A high-frequency piezoelectric rheometer with validation of the loss angle measuring loop: application to polymer melts and colloidal glasses

2019 ◽  
Vol 58 (9) ◽  
pp. 619-637 ◽  
Author(s):  
Thanasis Athanasiou ◽  
Gunter K. Auernhammer ◽  
Dimitris Vlassopoulos ◽  
George Petekidis
Keyword(s):  
High Frequency ◽  
Polymer Melts ◽  
Loss Angle ◽  
Angle Measuring ◽  
Colloidal Glasses

Loss Angle Testing of Polymer Melts at High Shear Rate

2013 ◽  
Vol 389 ◽  
pp. 352-358
Author(s):  
Xiang Gang Li ◽  
Yue Jun Liu ◽  
Yu Gang Huang ◽  
Pu Shi ◽  
Mei Jun Tan
Keyword(s):  
Shear Rate ◽  
Phase Difference ◽  
Polymer Melts ◽  
High Shear Rate ◽  
High Shear ◽  
Loss Angle ◽  
Vibration Displacement ◽  
Viscous Losses ◽  
Dynamic Components ◽  
Intrinsic Vibration

Theoretical and experimental study of loss angle of polymer melts at high shear rate was done based on multi-function and all-electric rheometer (MAR) designed by the authors. The phase difference of the dynamic components of shear strain and shear stress at the capillary wall proved to be as same as the phase difference of superimposed vibration displacement and the entrance pressure. In order to get the loss angle, the intrinsic vibration displacement was defined and original signal was transformed from time domain representation to frequency domain representation by DFT. The experiment results show that the loss angle increases greatly with the increase of the superimposed vibration displacement frequency. It indicates that the viscous losses increase while the elastic properties decrease with the increase of the superimposed vibration displacement frequency. The loss angle didnt change notably with the increase of the piston steady velocity and the superimposed vibration displacement amplitude. This indicates that the viscoelastic properties keep consistence when the shear rate and piston amplitude changes.

An Oscillating Disk Rheometer for Measuring Dynamic Properties during Vulcanization

1963 ◽  
Vol 36 (2) ◽  
pp. 451-458 ◽  
Author(s):  
G. E. Decker ◽  
R. W. Wise ◽  
D. Guerry
Keyword(s):  
Small Angle ◽  
High Frequency ◽  
Unique Feature ◽  
Dynamic Properties ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Stress And Strain ◽  
Loss Angle ◽  
High Frequencies ◽  
Rubber Specimen

Abstract A forced oscillating-disk rheometer has been developed which can measure both the low and high frequency dynamic properties of a rubber specimen throughout vulcanization. It may also be used to measure the rheological properties of unvulcanized polymers. The instrument consists of a cone-shaped disk which is embedded in the rubber specimen and oscillated through a small angle while the specimen is heated under pressure. Both stress and strain in terms of torque and displacement, respectively, are measured by appropriate transducers and recorded on an oscillograph. Provisions are made for changing both frequency and strain. At low frequency, the instrument is a convenient tool for determining all of the curing parameters of a rubber specimen. At high frequencies, the change in the dynamic properties of a rubber specimen throughout vulcanization may be continuously followed. A unique feature of the rheometer is that the loss angle may be determined which permits resolution of the measured dynamic stiffness into its elastic and viscous components.

Inductosyn Angle Measurement Method Based on the Pulse Subdivision

2012 ◽  
Vol 241-244 ◽  
pp. 81-85
Author(s):  
Wei Zhou ◽  
Jun Zhang ◽  
Si Qi Wang ◽  
Kai Zhu ◽  
Zi Li Xu
Keyword(s):  
Measurement System ◽  
High Frequency ◽  
High Speed ◽  
Excitation Power ◽  
Angle Measurement ◽  
Measuring System ◽  
Control Voltage ◽  
Display Module ◽  
Angle Measuring ◽  
And Control

For the inductosyn angle measuring system axial angle digital converter integral loop and the VCO linear range restricted problem of tracking speed and control voltage, angle measurement system has been developed, the angle measurement system based on time subdivision method. The system mainly consists of rotary table, excitation power, signal pick-up circuit, FPGA control module, display module, and serial communications modules and host computer. FPGA is used as control core in the angle measuring system, and the high-speed FPGA signal processing has satisfied the measurement requirements. Induction signal is subdivided by high-frequency clock pulse. Angle measuring system has achieved angle measurement and communication functions. The experimental results show that the angle measurement system accuracy is ±3".

Development of a Sliding Plate Rheometer to Measure the High Frequency Viscoelastic Properties of Polymer Melts

2007 ◽  
Vol 17 (6) ◽  
pp. 62563-1-62563-8
Author(s):  
Chelsea A. Braybrook ◽  
Jennifer A. Lee ◽  
Philip J. Bates ◽  
Marianna Kontopoulou
Keyword(s):  
Rheological Properties ◽  
High Frequency ◽  
Viscoelastic Properties ◽  
Parallel Plate ◽  
Polymer Melts ◽  
Measured Data ◽  
Rheological Models ◽  
Linear Viscoelastic ◽  
Good Agreement ◽  
Sliding Plate

Abstract A newly designed and constructed sliding plate rheometer is used to measure the high frequency (210 Hz) linear viscoelastic properties of two model polymers: polybutene (PB) and polydimethylsiloxane (PDMS). Using well-known rheological models, extrapolations of the viscoelastic measurements obtained on a rotational parallel plate rheometer to a frequency of 210 Hz are used to assess the performance of the high frequency sliding plate rheometer. Good agreement between the extrapolated and measured data demonstrates the ability of the sliding plate rheometer to measure the high frequency rheological properties of both Newtonian and shear-thinning materials.

The Microstructure of Steatite (Protoenstatite)

1985 ◽  
Vol 43 ◽  
pp. 236-237
Author(s):  
W. E. Lee ◽  
A. H. Heuer
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Magnesium Silicate ◽  
Beam Current ◽  
Glassy Matrix ◽  
Angle Of Incidence ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Argon Ions ◽  
High Temperature Polymorph

IntroductionTraditional steatite ceramics, made by firing (vitrifying) hydrous magnesium silicate, have long been used as insulators for high frequency applications due to their excellent mechanical and electrical properties. Early x-ray and optical analysis of steatites showed that they were composed largely of protoenstatite (MgSiO3) in a glassy matrix. Recent studies of enstatite-containing glass ceramics have revived interest in the polymorphism of enstatite. Three polymorphs exist, two with orthorhombic and one with monoclinic symmetry (ortho, proto and clino enstatite, respectively). Steatite ceramics are of particular interest a they contain the normally unstable high-temperature polymorph, protoenstatite.Experimental3mm diameter discs cut from steatite rods (∼10” long and 0.5” dia.) were ground, polished, dimpled, and ion-thinned to electron transparency using 6KV Argon ions at a beam current of 1 x 10-3 A and a 12° angle of incidence. The discs were coated with carbon prior to TEM examination to minimize charging effects.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

1992 ◽  
Vol 1 (4) ◽  
pp. 52-55 ◽  
Author(s):  
Gail L. MacLean ◽  
Andrew Stuart ◽  
Robert Stenstrom
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Low Frequency ◽  
Test System ◽  
Output Frequency ◽  
Frequency Effects ◽  
Adult Men ◽  
Frequency Responses ◽  
Significant Difference ◽  
Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

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