Size effect characteristics of structural surfaces by improved projective covering method

AbstractAccurate characteristic of structural surfaces roughness at the relevant scale is very important to understand mechanical properties of rock mass discontinuities. So, a systematic investigation has been carried out to understand the effect of scale on the structural surface roughness by fractal dimension method. Firstly, considering the shortcoming of the projective covering method (PCM), we improved this method based on stochastic approach. Secondly, to investigate the size effect of the structural surface roughness, we selected six sampling windows, respectively, from the central and four corners part of structural planes (2 m × 2 m). The sampling windows range from 62.5 mm × 62.5 mm to 2000 mm × 2000 mm. And then, we calculated fractal parameters of the different size surfaces using improved projective covering method (IPCM) at the same resolution. Thirdly, we discussed a new method of determining reasonable size of structural surfaces by the parameter $$\Delta D_{\max }^{SD}$$ Δ D max SD . This parameter is difference of the maximum fractal dimension of the same size structural surface in different regions. The results show that: (1) The size effect of structure surfaces is different with different morphological surface. Generally, as the size increases, the roughness of structure surfaces increases and then decreases. There is positive size effect in small scale and negative size effect in large scale. (2) For a given structural surface, when the same size surfaces are selected from different locations of the structural planes, and the size effect characteristics are also different. (3) As the size of structure surfaces increases, the parameter $$\Delta D_{\max }^{SD}$$ Δ D max SD gradually decreases and tends to almost constant. The result of this study is a useful supplement to the comprehensive understanding of the size effect of structural surfaces roughness.

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Fractal Structure of Au Geochemical Field for Shuikoushan Orefield in Hunan Province, China and its Application to Mineralization

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1092-1093.1398 ◽

2015 ◽

Vol 1092-1093 ◽

pp. 1398-1401 ◽

Cited By ~ 1

Author(s):

Yan Shi Xie ◽

Jian Wen Yin ◽

Kai Xuan Tan ◽

Liang Chen ◽

Yang Hu ◽

...

Keyword(s):

Fractal Dimension ◽

Large Scale ◽

Fractal Structure ◽

Fractal Dimensions ◽

Hunan Province ◽

Small Scale ◽

Fractal Measure ◽

Mafic Magmatism ◽

Covering Method ◽

Polymetallic Ore

The fractal measure on Au geochemical field of Mawangtang and Xinmengshan in Shuikoushan Pb-Zn-Au polymetallic ore field, Hunan, China was achieved by projective covering method in this paper. The results show a bifractal relation for Au Geochemical field which includes a textural fractal dimension (D1) at small scale and a structural fractal dimension (D2) at large scale with average breakpoint 86.0m which may be look as the movement scale of ore-forming fluid. All of fractal dimensions were between 2 to 3, D1 was 2.0011 and D2 was 2.0001 at Mawangtang as well as D1 was 2.4466 and D2 was 2.0408 at Xinmengshan respectively. The fractal dimensions appear the textural fractal dimensions were larger than their structural fractal dimensions indicate that the evolution of ore-forming fluid more complex than background value of this ore field. And what’s more, the fractal values of Mawangtang were larger than Xinmengshan may result from the mineralization with the former not only control by the overthrust structure and fold the same as the latter but also had a closed relationship with the acid to mafic magmatism.

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A MODIFIED TWO-SCALE MICROWAVE SCATTERING MODEL FOR A GAUSSIAN-DISTRIBUTED CONDUCTING ROUGH SURFACE

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-3-2141-2018 ◽

2018 ◽

Vol XLII-3 ◽

pp. 2141-2146

Author(s):

F. Yu ◽

H. Wang ◽

Z. Y. Chen

Keyword(s):

Surface Roughness ◽

Rough Surface ◽

Large Scale ◽

Incident Angle ◽

Wavelet Packet ◽

Small Scale ◽

Backscattering Coefficient ◽

Microwave Scattering ◽

Scattering Model ◽

Scale Roughness

A modified two-scale microwave scattering model (MTSM) was presented to describe the scattering coefficient of natural rough surface in this paper. In the model, the surface roughness was assumed to be Gaussian so that the surface height z(x, y) can be split into large-scale and small-scale components relative to the electromagnetic wavelength by the wavelet packet transform. Then, the Kirchhoff Model (KM) and Small Perturbation Method (SPM) were used to estimate the backscattering coefficient of the large-scale and small-scale roughness respectively. Moreover, the ‘tilting effect’ caused by the slope of large-scale roughness should be corrected when we calculated the backscattering contribution of the small-scale roughness. Backscattering coefficient of the MTSM was the sum of backscattering contribution of both scale roughness surface. The MTSM was tested and validated by the advanced integral equation model (AIEM) for dielectric randomly rough surface, the results indicated that, the MTSM accuracy were in good agreement with AIEM when incident angle was less than 30&deg; (&theta;i&thinsp;&lt;30&deg;) and the surface roughness was small (ks&thinsp;=&thinsp;0.354).

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Some Observations on the Computational Sensitivity of Rotating Cavity Flows

Volume 7C: Heat Transfer ◽

10.1115/gt2020-16103 ◽

2020 ◽

Author(s):

Tom Hickling ◽

Li He

Keyword(s):

Heat Transfer ◽

Large Scale ◽

Internal Flow ◽

Systematic Investigation ◽

Small Scale ◽

Rotating Cavity ◽

Ekman Layers ◽

Inertial Wave ◽

Wall Flow ◽

Large Scale Flow

Abstract Heat transfer inside rotating cavities plays an important role in gas turbine engineering. Flows in both compressors and turbine internal flow cavities exhibit self-generated large-scale inertial wave structures, and buoyancy effects are often important. Across the open literature on the topic, there seems to be no clear consensus on what the most suitable modelling fidelity is — although it is a widely held opinion that URANS approaches are less suitable than LES, many authors have succeeded in getting reasonable heat transfer results with URANS. There is also little knowledge of the validity of hybrid URANS/LES type approaches (such as DES) when it comes to predicting the heat transfer in these flows, and furthermore, on the sensitivity of the flow model validity to local driving aerothermal mechanisms in different parts of the cavity. This paper presents the results of a systematic investigation of a rotating cavity with axial throughflow at a Grashof number of 3 × 109. It is found that, for the case investigated, the disk Ekman layers remain laminar. This causes the disk heat transfer to be relatively insensitive to the modelling fidelity used with URANS, DES, and LES giving similar results. The effect of the disk thermal boundary condition is also investigated — it is found to have a significant effect on the direction of the near-wall flow at high radii, despite the large-scale flow structure within the cavity remaining essentially unchanged. This feedback of the disk heat transfer to the near-disk aerodynamics implies that conjugate heat transfer computations of rotating cavities may be worth investigating. On the shroud, URANS fails to resolve the heat transfer enhancement from small-scale buoyancy driven streaks, whilst these are captured by LES. DES also captures these streaks, as the URANS layer within which they are located returns a very small eddy viscosity, and behaves in a similar manner to LES.

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Modeling surface-roughness/solar-ablation feedback: application to small-scale surface channels and crevasses of the Greenland ice sheet

Annals of Glaciology ◽

10.3189/172756411799096268 ◽

2011 ◽

Vol 52 (59) ◽

pp. 99-108 ◽

Cited By ~ 23

Author(s):

L. Maclagan Cathles ◽

Dorian S. Abbot ◽

Jeremy N. Bassis ◽

Douglas R. MacAyeal

Keyword(s):

Surface Roughness ◽

Solar Radiation ◽

Solar Energy ◽

Large Scale ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Ablation Rate ◽

Small Scale ◽

Universal Curve ◽

Roughness Effects

AbstractSurface roughness enhances the net ablation rate associated with direct solar radiation relative to smooth surfaces, because roughness allows solar energy reflected from one part of the surface to be absorbed by another part. In this study we examine the feedback between solar-radiation-driven ablation and growth of surface roughness on the Greenland ice sheet, using a numerical model of radiative transfer. Our experiments extend previous work by examining: (1) the effects of diurnal and seasonal variation of solar zenith angle and azimuth relative to incipient roughness features, (2) the evolution of roughness geometry in response to radiatively driven ablation and (3) the relative solar energy collection efficiencies of various roughness geometries and geographic locations and orientations. A notable result of this examination is that the time evolution of the aspect ratio of surface features under solar-driven ablation collapses onto a roughly universal curve that depends only on latitude, not the detailed shape of the feature. The total enhancement of surface melt relative to a smooth surface over a full ablation season varies with this ratio, and this dependence suggests a way to parameterize roughness effects in large-scale models that cannot treat individual roughness features. Overall, our model results suggest that surface roughness at the latitudes spanned by the Greenland ice sheet tends to dissipate as the ablation season progresses.

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Stochastic modeling of the oceanic mesoscale eddies

10.5194/egusphere-egu21-15010 ◽

2021 ◽

Author(s):

Long Li ◽

Bruno Deremble ◽

Noé Lahaye ◽

Etienne Mémin

Keyword(s):

Large Scale ◽

Mesoscale Eddy ◽

Low Frequency ◽

Stochastic Approach ◽

Coarse Grained ◽

Small Scale ◽

Oceanic Circulation ◽

Stochastic Representation ◽

Stochastic Framework ◽

Gyre Circulation

In this work, a stochastic representation [Bauer2020a, Bauer2020b] based on a physical transport principle is proposed to account for mesoscale eddy effects on the the large-scale oceanic circulation. This stochastic framework [M&#233;min2014] arises from a decomposition of the Lagrangian velocity into a time-smooth component and a highly oscillating noise term. One important characteristic of this random model is that it conserves the energy of any transported tracer. Such an energy-preserving representation has been successfully implemented in a well established multi-layered quasi-geostrophic dynamical core (http://www.q-gcm.org). The empirical spatial correlation of the small-scale noise is estimated from the eddy-resolving simulation data. In particular, a sub-grid correction drift has been introduced in the noise due to the bias ensuing from the coarse-grained procedure. This non intuitive term seems quite important in reproducing on a coarse mesh the meandering jet of the wind-driven double-gyre circulation. In addition, a new projection method has been proposed to constrain the noise living along the iso-surfaces of the vertical stratification. The resulting noise enables us to improve the intrinsic low-frequency variability of the large-scale current. From some statistical studies and energy transfers analysis, this improvement is well demonstrated.<ul><li>[Bauer2020a] W. Bauer, P. Chandramouli, B. Chapron, L. Li, and E. M&#233;min. Deciphering the role&#160;of small-scale inhomogeneity on geophysical flow structuration: a stochastic approach. Journal of Physical Oceanography, 50(4):983-1003, 2020a.&#160; &#160; &#160; &#160;</li> <li>[Bauer2020b] W. Bauer, P. Chandramouli, L. Li, and E. M&#233;min. Stochastic representation of mesoscale&#160;eddy effects in coarse-resolution barotropic models. Ocean Modelling, 151:101646 (2020b). &#160; &#160;</li> <li>[M&#233;min2014] E. M&#233;min. Fluid flow dynamics under location uncertainty. Geophysical & Astrophysical Fluid Dynamics, 108(2):119-146, 2014.&#160; &#160; &#160;</li> </ul>

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Large Scale Leach Testing of Dwpf Canister Sections

MRS Proceedings ◽

10.1557/proc-84-509 ◽

1986 ◽

Vol 84 ◽

Cited By ~ 4

Author(s):

Dennis F. Bickford ◽

Daniel J. Pellarin

Keyword(s):

Surface Roughness ◽

Large Scale ◽

Scale Up ◽

Test Method ◽

Waste Form ◽

Test Facility ◽

Small Scale ◽

Glass Product ◽

Leach Test ◽

Sampling Statistics

AbstractA Large-Scale Leach Test Facility (LSLTF) has been constructed at the U.S. Department of Energy's Savannah River Laboratory (SRL) to perform static leach tests on 24-inch (610 mm)-diameter canister sections cut from simulated (nonradioactive) waste forms cast under reference conditions. The equipment and test procedures are designed to closely correspond to MCC-l leach test criteria.Less than a factor of 3 increase in leachability results from combined scale-up, glass-cracking, leached surface area estimation, and surface roughness effects. This factor is dominated by surface roughness of saw cut surfaces. The factor is negligible when compared to the 200,000/1 ratio of glass sample masses.The MCC-l, and other small-scale leach tests have been valuable in determining the relative merits of alternative waste form compositions. However, the actual waste glass to be stored in repositories is subject to fracture, devitrification, and container/glass interactions, which are difficult to simulate on a laboratory scale. Large-scale leach tests integrate these and other possible waste form characteristics that are not represented in typical small samples.The facility, equipment, test method and results of one year leach test- ing are discussed. These results substantiate the applicability of small scale test data which precede this work, and the use of small scale tests to simulate leaching of the Defense Waste Processing Facility's borosilicate glass product. Exceptionally good sampling statistics make the large scale data particularly well suited for verification of models of leachability rates.

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Le synclinorium de l'aiguille de Morges et le style des deformations alpines du cristallin du Pelvoux

BSGF - Earth Sciences Bulletin ◽

10.2113/gssgfbull.s6-i.1-3.169 ◽

1951 ◽

Vol S6-I (1-3) ◽

pp. 169-183

Author(s):

Jean Vernet

Keyword(s):

Large Scale ◽

Sedimentary Cover ◽

Sedimentary Rocks ◽

Crystalline Rocks ◽

Small Scale ◽

Cumulus Cloud ◽

Mechanism Of Formation ◽

Crystalline Complex ◽

Alpine Orogeny ◽

Structural Surface

Abstract A study of the structural surface of the Pelvoux crystalline complex in the Morges synclinorium, southeast of Chapelle-en-Valgaudemar, in the Briancon region, France. This surface resembles that of a cumulus cloud in shape. It is concluded that during the Alpine orogeny the crystalline complex was deformed, on a large scale, as a semirigid, semiplastic mass, with faulting only on a small scale. The sedimentary cover, on the other hand, was subjected to strong tangential displacements, resulting in the piling up of thrust slices. The mechanism of formation of closed synclines, enlarging downwards and often enclosing pockets of sedimentary rocks entirely within the crystalline rocks, is not yet clear.

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Rapid and Non-Destructive Repair of Fused Silica with Cluster Damage by Magnetorheological Removing Method

Micromachines ◽

10.3390/mi12030274 ◽

2021 ◽

Vol 12 (3) ◽

pp. 274

Author(s):

Mingjie Deng ◽

Ci Song ◽

Feng Shi ◽

Yaofei Zhang ◽

Ye Tian ◽

...

Keyword(s):

Surface Roughness ◽

Large Scale ◽

Fused Silica ◽

Small Scale ◽

Damage Repair ◽

Laser Systems ◽

Computer Controlled Optical Surfacing ◽

Computer Controlled ◽

Non Destructive ◽

Small Scale Damage

The damage repair of fused silica based on the CO2 laser repair technique has been successfully applied in high-power laser systems in the controllable nuclear fusion field. However, this kind of repairing technique mainly focuses on large-scale laser damage with sizes larger than 200 μm, but ignores the influence of cluster small-scale damage with sizes smaller than 50 μm. In order to inhibit the growth of small-scale damage and further improve the effect of fused silica damage repair, this paper carried out a study on the repair of fused silica damage using the magnetorheological (MR) removing method. The feasibility of fused silica damage repairing was verified, and the evolution law of the number, morphology, and the surface roughness of small-scale damage were all analyzed. The results showed that the MR removing method was non-destructive compared to traditional repairing technologies. It not only effectively improved the whole damage repairing rate to more than 90%, but it also restored the optical properties and surface roughness of the damaged components in the repairing process. Based on the study of the MR removing repair law, a combined repairing process of 4 μm MR removal and 700 nm computer controlled optical surfacing (CCOS) removal is proposed. A typical fused silica element was experimentally repaired to verify the process parameters. The repairing rate of small-scale damage was up to 90.4%, and the surface roughness was restored to the level before repairing. The experimental results validate the effectiveness and feasibility of the combined repairing process. This work provides an effective method for the small-scale damage repairing of fused silica components.

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Toward Risk Assessment of Explosion Hazard: Experimental Determination of Flame Fractal Dimension

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.320.151 ◽

2011 ◽

Vol 320 ◽

pp. 151-155 ◽

Cited By ~ 1

Author(s):

Daisuke Takeda ◽

Woo Kyung Kim ◽

Yukari Wada ◽

Kazunori Kuwana ◽

Toshio Mogi ◽

...

Keyword(s):

Risk Assessment ◽

Fractal Dimension ◽

Large Scale ◽

Previous Method ◽

Small Scale ◽

Explosion Hazard ◽

Scale Experiment ◽

The Cost ◽

Explosion Experiment

Quantitative risk analysis is a method to evaluate risk and to identify areas for risk reduction. The final goal of our study is to propose an effective method for risk assessment of explosion hazard. To achieve the goal, a phenomenon that influences the consequences of explosion is first identified: self-turbulization and resulting acceleration of expanding flame during explosion. The fractal dimension is then identified as the key parameter that characterizes the phenomenon. Since the previous method to determine fractal dimension relies on large-scale explosion experiment, it has not been easy to determine fractal dimension. This paper demonstrates the possibility of determining fractal dimension by analyzing flame images of small-scale experiment, which might significantly reduce the cost of risk assessment of explosion hazard.

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Small-Scale Science to Large-Scale Profession

Contemporary Psychology ◽

10.1037/002246 ◽

2000 ◽

Vol 45 (4) ◽

pp. 396-398

Author(s):

Roger Smith

Keyword(s):

Large Scale ◽

Small Scale

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