TITLE

An impedance-measurement setup optimized for measuring relaxations of glass-forming liquids

AUTHOR(S)
Igarashi, Brian; Christensen, Tage; Larsen, Ebbe H.; Olsen, Niels Boye; Pedersen, Ib H.; Rasmussen, Torben; Dyre, Jeppe C.
PUB. DATE
April 2008
SOURCE
Review of Scientific Instruments;Apr2008, Vol. 79 Issue 4, p045106
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
An electronics system has been assembled to measure frequency-dependent response functions of glass-forming liquids in the extremely viscous state approaching the glass transition. We determine response functions such as dielectric permittivity and shear and bulk moduli by measuring electrical impedances of liquid-filled transducers, and this technique requires frequency generators capable of producing signals that are reproducible over the span of several days or even several weeks. To this end, we have constructed a frequency generator that produces low-frequency (1 mHz–100 Hz) sinusoidal signals with voltages that are reproducible within 10 ppm. Two factors that partly account for this precision are that signals originate from voltages stored in a look-up table and that only coil-less filters are used in this unit, which significantly reduces fluctuations of output caused by changes of temperatures of circuits. This generator also includes a special triggering facility that makes it possible to measure up to 512 voltages per cycle that are spaced apart at uniform phase intervals. Fourier transformations of such data yield precise determinations of complex amplitudes of voltages and currents applied to a transducer, which ultimately allows us to determine electrical impedances of transducers with a reproducibility error that is only a few parts per hundred thousand. This equipment is used in tandem with a commercial LCR meter and/or impedance analyzer that give(s) impedance measurements at higher frequencies, up to 1 MHz. The experimental setup allows measurements of the transducer impedance over nine decades of frequency within a single run.
ACCESSION #
31938721

 

Related Articles

  • Condition Based Monitoring and Diagnosis of Rotating Electrical Machines Bearings Using FFT and Wavelet Analysis. COZORICI, Ioan; VĂ DAN, Ioan; BALAN, Horia // Acta Electrotehnica;2012, Vol. 53 Issue 4, p350 

    Condition Based Monitoring of rotating electrical machines is usually based on vibration signal analysis. In the presence of a mechanical or electrical failure, vibration signals contain periodic pulses with a characteristic frequency corresponding to a certain fault. However, due to higher...

  • Fourier Transformation Analysis in Capillary Flow—A New Option to Detect Flow Instabilities (Shark Skin). Göttfert, A.; Sunder, J. // AIP Conference Proceedings;7/7/2008, Vol. 1027 Issue 1, p1195 

    Flow instabilities cause various problems in extrusion, coating, calandering and blow- or flat film processes. Especially shark skin is affected by the molecular structure and additives. This phenomenon is analyzed in various scientific works using apparatus that are complex or difficult in...

  • Coating thickness and elastic modulus measurement using ultrasonic bulk wave resonance. Dixon, S.; Lanyon, B.; Rowlands, G. // Applied Physics Letters;4/3/2006, Vol. 88 Issue 14, p141907 

    Measurement of the resonant through thickness ultrasonic modes of a homogeneous plate using a fast Fourier transform of the temporal data can be used to calculate plate thickness very accurately. We describe an extension of this principle to two-layer systems, examining a thin coating on a...

  • Application of Fourier harmonic analysis to the electromechanical response of an electroactive material. DiAntonio, C. B.; Williams, F. A.; Pilgrim, S. M.; Schulze, W. A. // Journal of Applied Physics;10/1/2002, Vol. 92 Issue 7, p3908 

    Signal decomposition through Fourier analysis can aid quantification of the electromechanical properties (induced strain and polarization) of electroactive materials. Spectral analysis of the strain and polarization, obtained from the Fourier transform, provides a unique characterization tool...

  • 3-D Flaw Imaging by Inverse Scattering Analysis Using Ultrasonic Array Transducer. Nakahata, K.; Saitoh, T.; Hirose, S. // AIP Conference Proceedings;2007, Vol. 894 Issue 1, p717 

    Ultrasonic matrix array transducers have the advantage of receiving flaw echoes simultaneously at various points on a flat surface of the test material. Here we propose 3-D imaging techniques to reconstruct flaw shapes with the array transducer. These techniques are based on linearized inverse...

  • Cable position and velocity transducer.  // Machine Design;1/25/2001, Vol. 73 Issue 2, pS118 

    Evaluates the Cable Sensor CS2 Series cable position and velocity transducer from Synnate Controls.

  • Buyer's Index.  // American City & County;Apr2004, Vol. 119 Issue 4, p56 

    Evaluates several electromechanical devices. Series 340 transducer for waterworks from Pressure Systems; Quadblaster QB-4 bird repellant from Bird-X; McL-36/42HD auger boring machine for public works from McLaughlin Group.

  • Very compact ortho-mode transducers with double septum configuration. Ruiz-Cruz, Jorge A.; Montejo-Garai, Jos´ R.; Rebollar, Jesús M.; Montesano, Carlos E.; Martín, María J. // Microwave & Optical Technology Letters;Apr2006, Vol. 48 Issue 4, p765 

    This paper describes the analysis and design results of a very compact ortho-mode transducer (OMT) for dual-polarization communication systems. The presented configuration introduces an additional double septum in the conventional structure, not reported previously, which provides a number of...

  • A Spherically Focused Capacitive-Film Air-Coupled Transducer. Junho Song; Holland, Stephen D.; Chimenti, D. E. // AIP Conference Proceedings;2006, Vol. 820 Issue 1, p908 

    We have developed, fabricated, and tested spherically focused capacitive-film air-coupled ultrasonic transducers, which need no mirror, zone plate, or similar external device. To achieve native focusing, we have employed a flexible copper/polyimide backplate that permits a conformal fit to a...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics