Investigation of the Electromechanical Sensory Potential of CNT-Polymer Nanocomposites Using Nano- and Micro-Scale Models

2008 ◽  
Author(s):  
Theodosis Theodosiou ◽  
Michalis Papadatos ◽  
Dimitris Saravanos
Keyword(s):  
Polymer Nanocomposites ◽  
Micro Scale ◽  
Scale Models

scholarly journals Bonded Concrete Overlays: A Brief Discussion on Restrained Shrinkage Deformations and Their Prediction Models

2019 ◽  
Vol 61 (2) ◽  
pp. 107-129
Author(s):  
Wojciech Cyron ◽  
Martin Nilsson ◽  
Mats Emborg ◽  
Ulf Ohlsson
Keyword(s):  
Prediction Models ◽  
Asphalt Pavement ◽  
Theoretical Explanation ◽  
Empirical Equations ◽  
Restrained Shrinkage ◽  
Micro Scale ◽  
Concrete Overlays ◽  
The Past ◽  
Scale Models ◽  
Thermal Dilation

Abstract Bonded concrete overlays (BCO) on bridge decks are beneficial solutions due to their superior properties as compared to the typical asphalt pavement. A significant number of overlays suffer however, from occurrence of cracks and delamination due to poor bond, and restrained shrinkage and thermal dilation. Over the past years different appraisals for estimation of the restrained deformations have been developed, from micro-scale models, based on poromechanics, to empirical equations as given in B3 or B4 models suggested by Bažant. This paper provides a short overview of calculation models along with a brief theoretical explanation of shrinkage mechanism.

scholarly journals A Multi-Point Meso–Micro Downscaling Method Including Atmospheric Stratification

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1191
Author(s):  
Renko Buhr ◽  
Hassan Kassem ◽  
Gerald Steinfeld ◽  
Michael Alletto ◽  
Björn Witha ◽  
...  
Keyword(s):  
Wind Energy ◽  
Single Point ◽  
Scale Model ◽  
Cfd Modeling ◽  
Modeling Framework ◽  
Site Assessment ◽  
Micro Scale ◽  
Scale Models ◽  
Wind Climate ◽  
Meso Scale

In wind energy site assessment, one major challenge is to represent both the local characteristics as well as general representation of the wind climate on site. Micro-scale models (e.g., Reynolds-Averaged-Navier-Stokes (RANS)) excel in the former, while meso-scale models (e.g., Weather Research and Forecasting (WRF)) in the latter. This paper presents a fast approach for meso–micro downscaling to an industry-applicable computational fluid dynamics (CFD) modeling framework. The model independent postprocessing tool chain is applied using the New European Wind Atlas (NEWA) on the meso-scale and THETA on the micro-scale side. We adapt on a previously developed methodology and extend it using a micro-scale model including stratification. We compare a single- and multi-point downscaling in critical flow situations and proof the concept on long-term mast data at Rödeser Berg in central Germany. In the longterm analysis, in respect to the pure meso-scale results, the statistical bias can be reduced up to 45% with a single-point downscaling and up to 107% (overcorrection of 7%) with a multi-point downscaling. We conclude that single-point downscaling is vital to combine meso-scale wind climate and micro-scale accuracy. The multi-point downscaling is further capable to include wind shear or veer from the meso-scale model into the downscaled velocity field. This adds both, accuracy and robustness, by minimal computational cost. The new introduction of stratification in the micro-scale model provides a marginal difference for the selected stability conditions, but gives a prospect on handling stratification in wind energy site assessment for future applications.

scholarly journals Learning continuum-scale models from micro-scale dynamics via Operator Regression.

2020 ◽  
Author(s):  
Ravi Patel ◽  
Nathaniel Trask ◽  
Mitchell Wood ◽  
Eric Cyr
Keyword(s):  
Micro Scale ◽  
Scale Models ◽  
Continuum Scale

Non-Destructive Investigation of Dispersion, Bonding, and Thermal Properties of Emerging Polymer Nanocomposites Using Close-Up Lens Assisted Infrared Thermography

MRS Advances ◽  
2020 ◽  
Vol 5 (14-15) ◽  
pp. 735-742
Author(s):  
Ali Ashraf ◽  
Nikhil Jani ◽  
Francis Farmer ◽  
Jennifer K. Lynch-Branzoi
Keyword(s):  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Polymer Nanocomposites ◽  
Polymer Nanocomposite ◽  
Thermal Imager ◽  
Ir Camera ◽  
Micro Scale ◽  
Matrix Interaction ◽  
Non Destructive ◽  
Insight Into

AbstractPolymer nanocomposites possess unique sets of properties that make them suitable for different applications, including structural and flame-retardant material, electromagnetic wave reflector, sensors, thin film transistor, flexible display, and many more. The properties of these nanocomposite are dependent on nanofiller dispersion and bonding with polymer matrix (i.e. particle-matrix interaction). Thermography is a non-destructive method that may be used to gain insight into dispersion and particle-matrix interaction. Infrared (IR) radiation emitted from these nanomaterial polymer composite depends on the emissivity of the individual components. In addition, during flash heating and cooling, different thermal conductivity of components in the nanocomposite can influence pixel intensity differently in the IR image or video being captured. We have used an economical mid wavelength IR camera Fluke RSE600 equipped with a close-up macro lens and algorithm based on MATLAB image processing toolbox to analyse dispersion, voids and thermal diffusivity of patented graphene polymer nanocomposite materials (G-PMC) in micro-scale. These G-PMCs can act as a standard material to determine the potential of our IR thermography technique due to their homogeneity and lack of impurity due to unique fabrication process. Thermal diffusivity and dispersion of nanoparticles in our G-PMCs was estimated after irradiation with a xenon flash lamp by spatially mapping transient IR radiations from different G-PMCs using the Fluke RSE600 thermal imager. Results from thermography experiments were compared with scanning electron microscope (SEM) and Raman spectroscopy results. Micro-scale thermography was able to detect millimetre scale thermal diffusivity variation in the injection molded G-PMC samples and relate it to change in dispersion of nanofillers, unlike SEM and Raman, where micro-scale measurements could not determine the reason behind millimetre scale property variation. We believe this low cost, fast, micro-scale, non-destructive technique will provide valuable insight into functional polymer nanocomposite fabrication and corresponding electrical and thermal properties.

scholarly journals An experimental investigation on tool wear behaviour of uncoated and coated micro-tools in micro-milling of graphene-reinforced polymer nanocomposites

2021 ◽  
Author(s):  
Niusha Shakoori ◽  
Guoyu Fu ◽  
Bao Le ◽  
Jibran Khaliq ◽  
Long Jiang ◽  
...  
Keyword(s):  
Tool Wear ◽  
Polymer Nanocomposites ◽  
Surface Quality ◽  
High Surface ◽  
Micro Milling ◽  
Wear Behaviour ◽  
Mechanical And Thermal Properties ◽  
High Surface Quality ◽  
Micro Scale ◽  
Micro Tools

AbstractNanomaterials such as graphene have been added to various matrices to enhance mechanical, thermal and electrical properties for various applications requiring intricate designs at the micro-scale. At this scale, mechanical micro-machining is utilised as post-processing to achieve high surface quality and dimensional accuracy while still maintaining high productivity. Therefore, in this study, the machinability of polymer nanocomposites in micro-scale (micro-machinability) is investigated. Graphene (0.3 wt%)-reinforced epoxy nanocomposites were fabricated using traditional solution mixing and moulding. The samples were then subjected to micro-milling at various cutting speeds using three different micro-tools, including uncoated, diamond and diamond-like carbon (DLC) tools. Mechanical and thermal properties of nanocomposite were also used to support the discussions. The result indicates that the DLC-coated tool shows better performance than the other tools for less tool wear, improved surface quality and less cutting forces.

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