Measurement of Dynamic Bulk Modulus and Phase Angle Using ESPI

1986 ◽  
Vol 59 (2) ◽  
pp. 223-232 ◽  
Author(s):  
B. P. Holownia ◽  
A. C. Rowland
Keyword(s):  
Bulk Modulus ◽  
Phase Angle ◽  
Direct Method ◽  
Frequency Range ◽  
Rate Of Increase ◽  
Nitrile Rubbers ◽  
Novel Method

Abstract The measurement of the dynamic bulk modulus of elastomers by the direct method using ESPI has been achieved within the frequency range of 50–1000 Hz. The two types of Nitrile rubbers tested show that the dynamic bulk modulus increases with frequency, but the rate of increase depends on the type of rubber used. A novel method of measuring the phase angle using ESPI was successful in principle, although the resolution error on the oscilloscope prevented definite conclusions being reached regarding its variation with frequency.

Determination of Dynamic Bulk Modulus of Elastomers Using Pressure Measurement

1993 ◽  
Vol 66 (5) ◽  
pp. 749-753 ◽  
Author(s):  
B. P. Holownia ◽  
E. H. James
Keyword(s):  
Bulk Modulus ◽  
Pressure Measurement ◽  
Frequency Range ◽  
Novel Method ◽  
Pressure Changes

Abstract A novel method of determining dynamic bulk modulus of elastomers, by measurement of pressure changes of the fluid in which the specimen is immersed, was successful in principle. The frequency range covered was between 100 Hz and 1200 Hz which was limited by the power of the oscillator used.

What is the most accurate substitute for an invisible T1 slope in cervical radiographs? A comparative study of a novel method with previously reported substitutes

2021 ◽  
pp. 1-7
Author(s):  
Brian J. Park ◽  
Colin J. Gold ◽  
Royce W. Woodroffe ◽  
Satoshi Yamaguchi
Keyword(s):  
Linear Regression ◽  
Direct Method ◽  
Pearson Correlation ◽  
Regression Modeling ◽  
Reliable Estimate ◽  
Horizontal Line ◽  
T1 Slope ◽  
C7 Slope ◽  
Novel Method ◽  
Linear Regression Modeling

OBJECTIVE The ability to utilize the T1 slope is often limited by poor visibility on cervical radiographs. The C7 slope has been proposed as a reliable substitute but may have similar limitations of visibility. Herein, the authors propose a novel method that takes advantage of the superior visibility on CT to accurately substitute for the radiographic T1 slope and compare the accuracy of this method with previously reported substitutes. METHODS Lateral neutral standing cervical radiographs and cervical CT scans were examined. When the T1 slope was clearly visible on radiographs, the C3–7 slopes and T1 slope were measured. In CT method 1, a direct method, the T1 slope was measured from the upper endplate of T1 to the bottom edge of the CT image, assuming the edge was parallel to the horizontal plane. In CT method 2, an overlaying method, the T1 slope was calculated by superimposing the C7 slope angle measured on a radiograph onto the CT scan and measuring the angle formed by the upper endplate of T1 and the superimposed horizontal line of the C7 slope. A Pearson correlation with linear regression modeling was performed for potential substitutes for the actual T1 slope. RESULTS Among 160 patients with available noninstrumented lateral neutral cervical radiographs, the T1 slope was visible in only 54 patients (33.8%). A total of 52 patients met the inclusion criteria for final analysis. The Pearson correlation coefficients between the T1 slope and the C3–7 slopes, CT method 1, and CT method 2 were 0.243 (p = 0.083), 0.292 (p = 0.035), 0.609 (p < 0.001), 0.806 (p < 0.001), 0.898 (p < 0.001), 0.426 (p = 0.002), and 0.942 (p < 0.001), respectively. Linear regression modeling showed R2 = 0.807 for the correlation between C7 slope and T1 slope and R2 = 0.888 for the correlation between T1 slope with the CT method 2 and actual T1 slope. CONCLUSIONS The C7 slope can be a reliable predictor of the T1 slope and is more accurate than more rostral cervical slopes. However, this study disclosed that the novel CT method 2, an overlaying method, was the most reliable estimate of true T1 slope with a greater positive correlation than C7 slope. When CT studies are available in patients with an invisible T1 slope on cervical radiographs, CT method 2 should be used as a substitute for the T1 slope.

A Novel Non-Destructive Method for Measuring Elastic Moduli of Cultivated Cartilage Tissues

2007 ◽  
Vol 342-343 ◽  
pp. 853-856 ◽  
Author(s):  
Duk Young Jung ◽  
Yu Bong Kang ◽  
Toshie Tsuchiya ◽  
Sadami Tsutsumi
Keyword(s):  
Mechanical Properties ◽  
Bulk Modulus ◽  
Soft Tissues ◽  
Articular Chondrocytes ◽  
Collagen Gel ◽  
Accuracy And Precision ◽  
Novel Method ◽  
Silicone Rubbers ◽  
High Degree ◽  
Non Destructive

Accurate measurement of the mechanical properties of artificial or cultivated cartilage is a major factor for determining successive regeneration of defective soft tissues. In this study, we developed a novel method that enabled the bulk modulus (k-modulus) to be measured nondestructively using the relationship between volume and pressure of living soft tissues. In order to validate this method we estimated the bulk modulus of soft silicone rubbers using our new method and a conventional method. The results showed a 5 ~ 10% difference between the results obtained with the two methods. Our method was used subsequently to measure the mechanical properties of cultivated cartilage samples (collagen gel type), that had been incubated for four weeks in the presence or absence of human articular chondrocytes (HACs). Our experiments showed that cultivated cartilage tissues grown in the presence of HACs had a higher bulk modulus (120 ± 20 kPa) than samples grown without HACs (90 ± 15 kPa). The results indicated that our novel method offered an effective method for measurement of volume changes in minute living soft tissues, with the measurements having a high degree of accuracy and precision. Furthermore, this method has significant advantages over conventional approaches as it can be used to rapidly and accurately evaluate the strength of soft tissues during cultivation without causing damage to the specimen.

Apparatus for the Direct Determination of the Dynamic Bulk Modulus

1957 ◽  
Vol 30 (2) ◽  
pp. 449-459
Author(s):  
J. E. McKinney ◽  
S. Edelman ◽  
R. S. Marvin
Keyword(s):  
Natural Rubber ◽  
Bulk Modulus ◽  
Direct Measurement ◽  
Static Pressure ◽  
Direct Determination ◽  
Preliminary Evaluation ◽  
Air Bubbles ◽  
Frequency Range ◽  
Piezoelectric Crystals

Abstract An apparatus has been developed for the direct measurement of the real and imaginary parts of the dynamic bulk modulus of solid and liquid materials over the frequency range of 50 to 10,000 cps. Piezoelectric crystals serving as driver and detector, together with the sample and a confining liquid, are contained in a cavity small compared with the wavelength of sound at these frequencies. Static pressure is superposed to eliminate the effect of small air bubbles. The complex compliances of the sample, confining liquid, and the cavity, are additive in this region, where the compliance is pure dilatation. The dynamic compliances of several natural rubber-sulfur mixtures were obtained in a preliminary evaluation of the behavior of the apparatus.

Experimental Measurement of Dynamic Bulk Modulus Using Holography

1985 ◽  
Vol 58 (2) ◽  
pp. 258-268 ◽  
Author(s):  
B. P. Holownia
Keyword(s):  
Bulk Modulus ◽  
Room Temperature ◽  
Dynamic Pressure ◽  
Pressure Fluctuations ◽  
Limiting Factor ◽  
Frequency Range ◽  
Holographic Method ◽  
Indirect Methods ◽  
Servo Valve ◽  
Hydraulic Servo

Abstract The results show that the dynamic bulk modulus for NBR at room temperature is about 50% higher than the static bulk modulus in the frequency range of 1–200 Hz. The limiting factor was the servo-valve used which does not give enough dynamic pressure fluctuations above 200 Hz to obtain accurate results of the dynamic bulk modulus. The holographic method discussed here offers a number of advantages over other methods used in measuring dynamic bulk modulus. (i) The samples are of realistic size and any soft spots in the sample which would distort the results can be immediately identified. (ii) Dynamic bulk modulus can be measured accurately in the frequency range of 1 Hz–1000 Hz or higher, provided the hydraulic servo-valve used can respond in the frequency range. Work is already in hand which extends this frequency range to 1200 Hz. (iii) The change of volume of the sample is a direct measurement unlike other indirect methods, therefore, there is more confidence in the results.

scholarly journals ASSESSMENT OF UNCERTAINTY IN THE CALIBRATION PHASE ANGLE GENERATORS ON THE STATE PRIMARY STANDARD PHASE ANGLE BETWEEN TWO VOLTAGES AT THE FUNDAMENTAL FREQUENCY RANGE

2017 ◽  
Vol 0 (17) ◽  
pp. 32-39
Author(s):  
Величко Олег Миколайович ◽  
Шевкун Сергій Миколайович ◽  
Юлія Миколаївна Куліш ◽  
Марина Валеріївна Добролюбова
Keyword(s):  
Fundamental Frequency ◽  
Phase Angle ◽  
Primary Standard ◽  
The State ◽  
State Primary Standard ◽  
Frequency Range

scholarly journals Transglutaminase Shows Better Functionality on High Digestible, High Lysine Sorghum-Wheat Composite Dough and Bread, Compared to Normal Sorghum-Wheat Composites

2019 ◽  
Vol 7 (6) ◽  
pp. 877 ◽  
Author(s):  
Yunus Emre Tunçil ◽  
Mehtap Fevzioglu ◽  
Seda Arioglu-Tunçil ◽  
Gebisa Ejeta ◽  
Osvaldo H. Campanella ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Phase Angle ◽  
Strain Amplitude ◽  
Viscoelastic Properties ◽  
Elastic System ◽  
Frequency Range ◽  
High Lysine ◽  
Substitution Level ◽  
Linear Viscoelastic ◽  
Dough Rheological Properties

Highly digestible high-lysine (HDHL) sorghum-wheat composites have previously been shown to produce better composite dough and bread compared to normal sorghum-wheat composites. This study aimed to test whether improved HDHL lines can provide further enhanced functionality through the effects of transglutaminase (TG) enzyme to improve dough rheological properties. Sorghum-wheat composite doughs were made using HDHL and normal sorghum flours at substitution levels of 10, 20, and 30%, with and without 0.15% TG. Rheological properties of dough were tested using a mechanical spectrometer at 0.05% strain amplitude (within the linear viscoelastic region) over a 0.01- 50 rad/sec frequency range. A more elastic system was observed in HDHL sorghum-wheat composites above 10% substitution levels compared to normal sorghum-wheat composite dough. Addition of TG to HDHL sorghum-wheat composites resulted in a decrease in phase angle values at all substitution level, indicating that TG increased the dough elasticity. However, TG did not change viscoelastic properties of normal sorghum-wheat composites. Bread from HDHL sorghum-wheat composites had significantly higher (P

A Novel Method for Deriving Optimal Synchronism-Check Phase Angle in Transmission System

2016 ◽  
Vol 11 (5) ◽  
pp. 1084-1092
Author(s):  
Yun-Sik Oh ◽  
Gi-Hyeon Gwon ◽  
Chul-Hwan Kim ◽  
Jeong-Jae Yang
Keyword(s):  
Phase Angle ◽  
Transmission System ◽  
Novel Method ◽  
Check Phase

Self-Detection of Delamination in Active Fiber Composites

2008 ◽  
Vol 56 ◽  
pp. 447-452
Author(s):  
Dwo Wen Wang ◽  
Wen Chih Tsai ◽  
Ching Chung Yin
Keyword(s):  
Fiber Composites ◽  
Acoustic Sensors ◽  
Sinusoidal Voltage ◽  
Electric Impedance ◽  
Frequency Range ◽  
Bonding Condition ◽  
Active Fiber ◽  
Interdigital Electrodes ◽  
Novel Method ◽  
Active Fiber Composites

This paper presents a novel method to monitor the bonding condition of active fiber composites (AFCs). AFCs can be used as integrated acoustic sensors/actuators to compose functional structures because of their excellent properties. Debonds between AFC patch and host structure should be avoided and surveyed through its service life. A partially debonded patch bears an axial extensional vibration which is excited by a sinusoidal voltage and detected by the interdigital electrodes symmetrically aligned on opposite surfaces of the patch. The electric impedance and mechanical displacement of the AFC patch adhered on an aluminum plate were investigated in a broad frequency range. The modal characteristics depend on the size of debond and stiffness of adhesive in front of the edge of delamination. The debonding ratio of the AFC patch is in inverse proportion to the resonant frequency of the fundamental mode. Feasibility of self-detecting the progressive delamination between AFC patch and host plate is demonstrated through computational and experimental results.

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