MULTISPECTRAL ELECTROMAGNETIC EXPLORATION FOR SULFIDES

Geophysics ◽  
1974 ◽  
Vol 39 (5) ◽  
pp. 666-682 ◽  
Author(s):  
S. H. Ward ◽  
D. F. Pridmore ◽  
L. Rijo ◽  
W. E. Glenn
Keyword(s):  
Tilt Angle ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Major Axis ◽  
Test Site ◽  
Electromagnetic System ◽  
Plane Normal ◽  
Plane Passing ◽  
Comparison Of The Results ◽  
Phase Sensitive Detector

A 14 frequency electromagnetic system has been developed and applied to continuous sounding‐profiling over the two sulfide deposits of the Cavendish Test Site in Ontario, Canada. The tilt of the major axis, tilt angle, and the ratio of minor to major axis, ellipticity, of the ellipse of magnetic field polarization are measured over the frequency range 10.5 hz to 86,016 hz. A dual coil receiver employing a phase‐sensitive detector has been used to measure tilt angle and ellipticity with three transmitter configurations along a single traverse line of the Cavendish test site. These different transmitting coil configurations are referred to as horizontal coil, vertical axial coil, and vertical rotating coil. In the horizontal coil configuration, tilt angle and ellipticity are measured in the vertical plane passing through the axis of a horizontal transmitting coil. In the vertical axial coil configuration, tilt angle and ellipticity are measured in the vertical plane which passes through the axis of a vertical transmitting coil; the axis of the transmitting coil is oriented normal to the strike of the subsurface conductivity inhomogeneity. Finally, in the vertical rotating coil configuration, the transmitting coil is located along strike from the traverse over the conductivity inhomogeneity and rotated to contain each point of observation in turn; measurements of tilt angle and ellipticity are made in a vertical plane normal to the plane of the transmitting coil. The limitations of single‐body interpretation schemes are illustrated by the data. Recourse to calculation of scattering by two‐ and three‐dimensional complex environments will be required to provide any sort of full interpretation of these data from one simple Precambrian geologic setting. A comparison of the results for the three transmitting coil configurations indicates that the vertical axial coil configuration is least sensitive to overburden and host rock, while adequately responsive to concentrated and disseminated sulfides.

A three-dimensional computation of the force and torque on an ellipsoid settling slowly through a viscoelastic fluid

1995 ◽  
Vol 283 ◽  
pp. 1-16 ◽  
Author(s):  
J. Feng Feng ◽  
D. D. Joseph ◽  
R. Glowinski ◽  
T. W. Pan
Keyword(s):  
Reynolds Number ◽  
Viscoelastic Fluid ◽  
Tilt Angle ◽  
Three Dimensional ◽  
Major Axis ◽  
Weissenberg Number ◽  
Second Order ◽  
The Body ◽  
Fall Velocity ◽  
Elasticity Number

The orientation of an ellipsoid falling in a viscoelastic fluid is studied by methods of perturbation theory. For small fall velocity, the fluid's rheology is described by a second-order fluid model. The solution of the problem can be expressed by a dual expansion in two small parameters: the Reynolds number representing the inertial effect and the Weissenberg number representing the effect of the non-Newtonian stress. Then the original problem is split into three canonical problems: the zeroth-order Stokes problem for a translating ellipsoid and two first-order problems, one for inertia and one for second-order rheology. A Stokes operator is inverted in each of the three cases. The problems are solved numerically on a three-dimensional domain by a finite element method with fictitious domains, and the force and torque on the body are evaluated. The results show that the signs of the perturbation pressure and velocity around the particle for inertia are reversed by viscoelasticity. The torques are also of opposite sign: inertia turns the major axis of the ellipsoid perpendicular to the fall direction; normal stresses turn the major axis parallel to the fall. The competition of these two effects gives rise to an equilibrium tilt angle between 0° and 90° which the settling ellipsoid would eventually assume. The equilibrium tilt angle is a function of the elasticity number, which is the ratio of the Weissenberg number and the Reynolds number. Since this ratio is independent of the fall velocity, the perturbation results do not explain the sudden turning of a long body which occurs when a critical fall velocity is exceeded. This is not surprising because the theory is valid only for slow sedimentation. However, the results do seem to agree qualitatively with ‘shape tilting’ observed at low fall velocities.

Location of the Centre of Resistance for the Nasomaxillary Complex Studied in a Three-Dimensional Finite Element Model

1995 ◽  
Vol 22 (3) ◽  
pp. 227-232 ◽  
Author(s):  
Kazuo Tanne ◽  
Susumu Matsubara ◽  
Mamoru Sakuda
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Element Model ◽  
Occlusal Plane ◽  
Dimensional Finite Element ◽  
Plane Passing ◽  
Three Dimensional Finite Element

The purpose of this study was to investigate the location of the centre of resistance (CRe) for the nasomaxillary complex by the use of finite element analysis. A three-dimensional finite element model of the craniofacial complex, consisting of 2918 nodes and 1776 elements, was used for displacement analyses. Anteriorly and inferiorly directed forces of 9·8 N were applied at five different levels, parallel and perpendicular to the functional occlusal plane, respectively. For each loading condition, horizontal and vertical displacements of eight anatomic points in the complex and on the maxillary dentition were analysed. The complex exhibited an almost translatory displacement of approximately 1·0 µm in the forward direction when the horizontal force was applied at a point on the horizontal plane, passing through the superior ridge of the pterygomaxillary fissure, whereas the complex experienced clockwise or counter clockwise rotation when the forces were applied at the remaining levels. Furthermore, the downward forces produced anteriorly upward, or posteriorly upward rotation. However, the force applied at a point on the vertical plane passing through the posterior wall of the pterygomaxillary fissure, produced almost equal displacements of approximately 6·0 µm in an inferior direction for all the anatomic points. It is suggested that CRe of the nasomaxillary complex is located on the posterosuperior ridge of the pterygomaxillary fissure, registered on the median sagittal plane.

Three-dimensional flow due to a microcantilever oscillating near a wall: an unsteady slender-body analysis

2006 ◽  
Vol 462 (2067) ◽  
pp. 913-933 ◽  
Author(s):  
R.J Clarke ◽  
O.E Jensen ◽  
J Billingham ◽  
P.M Williams
Keyword(s):  
Three Dimensional ◽  
Vertical Plane ◽  
Circular Cross Section ◽  
Slender Body ◽  
Order Effects ◽  
End Effects ◽  
Dimensional Flow ◽  
Plane Normal ◽  
Two Dimensional Flow ◽  
Resistive Force Theory

We compute the drag on a slender rigid cylinder, of uniform circular cross-section, oscillating in a viscous fluid at small amplitude near a horizontal wall. The cylinder's axis lies at an angle α to the horizontal and the cylinder oscillates in a vertical plane normal to either the wall or its own axis. The flow is described using an unsteady slender-body approximation, which we treat both numerically and using an iterative scheme that extends resistive-force theory to account for the leading-order effects of unsteady inertia and the wall. When α is small, two independent screening mechanisms are identified which suppress end-effects and produce approximately two-dimensional flow along the majority of the cylinder; however, three-dimensional effects influence the drag at larger tilt angles.

scholarly journals TOPOGRAPHIC CHANGES IN THE SURF ZONE PROFILE

1966 ◽  
Vol 1 (10) ◽  
pp. 30 ◽  
Author(s):  
Choule J. Sonu ◽  
Richard J. Russell
Keyword(s):  
North Carolina ◽  
Surf Zone ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Normal Wave ◽  
Field Investigation ◽  
Dimensional Approach ◽  
Outer Banks ◽  
Plane Normal ◽  
The Waves

The conventional method of dealing with relationships between wave action and topographic response on a beach is to reduce the problem to a two-dimensional scheme that regards basic processes as taking place in a vertical plane normal to the shoreline. This scheme is valid only if the waves arrive at right angles to the shore and the nearshore contours are reasonably straight and parallel the beach. As these conditions are not realized in many cases another analytical method is necessary - one that recognizes effects of other than normal wave arrival and systematic patterns of diversification in nearshore topography. This study, based on a long period of field investigation on the Outer Banks, North Carolina, examines a three-dimensional approach. Observations from a long pier were used to explain nearshore topographic diversification and resulted in conclusions that were confirmed by subsequent field observation.

Reconstruction of Objects from their Projections Using Orthogonal Functions

1973 ◽  
Vol 31 ◽  
pp. 268-269
Author(s):  
Elrnar Zeitler
Keyword(s):  
Unit Area ◽  
Three Dimensional ◽  
One Dimension ◽  
Spatial Density ◽  
Dimensional Representation ◽  
Orthogonal Functions ◽  
Object A ◽  
Plane Normal ◽  
Dimensional Object ◽  
Spatial Density Distribution

Considering any finite three-dimensional object, a “projection” is here defined as a two-dimensional representation of the object's mass per unit area on a plane normal to a given projection axis, here taken as they-axis. Since the object can be seen as being built from parallel, thin slices, the relation between object structure and its projection can be reduced by one dimension. It is assumed that an electron microscope equipped with a tilting stage records the projectionWhere the object has a spatial density distribution p(r,ϕ) within a limiting radius taken to be unity, and the stage is tilted by an angle 9 with respect to the x-axis of the recording plane.

Methods for three-dimensional reconstruction of cellular components within a thick section

1986 ◽  
Vol 44 ◽  
pp. 18-21
Author(s):  
J. Frank ◽  
B. F. McEwen ◽  
M. Radermacher ◽  
C. L. Rieder
Keyword(s):  
Tilt Angle ◽  
Tomographic Reconstruction ◽  
3D Structure ◽  
Three Dimensional ◽  
Thick Section ◽  
Three Dimensional Reconstruction ◽  
Axis Ratio ◽  
Dimensional Reconstruction ◽  
Cellular Components

The tomographic reconstruction from multiple projections of cellular components, within a thick section, offers a way of visualizing and quantifying their three-dimensional (3D) structure. However, asymmetric objects require as many views from the widest tilt range as possible; otherwise the reconstruction may be uninterpretable. Even if not for geometric obstructions, the increasing pathway of electrons, as the tilt angle is increased, poses the ultimate upper limitation to the projection range. With the maximum tilt angle being fixed, the only way to improve the faithfulness of the reconstruction is by changing the mode of the tilting from single-axis to conical; a point within the object projected with a tilt angle of 60° and a full 360° azimuthal range is then reconstructed as a slightly elliptic (axis ratio 1.2 : 1) sphere.

SIMULATION AND EARLY WARNING OF NATURAL AND TECHNOGENIC INFLUENCES IN COASTAL AREAS IN THE SEA OF AZOV

2017 ◽  
Author(s):  
Tatiana Shulga ◽  
Tatiana Shulga ◽  
Leonid Cherkesov ◽  
Leonid Cherkesov
Keyword(s):  
Model Comparison ◽  
Three Dimensional ◽  
Storm Surges ◽  
Ecological Condition ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
Waves And Currents ◽  
Coordinate Model ◽  
Passive Admixture ◽  
Comparison Of The Results

In this work, the waves and currents generated by prognostic wind in the Sea of Azov are investigated using a three-dimensional nonlinear sigma-coordinate model. The mathematical model was also used for studying the transformation of passive admixture in the Sea of Azov, caused by the spatiotemporal variations in the fields of wind and atmospheric pressure, obtained from the prediction SKIRON model. Comparison of the results of numerical calculations and the data of field observations, obtained during the action of the wind on a number of hydrological stations was carried out. The evolutions of storm surges, velocities of currents and the characteristics of the pollution region at different levels of intensity of prognostic wind and stationary currents were found. The results of a comprehensive study allow reliably estimate modern ecological condition of offshore zones, develop predictive models of catastrophic water events and make science-based solutions to minimize the possible damage.

Handheld Laser Scanner Research

2019 ◽  
Vol 952 (10) ◽  
pp. 47-54
Author(s):  
A.V. Komissarov ◽  
A.V. Remizov ◽  
M.M. Shlyakhova ◽  
K.K. Yambaev
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Test Site ◽  
Optical Systems ◽  
Advantages And Disadvantages ◽  
Site Survey ◽  
Laser Scanners ◽  
Three Dimensional Models ◽  
The Stability

The authors consider hand-held laser scanners, as a new photogrammetric tool for obtaining three-dimensional models of objects. The principle of their work and the newest optical systems based on various sensors measuring the depth of space are described in detail. The method of simultaneous navigation and mapping (SLAM) used for combining single scans into point cloud is outlined. The formulated tasks and methods for performing studies of the DotProduct (USA) hand-held laser scanner DPI?8X based on a test site survey are presented. The accuracy requirements for determining the coordinates of polygon points are given. The essence of the performed experimental research of the DPI?8X scanner is described, including scanning of a test object at various scanner distances, shooting a test polygon from various scanner positions and building point cloud, repeatedly shooting the same area of the polygon to check the stability of the scanner. The data on the assessment of accuracy and analysis of research results are given. Fields of applying hand-held laser scanners, their advantages and disadvantages are identified.

Modeling of aortic valve stenosis using fluid-structure interaction method

Perfusion ◽  
2021 ◽  
pp. 026765912199854
Author(s):  
Mohammad Javad Ghasemi Pour ◽  
Kamran Hassani ◽  
Morteza Khayat ◽  
Shahram Etemadi Haghighi
Keyword(s):  
Blood Flow ◽  
Aortic Valve ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Relaxation Phase ◽  
Exercise Condition ◽  
Time Dependent Domain ◽  
Comparison Of The Results

Background and objectives: Fluid structure interaction (FSI) is defined as interaction of the structures with contacting fluids. The aortic valve experiences the interaction with blood flow in systolic phase. In this study, we have tried to predict the hemodynamics of blood flow through a normal and stenotic aortic valve in two relaxation and exercise conditions using a three-dimensional FSI method. Methods: The aorta valve was modeled as a three-dimensional geometry including a normal model and two others with 25% and 50% stenosis. The geometry of the aortic valve was extracted from CT images and the models were generated by MMIMCS software and then they were implemented in ANSYS software. The pulsatile flow rate was used for all cases and the numerical simulations were conducted based on a time-dependent domain. Results: The obtained results including the velocity, pressure, and shear stress contours in different systolic time sequences were explained and discussed. The maximum blood flow velocity in relaxation phase was obtained 1.62 m/s (normal valve), 3.78 m/s (25% stenosed valve), and 4.73 m/s (50% stenosed valve). In exercise condition, the maximum velocities are 2.86, 4.32, and 5.42 m/s respectively. The maximum blood pressure in relaxation phase was calculated 111.45 mmHg (normal), 148.66 mmHg (25% stenosed), and 164.21 mmHg (50% stenosed). However, the calculated values in exercise situation were 129.57, 163.58, and 191.26 mmHg. The validation of the predicted results was also conducted using existing literature. Conclusions: We believe that such model are useful tools for biomechanical experts. The further studies should be done using experimental data and the data are implemented on the boundary conditions for better comparison of the results.

GEOPOLIS software tools – Groundwater flow modeling at deep repository of liquid radioactive waste at Severny test site

2021 ◽  
pp. 91-97
Author(s):  
V. V. Suskin ◽  
A. V. Rastorguev ◽  
I. V. Kapyrin
Keyword(s):  
Groundwater Flow ◽  
Flow Model ◽  
Liquid Radioactive Waste ◽  
Three Dimensional ◽  
Test Site ◽  
Geological Structure ◽  
Groundwater Flow Model ◽  
Flow Modeling ◽  
Three Dimensional Model ◽  
Groundwater Flow Modeling

This article discusses a three-dimensional groundwater flow model of a deep disposal facility at Severny test site. The three-dimensional model is a part of the certified software GEOPOLIS, based on the hydrogeological code GeRa (Geomigration of Radionuclides) serving as the calculation engine. This study describes the hydrogeological patterning of the groundwater flow model, as well as the results of calibration and verification of the model water heads with respect to the data of monitoring for more than 40 years of the deep repository exploitation. The article begins with a brief overview of the previously developed hydrogeological models of this object and continues with a description of the geological structure of the territory, and with a substantiation of the boundaries and parameters of the model. The results of groundwater flow modeling, model calibration, verification and estimation of discrepancy between the model results and monitoring data are shown. The comparison of the modeled and observed water heads in the stationary conditions (before the start of injection) and during operation of the deep repository allows making conclusion on the quality of calibration.

Sign in / Sign up

Export Citation Format

Share Document