Magnetic models of crystalline terrane: Accounting for the effect of topography

Geophysics ◽  
1983 ◽  
Vol 48 (11) ◽  
pp. 1551-1557 ◽  
Author(s):  
Richard J. Blakely ◽  
V. J. S. Grauch
Keyword(s):  
Numerical Technique ◽  
Volcanic Rocks ◽  
Three Dimensional ◽  
Correlation Coefficients ◽  
High Amplitude ◽  
Cascade Range ◽  
Aeromagnetic Survey ◽  
Contour Map ◽  
Topographic Features ◽  
Geologic Interpretation

Igneous rocks commonly have large magnetic susceptibilities so that high topographic relief in crystalline terrane can produce significant anomalies in aeromagnetic surveys. Topographic anomalies are particularly significant in relatively undeformed volcanic terrane because young volcanic rocks generally have large natural remanent magnetizations as well as large susceptibilities. These anomalies commonly appear in aeromagnetic surveys as a complex pattern of high‐amplitude, short‐wavelength magnetic features that tend to obscure anomalies caused by deeper geologic sources. We have facilitated geologic interpretation of an aeromagnetic survey of the Oregon Cascade Range by calculating the magnetic field caused by a three‐dimensional (3-D) topographic model. Maps of the calculated field are compared with observed aeromagnetic data both visually and with a numerical technique that produces a contour map of correlation coefficients for the model. These comparisons allow quick recognition of anomalies caused by normally or reversely magnetized topographic features and, more importantly, identification of anomalies caused by geologic features not obviously caused by the topography.

scholarly journals The patellofemoral morphology and the normal predicted value of tibial tuberosity-trochlear groove distance in the Chinese population

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zhe Li ◽  
Guanzhi Liu ◽  
Run Tian ◽  
Ning Kong ◽  
Yue Li ◽  
...  
Keyword(s):  
Individual Differences ◽  
Chinese Population ◽  
Pearson Correlation ◽  
Three Dimensional ◽  
Correlation Coefficients ◽  
Tibial Tuberosity ◽  
Trochlear Groove ◽  
Lasso Regression ◽  
Cross Sectional ◽  
Anterior Posterior

Abstract Background Our objective was to obtain normal patellofemoral measurements to analyse sex and individual differences. In addition, the absolute values and indices of tibial tuberosity-trochlear groove (TT-TG) distances are still controversial in clinical application. A better method to enable precise prediction is still needed. Methods Seventy-eight knees of 78 participants without knee pathologies were included in this cross-sectional study. A CT scan was conducted for all participants and three-dimensional knee models were constructed using Mimics and SolidWorks software. We measured and analysed 19 parameters including the TT-TG distance and dimensions and shapes of the patella, femur, tibia, and trochlea. LASSO regression was used to predict the normal TT-TG distances. Results The dimensional parameters, TT-TG distance, and femoral aspect ratio of the men were significantly larger than those of women (all p values < 0.05). However, after controlling for the bias from age, height, and weight, there were no significant differences in TT-TG distances and anterior-posterior dimensions between the sexes (all p values > 0.05). The Pearson correlation coefficients between the anterior femoral offset and other indexes were consistently below 0.3, indicating no relationship or a weak relationship. Similar results were observed for the sulcus angle and the Wiberg index. Using LASSO regression, we obtained four parameters to predict the TT-TG distance (R2 = 0.5612, p < 0.01) to achieve the optimal accuracy and convenience. Conclusions Normative data of patellofemoral morphology were provided for the Chinese population. The anterior-posterior dimensions of the women were thicker than those of men for the same medial-lateral dimensions. More attention should be paid to not only sex differences but also individual differences, especially the anterior condyle and trochlea. In addition, this study provided a new method to predict TT-TG distances accurately.

scholarly journals Automatic 3D dense phenotyping provides reliable and accurate shape quantification of the human mandible

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pieter-Jan Verhelst ◽  
H. Matthews ◽  
L. Verstraete ◽  
F. Van der Cruyssen ◽  
D. Mulier ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Intraclass Correlation ◽  
Three Dimensional ◽  
Correlation Coefficients ◽  
Surface Registration ◽  
Anatomical Landmarks ◽  
Centroid Size ◽  
Intraclass Correlation Coefficients ◽  
Total Variability ◽  
Automatic Phenotyping

AbstractAutomatic craniomaxillofacial (CMF) three dimensional (3D) dense phenotyping promises quantification of the complete CMF shape compared to the limiting use of sparse landmarks in classical phenotyping. This study assesses the accuracy and reliability of this new approach on the human mandible. Classic and automatic phenotyping techniques were applied on 30 unaltered and 20 operated human mandibles. Seven observers indicated 26 anatomical landmarks on each mandible three times. All mandibles were subjected to three rounds of automatic phenotyping using Meshmonk. The toolbox performed non-rigid surface registration of a template mandibular mesh consisting of 17,415 quasi landmarks on each target mandible and the quasi landmarks corresponding to the 26 anatomical locations of interest were identified. Repeated-measures reliability was assessed using root mean square (RMS) distances of repeated landmark indications to their centroid. Automatic phenotyping showed very low RMS distances confirming excellent repeated-measures reliability. The average Euclidean distance between manual and corresponding automatic landmarks was 1.40 mm for the unaltered and 1.76 mm for the operated sample. Centroid sizes from the automatic and manual shape configurations were highly similar with intraclass correlation coefficients (ICC) of > 0.99. Reproducibility coefficients for centroid size were < 2 mm, accounting for < 1% of the total variability of the centroid size of the mandibles in this sample. ICC’s for the multivariate set of 325 interlandmark distances were all > 0.90 indicating again high similarity between shapes quantified by classic or automatic phenotyping. Combined, these findings established high accuracy and repeated-measures reliability of the automatic approach. 3D dense CMF phenotyping of the human mandible using the Meshmonk toolbox introduces a novel improvement in quantifying CMF shape.

Energetics of Barotropic and Baroclinic Tides in the Monterey Bay Area

2012 ◽  
Vol 42 (2) ◽  
pp. 272-290 ◽  
Author(s):  
Dujuan Kang ◽  
Oliver Fringer
Keyword(s):  
Energy Flux ◽  
Three Dimensional ◽  
Internal Tide ◽  
Submarine Canyon ◽  
Tidal Energy ◽  
Energy Partitioning ◽  
Navier Stokes ◽  
Monterey Bay ◽  
Topographic Features ◽  
Bay Area

Abstract A detailed energy analysis of the barotropic and baroclinic M2 tides in the Monterey Bay area is performed. The authors first derive a theoretical framework for analyzing internal tide energetics based on the complete form of the barotropic and baroclinic energy equations, which include the full nonlinear and nonhydrostatic energy flux contributions as well as an improved evaluation of the available potential energy. This approach is implemented in the Stanford Unstructured Nonhydrostatic Terrain-Following Adaptive Navier–Stokes Simulator (SUNTANS). Results from three-dimensional, high-resolution SUNTANS simulations are analyzed to estimate the tidal energy partitioning among generation, radiation, and dissipation. A 200 km × 230 km domain including all typical topographic features in this region is used to represent the Monterey Bay area. Of the 152-MW energy lost from the barotropic tide, approximately 133 MW (88%) is converted into baroclinic energy through internal tide generation, and 42% (56 MW) of this baroclinic energy radiates away into the open ocean. The tidal energy partitioning depends greatly on the topographic features. The Davidson Seamount is most efficient at baroclinic energy generation and radiation, whereas the Monterey Submarine Canyon acts as an energy sink. Energy flux contributions from nonlinear and nonhydrostatic effects are also examined. In the Monterey Bay area, the nonlinear and nonhydrostatic contributions are quite small. Moreover, the authors investigate the character of internal tide generation and find that in the Monterey Bay area the generated baroclinic tides are mainly linear and in the form of internal tidal beams. Comparison of the modeled tidal conversion to previous theoretical estimates shows that they are consistent with one another.

Key Technologies Research on Color Contour Map of 3D Injection Molding Simulation Results

2012 ◽  
Vol 217-219 ◽  
pp. 1998-2001
Author(s):  
Tie Geng ◽  
Qing Hai Ren ◽  
Wei Qing Tu ◽  
Dan Dan Liu
Keyword(s):  
Injection Molding ◽  
Color Image ◽  
Three Dimensional ◽  
Physical Field ◽  
Contour Map ◽  
Image Rendering ◽  
Color Range ◽  
Key Technologies ◽  
Injection Molding Simulation ◽  
Simulation Results

According to the color contour map of the 3D injection molding simulation results, the commonly used color contour map drawing algorithm was researched, and a three-dimensional color image rendering algorithm which based on the "physical field values and color range mapping" was given too. And the key technologies of the algorithm which was used to draw 3D color contour map were introduced in detail. In the end, an example was given.

Preliminary results of numerical simulation of submarine landslide-generated waves

2021 ◽  
Author(s):  
Ramtin Sabeti ◽  
Mohammad Heidarzadeh
Keyword(s):  
Numerical Simulation ◽  
Numerical Modelling ◽  
Numerical Solutions ◽  
Numerical Technique ◽  
Source Region ◽  
Three Dimensional ◽  
Terminal Velocity ◽  
Sensitivity Analyses ◽  
Physical Experiments ◽  
Set Up

&lt;p&gt;Landslide-generated waves have been major threats to coastal areas and have led to destruction and casualties. Their importance is undisputed, most recently demonstrated by the 2018 Anak Krakatau tsunami, causing several hundred fatalities. The accurate prediction of the maximum initial amplitude of landslide waves (&lt;em&gt;&amp;#951;&lt;sub&gt;max&lt;/sub&gt;&lt;/em&gt;) around the source region is a vital hazard indicator for coastal impact assessment. Laboratory experiments, analytical solutions and numerical modelling are three major methods to investigate the (&lt;em&gt;&amp;#951;&lt;sub&gt;max&lt;/sub&gt;&lt;/em&gt;). However, the numerical modelling approach provides a more flexible and cost- and time-efficient tool. This research presents a numerical simulation of tsunamis due to rigid landslides with consideration of submerged conditions. In particular, this simulation focuses on studying the effect of landslide parameters on &lt;em&gt;&amp;#951;&lt;sub&gt;max&lt;/sub&gt;.&lt;/em&gt; Results of simulations are compared with our conducted physical experiments at the Brunel University London (UK) to validate the numerical model.&lt;/p&gt;&lt;p&gt;We employ the fully three-dimensional computational fluid dynamics package, FLOW-3D Hydro for modelling the landslide-generated waves. This software benefit from the Volume of Fluid Method (VOF) as the numerical technique for tracking and locating the free surface. The geometry of the simulation is set up according to the wave tank of physical experiments (i.e. 0.26 m wide, 0.50 m deep and 4.0 m). In order to calibrate the simulation model based on the laboratory measurements, the friction coefficient between solid block and incline is changed to 0.41; likewise, the terminal velocity of the landslide is set to 0.87 m/s. Good agreement between the numerical solutions and the experimental results is found. Sensitivity analyses of landslide parameters (e.g. slide volume, water depth, etc.) on &lt;em&gt;&amp;#951;&lt;sub&gt;max &lt;/sub&gt;&lt;/em&gt;are performed. Dimensionless parameters are employed to study the sensitivity of the initial landslide waves to various landslide parameters.&lt;/p&gt;

Three-Dimensional Study of Fatigue Crack Growth in a Rotating Disc

2013 ◽  
Vol 3 (2) ◽  
pp. 45-62
Author(s):  
Eskandari Hadi ◽  
Nami Mohammad Rahim
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Front ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Crack Orientation ◽  
Rotating Disc ◽  
Mesh Density ◽  
Three Dimensional Finite Element

The problem of fatigue-crack-growth in a rotating disc at different crack orientation angles is studied by using an automated numerical technique, which calculates the stress intensity factors on the crack front through the three-dimensional finite element method. Paris law is used to develop the fatigue shape of initially semi-elliptical surface crack. Because of needs for the higher mesh density and accuracy near the crack, the sub-modeling technique is used in the analysis. The distribution of SIF’s along the crack front at each step of growth is studied and the effect of crack orientation on the rate of crack-growth is investigated. The calculated SIF’s are reasonable and could be used to predict the probable crack growth rates in fracture mechanics analysis and can help engineers to consider in their designing and to prevent any unwanted failure of such components.

Numerical Simulation Study on the Asymmetric Structures of Oscillatory Flow Field in a Baffled Tube Reactor

2004 ◽  
Author(s):  
Yong-Wen Wu ◽  
Jia Wu
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flows ◽  
Oscillatory Flow ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Structured Grid ◽  
Tube Reactor ◽  
Oscillating Boundary ◽  
The Asymmetry ◽  
Laminar And Turbulent Flows

The oscillatory flow in a baffled tube reactor provides a significant enhancement of radial transfer of momentum, heat and mass and a good control of axial back mixing at a wide range of net flow rate. But little has been known about reliable details of the three-dimensional structure of flow field in this kind of flow because most published studies in the area were based on the two-dimensional simulation techniques. This paper implemented a three-dimensional numerical simulation study on the asymmetry of flow pattern in the baffled tube reactor which was observed experimentally. A systematic study by numerical simulation was carried out which covered a range of oscillatory Reynolds number (Reo) from 100 to 5,000 and employed models respectively for laminar and turbulent flows. It was found in the simulation that under symmetric boundary conditions the transition from axially symmetric flow to asymmetric one depended on the numerical technique employed in simulation. With a structured grid frame the transition occurred at Reo much greater than that with an unstructured grid frame, for both laminar and turbulent flows. It is not rational that the onset of the transition changes with the accuracy of numerical technique. Based on the simulation results, it was postulated that the asymmetry appeared in simulations with symmetric boundary conditions might result from the accumulation of calculation errors but the asymmetry observed in experiments might result from the slight asymmetry of geometry which exists inevitably in any experiment apparatus. To explore the influence of the slight asymmetry of geometry, the effect of the eccentricity of baffles and the declination of oscillating boundary were studied by use of the finite volume method with a structured grid and adaptive time steps. The simulation result showed that both the eccentricity of baffles and the declination of oscillating boundary have obvious influence on the asymmetry of flow patterns for laminar and turbulent flow. More details were discussed in the paper.

A series solution and numerical technique for wave diffraction by a three-dimensional canyon

Wave Motion ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 129-142 ◽  
Author(s):  
Wen-I Liao ◽  
Tsung-Jen Teng ◽  
Chau-Shioung Yeh
Keyword(s):  
Wave Diffraction ◽  
Series Solution ◽  
Numerical Technique ◽  
Three Dimensional
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