scholarly journals Effect of An Image Resolution Change on the Effective Transport Coefficient of Heterogeneous Materials

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3757 ◽  
Author(s):  
Abimael Rodriguez ◽  
Romeli Barbosa ◽  
Abraham Rios ◽  
Jaime Ortegon ◽  
Beatriz Escobar ◽  
...  
Keyword(s):  
Transport Coefficient ◽  
Statistical Study ◽  
Image Resolution ◽  
Minimum Size ◽  
Image Size ◽  
Statistical Behavior ◽  
Effective Transport ◽  
Electrochemical Electrodes ◽  
Volume Method ◽  
Annealing Method

Electrochemical electrodes comprise multiple phenomena at different scales. Several works have tried to model such phenomena using statistical techniques. This paper proposes a novel process to work with reduced size images to reconstruct microstructures with the Simulated Annealing method. Later, using the Finite Volume Method, it is verified the effect of the image resolution on the effective transport coefficient (ETC). The method can be applied to synthetic images or images from the Scanning Electron Microscope. The first stage consists of obtaining the image of minimum size, which contains at least 98% of the statistical information of the original image, allowing an equivalent statistical study. The image size reduction was made by applying an iterative decimation over the image using the normalized coarseness to compare the amount of information contained at each step. Representative improvements, especially in processing time, are achieved by reducing the size of the reconstructed microstructures without affecting their statistical behavior. The process ends computing the conduction efficiency from the microstructures. The simulation results, obtained from two kinds of images from different materials, demonstrate the effectivity of the proposed approach. It is important to remark that the controlled decimation allows a reduction of the processor and memory use during the reconstruction and ETC computation of electrodes.

scholarly journals Numerical Simulation to Determine the Effect of Topological Entropy on the Effective Transport Coefficient of Unidirectional Composites

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 423
Author(s):  
Carlos Pacheco ◽  
Romeli Barbosa ◽  
Abimael Rodriguez ◽  
Gerko Oskam ◽  
Miguel Ruiz-Gómez ◽  
...  
Keyword(s):  
Topological Entropy ◽  
Transport Coefficient ◽  
Design Tool ◽  
Two Phase ◽  
Transport Efficiency ◽  
Sem Image ◽  
Statistical Reconstruction ◽  
Surface Fraction ◽  
Effective Transport ◽  
Volume Method

The influence of topological entropy (TS) on the effective transport coefficient (ETC) of a two-phase material is analyzed. The proposed methodology studies a system of aligned bars that evolves into a stochastic heterogeneous system. This proposal uses synthetic images generated by computational algorithms and experimental images from the scanning electron microscope (SEM). Microstructural variation is imposed for statistical reconstruction moments by simulated annealing (SA) and it is characterized through TS applied in Voronoi diagrams of the studied systems. On the other hand, ETC is determined numerically by the Finite Volume Method (FVM) and generalized by a transport efficiency of charge (ek). The results suggest that our approach can work as a design tool to improve the ETC in stochastic heterogeneous materials. The case studies show that ek decreases when TS increases to the point of stability of both variables. For example, for the 80% surface fraction, in the particulate system of diameter D = 1, ek = 50.81 ± 0.26% @ TS = 0.27 ± 0.002; when the system has an agglomerate distribution similar to a SEM image, ek = 45.69 ± 0.60% @ TS = 0.32 ± 0.002.

scholarly journals Speed Improvement in Image Stitching for Panoramic Dynamic Images during Minimally Invasive Surgery

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Dinh Thai Kim ◽  
Van Thang Nguyen ◽  
Ching-Hwa Cheng ◽  
Don-Gey Liu ◽  
Kai Che Jack Liu ◽  
...  
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Invasive Surgery ◽  
Region Of Interest ◽  
Original Method ◽  
Image Resolution ◽  
Image Stitching ◽  
Image Size ◽  
Performance Improvements ◽  
Physical Trauma

Minimally invasive surgery (MIS) minimizes the surgical incisions that need to be made and hence reduces the physical trauma involved during the surgical process. The ultimate goal is to reduce postoperative pain and blood loss as well as to limit the scarring area and hence accelerate recovery. It is therefore of great interest to both the surgeon and the patient. However, a major problem with MIS is that the field of vision of the surgeon is very narrow. We had previously developed and tested an MIS panoramic endoscope (MISPE) that provides the surgeon with a broader field of view. However, one issue with the MISPE was its low rate of video stitching. Therefore, in this paper, we propose using the region of interest in combination with the downsizing technique to improve the image-stitching performance of the MISPE. Experimental results confirm that, by using the proposed method, the image size can be increased by more than 160%, with the image resolution also improving. For instance, we could achieve performance improvements of 10× (CPU) and 23× (GPU) as compared to that of the original method.

Optimal Porosity of Fibrous Battings for Thermal Insulation

2007 ◽  
Author(s):  
Jintu Fan ◽  
Ning Du ◽  
Huijun Wu
Keyword(s):  
Simulated Annealing ◽  
Porous Materials ◽  
Thermal Insulation ◽  
Optimal Distribution ◽  
Fibrous Materials ◽  
Simulated Annealing Method ◽  
Thermal Insulating ◽  
Volume Method ◽  
Fiber Radius ◽  
Annealing Method

The porosity of fibrous porous materials is an important factor to the thermal insulating performance of the material. This paper considers both the optimal porosity of uniform fibrous battings and the optimal distribution of the porosity of non-uniform fibrous battings for thermal insulation. The former was determined by an approximate analytical solution and a numerical simulation by using Finite Volume Method, and the latter was studied by applying Simulated Annealing Method. The study showed that the optimal porosity of uniform fibrous porous materials is very much dependent on fiber emissivity, and fiber radius, but little influenced by the temperature difference of the boundaries. For non-uniform fibrous materials, there can be an optimal distribution of porosity, which can be predicted by applying the Simulated Annealing Method.

scholarly journals The Creation of an Experimental Data Set Containing Coronal Section Images of a Human Head

2021 ◽  
pp. 014556132198943
Author(s):  
Xiang-Dong Chen ◽  
Qiong-Jie Ma ◽  
Jun Wang ◽  
Yong-Sheng Zhou ◽  
Man-Ying Geng ◽  
...  
Keyword(s):  
Experimental Data ◽  
Digital Camera ◽  
Human Head ◽  
Image Resolution ◽  
Filling Material ◽  
Image Size ◽  
Data Set ◽  
Virtual Operation ◽  
Male Cadaver ◽  
Coronal Section

Objectives: The aim of the research is to create an experimental data set of coronal section images of a human head. Methods: The head of a 49-year-old male cadaver was scanned by computed tomography (CT), then perfused with a green filling material via the bilateral common carotid artery, before being frozen and embedded. The head was sectioned along the coronal plane by a computer-controlled 5520 engraving and milling machine, capable of either 0.03-mm or 0.06-mm interspacing. All images were captured with a Canon 5D-Mk III digital camera. Results: A total of 3854 section images were obtained, each with a resolution of 5760 × 3840 pixels. The number of section images at 0.03- and 0.06-mm interspacing were 1437 and 2417, respectively. All the images were stored in JPG and RAW formats. The image size of each RAW format was about 24.5 MB, whereas for JPG format, the equivalent size was about 5.9 MB. All the RAW and JPG images together occupied 117.35 GB of disk space. Conclusions: The interspacing of this data set section was thinner than those of any comparable studies, and the image resolution was higher, too. This data set was also the first to take coronal sections of the human head. The data set contains image information from the smallest structures within the human head and can satisfy the needs of future developments and applications, such as the virtual operation training systems for otolaryngology, ophthalmology, stomatology, and neurosurgery, and help develop medical teaching software and maps.

scholarly journals Comparison of Petrophysical Properties of Porous Rocks Using NMR, Micro-CT, and Fluid Flow Simulations

Geosciences ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 500
Author(s):  
Apoorv Jyoti ◽  
Ralf R. Haese
Keyword(s):  
Water Saturation ◽  
Image Resolution ◽  
Nuclear Magnetic Resonance Analysis ◽  
Ct Image ◽  
Petrophysical Properties ◽  
Micro Ct ◽  
Image Size ◽  
Flow Simulations ◽  
Transport Regime ◽  
Rock Types

Micro-computed tomography (micro-CT) is increasingly utilized to image the pore network and to derive petrophysical properties in combination with modelling software. The effect of micro-CT image resolution and size on the accuracy of the derived petrophysical properties is addressed in this study using a relatively homogenous sandstone and a heterogenous, highly porous bioclastic limestone. Standard laboratory procedures including NMR (nuclear magnetic resonance) analysis, micro-CT analysis at different image resolutions and sizes and pore-scale flow simulations were used to determine and compare petrophysical properties. NMR-derived pore-size distribution (PSD) was comparable to the micro-CT-derived PSD at a resolution of 7 µm for both the rock types. Porosity was higher using the water saturation method as compared to the NMR method in both rocks. The resolution did not show a significant effect on the porosity of the homogeneous sandstone, but porosity in the heterogeneous limestone varies depending on the location of the sub-sample. The transport regime in the sandstone was derived by simulations and changed with the resolution of the micro-CT image. The transport regime in the sandstone was advection-dominated at higher image resolution and diffusion-dominated when using a lower image resolution. In contrast, advection was the dominant transport regime for the limestone based on simulations using higher and lower image resolutions. Simulation-derived permeability for a 400 Voxel3 image at 7 µm resolution in the Berea sandstone matched laboratory results, although local heterogeneity within the rock plays an integral role in the permeability estimation within the sub-sampled images. The simulation-derived permeability was highly variable in the Mount Gambier limestone depending on the image size and resolution with the closest value to a laboratory result simulated with an image resolution of 2.5 µm and a size of 300 Voxel3. Overall, the study demonstrates the need to decide on micro-CT parameters depending on the type of petrophysical property of interest and the degree of heterogeneity within the rock types.

scholarly journals EFFECTS OF IMAGE SIZE AND SAMPLE AREAS ON COMPARISON OF CONTACT LENS SURFACES BASED ON FRACTAL DIMENSION

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Božica Bojović
Keyword(s):  
Fractal Dimension ◽  
Image Resolution ◽  
Image Size ◽  
Imaging Device ◽  
Sample Area ◽  
Fractal Properties ◽  
The One ◽  
Near Future ◽  
Selection Of ◽  
Made In

Methods used for calculation of fractal dimension demand large image resolution and adequate sample size, in terms of roughness threshold that defines spatial scope for rough surface fractal properties. Imaging device operators, on the one hand, recommend the image size and sample area based on experience and expertise, in order to minimize the imaging time. On the other hand, engineers make decisions based on their own requirements. To overcome these problems, in this paper we used ANOVA statistical approach (one-way and multi comparison) so as to establish significant image size and sample area. The conclusion made in this paper will enable decision guidelines on selection of parameters for new nanophotonic lenses imaging by scanning microscopes in near future.

scholarly journals Human Motion Posture Detection Algorithm Using Deep Reinforcement Learning

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Limin Qi ◽  
Yong Han
Keyword(s):  
Deep Learning ◽  
Reinforcement Learning ◽  
Capture Rate ◽  
Detection Algorithm ◽  
Human Motion ◽  
Contour Detection ◽  
Image Resolution ◽  
Detection Accuracy ◽  
Image Size ◽  
Learning Network

To address problems of serious loss of details and low detection definition in the traditional human motion posture detection algorithm, a human motion posture detection algorithm using deep reinforcement learning is proposed. Firstly, the perception ability of deep learning is used to match human motion feature points to obtain human motion posture features. Secondly, normalize the human motion image, take the color histogram distribution of human motion posture as the antigen, search the region close to the motion posture in the image, and take its candidate region as the antibody. By calculating the affinity between the antigen and the antibody, the feature extraction of human motion posture is realized. Finally, using the training characteristics of deep learning network and reinforcement learning network, the change information of human motion posture is obtained, and the design of human motion posture detection algorithm is realized. The results show that when the image resolution is 384 × 256 px, the motion pose contour detection accuracy of this algorithm is 87%. When the image size is 30 MB, the recognition time of this method is only 0.8 s. When the number of iterations is 500, the capture rate of human motion posture details can reach 98.5%. This shows that the proposed algorithm can improve the definition of human motion posture contour, improve the posture detailed capture rate, reduce the loss of detail, and have better effect and performance.

Effective Dielectric Function of Porous Silicon: the Transverse Component

1994 ◽  
Vol 358 ◽  
Author(s):  
J.E. Lugo ◽  
J.A. Del Río ◽  
J. Tagüeña-Martínez ◽  
J.A. Ochoa-Tapia
Keyword(s):  
Electrical Conductivity ◽  
Porous Media ◽  
Porous Silicon ◽  
Dielectric Function ◽  
Fluid Transport ◽  
Transverse Component ◽  
Axial Component ◽  
Effective Transport ◽  
Volume Method ◽  
Original Approach

ABSTRACTIn previous works we have obtained an expression for the effective electrical conductivity of a columnar model simulating porous silicon. We used the averaging volume method that has proven to be successful in treating fluid transport in porous media. With this method we can calculate the bulk and the surface contribution to an effective transport property. The axial component can be solved analytically, but in the xY plane the calculation can only be performed numerically. However there is a certain approximation called Chang's cell (valid for high porosities) where the transverse component is also analytical. The extension of our original approach to find the axial component of the effective dielectric function is relatively simple, but the transverse component calculation presents interesting features.

Statistical Study of the Rotation Effect of Am Stars

1976 ◽  
Vol 32 ◽  
pp. 675-683
Author(s):  
Keiichi Kodaira
Keyword(s):  
Statistical Study ◽  
Rotation Velocity ◽  
General View ◽  
Slow Rotation ◽  
Rotation Effect

SummaryExcess of [m1] index of Am stars, relative to normal stars, is statistically found to be correlated with rotation velocity; the coefficient is estimated at ∆׀m1׀ /∆V(km/sec) ˜ - 0.0007 among Am stars. This result supports the general view that slow rotation is essential for Am phenomena.

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