Lacunarity exponent and Moran index: A complementary methodology to analyze AFM images and its application to chitosan films

Pinto, Erveton Pinheiro; Pires, Marcelo A.; Matos, Robert Saraiva; Zamora, R.R.M.; Menezes, Rodrigo P.; Araújo, Raquel Silva; Souza, Tiago Marcolino de

doi:10.1016/j.physa.2021.126192

Cited by 21 publications

(13 citation statements)

References 43 publications

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“…In this paper, the spatial autocorrelation function (Moran’s I ) is used to analyze the distribution characteristics of outbreak sites (whether agglomerated or not) (Zhao et al, 2020 ). Moran’s I is a standardized measure of spatial autocorrelation among variables of neighboring elements (Pinto et al, 2021 ), varying in the range of − 1 to 1. The closer Moran’s I index is to 0, the less self-correlated (random) H5N1 outbreak sites.…”

Section: Methodsmentioning

confidence: 99%

Environmental factors and spatiotemporal distribution characteristics of the global outbreaks of the highly pathogenic avian influenza H5N1

Chen

Zhang

Zhao

et al. 2022

Environ Sci Pollut Res

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The spread of highly pathogenic avian influenza H5N1 has posed a major threat to global public health. Understanding the spatiotemporal outbreak characteristics and environmental factors of H5N1 outbreaks is of great significance for the establishment of effective prevention and control systems. The time and location of H5N1 outbreaks in poultry and wild birds officially confirmed by the World Organization for Animal Health from 2005 to 2019 were collected. Spatial autocorrelation analysis and multidistance spatial agglomeration analysis methods were used to analyze the global outbreak sites of H5N1. Combined with remote sensing data, the correlation between H5N1 outbreaks and environmental factors was analyzed using binary logistic regression methods. We analyzed the correlation between the H5N1 outbreak and environmental factors and finally made a risk prediction for the global H5N1 outbreaks. The results show that the peak of the H5N1 outbreaks occurs in winter and spring. H5N1 outbreaks exhibit aggregation, and a weak aggregation phenomenon is noted on the scale close to 5000 km. Water distance, road distance, railway distance, wind speed, leaf area index (LAI), and specific humidity were protective factors for the outbreak of H5N1, and the odds ratio (OR) were 0.985, 0.989, 0.995, 0.717, 0.832, and 0.935, respectively. Temperature was a risk factor with an OR of 1.073. The significance of these ORs was greater than 95%. The global risk prediction map was obtained. Given that the novel coronavirus (COVID-19) is spreading globally, the methods and results of this study can provide a reference for studying the spread of COVID-19.

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Section: Methodsmentioning

confidence: 99%

Environmental factors and spatiotemporal distribution characteristics of the global outbreaks of the highly pathogenic avian influenza H5N1

Chen

Zhang

Zhao

et al. 2022

Environ Sci Pollut Res

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“…The lines used to estimate the Hurst coefficient (HC) display a suitable adjustment to the experimental data. All samples displayed HC > 5, indicating that their height distributions are homogeneous and with probability > 50% of repetition of the height values 43 . As can also be seen, the value of HC increases from 0.511 to 0.728, showing that the annealing temperature plays a critical role on the formation of topographic height distributions more homogeneous.…”

Section: Resultsmentioning

confidence: 95%

Advanced nano-texture, optical bandgap, and Urbach energy analysis of NiO/Si heterojunctions

Dejam

Sabbaghzadeh

Ghaderi

et al. 2023

Sci Rep

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Due to the large number of industrial applications of transparent conductive oxides (TCOs), this study focuses on one of the most important metal oxides. The RF-magnetron sputtering method was used to fabricate NiO thin films on both quartz and silicon substrates at room temperature under flow of Argon and Oxygen. The sputtered samples were annealed in N2 atmosphere at 400, 500, and 600 °C for 2 hours. Using the AFM micrographs and WSXM 4.0 software, the basic surface parameters, including root mean square roughness, average roughness, kurtosis, skewness, etc., were computed. Advanced surface parameters were obtained by the Shannon entropy through a developed algorithm, and the power spectral density and fractal succolarity were extracted by related methods. Optical properties were studied using a transmittance spectrum to achieve the optical bandgap, absorption coefficient, Urbach energy, and other optical parameters. Photoluminescence properties also showed interesting results in accordance with optical properties. Finally, electrical characterizations and I–V measurements of the NiO/Si heterojunction device demonstrated that it can be used as a good diode device.

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“…Lacunarity coefficient is a dimensionless number that quantifies the degree of heterogeneity of a surface. Surfaces with higher values have a more heterogeneous gap distribution, while smaller values reveal surfaces with a more homogeneous distribution. , …”

Section: Computational Details: Advanced Fractal Parametersmentioning

confidence: 99%

Effect of Fe Doping on the Surface Morphology and Supercapacitor Properties of Sr(OH)₂ Thin Films: A Fractal Approach

Yadav

Priya

et al. 2021

J. Phys. Chem. C

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Fractal concepts have been employed to explore the morphological evolution of Sr(OH) 2 thin films prepared by the successive ionic layer adsorption and reaction (SILAR) method on stainless steel (SS) substrate. The surface morphology of each sample was captured using atomic force microscopy (AFM). Interface width, lateral correlation length, and roughness exponent were computed. Our study reveals that as doping is increased, the roughness exponent decreases and the fractal dimension increases. In all cases, the value of the roughness exponent was found to be greater than 0.5, indicating that the height fluctuations at neighboring pixels are correlated positively and exhibit persistent behavior and memory effect. Advanced fractal parameters such as lacunarity coefficient (σ), Hurst coefficient (HC), fractal succolarity (FS), and surface entropy (SE) are also calculated. Our study reveals that the surface entropy does not show any significant change, indicating a globally uniform surface. Furthermore, the local surface slope is found to play a crucial role in the performance of supercapacitive electrodes. Fractal analysis indicates that electrodes with larger fractal dimension are better for supercapacitor applications. These observations are corroborated with the 0.5 atom % Fe/Sr(OH) 2 doped sample. This sample exhibits both the highest fractal dimension and a specific capacity of 776 C g −1 at a scan rate of 5 mV s −1 . The materials with higher fractal dimension could thus be a strong candidate for the fabrication of highly efficient supercapacitors.

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Lacunarity exponent and Moran index: A complementary methodology to analyze AFM images and its application to chitosan films

Cited by 21 publications

References 43 publications

Environmental factors and spatiotemporal distribution characteristics of the global outbreaks of the highly pathogenic avian influenza H5N1

Environmental factors and spatiotemporal distribution characteristics of the global outbreaks of the highly pathogenic avian influenza H5N1

Advanced nano-texture, optical bandgap, and Urbach energy analysis of NiO/Si heterojunctions

Effect of Fe Doping on the Surface Morphology and Supercapacitor Properties of Sr(OH)₂ Thin Films: A Fractal Approach

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Lacunarity exponent and Moran index: A complementary methodology to analyze AFM images and its application to chitosan films

Cited by 21 publications

References 43 publications

Environmental factors and spatiotemporal distribution characteristics of the global outbreaks of the highly pathogenic avian influenza H5N1

Environmental factors and spatiotemporal distribution characteristics of the global outbreaks of the highly pathogenic avian influenza H5N1

Advanced nano-texture, optical bandgap, and Urbach energy analysis of NiO/Si heterojunctions

Effect of Fe Doping on the Surface Morphology and Supercapacitor Properties of Sr(OH)2 Thin Films: A Fractal Approach

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Product

Resources

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Effect of Fe Doping on the Surface Morphology and Supercapacitor Properties of Sr(OH)₂ Thin Films: A Fractal Approach