability. Design rules for the vibrational behaviour are given in Eurocode 5. The first rule is

  12. Vibrations in a moving flexible robot arm

    Science.gov (United States)

    Wang, P. K. C.; Wei, Jin-Duo

    1987-01-01

    The vibration in a flexible robot arm modeled by a moving slender prismatic beam is considered. It is found that the extending and contracting motions have destabilizing and stabilizing effects on the vibratory motions, respectively. The vibration analysis is based on a Galerkin approximation with time-dependent basis functions. Typical numerical results are presented to illustrate the qualitative features of vibrations.

  13. Vibration Theory, Vol. 1A

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.

    The present collection of solved problems has been published as a supplement to the textbook Svingningsteori. Bind 1. Lineær svingningsteori,Aalborg tekniske Universitetsforlag, 1991, whicj is used in the introductory course on linear vibration theory that is being given on th e8th semester...

  14. Vibration Damping Circuit Card Assembly

    Science.gov (United States)

    Hunt, Ronald Allen (Inventor)

    2016-01-01

    A vibration damping circuit card assembly includes a populated circuit card having a mass M. A closed metal container is coupled to a surface of the populated circuit card at approximately a geometric center of the populated circuit card. Tungsten balls fill approximately 90% of the metal container with a collective mass of the tungsten balls being approximately (0.07) M.

  15. Wideband Piezomagnetoelastic Vibration Energy Harvesting

    DEFF Research Database (Denmark)

    Lei, Anders; Thomsen, Erik Vilain

    2014-01-01

    This work presents a small-scale wideband piezomagnetoelastic vibration energy harvester (VEH) aimed for operation at frequencies of a few hundred Hz. The VEH consists of a tape-casted PZT cantilever with thin sheets of iron foil attached on each side of the free tip. The wideband operation...

  16. Ultrafast vibrations of gold nanorings

    DEFF Research Database (Denmark)

    Kelf, T; Tanaka, Y; Matsuda, O

    2011-01-01

    We investigate the vibrational modes of gold nanorings on a silica substrate with an ultrafast optical technique. By comparison with numerical simulations, we identify several resonances in the gigahertz range associated with axially symmetric deformations of the nanoring and substrate. We...

  17. Effect of shelf aging on vibration transmissibility of anti-vibration gloves.

    Science.gov (United States)

    Shibata, Nobuyuki

    2017-10-05

    Anti-vibration gloves have been used in real workplaces to reduce vibration transmitted through hand-held power tools to the hand. Generally materials used for vibration attenuation in gloves are resilient materials composed of certain synthetic and/or composite polymers. The mechanical characteristics of the resilient materials used in anti-vibration gloves are prone to be influenced by environmental conditions such as temperature, humidity, and photo-irradiation, which cause material degradation and aging. This study focused on the influence of shelf aging on the vibration attenuation performance of air-packaged anti-vibration gloves following 2 years of shelf aging. Effects of shelf aging on the vibration attenuation performance of anti-vibration gloves were examined according to the Japan industrial standard JIS T8114 test protocol. The findings indicate that shelf aging induces the reduction of vibration attenuation performance in air-packaged anti-vibration gloves.

  18. Dynamic Assessment of Vibration of Tooth Modification Gearbox Using Grey Bootstrap Method

    Directory of Open Access Journals (Sweden)

    Hui-liang Wang

    2015-01-01

    Full Text Available The correlation analysis between gear modification and vibration characteristics of transmission system was difficult to quantify; a novel small sample vibration of gearbox prediction method based on grey system theory and bootstrap theory was presented. The method characterized vibration base feature of tooth modification gearbox by developing dynamic uncertainty, estimated true value, and systematic error measure, and these parameters could indirectly dynamically evaluate the effect of tooth modification. The method can evaluate the vibration signal of gearbox with installation of no tooth modification gear and topological modification gear, respectively, considering that 100% reliability is the constraints condition and minimum average uncertainty is the target value. Computer simulation and experiment results showed that vibration amplitude of gearbox was decreased partly due to topological tooth modification, and each value of average dynamic uncertainty, mean true value, and systematic error measure was smaller than the no tooth modification value. The study provided an important guide for tooth modification, dynamic performance optimization.

  19. Effect of Vibration on Pain Response to Heel Lance: A Pilot Randomized Control Trial.

    Science.gov (United States)

    McGinnis, Kate; Murray, Eileen; Cherven, Brooke; McCracken, Courtney; Travers, Curtis

    2016-12-01

    Applied mechanical vibration in pediatric and adult populations has been shown to be an effective analgesic for acute and chronic pain, including needle pain. Studies among the neonatal population are lacking. According to the Gate Control Theory, it is expected that applied mechanical vibration will have a summative effect with standard nonpharmacologic pain control strategies, reducing behavioral and physiologic pain responses to heel lancing. To determine the safety and efficacy of mechanical vibration for relief of heel lance pain among neonates. In this parallel design randomized controlled trial, eligible enrolled term or term-corrected neonates (n = 56) in a level IV neonatal intensive care unit were randomized to receive either sucrose and swaddling or sucrose, swaddling, and vibration for heel lance analgesia. Vibration was applied using a handheld battery-powered vibrator (Norco MiniVibrator, Hz = 92) to the lateral aspect of the lower leg along the sural dermatome throughout the heel lance procedure. Neonatal Pain, Agitation, and Sedation Scale (N-PASS) scores, heart rate, and oxygen saturations were collected at defined intervals surrounding heel lancing. Infants in the vibration group (n = 30) had significantly lower N-PASS scores and more stable heart rates during heel stick (P = .006, P = .037) and 2 minutes after heel lance (P = .002, P = .016) than those in the nonvibration group. There were no adverse behavioral or physiologic responses to applied vibration in the sample. Applied mechanical vibration is a safe and effective method for managing heel lance pain. This pilot study suggests that mechanical vibration warrants further exploration as a nonpharmacologic pain management tool among the neonatal population.

  20. The effect of whole-body resonance vibration in a porcine model of spinal cord injury.

    Science.gov (United States)

    Streijger, Femke; Lee, Jae H T; Chak, Jason; Dressler, Dan; Manouchehri, Neda; Okon, Elena B; Anderson, Lisa M; Melnyk, Angela D; Cripton, Peter A; Kwon, Brian K

    2015-06-15

    Whole-body vibration has been identified as a potential stressor to spinal cord injury (SCI) patients during pre-hospital transportation. However, the effect that such vibration has on the acutely injured spinal cord is largely unknown, particularly in the frequency domain of 5 Hz in which resonance of the spine occurs. The objective of the study was to investigate the consequences of resonance vibration on the injured spinal cord. Using our previously characterized porcine model of SCI, we subjected animals to resonance vibration (5.7±0.46 Hz) or no vibration for a period of 1.5 or 3.0 h. Locomotor function was assessed weekly and cerebrospinal fluid (CSF) samples were collected to assess different inflammatory and injury severity markers. Spinal cords were evaluated histologically to quantify preserved white and gray matter. No significant differences were found between groups for CSF levels of monocyte chemotactic protein-1, interleukin 6 (IL-6) and lL-8. Glial fibrillary acidic protein levels were lower in the resonance vibration group, compared with the non-vibrated control group. Spared white matter tissue was increased within the vibrated group at 7 d post-injury but this difference was not apparent at the 12-week time-point. No significant difference was observed in locomotor recovery following resonance vibration of the spine. Here, we demonstrate that exposure to resonance vibration for 1.5 or 3 h following SCI in our porcine model is not detrimental to the functional or histological outcomes. Our observation that a 3.0-h period of vibration at resonance frequency induces modest histological improvement at one week post-injury warrants further study.

  1. The effects of sound level and vibration magnitude on the relative discomfort of noise and vibration.

    Science.gov (United States)

    Huang, Yu; Griffin, Michael J

    2012-06-01

    The relative discomfort caused by noise and vibration, how this depends on the level of noise and the magnitude of vibration, and whether the noise and vibration are presented simultaneously or sequentially has been investigated in a laboratory study with 20 subjects. Noise and vertical vibration were reproduced with all 49 combinations of 7 levels of noise and 7 magnitudes of vibration to allow the discomfort caused by one of the stimuli to be judged relative to the other stimulus using magnitude estimation. In four sessions, subjects judged noise relative to vibration and vibration relative to noise, with both simultaneous and sequential presentations of the stimuli. The equivalence of noise and vibration was not greatly dependent on whether the stimuli were simultaneous or sequential, but highly dependent on whether noise was judged relative to vibration or vibration was judged relative to noise. When judging noise, higher magnitude vibrations appeared to mask the discomfort caused by low levels of noise. When judging vibration, higher level noises appeared to mask the discomfort caused by low magnitudes of vibration. The judgment of vibration discomfort was more influenced by noise than the judgment of noise discomfort was influenced by vibration.

  2. Microgravity Active Vibration Isolation System on Parabolic Flights

    Science.gov (United States)

    Dong, Wenbo; Pletser, Vladimir; Yang, Yang

    2016-07-01

    The Microgravity Active Vibration Isolation System (MAIS) aims at reducing on-orbit vibrations, providing a better controlled lower gravity environment for microgravity physical science experiments. The MAIS will be launched on Tianzhou-1, the first cargo ship of the China Manned Space Program. The principle of the MAIS is to suspend with electro-magnetic actuators a scientific payload, isolating it from the vibrating stator. The MAIS's vibration isolation capability is frequency-dependent and a decrease of vibration of about 40dB can be attained. The MAIS can accommodate 20kg of scientific payload or sample unit, and provide 30W of power and 1Mbps of data transmission. The MAIS is developed to support microgravity scientific experiments on manned platforms in low earth orbit, in order to meet the scientific requirements for fluid physics, materials science, and fundamental physics investigations, which usually need a very quiet environment, increasing their chances of success and their scientific outcomes. The results of scientific experiments and technology tests obtained with the MAIS will be used to improve future space based research. As the suspension force acting on the payload is very small, the MAIS can only be operative and tested in a weightless environment. The 'Deutsches Zentrum für Luft- und Raumfahrt e.V.' (DLR, German Aerospace Centre) granted a flight opportunity to the MAIS experiment to be tested during its 27th parabolic flight campaign of September 2015 performed on the A310 ZERO-G aircraft managed by the French company Novespace, a subsidiary of the 'Centre National d'Etudes Spatiales' (CNES, French Space Agency). The experiment results confirmed that the 6 degrees of freedom motion control technique was effective, and that the vibration isolation performance fulfilled perfectly the expectations based on theoretical analyses and simulations. This paper will present the design of the MAIS and the experiment results obtained during the

  3. Transient vibration of wind turbine blades

    Science.gov (United States)

    Li, Yuanzhe; Li, Minghai; Jiang, Feng

    2017-09-01

    This article aims to the transient vibration of wind turbine blades. We firstly introduce transient vibration and previous studies in this area. The report then shows the fundamental equations and derivation of Euler Equation. A 3-D beam are created to compare the analytical and numerical result. In addition we operate the existing result and Patran result of a truncation wedge beam, especially the frequencies of free vibration and transient vibration. Transient vibration cannot be vanished but in some case it can be reduced.

  4. Multiple Rabi Splittings under Ultrastrong Vibrational Coupling.

    Science.gov (United States)

    George, Jino; Chervy, Thibault; Shalabney, Atef; Devaux, Eloïse; Hiura, Hidefumi; Genet, Cyriaque; Ebbesen, Thomas W

    2016-10-07

    From the high vibrational dipolar strength offered by molecular liquids, we demonstrate that a molecular vibration can be ultrastrongly coupled to multiple IR cavity modes, with Rabi splittings reaching 24% of the vibration frequencies. As a proof of the ultrastrong coupling regime, our experimental data unambiguously reveal the contributions to the polaritonic dynamics coming from the antiresonant terms in the interaction energy and from the dipolar self-energy of the molecular vibrations themselves. In particular, we measure the opening of a genuine vibrational polaritonic band gap of ca. 60 meV. We also demonstrate that the multimode splitting effect defines a whole vibrational ladder of heavy polaritonic states perfectly resolved. These findings reveal the broad possibilities in the vibrational ultrastrong coupling regime which impact both the optical and the molecular properties of such coupled systems, in particular, in the context of mode-selective chemistry.

  5. Vibrations on board and health effects

    DEFF Research Database (Denmark)

    Jensen, Anker; Jepsen, Jørgen Riis

    2014-01-01

    for such relation among seafarers except for fishermen, who, however, are also exposed to additional recognised physical risk factors at work. The assessment and reduction of vibrations by naval architects relates to technical implications of this impact for the ships’ construction, but has limited value......There is only limited knowledge of the exposure to vibrations of ships’ crews and their risk of vibration-induced health effects. Exposure to hand-arm vibrations from the use of vibrating tools at sea does not differ from that in the land-based trades. However, in contrast to most other work places...... of the health consequences of whole body vibrations in land-transportation, such exposure at sea may affect ships’ passengers and crews. While the relation of back disorders to high levels of whole body vibration has been demonstrated among e.g. tractor drivers, there are no reported epidemiological evidence...

  6. Vibrational assignments for 7-methyl-4-bromomethylcoumarin, as aided by RHF and B3LYP/6-31G* calculations.

    Science.gov (United States)

    Sortur, Veenasangeeta; Yenagi, Jayashree; Tonannavar, J; Jadhav, V B; Kulkarni, M V

    2008-11-15

    Infrared (4000-400 cm(-1)) and Raman (3500-50 cm(-1)) spectral measurements have been made for the solid sample of 7-methyl-4-bromomethylcoumarin. Electronic structure calculations at RHF/6-31G* and B3LYP/6-31G* levels of theory have been performed, giving equilibrium geometries, harmonic vibrational spectra and normal modes. Different orientations of bromomethyl group have yielded only two conformers, of which the most stable one lying lower from the other conformer by approximately 7.99 kJ/mol, is non-planar with no symmetry. A complete assignment of the vibrational modes, aided by the calculations, has been proposed. Coupled vibrations are manifest in many modes. Some spectral features, compared to 6-methyl-4-bromomethylcoumarin, show changes across both IR and Raman spectra, involving mainly skeletal vibrations, and to a lesser degree, methyl and bromomethyl vibrations. Low-frequency vibrations below 150 cm(-1) are assigned to lattice modes.

  7. Vibration characteristics of casing string under the exciting force of an electric vibrator

    Directory of Open Access Journals (Sweden)

    Yiyong Yin

    2017-11-01

    Full Text Available Vibration cementing is a new technique that can significantly improve the bond strength of cementing interface. To popularize this technique, it is necessary to solve the key problem of how to make cementing string generate downhole radial vibration in the WOC stage. For this purpose, an electric vibrator was developed. With this vibrator, electric energy is converted into mechanical energy by means of a high-temperature motor vibration unit. The motor vibration unit rotates the eccentric block through an output shaft to generate an exciting source, which produces an axial-rotating exciting force at the bottom of the casing string. Then, the vibration characteristics of vertical well casing string under the exciting force were analyzed by using the principal coordinate analysis method, and the response model of casing string to an electric vibrator was developed. Finally, the effects of casing string length, exciting force and vibration frequency on the vibration amplitude at the lowermost of the casing string were analyzed based on a certain casing program. It is indicated that the casing string length and the square of vibration frequency are inversely proportional to the vibration amplitude at the lowermost of the casing string, and the exciting force is proportional to the vibration amplitude at the lowermost of the casing string. These research results provide a theoretical support for the application of vibration cementing technology to the cementing sites with different requirements on well depth and amplitude.

  8. Facile synthesis of multifunctional attapulgite/Fe{sub 3}O{sub 4}/polyaniline nanocomposites for magnetic dispersive solid phase extraction of benzoylurea insecticides in environmental water samples

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaoling; Qiao, Kexin; Ye, Yiren; Yang, Miyi; Li, Jing; Gao, Haixiang; Zhang, Sanbing; Zhou, Wenfeng; Lu, Runhua, E-mail: rhlu@cau.edu.cn

    2016-08-31

    In this study, the superparamagnetic attapulgite/Fe{sub 3}O{sub 4}/polyaniline (ATP/Fe{sub 3}O{sub 4}/PANI) nanocomposites were successfully synthesized by a one-pot method. Fe (III) was applied as both the oxidant for the oxidative polymerization of aniline and the single iron source of Fe{sub 3}O{sub 4} formed by the redox reaction between aniline and Fe (III). The ATP/Fe{sub 3}O{sub 4}/PANI was used as sorbent for magnetic dispersive solid phase extraction (MDSPE) of benzoylurea insecticides (BUs) in environmental water samples. The as-prepared nanocomposite sorbents were characterized by Fourier transform infrared spectra (FT-IR), X Ray diffraction (XRD), scanning electron microscopy(SEM), transmission electron microscopy (TEM), and vibrating sample magnetometry. Various experimental parameters affecting the ATP/Fe{sub 3}O{sub 4}/PANI-based MDSPE procedure, including the composition of the nanocomposite sorbents, amount of ATP/Fe{sub 3}O{sub 4}/PANI nanocomposites, vortex time, pH, and desorption conditions were investigated. Under the optimal conditions, a good linearity was observed for all target analytes, with correlation coefficients (r{sup 2}) ranging from 0.9985 to 0.9997; the limits of detection (LOD) were in the range of 0.02–0.43 μg L{sup −1}, and the recoveries of analytes using the proposed method ranged between 77.37% and 103.69%. The sorbents exhibited an excellent reproducibility in the range of 1.52–5.27% in extracting the five target analytes. In addition, the intra-day and inter-day precision values were found to be in the range of 0.78–6.86% and 1.66–8.41%, respectively. Finally, the proposed ATP/Fe{sub 3}O{sub 4}/PANI-based MDSPE method was successfully applied to analyze river water samples by rapid preconcentration of BUs. - Highlights: • A novel superparamagnetic ATP/Fe{sub 3}O{sub 4}/PANI nanocomposite was first introduced in MDSPE. • ATP/Fe{sub 3}O{sub 4}/PANI nanocomposites exhibited fast adsorption and desorption

  9. Vibrational damping of composite materials

    Science.gov (United States)

    Biggerstaff, Janet M.

    The purpose of this research was to develop new methods of vibrational damping in polymeric composite materials along with expanding the knowledge of currently used vibrational damping methods. A new barrier layer technique that dramatically increased damping in viscoelastic damping materials that interacted with the composite resin was created. A method for testing the shear strength of damping materials cocured in composites was developed. Directional damping materials, where the loss factor and modulus could be tailored by changing the angle, were produced and investigated. The addition of particles between composite prepreg layers to increase damping was studied. Electroviscoelastic materials that drastically changed properties such as loss factor and modulus with an applied voltage were manufactured and tested.

  10. Vibration of imperfect rotating disk

    Directory of Open Access Journals (Sweden)

    Půst L.

    2011-12-01

    Full Text Available This study is concerned with the theoretical and numerical calculations of the flexural vibrations of a bladed disk. The main focus of this study is to elaborate the basic background for diagnostic and identification methods for ascertaining the main properties of the real structure or an experimental model of turbine disks. The reduction of undesirable vibrations of blades is proposed by using damping heads, which on the experimental model of turbine disk are applied only on a limited number of blades. This partial setting of damping heads introduces imperfection in mass, stiffness and damping distribution on the periphery and leads to more complicated dynamic properties than those of a perfect disk. Calculation of FEM model and analytic—numerical solution of disk behaviour in the limited (two modes frequency range shows the splitting of resonance with an increasing speed of disk rotation. The spectrum of resonance is twice denser than that of a perfect disk.

  11. Vibrational coupling in plasmonic molecules.

    Science.gov (United States)

    Yi, Chongyue; Dongare, Pratiksha D; Su, Man-Nung; Wang, Wenxiao; Chakraborty, Debadi; Wen, Fangfang; Chang, Wei-Shun; Sader, John E; Nordlander, Peter; Halas, Naomi J; Link, Stephan

    2017-10-31

    Plasmon hybridization theory, inspired by molecular orbital theory, has been extremely successful in describing the near-field coupling in clusters of plasmonic nanoparticles, also known as plasmonic molecules. However, the vibrational modes of plasmonic molecules have been virtually unexplored. By designing precisely configured plasmonic molecules of varying complexity and probing them at the individual plasmonic molecule level, intramolecular coupling of acoustic modes, mediated by the underlying substrate, is observed. The strength of this coupling can be manipulated through the configuration of the plasmonic molecules. Surprisingly, classical continuum elastic theory fails to account for the experimental trends, which are well described by a simple coupled oscillator picture that assumes the vibrational coupling is mediated by coherent phonons with low energies. These findings provide a route to the systematic optical control of the gigahertz response of metallic nanostructures, opening the door to new optomechanical device strategies. Published under the PNAS license.

  12. A night with good vibrations

    CERN Multimedia

    2002-01-01

    Next week-end, the Geneva Science History Museum invites you to a Science Night under the banner of waves and vibrations. Scientists, artists and storytellers from more than forty institutes and local or regional associations will show that waves and vibrations form an integral part of our environment. You will be able to get in contact with the nature of waves through interactive exhibitions on sound and light and through hands-on demonstrations arranged in the Park of the Perle du Lac. On the CERN stand, you will be able to measure the speed of light with a bar of chocolate, and understand the scattering of waves with plastic ducks. Amazing, no? In addition to the stands, the Night will offer many other activities: reconstructions of experiments, a play, a concert of crystal glasses, an illuminated fountain, a house of spirits. More information Science Night, 6 and 7 July, Park of the Perle du Lac, Geneva

  13. Vibration Control in Periodic Structures

    DEFF Research Database (Denmark)

    Høgsberg, Jan Becker

    2017-01-01

    Within the framework of periodic structures, the calibration of RL shunted piezoelectric inclusions is investigated with respect to maximum damping of a particular wave form. A finite element setting is assumed, with local shunted inclusions inside the unit cell. The effect of the shunts is repre....... The presentation contains dispersion diagrams and vibration amplitude curves for the optimally calibrated RL shunt system in a 1-D periodic structure with local piezoelectric inclusions....

  14. Laser-Doppler vibrating tube densimeter for measurements at high temperatures and pressures.

    Science.gov (United States)

    Aida, Tsutomu; Yamazaki, Ai; Akutsu, Makoto; Ono, Takumi; Kanno, Akihiro; Hoshina, Taka-aki; Ota, Masaki; Watanabe, Masaru; Sato, Yoshiyuki; Smith, Richard L; Inomata, Hiroshi

    2007-11-01

    A laser-Doppler vibrometer was used to measure the vibration of a vibrating tube densimeter for measuring P-V-T data at high temperatures and pressures. The apparatus developed allowed the control of the residence time of the sample so that decomposition at high temperatures could be minimized. A function generator and piezoelectric crystal was used to excite the U-shaped tube in one of its normal modes of vibration. Densities of methanol-water mixtures are reported for at 673 K and 40 MPa with an uncertainty of 0.009 g/cm3.

  15. Package security recorder of vibration

    Science.gov (United States)

    Wang, Xiao-na; Hu, Jin-liang; Song, Shi-de

    2013-08-01

    This paper introduces a new kind of electronic product — Package Security Recorder of Vibration. It utilizes STC89C54RD+ LQFP-44 MCU as its main controller. At the same time, it also utilizes Freescale MMA845A 3-Axis 8-bit/12-bit Digital Accelerometer and Maxim DS1302 Trickle Charge Timekeeping Chip. It utilizes the MCU to read the value of the accelerometer and the value of the timekeeping chip, and records the data into the inner E2PROM of MCU. The whole device achieves measuring, reading and recording the time of the vibration and the intensity of the vibration. When we need the data, we can read them out. The data can be used in analyzing the condition of the cargo when it transported. The device can be applied to monitor the security of package. It solves the problem of responsibility affirming, when the valuable cargo are damaged while it transported. It offers powerful safeguard for the package. It's very value for application.

  16. Material removal mechanisms in abrasive vibration polishing of complex molds

    Science.gov (United States)

    Brinksmeier, E.; Riemer, O.; Schulte, H.

    2010-10-01

    Optical and medical industries are demanding a large variety of optical elements exhibiting complex geometries and multitude opto-functional areas in the range of a few millimeters [1]. Therefore, mold inserts made of steel or carbides must be finished by polishing for the replication of glass and plastic lenses [2]. For polishing theses complex components in the shape of localized cavities or grooves the application of rotating polishing pads is very limited. Established polishing processes are not applicable, so state of the art is a time consuming and therefore expensive polishing procedures by hand. An automated process with conventional polishing machines is impossible because of the complex mold insert geometry. The authors will present the development of a new abrasive polishing process for finishing these complex mold geometries to optical quality. The necessary relative velocity in the contact area between polishing pad and workpiece surface is exclusively realized by vibration motions which is an advantage over vibration assisted rotating polishing processes. The absence of rotation of the pad opens up the possibility to machine new types of surface geometries. The specific influence factors of vibration polishing were analyzed and will be presented. The determination of material removal behavior and polishing effect on planar steel samples has shown that the conventional abrasive polishing hypothesis of Preston is applicable to the novel vibration polishing process. No overlaid chemical material removal appears.

  17. Sparse Representation Based Frequency Detection and Uncertainty Reduction in Blade Tip Timing Measurement for Multi-Mode Blade Vibration Monitoring

    Science.gov (United States)

    Pan, Minghao; Yang, Yongmin; Guan, Fengjiao; Hu, Haifeng; Xu, Hailong

    2017-01-01

    The accurate monitoring of blade vibration under operating conditions is essential in turbo-machinery testing. Blade tip timing (BTT) is a promising non-contact technique for the measurement of blade vibrations. However, the BTT sampling data are inherently under-sampled and contaminated with several measurement uncertainties. How to recover frequency spectra of blade vibrations though processing these under-sampled biased signals is a bottleneck problem. A novel method of BTT signal processing for alleviating measurement uncertainties in recovery of multi-mode blade vibration frequency spectrum is proposed in this paper. The method can be divided into four phases. First, a single measurement vector model is built by exploiting that the blade vibration signals are sparse in frequency spectra. Secondly, the uniqueness of the nonnegative sparse solution is studied to achieve the vibration frequency spectrum. Thirdly, typical sources of BTT measurement uncertainties are quantitatively analyzed. Finally, an improved vibration frequency spectra recovery method is proposed to get a guaranteed level of sparse solution when measurement results are biased. Simulations and experiments are performed to prove the feasibility of the proposed method. The most outstanding advantage is that this method can prevent the recovered multi-mode vibration spectra from being affected by BTT measurement uncertainties without increasing the probe number. PMID:28758952

  18. Actively controlled vibration welding system and method

    Science.gov (United States)

    Cai, Wayne W.; Kang, Bongsu; Tan, Chin-An

    2013-04-02

    A vibration welding system includes a controller, welding horn, an active material element, and anvil assembly. The assembly may include an anvil body connected to a back plate and support member. The element, e.g., a piezoelectric stack or shape memory alloy, is positioned with respect to the assembly. The horn vibrates in a desirable first direction to form a weld on a work piece. The element controls any vibrations in a second direction by applying calibrated response to the anvil body in the second direction. A method for controlling undesirable vibrations in the system includes positioning the element with respect to the anvil assembly, connecting the anvil body to the support member through the back plate, vibrating the horn in a desirable first direction, and transmitting an input signal to the element to control vibration in an undesirable second direction.

  19. Coupled rotor/airframe vibration analysis

    Science.gov (United States)

    Sopher, R.; Studwell, R. E.; Cassarino, S.; Kottapalli, S. B. R.

    1982-01-01

    A coupled rotor/airframe vibration analysis developed as a design tool for predicting helicopter vibrations and a research tool to quantify the effects of structural properties, aerodynamic interactions, and vibration reduction devices on vehicle vibration levels is described. The analysis consists of a base program utilizing an impedance matching technique to represent the coupled rotor/airframe dynamics of the system supported by inputs from several external programs supplying sophisticated rotor and airframe aerodynamic and structural dynamic representation. The theoretical background, computer program capabilities and limited correlation results are presented in this report. Correlation results using scale model wind tunnel results show that the analysis can adequately predict trends of vibration variations with airspeed and higher harmonic control effects. Predictions of absolute values of vibration levels were found to be very sensitive to modal characteristics and results were not representative of measured values.

  20. Fabrication of graphene/Fe{sub 3}O{sub 4}@polythiophene nanocomposite and its application in the magnetic solid-phase extraction of polycyclic aromatic hydrocarbons from environmental water samples

    Energy Technology Data Exchange (ETDEWEB)

    Mehdinia, Ali, E-mail: mehdinia@inio.ac.ir [Department of Marine Science, Iranian National Institute for Oceanography and Atmospheric Science, Tehran (Iran, Islamic Republic of); Khodaee, Nader; Jabbari, Ali [Department of Chemistry, Faculty of Science, K. N. Toosi University of Technology, Tehran (Iran, Islamic Republic of)

    2015-04-08

    Highlights: • G/Fe{sub 3}O{sub 4}@polythiophene as a novel sorbent for MSPE of PAHs. • Polythiopheneas an efficient modifier of G/Fe{sub 3}O{sub 4}. • G sheets can act as a “support” for the growth of Fe{sub 3}O{sub 4} nanoparticles. • G sheets can act as a “spacer” for the inhibition of NPs aggregation. - Abstract: Polythiophene (PT) was used as a surface modifier of graphene/Fe{sub 3}O{sub 4} (G/Fe{sub 3}O{sub 4}) composite to increase merit of it, and also overcome some limitations and disadvantages of using G/Fe{sub 3}O{sub 4} alone as solid phase extraction (SPE) sorbent. An in-situ chemical polymerization method was employed to prepare G/Fe{sub 3}O{sub 4}@PT nanocomposites. Application of this newly designed material in the magnetic SPE (MSPE) of polycyclic aromatic hydrocarbons (PAHs), as model analytes, in the environmental water samples was investigated. The characterization of the hybrid material was performed using transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray analysis, Fourier transform-infrared (FT-IR) spectroscopy and vibrating sample magnetometry. Seven important parameters, affecting the extraction efficiency of PAHs, including: amount of adsorbent, adsorption and desorption times, type and volume of the eluent solvent, initial sample volume and salt content of the sample were evaluated. The optimum extraction conditions were obtained as: 4 min for extraction time, 20 mg for sorbent amount, 100 mL for initial sample volume, toluene as desorption solvent, 0.6 mL for desorption solvent volume, 6 min for desorption time and 30% (w/v) for NaCl concentration. Good performance data were obtained at the optimized conditions. Detection limits were in the range of 0.009–0.020 μg L{sup −1} in the real matrix. The calibration curves were linear over the concentration ranges from 0.03 to 80 μg L{sup −1} with correlation coefficients (R{sup 2}) between 0.995 and 0.998 for all the analytes

  1. Gearbox Tooth Cut Fault Diagnostics Using Acoustic Emission and Vibration Sensors — A Comparative Study

    Directory of Open Access Journals (Sweden)

    Yongzhi Qu

    2014-01-01

    Full Text Available In recent years, acoustic emission (AE sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance.

  2. Gearbox Tooth Cut Fault Diagnostics Using Acoustic Emission and Vibration Sensors — A Comparative Study

    Science.gov (United States)

    Qu, Yongzhi; He, David; Yoon, Jae; Van Hecke, Brandon; Bechhoefer, Eric; Zhu, Junda

    2014-01-01

    In recent years, acoustic emission (AE) sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance. PMID:24424467

  3. Gearbox tooth cut fault diagnostics using acoustic emission and vibration sensors--a comparative study.

    Science.gov (United States)

    Qu, Yongzhi; He, David; Yoon, Jae; Van Hecke, Brandon; Bechhoefer, Eric; Zhu, Junda

    2014-01-14

    In recent years, acoustic emission (AE) sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance.

  4. High force vibration testing with wide frequency range

    Science.gov (United States)

    Romero, Edward F.; Jepsen, Richard A.; Gregory, Danny Lynn

    2013-04-02

    A shaker assembly for vibration testing includes first and second shakers, where the first shaker includes a piezo-electric material for generating vibration. A support structure permits a test object to be supported for vibration of the test object by both shakers. An input permits an external vibration controller to control vibration of the shakers.

  5. Hand-arm vibration syndrome and dose-response relation for vibration induced white finger among quarry drillers and stonecarvers. Italian Study Group on Physical Hazards in the Stone Industry.

    Science.gov (United States)

    Bovenzi, M

    1994-09-01

    To investigate the occurrence of disorders associated with the hand arm vibration syndrome in a large population of stone workers in Italy. The dose-response relation for vibration induced white finger (VWF) was also studied. The study population consisted of 570 quarry drillers and stonecarvers exposed to vibration and 258 control stone workers who performed only manual activity. Each subject was interviewed with health and workplace assessment questionnaires. Sensorineural and VWF disorders were staged according to the Stockholm workshop scales. Vibration was measured on a representative sample of percussive and rotary tools. The 8 h energy equivalent frequency weighted acceleration (A (8)) and lifetime vibration doses were calculated for each of the exposed stone workers. Sensorineural and musculoskeletal symptoms occurred more frequently in the workers exposed to vibration than in the controls, but trend statistics did not show a linear exposure-response relation for these disorders. The prevalence of VWF was found to be 30.2% in the entire group exposed to vibration. Raynaud's phenomenon was discovered in 4.3% of the controls. VWF was strongly associated with exposure to vibration and a monotonic dose-response relation was found. According to the exposure data of this study, the expected percentage of stone workers affected with VWF tends to increase roughly in proportion to the square root of A(8) (for a particular exposure period) or in proportion to the square root of the duration of exposure (for a constant magnitude of vibration). Even although limited to a specific work situation, the dose-response relation for VWF estimated in this study suggests a time dependency such that halving the years of exposure allows a doubling of the energy equivalent vibration. According to these findings, the vibration exposure levels currently under discussion within the European Community seem to represent reasonable exposure limits for the protection of workers against

  6. Experimental Research on Vibration Fatigue of CFRP and Its Influence Factors Based on Vibration Testing

    OpenAIRE

    Fan, Zhengwei; Jiang, Yu; Zhang, Shufeng; Chen, Xun

    2017-01-01

    A new research method based on vibration testing for the vibration fatigue of FRP was proposed in this paper. Through the testing on a closed-loop controlled vibration fatigue test system, the vibration fatigue phenomenon of typical carbon-fiber-reinforced plastic (CFRP) cantilevered laminate specimens was carefully studied. Moreover, a method based on the frequency response function was proposed to monitor the fatigue damage accumulation of specimens. On the basis of that, the influence fact...

  7. Vibrational dynamics of crystalline L-alanine

    Energy Technology Data Exchange (ETDEWEB)

    Bordallo, H.N.; Eckert, J. [Los Alamos National Lab., NM (United States); Barthes, M. [Univ. Montpellier II (France)

    1997-11-01

    The authors report a new, complete vibrational analysis of L-alanine and L-alanine-d{sub 4} which utilizes IINS intensities in addition to frequency information. The use of both isotopomers resulted in a self-consistent force field for and assignment of the molecular vibrations in L-alanine. Some details of the calculation as well as a comparison of calculated and observed IINS spectra are presented. The study clarifies a number of important issues on the vibrational dynamics of this molecule and presents a self-consistent force field for the molecular vibrations in crystalline L-alanine.

  8. Analysis of potential helicopter vibration reduction concepts

    Science.gov (United States)

    Landgrebe, A. J.; Davis, M. W.

    1985-01-01

    Results of analytical investigations to develop, understand, and evaluate potential helicopter vibration reduction concepts are presented in the following areas: identification of the fundamental sources of vibratory loads, blade design for low vibration, application of design optimization techniques, active higher harmonic control, blade appended aeromechanical devices, and the prediction of vibratory airloads. Primary sources of vibration are identified for a selected four-bladed articulated rotor operating in high speed level flight. The application of analytical design procedures and optimization techniques are shown to have the potential for establishing reduced vibration blade designs through variations in blade mass and stiffness distributions, and chordwise center-of-gravity location.

  9. Customized DSP-based vibration measurement for wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    LaWhite, N.E.; Cohn, K.E. [Second Wind Inc., Somerville, MA (United States)

    1996-12-31

    As part of its Advanced Distributed Monitoring System (ADMS) project funded by NREL, Second Wind Inc. is developing a new vibration measurement system for use with wind turbines. The system uses low-cost accelerometers originally designed for automobile airbag crash-detection coupled with new software executed on a Digital Signal Processor (DSP) device. The system is envisioned as a means to monitor the mechanical {open_quotes}health{close_quotes} of the wind turbine over its lifetime. In addition the system holds promise as a customized emergency vibration detector. The two goals are very different and it is expected that different software programs will be executed for each function. While a fast Fourier transform (FFT) signature under given operating conditions can yield much information regarding turbine condition, the sampling period and processing requirements make it inappropriate for emergency condition monitoring. This paper briefly reviews the development of prototype DSP and accelerometer hardware. More importantly, it reviews our work to design prototype vibration alarm filters. Two-axis accelerometer test data from the experimental FloWind vertical axis wind turbine is analyzed and used as a development guide. Two levels of signal processing are considered. The first uses narrow band pre-processing filters at key fundamental frequencies such as the 1P, 2P and 3P. The total vibration energy in each frequency band is calculated and evaluated as a possible alarm trigger. In the second level of signal processing, the total vibration energy in each frequency band is further decomposed using the two-axis directional information. Directional statistics are calculated to differentiate between linear translations and circular translations. After analyzing the acceleration statistics for normal and unusual operating conditions, the acceleration processing system described could be used in automatic early detection of fault conditions. 9 figs.

  10. [Study on the vibrational spectra and XRD characters of Huanglong jade from Longling County, Yunnan Province].

    Science.gov (United States)

    Pei, Jing-cheng; Fan, Lu-wei; Xie, Hao

    2014-12-01

    Based on the conventional test methods, the infrared absorption spectrum, Raman spectrum and X-ray diffraction (XRD) were employed to study the characters of the vibration spectrum and mineral composition of Huanglong jade. The testing results show that Huanglong jade shows typical vibrational spectrum characteristics of quartziferous jade. The main infrared absorption bands at 1162, 1076, 800, 779, 691, 530 and 466 cm(-1) were induced by the asymmetric stretching vibration, symmetrical stretching vibration and bending vibration of Si-O-Si separately. Especially the absorption band near 800 cm(-1) is split, which indicates that Huanglong jade has good crystallinity. In Raman spectrum, the main strong vibration bands at 463 and 355 cm(-1) were attributed to bending vibration of Si-O-Si. XRD test confirmed that Quartz is main mineral composition of Huanglong jade and there is a small amount of hematite in red color samples which induced the red color of Huanglong jade. This is the first report on the infrared, Raman and XRD spectra feature of Huanglong jade. It will provide a scientific basis for the identification, naming and other research for huanglong jade.

  11. Vibration fatigue using modal decomposition

    Science.gov (United States)

    Mršnik, Matjaž; Slavič, Janko; Boltežar, Miha

    2018-01-01

    Vibration-fatigue analysis deals with the material fatigue of flexible structures operating close to natural frequencies. Based on the uniaxial stress response, calculated in the frequency domain, the high-cycle fatigue model using the S-N curve material data and the Palmgren-Miner hypothesis of damage accumulation is applied. The multiaxial criterion is used to obtain the equivalent uniaxial stress response followed by the spectral moment approach to the cycle-amplitude probability density estimation. The vibration-fatigue analysis relates the fatigue analysis in the frequency domain to the structural dynamics. However, once the stress response within a node is obtained, the physical model of the structure dictating that response is discarded and does not propagate through the fatigue-analysis procedure. The structural model can be used to evaluate how specific dynamic properties (e.g., damping, modal shapes) affect the damage intensity. A new approach based on modal decomposition is presented in this research that directly links the fatigue-damage intensity with the dynamic properties of the system. It thus offers a valuable insight into how different modes of vibration contribute to the total damage to the material. A numerical study was performed showing good agreement between results obtained using the newly presented approach with those obtained using the classical method, especially with regards to the distribution of damage intensity and critical point location. The presented approach also offers orders of magnitude faster calculation in comparison with the conventional procedure. Furthermore, it can be applied in a straightforward way to strain experimental modal analysis results, taking advantage of experimentally measured strains.

  12. Gel performance in rheology and profile control under low-frequency vibration: coupling application of physical and chemical EOR techniques.

    Science.gov (United States)

    Zheng, Li Ming; Pu, Chun Sheng; Liu, Jing; Ma, Bo; Khan, Nasir

    2017-01-01

    Flowing gel plugging and low-frequency vibration oil extraction technology have been widely applied in low-permeability formation. High probability of overlapping in action spheres of two technologies might lead to poor operating efficiency during gel injection. Study on flowing gel rheological properties under low-frequency vibration was essential, which was carried out indoor with viscosity measurement. Potential dynamic mechanisms were analyzed for the rheological variation. Under low-frequency vibration, gel rheological properties were found to be obviously influenced, with vibration delaying gel cross-linking in induction period, causing a two-stage gel viscosity change in acceleration period, and decreasing gel strength in stable period. Surface of gel system under vibration presented different fluctuating phenomenon from initial harmonic vibrating to heterogeneous fluctuating (droplet separation might appear) to final harmonic vibrating again. Dynamic displacement in unconsolidated sand pack revealed that low-frequency vibration during gel injection might be a measure to achieve deep profile control, with the gel injection depth increased by 65.8 % compared with the vibration-free sample. At last, suggestions for field test were given in the paper to achieve lower injection friction and better gel plugging efficiency.

  13. Nonlinear vibration absorption for a flexible arm via a virtual vibration absorber

    Science.gov (United States)

    Bian, Yushu; Gao, Zhihui

    2017-07-01

    A semi-active vibration absorption method is put forward to attenuate nonlinear vibration of a flexible arm based on the internal resonance. To maintain the 2:1 internal resonance condition and the desirable damping characteristic, a virtual vibration absorber is suggested. It is mathematically equivalent to a vibration absorber but its frequency and damping coefficients can be readily adjusted by simple control algorithms, thereby replacing those hard-to-implement mechanical designs. Through theoretical analyses and numerical simulations, it is proven that the internal resonance can be successfully established for the flexible arm, and the vibrational energy of flexible arm can be transferred to and dissipated by the virtual vibration absorber. Finally, experimental results are presented to validate the theoretical predictions. Since the proposed method absorbs rather than suppresses vibrational energy of the primary system, it is more convenient to reduce strong vibration than conventional active vibration suppression methods based on smart material actuators with limited energy output. Furthermore, since it aims to establish an internal vibrational energy transfer channel from the primary system to the vibration absorber rather than directly respond to external excitations, it is especially applicable for attenuating nonlinear vibration excited by unpredictable excitations.

  14. Vibrational spectroscopy of Cm–C/Cb–Cb stretching vibrations of ...

    Indian Academy of Sciences (India)

    operator which conveniently describes stretching vibrations of biomolecules. For a copper tetramesityl porphyrin molecule, the higher excited vibrational levels are calculated by applying the U(2) algebraic approach. Keywords. Lie algebraic techniques; vibrational spectra; copper tetramesityl porphyrin. PACS Nos 31.65.

  15. Vibrational Spectroscopy of Chromatographic Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Jeanne E. Pemberton

    2011-03-10

    Chromatographic separations play a central role in DOE-supported fundamental research related to energy, biological systems, the environment, and nuclear science. The overall portfolio of research activities in the Separations and Analysis Program within the DOE Office of Basic Energy Sciences includes support for activities designed to develop a molecular-level understanding of the chemical processes that underlie separations for both large-scale and analytical-scale purposes. The research effort funded by this grant award was a continuation of DOE-supported research to develop vibrational spectroscopic methods to characterize the interfacial details of separations processes at a molecular level.

  16. Introduction to vibrations and waves

    CERN Document Server

    Pain, H John

    2015-01-01

    Based on the successful multi-edition book "The Physics ofVibrations and Waves" by John Pain, the authors carry overthe simplicity and logic of the approach taken in the originalfirst edition with its focus on the patterns underlying andconnecting so many aspects of physical behavior, whilst bringingthe subject up-to-date so it is relevant to teaching in the21st century.The transmission of energy by wave propagation is a key conceptthat has applications in almost every branch of physics withtransmitting mediums essentially acting as a continuum of coupledoscillators. The characterization of t

  17. Vibration diagnostics instrumentation for ILC

    Energy Technology Data Exchange (ETDEWEB)

    Bertolini, A.

    2007-06-15

    The future e{sup -}e{sup +} 500 GeV International Linear Collider will rely on unprecedented nanometer scale particle beam size at the interaction point, in order to achieve the design luminosity. Tight tolerances on static and dynamic alignment of the accelerator cavities and optical components are demanded to transport and focus the high energy electron and positron beams with reasonable position jitter and low emittance. A brief review of techniques and devices evaluated and developed so far for the vibration diagnostics of the machine is presented in this paper. (orig.)

  18. Monothiodibenzoylmethane: Structural and vibrational assignments

    DEFF Research Database (Denmark)

    Hansen, Bjarke Knud Vilster; Gorski, Alexander; Posokhov, Yevgen

    2007-01-01

    The vibrational structure of the title compound (1,3-diphenyl-3-thioxopropane-1-one, TDBM) was studied by a variety of experimental and theoretical methods. The stable ground state configuration of TDBM was investigated by IR absorption measurements in different media, by LD polarization spectros...... to an “open”, non-chelated enethiol form (t-TCC), thereby supporting the previous conclusions by Posokhov et al. No obvious indications of the contribution of other forms to the observed spectra could be found....

  19. Vibrational Locomotion Enabling Subsurface Exploration of Unconsolidated Regolith Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The idea of vibrational locomotion is based on vibrational-fluidization in ISRU reactor systems, which has proven very effective for regolith mixing. The vibrating...

  20. DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2006-01-17

    The objective of this program is to develop a system to both monitor the vibration of a bottomhole assembly, and to adjust the properties of an active damper in response to these measured vibrations. Phase I of this program, which entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype, was completed on May 31, 2004. The principal objectives of Phase II are: more extensive laboratory testing, including the evaluation of different feedback algorithms for control of the damper; design and manufacture of a field prototype system; and, testing of the field prototype in drilling laboratories and test wells. Work during this quarter centered on the testing of the rebuilt laboratory prototype and its conversion into a version that will be operable in the drilling tests at TerraTek Laboratories. In addition, formations for use in these tests were designed and constructed, and a test protocol was developed. The change in scope and no-cost extension of Phase II to January, 2006, described in our last report, were approved. The tests are scheduled to be run during the week of January 23, and should be completed before the end of the month.

  1. Chaotic vibrations of heated plates

    Science.gov (United States)

    Fermen-Coker, Muge

    1998-12-01

    In recent years, the investigation of dynamical behavior of plates under thermal loads has become important due to the high temperatures reached on external skin panels of hypersonic vehicles. It has been shown by other researchers that the skin panels may encounter chaotic vibrations about their thermally buckled positions. In this research, the chaotic vibrations of simply supported plates under thermal and sinusoidal excitation is studied in order to predict the vibratory behavior of a representative class of such skin panels. A method for the development of equations of motion, that forms a foundation for further investigation of the response of elastic panels under general thermal, mechanical and aerodynamic loading and various boundary conditions, is presented and discussed. The boundaries of regular and chaotic regions of motion are defined and the sensitivity of these boundaries to changes in design parameters is explored for the purpose of developing useful design criteria. The onset of chaos is predicted through the computation of Lyapunov exponents. The sensitivity of Lyapunov exponent calculations to the choice of numerical method of integration, numerical precision and the magnitude of coefficients as functions of design variables, is discussed. The effects of thermal moment, thermal buckling, amplitude and frequency of excitation, damping, thickness and length to width ratio of panels on the onset of chaos is studied. The results of the research are presented as a contribution to the panel design of hypersonic vehicles.

  2. Time-resolved vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tokmakoff, Andrei [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Champion, Paul [Northeastern Univ., Boston, MA (United States); Heilweil, Edwin J. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Nelson, Keith A. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Ziegler, Larry [Boston Univ., MA (United States)

    2009-05-14

    This document contains the Proceedings from the 14th International Conference on Time-Resolved Vibrational Spectroscopy, which was held in Meredith, NH from May 9-14, 2009. The study of molecular dynamics in chemical reaction and biological processes using time-resolved spectroscopy plays an important role in our understanding of energy conversion, storage, and utilization problems. Fundamental studies of chemical reactivity, molecular rearrangements, and charge transport are broadly supported by the DOE's Office of Science because of their role in the development of alternative energy sources, the understanding of biological energy conversion processes, the efficient utilization of existing energy resources, and the mitigation of reactive intermediates in radiation chemistry. In addition, time-resolved spectroscopy is central to all fiveof DOE's grand challenges for fundamental energy science. The Time-Resolved Vibrational Spectroscopy conference is organized biennially to bring the leaders in this field from around the globe together with young scientists to discuss the most recent scientific and technological advances. The latest technology in ultrafast infrared, Raman, and terahertz spectroscopy and the scientific advances that these methods enable were covered. Particular emphasis was placed on new experimental methods used to probe molecular dynamics in liquids, solids, interfaces, nanostructured materials, and biomolecules.

  3. Comparison of different ultrasonic vibration modes for post removal.

    Science.gov (United States)

    Braga, Neilor Mateus Antunes; Silva, Juliana Monteiro da; Carvalho-Júnior, Jacy Ribeiro de; Ferreira, Raquel Conceição; Saquy, Paulo César; Brito-Júnior, Manoel

    2012-01-01

    This in vitro study compared different ultrasonic vibration modes for intraradicular cast post removal. The crowns of 24 maxillary canines were removed, the roots were embedded in acrylic resin blocks, and the canals were treated endodontically. The post holes were prepared and root canal impressions were taken with self-cured resin acrylic. After casting, the posts were cemented with zinc phosphate cement. The samples were randomly distributed into 3 groups (n=8): G1: no ultrasonic vibration (control); G2: tip of the ultrasonic device positioned perpendicularly to core surface and close to the incisal edge; and G3: tip of the ultrasonic device positioned perpendicularly to core surface at cervical region, close to the line of cementation. An Enac OE-5 ultrasound unit with an ST-09 tip was used. All samples were submitted to the tensile test using an universal testing machine at a crosshead speed of 1 mm/min. Data were subjected to one-way ANOVA and Tukey's post-hoc tests (α=0.05). Mean values of the load to dislodge the posts (MPa) were: G1 = 4.6 (± 1.4) A; G2 = 2.8 (± 0.9) B, and G3= 0.9 (± 0.3) C. Therefore, the ultrasonic vibration applied with the tip of device close to the core's cervical area showed higher ability to reduce the retention of cast post to root canal.

  4. Online Monitoring and Analysis of Hydroabrasive Cutting by Vibration

    Directory of Open Access Journals (Sweden)

    Sergej Hloch

    2013-01-01

    Full Text Available The paper deals with the investigation of accompanying physical process, vibration, arising from the abrasive waterjet cutting of stainless steel. Samples of the square cross-section with the use of preplanned range of technological factors were cut. During the cutting of target material AISI 309 vibration by piezoelectrical accelerometers PCB IMI 607 A11 was recorded. The accelerometers were oriented perpendicular to the direction of the cut. Scanned data were processed through a virtual instrument created in LabVIEW 6.8. Sampling frequency of the recorded signal was 30 kHz. Investigated was development of the RMS value in particular frequencies. In order to confirm hypothetical assumptions about direct relation between vibration emission and surface quality, further experiment will be done. Current results are possible used for detection of defects during hydroabrasive cutting of materials, in case of focusing tube fracture, orifice damage in the cutting head, in case of fragile material cutting by means of controlled penetration.

  5. Vibration-based monitoring and diagnostics using compressive sensing

    Science.gov (United States)

    Ganesan, Vaahini; Das, Tuhin; Rahnavard, Nazanin; Kauffman, Jeffrey L.

    2017-04-01

    Vibration data from mechanical systems carry important information that is useful for characterization and diagnosis. Standard approaches rely on continually streaming data at a fixed sampling frequency. For applications involving continuous monitoring, such as Structural Health Monitoring (SHM), such approaches result in high volume data and rely on sensors being powered for prolonged durations. Furthermore, for spatial resolution, structures are instrumented with a large array of sensors. This paper shows that both volume of data and number of sensors can be reduced significantly by applying Compressive Sensing (CS) in vibration monitoring applications. The reduction is achieved by using random sampling and capitalizing on the sparsity of vibration signals in the frequency domain. Preliminary experimental results validating CS-based frequency recovery are also provided. By exploiting the sparsity of mode shapes, CS can also enable efficient spatial reconstruction using fewer spatially distributed sensors. CS can thereby reduce the cost and power requirement of sensing as well as streamline data storage and processing in monitoring applications. In well-instrumented structures, CS can enable continued monitoring in case of sensor or computational failures.

  6. Vibrational relaxation of the bending mode of HDO in liquid D2O.

    Science.gov (United States)

    Bodis, Pavol; Larsen, Olaf F A; Woutersen, Sander

    2005-06-23

    The vibrational relaxation of the bending mode of HDO in liquid D2O has been studied using time-resolved mid-infrared pump-probe spectroscopy. At short delays, the transient spectrum clearly shows the v = 1 --> 2 induced absorption and v = 1 --> 0 bleaching and stimulated emission, whereas at long delays, the transient spectrum is dominated by the spectral changes caused by the temperature increase in the sample after vibrational relaxation. From the decay of the v = 1 --> 2 induced absorption, we obtain an estimate of 390 +/- 50 fs for the vibrational lifetime, in surprisingly good agreement with recent theoretical predictions. In the v = 0 --> 1 frequency region, the decay of the absorption change involves a second, slower component, which suggests that after vibrational relaxation the system is not yet in thermal equilibrium.

  7. Photo-electromotive-force from vibrating speckled pattern of light on photorefractive CdTe:V

    Science.gov (United States)

    Santos, T. O.; Launay, J. C.; Frejlich, J.

    2008-04-01

    We report the use of the photo-electromotive force (photo-emf) effect produced by a vibrating speckle pattern of light, generated by laser radiation at 1064nm, in the volume of a photorefractive vanadium doped CdTe crystal. This effect is used to measure the sample's photocondutivity and the vibration amplitude of the pattern of light. When the vibrations are much faster than the photorefractive material reponse time the photocurrent is independent of the response time. The theoretical model predicts a maximum value for the first temporal harmonic term of the photocurrent at a fixed value for the vibration amplitude-to-speckle size ratio. This prediction was experimentally confirmed and this maximum can be used to calibrate the setup in order to facilitate practical applications.

  8. Broadband infrared vibrational nano-spectroscopy using thermal blackbody radiation.

    Science.gov (United States)

    O'Callahan, Brian T; Lewis, William E; Möbius, Silke; Stanley, Jared C; Muller, Eric A; Raschke, Markus B

    2015-12-14

    Infrared vibrational nano-spectroscopy based on scattering scanning near-field optical microscopy (s-SNOM) provides intrinsic chemical specificity with nanometer spatial resolution. Here we use incoherent infrared radiation from a 1400 K thermal blackbody emitter for broadband infrared (IR) nano-spectroscopy. With optimized interferometric heterodyne signal amplification we achieve few-monolayer sensitivity in phonon polariton spectroscopy and attomolar molecular vibrational spectroscopy. Near-field localization and nanoscale spatial resolution is demonstrated in imaging flakes of hexagonal boron nitride (hBN) and determination of its phonon polariton dispersion relation. The signal-to-noise ratio calculations and analysis for different samples and illumination sources provide a reference for irradiance requirements and the attainable near-field signal levels in s-SNOM in general. The use of a thermal emitter as an IR source thus opens s-SNOM for routine chemical FTIR nano-spectroscopy.

  9. Enriched vibrational resonance in certain discrete systems

    Indian Academy of Sciences (India)

    We wish to report the occurrence of vibrational resonance in certain discrete systems like sine square map and sine circle map, in a unique fashion, comprising of multiple resonant peaks which pave the way for enrichment. As the systems of our choice are capable of exhibiting vibrational resonance behaviour unlike the ...

  10. Enriched vibrational resonance in certain discrete systems

    Indian Academy of Sciences (India)

    system [10], bistable systems [1,11,12], time-delayed system [13] and also in a few low- dimensional maps [14] due to its ... the driving force, has attracted much attention in recent years. The study of vibrational ... odic trigonometric functions, one can expect the recurrence of multiple resonant peaks due to vibrational ...

  11. Modified Composite Struts Would Damp Vibrations

    Science.gov (United States)

    Chen, Gun-Shing; Dolgin, Benjamin P.

    1993-01-01

    Composite-material (fiber/matrix laminate) struts damping longitudinal vibrations fabricated more easily in proposed new design. Prior design described in "Composite Struts Would Damp Vibrations" (NPO-17914). New design similar except pattern of fibers includes rounded bends (instead of sharp bends) in fibers.

  12. Torsional vibrations of infinite composite poroelastic cylinders

    African Journals Online (AJOL)

    user

    Abstract. A study of torsional vibrations of an infinite composite poroelastic circular solid cylinder made of two different materials is made. The frequency equation of such torsional vibrations is obtained following analytical model based on Biot's theory of wave propagation in liquid saturated porous media. Each dilatation of ...

  13. Benefits of Spacecraft Level Vibration Testing

    Science.gov (United States)

    Gordon, Scott; Kern, Dennis L.

    2015-01-01

    NASA-HDBK-7008 Spacecraft Level Dynamic Environments Testing discusses the approaches, benefits, dangers, and recommended practices for spacecraft level dynamic environments testing, including vibration testing. This paper discusses in additional detail the benefits and actual experiences of vibration testing spacecraft for NASA Goddard Space Flight Center (GSFC) and Jet Propulsion Laboratory (JPL) flight projects. JPL and GSFC have both similarities and differences in their spacecraft level vibration test approach: JPL uses a random vibration input and a frequency range usually starting at 5 Hz and extending to as high as 250 Hz. GSFC uses a sine sweep vibration input and a frequency range usually starting at 5 Hz and extending only to the limits of the coupled loads analysis (typically 50 to 60 Hz). However, both JPL and GSFC use force limiting to realistically notch spacecraft resonances and response (acceleration) limiting as necessary to protect spacecraft structure and hardware from exceeding design strength capabilities. Despite GSFC and JPL differences in spacecraft level vibration test approaches, both have uncovered a significant number of spacecraft design and workmanship anomalies in vibration tests. This paper will give an overview of JPL and GSFC spacecraft vibration testing approaches and provide a detailed description of spacecraft anomalies revealed.

  14. The analysis of nonstationary vibration data

    Science.gov (United States)

    Piersol, Allan G.

    1987-01-01

    The general methodology for the analysis of arbitrary nonstationary random data is reviewed. A specific parametric model, called the product model, that has applications to space vehicle launch vibration data analysis is discussed. Illustrations are given using the nonstationary launch vibration data measured on the Space Shuttle orbiter vehicle.

  15. Quenching of self-excited vibrations

    NARCIS (Netherlands)

    Verhulst, F.

    2005-01-01

    Stable normal-mode vibrations in engineering can be undesirable and one of the possibilities for quenching these is by embedding the oscillator in an autoparametric system by coupling to a damped oscillator. There exists the possibility of destabilizing the undesirable vibrations by a suitable

  16. NOISE AND VIBRATION DAMPING FOR YACHT INTERIOR

    Directory of Open Access Journals (Sweden)

    Murat Aydın

    2016-12-01

    Full Text Available Vibration damping and sound insulation are essential for all vehicles. Because moving parts and external factors such as wind, tracks, etc. can cause vibration and noise. Wave which is a dynamic force, drive system and HVAC systems are the main vibration and noise generators in a vessel. These all can affect comfort level on board yachts. Different types of isolators and absorbers such as sylomer®, cork panels, etc. are used to reduce these effects. Comfort level on board yachts can be increased using these types of materials. Otherwise, discomfort of passenger and crew may increase. These materials not only reduce structure-borne and air-borne noise and vibrations from waves, air, engines, pumps, generators and HVAC systems but also protect vibration sensitive interior or fittings. Noise and vibration evaluation is an important issue for this reason. And, measurement tools must be used not only to minimize this problem but also fulfill the regulations such as “comfort class”. Besides, providing quiet and low vibration increases the costs too. From this point of view, this study aims to explain clearly how noise and vibration damping can be done in a yacht.

  17. Vibrational Stability of NLC Linac Accelerating Structure

    CERN Document Server

    Le Pimpec, F; Bowden, G B; Doyle, E; McKee, B; Seryi, Andrei; Redaelli, S; Adiga, S

    2002-01-01

    The vibration of components of the NLC linac, such as accelerating structures and girders, is being studied both experimentally and analytically. Various effects are being considered including structural resonances and vibration caused by cooling water in the accelerating structure. This paper reports the status of ongoing work.

  18. Communication: creation of molecular vibrational motions via the rotation-vibration coupling

    DEFF Research Database (Denmark)

    Shu, Chuan-Cun; Henriksen, Niels Engholm

    2015-01-01

    whereas a fast rotational excitation leads to a non-stationary vibrational motion. As a result, under field-free postpulse conditions, either a stretched stationary bond or a vibrating bond can be created due to the coupling between the rotational and vibrational degrees of freedom. The latter corresponds......Building on recent advances in the rotational excitation of molecules, we show how the effect of rotation-vibration coupling can be switched on in a controlled manner and how this coupling unfolds in real time after a pure rotational excitation. We present the first examination of the vibrational...... motions which can be induced via the rotation-vibration coupling after a pulsed rotational excitation. A time-dependent quantum wave packet calculation for the HF molecule shows how a slow (compared to the vibrational period) rotational excitation leads to a smooth increase in the average bond length...

  19. Modeling Displacement Measurement using Vibration Transducers

    Directory of Open Access Journals (Sweden)

    AGOSTON Katalin

    2014-05-01

    Full Text Available This paper presents some aspects regarding to small displacement measurement using vibration transducers. Mechanical faults, usages, slackness’s, cause different noises and vibrations with different amplitude and frequency against the normal sound and movement of the equipment. The vibration transducers, accelerometers and microphone are used for noise and/or sound and vibration detection with fault detection purpose. The output signal of the vibration transducers or accelerometers is an acceleration signal and can be converted to either velocity or displacement, depending on the preferred measurement parameter. Displacement characteristics are used to indicate when the machine condition has changed. There are many problems using accelerometers to measure position or displacement. It is important to determine displacement over time. To determinate the movement from acceleration a double integration is needed. A transfer function and Simulink model was determinate for accelerometers with capacitive sensing element. Using these models the displacement was reproduced by low frequency input.

  20. Passively damped vibration welding system and method

    Science.gov (United States)

    Tan, Chin-An; Kang, Bongsu; Cai, Wayne W.; Wu, Tao

    2013-04-02

    A vibration welding system includes a controller, welding horn, an anvil, and a passive damping mechanism (PDM). The controller generates an input signal having a calibrated frequency. The horn vibrates in a desirable first direction at the calibrated frequency in response to the input signal to form a weld in a work piece. The PDM is positioned with respect to the system, and substantially damps or attenuates vibration in an undesirable second direction. A method includes connecting the PDM having calibrated properties and a natural frequency to an anvil of an ultrasonic welding system. Then, an input signal is generated using a weld controller. The method includes vibrating a welding horn in a desirable direction in response to the input signal, and passively damping vibration in an undesirable direction using the PDM.

  1. High Energy Vibration for Gas Piping

    Science.gov (United States)

    Lee, Gary Y. H.; Chan, K. B.; Lee, Aylwin Y. S.; Jia, ShengXiang

    2017-07-01

    In September 2016, a gas compressor in offshore Sarawak has its rotor changed out. Prior to this change-out, pipe vibration study was carried-out by the project team to evaluate any potential high energy pipe vibration problems at the compressor’s existing relief valve downstream pipes due to process condition changes after rotor change out. This paper covers high frequency acoustic excitation (HFAE) vibration also known as acoustic induced vibration (AIV) study and discusses detailed methodologies as a companion to the Energy Institute Guidelines for the avoidance of vibration induced fatigue failure, which is a common industry practice to assess and mitigate for AIV induced fatigue failure. Such detailed theoretical studies can help to minimize or totally avoid physical pipe modification, leading to reduce offshore plant shutdown days to plant shutdowns only being required to accommodate gas compressor upgrades, reducing cost without compromising process safety.

  2. Deduction of structural information of interfacial proteins by combined vibrational spectroscopic methods.

    Science.gov (United States)

    Wang, Jie; Paszti, Zoltan; Clarke, Matthew L; Chen, Xiaoyun; Chen, Zhan

    2007-05-31

    We demonstrate both theoretically and experimentally that the combination of vibrational spectroscopic techniques on samples can be used to deduce more detailed structural information of interfacial proteins and peptides. Such an approach can be used to elucidate structures of proteins or peptides at interfaces, such as at the solid/liquid interface or in cell membranes. We also discuss that the controlled perturbations may provide more measured parameters for structural studies on such proteins and peptides. In this paper, we will demonstrate that optical spectroscopic techniques such as polarized Fourier transform infrared spectroscopy (FTIR), sum frequency generation (SFG) vibrational spectroscopy, and higher order nonlinear vibrational spectroscopies can be used to deduce different and complementary structural information of molecules at interfaces (e.g., orientation information of certain functional groups and secondary structures of interfacial proteins). Also, we believe that controlled perturbations on samples, such as variation of sample temperature, application of electrical fields, and alternation of substrate roughness, can provide more detailed information regarding the interfacial structures of proteins and peptides. The development of nonlinear vibrational spectroscopies, such as SFG and four-wave mixing vibrational spectroscopy, to examine interfacial protein and peptide structures, and introduction of external perturbations on samples should be able to substantially advance our knowledge in understanding structures and thus functions of proteins and peptides at interfaces.

  3. Superparamagnetic core-shells anchored onto graphene oxide grafted with phenylethyl amine as a nano-adsorbent for extraction and enrichment of organophosphorus pesticides from fruit, vegetable and water samples.

    Science.gov (United States)

    Mahpishanian, Shokouh; Sereshti, Hassan; Baghdadi, Majid

    2015-08-07

    A novel adsorbent composed of silica coated magnetic microparticles (Fe3O4@SiO2) and graphene oxide (GO) functionalized with phenylethyl amine (PEA) was synthesized and characterized using Fourier transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), and CHN elemental analysis techniques. The adsorbent (Fe3O4@SiO2@GO-PEA) was then used in a magnetic solid phase extraction (MSPE) of six organophosphorous pesticides (OPPs) including methyl parathion, fenitrothion, methidathion, ethion, methyl azinphos and coumaphos prior to gas chromatography-nitrogen phosphorus detection (GC-NPD). The fabricated adsorbent combines the advantages of superior adsorption capability of modified GO and magnetic separability of magnetite microparticles to provide high adsorption capacity, and easy isolation from sample solutions. The main experimental parameters affecting the extraction recovery of OPPs including extraction time, pH, adsorbent dosage, salt concentration, and desorption conditions were investigated and optimized. Under the optimal conditions, linear responses were obtained in the concentration range of 0.06-200μgL(-1) with the determination coefficients (R(2)) between 0.9945 and 0.9996. The limits of detection were from 0.02 to 0.1μgL(-1) and the intraday and inter-day relative standard deviations (RSDs) were less than 4.8 and 6.4%, respectively. The method was successfully applied for determination of the OPPs in apple, grape, pear, bell pepper, celery and water samples. The obtained recoveries were in the range of 90.4-108.0% (RSDs=1.9-6.6%, n=3) for fruits and vegetables, and 94.6-104.2% (RSDs=2.0-4.8%, n=3) for water samples. The excellent extraction performance of the adsorbent can be attributed to its structure characteristics where the phenyl rings of PEA grafted on the GO nanosheets are accessible to interact effectively with OPPs via delocalized π-electron system. Copyright © 2015 Elsevier B.V. All

  4. In-situ investigation of martensite formation in AISI 52100 bearing steel at sub-zero Celsius temperature

    DEFF Research Database (Denmark)

    Villa, Matteo; Hansen, Mikkel Fougt; Pantleon, Karen

    2013-01-01

    Martensite formation in AISI 52100 bearing steel at sub-zero Celsius temperature was investigated with Vibrating Sample Magnetometry. The investigation reports the stabilization of retained austenite in quenched samples during storage at room temperature and reveals the thermally activated nature...

  5. Damage-free vibrational spectroscopy of biological materials in the electron microscope.

    Science.gov (United States)

    Rez, Peter; Aoki, Toshihiro; March, Katia; Gur, Dvir; Krivanek, Ondrej L; Dellby, Niklas; Lovejoy, Tracy C; Wolf, Sharon G; Cohen, Hagai

    2016-03-10

    Vibrational spectroscopy in the electron microscope would be transformative in the study of biological samples, provided that radiation damage could be prevented. However, electron beams typically create high-energy excitations that severely accelerate sample degradation. Here this major difficulty is overcome using an 'aloof' electron beam, positioned tens of nanometres away from the sample: high-energy excitations are suppressed, while vibrational modes of energies <1 eV can be 'safely' investigated. To demonstrate the potential of aloof spectroscopy, we record electron energy loss spectra from biogenic guanine crystals in their native state, resolving their characteristic C-H, N-H and C=O vibrational signatures with no observable radiation damage. The technique opens up the possibility of non-damaging compositional analyses of organic functional groups, including non-crystalline biological materials, at a spatial resolution of ∼10 nm, simultaneously combined with imaging in the electron microscope.

  6. Analytical design and evaluation of an active control system for helicopter vibration reduction and gust response alleviation

    Science.gov (United States)

    Taylor, R. B.; Zwicke, P. E.; Gold, P.; Miao, W.

    1980-01-01

    An analytical study was conducted to define the basic configuration of an active control system for helicopter vibration and gust response alleviation. The study culminated in a control system design which has two separate systems: narrow band loop for vibration reduction and wider band loop for gust response alleviation. The narrow band vibration loop utilizes the standard swashplate control configuration to input controller for the vibration loop is based on adaptive optimal control theory and is designed to adapt to any flight condition including maneuvers and transients. The prime characteristics of the vibration control system is its real time capability. The gust alleviation control system studied consists of optimal sampled data feedback gains together with an optimal one-step-ahead prediction. The prediction permits the estimation of the gust disturbance which can then be used to minimize the gust effects on the helicopter.

  7. Carbon Nanotube Tape Vibrating Gyroscope

    Science.gov (United States)

    Tucker, Dennis Stephen (Inventor)

    2016-01-01

    A vibrating gyroscope includes a piezoelectric strip having length and width dimensions. The piezoelectric strip includes a piezoelectric material and carbon nanotubes (CNTs) substantially aligned and polled along the strip's length dimension. A spindle having an axis of rotation is coupled to the piezoelectric strip. The axis of rotation is parallel to the strip's width dimension. A first capacitance sensor is mechanically coupled to the spindle for rotation therewith. The first capacitance sensor is positioned at one of the strip's opposing ends and is spaced apart from one of the strip's opposing faces. A second capacitance sensor is mechanically coupled to the spindle for rotation therewith. The second capacitance sensor is positioned at another of the strip's opposing ends and is spaced apart from another of the strip's opposing faces. A voltage source applies an AC voltage to the piezoelectric strip.

  8. DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2005-04-27

    The objective of this program is to develop a system to both monitor the vibration of a bottomhole assembly, and to adjust the properties of an active damper in response to these measured vibrations. Phase I of this program, which entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype, was completed on May 31, 2004. The principal objectives of Phase II are: more extensive laboratory testing, including the evaluation of different feedback algorithms for control of the damper; design and manufacture of a field prototype system; and, testing of the field prototype in drilling laboratories and test wells. As a result of the lower than expected performance of the MR damper noted last quarter, several additional tests were conducted. These dealt with possible causes of the lack of dynamic range observed in the testing: additional damping from the oil in the Belleville springs; changes in properties of the MR fluid; and, residual magnetization of the valve components. Of these, only the last was found to be significant. By using a laboratory demagnetization apparatus between runs, a dynamic range of 10:1 was achieved for the damper, more than adequate to produce the needed improvements in drilling. Additional modeling was also performed to identify a method of increasing the magnetic field in the damper. As a result of the above, several changes were made in the design. Additional circuitry was added to demagnetize the valve as the field is lowered. The valve was located to above the Belleville springs to reduce the load placed upon it and offer a greater range of materials for its construction. In addition, to further increase the field strength, the coils were relocated from the mandrel to the outer housing. At the end of the quarter, the redesign was complete and new parts were on order. The project is approximately three months behind schedule at this time.

  9. Super-multiplex vibrational imaging

    Science.gov (United States)

    Wei, Lu; Chen, Zhixing; Shi, Lixue; Long, Rong; Anzalone, Andrew V.; Zhang, Luyuan; Hu, Fanghao; Yuste, Rafael; Cornish, Virginia W.; Min, Wei

    2017-04-01

    The ability to visualize directly a large number of distinct molecular species inside cells is increasingly essential for understanding complex systems and processes. Even though existing methods have successfully been used to explore structure-function relationships in nervous systems, to profile RNA in situ, to reveal the heterogeneity of tumour microenvironments and to study dynamic macromolecular assembly, it remains challenging to image many species with high selectivity and sensitivity under biological conditions. For instance, fluorescence microscopy faces a ‘colour barrier’, owing to the intrinsically broad (about 1,500 inverse centimetres) and featureless nature of fluorescence spectra that limits the number of resolvable colours to two to five (or seven to nine if using complicated instrumentation and analysis). Spontaneous Raman microscopy probes vibrational transitions with much narrower resonances (peak width of about 10 inverse centimetres) and so does not suffer from this problem, but weak signals make many bio-imaging applications impossible. Although surface-enhanced Raman scattering offers high sensitivity and multiplicity, it cannot be readily used to image specific molecular targets quantitatively inside live cells. Here we use stimulated Raman scattering under electronic pre-resonance conditions to image target molecules inside living cells with very high vibrational selectivity and sensitivity (down to 250 nanomolar with a time constant of 1 millisecond). We create a palette of triple-bond-conjugated near-infrared dyes that each displays a single peak in the cell-silent Raman spectral window; when combined with available fluorescent probes, this palette provides 24 resolvable colours, with the potential for further expansion. Proof-of-principle experiments on neuronal co-cultures and brain tissues reveal cell-type-dependent heterogeneities in DNA and protein metabolism under physiological and pathological conditions, underscoring the

  10. Review of Energy Harvesters Utilizing Bridge Vibrations

    Directory of Open Access Journals (Sweden)

    Farid Ullah Khan

    2016-01-01

    Full Text Available For health monitoring of bridges, wireless acceleration sensor nodes (WASNs are normally used. In bridge environment, several forms of energy are available for operating WASNs that include wind, solar, acoustic, and vibration energy. However, only bridge vibration has the tendency to be utilized for embedded WASNs application in bridge structures. This paper reports on the recent advancements in the area of vibration energy harvesters (VEHs utilizing bridge oscillations. The bridge vibration is narrowband (1 to 40 Hz with low acceleration levels (0.01 to 3.8 g. For utilization of bridge vibration, electromagnetic based vibration energy harvesters (EM-VEHs and piezoelectric based vibration energy harvesters (PE-VEHs have been developed. The power generation of the reported EM-VEHs is in the range from 0.7 to 1450000 μW. However, the power production by the developed PE-VEHs ranges from 0.6 to 7700 μW. The overall size of most of the bridge VEHs is quite comparable and is in mesoscale. The resonant frequencies of EM-VEHs are on the lower side (0.13 to 27 Hz in comparison to PE-VEHs (1 to 120 Hz. The power densities reported for these bridge VEHs range from 0.01 to 9539.5 μW/cm3 and are quite enough to operate most of the commercial WASNs.

  11. Simulation studies for multichannel active vibration control

    Science.gov (United States)

    Prakash, Shashikala; Balasubramaniam, R.; Praseetha, K. K.

    2003-10-01

    Traditional approach to vibration control uses passive techniques, which are relatively large, costly and ineffective at low frequencies. Active Vibration Control (AVC) is used to overcome these problems & in AVC additional sources (secondary) are used to cancel vibration from primary source based on the principle of superposition theorem Since the characteristics of the vibration source and environment are time varying, the AVC system must be adaptive. Adaptive systems have the ability to track time varying disturbances and provide optimal control over a much broader range of conditions than conventional fixed control systems. In multi channel AVC vibration fields in large dimensions are controlled & is more complicated. Therefore to actively control low frequency vibrations on large structures, multi channel AVC requires a control system that uses multiple secondary sources to control the vibration field simultaneously at multiple error sensor locations. The error criterion that can be directly measured is the sum of squares of outputs of number of sensors. The adaptive algorithm is designed to minimize this & the algorithm implemented is the "Multiple error LMS algorithm." The best known applications of multiple channel FXLMS algorithm is in real time AVC and system identification. More wider applications are in the control of propeller induced noise in flight cabin interiors. In the present paper the results of simulation studies carried out in MATLAB as well as on TMS320C32 DSP processor will be brought out for a two-channel case.

  12. Bevel Gearbox Fault Diagnosis using Vibration Measurements

    Directory of Open Access Journals (Sweden)

    Hartono Dennis

    2016-01-01

    Full Text Available The use of vibration measurementanalysis has been proven to be effective for gearbox fault diagnosis. However, the complexity of vibration signals observed from a gearbox makes it difficult to accurately detectfaults in the gearbox. This work is based on a comparative studyof several time-frequency signal processing methods that can be used to extract information from transient vibration signals containing useful diagnostic information. Experiments were performed on a bevel gearbox test rig using vibration measurements obtained from accelerometers. Initially, thediscrete wavelet transform was implementedfor vibration signal analysis to extract the frequency content of signal from the relevant frequency region. Several time-frequency signal processing methods werethen incorporated to extract the fault features of vibration signals and their diagnostic performances were compared. It was shown thatthe Short Time Fourier Transform (STFT could not offer a good time resolution to detect the periodicity of the faulty gear tooth due the difficulty in choosing an appropriate window length to capture the impulse signal. The Continuous Wavelet Transform (CWT, on the other hand, was suitable to detection of vibration transients generated by localized fault from a gearbox due to its multi-scale property. However, both methods still require a thorough visual inspection. In contrast, it was shown from the experiments that the diagnostic method using the Cepstrumanalysis could provide a direct indication of the faulty tooth without the need of a thorough visual inspection as required by CWT and STFT.

  13. A high pressure study of the eigenvectors of the infra-red active vibrational modes of crystalline adenosine.

    Science.gov (United States)

    Starkey, Carl A; Lee, Scott A; Anderson, Anthony

    2016-01-01

    High-pressure infrared spectroscopy has been used to study the eigenvectors and eigenvalues of the vibrational modes of crystalline adenosine at 298 K by evaluating the logarithmic derivative of the vibrational frequency with respect to pressure: [Formula: see text]. Crystalline samples of molecular materials such as adenosine have vibrational modes that are localized within a molecular unit ("internal" modes) as well as modes in which the molecular units vibrate against each other ("external" modes). The value of the logarithmic derivative is that it is a diagnostic probe of the nature of the eigenvector of these vibrational modes. Stretching modes, which are predominantly internal to the molecule, have low logarithmic derivatives while external modes have higher logarithmic derivatives. Particular attention is paid to modes in the 800-1000 cm(-1) range since modes in that region of the vibrational spectrum are found to be sensitive to the conformation of double-helical DNA. Since the sugar pucker is different for the various conformations of DNA, this fact suggests that these modes involve the motion of atoms in the sugar group. The vibrations of the hydrogen atoms are also of interest to study since the vibrational frequency of hydrogen atoms involved in hydrogen bonds has a negative pressure derivative. Such behavior clearly shows which hydrogen atoms are involved in hydrogen bonding.

  14. Effects of vibrational motion on core-level spectra of prototype organic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Uejio, Janel S.; Schwartz, Craig P.; Saykally, Richard J.; Prendergast, David

    2008-08-21

    A computational approach is presented for prediction and interpretation of core-level spectra of complex molecules. Applications are presented for several isolated organic molecules, sampling a range of chemical bonding and structural motifs. Comparison with gas phase measurements indicate that spectral lineshapes are accurately reproduced both above and below the ionization potential, without resort to ad hoc broadening. Agreement with experiment is significantly improved upon inclusion of vibrations via molecular dynamics sampling. We isolate and characterize spectral features due to particular electronic transitions enabled by vibrations, noting that even zero-point motion is sufficient in some cases.

  15. Terahertz mechanical vibrations in lysozyme: Raman spectroscopy vs modal analysis

    Science.gov (United States)

    Carpinteri, Alberto; Lacidogna, Giuseppe; Piana, Gianfranco; Bassani, Andrea

    2017-07-01

    The mechanical behaviour of proteins is receiving an increasing attention from the scientific community. Recently it has been suggested that mechanical vibrations play a crucial role in controlling structural configuration changes (folding) which govern proteins biological function. The mechanism behind protein folding is still not completely understood, and many efforts are being made to investigate this phenomenon. Complex molecular dynamics simulations and sophisticated experimental measurements are conducted to investigate protein dynamics and to perform protein structure predictions; however, these are two related, although quite distinct, approaches. Here we investigate mechanical vibrations of lysozyme by Raman spectroscopy and linear normal mode calculations (modal analysis). The input mechanical parameters to the numerical computations are taken from the literature. We first give an estimate of the order of magnitude of protein vibration frequencies by considering both classical wave mechanics and structural dynamics formulas. Afterwards, we perform modal analyses of some relevant chemical groups and of the full lysozyme protein. The numerical results are compared to experimental data, obtained from both in-house and literature Raman measurements. In particular, the attention is focused on a large peak at 0.84 THz (29.3 cm-1) in the Raman spectrum obtained analyzing a lyophilized powder sample.

  16. Membrane Vibration Analysis Above the Nyquist Limit with Fluorescence Videogrammetry

    Science.gov (United States)

    Dorrington, Adrian A.; Jones, Thomas W.; Danehy, Paul M.; Pappa, Richard S.

    2004-01-01

    A new method for generating photogrammetric targets by projecting an array of laser beams onto a membrane doped with fluorescent laser dye has recently been developed. In this paper we review this new fluorescence based technique, then proceed to show how it can be used for dynamic measurements, and how a short pulsed (10 ns) laser allows the measurement of vibration modes at frequencies several times the sampling frequency. In addition, we present experimental results showing the determination of fundamental and harmonic vibration modes of a drum style dye-doped polymer membrane tautly mounted on a 12-inch circular hoop and excited with 30 Hz and 62 Hz sinusoidal acoustic waves. The projected laser dot pattern was generated by passing the beam from a pulsed Nd:YAG laser though a diffractive optical element, and the resulting fluorescence was imaged with three digital video cameras, all of which were synchronized with a pulse and delay generator. Although the video cameras are capable of 240 Hz frame rates, the laser s output was limited to 30 Hz and below. Consequently, aliasing techniques were used to allow the measurement of vibration modes up to 186 Hz with a Nyquist limit of less than 15 Hz.

  17. Low cost subpixel method for vibration measurement

    Energy Technology Data Exchange (ETDEWEB)

    Ferrer, Belen [Department of Civil Engineering, Univ. Alicante P.O. Box, 99, 03080 Alicante (Spain); Espinosa, Julian; Perez, Jorge; Acevedo, Pablo; Mas, David [Inst. of Physics Applied to the Sciences and Technologies, Univ. Alicante P.O. Box, 99, 03080 Alicante (Spain); Roig, Ana B. [Department of Optics, Univ. Alicante P.O. Box, 99, 03080 Alicante (Spain)

    2014-05-27

    Traditional vibration measurement methods are based on devices that acquire local data by direct contact (accelerometers, GPS) or by laser beams (Doppler vibrometers). Our proposal uses video processing to obtain the vibration frequency directly from the scene, without the need of auxiliary targets or devices. Our video-vibrometer can obtain the vibration frequency at any point in the scene and can be implemented with low-cost devices, such as commercial cameras. Here we present the underlying theory and some experiments that support our technique.

  18. Reducing Transmitted Vibration Using Delayed Hysteretic Suspension

    Directory of Open Access Journals (Sweden)

    Lahcen Mokni

    2011-01-01

    Full Text Available Previous numerical and experimental works show that time delay technique is efficient to reduce transmissibility of vibration in a single pneumatic chamber by controlling the pressure in the chamber. The present work develops an analytical study to demonstrate the effectiveness of such a technique in reducing transmitted vibrations. A quarter-car model is considered and delayed hysteretic suspension is introduced in the system. Analytical predictions based on perturbation analysis show that a delayed hysteretic suspension enhances vibration isolation comparing to the case where the nonlinear damping is delay-independent.

  19. Review of magnetostrictive vibration energy harvesters

    Science.gov (United States)

    Deng, Zhangxian; Dapino, Marcelo J.

    2017-10-01

    The field of energy harvesting has grown concurrently with the rapid development of portable and wireless electronics in which reliable and long-lasting power sources are required. Electrochemical batteries have a limited lifespan and require periodic recharging. In contrast, vibration energy harvesters can supply uninterrupted power by scavenging useful electrical energy from ambient structural vibrations. This article reviews the current state of vibration energy harvesters based on magnetostrictive materials, especially Terfenol-D and Galfenol. Existing magnetostrictive harvester designs are compared in terms of various performance metrics. Advanced techniques that can reduce device size and improve performance are presented. Models for magnetostrictive devices are summarized to guide future harvester designs.

  20. Using consumer electronic devices to estimate whole-body vibration exposure.

    Science.gov (United States)

    Wolfgang, Rebecca; Burgess-Limerick, Robin

    2014-01-01

    The cost and complexity of commercially available devices for measuring whole-body vibration is a barrier to the systematic collection of the information required to manage this hazard at workplaces. The potential for a consumer electronic device to be used to estimate whole-body vibration was assessed by use of an accelerometer calibrator, and by collecting 42 simultaneous pairs of measurements from a fifth-generation iPod Touch and one of two gold standard vibration measurement devices (Svantech SV111 [Svantech, Warsaw, Poland] or Brüel & Kjær 4447 [Brüel & Kjær Sound & Vibration Measurement A/S, Nærum, Denmark]) while driving light vehicles on a variety of different roadway surfaces. While sampling rate limitations make the accelerometer data collected from the iPod Touch unsuitable for frequency analysis, the vibration amplitudes recorded are sufficiently accurate (errors less than 0.1 m/s(2)) to assist workplaces manage whole-body vibration exposures.

  1. Multivariate Chemical Image Fusion of Vibrational Spectroscopic Imaging Modalities

    Directory of Open Access Journals (Sweden)

    Aoife A. Gowen

    2016-07-01

    Full Text Available Chemical image fusion refers to the combination of chemical images from different modalities for improved characterisation of a sample. Challenges associated with existing approaches include: difficulties with imaging the same sample area or having identical pixels across microscopic modalities, lack of prior knowledge of sample composition and lack of knowledge regarding correlation between modalities for a given sample. In addition, the multivariate structure of chemical images is often overlooked when fusion is carried out. We address these challenges by proposing a framework for multivariate chemical image fusion of vibrational spectroscopic imaging modalities, demonstrating the approach for image registration, fusion and resolution enhancement of chemical images obtained with IR and Raman microscopy.

  2. Vibrational Cooling in A Cold Ion Trap: Vibrationally Resolved Photoelectron Spectroscopy of Cold C60- Anions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xue B.; Woo, Hin-koon; Wang, Lai S.

    2005-08-01

    We demonstrate vibrational cooling of anions via collisions with a background gas in an ion trap attached to a cryogenically controlled cold head (10 ? 400 K). Photoelectron spectra of vibrationally cold C60- anions, produced by electrospray ionization and cooled in the cold ion trap, have been obtained. Relative to spectra taken at room temperature, vibrational hot bands are completely eliminated, yielding well resolved vibrational structures and a more accurate electron affinity for neutral C60. The electron affinity of C60 is measured to be 2.683 ? 0.008 eV. The cold spectra reveal complicated vibrational structures for the transition to the C60 ground state due to the Jahn-Teller effect in the ground state of C60-. Vibrational excitations in the two Ag modes and eight Hg modes are observed, providing ideal data to assess the vibronic couplings in C60-.

  3. 14 CFR 23.251 - Vibration and buffeting.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration and buffeting. 23.251 Section 23... Requirements § 23.251 Vibration and buffeting. There must be no vibration or buffeting severe enough to result in structural damage, and each part of the airplane must be free from excessive vibration, under any...

  4. Whole-body vibration dosage alters leg blood flow

    NARCIS (Netherlands)

    Lythgo, Noel; Eser, Prisca; de Groot, Patricia; Galea, Mary

    The effect of whole-body vibration dosage on leg blood flow was investigated. Nine healthy young adult males completed a set of 14 random vibration and non-vibration exercise bouts whilst squatting on a Galileo 900 plate. Six vibration frequencies ranging from 5 to 30 Hz (5 Hz increments) were used

  5. 14 CFR 25.251 - Vibration and buffeting.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration and buffeting. 25.251 Section 25... Vibration and buffeting. (a) The airplane must be demonstrated in flight to be free from any vibration and... airplane must be demonstrated in flight to be free from excessive vibration under any appropriate speed and...

  6. Vibration improved the fluidity of aluminum alloys in thin wall ...

    African Journals Online (AJOL)

    user

    The effect of vibration is quantified and incorporated into the fluidity model, such that the velocity with and without vibration can be considered in the fluidity model. High pouring temperature aluminum alloy in thin wall investment casting, fluidity characteristic is improved by application of vibration. Keywords: Vibration ...

  7. Putting a damper on drilling's bad vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Jardine, S. (Sedco forex, Montrouge (France)); Malone, D. (Anadrill, Sugar Land, TX (United States)); Sheppard, M. (Schlumberger Cambridge Research, Cambridge (United Kingdom))

    1994-01-01

    Harmful drilling vibrations are costing the industry dearly. Three main vibration types (axial, torsional and transverse) are explained and its causes discussed. Technology exists to eliminate most vibrations, but requires more systematic deployment than is usual. Hardware that eliminates vibrations is reviewed, including downhole shock measurement, torque feedback shock guards and antiwhirl bits. 9 figs., 11 refs.

  8. A novel vibration sensor based on phase grating interferometry

    Science.gov (United States)

    Li, Qian; Liu, Xiaojun; Zhao, Li; Lei, Zili; Lu, Zhen; Guo, Lei

    2017-05-01

    Vibration sensors with high accuracy and reliability are needed urgently for vibration measurement. In this paper a vibration sensor with nanometer resolution is developed. This sensor is based on the principle of phase grating interference for displacement measurement and spatial polarization phase-shift interference technology, and photoelectric counting and A/D signal subdivision are adopted for vibration data output. A vibration measurement system consisting of vibration actuator and displacement adjusting device has been designed to test the vibration sensor. The high resolution and high reliability of the sensor are verified through a series of comparison experiments with Doppler interferometer.

  9. Optimal vibration stimulation to the neck extensor muscles using hydraulic vibrators to shorten saccadic reaction time.

    Science.gov (United States)

    Fujiwara, Katsuo; Kunita, Kenji; Furune, Naoe; Maeda, Kaoru; Asai, Hitoshi; Tomita, Hidehito

    2006-09-01

    Optimal vibration stimulation to the neck extensor muscles using hydraulic vibrators to shorten the saccadic reaction time was examined. Subjects were 14 healthy young adults. Visual targets (LEDs) were located 10 degrees left and right of a central point. The targets were alternately lit for random durations of 2-4 seconds in a resting neck condition and various vibration conditions, and saccadic reaction times were measured. Vibration amplitude was 0.5 mm in every condition. The upper trapezius muscles were vibrated at 40, 60, 80, and 100 Hz in a sub-maximum stretch condition in which the muscles were stretched at 70% of maximum stretch. In addition, the muscles were vibrated at 60 Hz with the muscles maximally stretched, with 70% vertical pressure without stretching, and with vibration applied to the skin in the same area as the muscle vibration. At 60, 80, and 100 Hz at 70% maximum stretch, saccadic reaction time shortened significantly compared with the resting neck condition. However, no significant difference in the reaction time was observed among the frequencies. The saccadic reaction times in the maximum stretch condition, muscle pressure condition, and skin contact condition did not differ significantly from that in the resting neck condition. Vibration stimulation to the trapezius with 60-100 Hz frequencies at 0.5 mm amplitude in the sub-maximum stretch condition was effective for shortening saccadic reaction time. The main mechanism appears to be Ia information originating from the muscle spindle.

  10. Vibrational Excitation Can Control Tropospheric Chemistry

    National Research Council Canada - National Science Library

    Geoffrey Tyndall

    2012-01-01

    .... However, on page 1066 of this issue, Glowacki et al. show that a strikingly different product distribution can be obtained in the oxidation of acetylene depending on whether the radicals contain high amounts of internal (vibrational...

  11. Theory of Arched Structures Strength, Stability, Vibration

    CERN Document Server

    Karnovsky, Igor A

    2012-01-01

    Theory of Arched Structures: Strength, Stability, Vibration presents detailed procedures for analytical analysis of the strength, stability, and vibration of arched structures of different types, using exact analytical methods of classical structural analysis. The material discussed is divided into four parts. Part I covers stress and strain with a particular emphasis on analysis; Part II discusses stability and gives an in-depth analysis of elastic stability of arches and the role that matrix methods play in the stability of the arches; Part III presents a comprehensive tutorial on dynamics and free vibration of arches, and forced vibration of arches; and Part IV offers a section on special topics which contains a unique discussion of plastic analysis of arches and the optimal design of arches.

  12. Piezoelectric energy harvesting from broadband random vibrations

    Science.gov (United States)

    Adhikari, S.; Friswell, M. I.; Inman, D. J.

    2009-11-01

    Energy harvesting for the purpose of powering low power electronic sensor systems has received explosive attention in the last few years. Most works using deterministic approaches focusing on using the piezoelectric effect to harvest ambient vibration energy have concentrated on cantilever beams at resonance using harmonic excitation. Here, using a stochastic approach, we focus on using a stack configuration and harvesting broadband vibration energy, a more practically available ambient source. It is assumed that the ambient base excitation is stationary Gaussian white noise, which has a constant power-spectral density across the frequency range considered. The mean power acquired from a piezoelectric vibration-based energy harvester subjected to random base excitation is derived using the theory of random vibrations. Two cases, namely the harvesting circuit with and without an inductor, have been considered. Exact closed-form expressions involving non-dimensional parameters of the electromechanical system have been given and illustrated using numerical examples.

  13. Vibrational and electronic spectroscopic studies of melatonin

    Science.gov (United States)

    Singh, Gurpreet; Abbas, J. M.; Dogra, Sukh Dev; Sachdeva, Ritika; Rai, Bimal; Tripathi, S. K.; Prakash, Satya; Sathe, Vasant; Saini, G. S. S.

    2014-01-01

    We report the infrared absorption and Raman spectra of melatonin recorded with 488 and 632.8 nm excitations in 3600-2700 and 1700-70 cm-1 regions. Further, we optimized molecular structure of the three conformers of melatonin within density functional theory calculations. Vibrational frequencies of all three conformers have also been calculated. Observed vibrational bands have been assigned to different vibrational motions of the molecules on the basis of potential energy distribution calculations and calculated vibrational frequencies. Observed band positions match well with the calculated values after scaling except Nsbnd H stretching mode frequencies. It is found that the observed and calculated frequencies mismatch of Nsbnd H stretching is due to intermolecular interactions between melatonin molecules.

  14. Vibration reduces thermal pain in adjacent dermatomes.

    Science.gov (United States)

    Yarnitsky, D; Kunin, M; Brik, R; Sprecher, E

    1997-01-01

    Spatial summation of thermal pain crosses dermatomal boundaries. In this study we examined whether a vibrational stimulus applied to adjacent or remote dermatomes affects thermal pain perception to the volar forearm. Contact heat at 2 degrees C above thermal pain threshold was applied, and a Visual Analog Scale (VAS) was used for pain assessment. We found a significant decrease in mean VAS rating when simultaneous vibratory stimuli were given to the dermatome adjacent to that receiving thermal stimulation, or to the same dermatome on the contralateral side. There was no change in VAS rating when vibration was given two or more dermatomes away. Vibration within the same dermatome also did not yield a significant change in VAS rating, possibly due to difficulty in magnitude assessment of stimuli given simultaneously within a single dermatome. The finding that vibration can reduce pain across dermatomes may allow for more flexible design of stimulation therapy for pain.

  15. Chronic subdural hematomas caused by vibrating Chinese ...

    African Journals Online (AJOL)

    Abstract. We present two middle aged Nigerian patients who developed significant chronic subdural hematomas weeks after going on vibrating Chinese massage chairs. This complication of using the chairs has not been previously reported.

  16. Rheumatic effects of vibration at work

    Science.gov (United States)

    Palmer, Keith T; Bovenzi, Massimo

    2016-01-01

    Occupational exposures to vibration come in many guises and are very common at a population level. It follows that an important minority of working-aged patients seen by medical services will have been exposed to this hazard of employment. Vibration can cause human health effects which may manifest in the patients that rheumatologists see. In this chapter we identify the health effects of relevance to them, and review their epidemiology, pathophysiology, clinical presentation, differential diagnosis, and vocational and clinical management. On either side of this, we describe the nature and assessment of the hazard, the scale and common patterns of exposure to vibration in the community, and the legal basis for controlling health risks, and comment on the role of health surveillance in detecting early adverse effects and what can be done to prevent the rheumatic effects of vibration at work. PMID:26612239

  17. Cable Vibration due to Ice Accretions

    DEFF Research Database (Denmark)

    Gjelstrup, Henrik; Georgakis, Christos; Larsen, Allan

    On March 29, 2001, the Great Belt East Bridge exhibited large-amplitude hanger vibrations having elliptical orbits for wind speeds of between 16 – 18m/s. Vibrational amplitudes were in the order of 2m in the across-wind direction and 0.6m in the along-wind. In this poster, a preliminary...... investigation behind the causes of this relatively isolated hanger vibration event on the Great Belt East Bridge is presented. Furthermore a stability criterion for a 3DOF bluff body is proposed. One of the main assumptions of the investigation is that icy conditions may have contributed in some way to large...... to a form of “drag instability”. From the visual observations of the vibrations it is assumed that the aerodynamic moment coefficient is zero...

  18. Vibrational and Rotational Energy Relaxation in Liquids

    DEFF Research Database (Denmark)

    Petersen, Jakob

    Vibrational and rotational energy relaxation in liquids are studied by means of computer simulations. As a precursor for studying vibrational energy relaxation of a solute molecule subsequent to the formation of a chemical bond, the validity of the classical Bersohn-Zewail model for describing......, the vibrational energy relaxation of I2 subsequent to photodissociation and recombination in CCl4 is studied using classical Molecular Dynamics simulations. The vibrational relaxation times and the time-dependent I-I pair distribution function are compared to new experimental results, and a qualitative agreement...... the intramolecular dynamics during photodissociation is investigated. The apparent agreement with quantum mechanical calculations is shown to be in contrast to the applicability of the individual approximations used in deriving the model from a quantum mechanical treatment. In the spirit of the Bersohn-Zewail model...

  19. International Conference on Acoustics and Vibration

    CERN Document Server

    Chaari, Fakher; Walha, Lasaad; Abdennadher, Moez; Abbes, Mohamed; Haddar, Mohamed

    2017-01-01

    The book provides readers with a snapshot of recent research and industrial trends in field of industrial acoustics and vibration. Each chapter, accepted after a rigorous peer-review process, reports on a selected, original piece of work presented and discussed at International Conference on Acoustics and Vibration (ICAV2016), which was organized by the Tunisian Association of Industrial Acoustics and Vibration (ATAVI) and held March 21-23, in Hammamet, Tunisia. The contributions, mainly written by north African authors, covers advances in both theory and practice in a variety of subfields, such as: smart materials and structures; fluid-structure interaction; structural acoustics as well as computational vibro-acoustics and numerical methods. Further topics include: engines control, noise identification, robust design, flow-induced vibration and many others.This book provides a valuable resource for both academics and professionals dealing with diverse issues in applied mechanics. By combining advanced theori...

  20. Ground vibrations emanating from construction equipment.

    Science.gov (United States)

    2012-09-01

    The recent trend in highway construction within New Hampshire has been toward reconstruction and rehabilitation projects in congested urban areas. This has resulted in a greater concern for vibrations generated by non-blasting construction activities...

  1. Tunable Mechanical Filter for Longitudinal Vibrations

    National Research Council Canada - National Science Library

    Asiri, S

    2007-01-01

    This paper presents both theoretically and experimentally a new kind of vibration isolator called tunable mechanical filter which consists of four parallel hybrid periodic rods connected between two plates...

  2. Vibration assisted femtosecond laser machining on metal

    Science.gov (United States)

    Park, Jung-Kyu; Yoon, Ji-Wook; Cho, Sung-Hak

    2012-06-01

    We demonstrate a novel approach to improve laser machining quality on metals by vibrating the optical objective lens with a frequency (of 500 Hz) and various displacements (0-16.5 μm) during a femtosecond laser machining process. The laser used in this experiment is an amplified Ti:sapphire fs laser system that generates 100 fs pulses having an energy of 3.5 mJ/pulse with a 5 kHz repetition rate at a central wavelength of 790 nm. It is found that both the wall surface finish of the machined structures and the aspect ratio obtained using the frequency vibration assisted laser machining are improved, compared to those derived via laser machining without vibration assistance. This is the first report of low frequency vibration of an optical objective lens in the femtosecond laser machining process being exploited to obtain significantly improved surface roughness of machined side walls and increased aspect ratios.

  3. Vibrations and stability of complex beam systems

    CERN Document Server

    Stojanović, Vladimir

    2015-01-01

     This book reports on solved problems concerning vibrations and stability of complex beam systems. The complexity of a system is considered from two points of view: the complexity originating from the nature of the structure, in the case of two or more elastically connected beams; and the complexity derived from the dynamic behavior of the system, in the case of a damaged single beam, resulting from the harm done to its simple structure. Furthermore, the book describes the analytical derivation of equations of two or more elastically connected beams, using four different theories (Euler, Rayleigh, Timoshenko and Reddy-Bickford). It also reports on a new, improved p-version of the finite element method for geometrically nonlinear vibrations. The new method provides more accurate approximations of solutions, while also allowing us to analyze geometrically nonlinear vibrations. The book describes the appearance of longitudinal vibrations of damaged clamped-clamped beams as a result of discontinuity (damage). It...

  4. Atomic packing and low energy vibrations in B2O3 glasses, compacted under GPa pressures

    Directory of Open Access Journals (Sweden)

    Giovanni Carini Jr.

    2017-06-01

    Full Text Available Vibrational properties of crystals are well described by Debye's theory. This doesn't hold for vitreous systems, where an excess density of low frequency vibrational states, called Boson peak, appears. In this work we study glassy boron trioxide (B2O3, a prototype system widely used as basic element of multi component glasses. Our aim is to get some insight into the dependence of mechanical and vibrational properties on the structure of glasses, i.e., on the atomic packing. For this reason, samples were compacted by using a multi anvil press up to pressures of 10 GPa. A comparative analysis of light Raman scattering and mechanical characteristics have been performed on densified samples. The results show that either Raman spectra and elastic constants are affected by the densification process owing to the hardening of the elastic continuum.

  5. Casing Vibration Fault Diagnosis Based on Variational Mode Decomposition, Local Linear Embedding, and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Yizhou Yang

    2017-01-01

    Full Text Available To diagnose mechanical faults of rotor-bearing-casing system by analyzing its casing vibration signal, this paper proposes a training procedure of a fault classifier based on variational mode decomposition (VMD, local linear embedding (LLE, and support vector machine (SVM. VMD is used first to decompose the casing signal into several modes, which are subsignals usually modulated by fault frequencies. Vibrational features are extracted from both VMD subsignals and the original one. LLE is employed here to reduce the dimensionality of these extracted features and make the samples more separable. Then low-dimensional data sets are used to train the multiclass SVM whose accuracy is tested by classifying the test samples. When the parameters of LLE and SVM are well optimized, this proposed method performs well on experimental data, showing its capacity of diagnosing casing vibration faults.

  6. Fatigue behavior of flexhoses and bellows due to flow-induced vibrations

    Science.gov (United States)

    Desai, P. V.; Thornhill, L.

    1986-01-01

    The analysis and results developed in a fresh approach to calculate flow induced vibration response of a flexible flow passage are summarized. The vibration results are further examined in the frequency domain to obtain dominant frequency information. A cumulative damage analysis due to cyclic strains is performed to obtain the number of cycles to failure for a metallic bellows of particular specifications under a variety of operational conditions. Sample plots of time and frequency domain responses are included. The complex listing of a computer program is provided. The program successively executes each of the analyses needed to calculate the vibration response, the frequency response, the cyclic strains and the number of cycles to failure. The program prompts the user for necessary input information. Sample data from the program is provided. The fatigue life results obtained by the computer model lie within an acceptable range of previously measured available data.

  7. Low-T magnetometry study of S = 1 Q2D [Ni(pyz)2(H2O)2](BF4)2 (pyz = pyrazine)

    Energy Technology Data Exchange (ETDEWEB)

    Manson, J. L. [Eastern Washington Univ., Cheney, WA (United States); Villa, D. Y. [Eastern Washington Univ., Cheney, WA (United States); Blackmore, W. J. A. [Univ. of Warwick, Coventry (United Kingdom); Brambleby, J. [Univ. of Warwick, Coventry (United Kingdom); Goddard, P. A. [Univ. of Warwick, Coventry (United Kingdom); Singleton, John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-13

    [Ni(pyz)2(H2O)2](BF4)2 (pyz = N2C4H4) was synthesized by a solvent-free technique and its structure solved by synchrotron X-ray powder diffraction.1 The compound contains S = 1 Ni(II) ions and has tetragonal symmetry. Two-D [Ni(pyz)2(H2O)2]2+ square lattices propagate in the ab-plane and stack along the c-axis (Fig. 1). Water ligands occupy axial sites and form H-bonds with interlayer BF4- ions. SQUID magnetometry shows a possible transition to long-range magnetic order near 3 K. We measured the magnetization of [Ni(pyz)2(H2O)2](BF4)2 as a function of temperature to search for field-induced phase transitions and briefly report those findings here.

  8. Vibration mode shape control by prestressing

    Science.gov (United States)

    Holnicki-Szulc, Jan; Haftka, Raphael T.

    1992-01-01

    A procedure is described for reducing vibration at sensitive locations on a structure, by induced distortions. The emphasis is placed on the excitation in a narrow frequency band, so that only a small number of vibration modes contribute to the intensity of the forced response. The procedure is demonstrated on an antenna truss example, showing that, with repeated frequencies, it is very easy to move nodal lines of one of the modes.

  9. Actual behaviour of a ball vibration absorber

    Czech Academy of Sciences Publication Activity Database

    Pirner, Miroš

    2002-01-01

    Roč. 90, č. 8 (2002), s. 987-1005 ISSN 0167-6105 R&D Projects: GA ČR(CZ) GV103/96/K034 Institutional support: RVO:68378297 Keywords : TV towers * wind-excited vibrations * vibration absorbers * pendulum absorber Subject RIV: JM - Building Engineering Impact factor: 0.513, year: 2002 http://www.sciencedirect.com/science/article/pii/S0167610502002155#

  10. Prediction of induced vibrations in stall

    Energy Technology Data Exchange (ETDEWEB)

    Thirstrup Petersen, J.; Thomsen, K.; Aagaard Madsen, H. [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

    1999-03-01

    The main results from recent research in stall induced vibrations are presented. The focus is on the edgewise blade vibrations, which during the last decade have turned out to be a potential threat against the stable operation of stall regulated wind turbines and a fact, which must be dealt with by the designer. The basic physical explanation for the phenomenon and examples of design precaution, which can be taken, are presented. (au)

  11. Human comfort in relation to sinusoidal vibration

    Science.gov (United States)

    Jones, B.; Rao, B. K. N.

    1975-01-01

    An investigation was made to assess the overall subjective comfort levels to sinusoidal excitations over the range 1 to 19 Hz using a two axis electrohydraulic vibration simulator. Exposure durations of 16 minutes, 25 minutes, 1 hour, and 2.5 hours have been considered. Subjects were not exposed over such durations, but were instructed to estimate the overall comfort levels preferred had they been constantly subjected to vibration over such durations.

  12. RESEARCH OF BRIDGE STRUCTURE VIBRATION CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    V.P. Babak

    2005-02-01

    Full Text Available  Bridge structure test results with using different types of dynamic force have been considered. It has been shown, that the developed technique of registering and processing vibration signals allows obtaining thin spectrum structure. The analysis of its change that is defined by the type of structure loading applied has been carried out. Key parameters of the vibration signals registered have been defined.

  13. Vibrations of Damaged Functionally Graded Cantilever Beams

    Science.gov (United States)

    Byrd, Larry W.; Birman, Victor

    2008-02-01

    The paper discusses closed-form solutions of the problems of free and forced vibrations of a functionally graded cantilever FGM beam with and without damage. The mode of damage considered in the paper is represented by cracks that are perpendicular to the axis of the beam. Notably, such mode of damage was observed in experiments on representative FGM beams. Forced vibrations considered in the paper were generated by a kinematic excitation of the clamped end of the beam.

  14. Vibration-Powered Radiation of Quaking Magnetar

    OpenAIRE

    Bastrukov, S.; Yu, J. W.; Xu, R. X.; Molodtsova, I.

    2011-01-01

    In juxtaposition with the standard model of rotation-powered pulsar, the model of vibration-powered magnetar undergoing quake-induced torsional Alfvén vibrations in its own ultrastrong magnetic field experiencing decay is considered. The presented line of argument suggests that the gradual decrease of frequencies (lengthening of periods) of long-periodic-pulsed radiation detected from a set of X-ray sources can be attributed to magnetic-field-decay-induced energy conversion from seismic vibra...

  15. Brain palpation from physiological vibrations using MRI

    OpenAIRE

    Zorgani, Ali; Souchon, Rémi; Dinh, Au-Hoang; Chapelon, Jean-Yves; Ménager, Jean-Michel; Lounis, Samir; Rouvière, Olivier; Catheline, Stefan

    2015-01-01

    It is commonly supposed that noise obscures but does not contain useful information. However, in wave physics and especially, seismology, scientists developed some tools known as “noise correlation” to extract useful information and construct images from the random vibrations of a medium. Living tissues are full of unexploited vibrations as well. In this manuscript, we show that noise correlation techniques in the brain using MRI can conduct to a tomography related to the stiffness that physi...

  16. Data Management Techniques for Blade Vibration Analysis

    Directory of Open Access Journals (Sweden)

    Przysowa Radosław

    2016-07-01

    Full Text Available Well-designed procedures are required to handle large amounts of data, generated by complex measurement systems used in engine tests. The paper presents selected methodologies and software tools for characterisation and monitoring of blade vibration. Common file formats and data structures as well as methods to process and visualise tip-timing data are discussed. Report Generation Framework (RGF developed in Python is demonstrated as a flexible tool for processing and publishing blade vibration results.

  17. Skyrmion Vibration Modes within the Rational Map Ansatz

    OpenAIRE

    Lin, W.T.; Piette, B.

    2008-01-01

    We study the vibration modes of the Skyrme model within the rational map ansatz. We show that the vibrations of the radial profiles and the rational maps are decoupled and we consider explicitly the cases B=1, B=2, and B=4. We then compare our results with the vibration modes obtained numerically by Barnes et al. and show that qualitatively the rational map reproduces the vibration modes obtained numerically but that the vibration frequencies of these modes do not match very well.

  18. Method and apparatus for vibrating a substrate during material formation

    Science.gov (United States)

    Bailey, Jeffrey A [Richland, WA; Roger, Johnson N [Richland, WA; John, Munley T [Benton City, WA; Walter, Park R [Benton City, WA

    2008-10-21

    A method and apparatus for affecting the properties of a material include vibrating the material during its formation (i.e., "surface sifting"). The method includes the steps of providing a material formation device and applying a plurality of vibrations to the material during formation, which vibrations are oscillations having dissimilar, non-harmonic frequencies and at least two different directions. The apparatus includes a plurality of vibration sources that impart vibrations to the material.

  19. Using piezo-electric material to simulate a vibration environment

    Science.gov (United States)

    Jepsen, Richard A.; Davie, Neil T.; Vangoethem, Douglas J.; Romero, Edward F.

    2010-12-14

    A target object can be vibrated using actuation that exploits the piezo-electric ("PE") property. Under combined conditions of vibration and centrifugal acceleration, a centrifugal load of the target object on PE vibration actuators can be reduced by using a counterweight that offsets the centrifugal loading. Target objects are also subjected to combinations of: spin, vibration, and acceleration; spin and vibration; and spin and acceleration.

  20. Reliability Analysis of Random Vibration Transmission Path Systems

    OpenAIRE

    Wei Zhao; Yi-Min Zhang

    2017-01-01

    The vibration transmission path systems are generally composed of the vibration source, the vibration transfer path, and the vibration receiving structure. The transfer path is the medium of the vibration transmission. Moreover, the randomness of transfer path influences the transfer reliability greatly. In this paper, based on the matrix calculus, the generalized second moment technique, and the stochastic finite element theory, the effective approach for the transfer reliability of vibratio...

  1. THE NEUROPHYSIOLOGICAL EFFECTS OF WHOLE BODY VIBRATION TRAINING

    OpenAIRE

    KOÇ, Gözde; K. Alparslan ERMAN

    2012-01-01

    Whole body vibration training, the person’s entire body on a platform, creates a vibration that may affect the muscles and bones. Despite the vibration used of massage and treatment since ancient times, it was used as a training method in recent years and became very popular and has attracted the attention of researchers. Whole body vibration training used both sport science with the aim to improve performance and in the fields of medicine for sports therapy. Whole body vibration training bri...

  2. Dancing drops over vibrating substrates

    Science.gov (United States)

    Borcia, Rodica; Borcia, Ion Dan; Helbig, Markus; Meier, Martin; Egbers, Christoph; Bestehorn, Michael

    2017-04-01

    We study the motion of a liquid drop on a solid plate simultaneously submitted to horizontal and vertical harmonic vibrations. The investigation is done via a phase field model earlier developed for describing static and dynamic contact angles. The density field is nearly constant in every bulk region (ρ = 1 in the liquid phase, ρ ≈ 0 in the vapor phase) and varies continuously from one phase to the other with a rapid but smooth variation across the interfaces. Complicated explicit boundary conditions along the interface are avoided and captured implicitly by gradient terms of ρ in the hydrodynamic basic equations. The contact angle θ is controlled through the density at the solid substrate ρ S , a free parameter varying between 0 and 1 [R. Borcia, I.D. Borcia, M. Bestehorn, Phys. Rev. E 78, 066307 (2008)]. We emphasize the swaying and the spreading modes, earlier theoretically identified by Benilov and Billingham via a shallow-water model for drops climbing uphill along an inclined plane oscillating vertically [E.S. Benilov, J. Billingham, J. Fluid Mech. 674, 93 (2011)]. The numerical phase field simulations will be completed by experiments. Some ways to prevent the release of the dancing drops along a hydrophobic surface into the gas atmosphere are also discussed in this paper.

  3. Vibrational characteristics of harp soundboards.

    Science.gov (United States)

    Waltham, Chris; Kotlicki, Andrzej

    2008-09-01

    Harps exist in different forms, from large factory-made concert harps to small hand-made folk harps. This variety presents both a challenge and an opportunity for acousticians. The musical quality of a harp depends on many factors, but key among these is the soundboard. This work sets out to define some general desirable qualities of a harp soundboard. First, in order to understand the relationship between the vibrational behavior of a bare soundboard and that of a completed instrument, a 36-string harp was built from scratch. Measurements were made at each stage of construction, and the results showed how the bare soundboard properties affect those of the finished harp. Second, the soundboards of several harps of different sizes were assessed by measuring the admittances along the string bar. These data showed that one relationship crucial to the quality of the soundboard is that between the modal shapes and modal frequencies of the soundboard, and the position and fundamental frequencies of the strings attached to it. A general statement is made about this relationship, one which should be of use to harp makers.

  4. Vibrational spectroscopic characterization of fluoroquinolones

    Science.gov (United States)

    Neugebauer, U.; Szeghalmi, A.; Schmitt, M.; Kiefer, W.; Popp, J.; Holzgrabe, U.

    2005-05-01

    Quinolones are important gyrase inhibitors. Even though they are used as active agents in many antibiotics, the detailed mechanism of action on a molecular level is so far not known. It is of greatest interest to shed light on this drug-target interaction to provide useful information in the fight against growing resistances and obtain new insights for the development of new powerful drugs. To reach this goal, on a first step it is essential to understand the structural characteristics of the drugs and the effects that are caused by the environment in detail. In this work we report on Raman spectroscopical investigations of a variety of gyrase inhibitors (nalidixic acid, oxolinic acid, cinoxacin, flumequine, norfloxacin, ciprofloxacin, lomefloxacin, ofloxacin, enoxacin, sarafloxacin and moxifloxacin) by means of micro-Raman spectroscopy excited with various excitation wavelengths, both in the off-resonance region (532, 633, 830 and 1064 nm) and in the resonance region (resonance Raman spectroscopy at 244, 257 and 275 nm). Furthermore DFT calculations were performed to assign the vibrational modes, as well as for an identification of intramolecular hydrogen bonding motifs. The effect of small changes in the drug environment was studied by adding successively small amounts of water until physiological low concentrations of the drugs in aqueous solution were obtained. At these low concentrations resonance Raman spectroscopy proved to be a useful and sensitive technique. Supplementary information was obtained from IR and UV/vis spectroscopy.

  5. Broadband Vibration Attenuation Using Hybrid Periodic Rods

    Directory of Open Access Journals (Sweden)

    S. Asiri

    2008-12-01

    Full Text Available This paper presents both theoretically and experimentally a new kind of a broadband vibration isolator. It is a table-like system formed by four parallel hybrid periodic rods connected between two plates. The rods consist of an assembly of periodic cells, each cell being composed of a short rod and piezoelectric inserts. By actively controlling the piezoelectric elements, it is shown that the periodic rods can efficiently attenuate the propagation of vibration from the upper plate to the lower one within critical frequency bands and consequently minimize the effects of transmission of undesirable vibration and sound radiation. In such a system, longitudinal waves can propagate from the vibration source in the upper plate to the lower one along the rods only within specific frequency bands called the "Pass Bands" and wave propagation is efficiently attenuated within other frequency bands called the "Stop Bands". The spectral width of these bands can be tuned according to the nature of the external excitation. The theory governing the operation of this class of vibration isolator is presented and their tunable filtering characteristics are demonstrated experimentally as functions of their design parameters. This concept can be employed in many applications to control the wave propagation and the force transmission of longitudinal vibrations both in the spectral and spatial domains in an attempt to stop/attenuate the propagation of undesirable disturbances.

  6. On Kinetics Modeling of Vibrational Energy Transfer

    Science.gov (United States)

    Gilmore, John O.; Sharma, Surendra P.; Cavolowsky, John A. (Technical Monitor)

    1996-01-01

    Two models of vibrational energy exchange are compared at equilibrium to the elementary vibrational exchange reaction for a binary mixture. The first model, non-linear in the species vibrational energies, was derived by Schwartz, Slawsky, and Herzfeld (SSH) by considering the detailed kinetics of vibrational energy levels. This model recovers the result demanded at equilibrium by the elementary reaction. The second model is more recent, and is gaining use in certain areas of computational fluid dynamics. This model, linear in the species vibrational energies, is shown not to recover the required equilibrium result. Further, this more recent model is inconsistent with its suggested rate constants in that those rate constants were inferred from measurements by using the SSH model to reduce the data. The non-linear versus linear nature of these two models can lead to significant differences in vibrational energy coupling. Use of the contemporary model may lead to significant misconceptions, especially when integrated in computer codes considering multiple energy coupling mechanisms.

  7. Droplet impact on vibrating superhydrophobic surfaces

    Science.gov (United States)

    Weisensee, Patricia B.; Ma, Jingcheng; Shin, Young Hwan; Tian, Junjiao; Chang, Yujin; King, William P.; Miljkovic, Nenad

    2017-10-01

    Many unanswered questions remain pertaining to droplet dynamics during impact on vibrating surfaces. Using optical high-speed imaging, we investigate the impact dynamics of macroscopic water droplets (≈2.5 mm ) on rigid and elastic superhydrophobic surfaces vibrating at 60-320 Hz and amplitudes of 0.2-2.7 mm. Specifically, we study the influence of the frequency, amplitude, rigidity, and substrate phase at the moment of impact on the contact time of impacting droplets. We show that a critical impact phase exists at which the contact time transitions from a minimum to a maximum greater than the theoretical contact time on a rigid, nonvibrating superhydrophobic surface. For impact at phases higher than the critical phase, contact times decrease until reaching a minimum of half the theoretical contact time just before the critical phase. The frequency of oscillation determines the phase-dependent variability of droplet contact times at different impact phases: higher frequencies (> 120 Hz) show less contact time variability and have overall shorter contact times compared to lower frequencies (60-120 Hz). The amplitude of vibration has little direct effect on the contact time. Through semiempirical modeling and comparison to experiments, we show that phase-averaged contact times can increase or decrease relative to a nonvibrating substrate for low (100 Hz ) vibration frequencies, respectively. This study not only provides new insights into droplet impact physics on vibrating surfaces, but also develops guidelines for the rational design of surfaces to achieve controllable droplet wetting in applications utilizing vibration.

  8. Behavior of Cell on Vibrating Micro Ridges

    Directory of Open Access Journals (Sweden)

    Haruka Hino

    2015-06-01

    Full Text Available The effect of micro ridges on cells cultured at a vibrating scaffold has been studied in vitro. Several parallel lines of micro ridges have been made on a disk of transparent polydimethylsiloxane for a scaffold. To apply the vibration on the cultured cells, a piezoelectric element was attached on the outside surface of the bottom of the scaffold. The piezoelectric element was vibrated by the sinusoidal alternating voltage (Vp-p < 16 V at 1.0 MHz generated by a function generator. Four kinds of cells were used in the test: L929 (fibroblast connective tissue of C3H mouse, Hepa1-6 (mouse hepatoma, C2C12 (mouse myoblast, 3T3-L1 (mouse fat precursor cells. The cells were seeded on the micro pattern at the density of 2000 cells/cm2 in the medium containing 10% FBS (fetal bovine serum and 1% penicillin/ streptomycin. After the adhesion of cells in several hours, the cells are exposed to the ultrasonic vibration for several hours. The cells were observed with a phase contrast microscope. The experimental results show that the cells adhere, deform and migrate on the scaffold with micro patterns regardless of the ultrasonic vibration. The effects of the vibration and the micro pattern depend on the kind of cells.

  9. No Telescoping Effect with Dual Tendon Vibration.

    Directory of Open Access Journals (Sweden)

    Valeria Bellan

    Full Text Available The tendon vibration illusion has been extensively used to manipulate the perceived position of one's own body part. However, findings from previous research do not seem conclusive sregarding the perceptual effect of the concurrent stimulation of both agonist and antagonist tendons over one joint. On the basis of recent data, it has been suggested that this paired stimulation generates an inconsistent signal about the limb position, which leads to a perceived shrinkage of the limb. However, this interesting effect has never been replicated. The aim of the present study was to clarify the effect of a simultaneous and equal vibration of the biceps and triceps tendons on the perceived location of the hand. Experiment 1 replicated and extended the previous findings. We compared a dual tendon stimulation condition with single tendon stimulation conditions and with a control condition (no vibration on both 'upward-downward' and 'towards-away from the elbow' planes. Our results show a mislocalisation towards the elbow of the position of the vibrated arm during dual vibration, in line with previous results; however, this did not clarify whether the effect was due to arm representation contraction (i.e., a 'telescoping' effect. Therefore, in Experiment 2 we investigated explicitly and implicitly the perceived arm length during the same conditions. Our results clearly suggest that in all the vibration conditions there was a mislocalisation of the entire arm (including the elbow, but no evidence of a contraction of the perceived arm length.

  10. Vibration Analysis of a Split Path Gearbox

    Science.gov (United States)

    Krantz, Timothy L.; Rashidi, Majid

    1995-01-01

    Split path gearboxes can be attractive alternatives to the common planetary designs for rotorcraft, but because they have seen little use, they are relatively high risk designs. To help reduce the risk of fielding a rotorcraft with a split path gearbox, the vibration and dynamic characteristics of such a gearbox were studied. A mathematical model was developed by using the Lagrangian method, and it was applied to study the effect of three design variables on the natural frequencies and vibration energy of the gearbox. The first design variable, shaft angle, had little influence on the natural frequencies. The second variable, mesh phasing, had a strong effect on the levels of vibration energy, with phase angles of 0 deg and 180 deg producing low vibration levels. The third design variable, the stiffness of the shafts connecting the spur gears to the helical pinions, strongly influenced the natural frequencies of some of the vibration modes, including two of the dominant modes. We found that, to achieve the lowest level of vibration energy, the natural frequencies of these two dominant modes should be less than those of the main excitation sources.

  11. Wavelet Correlation Feature Scale Entropy and Fuzzy Support Vector Machine Approach for Aeroengine Whole-Body Vibration Fault Diagnosis

    Directory of Open Access Journals (Sweden)

    Cheng-Wei Fei

    2013-01-01

    Full Text Available In order to correctly analyze aeroengine whole-body vibration signals, Wavelet Correlation Feature Scale Entropy (WCFSE and Fuzzy Support Vector Machine (FSVM (WCFSE-FSVM method was proposed by fusing the advantages of the WCFSE method and the FSVM method. The wavelet coefficients were known to be located in high Signal-to-Noise Ratio (S/N or SNR scales and were obtained by the Wavelet Transform Correlation Filter Method (WTCFM. This method was applied to address the whole-body vibration signals. The WCFSE method was derived from the integration of the information entropy theory and WTCFM, and was applied to extract the WCFSE values of the vibration signals. Among the WCFSE values, the WFSE1 and WCFSE2 values on the scale 1 and 2 from the high band of vibration signal were believed to acceptably reflect the vibration feature and were selected to construct the eigenvectors of vibration signals as fault samples to establish the WCFSE-FSVM model. This model was applied to aeroengine whole-body vibration fault diagnosis. Through the diagnoses of four vibration fault modes and the comparison of the analysis results by four methods (SVM, FSVM, WESE-SVM, WCFSE-FSVM, it is shown that the WCFSE-FSVM method is characterized by higher learning ability, higher generalization ability and higher anti-noise ability than other methods in aeroengine whole-vibration fault analysis. Meanwhile, this present study provides a useful insight for the vibration fault diagnosis of complex machinery besides an aeroengine.

  12. Simultaneous Measurement of Multiple Mechanical Properties of Single Cells Using AFM by Indentation and Vibration.

    Science.gov (United States)

    Zhang, Chuang; Shi, Jialin; Wang, Wenxue; Xi, Ning; Wang, Yuechao; Liu, Lianqing

    2017-12-01

    The mechanical properties of cells, which are the main characteristics determining their physical performance and physiological functions, have been actively studied in the fields of cytobiology and biomedical engineering and for the development of medicines. In this study, an indentation-vibration-based method is proposed to simultaneously measure the mechanical properties of cells in situ, including cellular mass (m), elasticity (k), and viscosity (c). The proposed measurement method is implemented based on the principle of forced vibration stimulated by simple harmonic force using an atomic force microscope (AFM) system integrated with a piezoelectric transducer as the substrate vibrator. The corresponding theoretical model containing the three mechanical properties is derived and used to perform simulations and calculations. Living and fixed human embryonic kidney 293 (HEK 293) cells were subjected to indentation and vibration to measure and compare their mechanical parameters and verify the proposed approach. The results that the fixed sample cells are more viscous and elastic than the living sample cells and the measured mechanical properties of cell are consistent within, but not outside of the central region of the cell, are in accordance with the previous studies. This work provides an approach to simultaneous measurement of the multiple mechanical properties of single cells using an integrated AFM system based on the principle force vibration and thickness-corrected Hertz model. This study should contribute to progress in biomedical engineering, cytobiology, medicine, early diagnosis, specific therapy and cell-powered robots.

  13. Monitoring Vibration of A Model of Rotating Machine

    Directory of Open Access Journals (Sweden)

    Arko Djajadi

    2012-03-01

    Full Text Available Mechanical movement or motion of a rotating machine normally causes additional vibration. A vibration sensing device must be added to constantly monitor vibration level of the system having a rotating machine, since the vibration frequency and amplitude cannot be measured quantitatively by only sight or touch. If the vibration signals from the machine have a lot of noise, there are possibilities that the rotating machine has defects that can lead to failure. In this experimental research project, a vibration structure is constructed in a scaled model to simulate vibration and to monitor system performance in term of vibration level in case of rotation with balanced and unbalanced condition. In this scaled model, the output signal of the vibration sensor is processed in a microcontroller and then transferred to a computer via a serial communication medium, and plotted on the screen with data plotter software developed using C language. The signal waveform of the vibration is displayed to allow further analysis of the vibration. Vibration level monitor can be set in the microcontroller to allow shutdown of the rotating machine in case of excessive vibration to protect the rotating machine from further damage. Experiment results show the agreement with theory that unbalance condition on a rotating machine can lead to larger vibration amplitude compared to balance condition. Adding and reducing the mass for balancing can be performed to obtain lower vibration level. 

  14. Powder Handling Device for X-ray Diffraction Analysis with Minimal Sample Preparation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project consists of developing a Vibrating Sample Holder (VSH) for planetary X-Ray Diffraction (XRD) instruments. The principle of this novel sample handling...

  15. Balanced sampling

    NARCIS (Netherlands)

    Brus, D.J.

    2015-01-01

    In balanced sampling a linear relation between the soil property of interest and one or more covariates with known means is exploited in selecting the sampling locations. Recent developments make this sampling design attractive for statistical soil surveys. This paper introduces balanced sampling

  16. Vibrational energy flow in substituted benzenes

    Science.gov (United States)

    Pein, Brandt C.

    Using ultrafast infrared (IR) Raman spectroscopy, vibrational energy flow was monitored in several liquid-state substituted benzenes at ambient temperature. In a series of mono-halogenated benzenes, X-C6H 5 (X = F, Cl, Br, I), a similar CH-stretch at 3068 cm-1 was excited using picosecond IR pulses and the resulting vibrational relaxation and overall vibrational cooling processes were monitored with anti-Stokes spectroscopy. In the molecules with a heavier halide substituent the CH-stretch decayed slower while midrange vibrations decayed faster. This result was logical if the density of states (DOS) in the first few tiers, which is the DOS composed of vibrations with smaller quantum number, is what primarily determines energy flow. For tiers 1-4, the DOS was nearly identical in the CH-stretch region while it increased in the midrange region for heavier halide mass. Excitation spectroscopy, an extension of 3D IR-Raman spectroscopy, was developed and used to selectively pump vibrations localized to the substituent or the phenyl group in nitrobenzene (NB), o-fluoronitrobenzene (OFNB) and o-nitrotoluene (ONT) and in the alkylbenzene series toluene, isopropylbenzene (IPB), and t-butylbenzene (TBB). Using quantum chemical calculations, each Raman active vibration was sorted, according to their atomic displacements, into three classifications: substituent, phenyl, or global. Using IR pump wavenumbers that initially excited substituent or phenyl vibrations, IR-Raman spectroscopy was used to monitor energy flowing from the substituent to phenyl vibrations and vice versa. In NB nitro-to-phenyl and nitro-to-global energy flow was almost nonexistent while phenyl-to-nitro and phenyl-to-global was weak. When ortho substituents (-CH3, -F) were introduced, energy flow from nitro-to-phenyl and nitro-to-global was activated. In ONT, phenyl-to-nitro energy flow ceased possibly due to the added methyl group diverting energy from entering the nitro vibrations. Energy flow is therefore

  17. Nanomechanical Infrared Spectroscopy with Vibrating Filters for Pharmaceutical Analysis

    DEFF Research Database (Denmark)

    Kurek, Maksymilian; Carnoy, Matthias; Larsen, Peter Emil

    2017-01-01

    Standard infrared spectroscopy techniques are well-developed and widely used. However, they typically require milligrams of sample and can involve time-consuming sample preparation. A promising alternative is represented by nanomechanical infrared spectroscopy (NAM-IR) based on the photothermal r...... perform a chemical and morphological analysis on roughly 100 pg of sample. With an absolute estimated sensitivity of 109±15 fg, the presented method is suitable for ultrasensitive vibrational spectroscopy....... response of a nanomechanical resonator, which enables the chemical analysis of picograms of analyte directly from a liquid solution in only a few minutes. Herein, we present NAM-IR using perforated membranes (filters). The method was tested with the pharmaceutical compound indomethacin to successfully...

  18. Experimental investigation of the effect of thermal hysteresis in MnFeP1-x Asx materials applied in an AMR device

    DEFF Research Database (Denmark)

    von Moos, Lars; Nielsen, Kaspar Kirstein; Engelbrecht, Kurt

    2012-01-01

    of this on magnetic refrigeration devices has not yet been thoroughly investigated in the literature. Here, the thermal hysteretic magnetocaloric properties are studied using vibrating sample magnetometry (VSM) and how this influences actual refrigeration performance, using an established active magnetic regenerator...

  19. Time-Resolved Magneto-Optical Imaging of Y1Ba2Cu3O7-delta Thin Films in High-Frequency AC Current Regime (Postprint)

    Science.gov (United States)

    2012-02-01

    Department of Defense, Washington Headquarters Services , Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite...film measured by the vibrating sample magnetometry ( VSM ) method [14]. The current density profiles change considerably with the phase. For example

  20. Some aspects of nanocrystalline nickel and zinc ferrites processed using microemulsion technique

    NARCIS (Netherlands)

    Misra, RDK; Kale, A; Kooi, BJ; De Hosson, JTM

    2003-01-01

    Nanocrystalline nickel and zinc ferrites synthesised using a microemulsion technique were characterised by high resolution transmission electron microscopy and vibrating sample magnetometry. A narrow and uniform distribution of crystals of size range 5-8 nm, distinguished by a clear lack of

  1. Self-propagating high temperature synthesis and magnetic ...

    Indian Academy of Sciences (India)

    Ni–Zn ferrite powders were synthesized by self-propagating high temperature synthesis (SHS) method. X-ray diffraction, TEM and vibrating sample magnetometry (VSM) were used to characterize the phase composition, microstructure and magnetic properties of the combustion products. The effect of the combustion ...

  2. Entropy for Mechanically Vibrating Systems

    Science.gov (United States)

    Tufano, Dante

    The research contained within this thesis deals with the subject of entropy as defined for and applied to mechanically vibrating systems. This work begins with an overview of entropy as it is understood in the fields of classical thermodynamics, information theory, statistical mechanics, and statistical vibroacoustics. Khinchin's definition of entropy, which is the primary definition used for the work contained in this thesis, is introduced in the context of vibroacoustic systems. The main goal of this research is to to establish a mathematical framework for the application of Khinchin's entropy in the field of statistical vibroacoustics by examining the entropy context of mechanically vibrating systems. The introduction of this thesis provides an overview of statistical energy analysis (SEA), a modeling approach to vibroacoustics that motivates this work on entropy. The objective of this thesis is given, and followed by a discussion of the intellectual merit of this work as well as a literature review of relevant material. Following the introduction, an entropy analysis of systems of coupled oscillators is performed utilizing Khinchin's definition of entropy. This analysis develops upon the mathematical theory relating to mixing entropy, which is generated by the coupling of vibroacoustic systems. The mixing entropy is shown to provide insight into the qualitative behavior of such systems. Additionally, it is shown that the entropy inequality property of Khinchin's entropy can be reduced to an equality using the mixing entropy concept. This equality can be interpreted as a facet of the second law of thermodynamics for vibroacoustic systems. Following this analysis, an investigation of continuous systems is performed using Khinchin's entropy. It is shown that entropy analyses using Khinchin's entropy are valid for continuous systems that can be decomposed into a finite number of modes. The results are shown to be analogous to those obtained for simple oscillators

  3. Vibrational energy relaxation in liquids

    Science.gov (United States)

    Chesnoy, J.; Gale, G. M.

    The de-excitation of the vibrational population of small molecules in the liquid state is considered. Experimental techniques applicable to the measurement of relaxation times in dense phases are first described. Theoretical approaches are subsequently developed with special emphasis on the relationship between ab-initio quantum methods and binary interaction models. Finally, a selection of experimental results is analysed in the light of these theories. Special attention is given to the dependence of the relaxation time on experimental parameters such as density, temperature or the concentration of a mixture. The behaviour of the relaxation time across the liquid/solid phase transition is also treated. La désexcitation vibrationnelle de petites molécules est étudiée en phase liquide. Les techniques expérimentales utilisables pour mesurer les temps de relaxation en phase dense sont d'abord décrites. Les approches théoriques sont ensuite développées en montrant en particulier les liens entre les deux principales : l'approche quantique ab-initio et les modèles d'interaction binaire. Un choix de résultats expérimentaux est finalement analysé à la lumière de ces théories. Les dépendances des temps de relaxation envers les paramètres expérimentaux, comme la densité, la température ou la concentration d'un mélange, sont spécialement étudiées. Le comportement de la relaxation à la transition liquide/solide est aussi abordé.

  4. Vibration transfers to measure the performance of vibration isolated platforms on site using background noise excitation

    NARCIS (Netherlands)

    Segerink, Franciscus B.; Korterik, Jeroen P.; Offerhaus, Herman L.

    2011-01-01

    This article demonstrates a quick and easy way of quantifying the performance of a vibration-isolated platform. We measure the vibration transfer from floor to table using background noise excitation from the floor. As no excitation device is needed, our setup only requires two identical sensors (in

  5. Vibrations and alternated stresses in turbomachineries; Vibrations et contraintes alternees dans les turbomachines

    Energy Technology Data Exchange (ETDEWEB)

    Naudin, M. [Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France)]|[FRAMATOME, 92 - Paris-La-Defense (France); Pugnet, J.M. [Conservatoire National des Arts et Metiers (CNAM), Grenoble-1 Univ., 38 (France)]|[FRAMATOME, 92 - Paris-La-Defense (France)

    1999-07-01

    Vibration phenomena are sources of mechanical incidents in turbomachineries. A calculation of the Eigenmodes of machine parts and a knowledge of their possible excitation during the machine operation can greatly improve the reliability and availability of the equipments. The development of computer tools and in particular the use of finite-element codes has allowed a more and more precise calculation of Eigenmodes and Eigenfrequencies. However, the analysis of excitation sources remains sometimes insufficient to explain and anticipate some complex vibrational phenomena encountered in rotative machines. The aim of this paper is to present, using two different examples, the methodology to be used in order to perform a complete vibrational analysis of mechanical components. The following aspects are reviewed successively: 1 - the damped vibrational system: study of the free motion, study of the response to an harmonic forced excitation; 2 - vibrational analysis of turbine blades: steam turbine blades, Eigenmodes of mobile blades, excitation sources, Campbell diagram, calculation of static and dynamical stresses, Haigh diagram, acceptance criteria and safety coefficient, influence of corrosion; 3 - dynamical analysis of the bending of a lineshaft: different flexion Eigenmodes, stiffness and damping of bearings, calculation of flexion Eigenmodes, excitation sources, vibrational stability of the lineshaft and vibration level; 3 - generalization: vibration of blades, shaft dynamics, alternative machines. (J.S.) 10 refs.

  6. Vibrational spectroscopy of Cm–C/Cb–Cb stretching vibrations of ...

    Indian Academy of Sciences (India)

    ... Pramana – Journal of Physics; Volume 74; Issue 1. Vibrational spectroscopy of –/ – stretching vibrations of copper tetramesityl porphyrin: An algebraic approach. Srinivasa Rao Karumuri Joydeep Choudhury Nirmal Kumar Sarkar Ramendu Bhattacharjee. Research Articles Volume 74 Issue 1 January 2010 pp ...

  7. Mars Science Laboratory Sample Acquisition, Sample Processing and Handling Subsystem: A Description of the Sampling Functionality

    Science.gov (United States)

    Jandura, L.; Burke, K.; Kennedy, B.; Melko, J.; Okon, A.; Sunshine, D.

    2009-12-01

    The Sample Acquisition/Sample Processing and Handling (SA/SPaH) subsystem for the Mars Science Library (MSL) is a rover-based sampling system scheduled to launch in 2011. The SA/SPaH consists of a powdering drill and a scooping, sieving, and portioning device mounted on a turret at the end of a robotic arm. Also on the turret is a dust removal tool for clearing the surface of scientific targets, and two science instruments mounted on vibration isolators. The SA/SPaH can acquire powder from rocks at depths of 20 to 50 mm and can also pick up loose regolith with its scoop. The acquired sample is sieved and portioned and delivered to one of two instruments inside the rover for analysis. The functionality of the system will be described along with the targets the system can acquire and the sample that can be delivered. Top View of the SA/SPaH on the Rover

  8. VLTI-UT vibrations effort and performances

    Science.gov (United States)

    Poupar, Sébastien; Haguenauer, Pierre; Alonso, Jaime; Schuhler, Nicolas; Henriquez, Juan-Pablo; Berger, Jean-Philippe; Bourget, Pierre; Brillant, Stephane; Castillo, Roberto; Gitton, Philippe; Gonte, Frederic; Di Lieto, Nicola; Lizon, Jean-Louis; Merand, Antoine; Woillez, Julien

    2014-07-01

    The ESO Very Large Telescope Interferometer (VLTI) using the Unit Telescope (UT) was strongly affected by vibrations since the first observations. Investigation by ESO on that subject had started in 2007, with a considerable effort since mid 2008. An important number of investigations on various sub-systems (On telescope: Guiding, Passive supports, Train Coude, insulation of electronics cabinets; On Instruments: dedicated campaign on each instruments with a special attention on the ones equipped with Close Cycle Cooler) were realized. Vibrations were not only recorded and analyzed using the usual accelerometers but also using on use sub-systems as InfRared Image Sensor (IRIS) and Multiple Applications Curvature Adaptive Optics (MACAO) and using a specific tool developed for vibrations measurements Mirror vibrAtion Metrology systeM for the Unit Telescope (MAMMUT). Those tools and systems have been used in order to improve the knowledge on telescope by finding sources. The sources whenever it was possible were damped. As known for years, instruments are still the principal sources of vibrations, for the majority of the UT. A special test in which 2 UTs instruments were completely shut down was realized to determine the minimum Optical Path Length (OPL) achievable. Vibrations is now a part of the instruments interface document and during the installation of any new instrument (KMOS) or system (AOF) a test campaign is realized. As a result some modifications (damping of CCC) can be asked in case of non-compliance. To ensure good operational conditions, levels of vibrations are regularly recorded to control any environmental change.

  9. Physiology responses of Rhesus monkeys to vibration

    Science.gov (United States)

    Hajebrahimi, Zahra; Ebrahimi, Mohammad; Alidoust, Leila; Arabian Hosseinabadi, Maedeh

    Vibration is one of the important environmental factors in space vehicles that it can induce severe physiological responses in most of the body systems such as cardiovascular, respiratory, skeletal, endocrine, and etc. This investigation was to assess the effect of different vibration frequencies on heart rate variability (HRV), electrocardiograms (ECG) and respiratory rate in Rhesus monkeys. Methods: two groups of rhesus monkey (n=16 in each group) was selected as control and intervention groups. Monkeys were held in a sitting position within a specific fixture. The animals of this experiment were vibrated on a table which oscillated right and left with sinusoidal motion. Frequency and acceleration for intervention group were between the range of 1 to 2000 Hz and +0.5 to +3 G during 36 weeks (one per week for 15 min), respectively. All of the animals passed the clinical evaluation (echocardiography, sonography, radiography and blood analysis test) before vibration test and were considered healthy and these tests repeated during and at the end of experiments. Results and discussions: Our results showed that heart and respiratory rates increased significantly in response to increased frequency from 1 to 60 Hz (p <0.05) directly with the +G level reaching a maximum (3G) within a seconds compare to controls. There were no significant differences in heart and respiratory rate from 60 t0 2000 Hz among studied groups. All monkeys passed vibration experiment successfully without any arrhythmic symptoms due to electrocardiography analysis. Conclusion: Our results indicate that vibration in low frequency can effect respiratory and cardiovascular function in rhesus monkey. Keywords: Vibration, rhesus monkey, heart rate, respiratory rate

  10. Epi-detection of vibrational phase contrast coherent anti-Stokes Raman scattering

    NARCIS (Netherlands)

    Garbacik, E.T.; Korterik, Jeroen P.; Otto, Cornelis; Herek, Jennifer Lynn; Offerhaus, Herman L.

    2014-01-01

    We demonstrate a system for the phase-resolved epi-detection of coherent anti-Stokes Raman scattering (CARS) signals in highly scattering and/or thick samples. With this setup, we measure the complex vibrational responses of multiple components in a thick, highly-scattering pharmaceutical tablet in

  11. Driving an Active Vibration Balancer to Minimize Vibrations at the Fundamental and Harmonic Frequencies

    Science.gov (United States)

    Holliday, Ezekiel S. (Inventor)

    2014-01-01

    Vibrations of a principal machine are reduced at the fundamental and harmonic frequencies by driving the drive motor of an active balancer with balancing signals at the fundamental and selected harmonics. Vibrations are sensed to provide a signal representing the mechanical vibrations. A balancing signal generator for the fundamental and for each selected harmonic processes the sensed vibration signal with adaptive filter algorithms of adaptive filters for each frequency to generate a balancing signal for each frequency. Reference inputs for each frequency are applied to the adaptive filter algorithms of each balancing signal generator at the frequency assigned to the generator. The harmonic balancing signals for all of the frequencies are summed and applied to drive the drive motor. The harmonic balancing signals drive the drive motor with a drive voltage component in opposition to the vibration at each frequency.

  12. Reliability Analysis of Random Vibration Transmission Path Systems

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    2017-01-01

    Full Text Available The vibration transmission path systems are generally composed of the vibration source, the vibration transfer path, and the vibration receiving structure. The transfer path is the medium of the vibration transmission. Moreover, the randomness of transfer path influences the transfer reliability greatly. In this paper, based on the matrix calculus, the generalized second moment technique, and the stochastic finite element theory, the effective approach for the transfer reliability of vibration transfer path systems was provided. The transfer reliability of vibration transfer path system with uncertain path parameters including path mass and path stiffness was analyzed theoretically and computed numerically, and the correlated mathematical expressions were derived. Thus, it provides the theoretical foundation for the dynamic design of vibration systems in practical project, so that most random path parameters can be considered to solve the random problems for vibration transfer path systems, which can avoid the system resonance failure.

  13. THE POTENTIAL NEURAL MECHANISMS OF ACUTE INDIRECT VIBRATION

    Directory of Open Access Journals (Sweden)

    Darryl J. Cochrane

    2011-03-01

    Full Text Available There is strong evidence to suggest that acute indirect vibration acts on muscle to enhance force, power, flexibility, balance and proprioception suggesting neural enhancement. Nevertheless, the neural mechanism(s of vibration and its potentiating effect have received little attention. One proposal suggests that spinal reflexes enhance muscle contraction through a reflex activity known as tonic vibration stretch reflex (TVR, which increases muscle activation. However, TVR is based on direct, brief, and high frequency vibration (>100 Hz which differs to indirect vibration, which is applied to the whole body or body parts at lower vibration frequency (5-45 Hz. Likewise, muscle tuning and neuromuscular aspects are other candidate mechanisms used to explain the vibration phenomenon. But there is much debate in terms of identifying which neural mechanism(s are responsible for acute vibration; due to a number of studies using various vibration testing protocols. These protocols include: different methods of application, vibration variables, training duration, exercise types and a range of population groups. Therefore, the neural mechanism of acute vibration remain equivocal, but spinal reflexes, muscle tuning and neuromuscular aspects are all viable factors that may contribute in different ways to increasing muscular performance. Additional research is encouraged to determine which neural mechanism(s and their contributions are responsible for acute vibration. Testing variables and vibration applications need to be standardised before reaching a consensus on which neural mechanism(s occur during and post-vibration

  14. Hydrogen local vibrational modes in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    McCluskey, Matthew D. [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-06-01

    Following, a review of experimental techniques, theory, and previous work, the results of local vibrational mode (LVM) spectroscopy on hydrogen-related complexes in several different semiconductors are discussed. Hydrogen is introduced either by annealing in a hydrogen ambient. exposure to a hydrogen plasma, or during growth. The hydrogen passivates donors and acceptors in semiconductors, forming neutral complexes. When deuterium is substituted for hydrogen. the frequency of the LVM decreases by approximately the square root of two. By varying the temperature and pressure of the samples, the microscopic structures of hydrogen-related complexes are determined. For group II acceptor-hydrogen complexes in GaAs, InP, and GaP, hydrogen binds to the host anion in a bond-centered orientation, along the [111] direction, adjacent to the acceptor. The temperature dependent shift of the LVMs are proportional to the lattice thermal energy U(T), a consequence of anharmonic coupling between the LVM and acoustical phonons. In the wide band gap semiconductor ZnSe, epilayers grown by metalorganic chemical vapor phase epitaxy (MOCVD) and doped with As form As-H complexes. The hydrogen assumes a bond-centered orientation, adjacent to a host Zn. In AlSb, the DX centers Se and Te are passivated by hydrogen. The second, third, and fourth harmonics of the wag modes are observed. Although the Se-D complex has only one stretch mode, the Se-H stretch mode splits into three peaks. The anomalous splitting is explained by a new interaction between the stretch LVM and multi-phonon modes of the lattice. As the temperature or pressure is varied, and anti-crossing is observed between LVM and phonon modes.

  15. Design of a nonlinear torsional vibration absorber

    Science.gov (United States)

    Tahir, Ammaar Bin

    Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is usually tuned for a specific resonant frequency or an operating frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies, or for a system with varying excitation frequency. Vibration dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. In this study, an experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber with geometrically induced cubic stiffness nonlinearity. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, the design optimization of the nonlinear torsional vibration absorber was carried out using an equivalent 2-DOF modal model. The optimality criterion was chosen to be maximization of energy dissipation in the nonlinear absorber attached to the equivalent 2-DOF system. The optimized design parameters of the nonlinear absorber were tested on the original 5-DOF system numerically. A comparison was made between the performance of linear and nonlinear absorbers using the numerical models. The comparison showed the superiority of the nonlinear absorber over its linear counterpart for the given set of primary system parameters as the vibration energy dissipation in the former is

  16. Vibrational lineshapes of adsorbates on solid surfaces

    Science.gov (United States)

    Ueba, H.

    A review is presented of the current activity in vibrational spectroscopy of adsorbates on metal surfaces. A brief introduction of the representative spectroscopies is given to demonstrate the rich information contained in vibrational spectra, which are characterized by their intensity, peak position and width. Analysis of vibrational spectra enables us to gain the deep insight into not only the local character of adsorption site or geometry, but also the dynamical interaction between the adsorbates or between the adsorbate and the substrate. Some recent instructive experimental results, mostly of a CO molecule adsorbed on various metal surfaces, are accompanied by the corresponding theoretical recipe for vibrational excitation mechanisms. Wide spread experimental results of the C-O stretching frequency of CO adsorbed on metal surfaces are discussed in terms of the chemical effect involving the static and dynamic charge transfers between the chemisorbed CO and metal, and also of the electrostatic dipole-dipole interaction between the molecules. The central subject of this review is directed to the linshapes characterized by the vibrational relaxation processes of adsorbates. A simple and transparent model is introduced to show that the characteristic decay time of the correlation function for the vibrational coordinates is the key quantity to determine the spectral lineshapes. Recent experimental results focused on a search for an intrinsic broadening mechanism are reviewed in the light of the so-called T1 (energy) and T2 (phase) relaxation processesof the vibrational excited states of adsorbates. Those are the vibrational energy dissipation into the elementary excitation, such as phonons or electron-hole pairs in the metal substrate, and pure dephasing due to the energy exchange with the sorroundings. The change of width and frequency by varying the experimental variables, such as temperature or isotope effect, provides indispensable knowledge for the dynamical

  17. Computation of expectation values from vibrational coupled-cluster at the two-mode coupling level

    DEFF Research Database (Denmark)

    Zoccante, Alberto; Seidler, Peter; Christiansen, Ove

    2011-01-01

    In this work we show how the vibrational coupled-cluster method at the two-mode coupling level can be used to calculate zero-point vibrational averages of properties. A technique is presented, where any expectation value can be calculated using a single set of Lagrangian multipliers computed...... solving iteratively a single linear set of equations. Sample calculations are presented which show that the resulting algorithm scales only with the third power of the number of modes, therefore making large systems accessible. Moreover, we present applications to water, pyrrole, and para-nitroaniline....

  18. Nanoscale piezoelectric vibration energy harvester design

    Science.gov (United States)

    Foruzande, Hamid Reza; Hajnayeb, Ali; Yaghootian, Amin

    2017-09-01

    Development of new nanoscale devices has increased the demand for new types of small-scale energy resources such as ambient vibrations energy harvesters. Among the vibration energy harvesters, piezoelectric energy harvesters (PEHs) can be easily miniaturized and fabricated in micro and nano scales. This change in the dimensions of a PEH leads to a change in its governing equations of motion, and consequently, the predicted harvested energy comparing to a macroscale PEH. In this research, effects of small scale dimensions on the nonlinear vibration and harvested voltage of a nanoscale PEH is studied. The PEH is modeled as a cantilever piezoelectric bimorph nanobeam with a tip mass, using the Euler-Bernoulli beam theory in conjunction with Hamilton's principle. A harmonic base excitation is applied as a model of the ambient vibrations. The nonlocal elasticity theory is used to consider the size effects in the developed model. The derived equations of motion are discretized using the assumed-modes method and solved using the method of multiple scales. Sensitivity analysis for the effect of different parameters of the system in addition to size effects is conducted. The results show the significance of nonlocal elasticity theory in the prediction of system dynamic nonlinear behavior. It is also observed that neglecting the size effects results in lower estimates of the PEH vibration amplitudes. The results pave the way for designing new nanoscale sensors in addition to PEHs.

  19. Vibration exposure and prevention in Japan.

    Science.gov (United States)

    Futatsuka, M; Ueno, T; Yamada, S

    1994-05-01

    Working conditions of vibration exposure have generally improved, but many difficult problems must be solved such as (1) hygienic improvements in a variety of vibrating tools; (2) improving working conditions, for example, by limiting the time of operation in spite of economic difficulties such as those faced by those who work on a piece rate basis; (3) gathering more complete information about the risk population because of the large number of self-employed in informal employment sectors; and (4) finding work places after rehabilitation for patients, particularly in mountainous rural areas or in small scale industries. Historical observation of vibration and preventive measures in Japanese national forests was presented on the basis of the results of a retrospective cohort study in Kyushu, Japan. Prevalence rate of VWF remarkably changed from 58.4% in the groups that began to operate chain saws in 1960 to only a few cases in the groups who started the operation after 1971. When we compare the relationships between the results of long term cohort study and the consequences of preventive measures of vibration syndrome, the most important factor is the decrease of vibration exposure (improvement in chain saws plus the time restriction system). The comprehensive prevention system used in Japanese national forests consists of the following: (1) Health care system; (2) Work regulation system; (3) System for improving mechanized tools; (4) Warming system to protect against cold conditions; and (5) Education and training system.

  20. Vibrational dephasing in matter-wave interferometers

    Science.gov (United States)

    Rembold, A.; Schütz, G.; Röpke, R.; Chang, W. T.; Hwang, I. S.; Günther, A.; Stibor, A.

    2017-03-01

    Matter-wave interferometry is a highly sensitive tool to measure small perturbations in a quantum system. This property allows the creation of precision sensors for dephasing mechanisms such as mechanical vibrations. They are a challenge for phase measurements under perturbing conditions that cannot be perfectly decoupled from the interferometer, e.g. for mobile interferometric devices or vibrations with a broad frequency range. Here, we demonstrate a method based on second-order correlation theory in combination with Fourier analysis, to use an electron interferometer as a sensor that precisely characterizes the mechanical vibration spectrum of the interferometer. Using the high spatial and temporal single-particle resolution of a delay line detector, the data allows to reveal the original contrast and spatial periodicity of the interference pattern from ‘washed-out’ matter-wave interferograms that have been vibrationally disturbed in the frequency region between 100 and 1000 Hz. Other than with electromagnetic dephasing, due to excitations of higher harmonics and additional frequencies induced from the environment, the parts in the setup oscillate with frequencies that can be different to the applied ones. The developed numerical search algorithm is capable to determine those unknown oscillations and corresponding amplitudes. The technique can identify vibrational dephasing and decrease damping and shielding requirements in electron, ion, neutron, atom and molecule interferometers that generate a spatial fringe pattern on the detector plane.

  1. Nanoscale piezoelectric vibration energy harvester design

    Directory of Open Access Journals (Sweden)

    Hamid Reza Foruzande

    2017-09-01

    Full Text Available Development of new nanoscale devices has increased the demand for new types of small-scale energy resources such as ambient vibrations energy harvesters. Among the vibration energy harvesters, piezoelectric energy harvesters (PEHs can be easily miniaturized and fabricated in micro and nano scales. This change in the dimensions of a PEH leads to a change in its governing equations of motion, and consequently, the predicted harvested energy comparing to a macroscale PEH. In this research, effects of small scale dimensions on the nonlinear vibration and harvested voltage of a nanoscale PEH is studied. The PEH is modeled as a cantilever piezoelectric bimorph nanobeam with a tip mass, using the Euler-Bernoulli beam theory in conjunction with Hamilton’s principle. A harmonic base excitation is applied as a model of the ambient vibrations. The nonlocal elasticity theory is used to consider the size effects in the developed model. The derived equations of motion are discretized using the assumed-modes method and solved using the method of multiple scales. Sensitivity analysis for the effect of different parameters of the system in addition to size effects is conducted. The results show the significance of nonlocal elasticity theory in the prediction of system dynamic nonlinear behavior. It is also observed that neglecting the size effects results in lower estimates of the PEH vibration amplitudes. The results pave the way for designing new nanoscale sensors in addition to PEHs.

  2. A hybrid nonlinear vibration energy harvester

    Science.gov (United States)

    Yang, Wei; Towfighian, Shahrzad

    2017-06-01

    Vibration energy harvesting converts mechanical energy from ambient sources to electricity to power remote sensors. Compared to linear resonators that have poor performance away from their natural frequency, nonlinear vibration energy harvesters perform better because they use vibration energy over a broader spectrum. We present a hybrid nonlinear energy harvester that combines bi-stability with internal resonance to increase the frequency bandwidth. A two-fold increase in the frequency bandwidth can be obtained compared to a bi-stable system with fixed magnets. The harvester consists of a piezoelectric cantilever beam carrying a movable magnet facing a fixed magnet. A spring allows the magnet to move along the beam and it provides an extra stored energy to further increase the amplitude of vibration acting as a mechanical amplifier. An electromechanically coupled mathematical model of the system is presented to obtain the dynamic response of the cantilever beam, the movable magnet and the output voltage. The perturbation method of multiple scales is applied to solve these equations and obtain approximate analytical solutions. The effects of various system parameters on the frequency responses are investigated. The numerical approaches of the long time integration (Runge-Kutta method) and the shooting technique are used to verify the analytical results. The results of this study can be used to improve efficiency in converting wasted mechanical vibration to useful electrical energy by broadening the frequency bandwidth.

  3. Active vibration control using DEAP actuators

    Science.gov (United States)

    Sarban, Rahimullah; Jones, Richard W.

    2010-04-01

    Dielectric electro-active polymer (DEAP) is a new type of smart material, which has the potential to be used to provide effective actuation for a wide range of applications. The properties of DEAP material place it somewhere between those of piezoceramics and shape memory alloys. Of the range of DEAP-based actuators that have been developed those having a cylindrical configuration are among the most promising. This contribution introduces the use of a tubular type DEAP actuator for active vibration control purposes. Initially the DEAP-based tubular actuator to be used in this study, produced by Danfoss PolyPower A/S, is introduced along with the static and dynamic characteristics. Secondly an electromechanical model of the tubular actuator is briefly reviewed and its ability to model the actuator's hysteresis characteristics for a range of periodic input signals at different frequencies demonstrated. The model will be used to provide hysteresis compensation in future vibration isolation studies. Experimental active vibration control using the actuator is then examined, specifically active vibration isolation of a 250 g mass subject to shaker generated 'ground vibration'. An adaptive feedforward control strategy is used to achieve this. The ability of the tubular actuator to reject both tonal and broadband random vibratory disturbances is then demonstrated.

  4. Vibration Isolation for Parallel Hydraulic Hybrid Vehicles

    Directory of Open Access Journals (Sweden)

    The M. Nguyen

    2008-01-01

    Full Text Available In recent decades, several types of hybrid vehicles have been developed in order to improve the fuel economy and to reduce the pollution. Hybrid electric vehicles (HEV have shown a significant improvement in fuel efficiency for small and medium-sized passenger vehicles and SUVs. HEV has several limitations when applied to heavy vehicles; one is that larger vehicles demand more power, which requires significantly larger battery capacities. As an alternative solution, hydraulic hybrid technology has been found effective for heavy duty vehicle because of its high power density. The mechanical batteries used in hydraulic hybrid vehicles (HHV can be charged and discharged remarkably faster than chemical batteries. This feature is essential for heavy vehicle hybridization. One of the main problems that should be solved for the successful commercialization of HHV is the excessive noise and vibration involving with the hydraulic systems. This study focuses on using magnetorheological (MR technology to reduce the noise and vibration transmissibility from the hydraulic system to the vehicle body. In order to study the noise and vibration of HHV, a hydraulic hybrid subsystem in parallel design is analyzed. This research shows that the MR elements play an important role in reducing the transmitted noise and vibration to the vehicle body. Additionally, locations and orientations of the isolation system also affect the efficiency of the noise and vibration mitigation. In simulations, a skyhook control algorithm is used to achieve the highest possible effectiveness of the MR isolation system.

  5. Whole-Body Vibration and Blood Flow and Muscle Oxygenation: A Meta-Analysis

    Science.gov (United States)

    Games, Kenneth E.; Sefton, JoEllen M.; Wilson, Alan E.

    2015-01-01

    Context: The use and popularity of whole-body vibration (WBV) has increased in recent years, but there is a lack of consensus in the literature about the effectiveness of the treatment. Objective: To quantitatively examine the effects of WBV on muscle oxygenation and peripheral blood flow in healthy adults. Data Sources: We searched Web of Science and PubMed databases and reference lists from relevant articles using the key terms whole body vibration, whole-body vibration, WBV, blood flow, peripheral blood flow, oxygenation, muscle oxygenation, circulation, circulatory, near infrared spectroscopy, NIRS, and power Doppler. Key terms were searched using single word and combination searches. No date range was specified. Study Selection: Criteria for inclusion were (1) use of a commercially available WBV device, (2) a human research model, (3) a pre-WBV condition and at least 1 WBV experimental condition, and (4) reporting of unstandardized means and standard deviations of muscle oxygenation or peripheral blood flow. Data Extraction: Means, standard deviations, and sample sizes were extracted from the text, tables, and figures of included studies. A total of 35 and 90 data points were extracted for the muscle-oxygenation and blood-flow meta-analyses, respectively. Data for each meta-analysis were combined and analyzed using meta-analysis software. Weighted, random-effects meta-analyses using the Hedges g metric were completed for muscle oxygenation and blood flow. We then conducted follow-up analyses using the moderator variables of vibration type, vibration time, vibration frequency, measurement location, and sample type. Data Synthesis: We found 18 potential articles. Further examination yielded 10 studies meeting the inclusion criteria. Whole-body vibration was shown to positively influence peripheral blood flow. Additionally, the moderators of vibration type and frequency altered the influence of WBV on blood flow. Overall, WBV did not alter muscle oxygenation

  6. Whole-body vibration and blood flow and muscle oxygenation: a meta-analysis.

    Science.gov (United States)

    Games, Kenneth E; Sefton, JoEllen M; Wilson, Alan E

    2015-05-01

    The use and popularity of whole-body vibration (WBV) has increased in recent years, but there is a lack of consensus in the literature about the effectiveness of the treatment. To quantitatively examine the effects of WBV on muscle oxygenation and peripheral blood flow in healthy adults. We searched Web of Science and PubMed databases and reference lists from relevant articles using the key terms whole body vibration, whole-body vibration, WBV, blood flow, peripheral blood flow, oxygenation, muscle oxygenation, circulation, circulatory, near infrared spectroscopy, NIRS, and power Doppler. Key terms were searched using single word and combination searches. No date range was specified. Criteria for inclusion were (1) use of a commercially available WBV device, (2) a human research model, (3) a pre-WBV condition and at least 1 WBV experimental condition, and (4) reporting of unstandardized means and standard deviations of muscle oxygenation or peripheral blood flow. Means, standard deviations, and sample sizes were extracted from the text, tables, and figures of included studies. A total of 35 and 90 data points were extracted for the muscle-oxygenation and blood-flow meta-analyses, respectively. Data for each meta-analysis were combined and analyzed using meta-analysis software. Weighted, random-effects meta-analyses using the Hedges g metric were completed for muscle oxygenation and blood flow. We then conducted follow-up analyses using the moderator variables of vibration type, vibration time, vibration frequency, measurement location, and sample type. We found 18 potential articles. Further examination yielded 10 studies meeting the inclusion criteria. Whole-body vibration was shown to positively influence peripheral blood flow. Additionally, the moderators of vibration type and frequency altered the influence of WBV on blood flow. Overall, WBV did not alter muscle oxygenation; however, when the measurement site was considered, muscle oxygenation increased or

  7. Magneto-Structural Correlations in Pseudotetrahedral Forms of the [Co(SPh)4]2- Complex Probed by Magnetometry, MCD Spectroscopy, Advanced EPR Techniques, and ab Initio Electronic Structure Calculations.

    Science.gov (United States)

    Suturina, Elizaveta A; Nehrkorn, Joscha; Zadrozny, Joseph M; Liu, Junjie; Atanasov, Mihail; Weyhermüller, Thomas; Maganas, Dimitrios; Hill, Stephen; Schnegg, Alexander; Bill, Eckhard; Long, Jeffrey R; Neese, Frank

    2017-03-06

    The magnetic properties of pseudotetrahedral Co(II) complexes spawned intense interest after (PPh4)2[Co(SPh)4] was shown to be the first mononuclear transition-metal complex displaying slow relaxation of the magnetization in the absence of a direct current magnetic field. However, there are differing reports on its fundamental magnetic spin Hamiltonian (SH) parameters, which arise from inherent experimental challenges in detecting large zero-field splittings. There are also remarkable changes in the SH parameters of [Co(SPh)4]2- upon structural variations, depending on the counterion and crystallization conditions. In this work, four complementary experimental techniques are utilized to unambiguously determine the SH parameters for two different salts of [Co(SPh)4]2-: (PPh4)2[Co(SPh)4] (1) and (NEt4)2[Co(SPh)4] (2). The characterization methods employed include multifield SQUID magnetometry, high-field/high-frequency electron paramagnetic resonance (HF-EPR), variable-field variable-temperature magnetic circular dichroism (VTVH-MCD), and frequency domain Fourier transform THz-EPR (FD-FT THz-EPR). Notably, the paramagnetic Co(II) complex [Co(SPh)4]2- shows strong axial magnetic anisotropy in 1, with D = -55(1) cm-1 and E/D = 0.00(3), but rhombic anisotropy is seen for 2, with D = +11(1) cm-1 and E/D = 0.18(3). Multireference ab initio CASSCF/NEVPT2 calculations enable interpretation of the remarkable variation of D and its dependence on the electronic structure and geometry.

  8. The structure of filled skutterudites and the local vibration behavior of the filling atom

    Science.gov (United States)

    Zhou, Xiaojuan; Zong, Peng-an; Chen, Xihong; Tao, Juzhou; Lin, He

    2017-02-01

    Both of atomic pair distribution function (PDF) and extended x-ray absorption fine structure (EXAFS) experiments have been carried out on unfilled and Yb-filled skutterudites YbxCo4Sb12 (x=0, 0.15, 0.2 and 0.25) samples. The structure refinements on PDF data confirm the large amplitude vibration of Yb atom and the dependence of Yb vibration amplitude on the filling content. Temperature dependent EXAFS experiment on filled skutterudites have been carried out at Yb LⅢ-edge in order to explore the local vibration behavior of filled atom. EXAFS experiments show that the Einstein temperature of the filled atom is very low (70.9 K) which agrees with the rattling behavior.

  9. Semi-Active Pulse-Switching Vibration Suppression Using Sliding Time Window

    Directory of Open Access Journals (Sweden)

    S. Mohammadi

    2013-01-01

    Full Text Available The performance of pulse-switching vibration control technique is investigated using a new method for switching sequence, in order to enhance the vibration damping. The control law in this method which was developed in the field of piezoelectric damping is based on triggering the inverting switch on each extremum of the produced voltage (or displacement; however, its efficiency in the case of random excitation is arguable because of the local extremum detection process. The new proposed method for switching sequence is only based on the fact that the triggering voltage level was determined using windowed statistical examination of the deflection signal. Results for a cantilever beam excited by different excitation forces, such as stationary and nonstationary random samples, and pulse forces are presented. A significant decrease in vibration energy and also the robustness of this method are demonstrated.

  10. The structure of filled skutterudites and the local vibration behavior of the filling atom

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiaojuan [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Dongguan Institute of Neutron Science, Dongguan 523808 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zong, Peng-an [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Chen, Xihong [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Tao, Juzhou, E-mail: taoj@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Dongguan Institute of Neutron Science, Dongguan 523808 (China); Lin, He, E-mail: linhe@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai 201204 (China)

    2017-02-15

    Both of atomic pair distribution function (PDF) and extended x-ray absorption fine structure (EXAFS) experiments have been carried out on unfilled and Yb-filled skutterudites Yb{sub x}Co{sub 4}Sb{sub 12} (x=0, 0.15, 0.2 and 0.25) samples. The structure refinements on PDF data confirm the large amplitude vibration of Yb atom and the dependence of Yb vibration amplitude on the filling content. Temperature dependent EXAFS experiment on filled skutterudites have been carried out at Yb L{sub Ⅲ}-edge in order to explore the local vibration behavior of filled atom. EXAFS experiments show that the Einstein temperature of the filled atom is very low (70.9 K) which agrees with the rattling behavior.

  11. A method of real-time fault diagnosis for power transformers based on vibration analysis

    Science.gov (United States)

    Hong, Kaixing; Huang, Hai; Zhou, Jianping; Shen, Yimin; Li, Yujie

    2015-11-01

    In this paper, a novel probability-based classification model is proposed for real-time fault detection of power transformers. First, the transformer vibration principle is introduced, and two effective feature extraction techniques are presented. Next, the details of the classification model based on support vector machine (SVM) are shown. The model also includes a binary decision tree (BDT) which divides transformers into different classes according to health state. The trained model produces posterior probabilities of membership to each predefined class for a tested vibration sample. During the experiments, the vibrations of transformers under different conditions are acquired, and the corresponding feature vectors are used to train the SVM classifiers. The effectiveness of this model is illustrated experimentally on typical in-service transformers. The consistency between the results of the proposed model and the actual condition of the test transformers indicates that the model can be used as a reliable method for transformer fault detection.

  12. A Method to Assess Transverse Vibration Energy of Ship Propeller Shaft for Diagnostic Purposes

    Directory of Open Access Journals (Sweden)

    Korczewski Zbigniew

    2017-12-01

    Full Text Available The article discusses a key problem of ship propulsion system vibration diagnostics, which concerns assessing this part of mechanical energy transmitted from the main engine to the ship propeller which is dissipated due to propeller shaft vibration. A simplified calculation model is proposed which allows the total energy of the generated torsional vibration to be assessed from the shaft deflection amplitude measured at the mind-span point between the supports. To verify the developed model, pilot tests were performed on the laboratory rotational mechanical system test rig. In those tests, cyclic bending moment was applied to a unified (cylindrical material sample, which modelled, at an appropriate scale, structural and functional properties of a real propeller shaft.

  13. Vibrational Spectra and Heat Capacity of Methane, and the Speed of Sound

    Science.gov (United States)

    Tennis, Ronald; Bailey, Ryan; Henderson, Giles

    2000-12-01

    A two-part physical chemistry laboratory experiment is described in which students evaluate statistical mechanical theory by comparing a measured speed of sound and heat capacity with values predicted from vibrational spectra. In part 1 students measure the IR spectrum of CH4(g) and the Raman spectrum of CH4(l) to determine quantized vibrational energy spacings. Strong Raman scattering of a pulsed nitrogen laser beam is observed with a liquid methane sample in a custom cryogenic cell constructed from two side-arm test tubes and a length of Pyrex tube. These data are used with the statistical mechanics of a harmonic oscillator to calculate vibrational heat capacities and CP/CV; of CH4(g) and the speed of sound in CH4(g). In part 2, the predicted speed of sound is compared with an experimental value measured with a simple acoustic resonance cavity (Kundt's tube) exhausted to a Bunsen burner.

  14. Concorde noise-induced building vibrations for Sully Plantation, Chantilly, Virginia

    Science.gov (United States)

    Mayes, W. H.; Scholl, H. F.; Stephens, D. G.; Holliday, B. G.; Deloach, R.; Holmes, H. K.; Lewis, R. B.; Lynch, J. W.

    1976-01-01

    A study to assess the noise-induced building vibrations associated with Concorde operations is presented. The approach is to record the levels of induced vibrations and associated indoor/outdoor noise levels in selected homes, historic and other buildings near Dulles and Kennedy International Airports. Presented is a small, representative sample of data recorded at Sully Plantation, Chantilly, Virginia during the period of May 20 through May 28, 1976. Recorded data provide relationships between the vibration levels of walls, floors, windows, and the noise associated with Concorde operations (2 landings and 3 takeoffs), other aircraft, nonaircraft sources, and normal household activities. Results suggest that building vibrations resulting from aircraft operations were proportional to the overall sound pressure levels and relatively insensitive to spectral differences associated with the different types of aircraft. Furthermore, the maximum levels of vibratory response resulting from Concorde operations were higher than those associated with conventional aircraft. The vibrations of nonaircraft events were observed in some cases to exceed the levels resulting from aircraft operations. These nonaircraft events are currently being analyzed in greater detail.

  15. Effects of whole-body vibration training on fibrinolytic and coagulative factors in healthy young men

    Directory of Open Access Journals (Sweden)

    Farshad Ghazalian

    2014-01-01

    Full Text Available Background: The aim was to evaluate effects of 5-week whole body vibration (WBV training with different amplitudes and progressive frequencies on fibrinolytic/coagulative factors. Materials and Methods: 25 subjects were divided randomly in high or low-amplitude vibration, and control groups. Training consisted of 5-week WBV with amplitudes 4 or 2 mm. Plasma samples were analyzed before and after training. Statistical analysis was done using one-way analysis of variance and Wilcoxon signed ranked test. P <0.05 was considered significant. Results: High-amplitude vibration caused an increase in tissue plasminogen activator (tPA (P = 0.028 (pretest: 1744.61 ± 707.95; posttest: 2313.63 ± 997.19 pg/ml, and decrease in plasminogen activator inhibitor-1 (PAI-1 (P = 0.033 (pretest: 97.94 ± 34.37; posttest: 85.12 ± 36.92 ng/ml. Fibrinogen and plasminogen were not changed significantly. Low-amplitude vibration caused an increase in tPA (P = 0.006 (pretest: 2208.18 ± 1280.37; posttest: 3492.72 ± 3549.22 pg/ml. PAI-1, fibrinogen and plasminogen were not changed significantly. There were no significant differences between groups. Conclusion: Amplitude of vibrations in WBV training may affect fibrinolytic factors.

  16. Desert ants learn vibration and magnetic landmarks.

    Directory of Open Access Journals (Sweden)

    Cornelia Buehlmann

    Full Text Available The desert ants Cataglyphis navigate not only by path integration but also by using visual and olfactory landmarks to pinpoint the nest entrance. Here we show that Cataglyphis noda can additionally use magnetic and vibrational landmarks as nest-defining cues. The magnetic field may typically provide directional rather than positional information, and vibrational signals so far have been shown to be involved in social behavior. Thus it remains questionable if magnetic and vibration landmarks are usually provided by the ants' habitat as nest-defining cues. However, our results point to the flexibility of the ants' navigational system, which even makes use of cues that are probably most often sensed in a different context.

  17. Collective model for isovector quadrupole vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Nojarov, R.; Faessler, A.

    1987-03-01

    The vibrational model is extended by introducing isospin-dependent collective coordinates, permitting a description out-of-phase neutron-proton vibrations coupled by a density-dependent symmetry energy. The restoring force is calculated microscopically using the wavefunctions of a Woods-Saxon potential and the coupling with three-phonon states is taken into account. The model is able to describe the available experimental data (energies and multipole mixing ratios) on low-lying 2/sup +/ states, which were observed recently in nuclei near the shell closures (/sup 124/Te, /sup 140/Ba, /sup 142/Ce and /sup 144/Nd), supporting the identification of these states as isovector quadrupole vibrations and predicting such states in /sup 126 -130/ Te.

  18. Wind Turbine Rotors with Active Vibration Control

    DEFF Research Database (Denmark)

    Svendsen, Martin Nymann

    This thesis presents a framework for structural modeling, analysis and active vibration damping of rotating wind turbine blades and rotors. A structural rotor model is developed in terms of finite beam elements in a rotating frame of reference. The element comprises a representation of general...... formulation. The element provides an accurate representation of the eigenfrequencies and whirling modes of the gyroscopic system, and identifies lightly damped edge-wise modes. By adoption of a method for active, collocated resonant vibration of multi-degree-of-freedom systems it is demonstrated...... that these are geometrically well separated. For active vibration control in three-bladed wind turbine rotors the present work presents a resonance-based method for groups of one collective and two whirling modes. The controller is based on the existing resonant format and introduces a dual system targeting the collective...

  19. Mechanical vibration to electrical energy converter

    Science.gov (United States)

    Kellogg, Rick Allen [Tijeras, NM; Brotz, Jay Kristoffer [Albuquerque, NM

    2009-03-03

    Electromechanical devices that generate an electrical signal in response to an external source of mechanical vibrations can operate as a sensor of vibrations and as an energy harvester for converting mechanical vibration to electrical energy. The devices incorporate a magnet that is movable through a gap in a ferromagnetic circuit, wherein a coil is wound around a portion of the ferromagnetic circuit. A flexible coupling is used to attach the magnet to a frame for providing alignment of the magnet as it moves or oscillates through the gap in the ferromagnetic circuit. The motion of the magnet can be constrained to occur within a substantially linear range of magnetostatic force that develops due to the motion of the magnet. The devices can have ferromagnetic circuits with multiple arms, an array of magnets having alternating polarity and, encompass micro-electromechanical (MEM) devices.

  20. Conformational and vibrational reassessment of solid paracetamol

    Science.gov (United States)

    Amado, Ana M.; Azevedo, Celeste; Ribeiro-Claro, Paulo J. A.

    2017-08-01

    This work provides an answer to the urge for a more detailed and accurate knowledge of the vibrational spectrum of the widely used analgesic/antipyretic drug commonly known as paracetamol. A comprehensive spectroscopic analysis - including infrared, Raman, and inelastic neutron scattering (INS) - is combined with a computational approach which takes account for the effects of intermolecular interactions in the solid state. This allows a full reassessment of the vibrational assignments for Paracetamol, thus preventing the propagation of incorrect data analysis and misassignments already found in the literature. In particular, the vibrational modes involving the hydrogen-bonded Nsbnd H and Osbnd H groups are correctly reallocated to bands shifted by up to 300 cm- 1 relatively to previous assignments.

  1. Effects of Cutting Tool Parameters on Vibration

    Directory of Open Access Journals (Sweden)

    Ince Mehmet Alper

    2016-01-01

    Full Text Available This paper presents of the influence on vibration of Co28Cr6Mo medical alloy machined on a CNC lathe based on cutting parameters (rotational speed, feed rate, depth of cut and tool tip radius. The influences of cutting parameters have been presented in graphical form for understanding. To achieve the minimum vibration, the optimum values obtained for rpm, feed rate, depth of cut and tool tip radius were respectively, 318 rpm, 0.25 mm/rev, 0.9 mm and 0.8 mm. Maximum vibration has been revealed the values obtained for rpm, feed rate, depth of cut and tool tip radius were respectively, 636 rpm, 0.1 mm/rev, 0,5 mm and 0.8 mm.

  2. Chatter vibrations of high-performance motorcycles

    Science.gov (United States)

    Sharp, R. S.; Watanabe, Y.

    2013-03-01

    Motorcycle racing teams occasionally experience speed-limiting vibrations of around 25 Hz frequency in mid-corner. The nature of the vibrations has not been closely defined yet and the mechanics are currently not properly understood. Conventional motorcycle-dynamics models are shown here to reveal the existence of a vibration mode that aligns with the experience being referred to, suggesting some explanations. Root loci for variations in speed or cornering vigour, demonstrating modal characteristics for small perturbations from trim states, are employed to indicate how the mode responds to changes in operation and design. Modal participation is examined for a lightly damped case. Influences on the natural frequency and damping of the mode are found and a way of stabilising the mode is suggested.

  3. Surface Vibration Reconstruction using Inverse Numerical Acoustics

    Directory of Open Access Journals (Sweden)

    F. Martinus

    2003-05-01

    Full Text Available This paper explores the use of inverse numerical acoustics to reconstruct the surface vibration of a noise source. Inverse numerical acoustics is mainly used for source identification. This approach uses the measured sound pressure at a set of field points and the Helmholtz integral equation to reconstruct the normal surface velocity. The number of sound pressure measurements is considerably less than the number of surface vibration nodes. An overview of inverse numerical acoustics is presented and compared with other holography techniques such as nearfield acoustical holography and the Helmholtz equation least squares method. In order to obtain an acceptable reproduction of the surface vibration, several critical factors such as the field point selection and the effect of experimental errors have to be handled properly. Other practical considerations such as the use of few measured velocities and regularization techniques will also be presented. Examples will include a diesel engine, a transmission housing and an engine cover.

  4. Diffusion of solid fuelon a vibrating grate

    DEFF Research Database (Denmark)

    Sabelström, Hanna Katarina

    of vibrations can be incorporated into a numerical model. The chosen model approach has been to separate the gas and solid phases into two independent models related to each other through the bed porosity. By treating the bed as a porous media and using Ergun's equation for the gas flow, the numerical work...... is simplified and the computational time shortened. The vibrations are affecting the transport and mixing of the fuel and incorporated into the model through the diffusion coefficient in the conservation equation of the solid phase. Experimental work has been carried out with the aim to study the behaviour...... of wood pellets on a vibrating grate and deriving the diffusion coefficient to be used in the numerical model. Three different grate designs are used and the particle trajectories have been captured by a camera placed above the grate. The diffusion coefficient is defined as the deviation from the mean...

  5. Transverse vibration of nematic elastomer Timoshenko beams.

    Science.gov (United States)

    Zhao, Dong; Liu, Ying; Liu, Chuang

    2017-01-01

    Being a rubber-like liquid crystalline elastomer, a nematic elastomer (NE) is anisotropic viscoelastic, and displays dynamic soft elasticity. In this paper, the transverse vibration of a NE Timoshenko beam is studied based on the linear viscoelasticity theory of nematic elastomers. The governing equation of motion for the transverse vibration of a NE Timoshenko beam is derived. A complex modal analysis method is used to obtain the natural frequencies and decrement coefficients of NE beams. The influences of the nematic director rotation, the rubber relaxation time, and the director rotation time on the vibration characteristic of NE Timoshenko beams are discussed in detail. The sensitivity of the dynamic performance of NE beams to director initial angle and relaxation times provides a possibility of intelligent controlling of their dynamic performance.

  6. Vibration Based Sun Gear Damage Detection

    Science.gov (United States)

    Hood, Adrian; LaBerge, Kelsen; Lewicki, David; Pines, Darryll

    2013-01-01

    Seeded fault experiments were conducted on the planetary stage of an OH-58C helicopter transmission. Two vibration based methods are discussed that isolate the dynamics of the sun gear from that of the planet gears, bearings, input spiral bevel stage, and other components in and around the gearbox. Three damaged sun gears: two spalled and one cracked, serve as the focus of this current work. A non-sequential vibration separation algorithm was developed and the resulting signals analyzed. The second method uses only the time synchronously averaged data but takes advantage of the signal/source mapping required for vibration separation. Both algorithms were successful in identifying the spall damage. Sun gear damage was confirmed by the presence of sun mesh groups. The sun tooth crack condition was inconclusive.

  7. Simple shearing interferometer suitable for vibration measurements

    Science.gov (United States)

    Mihaylova, Emilia M.; Whelan, Maurice P.; Toal, Vincent

    2004-06-01

    Recently there has been an increasing interest in the application of shearography for modal analysis of vibrating objects. New interferometric systems, which are simple and flexible are of interest for engineering and industrial applications. An electronic speckle pattern shearing interferometer (ESPSI) with a very simple shearing device is used for study of vibrations. The shearing device consists of two partially reflective glass plates. The reflection coefficients of the coatings are 0.3 and 0.7 respectively. The distance between the two glass plates controls the size of the shear. The versatility of this simple shearing interferometer is shown. It is demonstrated that the ESPSI system can be used for vibration measurements and phase-shifting implemented for fringe analysis. The results obtained are promising for future applications of the system for modal analysis.

  8. Acoustic vibration can enhance bacterial biofilm formation.

    Science.gov (United States)

    Murphy, Mark F; Edwards, Thomas; Hobbs, Glyn; Shepherd, Joanna; Bezombes, Frederic

    2016-12-01

    This paper explores the use of low-frequency-low-amplitude acoustic vibration on biofilm formation. Biofilm development is thought to be governed by a diverse range of environmental signals and much effort has gone into researching the effects of environmental factors including; nutrient availability, pH and temperature on the growth of biofilms. Many biofilm-forming organisms have evolved to thrive in mechanically challenging environments, for example soil yet, the effects of the physical environment on biofilm formation has been largely ignored. Exposure of Pseudomonas aeruginosa to vibration at 100, 800 and 1600 Hz for 48 h, resulted in a significant increase in biofilm formation compared with the control, with the greatest growth seen at 800 Hz vibration. The results also show that this increase in biofilm formation is accompanied with an increase in P. aeruginosa cell number. Acoustic vibration was also found to regulate the spatial distribution of biofilm formation in a frequency-dependent manner. Exposure of Staphylococcus aureus to acoustic vibration also resulted in enhanced biofilm formation with the greatest level of biofilm being formed following 48 h exposure at 1600 Hz. These results show that acoustic vibration can be used to control biofilm formation and therefore presents a novel and potentially cost effective means to manipulate the development and yield of biofilms in a range of important industrial and medical processes. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  9. Lambda-matrices and vibrating systems

    CERN Document Server

    Lancaster, Peter; Stark, M; Kahane, J P

    1966-01-01

    Lambda-Matrices and Vibrating Systems presents aspects and solutions to problems concerned with linear vibrating systems with a finite degrees of freedom and the theory of matrices. The book discusses some parts of the theory of matrices that will account for the solutions of the problems. The text starts with an outline of matrix theory, and some theorems are proved. The Jordan canonical form is also applied to understand the structure of square matrices. Classical theorems are discussed further by applying the Jordan canonical form, the Rayleigh quotient, and simple matrix pencils with late

  10. Free vibrations of circular cylindrical shells

    CERN Document Server

    Armenàkas, Anthony E; Herrmann, George

    1969-01-01

    Free Vibrations of Circular Cylindrical Shells deals with thin-walled structures that undergo dynamic loads application, thereby resulting in some vibrations. Part I discusses the treatment of problems associated with the propagation of plane harmonic waves in a hollow circular cylinder. In such search for solutions, the text employs the framework of the three-dimensional theory of elasticity. The text explains the use of tables of natural frequencies and graphs of representative mode shapes of harmonic elastic waves bounding in an infinitely long isotropic hollow cylinder. The tables are

  11. Multiaxis Rainflow Fatigue Methods for Nonstationary Vibration

    Science.gov (United States)

    Irvine, T.

    2016-01-01

    Mechanical structures and components may be subjected to cyclical loading conditions, including sine and random vibration. Such systems must be designed and tested accordingly. Rainflow cycle counting is the standard method for reducing a stress time history to a table of amplitude-cycle pairings prior to the Palmgren-Miner cumulative damage calculation. The damage calculation is straightforward for sinusoidal stress but very complicated for random stress, particularly for nonstationary vibration. This paper evaluates candidate methods and makes a recommendation for further study of a hybrid technique.

  12. Resonant vibration control of wind turbine blades

    DEFF Research Database (Denmark)

    Svendsen, Martin Nymann; Krenk, Steen; Høgsberg, Jan Becker

    2010-01-01

    The paper deals with introduction of damping to specific vibration modes of wind turbine blades, using a resonant controller with acceleration feedback. The wind turbine blade is represented by three-dimensional, two-node finite elements in a local, rotating frame of reference. The element....... The efficiency of the resonant controller is demonstrated for a representative turbine blade exposed to turbulent wind loading. It is found that the present explicit tuning procedure yields close to optimal tuning, with very limited modal spill-over and effective reduction of the vibration amplitudes....

  13. Vibrational Based Inspection Of A Steel Mast

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Rytter, A.

    1994-01-01

    The aim of this paper is to present the results from a research project concerning vibrational based inspection of a 20 meter high steel mast containing well defined damages. Introductory analyses dealing with among other things evaluation of potential damage indicators and determination of accep......The aim of this paper is to present the results from a research project concerning vibrational based inspection of a 20 meter high steel mast containing well defined damages. Introductory analyses dealing with among other things evaluation of potential damage indicators and determination...

  14. Localized Surface Plasmons in Vibrating Graphene Nanodisks

    DEFF Research Database (Denmark)

    Wang, Weihua; Li, Bo-Hong; Stassen, Erik

    2016-01-01

    in graphene disks have the additional benefit to be highly tunable via electrical stimulation. Mechanical vibrations create structural deformations in ways where the excitation of localized surface plasmons can be strongly modulated. We show that the spectral shift in such a scenario is determined...... by a complex interplay between the symmetry and shape of the modal vibrations and the plasmonic mode pattern. Tuning confined modes of light in graphene via acoustic excitations, paves new avenues in shaping the sensitivity of plasmonic detectors, and in the enhancement of the interaction with optical emitters...

  15. Optical Measurement of Cable and String Vibration

    Directory of Open Access Journals (Sweden)

    Y. Achkire

    1998-01-01

    Full Text Available This paper describes a non contacting measurement technique for the transverse vibration of small cables and strings using an analog position sensing detector. On the one hand, the sensor is used to monitor the cable vibrations of a small scale mock-up of a cable structure in order to validate the nonlinear cable dynamics model. On the other hand, the optical sensor is used to evaluate the performance of an active tendon control algorithm with guaranteed stability properties. It is demonstrated experimentally, that a force feedback control law based on a collocated force sensor measuring the tension in the cable is feasible and provides active damping in the cable.

  16. Noise and vibration in friction systems

    CERN Document Server

    Sergienko, Vladimir P

    2015-01-01

    The book analyzes the basic problems of oscillation processes and theoretical aspects of noise and vibration in friction systems. It presents generalized information available in literature data and results of the authors in vibroacoustics of friction joints, including car brakes and transmissions. The authors consider the main approaches to abatement of noise and vibration in non-stationary friction processes. Special attention is paid to materials science aspects, in particular to advanced composite materials used to improve the vibroacoustic characteristics of tribopairs The book is intended for researchers and technicians, students and post-graduates specializing in mechanical engineering, maintenance of machines and transport means, production certification, problems of friction and vibroacoustics.

  17. Free vibration of arches flexible in shear.

    Science.gov (United States)

    Austin, W. J.; Veletsos, A. S.

    1973-01-01

    An analysis reported by Veletsos et al. (1972) concerning the free vibrational characteristics of circular arches vibrating in their own planes is considered. The analysis was based on a theory which neglects the effects of rotatory inertia and shearing deformation. A supplementary investigation is conducted to assess the effects of the previously neglected factors and to identify the conditions under which these effects are of practical significance or may be neglected. A simple approximate procedure is developed for estimating the natural frequencies of arches, giving due consideration to the effects of the previously neglected factors.

  18. Vibration-based testing of bolted joints

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel; Sah, Si Mohamed; Fidlin, Alexander

    2017-01-01

    In recent pilot studies we have started investigating how to possibly use measured flexural (i.e. transverse/bending) vibrations, induced by bolt-tapping, to estimate bolt tightness. Some of the vibration features we investigated showed strong correlation with bolt tightness. For example, the low...... to bolt tension, but also to slenderness ratio. Thus, if only the natural frequency feature were to be used for estimating bolt tension, accuracy will drop off for the short and thick bolts that are often used in critical joints....

  19. Design of Wind Turbine Vibration Monitoring System

    Directory of Open Access Journals (Sweden)

    Shoubin Wang

    2013-04-01

    Full Text Available In order to ensure safety of wind turbine operation and to reduce the occurrence of faults as well as to improve the reliability of wind turbine operation, a vibration monitoring for wind turbine is developed. In this paper, it analyses the enlargement of all the parts of the structure and the working mechanism, the research method of wind turbine operation vibration is introduced, with the focus being the use of the sensor principle. Finally the hardware design and software of this system is introduced and the main function of this system is described, which realizes condition monitoring of the work state of wind turbines.

  20. Multiaxis Rainflow Fatigue Methods for Nonstationary Vibration

    Science.gov (United States)

    Irvine, T.

    2016-09-01

    Mechanical structures and components may be subjected to cyclical loading conditions, including sine and random vibration. Such systems must be designed and tested according. Rainflow cycle counting is the standard method for reducing a stress time history to a table of amplitude-cycle pairings prior to the Palmgren-Miner cumulative damage calculation. The damage calculation is straightforward for sinusoidal stress but very complicated for random stress, particularly for nonstationary vibration. This paper evaluates candidate methods and makes a recommendation for further study of a hybrid technique.

  1. EFFECT OF A SHORT PERIOD WHOLE BODY VIBRATION WITH 10 HZ ON BLOOD BIOMARKERS IN WISTAR RATS.

    Science.gov (United States)

    Monteiro, Milena de Oliveira Bravo; de Sá-Caputo, Danúbia da Cunha; Moreira-Marconi, Eloá; Frederico, Éric Heleno Freire Ferreira; de Sousa-Gonçalves, Cintia Renata; Bernardo, Luciana Camargo; Guimarães, Carlos Alberto Sampaio; Bernardo-Filho, Mario

    2017-01-01

    Exposure to whole body vibration exercises (WBVE), besides some biological effects, causes alterations in the concentration of some blood biomarkers. The aim of this study is to evaluate the action of vibration (10 Hz) of WBVE on the concentration of blood biomarkers in Wistar rats. Wistar rats were divided in 2 groups. The experimental group (EG) was subjected to vibrations of 10Hz (one min per day, one week, total time of seven min), while the control group (CG) has not experienced vibration. Samples of whole blood were drawn for biochemical analysis of the concentration of total cholesterol, triglycerides, HDL, LDL, VLDL, glucose, CPK, albumin, alkaline phosphates, TGP, TGO, γGT, lipase, amylase, urea and creatinine. White blood cell count and a platelet-hemogram were also performed. Significant (pvibration. Although these findings were obtained with rats, they might contribute to try to understand better these mechanisms that occur following exposure to a frequency of 10Hz.

  2. Bearings Fault Diagnosis Based on Convolutional Neural Networks with 2-D Representation of Vibration Signals as Input

    Directory of Open Access Journals (Sweden)

    Zhang Wei

    2017-01-01

    Full Text Available Periodic vibration signals captured by the accelerometers carry rich information for bearing fault diagnosis. Existing methods mostly rely on hand-crafted time-consuming preprocessing of data to acquire suitable features. In this paper, we use an easy and effective method to transform the 1-D temporal vibration signal into a 2-D image. With the signal image, convolutional Neural Network (CNN is used to train the raw vibration data. As powerful feature extractor and classifier for image recognition, CNN can learn to acquire features most suitable for the classification task by being trained. With the image format of vibration signals, the neuron in fully-connected layer of CNN can see farther and capture the periodic feature of signals. According to the results of the experiments, when fed in enough training samples, the proposed method outperforms other common methods. The proposed method can also be applied to solve intelligent diagnosis problems of other machine systems.

  3. Broadband vibration energy harvester utilizing three out-of-plane modes of one vibrating body

    Science.gov (United States)

    Park, Shi-Baek; Jang, Seon-Jun; Kim, In-Ho; Choi, Yong Je

    2017-10-01

    In this paper, we introduce the concept, design equation, and realization of a broadband electromagnetic vibrational energy harvester. The spatial vibrating system in the proposed harvester is arranged to have three out-of-plane vibration modes. We devise the design method for its three natural frequencies and accompanying modes and apply it to the broadband energy harvesting by locating three frequencies close to each other. The numerical simulation and the experimental results show that it satisfies the designated frequencies as well as the enhanced bandwidth for power generation.

  4. Integrated predictive maintenance program vibration and lube oil analysis: Part I - history and the vibration program

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, H.

    1996-12-01

    This paper is the first of two papers which describe the Predictive Maintenance Program for rotating machines at the Palo Verde Nuclear Generating Station. The organization has recently been restructured and significant benefits have been realized by the interaction, or {open_quotes}synergy{close_quotes} between the Vibration Program and the Lube Oil Analysis Program. This paper starts with the oldest part of the program - the Vibration Program and discusses the evolution of the program to its current state. The {open_quotes}Vibration{close_quotes} view of the combined program is then presented.

  5. Electronic and magnetic properties study of neptunium compounds: NpX{sub 3} and Np{sub 2}T{sub 2}X by Moessbauer effect, neutrons diffraction and Squid magnetometry; Etude des proprietes magnetiques et electroniques de composes de neptunium NpX{sub 3} et Np{sub 2}T{sub 2}X par spectrometrie mossbauer, diffraction de neutrons et magnetometrie squid

    Energy Technology Data Exchange (ETDEWEB)

    Colineau, E.

    1996-07-11

    This work is a contribution to the study of magnetic and electronic properties of the intermetallic compounds: NpX{sub 3} (X= Al, Ga, In, Sn) and Np{sub 2}T{sub 2}X (T= Co, Ni, Ru, Rh, Pd, Pt; X= In, Sn). These properties have been determined by Moessbauer effect, neutron diffraction and Squid magnetometry. The obtained results for NpX{sub 3} show particularly that NpAl{sub 3} orders in a type II (k= 1/2 1/2 1/2) antiferromagnetic structure at T{sub N} {approx_equal} 37 K. The antiferromagnetic phase NpGa{sub 3} orders in a type II too and the magnetic moments carried by neptunium in the ferromagnetic phase are oriented along the (111) axes. The two NpIN{sub 3} magnetic phases observed by Moessbauer effect (4.2 K-10 K and 10 K- 14 K) are identified by neutron diffraction as ferromagnetic and antiferromagnetic (k= 3/8 3/8 3/8). In this last phase the moments are oriented along the (111) axes. The magnetization measures on monocrystals show a weak anisotropy with (111) at all the temperatures and reveal the presence of a third magnetic phase between 8.2 and 10 K. At last, the fundamental state of the compounds NpAl{sub 3}, NpGa{sub 3} and NpIn{sub 3} is attributed to the {Gamma}{sub 5} crystal field and the strong reduction of the ordered moment in NpSn{sub 3} to a Kondo effect. Concerning the Np{sub 2}T{sub 2}X compounds, the Moessbauer effect measures have revealed that eight of these compounds order and three do not order. (O.M.). 239 refs.

  6. The Shock Vibration Bulletin. Part 3. Isolation and Damping, Vibration Test Criteria, and Vibration Analysis and Test

    Science.gov (United States)

    1987-01-01

    fatigae equivalent test time of 45-mimates. 1. BACKGROUND subjected to both vibration and loose cargo testing as well an the type and amount of...Environmental Test the track laying environment. Nethods, 10 March 1975. 8. FUTURE EFFORTS 11. Soci, Darrell F., Fatigae Life Estimation Techniques, Technical

  7. Do Scaphoideus titanus (Hemiptera: Cicadellidae) nymphs use vibrational communication?

    Science.gov (United States)

    Chuche, Julien; Thiéry, Denis; Mazzoni, Valerio

    2011-07-01

    Small Auchenorrhyncha use substrate-borne vibrations to communicate. Although this behaviour is well known in adult leafhoppers, so far no studies have been published on nymphs. Here we checked the occurrence of vibrational communication in Scaphoideus titanus (Hemiptera: Cicadellidae) nymphs as a possible explanation of their aggregative distributions on host plants. We studied possible vibratory emissions of isolated and grouped nymphs, as well as their behavioural responses to vibration stimuli that simulated presence of conspecifics, to disturbance noise, white noise and predator spiders. None of our synthetic stimuli or pre-recorded substrate vibrations from nymphs elicited specific vibration responses and only those due to grooming or mechanical contacts of the insect with the leaf were recorded. Thus, S. titanus nymphs showed to not use species-specific vibrations neither for intra- nor interspecific communication and also did not produce alarm vibrations when facing potential predators. We conclude that their aggregative behaviour is independent from a vibrational communication.

  8. Alleviation of Buffet-Induced Vibration Using Piezoelectric Actuators

    National Research Council Canada - National Science Library

    Morgenstern, Shawn D

    2006-01-01

    .... The objective of this research was to determine the most critical natural modes of vibration for the F-16 ventral fin and design piezoelectric actuators capable of reducing buffet-induced ventral fin vibration...

  9. Coupled electromechanical model of an imperfect piezoelectric vibrating cylinder gyroscope

    CSIR Research Space (South Africa)

    Loveday, PW

    1996-01-01

    Full Text Available Coupled electromechanical equations of motion, describing the dynamics of a vibrating cylinder gyroscope, are derived using Hamilton's principle and the Rayleigh-Ritz method. The vibrating cylinder gyroscope comprises a thin walled steel cylinder...

  10. Evaluation of vibration limits and mitigation techniques for urban construction.

    Science.gov (United States)

    2013-10-01

    The overriding purpose of this research was to develop a comprehensive framework to address : vibration issues prior to and during construction, including calculation of anticipated ground : vibrations during project design, condition surveys of stru...

  11. Update LADOTD policy on pile driving vibration management.

    Science.gov (United States)

    2012-02-01

    The main objective of this project was to update the current Louisiana Department of Transportation and Development (LADOTD) policy on pile driving vibration risk management with a focus on how to determine an appropriate vibration monitoring area. T...

  12. Active vibration isolation of a rigidly mounted turbo pump

    NARCIS (Netherlands)

    Basten, T.G.H.; Doppenberg, E.J.J.

    2006-01-01

    Manufacturers of precision equipment are constantly aiming at increased accuracy. Elimination of disturbing vibrations is therefore getting more and more important. The technical limitations of passive isolation methods require alternative strategies for vibration reduction, such as active

  13. Self-excited and subharmonic vibrations in a pilot rotor

    Science.gov (United States)

    Kumenko, A. I.; Kostyukov, V. N.; Kuzminykh, N. Yu.; Timin, A. V.

    2017-08-01

    The paper reviews the publications on low-frequency vibration in power plants. It is noted that the regulatory literature poorly defines the issues of rating and diagnosing self-excited and subharmonic vibrations. Analysis of the literature and ISO standards shows that despite the considerable experience gained by specialists in low-frequency vibration control, a number of issues, such as subharmonic resonances and nonlinear properties of complicated multi-seated rotor systems supported by journal bearings, are still understudied and require further calculations and experiments. The paper presents some results obtained in experiments of low-frequency vibrations for a rotor supported by journal bearings and having a residual deflection. The experimental results confirmed the classical hysteresis of self-excited vibrations - the difference in the boundaries of self-excited vibrations during ascent and descent is about 4 Hz. The arears of appearance and disappearance of subharmonic vibrations are shown using the spectral characteristics of vibrations and cascade spectra.

  14. Language sampling

    DEFF Research Database (Denmark)

    Rijkhoff, Jan; Bakker, Dik

    1998-01-01

    This article has two aims: [1] to present a revised version of the sampling method that was originally proposed in 1993 by Rijkhoff, Bakker, Hengeveld and Kahrel, and [2] to discuss a number of other approaches to language sampling in the light of our own method. We will also demonstrate how our...... sampling method is used with different genetic classifications (Voegelin & Voegelin 1977, Ruhlen 1987, Grimes ed. 1997) and argue that —on the whole— our sampling technique compares favourably with other methods, especially in the case of exploratory research....

  15. Experimental Modal Analysis on Vibrations in the Building Construction

    OpenAIRE

    成瀬, 治興; 佐野, 泰之; 北畠, 弘基

    1996-01-01

    This paper describes some results of vibration propagation characteristics of two rooms next door to each other in the actual building construction (including floor, walls, and upstairfloor) by experimental modal analysis. In addition, we investigate about vibration response of measuring points by forced response and sensitivity analysis. The results are summarized as follows. The vibration of lower modes gives larger effect to vibration propagation characteristics of building construction th...

  16. Supplementary Information Table: S1 Calculated vibrational wave ...

    Indian Academy of Sciences (India)

    Administrator

    514. 511 w. 519 vvw. 6a ring o.p bend. 508. 496 s. 500 vvw. 16 b ring o.p bend. 390. 387 vvw. 16a ring o.p bend. 334. 328 vvw. 9b C-H i.p bend. 274. 267 vvw. Hydrogen bonded vibrations. 184. 171 vs. Hydrogen bonded vibrations. 112. 120 vvs. Hydrogen bonded vibrations. 64. 57 sh. Hydrogen bonded vibrations.

  17. Sound insulation and vibration tests for lightweight steel framing floors

    OpenAIRE

    Shi, Wanqing; Edfast, Fredrik; Ågren, Anders

    2000-01-01

    An experimental study of sound insulation and vibrations of lightweight steel framing floors due to different floor construction set up were performed. Floors with 3m, 5m and 7.2m span were tested. The impact and airborne sound insulation for 3m span floor were measured based on ISO 140 in lab condition. Vibration tests were carried out on all three different spans. The vibration transmission loss of the structure was determined from the surface vibration measurements. The fundamental natural...

  18. Wireless Module for Sensing Superficial Vibrations of Soils

    Directory of Open Access Journals (Sweden)

    Marlon R. Fulla

    2013-11-01

    Full Text Available In the present work, the feasibility of implementing the XBee technology in wireless accelerometric sensors (WAS development for sensing of elastic waves on soils surface is analyzed. The incidence of distance and obstacles between a coordinator and end-device pair in their radio link by examining the number of packets received successfully was verified. Additionally, it was investigated the influence of the transmission rate over the sampling frequency of signals associated to mechanical vibrations from a testing ground by measuring the effective sampling periods of the "A / D Conversion - Transmission" process. The data reception errors introduced by the channel attenuation and the presence of obstacles, impose severe restrictions on the maximum allowable distance between the communication modules. The transmission rate features provided by XBee technology in association with the A / D time sampling of the microcontroller, allow to carry out recordings to a maximum sampling frequency of 1 kHz , useful for real-time applications where seismic signals are into the spectral range 0 to 500 Hz. In order to increase the sampling frequency of the sensor for prospection applications with signals with bandwidths greater than 500 Hz , it was successfully tested a prototype that uses a fast external memory for storing data, which significantly improves the sampling signal allowing to retake XBee technology due to its excellent low consumption features.

  19. Venous Sampling

    Science.gov (United States)

    ... neck to help locate abnormally functioning glands or pituitary adenoma . This test is most often used after an unsuccessful neck exploration. Inferior petrosal sinus sampling , in which blood samples are taken from veins that drain the pituitary gland to study disorders related to pituitary hormone ...

  20. Sampling Development

    Science.gov (United States)

    Adolph, Karen E.; Robinson, Scott R.

    2011-01-01

    Research in developmental psychology requires sampling at different time points. Accurate depictions of developmental change provide a foundation for further empirical studies and theories about developmental mechanisms. However, overreliance on widely spaced sampling intervals in cross-sectional and longitudinal designs threatens the validity of…

  1. Language sampling

    DEFF Research Database (Denmark)

    Rijkhoff, Jan; Bakker, Dik

    1998-01-01

    This article has two aims: [1] to present a revised version of the sampling method that was originally proposed in 1993 by Rijkhoff, Bakker, Hengeveld and Kahrel, and [2] to discuss a number of other approaches to language sampling in the light of our own method. We will also demonstrate how our...

  2. A seismic vertical vibrator driven by linear motors

    NARCIS (Netherlands)

    Noorlandt, R.P.; Drijkoningen, G.G.; Schneider, R.M.

    2012-01-01

    In this paper we present a newly developed vertical seismic vibrator driven by linear motors. We explain the different components the vibrator consists of. We show that the harmonic distortion of the linear-motor vibrator signal is very small. We also show that, without applying a feedback loop on

  3. Molecular and vibrational structure of thiosulfonate S-esters

    DEFF Research Database (Denmark)

    Luu, Thi Xuan Thi; Duus, Fritz; Spanget-Larsen, Jens

    2013-01-01

    /cc-pVTZ). The vibrational spectra of 2 and 3 are sensitive to the orientation of the alkyl group attached to the sulfonylic sulfur atom. Rotamers corresponding to anti and gauche conformations are thus predicted to have distinctly different vibrational transitions in the 800–400 cm–1 region. The observed vibrational...

  4. A novel technique for active vibration control, based on optimal ...

    Indian Academy of Sciences (India)

    In the last few decades, researchers have proposed many control techniques to suppress unwanted vibrations in a structure. In this work, a novel and simple technique is proposed for the active vibration control. In this technique, an optimal tracking control is employed to suppress vibrations in a structure by simultaneously ...

  5. 47 CFR 10.530 - Common vibration cadence.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Common vibration cadence. 10.530 Section 10.530... § 10.530 Common vibration cadence. A Participating CMS Provider and equipment manufacturers may only market devices for public use under part 10 that include a vibration cadence capability that meets the...

  6. Vibration for Pain Reduction in a Plastic Surgery Clinic.

    Science.gov (United States)

    Eichhorn, Mitchell George; Karadsheh, Murad Jehad; Krebiehl, Johanna Ruth; Ford, Dawn Marie; Ford, Ronald D

    2016-01-01

    Patients can experience significant pain during routine procedures in the plastic surgery clinic. Methods for clinical pain reduction are often impractical, time-consuming, or ineffective. Vibration is a safe, inexpensive, and highly applicable modality for pain reduction that can be readily utilized for a wide variety of procedures. This study evaluated the use of vibration as a viable pain-reduction strategy in the clinical plastic surgery setting. Patients requiring at least 2 consecutive procedures that are considered painful were enrolled in the study. These included injections, staple removal, and suture removal. In the same patient, one half of the procedures were performed without vibration and the other half with vibration. After completing the procedures, the patients rated their pain with vibration and without vibration. The patient and the researcher also described the experience with a short questionnaire. Twenty-eight patients were enrolled in the study. Patients reported significantly less pain on the Numeric Rating Scale pain scale when vibration was used compared with the control group (p vibration and 1.93 with vibration, and vibration with injections resulted in the greatest improvement. Eighty-six percent of the patients claimed that vibration significantly reduced their pain. Vibration is an effective method of pain reduction. It significantly reduces the pain experienced by patients during minor office procedures. Given its practicality and ease of use, it is a welcome tool in the plastic surgery clinic.

  7. A novel technique for active vibration control, based on optimal ...

    Indian Academy of Sciences (India)

    BEHROUZ KHEIRI SARABI

    2017-07-11

    Jul 11, 2017 ... Abstract. In the last few decades, researchers have proposed many control techniques to suppress unwanted vibrations in a structure. In this work, a novel and simple technique is proposed for the active vibration control. In this technique, an optimal tracking control is employed to suppress vibrations in a ...

  8. 46 CFR 162.050-37 - Vibration test.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Vibration test. 162.050-37 Section 162.050-37 Shipping...: SPECIFICATIONS AND APPROVAL ENGINEERING EQUIPMENT Pollution Prevention Equipment § 162.050-37 Vibration test. (a... and each control of a separator must be subjected to continuous sinusoidal vibration in each of the...

  9. Whole body vibration improves attention and motor performance in ...

    African Journals Online (AJOL)

    Background: Whole body vibration (WBV) is a form of physical stimulation via mechanical vibrations transmitted to a subject. It is assumed that WBV induces sensory stimulation in cortical brain regions through the activation of skin and muscle receptors responding to the vibration. The effects of WBV on muscle strength are ...

  10. VIBRATION ANALYSIS OF LOW-ASPECT RATIO ROTATING ...

    African Journals Online (AJOL)

    vibrations. And the program developed may be used to include other design characteristics by way of refining the blade modeling. REFERENCES. [1] Campbell,W., "Tangential Vibration of Steam. Turbine Buckets." Trans. of ASME, pp. 643 -. 671, 1924. [2] Lo, H.; RenbargerJ.L.; "Bending Vibration of a Rotating Beams." Proc ...

  11. Vibrational Relaxation in Neat Crystals of Naphthalene by Picosecond CARS

    NARCIS (Netherlands)

    Hesp, Ben H.; Wiersma, Douwe A.

    1980-01-01

    Picosecond delayed CARS experiments on totally symmetric modes in naphthalene at 1.5 K are reported. The Raman lineshape of the vibrational excitons is lorentzian and vibrational relaxation can be surprisingly slow. The Raman lineshape of the Ag exciton level of the 766 cm-1 vibrational mode reveals

  12. Three-dimensional free vibration analysis of thick laminated circular ...

    African Journals Online (AJOL)

    Dr Oke

    mechanical systems is understanding the free vibration behavior of different plate components. The dynamic response of complex engineering systems is intimately linked with plate response frequencies as well as vibration mode shapes. A thorough analysis of free vibration data is often useful in arriving at the resonant ...

  13. Estimation of spinal loading in vertical vibrations by numerical simulation

    NARCIS (Netherlands)

    Verver, M.M.; Hoof, J.F.A.M. van; Oomens, C.W.J.; Wouw, N. van de; Wismans, J.S.H.M.

    2003-01-01

    Objective. This paper describes the prediction of spinal forces in car occupants during vertical vibrations using a numerical multi-body occupant model. Background. An increasing part of the population is exposed to whole body vibrations in vehicles. In literature, vertical vibrations and low back

  14. Numerical Modelling of Rubber Vibration Isolators: identification of material parameters

    NARCIS (Netherlands)

    Beijers, C.A.J.; Noordman, Bram; de Boer, Andries; Ivanov, N.I.; Crocker, M.J.

    2004-01-01

    Rubber vibration isolators are used for vibration isolation of engines at high frequencies. To make a good prediction regarding the characteristics of a vibration isolator in the design process, numerical models can be used. However, for a reliable prediction of the dynamic behavior of the isolator,

  15. Effect of vibration stabilization of the process of postcritical deformation

    Science.gov (United States)

    Wildemann, V. E.; Lomakin, E. V.; Tretyakov, M. P.

    2016-03-01

    Results of the experimental study of vibration stabilization of the process of postcritical deformation during the tensile testing of solid cylindrical specimens made of 20 and 40Cr structural steels under additional vibrations are presented. The vibrations are implemented using cyclic torsion of the specimens at a small amplitude and a frequency of 10-30 Hz.

  16. Finite Element Vibration Analysis of Beams, Plates and Shells

    Directory of Open Access Journals (Sweden)

    Jaroslav Mackerle

    1999-01-01

    Full Text Available This bibliography lists references to papers, conference proceedings and theses/dissertations dealing with finite element vibration analysis of beams, plates and shells that were published in 1994–1998. It contains 361 citations. Also included, as separated subsections, are vibration analysis of composite materials and vibration analysis of structural elements with cracks/contacts.

  17. DOE/ANL/HTRI heat exchanger tube vibration data bank

    Energy Technology Data Exchange (ETDEWEB)

    Halle, H.; Chenoweth, J.M.; Wambsganss, M.W.

    1981-01-01

    This addendum to the DOE/ANL/HTRI Heat Exchanger Tube Vibration Data Bank includes 16 new case histories of field experiences. The cases include several exchangers that did not experience vibration problems and several for which acoustic vibration was reported.

  18. Environmental sampling

    Energy Technology Data Exchange (ETDEWEB)

    Puckett, J.M.

    1998-12-31

    Environmental Sampling (ES) is a technology option that can have application in transparency in nuclear nonproliferation. The basic process is to take a sample from the environment, e.g., soil, water, vegetation, or dust and debris from a surface, and through very careful sample preparation and analysis, determine the types, elemental concentration, and isotopic composition of actinides in the sample. The sample is prepared and the analysis performed in a clean chemistry laboratory (CCL). This ES capability is part of the IAEA Strengthened Safeguards System. Such a Laboratory is planned to be built by JAERI at Tokai and will give Japan an intrinsic ES capability. This paper presents options for the use of ES as a transparency measure for nuclear nonproliferation.

  19. Vibration-induced PM Noise in Oscillators and Measurements of Correlation with Vibration Sensors

    National Research Council Canada - National Science Library

    Howe, D. A; LanFranchi, J. L; Cutsinger, L; Hati, A; Nelson, C

    2005-01-01

    ...) and acceleration/vibration sensors. We describe the equipment setup and measurement procedure. Data are in the form of scatter plots, which we find to be highly informative compared to usual L(f...

  20. Vibration modes and frequencies of structures

    Science.gov (United States)

    Durling, R. J.; Kvaternik, R. G.

    1980-01-01

    SUDAN, Substructuring in Direct Analysis, analyzes natural modes and frequencies of vibration of structural systems. Based on direct method of analysis that employs substructures methodology, program is used with structures that may be represented as equivalent system of beam, springs, and rigid bodies.

  1. Index to the Shock and Vibration Bulletins

    Science.gov (United States)

    1968-02-01

    See Welmers , E, TJ. 24(14) S SAIN, W. H. Mechanical properties of special tubes under high acceleration, 24(195) SANDERS, S. P. Pneumatic...resistance strain gages. 8(1) WELLER, R. K. Methods of achieving missile reliability. 18(9) WELMERS , E. T, Missile vibrations and instrumentation. 18

  2. Composite materials inspection. [ultrasonic vibration holographic NDT

    Science.gov (United States)

    Erf, R. K.

    1974-01-01

    Investigation of the application requirements, advantages, and limitations of nondestructive testing by a technique of ultrasonic-vibration holographic-interferometry readout used in a production control facility for the inspection of a single product such as composite compressor blades. It is shown that, for the detection and characterization of disbonds in composite material structures, this technique may represent the most inclusive test method.

  3. Wind-induced vibration of stay cables

    Science.gov (United States)

    2007-08-01

    Cable-stayed bridges have become the form of choice over the past several decades for bridges in the medium- to long-span range. In some cases, serviceability problems involving large amplitude vibrations of stay cables under certain wind and rain co...

  4. Lambda-matrices and vibrating systems

    CERN Document Server

    Lancaster, Peter

    2002-01-01

    Features aspects and solutions of problems of linear vibrating systems with a finite number of degrees of freedom. Starts with development of necessary tools in matrix theory, followed by numerical procedures for relevant matrix formulations and relevant theory of differential equations. Minimum of mathematical abstraction; assumes a familiarity with matrix theory, elementary calculus. 1966 edition.

  5. Structural, intramolecular hydrogen bonding and vibrational studies ...

    Indian Academy of Sciences (India)

    An extensive theoretical study on the molecular structure and vibrational analysis of 3-amino-4- methoxy benzamide (3A4MBA) was undertaken using density functional theoretical (DFT) method. The possibility of formation of intramolecular hydrogen bonding was identified from structural parameter analysis and confirmed ...

  6. Vibrational resonance in the Morse oscillator

    Indian Academy of Sciences (India)

    Abstract. The occurrence of vibrational resonance is investigated in both classical and quantum mechanical Morse oscillators driven by a biharmonic force. The biharmonic force consists of two forces of widely different frequencies ω and with. ≫ ω. In the damped and biharmoni- cally driven classical Morse oscillator, ...

  7. Phase diagram of vertically vibrated dense suspensions

    NARCIS (Netherlands)

    von Kann, S.; Snoeijer, Jacobus Hendrikus; van der Meer, Roger M.

    2014-01-01

    When a hole is created in a layer of a dense, vertically vibrated suspension, phenomena are known to occur that defy the natural tendency of gravity to close the hole. Here, an overview is presented of the different patterns that we observed in a variety of dense particulate suspensions.

  8. Vibrations of a pipe on elastic foundations

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    is investigated. Two cases of elastic foundations are considered: rotational and both linear and rotational. The major findings are the variations in frequency with flow velocity and displacements at different points and times. Keywords. Cantilevered pipe; vibrations of pipes; elastic foundations; exter- nal transverse force. 1.

  9. Vibration Measurements on the Frejlev Mast

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Hansen, Lars Pilegaard

    The present report presents full-scale measurements on the Frejlev-mast which is a 200 meter hight guyed steel mast located 10 km. from Aalborg. The goal of the research was to investigate various techniques which could be used to estimate cable forces from vibration measurements. The cables...

  10. Using periodicity to mitigate ground vibration

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard

    2015-01-01

    Introduction of trenches, barriers and wave impeding blocks on the transmission path between a source and receiver can be used for mitigation of ground vibration. However, to be effective a barrier must have a depth of about one wavelength of the waves to be mitigated. Hence, while great reductions...

  11. Flexural vibrations of finite composite poroelastic cylinders

    Indian Academy of Sciences (India)

    Abstract. This paper deals with the flexural vibrations of composite poroelastic solid cylinder consisting of two cylinders that are bonded end to end. Poroelastic materials of the two cylinders are different. The frequency equations for pervious and impervious surfaces are obtained in the framework of Biot's theory of wave.

  12. Nonlinear Vibration of a Magnetic Spring

    Science.gov (United States)

    Zhong, Juhua; Cheng, Zhongqi; Ge, Ziming; Zhang, Yuelan; Lu, Wenqiang; Song, Feng; Li, Chuanyong

    2012-01-01

    To demonstrate the different vibration characteristics of a magnetic spring compared with those of a metal one, a magnetic spring apparatus was constructed from a pair of circular magnets of the same size with an inside diameter of 2.07 cm and an outside diameter of 4.50 cm. To keep the upper magnet in a suspension state, the two magnets were…

  13. Longitudinal shear vibrations of composite poroelastic cylinders ...

    African Journals Online (AJOL)

    Employing Biot's theory of wave propagation in liquid saturated porous media, longitudinal shear vibrations of composite poroelastic cylinders of infinite extent are investigated. The composite poroelastic cylinder is made of two different poroelastic materials. The dilatations of liquid and solid media are zero, hence liquid ...

  14. Probability of Failure in Random Vibration

    DEFF Research Database (Denmark)

    Nielsen, Søren R.K.; Sørensen, John Dalsgaard

    1988-01-01

    Close approximations to the first-passage probability of failure in random vibration can be obtained by integral equation methods. A simple relation exists between the first-passage probability density function and the distribution function for the time interval spent below a barrier before out...

  15. Damage Detection by Laser Vibration Measurement

    Directory of Open Access Journals (Sweden)

    Elena Daniela Birdeanu

    2008-10-01

    Full Text Available The technique based on the vibration analysis by scanning laser Doppler vibrometer is one of the most promising, allowing to extract also small defect and to directly correlate it to local dynamic stiffness and structural integrity. In fact, the measurement capabilities of vibrometers, such as sensitivity, accuracy and reduced intrusively, allow having a very powerful instrument in diagnostic.

  16. Vibration analysis of an elevated railway track

    NARCIS (Netherlands)

    Courage, W.M.G.; Staalduinen, P.C. van; Ruiter, B. de

    1996-01-01

    The results of a study are described with respect to the vibration analysis of an elevated railway track. In this study a numerical model was developed. This model is validated and tuned by means of measurements. For a new elevated railway track in design stage, the model is used for calculating the

  17. Analysis of real-time vibration data

    Science.gov (United States)

    Safak, E.

    2005-01-01

    In recent years, a few structures have been instrumented to provide continuous vibration data in real time, recording not only large-amplitude motions generated by extreme loads, but also small-amplitude motions generated by ambient loads. The main objective in continuous recording is to track any changes in structural characteristics, and to detect damage after an extreme event, such as an earthquake or explosion. The Fourier-based spectral analysis methods have been the primary tool to analyze vibration data from structures. In general, such methods do not work well for real-time data, because real-time data are mainly composed of ambient vibrations with very low amplitudes and signal-to-noise ratios. The long duration, linearity, and the stationarity of ambient data, however, allow us to utilize statistical signal processing tools, which can compensate for the adverse effects of low amplitudes and high noise. The analysis of real-time data requires tools and techniques that can be applied in real-time; i.e., data are processed and analyzed while being acquired. This paper presents some of the basic tools and techniques for processing and analyzing real-time vibration data. The topics discussed include utilization of running time windows, tracking mean and mean-square values, filtering, system identification, and damage detection.

  18. Free-Vibration Analysis of Structures

    Science.gov (United States)

    Gupta, K. K.

    1984-01-01

    Unified numerical procedure for free-vibration analysis of structures developed and incorporated into EIGSOL computer program. Dynamic response analysis of primary importance in design of wide range of practical structures such as space-craft, buildings, and rotating machineries. Procedure determines natural frequencies and associated modes in structural design.

  19. Emitted vibration measurement device and method

    Science.gov (United States)

    Gisler, G. L.

    1986-10-01

    This invention is directed to a method and apparatus for measuring emitted vibrational forces produced by a reaction wheel assembly due to imbalances, misalignment, bearing defects and the like. The apparatus includes a low mass carriage supported on a large mass base. The carriage is in the form of an octagonal frame having an opening which is adapted for receiving the reaction wheel assembly supported thereon by means of a mounting ring. The carriage is supported on the base by means of air bearings which support the carriage in a generally frictionless manner when supplied with compressed air from a source. A plurality of carriage brackets and a plurality of base blocks provided for physical coupling of the base and carriage. The sensing axes of the load cells are arranged generally parallel to the base and connected between the base and carriage such that all of the vibrational forces emitted by the reaction wheel assembly are effectively transmitted through the sensing axes of the load cells. In this manner, a highly reliable and accurate measurment of the vibrational forces of the reaction wheel assembly can be had. The output signals from the load cells are subjected to a dynamical analyzer which analyzes and identifies the rotor and spin bearing components which are causing the vibrational forces.

  20. Internal Temperature Control For Vibration Testers

    Science.gov (United States)

    Dean, Richard J.

    1996-01-01

    Vibration test fixtures with internal thermal-transfer capabilities developed. Made of aluminum for rapid thermal transfer. Small size gives rapid response to changing temperatures, with better thermal control. Setup quicker and internal ducting facilitates access to parts being tested. In addition, internal flows smaller, so less energy consumed in maintaining desired temperature settings.

  1. Free-Vibration Analysis of Structures

    Science.gov (United States)

    Gupta, K. K.

    1985-01-01

    Improved numerical procedure more than twice as fast as previous methods. Unified numerical algorithm efficiently solves free-vibration problems of stationary or spinning structures with or without viscous or structural damping. Algorithm used to solve static problems involving multiple loads and to solve quadratic matrix eigenvalue problems associated with finite-dynamic-element structural discretization.

  2. Smart paint sensor for monitoring structural vibrations

    Science.gov (United States)

    Al-Saffar, Y.; Aldraihem, O.; Baz, A.

    2012-04-01

    A class of smart paint sensors is proposed for monitoring the structural vibration of beams. The sensor is manufactured from an epoxy resin which is mixed with carbon black nano-particles to make it electrically conducting and sensitive to mechanical vibrations. A comprehensive theoretical and experimental investigation is presented to understand the underlying phenomena governing the operation of this class of paint sensors and evaluate its performance characteristics. A theoretical model is presented to model the electromechanical behavior of the sensor system using molecular theory. The model is integrated with an amplifier circuit in order to predict the current and voltage developed by the paint sensor when subjected to loading. Furthermore, the sensor/amplifier circuit models are coupled with a finite element model of a base beam to which the sensor is bonded. The resulting multi-field model is utilized to predict the behavior of both the sensor and the beam when subjected to a wide variety of vibration excitations. The predictions of the multi-field finite element model are validated experimentally and the behavior of the sensor is evaluated both in the time and the frequency domains. The performance of the sensor is compared with the performance of conventional strain gages to emphasize its potential and merits. The presented techniques are currently being extended to sensors that can monitor the vibration and structural power flow of two-dimensional structures.

  3. Laserlike Vibrational Instability in Rectifying Molecular Conductors

    DEFF Research Database (Denmark)

    Lu, Jing Tao; Hedegård, Per; Brandbyge, Mads

    2011-01-01

    We study the damping of molecular vibrations due to electron-hole pair excitations in donor-acceptor (D-A) type molecular rectifiers. At finite voltage additional nonequilibrium electron-hole pair excitations involving both electrodes become possible, and contribute to the stimulated emission and...

  4. Succesful teaching of experimental vibration research

    NARCIS (Netherlands)

    Wolbert, Bert; van der Hoogt, Peter; Lok, Zacharias A.J.; de Boer, Andries

    For more than 20 years, master students have been offered a practical training on experimental vibration research by the Structural Dynamics & Acoustics Section of the University of Twente. The basic theoretical knowledge, necessary to attend this practical training, is provided for the Master part

  5. Optimal control of vibrational transitions of HCl

    Indian Academy of Sciences (India)

    Control of fundamental and overtone transitions of a vibration are studied for the diatomic molecule, HCl. Specifically, the results of the effect of variation of the penalty factor on the physical attributes of the system (i.e., probabilities) and pulse (i.e., amplitudes) considering three different pulse durations for each value of the ...

  6. Vibration Analysis of AN Induction Motor

    Science.gov (United States)

    WANG, C.; LAI, J. C. S.

    1999-07-01

    With the advent of power electronics, variable speed induction motors are finding increasing use in industries because of their low cost and potential savings in energy consumption. However, the acoustic noise emitted by the motor increases due to switching harmonics introduced by the electronic inverters. Consequently, the vibro-acoustic behaviour of the motor structure has attracted more attention. In this paper, considerations given to modelling the vibration behaviour of a 2·2 kW induction motor are discussed. By comparing the calculated natural frequencies and the mode shapes with the results obtained from experimental modal testing, the effects of the teeth of the stator, windings, outer casing, slots, end-shields and support on the overall vibration behaviour are analyzed. The results show that when modelling the vibration behaviour of a motor structure, the laminated stator should be treated as an orthotropic structure, and the teeth of the stator could be neglected. As the outer casing, end-shields and the support all affect the vibration properties of the whole structure, these substructures should be incorporated in the model to improve the accuracy.

  7. Stochastic analysis of self-induced vibrations

    DEFF Research Database (Denmark)

    Rüdinger, Finn; Krenk, Steen

    2002-01-01

    Vortex-induced vibrations of a structurl element are modelled as a non-linear stochastic single-degree-of-freedom system. The deterministic part of the governing equation represents laminar flow conditions with a stationary non-zero solution corresponding to lock-in. Across-wind turbulence...

  8. Numerical modelling of rubber vibration isolators

    NARCIS (Netherlands)

    Beijers, C.A.J.; de Boer, Andries; Nilsson, A.; Boden, H.

    2003-01-01

    An important cause for interior noise in vehicles is structure-borne sound from the engine. The vibrations of the source (engine) are transmitted to the receiver structure (the vehicle) causing interior noise in the vehicle. For this reason the engine is supported by rubber isolators for passive

  9. Molecular structure, vibrational spectroscopic studies and natural ...

    Indian Academy of Sciences (India)

    pp. 845–860. Molecular structure, vibrational spectroscopic studies and natural bond orbital analysis of 7-amino-4-trifluoromethyl coumarin ..... [15] A Frisch, A B Nielsen and A J Holder, GAUSSIANVIEW Users Manual, Gaussian. Inc., Pittsburgh, PA (2000). [16] S Selladurai and K Subramanian, Acta Crystallogr. C48, 281 ...

  10. Forced Vibrations of a Cantilever Beam

    Science.gov (United States)

    Repetto, C. E.; Roatta, A.; Welti, R. J.

    2012-01-01

    The theoretical and experimental solutions for vibrations of a vertical-oriented, prismatic, thin cantilever beam are studied. The beam orientation is "downwards", i.e. the clamped end is above the free end, and it is subjected to a transverse movement at a selected frequency. Both the behaviour of the device driver and the beam's weak-damping…

  11. Geometry optimization and vibrational frequencies of tetracene ...

    African Journals Online (AJOL)

    Tetracene is an organic semiconductor with chemical formula C18H12 used in organic field effecttransistor (OFET) and organic light emitting diode (OLED). In this work, the molecular geometry (optimized bond lengths and bond angles), vibrational frequencies and intensities, HOMO-LUMO Energy gap and Atomic charge ...

  12. Animal communication: he's giving me good vibrations.

    Science.gov (United States)

    Hill, Peggy S M

    2015-11-02

    A unique bioassay allows a substrate-borne vibration signal to be isolated and manipulated to test its role in eliciting female mate choice, which may be driving a speciation event, by a live, unrestrained male. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. week whole-body vibration training

    African Journals Online (AJOL)

    The results in this study therefore indicate that WBVT could be used as an ffective training modality to improve cardiovascular function in adult males. As such, WBVT is recommended for use in sedentary adults given its benefits. Keywords: Whole-body vibration training, heart rate, blood pressure, cardiovascular responses.

  14. Vibration isolation techniques suitable for portable electronic speckle pattern interferometry

    Science.gov (United States)

    Findeis, Dirk M.; Gryzagoridis, Jasson; Rowland, David R.

    2002-06-01

    Electronic Speckle Pattern Interferometry (ESPI) and Digital Shearography are optical interference techniques, suitable for non-destructive inspection procedures. Due to the stringent vibration isolation conditions required for ESPI, the technique is mainly suited for laboratory based inspection procedures, which cannot be said for Digital Shearography. On the other hand, the interference patterns obtained using ESPI exhibit better fringe definition and contrast than those obtained using Digital Shearography. The image quality of Digital Shearography can be improved by introducing phase stepping and unwrapping techniques, but these methods add a level of complexity to the inspection system and reduce the image refresh rate of the overall process. As part of a project to produce a low cost portable ESPI system suitable for industrial applications, this paper investigates various methods of minimizing the impact of environmental vibration on the ESPI technique. This can be achieved by effectively 'freezing' the object movement during the image acquisition process. The methods employed include using a high-powered infra-red laser, which is continuously pulsed using an electronic signal generator as well as a mechanical chopper. The effect of using a variable shutter speed camera in conjunction with custom written software acquisition routines is also studied. The techniques employed are described and are applied to selected samples. The initial results are presented and analyzed. Conclusions are drawn and their impact on the feasibility of a portable ESPI system discussed.

  15. Optical vibration detection spectral analysis assembly and method for detecting vibration in an object of interest

    Science.gov (United States)

    Hale, Thomas C.; Telschow, Kenneth L.

    1998-01-01

    A vibration detection assembly is described which includes an emitter of light which has object and reference beams, the object beam reflected off of a vibrating object of interest; and a photorefractive substance having a given response time and which passes the reflected object beam and the reference beam, the reference beam and the object beam interfering within the photorefractive substance to create a space charge field which develops within the response time of the photorefractive substance.

  16. Downhole Vibration Monitoring and Control System

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2007-09-30

    The objective of this program is to develop a system to both monitor the vibration of a bottomhole assembly, and to adjust the properties of an active damper in response to these measured vibrations. The key feature of this system is its use of a magnetorheological fluid (MRF) to allow the damping coefficient to be changed extensively, rapidly and reversibly without the use of mechanical valves, but only by the application of a current. Phase I of this program, which entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype, was completed on May 31, 2004. Much of the effort was devoted to the design and testing of the MRF damper, itself. The principal objectives of Phase II were: more extensive laboratory testing, including the evaluation of different feedback algorithms for control of the damper; design and manufacture of a field prototype system; and, testing of the field prototype in a drilling laboratory. Phase II concluded on January 31, 2006, and a final report was issued. Work on Phase III of the project began during the first quarter, 2006, with the objectives of building precommercial prototypes, testing them in a drilling laboratory and the field; developing and implementing a commercialization plan. All of these have been accomplished. The Downhole Vibration Monitoring & Control System (DVMCS) prototypes have been successfully proven in testing at the TerraTek drilling facility and at the Rocky Mountain Oilfield Test Center (RMOTC.) Based on the results of these tests, we have signed a definitive development and distribution agreement with Smith, and commercial deployment is underway. This current version of the DVMCS monitors and controls axial vibrations. Due to time and budget constraints of this program, it was not possible to complete a system that would also deal with lateral and torsional (stick-slip) vibrations as originally planned; however, this effort is continuing without DOE

  17. Vibration Analysis of a Residential Building

    Directory of Open Access Journals (Sweden)

    Sampaio Regina Augusta

    2015-01-01

    Full Text Available The aim of this paper is to present the results of a study regarding vibration problems in a 17 storey residential building during pile driving in its vicinity. The structural design of the building was checked according to the Brazilian standards NBR6118 and NBR6123, and using commercial finite element software. An experimental analysis was also carried out using low frequency piezo-accelerometers attached to the building structure. Structure vibrations were recorded under ambient conditions. Four monitoring tests were performed on different days. The objective of the first monitoring test was an experimental modal analysis. To obtain de modal parameters, data was processed in the commercial software ARTEMIS employing two methods: the Stochastic Subspace Identification and the Frequency Domain Decomposition. Human comfort was investigated considering the International Standard ISO 2631. The Portuguese standard, NP2074, was also used as a reference, since it aims to limit the adverse effects of vibrations in structures caused by pile driving in the vicinity of the structure. The carried out experimental tests have shown that, according to ISO2301, the measure vibration levels are above the acceptance limits. However, velocity peaks are below the limits established by NP2074. It was concluded that, although the structure has adequate capacity to resist internal forces according to normative criteria, it has low horizontal stiffness, which could be verified by observing the vibration frequencies and mode shapes obtained with the finite element models, and its similarity with the experimental results. Thus, the analyses indicate the occurrence of discomfort by the residents.

  18. Modeling Vibration Intensity of Aircraft Bevel Gears

    Directory of Open Access Journals (Sweden)

    V. V. Golovanov

    2017-01-01

    Full Text Available The subject is the aircraft bevel gears, which are part of the drive systems of gas turbine engines and helicopter transmissions. The article deals with defect specifics of the aircraft conical gears with a circular tooth as compared to the conical gear wheels of general engineering. The finite element method has been used to find by calculation that the main reason for destruction of aircraft bevel gears is a resonant vibration excitation of the gear wheel rim due to its nodal diameter eigenvibrations happened to be within the operating range of the transmission rotation frequencies. A parametric finite element model has been developed. It allows us to investigate the impact of modification parameters of the drive side of gear wheels on the function of the kinematic transmission error at different values of transmitted torque. Using the method of main coordinates, a reduced dynamic model of the bevel gear has been developed to allow simulating the vibration intensity of bevel gears with various parameters of the working profile modification. Within the framework of evaluation test of the dynamic model, amplitude-frequency characteristics have been constructed for the main parameters of transmission oscillations, including vibrational stresses in the teeth space. It is found that modification parameters of the transmission drive side have a significant effect on the vibration intensity of the bevel gears in the entire operating range. The main factor affecting the vibration stress amplitude in the gear wheel is the amplitude of the kinematic error function with the corresponding torque transmitted. The obtained research results can be used when designing the new aircraft drives and modernizing the existing ones. As part of the further development, it is expected to create a technique for recording the damage accumulation in the conical gears, taking into account the typical flight profile of a gas turbine engine or a helicopter.

  19. Metrology of vibration measurements by laser techniques

    Science.gov (United States)

    von Martens, Hans-Jürgen

    2008-06-01

    Metrology as the art of careful measurement has been understood as uniform methodology for measurements in natural sciences, covering methods for the consistent assessment of experimental data and a corpus of rules regulating application in technology and in trade and industry. The knowledge, methods and tools available for precision measurements can be exploited for measurements at any level of uncertainty in any field of science and technology. A metrological approach to the preparation, execution and evaluation (including expression of uncertainty) of measurements of translational and rotational motion quantities using laser interferometer methods and techniques will be presented. The realization and dissemination of the SI units of motion quantities (vibration and shock) have been based on laser interferometer methods specified in international documentary standards. New and upgraded ISO standards are reviewed with respect to their suitability for ensuring traceable vibration measurements and calibrations in an extended frequency range of 0.4 Hz to higher than 100 kHz. Using adequate vibration exciters to generate sufficient displacement or velocity amplitudes, the upper frequency limits of the laser interferometer methods specified in ISO 16063-11 for frequencies <= 10 kHz can be expanded to 100 kHz and beyond. A comparison of different methods simultaneously used for vibration measurements at 100 kHz will be demonstrated. A statistical analysis of numerous experimental results proves the highest accuracy achievable currently in vibration measurements by specific laser methods, techniques and procedures (i.e. measurement uncertainty 0.05 % at frequencies <= 10 kHz, <= 1 % up to 100 kHz).

  20. Relating normal vibrational modes to local vibrational modes: benzene and naphthalene.

    Science.gov (United States)

    Zou, Wenli; Kalescky, Robert; Kraka, Elfi; Cremer, Dieter

    2013-07-01

    Local vibrational modes can be directly derived from normal vibrational modes using the method of Konkoli and Cremer (Int J Quant Chem 67:29, 1998). This implies the calculation of the harmonic force constant matrix F (q) (expressed in internal coordinates q) from the corresponding Cartesian force constant matrix f (x) with the help of the transformation matrix U = WB (†)(BWB (†))(-1) (B: Wilson's B-matrix). It is proven that the local vibrational modes are independent of the choice of the matrix W. However, the choice W = M (-1) (M: mass matrix) has numerical advantages with regard to the choice W = I (I: identity matrix), where the latter is frequently used in spectroscopy. The local vibrational modes can be related to the normal vibrational modes in the form of an adiabatic connection scheme (ACS) after rewriting the Wilson equation with the help of the compliance matrix. The ACSs of benzene and naphthalene based on experimental vibrational frequencies are discussed as nontrivial examples. It is demonstrated that the local-mode stretching force constants provide a quantitative measure for the C-H and C-C bond strength.

  1. Transient vibration analytical modeling and suppressing for vibration absorber system under impulse excitation

    Science.gov (United States)

    Wang, Xi; Yang, Bintang; Yu, Hu; Gao, Yulong

    2017-04-01

    The impulse excitation of mechanism causes transient vibration. In order to achieve adaptive transient vibration control, a method which can exactly model the response need to be proposed. This paper presents an analytical model to obtain the response of the primary system attached with dynamic vibration absorber (DVA) under impulse excitation. The impulse excitation which can be divided into single-impulse excitation and multi-impulse excitation is simplified as sinusoidal wave to establish the analytical model. To decouple the differential governing equations, a transform matrix is applied to convert the response from the physical coordinate to model coordinate. Therefore, the analytical response in the physical coordinate can be obtained by inverse transformation. The numerical Runge-Kutta method and experimental tests have demonstrated the effectiveness of the analytical model proposed. The wavelet of the response indicates that the transient vibration consists of components with multiple frequencies, and it shows that the modeling results coincide with the experiments. The optimizing simulations based on genetic algorithm and experimental tests demonstrate that the transient vibration of the primary system can be decreased by changing the stiffness of the DVA. The results presented in this paper are the foundations for us to develop the adaptive transient vibration absorber in the future.

  2. Piezoelectric nonlinear vibration focusing on the second-harmonic vibration mode.

    Science.gov (United States)

    Ozaki, Ryohei; Liu, Yaoyang; Hosaka, Hiroshi; Morita, Takeshi

    2018-01-01

    Resonant piezoelectric devices are driven under high power condition. In such condition, a nonlinear piezoelectric vibration becomes apparent and this nonlinearity should be taken into account in the design procedure using the finite elemental method (FEM). The purpose of this study is to introduce the nonlinear parameter to the FEM and to establish the method for measuring the nonlinear parameter through evaluating a nonlinear model for a piezoelectric vibration. In a previous study about the nonlinear piezoelectric vibration, the third term was mainly focused on because the third mode vibration affects the fundamental vibration in the case of a simple bar-type transducer. On the other hand, we considered the second nonlinear parameter of the compliance to the piezoelectric constitutive equation. We observed that this parameter affects the vibration amplitude with each position and the velocity at the tip of the transducer with a double frequency at resonant. It was confirmed that two measured nonlinear parameters based on these two relationships were almost same. From these values, we concluded that the proposed model is reasonable. Copyright © 2017. Published by Elsevier B.V.

  3. Development of S-wave portable vibrator; S ha potable vibrator shingen no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kaida, Y.; Matsubara, Y. [OYO Corp., Tokyo (Japan); Nijhof, V.; Brouwer, J.

    1996-05-01

    An S-wave portable vibrator to serve as a seismic source has been developed for the purpose of applying the shallow-layer reflection method to the study of the soil ground. The author, et al., who previously developed a P-wave portable vibrator has now developed an S-wave version, considering the advantage of the S-wave over the P-wave in that, for example, the S-wave velocity may be directly compared with the N-value representing ground strength and that the S-wave travels more slowly than the P-wave through sticky soil promising a higher-resolution exploration. The experimentally constructed S-wave vibrator consists of a conventional P-wave vibrator and an L-type wooden base plate combined therewith. Serving as the monitor for vibration is a conventional accelerometer without any modification. The applicability test was carried out at a location where a plank hammering test was once conducted for reflection aided exploration, and the result was compared with that of the plank hammering test. As the result, it was found that after some preliminary treatment the results of the two tests were roughly the same but that both reflected waves were a little sharper in the S-wave vibrator test than in the plank hammering test. 4 refs., 9 figs., 1 tab.

  4. Vibration transfers to measure the performance of vibration isolated platforms on site using background noise excitation

    Science.gov (United States)

    Segerink, F. B.; Korterik, J. P.; Offerhaus, H. L.

    2011-06-01

    This article demonstrates a quick and easy way of quantifying the performance of a vibration-isolated platform. We measure the vibration transfer from floor to table using background noise excitation from the floor. As no excitation device is needed, our setup only requires two identical sensors (in our case, low noise accelerometers), a data acquisition system, and processing software. Background noise excitation from the floor has the additional advantage that any non-linearity in the suspension system relevant to the actual vibration amplitudes will be taken into account. Measurement time is typically a few minutes, depending on the amount of background noise. The (coherent) transfer of the vibrations in the floor to the platform, as well as the (non-coherent) acoustical noise pick-up by the platform are measured. Since we use calibrated sensors, the absolute value of the vibration levels is established and can be expressed in vibration criterion curves. Transfer measurements are shown and discussed for two pneumatic isolated optical tables, a spring suspension system, and a simple foam suspension system.

  5. Low-frequency vibration control of floating slab tracks using dynamic vibration absorbers

    Science.gov (United States)

    Zhu, Shengyang; Yang, Jizhong; Yan, Hua; Zhang, Longqing; Cai, Chengbiao

    2015-09-01

    This study aims to effectively and robustly suppress the low-frequency vibrations of floating slab tracks (FSTs) using dynamic vibration absorbers (DVAs). First, the optimal locations where the DVAs are attached are determined by modal analysis with a finite element model of the FST. Further, by identifying the equivalent mass of the concerned modes, the optimal stiffness and damping coefficient of each DVA are obtained to minimise the resonant vibration amplitudes based on fixed-point theory. Finally, a three-dimensional coupled dynamic model of a metro vehicle and the FST with the DVAs is developed based on the nonlinear Hertzian contact theory and the modified Kalker linear creep theory. The track irregularities are included and generated by means of a time-frequency transformation technique. The effect of the DVAs on the vibration absorption of the FST subjected to the vehicle dynamic loads is evaluated with the help of the insertion loss in one-third octave frequency bands. The sensitivities of the mass ratio of DVAs and the damping ratio of steel-springs under the floating slab are discussed as well, which provided engineers with the DVA's adjustable room for vibration mitigation. The numerical results show that the proposed DVAs could effectively suppress low-frequency vibrations of the FST when tuned correctly and attached properly. The insertion loss due to the attachment of DVAs increases as the mass ratio increases, whereas it decreases with the increase in the damping ratio of steel-springs.

  6. The influence of flywheel micro vibration on space camera and vibration suppression

    Science.gov (United States)

    Li, Lin; Tan, Luyang; Kong, Lin; Wang, Dong; Yang, Hongbo

    2018-02-01

    Studied the impact of flywheel micro vibration on a high resolution optical satellite that space-borne integrated. By testing the flywheel micro vibration with six-component test bench, the flywheel disturbance data is acquired. The finite element model of the satellite was established and the unit force/torque were applied at the flywheel mounting position to obtain the micro vibration data of the camera. Integrated analysis of the data of the two parts showed that the influence of flywheel micro vibration on the camera is mainly concentrated around 60-80 Hz and 170-230 Hz, the largest angular displacement of the secondary mirror along the optical axis direction is 0.04″ and the maximum angular displacement vertical to optical axis is 0.032″. After the design and installation of vibration isolator, the maximum angular displacement of the secondary mirror is 0.011″, the decay rate of root mean square value of the angular displacement is more than 50% and the maximum is 96.78%. The whole satellite was suspended to simulate the boundary condition on orbit; the imaging experiment results show that the image motion caused by the flywheel micro vibrationis less than 0.1 pixel after installing the vibration isolator.

  7. Based On Intrinsic Mode Function Energy Tracking Method of Circuit Breaker Vibration Signal Feature Extraction Studies

    Directory of Open Access Journals (Sweden)

    Sun Yi-Hang

    2017-01-01

    Full Text Available In order to detect a mechanical type of structural failure of the circuit breaker, the characteristics of the circuit breaker mechanical vibration signal is analyzed in this paper. A combination of medium voltage circuit breaker based on empirical mode decomposition (EMD amount of energy and support vector machine (SVM theory vibration signal feature vector extraction and analysis of fault classification method is proposed. First, the vibration signal of the circuit breaker is decomposed by EMD, then intrinsic mode function (IMF is obtain. The major fault feature information intrinsic mode functions the amount of energy of the component is obtained by discrete sampling points and the amount of energy. Using the amount of energy of IMF component as a feature vector, the failure of the test sample signal as input feature vector into trained “BT-SVM” support vector machine classification mechanism for fault classification. The differences and fault type of vibration signals can be identified by this method through the experimental analysis.

  8. Changes in a woman's sexual experience and expectations following the introduction of electric vibrator assistance.

    Science.gov (United States)

    Marcus, Bat Sheva

    2011-12-01

    This study explores how a woman's sexual expectations and experiences change when she introduces an electrical vibrator into her sexual activity. Examine participants' behavioral changes and changes in attitude and expectations after introducing a vibrator. Seventeen heterosexual women, ages 23-55, who had never used a vibrator, used one at least once a week for 1 month and then participated in interviews about their experiences. The "grounded theory method," provided qualitative data from the interview transcripts. Repeating ideas and themes were extracted and coded from all interviews. The researcher assessed whether the initial sample size was large enough to provide "saturation" (that is, did it appear that the same themes kept emerging) and continued interviewing until such a sample was determined. Six recurring concerns emerged: (i) change in orgasmic patterns; (ii) fear of using an outside, "unnatural" object; (iii) dependency; (iv) entitlement; (v) reaction of partners; and (vi) changes in sexual attitudes. Clinicians recommending vibrator use to women, whether because of anorgasmia, female sexual arousal disorder, or any other sexual problems, should prepare their patients for changes in these areas. © 2010 International Society for Sexual Medicine.

  9. Elevating sampling

    Science.gov (United States)

    Labuz, Joseph M.; Takayama, Shuichi

    2014-01-01

    Sampling – the process of collecting, preparing, and introducing an appropriate volume element (voxel) into a system – is often under appreciated and pushed behind the scenes in lab-on-a-chip research. What often stands in the way between proof-of-principle demonstrations of potentially exciting technology and its broader dissemination and actual use, however, is the effectiveness of sample collection and preparation. The power of micro- and nanofluidics to improve reactions, sensing, separation, and cell culture cannot be accessed if sampling is not equally efficient and reliable. This perspective will highlight recent successes as well as assess current challenges and opportunities in this area. PMID:24781100

  10. Behavior of granite-epoxy composite beams subjected to mechanical vibrations

    Directory of Open Access Journals (Sweden)

    Antonio Piratelli-Filho

    2010-12-01

    Full Text Available The capacity to damp mechanical vibrations is one of the most important properties of granite-epoxy composites, even superior to the cast iron one. For this reason, these materials have been adopted for manufacturing of tool machine foundations and precision instruments. This work presents a study concerning the behavior of particulate composite beams, based on granite powder and epoxy, subjected to mechanical vibrations. Composite samples were prepared with different combinations of processing variables, like the weight fraction of epoxy in the mixture and size distributions of granite particles. The damping behavior of the material was investigated adopting the logarithmic decrement method. Samples, in the form of prismatic beams, were excited in the middle point and the output signal was measured in a point located at the extremity. The obtained results showed that composite samples, with weight fractions of about 80% of granite and 20% of epoxy, presented damping properties approximately three times greater than gray cast iron.

  11. Quality Factor and Microslipping of Fatigue Cracks in Thin Plates at Resonant Vibration

    Science.gov (United States)

    Wincheski, B.; Namkung, M.; Fulton, J. P.

    1993-01-01

    Resonant vibrations have been stimulated in thin metal plates using a non-contacting electromagnetic driver. A sinusoidal force was applied in a swept frequency fashion and the resulting surface displacements were monitored through the use of an acoustic microphone. It has been found that the presence of a fatigue crack in the sample causes a broadening of the second resonance peak. The Q factors of the resonance curves were determined and are directly correlated with the presence of fatigue cracks in the samples. The broadening of the curves is explained in terms of a microslipping at the crack face walls which reduces the amplitude of the resonant vibration by increasing the damping of the system. A comparison is made between the resonance characteristics of fatigue damaged and notched samples, where the stiffness of the two systems is nearly constant while the interaction between crack face walls is eliminated in the latter.

  12. VIBRATION SENSORS AND MICROELECTROMECHANICAL SYSTEM FOR MOBILE DEVICES SUCH AS ANALOGS, FOR EVALUATION OF VIBRATION OF ROTARY MACHINES

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available The paper carried out a comparison of vibration sensors used to measure the vibration condition units with gas turbine engines, with motion sensors, microelectromechanical systems used in modern mobile devices (for example, devices on the platform "Android". It provides opinions on the possibility of assessment of vibration, using sensors of mobile devices.

  13. The effect of the training with the different combinations of frequency and peak-to-peak vibration displacement of whole-body vibration on the strength of knee flexors and extensors

    Directory of Open Access Journals (Sweden)

    M Stania

    2017-01-01

    Full Text Available Whole-body vibration training has become a popular method used in sports and physiotherapy. The study aimed to evaluate the effect of different vibration frequency and peak-to-peak displacement combinations on men knee flexors and extensors strength in isokinetic conditions. The sample consisted of 49 male subjects randomly allocated to seven comparative groups, six of which exercised on a vibration platform with parameters set individually for the groups. The experimental groups were exposed to vibrations 3 times a week for 4 weeks. The pre- and post- isokinetic strength tests, with the angular velocities of 240°/s and 30°/s, were recorded prior to and 2 days after the training. After 4 weeks of whole-body vibration training, a significant increase was noted regarding the mean values of peak torque, average peak torque and total work for knee flexors at high angular velocity in Groups I (60 Hz/ 4 mm and V (40 Hz/ 2 mm (p<0.05. The mean percentage values of post-training changes to study parameters suggest that the training had the most beneficial effect in Groups I (60 Hz/4 mm and IV (60 Hz/2 mm (p<0.05. Whole-body vibrations during static exercise beneficially affected knee flexor strength profile in young men at high angular velocity. The combinations of 60 Hz/4 mm seem to have the most advantageous effects on muscle strength parameters.

  14. Verification of the Microgravity Active Vibration Isolation System based on Parabolic Flight

    Science.gov (United States)

    Zhang, Yong-kang; Dong, Wen-bo; Liu, Wei; Li, Zong-feng; Lv, Shi-meng; Sang, Xiao-ru; Yang, Yang

    2017-12-01

    The Microgravity active vibration isolation system (MAIS) is a device to reduce on-orbit vibration and to provide a lower gravity level for certain scientific experiments. MAIS system is made up of a stator and a floater, the stator is fixed on the spacecraft, and the floater is suspended by electromagnetic force so as to reduce the vibration from the stator. The system has 3 position sensors, 3 accelerometers, 8 Lorentz actuators, signal processing circuits and a central controller embedded in the operating software and control algorithms. For the experiments on parabolic flights, a laptop is added to MAIS for monitoring and operation, and a power module is for electric power converting. The principle of MAIS is as follows: the system samples the vibration acceleration of the floater from accelerometers, measures the displacement between stator and floater from position sensitive detectors, and computes Lorentz force current for each actuator so as to eliminate the vibration of the scientific payload, and meanwhile to avoid crashing between the stator and the floater. This is a motion control technic in 6 degrees of freedom (6-DOF) and its function could only be verified in a microgravity environment. Thanks for DLR and Novespace, we get a chance to take the DLR 27th parabolic flight campaign to make experiments to verify the 6-DOF control technic. The experiment results validate that the 6-DOF motion control technique is effective, and vibration isolation performance perfectly matches what we expected based on theoretical analysis and simulation. The MAIS has been planned on Chinese manned spacecraft for many microgravity scientific experiments, and the verification on parabolic flights is very important for its following mission. Additionally, we also test some additional function by microgravity electromagnetic suspension, such as automatic catching and locking and working in fault mode. The parabolic flight produces much useful data for these experiments.

  15. Verification of the Microgravity Active Vibration Isolation System based on Parabolic Flight

    Science.gov (United States)

    Zhang, Yong-kang; Dong, Wen-bo; Liu, Wei; Li, Zong-feng; Lv, Shi-meng; Sang, Xiao-ru; Yang, Yang

    2017-09-01

    The Microgravity active vibration isolation system (MAIS) is a device to reduce on-orbit vibration and to provide a lower gravity level for certain scientific experiments. MAIS system is made up of a stator and a floater, the stator is fixed on the spacecraft, and the floater is suspended by electromagnetic force so as to reduce the vibration from the stator. The system has 3 position sensors, 3 accelerometers, 8 Lorentz actuators, signal processing circuits and a central controller embedded in the operating software and control algorithms. For the experiments on parabolic flights, a laptop is added to MAIS for monitoring and operation, and a power module is for electric power converting. The principle of MAIS is as follows: the system samples the vibration acceleration of the floater from accelerometers, measures the displacement between stator and floater from position sensitive detectors, and computes Lorentz force current for each actuator so as to eliminate the vibration of the scientific payload, and meanwhile to avoid crashing between the stator and the floater. This is a motion control technic in 6 degrees of freedom (6-DOF) and its function could only be verified in a microgravity environment. Thanks for DLR and Novespace, we get a chance to take the DLR 27th parabolic flight campaign to make experiments to verify the 6-DOF control technic. The experiment results validate that the 6-DOF motion control technique is effective, and vibration isolation performance perfectly matches what we expected based on theoretical analysis and simulation. The MAIS has been planned on Chinese manned spacecraft for many microgravity scientific experiments, and the verification on parabolic flights is very important for its following mission. Additionally, we also test some additional function by microgravity electromagnetic suspension, such as automatic catching and locking and working in fault mode. The parabolic flight produces much useful data for these experiments.

  16. DFT study of the molecular and crystal structure and vibrational analysis of cisplatin

    Science.gov (United States)

    Georgieva, I.; Trendafilova, N.; Dodoff, N.; Kovacheva, D.

    2017-04-01

    DFT and periodic-DFT (PAW-PBE method, code VASP) calculations have been performed to study the structural and vibrational characteristics of cis-diamminedichloroplatinum(II) (cisplatin) at molecular and outside molecular level. To estimate the effect of the intermolecular interactions in crystal on the structural and vibrational properties of cisplatin, three theoretical models are considered in the present study: monomer (isolated molecule), hydrogen bonded dimer and periodic solid state structures. The work focused on the role of the theoretical models for correct modeling and prediction of geometrical and vibrational parameters of cisplatin. It has been found that the elaborate three-dimensional intermolecular hydrogen bonding network in the crystalline cisplatin significantly influences the structural and vibrational pattern of cisplatin and therefore the isolated cisplatin molecule is not the correct computational model regardless of the theoretical level used. To account for the whole intermolecular hydrogen bonding network in direction of both a and c axis and for more reliable calculations of structural and vibrational parameters periodic DFT calculations were carried out in the full crystalline periodic environment with the known lattice parameters for each cisplatin polymorph phase. The model calculations performed both at molecular level and for the periodic structures of alpha and beta cisplatin polymorph forms revealed the decisive role of the extended theoretical model for reliable prediction of the structural and vibrational characteristics of cisplatin. The powder diffraction pattern and the calculated IR and Raman spectra predicted beta polymorph form of our cisplatin sample freshly synthesized for the purposes of the present study using the Dhara's method. The various rotamers realized in the polymorph forms of cisplatin were explained by the low population of the large number of rotamers in solution as well as with the high rotamer

  17. Chest vibration redistributes intra-airway CO2 during tracheal insufflation in ventilatory failure.

    Science.gov (United States)

    Eckmann, D M; Gavriely, N

    1996-03-01

    To determine if high-frequency external chest wall vibration added to low flow intratracheal fresh gas insufflation alters the intra-airway CO2 distribution and the resistance to CO2 transport from the lungs. Prospective study. Experimental laboratory. Six adult anesthesized and paralyzed mongrel dogs (mean weight 24.3+/- 4.4 kg). Dogs were ventilated by three methods: a) intermittent positive pressure ventilation; b) intermittent positive pressure ventilation with tracheal insufflation of fresh gas (FIO2 of 0.4) flowing at 0.15 L/kg/min through a catheter positioned at the carina; and c) intermittent positive pressure ventilation with tracheal insufflation and with external high-frequency chest wall vibration of the dependent hemithorax. We measured arterial blood gas values as an index of global gas exchange, and intrapulmonary airway CO2 concentrations as an index of local gas exchange. Intra-airway CO2 concentrations along the axis of the airways were measured via a sampling catheter. Airway axial concentration profiles were constructed and resistances to gas transport were calculated from the measured data. Vibration increased intraluminal CO2 concentrations from 1.1% to 2.5% mouthward of the insufflation catheter tip. Peak resistance to CO2 transport decreased by 65% during vibration relative to the insufflation-only value. Vibration displaced peak transport resistance from second- to fourth-generation airways. Global gas exchange improves during ventilation by chest wall vibration with low flow insufflation. Local gas exchange in the central airways is also improved due to increased intraluminal mixing and CO2 elimination. This ventilation technique may confer therapeutic advantages over conventional mechanical ventilation in the treatment of ventilatory failure.

  18. Analysis of different vibration patterns to guide blind people

    Directory of Open Access Journals (Sweden)

    Juan V. Durá-Gil

    2017-03-01

    Full Text Available The literature indicates the best vibration positions and frequencies on the human body where tactile information is transmitted. However, there is a lack of knowledge about how to combine tactile stimuli for navigation. The aim of this study is to compare different vibration patterns outputted to blind people and to determine the most intuitive vibration patterns to indicate direction for navigation purposes through a tactile belt. The vibration patterns that stimulate the front side of the waist are preferred for indicating direction. Vibration patterns applied on the back side of the waist could be suitable for sending messages such as stop.

  19. The photodissociation and reaction dynamics of vibrationally excited molecules

    Energy Technology Data Exchange (ETDEWEB)

    Crim, F.F. [Univ. of Wisconsin, Madison (United States)

    1993-12-01

    This research determines the nature of highly vibrationally excited molecules, their unimolecular reactions, and their photodissociation dynamics. The goal is to characterize vibrationally excited molecules and to exploit that understanding to discover and control their chemical pathways. Most recently the author has used a combination of vibrational overtone excitation and laser induced fluorescence both to characterize vibrationally excited molecules and to study their photodissociation dynamics. The author has also begun laser induced grating spectroscopy experiments designed to obtain the electronic absorption spectra of highly vibrationally excited molecules.

  20. FEM Updating of Tall Buildings using Ambient Vibration Data

    DEFF Research Database (Denmark)

    Ventura, C. E.; Lord, J. F.; Turek, M.

    2005-01-01

    Ambient vibration testing is the most economical non-destructive testing method to acquire vibration data from large civil engineering structures. The purpose of this paper is to demonstrate how ambient vibration Modal Identification techniques can be effectively used with Model Updating tools...... and the corresponding mode shapes. The degree of torsional coupling between the modes was also investigated. The modal identification results obtained from ambient vibration measurements of each building were used to update a finite element model of the structure. The starting model of each structure was developed from...... an ambient vibration modal identification....