Fractal and Lacunarity Analyses: Quantitative Characterization of Hierarchical Surface Topographies

2016 ◽  
Vol 22 (1) ◽  
pp. 168-177 ◽  
Author(s):  
Edwin J. Y. Ling ◽  
Phillip Servio ◽  
Anne-Marie Kietzig
Keyword(s):  
Processing Parameters ◽  
Surface Structures ◽  
Quantitative Characterization ◽  
Sem Images ◽  
Length Scales ◽  
Sem Image ◽  
Multiple Length Scales ◽  
Surface Topographies ◽  
Lacunarity Analysis

AbstractBiomimetic hierarchical surface structures that exhibit features having multiple length scales have been used in many technological and engineering applications. Their surface topographies are most commonly analyzed using scanning electron microscopy (SEM), which only allows for qualitative visual assessments. Here we introduce fractal and lacunarity analyses as a method of characterizing the SEM images of hierarchical surface structures in a quantitative manner. Taking femtosecond laser-irradiated metals as an example, our results illustrate that, while the fractal dimension is a poor descriptor of surface complexity, lacunarity analysis can successfully quantify the spatial texture of an SEM image; this, in turn, provides a convenient means of reporting changes in surface topography with respect to changes in processing parameters. Furthermore, lacunarity plots are shown to be sensitive to the different length scales present within a hierarchical structure due to the reversal of lacunarity trends at specific magnifications where new features become resolvable. Finally, we have established a consistent method of detecting pattern sizes in an image from the oscillation of lacunarity plots. Therefore, we promote the adoption of lacunarity analysis as a powerful tool for quantitative characterization of, but not limited to, multi-scale hierarchical surface topographies.

Fabrication and Characterization of Polycaprolactone (PCL)/Gelatin Electrospun Fibers

2014 ◽  
Vol 554 ◽  
pp. 52-56 ◽  
Author(s):  
Mim Mim Lim ◽  
Naznin Sultana ◽  
Azli Bin Yahya
Keyword(s):  
Fiber Diameter ◽  
Electrospun Fiber ◽  
Weight Ratio ◽  
Processing Parameters ◽  
Electrospun Fibers ◽  
Average Fiber Diameter ◽  
Polymer Blending ◽  
Electrospinning Technique ◽  
Sem Image

Over the past few decades, there has been considerable interest in developing electrospun fibers by using electrospinning technique for various applications. Polymer blending is one of the most effective methods in providing desired properties. In this study, synthetic polymer polycaprolactone (PCL) was blended together with natural polymer gelatin where both of them have different properties. It is done by using electrospinning technique. 10 %w/v and 14 %w/v PCL/gelatin electrospun fibers were successfully electrospun with different weight ratio. Processing parameters were set constant in this study and only solution parameters were altered. The optimized electrospun fiber formed was 14 %w/v PCL/gelatin 70:30 with average fiber diameter of 246.30 nm. No beaded fiber was formed in this scanning electron microscope (SEM) image. The result obtained also showed that by increasing the overall polymeric concentration of PCL/gelatin, average fiber diameter decreases. Fiber diameter was also found decreasing with the increase of the concentration of gelatin in the same concentratoin of PCL/gelatin blended electrospun fiber. Blending of PCL and gelatin in different weight ratio had provided different properties of electrospun fibers. It is believed that blended electrospun fibers can be used for biomedical applications.

Quantitative Characterization of the Structure of PP/Layered Silicate Nanocomposites at Various Length Scales

2008 ◽  
Vol 267 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Zita Dominkovics ◽  
Károly Renner ◽  
Béla Pukánszky ◽  
Béla Pukánszky
Keyword(s):  
Layered Silicate ◽  
Quantitative Characterization ◽  
Length Scales ◽  
Silicate Nanocomposites

scholarly journals Investigation of the Effect of Magnification, Accelerating Voltage, and Working Distance on the 3D Digital Reconstruction Techniques

Scanning ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Seyed Mahmoud Bayazid ◽  
Nicolas Brodusch ◽  
Raynald Gauvin ◽  
Michela Relucenti
Keyword(s):  
Spherical Particles ◽  
Reconstruction Technique ◽  
Quantitative Characterization ◽  
Sem Images ◽  
Digital Reconstruction ◽  
Backscattered Electron ◽  
Working Distance ◽  
Backscattered Signals ◽  
2D Images

In this study, the effect of Scanning Electron Microscopy (SEM) parameters such as magnification ( M ), accelerating voltage ( V ), and working distance (WD) on the 3D digital reconstruction technique, as the first step of the quantitative characterization of fracture surfaces with SEM, was investigated. The 2D images were taken via a 4-Quadrant Backscattered Electron (4Q-BSE) detector. In this study, spherical particles of Ti-6Al-4V (15-45 μm) deposited on the silicon substrate were used. It was observed that the working distance has a significant influence on the 3D digital rebuilding method via SEM images. The results showed that the best range of the working distance for our system is 9 to 10 mm. It was shown that by increasing the magnification to 1000x, the 3D digital reconstruction results improved. However, there was no significant improvement by increasing the magnification beyond 1000x. In addition, results demonstrated that the lower the accelerating voltage, the higher the precision of the 3D reconstruction technique, as long as there are clean backscattered signals. The optimal condition was achieved when magnification, accelerating voltage, and working distance were chosen as 1000x, 3 kV, and 9 mm, respectively.

Multiscale Characterization of Spatial Heterogeneity in Multiphase Composite Microstructures

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
M. A. Tschopp ◽  
G. B. Wilks ◽  
J. E. Spowart
Keyword(s):  
Spatial Heterogeneity ◽  
Reaction Yield ◽  
Length Scale ◽  
Length Scales ◽  
Phase Mixing ◽  
Multiple Length Scales ◽  
Three Phase ◽  
Reaction Stoichiometry ◽  
Multiphase Composite

A computational characterization technique is presented for assessing the spatial heterogeneity of two reactant phases in a three-phase chemically reactive composite. This technique estimates the reaction yield on multiple microstructure length scales based on the segregation of the two reactant phases and the expected reaction stoichiometry. The result of this technique is a metric, quantifying the effectiveness of phase mixing in a particular microstructure as a function of length scale. Assuming that the proportionate mixing of reactant phases on multiple length scales will enhance reaction kinetics and the overall level of reaction completion, this tool can subsequently be used as a figure-of-merit for optimizing microstructure via appropriate processing. To illustrate this point, an example is shown where a bimodal three-phase microstructure has a higher reaction yield at every length scale when compared with a monomodal three-phase microstructure with the same constituent loading.

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