scholarly journals Pressure-Responsive Conductive Poly(vinyl alcohol) Composites Containing Waste Cotton Fibers Biochar

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 125
Author(s):  
Mattia Bartoli ◽  
Daniele Torsello ◽  
Erik Piatti ◽  
Mauro Giorcelli ◽  
Amelia Carolina Sparavigna ◽  
...  
Keyword(s):  
Composite Materials ◽  
Smart Materials ◽  
Material Science ◽  
Applied Pressure ◽  
Filler Loading ◽  
Electromagnetic Properties ◽  
Cotton Fibers ◽  
Poly Vinyl Alcohol ◽  
Time Hopping ◽  
First Time

The development of responsive composite materials is among the most interesting challenges in contemporary material science and technology. Nevertheless, the use of highly expensive nanostructured fillers has slowed down the spread of these smart materials in several key productive sectors. Here, we propose a new piezoresistive PVA composite containing a cheap, conductive, waste-derived, cotton biochar. We evaluated the electromagnetic properties of the composites under both AC and DC regimes and as a function of applied pressure, showing promisingly high conductivity values by using over 20 wt.% filler loading. We also measured the conductivity of the waste cotton biochar from 20 K up to 350 K observing, for the first time, hopping charge transport in biochar materials.

Anisotropic Elasticity

1996 ◽  
Author(s):  
T. T. C. Ting
Keyword(s):  
Composite Materials ◽  
Elastic Constants ◽  
Piezoelectric Materials ◽  
Anisotropic Materials ◽  
Anisotropic Elasticity ◽  
Stress Singularities ◽  
Comprehensive Survey ◽  
The Subject ◽  
Key Topics ◽  
First Time

Anisotropic Elasticity offers for the first time a comprehensive survey of the analysis of anisotropic materials that can have up to twenty-one elastic constants. Focusing on the mathematically elegant and technically powerful Stroh formalism as a means to understanding the subject, the author tackles a broad range of key topics, including antiplane deformations, Green's functions, stress singularities in composite materials, elliptic inclusions, cracks, thermo-elasticity, and piezoelectric materials, among many others. Well written, theoretically rigorous, and practically oriented, the book will be welcomed by students and researchers alike.

scholarly journals Development of a Self-Powered Piezo-Resistive Smart Insole Equipped with Low-Power BLE Connectivity for Remote Gait Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4539
Author(s):  
Roberto de Fazio ◽  
Elisa Perrone ◽  
Ramiro Velázquez ◽  
Massimo De Vittorio ◽  
Paolo Visconti
Keyword(s):  
Low Power ◽  
Smart Materials ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Complete Characterization ◽  
Electric Signal ◽  
Sensing Matrix ◽  
Capacitive Accelerometer ◽  
Gait Parameters ◽  
Smart Insole

The evolution of low power electronics and the availability of new smart materials are opening new frontiers to develop wearable systems for medical applications, lifestyle monitoring, and performance detection. This paper presents the development and realization of a novel smart insole for monitoring the plantar pressure distribution and gait parameters; indeed, it includes a piezoresistive sensing matrix based on a Velostat layer for transducing applied pressure into an electric signal. At first, an accurate and complete characterization of Velostat-based pressure sensors is reported as a function of sizes, support material, and pressure trend. The realization and testing of a low-cost and reliable piezoresistive sensing matrix based on a sandwich structure are discussed. This last is interfaced with a low power conditioning and processing section based on an Arduino Lilypad board and an analog multiplexer for acquiring the pressure data. The insole includes a 3-axis capacitive accelerometer for detecting the gait parameters (swing time and stance phase time) featuring the walking. A Bluetooth Low Energy (BLE) 5.0 module is included for transmitting in real-time the acquired data toward a PC, tablet or smartphone, for displaying and processing them using a custom Processing® application. Moreover, the smart insole is equipped with a piezoelectric harvesting section for scavenging energy from walking. The onfield tests indicate that for a walking speed higher than 1 ms−1, the device’s power requirements (i.e., ) was fulfilled. However, more than 9 days of autonomy are guaranteed by the integrated 380-mAh Lipo battery in the total absence of energy contributions from the harvesting section.

scholarly journals S-N Curve Characterisation for Composite Materials and Prediction of Remaining Fatigue Life Using Damage Function

2021 ◽  
Vol 5 (3) ◽  
pp. 76
Author(s):  
Ho Sung Kim ◽  
Saijie Huang
Keyword(s):  
Fatigue Life ◽  
Composite Materials ◽  
Loading Rate ◽  
Theoretical Method ◽  
Damage Function ◽  
Simple Method ◽  
Arbitrary Choice ◽  
Number Of Cycles ◽  
First Time ◽  
Remaining Fatigue Life

S-N curve characterisation and prediction of remaining fatigue life are studied using polyethylene terephthalate glycol-modified (PETG). A new simple method for finding a data point at the lowest number of cycles for the Kim and Zhang S-N curve model is proposed to avoid the arbitrary choice of loading rate for tensile testing. It was demonstrated that the arbitrary choice of loading rate may likely lead to an erroneous characterisation for the prediction of the remaining fatigue life. The previously proposed theoretical method for predicting the remaining fatigue life of composite materials involving the damage function was verified at a stress ratio of 0.4 for the first time. Both high to low and low to high loadings were conducted for predicting the remaining fatigue lives and a good agreement between predictions and experimental results was found. Fatigue damage consisting of cracks and whitening is described.

Building Protection with Composite Materials Application

2017 ◽  
Vol 755 ◽  
pp. 286-291 ◽  
Author(s):  
Dávid Ágoston Balázs ◽  
Zoltán Nyikes ◽  
Tünde Kovács
Keyword(s):  
Composite Materials ◽  
Material Science ◽  
Terrorist Attacks ◽  
Syntactic Foams ◽  
Reinforced Composites ◽  
New Materials ◽  
Spherical Shells ◽  
Secondary Damage ◽  
Blast Effects ◽  
Blast Effect

Building protection on our century is very important because of the terrorist attacks. The old buildings in Europe aren’t enough strong again blast loads. Nowadays we know many different explosives and theirs effects of walls and human bodies. The detonation caused blast effect provokes building damage and fragmentation effects. The explosion caused damages, parts of bricks and fragments produce other secondary damage in other buildings and human bodies.It can’t protect the historical and old buildings by new walls and fences because of the cityscape. It needs to find new possibilities to improve the buildings resistance again blast effects. It needs a effectively thin and strong materials to reinforced the buildings walls. The new materials innovated by material science can be good solution for this project. These materials usually composites likes syntactic foams, spherical shells or carbon fields reinforced composites.

The Wood Composite Materials of Table Tennis Bat and Batting Techniques

2012 ◽  
Vol 583 ◽  
pp. 49-52
Author(s):  
Zhong Hai Wang ◽  
Ru Jian Yuan ◽  
Xiao Bing Fan
Keyword(s):  
Composite Materials ◽  
Material Science ◽  
High Performance ◽  
Technical Innovation ◽  
Wood Composite ◽  
Table Tennis ◽  
Tennis Racket

With the table tennis technical innovation and improvement of science, high-performance materials are used to manufacture of table tennis plate floor and help athletes have achieved better results. This article elaborated the wood composite materials’s impact on batting techniques through the analysis of the function of table tennis racket floor and its structure and capacity based on material science for provide the reference on manufacturing and selecting of table tennis racket.

scholarly journals Prospective Approach to the Anaerobic Bioconversion of Benzo- and Dibenzothiophene Sulfones to Sulfide

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1736 ◽  
Author(s):  
Olga Senko ◽  
Olga Maslova ◽  
Marina Gladchenko ◽  
Sergey Gaydamaka ◽  
Argam Akopyan ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Biogas Production ◽  
Poly Vinyl Alcohol ◽  
Sulfur Recovery ◽  
Actual Problem ◽  
Sulfate Reducing ◽  
Pure Cell ◽  
Reducing Bacteria ◽  
First Time ◽  
Anaerobic Bioconversion

Sulfur recovery from organic molecules such as toxic sulfones is an actual problem, and its solution through the use of environmentally friendly and nature-like processes looks attractive for research and application. For the first time, the possible bioconversion of organic sulfones (benzo-and dibenzothiophene sulfones) to inorganic sulfide under anaerobic conditions with simultaneous biogas production from glucose within a methanogenesis process is demonstrated. Biogas with a methane content of 50.7%–82.1% was obtained without H2S impurities. Methanogenesis with 99.7%–100% efficiency and 97.8%–100% conversion of benzo- and dibenzothiophene sulfones (up to 0.45 mM) to inorganic sulfide were obtained in eight days by using a combination of various anaerobic biocatalysts immobilized in a poly(vinyl alcohol) cryogel. Pure cell cultures of sulfate-reducing bacteria and/or H2-producing bacteria were tested as additives to the methanogenic activated sludge. The immobilized activated sludge “enhanced” by bacterial additives appeared to retain its properties and be usable multiple times for the conversion of sulfones under batch conditions.

scholarly journals The Terahertz Controlled Duplex Isolator: Physical Grounds and Numerical Experiment

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Konstantin Vytovtov ◽  
Said Zouhdi ◽  
Rostislav Dubrovka ◽  
Volodymyr Hnatushenko
Keyword(s):  
Oblique Incidence ◽  
Faraday Effect ◽  
Harmonic Wave ◽  
Analytical Form ◽  
Electromagnetic Properties ◽  
Anisotropy Axis ◽  
Dual Frequency ◽  
Plane Harmonic Wave ◽  
Axis Orientation ◽  
First Time

Electromagnetic properties of an anisotropic stratified slab with an arbitrary orientation of the anisotropy axis under an oblique incidence of a plane harmonic wave are studied. The dependence of the eigenwave wavenumbers and the reflection coefficient on an anisotropy axis orientation and frequency is investigated. For the first time, the expression for the translation matrix is obtained in the compact analytical form. The controlled two-way dual-frequency (duplex) isolator based on the above described slab is presented for the first time. It is based on the properties of the anisotropic structure described here but not on the Faraday effect.

URSS/PVA/WP Composite Materials: Preparation and Performance

2014 ◽  
Vol 968 ◽  
pp. 80-83
Author(s):  
Chuan Bao Wu ◽  
Bo Qiao
Keyword(s):  
Tensile Strength ◽  
Composite Materials ◽  
Rice Straw ◽  
Hot Pressing ◽  
Vinyl Alcohol ◽  
Tensile Elongation ◽  
Environmentally Friendly ◽  
Waste Paper ◽  
Poly Vinyl Alcohol ◽  
And Performance

A novel kind of environmentally friendly composite materials containing upper part of rice straw segments (URSS), poly (vinyl alcohol) (PVA) and waste paper (WP) were prepared by hot-pressing at 140°C for 10 min. The tensile strength, tensile elongation and hardness of composites were measured. Results showed that the tensile strength and the strength at tensile break of the composites first increased and then decreased with increasing PVA content. Tensile strength was higher than the strength at tensile break at different PVA contents, indicating that URSS/PVA/WP composite materials had certain toughness. Otherwise, URSS/PVA/WP composite materials had higher tensile strength than URSS/PVA composites. The tensile strengths of them were respectively 9.25 MPa and 3.9 MPa when prepared at PVA content of 40%. The hardness of composites lay between 90 and 96. Negligible difference exists in every composite.

Experimental Study on Piezoresistivity and Magnetoresistivity of Magnetorheological Elastomers

2010 ◽  
Vol 37-38 ◽  
pp. 444-447 ◽  
Author(s):  
Wei Qiang Ye ◽  
Yi Min Deng ◽  
Wei Wang
Keyword(s):  
Smart Materials ◽  
Magnetic Field Intensity ◽  
Nickel Content ◽  
Applied Pressure ◽  
Hysteresis Phenomenon ◽  
Magnetorheological Elastomer ◽  
Research Focus ◽  
Magnetorheological Elastomers ◽  
New Type ◽  
Low Magnetic Field

As a new type of smart materials, magnetorheological elastomer (MRE) has become a hot current research focus. However, the piezoresistivity and magnetoresistivity of MRE have not been well studied. In this paper, this was done by using a test rig developed by the authors. The experimental results showed that the conductivity of the MRE responded sensitively to the applied pressure, and a linear relationship between the resistivity of the MRE and the applied pressure can be observed within a certain range. Besides, the sensitivity of piezoresistivity is different among different ratios of metal content, and it becomes more obvious when using the nickel content. And, the magnetoresistivity of MRE is not obvious in a range of low magnetic field intensity, and there is also no hysteresis phenomenon about magnetoresistivity.

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