scholarly journals ANÁLISE 2D E 3D DA ESTABILIDADE DA BARRAGEM DE FUNDÃO

2020 ◽  
Vol 15 (2) ◽  
pp. 123-136
Author(s):  
Gilson de Farias Neves Gitirana Jr. ◽  
João Paulo Tavares Souza ◽  
Nícolas Rodrigues Moura
Keyword(s):  
Limit Equilibrium ◽  
Three Dimensional ◽  
Slope Instability ◽  
Two Dimensional ◽  
Slip Surfaces ◽  
Stable Conditions ◽  
General Limit ◽  
Critical Zones ◽  
2D And 3D ◽  
Drained Shear Strength

RESUMO: A falha da Barragem de Fundão, o maior desastre de seu tipo no mundo, foi estudada por Morgenstern et al. (2016) através de abordagens bidimensionais. A investigação realizada não apontou mecanismos de instabilidade de taludes como sendo as causas do desastre. No entanto, o formato complexo da face da barragem, com regiões côncavas e convexas, não foi considerado devido às limitações das ferramentas empregadas. Este trabalho apresenta análises bidimensionais (2D) e tridimensionais (3D), teoricamente mais rigorosas e adequadas para a geometria da barragem. As análises de estabilidade do maciço foram realizadas utilizando o Método Geral das Fatias e das Colunas (GLE), por meio do software SVSLOPE. Foram realizadas buscas por superfícies críticas 2D e 3D, ao longo de todas as zonas da estrutura. Considerando-se parâmetros de resistência drenada, observou-se que Fundão se encontraria em condições de elevada segurança, sendo o menor Fator de Segurança igual a 1,744. Valores próximos de 1,0 foram obtidos considerando rejeitos na condição não drenada, supostamente menos representativa das condições reais de campo. Os Fatores de Segurança 3D se mostraram muito próximos dos 2D, porém com variações significativas nas regiões côncava e convexa. Desta forma, conclui-se que o formato próximo à região do recuo exige maior atenção e análises 3D podem identificar as regiões críticas. ABSTRACT: The failure of the Fundão Dam, the largest disaster of its kind in the world, was studied by Morgenstern et al. (2016) using two-dimensional approaches. The carried out investigation did not point to mechanisms of slope instability as the causes of the disaster. However, the complex shape of the dam and its concave and convex regions were not originally considered due to limitations of the analysis tools employed. This paper presents two-dimensional (2D) and three-dimensional (3D) analyses that are more rigorous and well suited for the Fundão dam geometry. Slope stability analyses were accomplished using the General Limit Equilibrium Method of Slices and Columns (GLE) using the SVSLOPE software. Critical slip surfaces were searched in 2D and 3D, across the entire dam face. Drained shear strength parameters led to Factors of Safety that would indicate fairly stable conditions, with a lowest Factor of Safety of 1.744. Values close to 1.0 were obtained considering undrained conditions of the tailings, which are supposedly less representative of field conditions. The 3D factors of safety were very close to the 2D values, but with noticeably higher variations near the concave and convex regions. This leads to the conclusion that the dam shape near the setback region requires closer examination by means of 3D analyses that enable the identification of critical zones.

A general limit equilibrium model for three-dimensional slope stability analysis

1993 ◽  
Vol 30 (6) ◽  
pp. 905-919 ◽  
Author(s):  
L. Lam ◽  
D.G. Fredlund
Keyword(s):  
Stability Analysis ◽  
Case History ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Three Dimensional ◽  
Open Pit ◽  
Open Pit Mining ◽  
Two Dimensional ◽  
General Limit

A generalized model for three-dimensional analysis, using the method of columns, is presented. The model is an extension of the two-dimensional general limit equilibrium formulation. Intercolumn force functions of arbitrary shape can be specified to simulate various directions for the intercolumn resultant forces. A unique feature of the model involves the use of a geostatistical procedure (i.e., the Kriging technique) in modelling the geometry of the slope, the stratigraphy, the potential slip surface, and the pore-water pressure conditions. The technique simplifies the data-input procedure and expedites the column discretization and the factor of safety computations. The shape of the intercolumn force functions was investigated for several slope geometries using a three-dimensional finite element stress analysis. The significance of the intercolumn force functions in three-dimensional stability analyses was also studied. The model was utilized to study a case history involving an open-pit mining failure. The results indicate that the model is able to provide a more realistic simulation of the case history than was possible using a conventional two-dimensional model. Key words : stability analysis, general limit equilibrium, three-dimensional, method of columns, factor of safety.

scholarly journals Homogeneous 2D and 3D alignment of cardiomyocyte in dilated cardiomyopathy revealed by intravital heart imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kiyoshi Masuyama ◽  
Tomoaki Higo ◽  
Jong-Kook Lee ◽  
Ryohei Matsuura ◽  
Ian Jones ◽  
...  
Keyword(s):  
Heart Failure ◽  
Dilated Cardiomyopathy ◽  
Cardiac Dysfunction ◽  
Three Dimensional ◽  
Single Layer ◽  
Specific Pattern ◽  
Two Dimensional ◽  
Heart Imaging ◽  
Novel Method ◽  
2D And 3D

AbstractIn contrast to hypertrophic cardiomyopathy, there has been reported no specific pattern of cardiomyocyte array in dilated cardiomyopathy (DCM), partially because lack of alignment assessment in a three-dimensional (3D) manner. Here we have established a novel method to evaluate cardiomyocyte alignment in 3D using intravital heart imaging and demonstrated homogeneous alignment in DCM mice. Whilst cardiomyocytes of control mice changed their alignment by every layer in 3D and position twistedly even in a single layer, termed myocyte twist, cardiomyocytes of DCM mice aligned homogeneously both in two-dimensional (2D) and in 3D and lost myocyte twist. Manipulation of cultured cardiomyocyte toward homogeneously aligned increased their contractility, suggesting that homogeneous alignment in DCM mice is due to a sort of alignment remodelling as a way to compensate cardiac dysfunction. Our findings provide the first intravital evidence of cardiomyocyte alignment and will bring new insights into understanding the mechanism of heart failure.

scholarly journals Do 3D Face Images Capture Cues of Strength, Weight, and Height Better than 2D Face Images do?

2021 ◽  
Vol 7 (3) ◽  
pp. 209-219
Author(s):  
Iris J Holzleitner ◽  
Alex L Jones ◽  
Kieran J O’Shea ◽  
Rachel Cassar ◽  
Vanessa Fasolt ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Physical Characteristics ◽  
Two Dimensional ◽  
3D Images ◽  
3D Face ◽  
Face Images ◽  
Similar Accuracy ◽  
2D And 3D ◽  
2D Images ◽  
Better Than

Abstract Objectives A large literature exists investigating the extent to which physical characteristics (e.g., strength, weight, and height) can be accurately assessed from face images. While most of these studies have employed two-dimensional (2D) face images as stimuli, some recent studies have used three-dimensional (3D) face images because they may contain cues not visible in 2D face images. As equipment required for 3D face images is considerably more expensive than that required for 2D face images, we here investigated how perceptual ratings of physical characteristics from 2D and 3D face images compare. Methods We tested whether 3D face images capture cues of strength, weight, and height better than 2D face images do by directly comparing the accuracy of strength, weight, and height ratings of 182 2D and 3D face images taken simultaneously. Strength, height and weight were rated by 66, 59 and 52 raters respectively, who viewed both 2D and 3D images. Results In line with previous studies, we found that weight and height can be judged somewhat accurately from faces; contrary to previous research, we found that people were relatively inaccurate at assessing strength. We found no evidence that physical characteristics could be judged more accurately from 3D than 2D images. Conclusion Our results suggest physical characteristics are perceived with similar accuracy from 2D and 3D face images. They also suggest that the substantial costs associated with collecting 3D face scans may not be justified for research on the accuracy of facial judgments of physical characteristics.

Two-dimensional-Wilkins and real-time transesophageal three-dimensional scoring systems: Which one is preferred to mitral valve morphological assessment?

2021 ◽  
pp. 021849232110304
Author(s):  
Mehrnoush Toufan ◽  
Zahra Jabbary ◽  
Naser Khezerlou aghdam
Keyword(s):  
Mitral Valve ◽  
Transthoracic Echocardiography ◽  
Scoring System ◽  
Three Dimensional ◽  
Scoring Systems ◽  
Two Dimensional ◽  
Mitral Valve Area ◽  
2D And 3D ◽  
Morphological Assessment ◽  
Valve Area

Background To quantify valvular morphological assessment, some two-dimensional (2D) and three-dimensional (3D) scoring systems have been developed to target the patients for balloon mitral valvuloplasty; however, each scoring system has some potential limitations. To achieve the best scoring system with the most features and the least restrictions, it is necessary to check the degree of overlap of these systems. Also the factors related to the accuracy of these systems should be studied. We aimed to determine the correlation between the 2D Wilkins and real-time transesophageal three-dimensional (RT3D-TEE) scoring systems. Methods This cross-sectional study was performed on 156 patients with moderate to severe mitral stenosis who were candidates for percutaneous balloon valvuloplasty. To morphologic assessment of mitral valve, patients were examined by 2D-transthoracic echocardiography and RT3D-TEE techniques on the same day. Results A strong association was found between total Wilkins and total RT3D-TEE scores (r = 0.809, p < 0.001). The mean mitral valve area assessed by the 2D and 3D was 1.07 ± 0.25 and 1.03 ± 0.26, respectively, indicating a mean difference of 0.037 cm2 (p = 0.001). We found a strong correlation between the values of mitral valve area assessed by 2D and 3D techniques (r = 0.846, p < 0.001). Conclusion There is a high correlation between the two scoring systems in terms of evaluating dominant morphological features. Partially, mitral valve area overestimation in the 2D-transthoracic echocardiography and its inability to assess commissural involvement as well as its dependence on patient age were exceptions in this study.

scholarly journals Transformation Between 2D and 3D Covalent Organic Frameworks via Reversible [2+2] Cycloaddition

2020 ◽  
Author(s):  
Thaksen Jadhav ◽  
Yuan Fang ◽  
Cheng-Hao Liu ◽  
Afshin Dadvand ◽  
Ehsan Hamzehpoor ◽  
...  
Keyword(s):  
Band Structure ◽  
Absorption Edge ◽  
Room Temperature ◽  
Three Dimensional ◽  
Cross Linking ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
Doping Behavior ◽  
2D Polymers ◽  
2D And 3D

We report the first transformation between crystalline vinylene-linked two-dimensional (2D) polymers and crystalline cyclobutane-linked three-dimensional (3D) polymers. Specifically, absorption-edge irradiation of the 2D poly(arylenevinylene) covalent organic frameworks (COFs) results in topological [2+2] cycloaddition cross-linking the π-stacked layers in 3D COFs. The reaction is reversible and heating to 200°C leads to a cycloreversion while retaining the COF crystallinity. The resulting difference in connectivity is manifested in the change of mechanical and electronic properties, including exfoliation, blue-shifted UV-Vis absorption, altered luminescence, modified band structure and different acid-doping behavior. The Li-impregnated 2D and 3D COFs show a significant ion conductivity of 1.8×10<sup>−4</sup> S/cm and 3.5×10<sup>−5</sup> S/cm, respectively. Even higher room temperature proton conductivity of 1.7×10<sup>-2</sup> S/cm and 2.2×10<sup>-3</sup> S/cm was found for H<sub>2</sub>SO<sub>4</sub>-treated 2D and 3D COFs, respectively.

scholarly journals The Two-dimensional and Three-dimensional T2 Weighted Imaging-based Radiomic Signatures Selected for the Preoperative Discrimination of Ovarian Borderline Tumors and Epithelial Cancer.

2021 ◽  
Author(s):  
Xuefen Liu ◽  
Tianping Wang ◽  
Guofu Zhang ◽  
Keqin Hua ◽  
Hua Jiang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Operator Method ◽  
Two Dimensional ◽  
Borderline Tumors ◽  
Segmentation Methods ◽  
Highly Correlated ◽  
Selection Operator ◽  
2D And 3D ◽  
Testing Group ◽  
Segmentation Models

Abstract Background: Accurate discrimination between ovarian borderline tumors (BOTs) and malignancies with imaging play an important role in management.Purpose: To evaluate the ability of T2-weighted imaging (T2WI)-based radiomics to discriminate ovarian borderline tumors (BOTs) from malignancies based on two-dimensional (2D) and three-dimensional (3D) lesion segmentation methods.Methods: A total of 95 patients with pathologically proven ovarian BOTs and 101 patients with malignancies were retrospectively included in this study. We evaluated the diagnostic performance of the signatures derived from T2WI-based radiomics in their ability to differentiate between BOTs and malignancies and compared the performance differences in the 2D and 3D segmentation models. The least absolute shrinkage and selection operator method (LASSO) was used for radiomics feature selection and machine learning processing.Results: The radiomics score between BOTs and malignancies in four types of selected T2WI-based radiomics models differed significantly at the statistical level (p < 0.0001). For the classification between BOTs and malignant masses, the 2D and 3D coronal T2WI-based radiomics models yielded accuracy values of 0.79 and 0.83 in the testing group, respectively; the 2D and 3D sagittal fat-suppressed (fs) T2WI-based radiomics models yielded an accuracy of 0.78 and 0.99, respectively.Conclusion: Our results suggest that T2WI-based radiomic features were highly correlated with ovarian tumor subtype classification. 3D-sagittal MRI radiomics features may help clinicians differentiate ovarian BOTs from malignancies with high accuracy (ACC).

Study on Stability of High Embankments on Rock Slope under Complicated Stress Conditions

2011 ◽  
Vol 368-373 ◽  
pp. 1642-1648
Author(s):  
Gui Ling Ding
Keyword(s):  
Finite Element ◽  
Slip Surface ◽  
Three Dimensional ◽  
Slope Instability ◽  
Instability Criterion ◽  
Two Dimensional ◽  
Study Results ◽  
Geological Conditions ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Three-dimensional finite element analysis should be used in stability analysis of slope because it can overcome the short advantages of two-dimensional finite element and can simulate the complex topographic and geological conditions. Based on the large-scale triaxial shear test, the modified Duncan-Chang model is established. Based on strength reduction elasto-plastic finite element, stability of high fill embankment was studied with three-dimensional finite element method considering the complex terrain conditions. Study results suggest that plastic strain and displacement mutant of slip surface node can be a sign of slope instability as a whole. At the same time calculation of three-dimensional finite element also does not converge. Therefore, it can be slope instability criterion calculate whether the finite element static analysis converges or not. On the other hand, stability safety factor of high fill embankment under three-dimensional conditions is larger than that of two-dimensional conditions, which shows that boundary conditions of high fill embankment enhance its stability.

scholarly journals The Role of 2D and 3D Echo in Mitral Stenosis

2021 ◽  
Vol 8 (12) ◽  
pp. 171
Author(s):  
Juan Manuel Monteagudo Ruiz ◽  
José Luis Zamorano Gómez
Keyword(s):  
Heart Valve ◽  
Transthoracic Echocardiography ◽  
Mitral Stenosis ◽  
Imaging Modality ◽  
Three Dimensional ◽  
Heart Valve Disease ◽  
Two Dimensional ◽  
3D Echo ◽  
2D And 3D

Mitral stenosis is an important cause of heart valve disease globally. Echocardiography is the main imaging modality used to diagnose and assess the severity and hemodynamic consequences of mitral stenosis as well as valve morphology. Transthoracic echocardiography (TTE) is sufficient for the management of most patients. The focus of this review is the role of current two-dimensional (2D) and three-dimensional (3D) echocardiographic imaging for the evaluation of mitral stenosis.

scholarly journals Impact of Left Atrial Volume Index on Discrepancy in Mitral Valve Area Assessed by Two-Dimensional Planimetry and Three-Dimensional Multi-Planar Reconstruction Technique

2021 ◽  
Keyword(s):  
Left Atrial ◽  
Three Dimensional ◽  
Left Atrial Volume ◽  
Volume Index ◽  
Two Dimensional ◽  
Atrial Volume ◽  
Left Atrial Volume Index ◽  
Mitral Valve Area ◽  
2D And 3D ◽  
Valve Area

Background: Mitral valve area (MVA) is technically measured using both two-dimensional (2D) planimetry and three dimensional multi planar reconstruction (3D-MPR) techniques; however, studies have always overestimated MVA using the former method. Objectives: This study aimed to assess the correlation between MVA assessed by 2D and 3D techniques and the impact of left atrial volume index (LAVI) on the discrepancy between MVA assessed by two echocardiography techniques. Methods: The data of 75 patients with moderate to severe mitral stenosis assessed by both 2D planimetry and 3D-MPR techniques were retrospectively reviewed. Clinical and echocardiographic variables were evaluated. Left atrial (LA) volume was determined using biplane area-length method. Results: The mean MVA assessed by the 2D and 3D techniques was 1.03±0.24 cm2 and 0.99±0.25 cm2 with a mean discrepancy of 0.04±0.15 cm2, respectively. A strong association was observed between the MVA values assessed by 2D planimetry and 3D-MPR methods (r coefficient = 0.817, P<0.001) indicating a slight discrepancy between the two techniques in assessing MVA measure. The pointed discrepancy was affected by none of the baseline characteristics and LAVI value. There was an adverse association between LAVI value and MVA measured by both 2D planimetry (r coefficient = -0.291, P= 0.011) and 3D-MPR (r coefficient=-0.260, P=0.024). Conclusion: In contrast to the left atrial dimension, the discrepancy in MVA values assessed by 2D planimetry and 3D-MPR is not influenced by LAVI adjusted for baseline parameters.

Sign in / Sign up

Export Citation Format

Share Document