scholarly journals Vibration-induced nanoscale friction modulation on piezoelectric materials

Friction ◽  
2022 ◽  
Author(s):  
Jiawei Cao ◽  
Qunyang Li
Keyword(s):  
Piezoelectric Materials ◽  
Effective Means ◽  
Mechanical Vibration ◽  
Friction Model ◽  
Friction Reduction ◽  
Small Scale ◽  
Vibrational Amplitude ◽  
Vibration Source ◽  
Reduction Effect ◽  
Piezoelectric Thin Film

AbstractMechanical vibration, as an alternative of application of solid/liquid lubricants, has been an effective means to modulate friction at the macroscale. Recently, atomic force microscopy (AFM) experiments and model simulations also suggest a similar vibration-induced friction reduction effect for nanoscale contact interfaces, although an additional external vibration source is typically needed to excite the system. Here, by introducing a piezoelectric thin film along the contact interface, we demonstrate that friction measured by a conductive AFM probe can be significantly reduced (more than 70%) when an alternating current (AC) voltage is applied. Such real-time friction modulation is achieved owing to the localized nanoscale vibration originating from the intrinsic inverse piezoelectric effect, and is applicable for various material combinations. Assisted by analysis with the Prandtl—Tomlinson (P—T) friction model, our experimental results suggest that there exists an approximately linear correlation between the vibrational amplitude and the relative factor for perturbation of sliding energy corrugation. This work offers a viable strategy for realizing active friction modulation for small-scale interfaces without the need of additional vibration source or global excitation that may adversely impact device functionalities.

scholarly journals Mechanical Vibration Signal Denoising Using Quantum-Inspired Standard Deviation Based on Subband Based Gaussian Mixture Model

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Aidong Xu ◽  
Wenqi Huang ◽  
Peng Li ◽  
Huajun Chen ◽  
Jiaxiao Meng ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Gaussian Mixture Model ◽  
Mixture Model ◽  
Mechanical Vibration ◽  
Vibration Signal ◽  
Gaussian Mixture ◽  
Wavelet Coefficients ◽  
Denoising Method ◽  
Reduction Effect ◽  
Thresholding Function

Aiming at improving noise reduction effect for mechanical vibration signal, a Gaussian mixture model (SGMM) and a quantum-inspired standard deviation (QSD) are proposed and applied to the denoising method using the thresholding function in wavelet domain. Firstly, the SGMM is presented and utilized as a local distribution to approximate the wavelet coefficients distribution in each subband. Then, within Bayesian framework, the maximum a posteriori (MAP) estimator is employed to derive a thresholding function with conventional standard deviation (CSD) which is calculated by the expectation-maximization (EM) algorithm. However, the CSD has a disadvantage of ignoring the interscale dependency between wavelet coefficients. Considering this limit for the CSD, the quantum theory is adopted to analyze the interscale dependency between coefficients in adjacent subbands, and the QSD for noise-free wavelet coefficients is presented based on quantum mechanics. Next, the QSD is constituted for the CSD in the thresholding function to shrink noisy coefficients. Finally, an application in the mechanical vibration signal processing is used to illustrate the denoising technique. The experimental study shows the SGMM can model the distribution of wavelet coefficients accurately and QSD can depict interscale dependency of wavelet coefficients of true signal quite successfully. Therefore, the denoising method utilizing the SGMM and QSD performs better than others.

A Study on Small Scale Associated Gas FLNG Utilizing Small Scale LNG Carriers to Near-By Onshore LNG Plant

2016 ◽  
Author(s):  
X. C. Nguyen ◽  
Komla Miheaye ◽  
Mun-gyu Kim ◽  
Howard Newman ◽  
Dong-hoon Yoo ◽  
...  
Keyword(s):  
Short Range ◽  
Storage Capacity ◽  
Effective Means ◽  
Production Capacity ◽  
Cost Effective ◽  
Oil Fields ◽  
Small Scale ◽  
Associated Gas ◽  
Small Capacity ◽  
Stranded Gas

This study describes a FLNG specifically designed to monetize Associated Gas (AG) of producing oil fields located within convenient distance of an existing LNG Plant or Port with LNG storage facility. Limited production capacity combined with short range small capacity shuttles and limited LNG storage capacity, provide a cost effective means for LNG production. This FLNG is designed to service an existing industry and does not require development of stranded gas discoveries.

scholarly journals The description of friction of silicon MEMS with surface roughness: virtues and limitations of a stochastic Prandtl–Tomlinson model and the simulation of vibration-induced friction reduction

2010 ◽  
Vol 1 ◽  
pp. 163-171 ◽  
Author(s):  
W Merlijn van Spengen ◽  
Viviane Turq ◽  
Joost W M Frenken
Keyword(s):  
Surface Roughness ◽  
Critical Role ◽  
Measurement Data ◽  
Friction Model ◽  
Friction Reduction ◽  
Atomic Scale ◽  
Mems Devices ◽  
Tomlinson Model ◽  
Atomic Force ◽  
On Chip

We have replaced the periodic Prandtl–Tomlinson model with an atomic-scale friction model with a random roughness term describing the surface roughness of micro-electromechanical systems (MEMS) devices with sliding surfaces. This new model is shown to exhibit the same features as previously reported experimental MEMS friction loop data. The correlation function of the surface roughness is shown to play a critical role in the modelling. It is experimentally obtained by probing the sidewall surfaces of a MEMS device flipped upright in on-chip hinges with an AFM (atomic force microscope). The addition of a modulation term to the model allows us to also simulate the effect of vibration-induced friction reduction (normal-force modulation), as a function of both vibration amplitude and frequency. The results obtained agree very well with measurement data reported previously.

scholarly journals Mass marking of juvenile Schizothorax wangchiachii (Fang) with alizarin red S and evaluation of stock enhancement in the Jinping area of the Yalong River

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4142 ◽  
Author(s):  
Kun Yang ◽  
Shu Li ◽  
Xiaoshuai Liu ◽  
Weixiong Gan ◽  
Longjun Deng ◽  
...  
Keyword(s):  
Large Scale ◽  
Condition Factor ◽  
Effective Means ◽  
Stock Enhancement ◽  
Alizarin Red S ◽  
Small Scale ◽  
Instantaneous Growth Rate ◽  
Alizarin Red ◽  
Total Length ◽  
Yalong River

Schizothorax wangchiachii is a key fish species in the stock enhancement program of the Yalong River hydropower project, China. Alizarin red S (ARS) was used to mark large numbers of juvenile S. wangchiachii in the Jinping Hatchery and later used to evaluate stock enhancement in the Jinping area of the Yalong River. In a small-scale pilot study, 7,000 juveniles of the 2014 cohort were successfully marked by immersion in ARS solution, and no mortality was recorded during the marking process. The ARS mark in the fish otoliths remained visible 20 months later. In the large-scale marking study, approximately 600,000 juveniles of the 2015 cohort were successfully marked. Mortalities of both marked and unmarked juveniles were very low and did not differ significantly. Total length, wet mass and condition factor did not differ significantly between unmarked and marked individuals after three months. On 24 July 2015, about 840,000 Jinping Hatchery-produced young S. wangchiachii, including 400,000 marked individuals, were released at two sites in the Jinping area. Recapture surveys showed that (1) marked and unmarked S. wangchiachii did not differ significantly in total length, wet mass and condition factor; (2) stocked individuals became an important part of recruitment of the 2015 cohort; (3) instantaneous growth rate of marked individuals tended to slightly increase; and (4) most stocked individuals were distributed along a 10–15 km stretch near the release sites. These results suggest that the ARS method is a cost-efficient way to mass mark juvenile S. wangchiachii and that releasing juveniles is an effective means of stock recruitment.

Offloading Operability of Small Scale AG FLNG With Side-by-Side Moored Small Scale LNG Carrier in Offshore West Africa

2017 ◽  
Author(s):  
Mun-sung Kim ◽  
Eric Morilhat ◽  
X. C. Nguyen ◽  
Bo-hee Kim ◽  
Jung-moon Jang ◽  
...  
Keyword(s):  
West Africa ◽  
Relative Motion ◽  
Structural Integrity ◽  
Effective Means ◽  
Production Capacity ◽  
Cost Effective ◽  
Body Motion ◽  
Small Scale ◽  
Associated Gas ◽  
High Level

This study describes one of the technical solutions for Small Scale FLNG (SSFLNG)[1] development specifically designed to monetize Associated Gas (AG) of producing oil fields located within convenient distance of an existing LNG Plant or Port with LNG storage facility. Limited production capacity combined with short range small scale LNG carriers (SSLNGC), provide a cost effective means for LNG production. Ship to ship off-loading operation by loading arm has been considered in AG SSFLNG. Produced LNG is to be off-loaded from the SSFLNG to side-by-side moored SSLNGC. Relative motion and dynamic load acting on loading arm system in side-by-side mooring arrangement is one of key factors to estimate the offloading operability of the AG SSFLNG. In this paper, a numerical two-body motion analysis for the side-by-side moored SSFLNG in frequency- and time-domain is carried out. Also, the basic engineering work is carried out for the marine loading arms (MLA). Since the MLA reacts approximately as a linear system, it is calculated by a full spectral RAO analysis for each of the worst load cases issued from the spectral ranking. All loads and stresses inside the MLA are verified in accordance with EN1474-1[2] for the situations identified in the previous step. A high level fatigue analysis focused on the cryogenic swivel joints is carried out. Based on the numerical calculation for relative motion in side-by-side moored FLNG, we have been performed structural assessment for MLA in several environment conditions. The structural integrity of both MLA and the LNGC manifold are validated during offloading for Offshore West Africa.

Lubrication of saliva layer on oral and throat mucosa and its friction reduction effect

2020 ◽  
Vol 2020 (0) ◽  
pp. OS10-04
Author(s):  
Kenji SHIMOKASA ◽  
Hiromichi OBARA ◽  
Hiroshi MIZUNUMA
Keyword(s):  
Friction Reduction ◽  
Reduction Effect

Energy Harvesting From PZT Nanofibers

2007 ◽  
Vol 1034 ◽  
Author(s):  
Yong Shi ◽  
Yong Shi
Keyword(s):  
Energy Harvesting ◽  
Dynamic Loading ◽  
Lead Zirconate Titanate ◽  
Output Voltage ◽  
Mechanical Vibration ◽  
Titanium Substrate ◽  
Average Diameter ◽  
Lead Zirconate ◽  
Electrospinning Process ◽  
Vibration Source

AbstractIn this paper, we demonstrated that Lead Zirconate Titanate (PZT) nanofibers can be used to harvest energy from dynamic loading and mechanical vibration. PZT nanofibers were fabricated by electrospinning process. SEM image of PZT nanofibers has shown that the average diameter of these fibers is about 150nm, which can be tuned from 50nm to 200 nm by varying the composition and viscosity of the precursor for electrospining. Titanium substrate with ZrO2 layer was used to collect the PZT nanofibers for the demonstration of energy harvesting from dynamic loading. The largest output voltage is 170mV under 0.5% strain; the frequency of the output voltage is the same as that of the input loading. Silicon substrate with trenches was used to collect the nanofibers for energy harvesting from vibration. The output voltage generated from 150Hz sinusoid vibration source has peak voltages of 64.9mV and -95.9mV. These experimental results suggest that PZT nanofibers have great potentials for energy harvesting from environments and being used as nanogenerators. Further study is under the way to optimize the design and improve the efficiency.

scholarly journals Laboratory study on response of underwater cohesive sediment to columnar vibration source

2018 ◽  
Vol 54 (3) ◽  
pp. 193-202
Author(s):  
Peng Zhao ◽  
Feier Chen ◽  
Guoliang Yu
Keyword(s):  
Pressure Distribution ◽  
Experimental Observation ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Near Field ◽  
Mechanical Vibration ◽  
Cohesive Sediment ◽  
Vibration Source ◽  
Soil Pressure

Abstract This paper investigates the responses of cohesive sediment to mechanical vibration by experimental observation, containing: (1) the dynamic soil pressure, dynamic pore water pressure and dynamic acceleration to the vibration source; (2) the soil pressure distribution in the near field centered in an artificial columnar vibration source. Under the mechanical vibration with a frequency of 200 Hz and an amplitude of 1.15 mm, the dynamic soil pressure, dynamic pore water pressure and dynamic acceleration of underwater viscous sediment were measured in the sediment of four different depositing conditions. Results of the dynamic soil pressure, dynamic pore water pressure and dynamic acceleration of underwater viscous sediment in the near field responding to artificial vibration source are exhibited and discussed. It is found that, excited by the sinusoidal vibrator, the soil pressure presents a response of statistical sinusoidal fluctuation with the same frequency to the vibration source. In the sediment of lower initial yield stresses, the soil pressure distribution distinctly tends to firstly increase and then decrease with distance. The amplitude of the soil pressure is attenuated exponentially with distance.

Modeling and Simulation of Monocrystal Piezoelectric Generator

2013 ◽  
Vol 785-786 ◽  
pp. 1203-1207
Author(s):  
Lei Zhang ◽  
Li Qing Fang ◽  
De Qing Guo ◽  
Yong Chao Chen
Keyword(s):  
Modeling And Simulation ◽  
Numerical Method ◽  
Analytical Model ◽  
Piezoelectric Materials ◽  
Mechanical Vibration ◽  
Adhesive Layer ◽  
Operation Mechanism ◽  
Material Parameters ◽  
Voltage Stress ◽  
Piezoelectric Generator

The expressions of voltage, stress and amount of charge of monocrystal piezoelectric generator under concentrated exterior pressure was derived in order to proving the precision and validity of numerical method applied to piezoelectric materials' distribution sensing and the study of operation mechanism ignore the influence of adhesive layer. An analytical model of the monocrystal piezoelectric generator was established by using the mechanical vibration theory. And the effects of the structural and material parameters on the output energy are analyzed.

Sign in / Sign up

Export Citation Format

Share Document