scholarly journals The Study of Magnetoimpedance Effect for Magnetoelectric Laminate Composites with Different Magnetostrictive Layers

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6397
Author(s):  
Lei Chen ◽  
Yao Wang ◽  
Tianhong Luo ◽  
Yongkang Zou ◽  
Zhongjie Wan
Keyword(s):  
Young’S Modulus ◽  
Relative Permeability ◽  
Magnetic Permeability ◽  
Experimental Results ◽  
Laminate Composites ◽  
Saturation Field ◽  
Magnetostrictive Material ◽  
Material Characteristics ◽  
Magnetostrictive Strain ◽  
Theoretical Analyses

The rectangular magnetoelectric (ME) composites of Metglas/PZT and Terfenol-D/PZT are prepared, and the effects of a magnetostrictive layer’s material characteristics on the magnetoimpedance of ME composite are discussed and experimentally investigated. The theoretical analyses show that the impedance is not only dependent on Young’s modulus and the magnetostrictive strain of magnetostrictive material but is also influenced by its relative permeability. Compared with Terfenol-D, Metglas possesses significantly higher magnetic permeability and larger magnetostrictive strain at quite low Hdc due to the small saturation field, resulting in the larger magnetoimpedance ratio. The experimental results demonstrate that the maximum magnetoimpedance ratios (i.e., ΔZ/Z) of Metglas/PZT composite are about 605.24% and 239.98% at the antiresonance and resonance, respectively. Specifically, the maximum ΔZ/Z of Metglas/PZT is 8.6 times as high as that of Terfenol-D/PZT at the antiresonance. Such results provide the fundamental guidance in the design and fabrication of novel multifunction devices based on the magnetoimpedance effect of ME composites.

scholarly journals A parametric prediction of the Young’s modulus of polymers enhanced with ΜWCNTs

2018 ◽  
Vol 233 ◽  
pp. 00025
Author(s):  
P.V. Polydoropoulou ◽  
K.I. Tserpes ◽  
Sp.G. Pantelakis ◽  
Ch.V. Katsiropoulos
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Experimental Results ◽  
Scale Model ◽  
Fe Model ◽  
Multi Scale ◽  
Unit Cells ◽  
Random Dispersion

In this work a multi-scale model simulating the effect of the dispersion, the waviness as well as the agglomerations of MWCNTs on the Young’s modulus of a polymer enhanced with 0.4% MWCNTs (v/v) has been developed. Representative Unit Cells (RUCs) have been employed for the determination of the homogenized elastic properties of the MWCNT/polymer. The elastic properties computed by the RUCs were assigned to the Finite Element (FE) model of a tension specimen which was used to predict the Young’s modulus of the enhanced material. Furthermore, a comparison with experimental results obtained by tensile testing according to ASTM 638 has been made. The results show a remarkable decrease of the Young’s modulus for the polymer enhanced with aligned MWCNTs due to the increase of the CNT agglomerations. On the other hand, slight differences on the Young’s modulus have been observed for the material enhanced with randomly-oriented MWCNTs by the increase of the MWCNTs agglomerations, which might be attributed to the low concentration of the MWCNTs into the polymer. Moreover, the increase of the MWCNTs waviness led to a significant decrease of the Young’s modulus of the polymer enhanced with aligned MWCNTs. The experimental results in terms of the Young’s modulus are predicted well by assuming a random dispersion of MWCNTs into the polymer.

scholarly journals Testing of yarn abrasion

2013 ◽  
Vol 13 (1) ◽  
pp. 22-27
Author(s):  
G. Krupincová ◽  
J. Hatipoglu
Keyword(s):  
Abrasion Resistance ◽  
Fiber Material ◽  
Experimental Results ◽  
Mechanical Parameters ◽  
Yarn Quality ◽  
Material Characteristics ◽  
Quality Testing

Abstract There exist a lot of methodologies, which can be used for yarn quality testing. Abrasion resistance and its measurement for raw and sized yarn can help in the judgment of yarn weaving-ability. This article concentrates on the possibility of yarn abrasion expression and testing. Relation among fiber material characteristics, selected yarn structural, and mechanical parameters is discussed and a few experimental results are shown.

Simulation and experimentation of a magnetorheological brake with adjustable gap

2016 ◽  
Vol 28 (12) ◽  
pp. 1614-1626 ◽  
Author(s):  
Wan-Li Song ◽  
Dong-Heng Li ◽  
Yan Tao ◽  
Na Wang ◽  
Shi-Chao Xiu
Keyword(s):  
Magnetorheological Fluid ◽  
Structure Design ◽  
Experimental Results ◽  
Wear Property ◽  
Braking Performance ◽  
Braking Torque ◽  
The Difference ◽  
The Impact ◽  
Theoretical Analyses ◽  
Magnetostatic Simulation

The aim of this work is to investigate the effect of the small magnetorheological fluid gap on the braking performance of the magnetorheological brake. In this article, theoretical analyses of the output torque are given first, and then the operating principle and design details of the magnetorheological brake whose magnetorheological fluid gap can be altered are presented and discussed. Next, the magnetic circuit of the proposed magnetorheological brake is conducted and further followed by a magnetostatic simulation of the magnetorheological brakes with different sizes of fluid gap. A prototype of the magnetorheological brake is fabricated and a series of tests are carried out to evaluate the braking performance and torque stability, as well as the verification of the simulation results. Experimental results show that the braking torque increases with the increase in the current, and the difference for the impact of the fluid gap on braking performance is huge under different currents. The rules, which the experimental results show, have an important significance on both the improvement of structure design for magnetorheological brake and the investigation of the wear property under different fluid gaps.

scholarly journals Multimedia Quality Integration Using Piecewise Function

2011 ◽  
Vol 1 ◽  
pp. 375-380
Author(s):  
Shu Ai Wan ◽  
Kai Fang Yang ◽  
Hai Yong Zhou
Keyword(s):  
Visual Quality ◽  
Experimental Results ◽  
Integration Model ◽  
Quality Performance ◽  
Piecewise Function ◽  
Proposed Model ◽  
Constant Coefficients ◽  
Theoretical Analyses ◽  
Different Levels

In this paper the important issue of multimedia quality evaluation is concerned, given the unimodal quality of audio and video. Firstly, the quality integration model recommended in G.1070 is evaluated using experimental results. Theoretical analyses aide empirical observations suggest that the constant coefficients used in the G.1070 model should actually be piecewise adjusted for different levels of audio and visual quality. Then a piecewise function is proposed to perform multimedia quality integration under different levels of the audio and visual quality. Performance gain observed from experimental results substantiates the effectiveness of the proposed model.

Ensuring Correctness, Completeness, and Freshness for Outsourced Tree-Indexed Data

2010 ◽  
pp. 693-710
Author(s):  
Tran Khanh Dang
Keyword(s):  
Research Work ◽  
Data Integrity ◽  
Experimental Results ◽  
Actual Data ◽  
Service Model ◽  
Security Issues ◽  
Data Owner ◽  
Database Service ◽  
Outsourced Database ◽  
Theoretical Analyses

In an outsourced database service model, query assurance takes an important role among well-known security issues. To the best of our knowledge, however, none of the existing research work has dealt with ensuring the query assurance for outsourced tree-indexed data. To address this issue, the system must prove authenticity and data integrity, completeness, and freshness guarantees for the result set. These objectives imply that data in the result set is originated from the actual data owner and has not been tampered with; the server did not omit any tuples matching the query conditions; and the result set was generated with respect to the most recent snapshot of the database. In this paper, we propose a vanguard solution to provide query assurance for outsourced tree-indexed data on untrusted servers with high query assurance and at reasonable costs. Experimental results with real datasets confirm the effciency of our approach and theoretical analyses.

TUNABLE WAVEFORM GENERATORS USING SINGLE DUAL-CURRENT OUTPUT OTAs

2008 ◽  
Vol 17 (06) ◽  
pp. 1193-1202 ◽  
Author(s):  
YU-KANG LO ◽  
HUNG-CHUN CHIEN ◽  
HUANG-JEN CHIU
Keyword(s):  
Pulse Width ◽  
Experimental Results ◽  
Pulse Waveform ◽  
Operational Transconductance Amplifier ◽  
Switching Element ◽  
Passive Components ◽  
Current Output ◽  
Transconductance Amplifier ◽  
Theoretical Analyses

Two novel electronic-tunable waveform generators using a single dual-current output operational transconductance amplifier (DO-OTA) with a few passive components are proposed in this paper. The first one can produce symmetrical square and triangular waveforms simultaneously. Based on the first topology, an additional N-MOS is adopted as a switching element to construct the second proposed circuit, which can generate a pulse waveform by a negative triggering signal. The repetitive frequency and pulse width of the presented circuits are adjustable by external passive components. Moreover, the output levels of the proposed circuits can be controlled by the DO-OTA's bias currents. These waveform generators feature more compact configurations compared to the existing designs. Experimental results are close to the theoretical analyses.

Measurement of the Isothermal Volume Dilation Accompanying the Unilateral Extension of Rubber

1959 ◽  
Vol 32 (2) ◽  
pp. 428-433
Author(s):  
Fred G. Hewitt ◽  
Robert L. Anthony
Keyword(s):  
Molecular Weight ◽  
Young’S Modulus ◽  
Experimental Results ◽  
Molecular Weights ◽  
Rubber Specimen ◽  
A Value ◽  
Fractional Increase ◽  
Internal Agreement ◽  
Good Agreement

Abstract The fractional increase in volume accompanying the isothermal extension of soft gum rubber was measured for four rubber samples at mean extensions of 14, 33, and 51%. The chain molecular weights Mc of the four samples were 5500, 5100, 4400, and 3000, with an estimated uncertainty of about 10% in each value of Mc. The observed fractional increase in volume ranged from 3.2×10−5 to 142×10−5, the latter value being observed for the sample of lowest chain molecular weight and at the extension of 51%. The experimental results for each sample have been represented by theoretical curves based on Gee's expression for the fractional increase in volume as a function of the sample extension. The theoretical curves exhibit good agreement with those of Gee, Stern, and Treloar. The process of fitting the theoretical curves to the experimental points constituted a determination of Young's modulus E for each rubber specimen. As a check on the experimental results, and also on the theory employed, determinations of E were also made by two additional methods, namely, from rough stess-strain curves, and from the relation E=3γρRT/Mc. With one exception, the internal agreement between the three determinations of E for the four different samples was satisfactory. The exception noted can probably be ascribed to the use of too small a value of Mc for the sample of lowest chain molecular weight.

scholarly journals Theoretical and experimental investigation of MWCNT dispersion effect on the elastic modulus of flexible PDMS/MWCNT nanocomposites

2021 ◽  
Vol 11 (1) ◽  
pp. 55-64
Author(s):  
Pardis Ghahramani ◽  
Kamran Behdinan ◽  
Rasool Moradi-Dastjerdi ◽  
Hani E. Naguib
Keyword(s):  
Elastic Modulus ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Testing Machine ◽  
Experimental Tests ◽  
Weight Fraction ◽  
Experimental Results ◽  
Multiwalled Carbon ◽  
Displacement Mode ◽  
Theoretical Predictions

Abstract In this article, Young’s modulus of a flexible piezoresistive nanocomposite made of a certain amount of multiwalled carbon nanotube (MWCNT) contents dispersed in polydimethylsiloxane (PDMS) has been investigated using theoretical and experimental approaches. The PDMS/MWCNT nanocomposites with the governing factor of MWCNT weight fraction (e.g., 0.1, 0.25, and 0.5 wt%) were synthesized by the solution casting fabrication method. The nanocomposite samples were subjected to a standard compression test to measure their elastic modulus using Instron Universal testing machine under force control displacement mode. Due to the costs and limitations of experimental tests, theoretical predictions on the elasticity modulus of such flexible nanocomposites have also been performed using Eshelby–Mori–Tanaka (EMT) and Halpin–Tsai (HT) approaches. The theoretical results showed that HT’s approach at lower MWCNT contents and EMT’s approach at higher MWCNT contents have a better agreement to experimental results in predicting the elastic modulus of PDMS/MWCNT nanocomposites. The experimental results indicated that the inclusion of MWCNT in the PDMS matrix resulted in a noticeable improvement in Young’s modulus of PDMS/MWCNT nanocomposite at small values of MWCNT contents (up to w f = 0.25%); however, exceeding this nanofiller content did not elevate Young’s modulus due to the emergence of MWCNT agglomerations in the nanocomposite structure.

scholarly journals Variable Geometry Pipe Diffusers

1996 ◽  
Author(s):  
J. W. Salvage
Keyword(s):  
Flow Characteristics ◽  
Experimental Results ◽  
The Other ◽  
Variable Geometry ◽  
Inlet Flow ◽  
Design Performance ◽  
Flow Recirculation ◽  
Surge Margin ◽  
Theoretical Analyses

Theoretical analyses and experimental results are reported for two unique variable geometry techniques used with pipe diffusers to enhance off-design performance. One technique mechanically closes the diffuser throat in an unusual manner. The other allows flow recirculation to close the throat artificially while attempting to improve diffuser inlet flow characteristics. Results clearly show that surge margin may be significantly improved by either method and that flow recirculation may offer improved efficiency.

Relation between the ratio of elastic work to the total work of indentation and the ratio of hardness to Young's modulus for a perfect conical tip

2009 ◽  
Vol 24 (3) ◽  
pp. 590-598 ◽  
Author(s):  
J. Chen ◽  
S.J. Bull
Keyword(s):  
Numerical Simulation ◽  
Elastic Modulus ◽  
Linear Relationship ◽  
Young’S Modulus ◽  
Excellent Agreement ◽  
Material Properties ◽  
Experimental Results ◽  
Total Work ◽  
Scaling Relationship ◽  
Reduced Modulus

A linear relationship between the ratio of elastic work to the total indentation work and hardness to reduced modulus, i.e., We/Wt = λ H/Er, has been derived analytically and numerically in a number of studies and has been widely accepted. However, the scaling relationship between We/Wt and H/Er has recently been questioned, and it was found that λ is actually not a constant but is related to material properties. In this study, a new relationship between We/Wt and H/Er has been derived, which shows excellent agreement with numerical simulation and experimental results. We also propose a method for obtaining the elastic modulus and hardness of a material without invoking the commonly used Oliver and Pharr method. Furthermore, it is demonstrated that this method is less sensitive to tip imperfections than the Oliver and Pharr approach is.

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