scholarly journals A Hybrid Two-Axis Force Sensor for the Mesoscopic Structural Superlubricity Studies

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3431
Author(s):  
Sun ◽  
Wu ◽  
Li ◽  
Zheng ◽  
Lin
Keyword(s):  
Real Time ◽  
Frictional Force ◽  
Normal Load ◽  
Force Sensor ◽  
Solid Surfaces ◽  
Mems Sensors ◽  
Shear Forces ◽  
Electromechanical Systems ◽  
Normal Forces ◽  
Storage Technologies

Structural superlubricity (SSL) is a state of nearly zero friction and zero wear between two directly contacted solid surfaces. Recently, SSL was achieved in mesoscale and thus opened the SSL technology which promises great applications in Micro-electromechanical Systems (MEMS), sensors, storage technologies, etc. However, load issues in current mesoscale SSL studies are still not clear. The great challenge is to simultaneously measure both the ultralow shear forces and the much larger normal forces, although the widely used frictional force microscopes (FFM) and micro tribometers can satisfy the shear forces and normal forces requirements, respectively. Here we propose a hybrid two-axis force sensor that can well fill the blank between the capabilities of FFM and micro tribometers for the mesoscopic SSL studies. The proposed sensor can afford 1mN normal load with 10 nN lateral resolution. Moreover, the probe of the sensor is designed at the edge of the structure for the convenience of real-time optical observation. Calibrations and preliminary experiments are conducted to validate the performance of the design.

scholarly journals Flexible Shear and Normal Force Sensor Using Only One Layer of Polyvinylidene Fluoride Film

2019 ◽  
Vol 9 (20) ◽  
pp. 4339 ◽  
Author(s):  
Lee ◽  
Chung ◽  
Oh ◽  
Cha
Keyword(s):  
Real Time ◽  
Polyvinylidene Fluoride ◽  
Normal Force ◽  
Force Sensor ◽  
Applied Force ◽  
Pvdf Film ◽  
Simple Process ◽  
Flexible Sensor ◽  
Normal Forces

We have proposed a flexible sensor that can sense shear and normal forces, and can be fabricated through a simple process using only one layer of polyvinylidene fluoride (PVDF) film. For the measurement of shear and normal forces, one layer of PVDF film was sealed in a three-dimensionally structured polydimethylsiloxane (PDMS). In the structure, the sensor produced voltage signals corresponding to the shear and normal forces. Using this property, we aimed to demonstrate how to sense the magnitude and direction of the force applied to the sensor from its output voltages. Furthermore, the proposed sensor with a 2 × 2 array was able to measure the applied force in real time.

Motion of masses with asymmetric and symmetric friction. Application to fault sliding

2021 ◽  
Author(s):  
Rui Xiang Wong ◽  
Elena Pasternak ◽  
Arcady Dyskin
Keyword(s):  
Frictional Force ◽  
Normal Load ◽  
Power Spectra ◽  
Inertial Force ◽  
Friction Reduction ◽  
Relative Mass ◽  
Hydraulic Fractures ◽  
Driving Frequency ◽  
Stick Slip ◽  
Friction Forces

<p>This study analyses a situation when a geological fault contains a section of anisotropic gouge with inclined symmetry axes (e.g. inclined layering), Bafekrpour et al. [1]. Such gouge in a constrained environment induces, under compression, asymmetric friction (different friction forces resisting sliding in the opposite directions). The rest of the gouge produces conventional symmetric friction. A mass-spring model of the gouge with asymmetric and symmetric friction sections is proposed consisting of a mass with asymmetric friction connected through a spring to another mass with symmetric friction. These masses are set on a base subjected to vibration. A parametric analysis is performed on this system. Two distinct characteristic regimes were observed: <em>recurrent movement</em> resembling stick-slip motion similar to predicted by [2] and <em>sub-frictional movement</em>. Recurrent movement arises when the inertial force is sufficient to overcome frictional force of a block with symmetric friction. Sub-frictional movement occurs when the inertial force is not sufficient to overcome frictional force of an equivalent system with only symmetric friction. The sub-frictional movement is produced by the force in the connecting spring increased due to the movement of the asymmetric friction block in the direction characterised by low friction. We formulate the criterion at which sub-frictional movement occurs. The occurrence of sub-frictional depends upon the relative mass of the symmetric and asymmetric friction sections, as well as the amplitude and driving frequency of the excitation. Power spectra of the produced vibrations are determined for both regimes. The results can shed light on mechanisms of sliding over pre-existing discontinuities and their effect on seismic event generation and propagation of hydraulic fractures in the presence of discontinuities.</p><p>[1] Bafekrpour,<strong> </strong>E., A.V. Dyskin, E. Pasternak, A. Molotnikov and Y. Estrin (2015), Internally architectured materials with directionally asymmetric friction. <em>Scientific Reports</em>, 5, Article 10732.</p><p>[2] Pasternak, E. A.V. Dyskin and I. Karachevtseva, 2020. Oscillations in sliding with dry friction. Friction reduction by imposing synchronised normal load oscillations. <em>International Journal of Engineering Science</em>, 154, 103313.</p><p><strong>Acknowledgement</strong>. AVD and EP acknowledge support from the Australian Research Council through project DP190103260.</p>

scholarly journals The Giardia Median Body Protein Is a Ventral Disc Protein That Is Critical for Maintaining a Domed Disc Conformation during Attachment

2012 ◽  
Vol 11 (3) ◽  
pp. 292-301 ◽  
Author(s):  
David J. Woessner ◽  
Scott C. Dawson
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Shear Forces ◽  
Bare Area ◽  
Body Protein ◽  
Content Type ◽  
Intestinal Epithelia ◽  
Normal Forces ◽  
Membrane Contacts ◽  
Ventral Disc

ABSTRACTGiardiahas unique microtubule structures, including the ventral disc, the primary organelle of attachment to the host, and the median body, a structure of undefined function. During attachment, the ventral disc has a domed conformation and enablesGiardiato attach to the host intestinal epithelia within seconds. The mechanism of attachment via the ventral disc and the overall structure, function, and assembly of the ventral disc are not well understood. Our recent proteomic analysis of the ventral disc indicated that the median body protein (MBP), previously reported to localize exclusively to the median body, was primarily localized to the ventral disc. Using high-resolution light and electron microscopy, we confirm that the median body protein localizes primarily to the overlap zone of the ventral disc. The MBP also occasionally localized to the median body during prophase. To define the contribution of MBP to the ventral disc structure, we depleted MBP using an anti-MBP morpholino. We found that the ventral disc was no longer able to form properly and that the disc structure often had an aberrant nondomed or flattened horseshoe conformation. The ability of attached anti-MBP morpholino-treated trophozoites to withstand shear forces and normal forces was significantly decreased. Most notably, the plasma membrane contacts with the surface, including those of the bare area, were defective after the anti-MBP knockdown. To our knowledge, this is the first ventral disc protein whose depletion directly alters ventral disc structure, confirming that the domed ventral disc conformation is important for robust attachment.

A Novel Approach to Time Series Forecasting Using Model-Free Adaptive Control Framework

2020 ◽  
Author(s):  
Meenakshi Narayan ◽  
Ann Majewicz Fey
Keyword(s):  
Time Series ◽  
Adaptive Control ◽  
Real Time ◽  
Time Series Data ◽  
Mean Squared Error ◽  
Force Sensor ◽  
Sensor Data ◽  
Series Data ◽  
Model Free ◽  
Control Framework

Abstract Sensor data predictions could significantly improve the accuracy and effectiveness of modern control systems; however, existing machine learning and advanced statistical techniques to forecast time series data require significant computational resources which is not ideal for real-time applications. In this paper, we propose a novel forecasting technique called Compact Form Dynamic Linearization Model-Free Prediction (CFDL-MFP) which is derived from the existing model-free adaptive control framework. This approach enables near real-time forecasts of seconds-worth of time-series data due to its basis as an optimal control problem. The performance of the CFDL-MFP algorithm was evaluated using four real datasets including: force sensor readings from surgical needle, ECG measurements for heart rate, and atmospheric temperature and Nile water level recordings. On average, the forecast accuracy of CFDL-MFP was 28% better than the benchmark Autoregressive Integrated Moving Average (ARIMA) algorithm. The maximum computation time of CFDL-MFP was 49.1ms which was 170 times faster than ARIMA. Forecasts were best for deterministic data patterns, such as the ECG data, with a minimum average root mean squared error of (0.2±0.2).

Storage Infrastructure for Big Data and Cloud

2014 ◽  
pp. 110-128 ◽  
Author(s):  
Anupama C. Raman
Keyword(s):  
Big Data ◽  
Real Time ◽  
Data Storage ◽  
Unstructured Data ◽  
Storage Area Networks ◽  
Storage Technology ◽  
Object Based ◽  
Storage Area ◽  
Storage Technologies ◽  
Big Data Storage

Unstructured data is growing exponentially. Present day storage infrastructures like Storage Area Networks and Network Attached Storage are not very suitable for storing huge volumes of unstructured data. This has led to the development of new types of storage technologies like object-based storage. Huge amounts of both structured and unstructured data that needs to be made available in real time for analytical insights is referred to as Big Data. On account of the distinct nature of big data, the storage infrastructures for storing big data should possess some specific features. In this chapter, the authors examine the various storage technology options that are available nowadays and their suitability for storing big data. This chapter also provides a bird's eye view of cloud storage technology, which is used widely for big data storage.

Geometric nonlinearity and mechanical anisotropy in strained helical nanoribbons

Nanoscale ◽  
2014 ◽  
Vol 6 (16) ◽  
pp. 9443-9447 ◽  
Author(s):  
Z. Chen
Keyword(s):  
Drug Delivery ◽  
Geometric Nonlinearity ◽  
Mechanical Anisotropy ◽  
Mems Sensors ◽  
Active Materials ◽  
Electromechanical Systems

Fabrication and synthesis of helical nanoribbons have received increasing attention because of the broad applications of helical nanostructures in nano-elecromechanical/micro-electromechanical systems (NEMS/MEMS), sensors, active materials, drug delivery,etc.

Self-Powered Force Sensor Based on Thinned Bulk PZT for Real-Time Cutaneous Activities Monitoring

2018 ◽  
Vol 39 (8) ◽  
pp. 1226-1229 ◽  
Author(s):  
Zhiran Yi ◽  
Hanjia Yang ◽  
Yingwei Tian ◽  
Xiaoxue Dong ◽  
Jingquan Liu ◽  
...  
Keyword(s):  
Real Time ◽  
Force Sensor ◽  
Self Powered
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