Application of Multifractal Analysis for Research of Structural Materials

2021 ◽  
Vol 24 (4) ◽  
pp. 338-347
Author(s):  
M. L. Kheifetz ◽  
V. T. Senyut ◽  
A. G. Kolmakov ◽  
B. M. Bazrov ◽  
S. A. Klimenko ◽  
...  

Application of multifractal analysis for qualitative and quantitative description of structural materials is demonstrated. This makes it possible to evaluate the system’s characteristics of structures and to characterize the processes of self-organization in the materials. Formation of friction surface structures for aluminum alloys with Al2O3 and SiC additives in the scuffing mode is considered under comparable thermodynamic conditions. The addition of SiC, in comparison with Al2O3 , is less conducive to fragmentation and increase in the frequency of seizure and rupture processes. The addition of graphite into a composite material reinforced with SiC leads to increase in the degree of non-equilibrium of the thermodynamic conditions for the formation of the structures. Additional introduction of graphite further enhances the difference between materials with additions of Al2O3 and SiC, and this leads to the formation of the least ordered structures of the friction surface.

1994 ◽  
Vol 340 ◽  
Author(s):  
Bing-Lin Gu ◽  
Jing-Zhi Yu ◽  
Xiao Hu ◽  
Kaoru Ohno ◽  
Yoshiyuki Kawazoe

ABSTRACTA concentration wave method for several interpenetrating Bravais sublattices is presented by considering the intralayer and interlayer effective interactions and the difference between the surface layers and the deeper layers in III – V alloys. The ground state ordered structures of ternary III – V semiconductor alloys are deduced and a dynamic model is established.


2018 ◽  
Vol 4 (4) ◽  
pp. 3-13
Author(s):  
Ирина Турова ◽  
Irina Turova ◽  
София Григорьева ◽  
Sofiya Grigoryeva ◽  
Ольга Ожогина ◽  
...  

We have studied Ca II K line profiles, using two time series of spectrograms taken in two regions near the solar disk center. In each of the regions, the spectrograph slit cut out several areas of the quiet region and a plage. For the selected chromospheric structures, we have derived K line profiles and have defined a number of parameters that characterize the spatial and temporal variations of the profiles. The analysis of profile shapes in different structures belonging to the same moment of time has shown that there are structures whose profiles differ only slightly from each other in the photosphere, but differ dramatically in the chromosphere. The structures begin to differ from the level of formation of K1 and continue to differ further in the chromosphere. There are, however, structures which begin to differ at the level of the photosphere and continue to differ in the chromosphere. The difference between profile shapes in different structures is likely to be associated both with different thermodynamic conditions and with different magnetic field topology at a given point at a given time. We have examined temporal variations of the K Ca II line profiles in structural chromospheric elements, which are caused by the process of K2v-grains. In most of the studied areas of the chromospheric structures, the brightening of the K2v peak develops according to the “common” scenario: at the time of maximum bright-ness, the line shifts toward the red side. There are, however, cases when the brightening of the K2v peak occurs with a shift of the line to the violet side or with no shift at all. We have constructed scatter plots for some pairs of profile parameters related to intensities at characteristic points of the profile and their shifts. A correlation has been found between intensities in the center and wings of the K line. The correlation between shifts of the K2v and K2r peaks is very weak or completely absent.


2020 ◽  
Vol 520 ◽  
pp. 146307 ◽  
Author(s):  
Raul Zazo ◽  
Javier Solis ◽  
José A. Sanchez-Gil ◽  
Rocio Ariza ◽  
Rosalia Serna ◽  
...  

2020 ◽  
Vol 10 (21) ◽  
pp. 7692
Author(s):  
Ge Yan ◽  
Heqin Cheng ◽  
Lizhi Teng ◽  
Wei Xu ◽  
Yuehua Jiang ◽  
...  

Riverbed micro-topographical features, such as crest and trough, flat bed, and scour pit, indicate the evolution of fluvial geomorphology, and have an influence on the stability of underwater structures and overall scour pits. Previous studies on bedform feature extraction have focused mainly on the rhythmic bed surface morphology and have extracted crest and trough, while flat bed and scour pit have been ignored. In this study, to extend the feature description of riverbeds, geomorphic elements mapping was used by employing three geomorphic element classification methods: Wood’s criteria, a self-organization map (SOM) technique, and geomorphons. The results showed that geomorphic element mapping can be controlled by adjusting the slope tolerance and curvature tolerance of Wood’s criteria, using the map unit number and combination of the SOM technique and the flatness of geomorphons. Relatively flat bed can be presented using “plane”, “flat planar”, and “flat” elements, while scour pit can be presented using a “pit” element. A comparison of the difference between parameter settings for landforms and bedforms showed that SOM using 8 or 10 map units is applicable for land and underwater surface and is thus preferentially recommended for use. Furthermore, the use of geomorphons is recommended as the optimal method for characterizing bedform features because it provides a simple element map in the absence of area loss.


Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1031
Author(s):  
Michael Dasbach ◽  
Hendrik M. Reinhardt ◽  
Norbert A. Hampp

Laser-induced periodic surface structures (LIPSS) provide an elegant solution for the generation of highly ordered periodic patterns on the surface of solids. In this study, LIPSS are utilized for the formation of periodic platinum nanowire arrays. In a process based on laser-stimulated self-organization, platinum thin films, sputter-deposited onto silicon, are transformed into nanowire arrays with an average periodicity of 538 nm. The width of the platinum nanowires is adjustable in a range from 20 nm to 250 nm by simply adjusting the thickness of the initial platinum thin films in a range from 0.3 nm to 4.3 nm. With increasing width, platinum nanowires show a rising tendency to sink into the surface of the silicon wafer, thus indicating alloying between platinum and silicon upon LIPSS-formation by a nanosecond-pulsed laser. The Pt/silicon wires may be etched away, leaving a complementary nanostructure in the silicon surface.


Biochimie ◽  
2019 ◽  
Vol 162 ◽  
pp. 77-87
Author(s):  
Lyubov Filatova ◽  
David Donovan ◽  
Steven Swift ◽  
Vladimir Pugachev ◽  
Georgy Emelianov ◽  
...  

2019 ◽  
Vol 24 (2) ◽  
pp. 68-75
Author(s):  
Narayan Subedi ◽  
Indra Prasad Subedi

The diversity of insect pollinators and their impact on crop yield of mustard were studied in Kusma, Parbat, Nepal from December 2018 to April 2019 in four blocks with each having 12 m2 areas. Two plots; treatment and control, were established in each block. Insect diversity was observed from 8 to 16 hrs, with the interval of an hour for three consecutive months (Jan-Feb). Eighty mustard plants were randomly selected, 40 from each plot just before flowering to find the impact of insect pollination on crop yield and these selected plants were examined for various qualitative and quantitative parameters. Altogether 16 species of pollinator insects belonging to five orders and nine families were recorded. Hymenoptera (36 %) was the most abundant order visiting mustard flowers followed by Diptera (34 %), Coleoptera (17 %), Lepidoptera (12 %) and Heteroptera (1 %). The most abundant family was Apidae (35.64 %), followed by Syrphidae (31.84 %). Apis cerana and Eristalis sp. were the most important pollinator insects of mustard. Seven species were found foraging both on pollen and nectar, four species foraging only on nectar and remaining five as casual visitors. The peak foraging activities of majority of the insects were observed between 12 hr to 14 hr. A significant difference was observed in the number of pods (59.80 ± 1.967 and 70.47 ± 2.431), fruit set (70.55 ± 1.362 and 80.94 ± 0.638), number of seeds per pods (16.70 ± 0.248 and 19.30 ± 0.330), diameter of seed (0.133 ± 0.2547 and 0.275 ± 0.0051) and weight of 100 dry seeds (0.33 ± 0.058 and 0.48 ± 0.023) in control and treatment plots whereas, the difference was non-significant in case of pod length between control and treatment plots (P=0.163).


1995 ◽  
Vol 68 (2) ◽  
pp. 297-310 ◽  
Author(s):  
B. Meissner

Abstract The statistical theory of bound rubber and the polymer-filler gel formation theory are shown to offer a satisfactory quantitative description of a set of experimental bound-rubber data recently obtained by Wolff, Wang, Tan (Rubber Chem. Technol. 66, 163 (1993)) on SBR compounds filled with 17 furnace blacks covering the whole range of rubber grades. The observed decrease of bound-rubber content per unit of interfacial area with increasing loading and/or specific surface area of carbon black is explained by the theory as being due to the statistical nature of the adsorption process. A correlation was found to exist between specific surface activity of filler D (adjustable parameter of the theory, number of active sites per unit surface area) and filler structure, the latter being characterized by the difference between DBP absorption and crushed DBP absorption. Also, D was found to increase with loading of a high-structure black. The two effects are ascribed to filler aggregates breakdown during mixing, which leads to a new active surface formation for polymer bonding.


Holzforschung ◽  
2000 ◽  
Vol 54 (3) ◽  
pp. 255-261 ◽  
Author(s):  
Sara Canas ◽  
M. Conceição Leandro ◽  
M. Isabel Spranger ◽  
A. Pedro Belchior

Summary The influence of botanical species (Quercus and Castanea sativa) and geographical origin (Portugal—three different sites, France and North America) on the qualitative and quantitative content of some extractable low molecular weight phenolic compounds was assessed by HPLC. Chestnut wood had the highest total content of low molecular weight phenolic compounds, followed by the Portuguese oaks and the French oaks, whereas the American oak had the lowest content of these compounds. The contents of phenolic acids, phenolic aldehydes, scopoletin and umbelliferone were significantly different among the studied woods. Both the botanical species and the geographical origin affect the content of low molecular weight organic compounds of woods used in Portuguese cooperage. The results also show that the botanical species seem to be more important than the geographical origin to explain the difference in the wood phenolic composition. So, the separation of trees according to their origin is of considerable interest for coopers and winemakers to choose wisely the woods for the ageing of brandies.


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