scholarly journals Particle System-Based Multi-Hierarchy Dynamic Visualization of Ocean Current Data

2021 ◽  
Vol 10 (10) ◽  
pp. 667
Author(s):  
Qingtong Shi ◽  
Bo Ai ◽  
Yubo Wen ◽  
Wenjun Feng ◽  
Chenxi Yang ◽  
...  
Keyword(s):  
Particle System ◽  
Three Dimensional ◽  
Current Data ◽  
Ocean Current ◽  
Viewing Distance ◽  
Dynamic Visualization ◽  
Earth Environment ◽  
Adaptive Adjustment ◽  
Series Of Experiments ◽  
Seed Points

In three-dimensional (3D) digital Earth environment, there are many problems when using the existing methods to express the ocean current, such as uneven distribution of seed points, density leap in scale change and messy visualization. In this paper, a new dynamic visualization method of multi-hierarchy flow field based on particle system is proposed; Specifically, three typical spherical uniform algorithms are studied and compared, and the streamline becoming denser from the equator to the poles on globe is eliminated by placing seed points using Marsaglia polar method as the most efficient. In addition, a viewport-adaptive adjustment algorithm is proposed, which realizes that the density of particles is always suitable to any viewing distance during continuous zooming. To solve the visual representation deficiency, we design a new dynamic pattern to enhance the expression and perception of current, which makes up for the shortcoming of the arrow glyph and streamline methods. Finally, a prototype of GPU parallel and viewport coherence is achieved, whose feasibility and effectiveness are verified by a series of experiments. The results show that our method can not only represent ocean current data clearly and efficiently, but also has outstanding uniformity and hierarchy effect.

Cyclopean Vision, Size Estimation, and Presence in Orthostereoscopic Images

2001 ◽  
Vol 10 (3) ◽  
pp. 312-330 ◽  
Author(s):  
Bernard Harper ◽  
Richard Latto
Keyword(s):  
Visual System ◽  
Three Dimensional ◽  
Point Of View ◽  
Psychophysical Experiment ◽  
Size Estimation ◽  
Human Form ◽  
Image Capture ◽  
Series Of Experiments ◽  
Abstract Shapes ◽  
And Control

Stereo scene capture and generation is an important facet of presence research in that stereoscopic images have been linked to naturalness as a component of reported presence. Three-dimensional images can be captured and presented in many ways, but it is rare that the most simple and “natural” method is used: full orthostereoscopic image capture and projection. This technique mimics as closely as possible the geometry of the human visual system and uses convergent axis stereography with the cameras separated by the human interocular distance. It simulates human viewing angles, magnification, and convergences so that the point of zero disparity in the captured scene is reproduced without disparity in the display. In a series of experiments, we have used this technique to investigate body image distortion in photographic images. Three psychophysical experiments compared size, weight, or shape estimations (perceived waist-hip ratio) in 2-D and 3-D images for the human form and real or virtual abstract shapes. In all cases, there was a relative slimming effect of binocular disparity. A well-known photographic distortion is the perspective flattening effect of telephoto lenses. A fourth psychophysical experiment using photographic portraits taken at different distances found a fattening effect with telephoto lenses and a slimming effect with wide-angle lenses. We conclude that, where possible, photographic inputs to the visual system should allow it to generate the cyclopean point of view by which we normally see the world. This is best achieved by viewing images made with full orthostereoscopic capture and display geometry. The technique can result in more-accurate estimations of object shape or size and control of ocular suppression. These are assets that have particular utility in the generation of realistic virtual environments.

Three-dimensional auto-stereoscopic animated image with a long viewing distance using high-precision image correction

2009 ◽  
Author(s):  
Takehito Teraguchi ◽  
Hiromasa Yamashita ◽  
Ken Masamune ◽  
Takeyoshi Dohi ◽  
Hongen Liao
Keyword(s):  
High Precision ◽  
Three Dimensional ◽  
Viewing Distance ◽  
Image Correction

FUNDAMENTAL ANALYSIS OF THREE-DIMENSIONAL ‘NEAR FLING’

1993 ◽  
Vol 183 (1) ◽  
pp. 217-248 ◽  
Author(s):  
S. Sunada ◽  
K. Kawachi ◽  
I. Watanabe ◽  
A. Azuma
Keyword(s):  
Numerical Calculation ◽  
Hydrodynamic Force ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Added Mass ◽  
Opening Angle ◽  
Rotation Axes ◽  
Adequate Accuracy ◽  
Series Of Experiments ◽  
The Moment

A series of experiments on three-dimensional ‘near fling’ was carried out. Two pairs of plates, rectangular and triangular, were selected, and the distance between the rotation axes of the two plates of each pair was varied. The motion of the plates as well as the forces and the moment were measured, and the interference between the two plates of a pair was studied. In addition, a method of numerical calculation was developed to aid in the understanding of the experimental results. The interference between the two plates of a pair, which acted to increase both the added mass of each plate and the hydrodynamic force due to dynamic pressure, was noted only when the opening angle between the plates was small. The hydrodynamic forces were strongly influenced by separated vortices that occurred during the rotation. A method of numerical calculation, which took into account the effect both of interference between the plates and of separated vortices, was developed to give adequate accuracy in analyzing beating wings in ‘near fling’.

Analysis of a Balanced Breech System for the M1A1 Main Gun System Using Finite Element Techniques

1994 ◽  
Author(s):  
David A. Hopkins ◽  
Stephen A. Wilkerson
Keyword(s):  
Finite Element ◽  
Kinetic Energy ◽  
Three Dimensional ◽  
System Change ◽  
Sine Wave ◽  
Fe Model ◽  
Firing Cycle ◽  
Entire System ◽  
Tube Shape ◽  
Series Of Experiments

Abstract A series of experiments were recently conducted in an attempt to reduce the dynamic motions of the M256 gun system during firing. Data collected during these experiments included the motion of the gun tube and breech mechanism for both the standard (unbalanced) configuration and a modified system in which mass was added such that the breech center of gravity (CG) was coincident with the gun tube centerline. The results indicated a noticeable change in the dynamic motions between these two configurations. Prior experiments indicated that the unbalanced breech drops several tenths of a millimeter during the firing cycle. Also, the gun tube whipping motion, which is induced by the powder pressure couple, vibrates the gun in a similar fashion regardless of ammunition type. Furthermore, the gun tube shape at shot exit always resembles a distorted sine wave. This behavior was noted for both heat and kinetic energy (KE) munitions in previous unbalanced breech tests conducted with the M256 gun. However, when the breech is balanced, the dynamics of the entire system change in both shape and magnitude of displacement. This report attempts to explain the results of the tests performed. This was accomplished using a three-dimensional (3-D), transient, finite element (FE) model of the entire system, which included breech, gun tube, trunnion mount, recoil, and projectile. Results from these calculations provide an explanation of the observed behavior of the system. Insight acquired about the nature of the system’s behavior was then used to propose several simple improvements to the M256 gun system which can be applied to gun systems in general. Implementation of these changes should decrease the shot-to-shot variability associated with gun accuracy.

Addition of Artificial Loads to Long-Eared Bats Plecotus Auritus: Handicapping Flight Performance

1991 ◽  
Vol 161 (1) ◽  
pp. 285-298 ◽  
Author(s):  
PATSY M. HUGHES ◽  
JEREMY M. V. RAYNER
Keyword(s):  
Total Mass ◽  
Three Dimensional ◽  
Flight Speed ◽  
Wing Loading ◽  
Wingbeat Frequency ◽  
Cost Of Transport ◽  
In Captivity ◽  
Series Of Experiments ◽  
Predicted Values ◽  
Optimal Approach

A series of experiments is described in which two brown long-eared bats Plecotus auritus Linnaeus (Chiroptera: Vespertilionidae) were flown in a 1mx1mx4.5m flight enclosure at a range of body masses (n=9 experiments for a female bat, and n = 11 for a male bat). The highest three of these masses incorporated artificial loads. Stroboscopic stereophotogrammetry was used to make three-dimensional reconstructions (n=124) of the bats' flight paths. Over the entire range of experiments, wing loading was increased by 44% for the female and 46% for the male bat. Effects arising from captivity were controlled for: experiments at certain wing loadings were repeated after a period in captivity and the response to load was found to be unaltered. Flight speed fell with total mass M or with wing loading, varying as M−0.49 in the female and M−0.42 in the male bat. Wingbeat frequency increased with total mass or wing loading, varying as M0.61 in the female and M0.44in the male bat. Hence frequency, but not speed, changed with mass in the direction predicted by aerodynamic theory. These results were used in a mathematical model to predict wingbeat amplitude, flight power and cost of transport. The model was also used to estimate the optimal flight speeds Vmr and Vmp. The model predicted that amplitude increases with load. Measurements of wingbeat amplitude did not differ significantly from the predicted values. The observed flight speed was below the predicted minimum power speed Vmp (which increases with load), and diverged further from this with progressive loading. The increase in cost of flight calculated by the model over the range of wing loadings was approximately double that which it would have been had the bats adopted the optimal approach predicted by the model. The limitations inherent in the theoretical model, and the possible constraints acting on the animals, are discussed.

Three-Dimensional Dynamic Visualization of Coastal Zones for Sea-land Integration

2020 ◽  
Vol 99 (sp1) ◽  
pp. 85
Author(s):  
Bo Ai ◽  
YunHang Xia ◽  
ZhiGang Li ◽  
FanLin Yang ◽  
Min Ji
Keyword(s):  
Three Dimensional ◽  
Dynamic Visualization ◽  
Coastal Zones

Sunspot and Group Number: Recent advances from historical data

2018 ◽  
Vol 14 (A30) ◽  
pp. 156-159 ◽  
Author(s):  
Frédéric Clette ◽  
José M. Vaquero ◽  
María Cruz Gallego ◽  
Laure Lefèvre
Keyword(s):  
Sunspot Number ◽  
Maunder Minimum ◽  
Current Data ◽  
Activity Level ◽  
Historical Evidence ◽  
The Earth ◽  
Earth Environment ◽  
Group Number ◽  
Dalton Minimum

AbstractDue to its unique 400-year duration, the sunspot number is a central reference for understanding the long-term evolution of solar activity and its influence on the Earth environment and climate. Here, we outline current data recovery work. For the sunspot number, we find historical evidence of a disruption in the source observers occurring in 1947–48. For the sunpot group number, recent data confirm the clear southern predominance of sunspots during the Maunder Minimum, while the umbra-penumbra ratio is similar to other epochs. For the Dalton minimum, newly recovered historical observations confirm a higher activity level than in a true Grand Minimum.

Three-Dimensional Structures in Experimental Density Currents

2007 ◽  
Author(s):  
B. Firoozabadi ◽  
H. Afshin ◽  
E. Safaaee
Keyword(s):  
Salt Solution ◽  
Chemical Elements ◽  
Three Dimensional ◽  
Lateral Spreading ◽  
Current Data ◽  
Density Current ◽  
Density Currents ◽  
Ambient Water ◽  
Data Set ◽  
Bed Slope

Density currents are continuous currents which move down-slope due to the fact that their density is greater than that of ambient water. The density difference is caused by temperature differences, chemical elements, dissolved materials, or suspended sediment. Many researchers have studied the density current structures, their complexities and uncertainties. However, there is not a detailed 3-D turbulent density current data set perfectly. In this work, the structure of 3-dimensional salt solution density currents is investigated. A laboratory channel was used to study the flow resulting from the release of salt solution into freshwater over an inclined bed. The experiments were conducted with different bottom slopes, inlet concentrations and flow rates. In these tests, the instantaneous velocities are measured by an ADV apparatus (Acoustic Doppler Velocimeter). Results show that by increasing the bed-slope and inlet concentrations, the height of the current decreases. As the density current moves downward the channel or by increasing the discharge, the height of the density current increases. Finally, the effects of different variables such as the bed slope, concentration and flow rate of entering fluid on the velocity profile in different distances from the entrance is studied. The entrainment coefficient, lateral spreading and drag coefficient of the bed and shear layer between salt solution and ambient water is discussed.

scholarly journals A Comparative Study on the Performance of a Horizontal Axis Ocean Current Turbine Considering Deflector and Operating Depths

2020 ◽  
Vol 12 (8) ◽  
pp. 3333
Author(s):  
Nauman Riyaz Maldar ◽  
Cheng Yee Ng ◽  
Lee Woen Ean ◽  
Elif Oguz ◽  
Ahmad Fitriadhy ◽  
...  
Keyword(s):  
Fluid Pressure ◽  
Three Dimensional ◽  
Horizontal Axis ◽  
Ocean Current ◽  
Power Coefficient ◽  
Cfd Simulations ◽  
Torque Coefficient ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Design ◽  
Current Turbine

Several different designs and prototypes of ocean current turbines have been tested over recent years. For every design test, emphasis is given to achieving an optimum power output from the flow. In this study, the performance of a Horizontal Axis Ocean Current Turbine (HAOCT) has been investigated using three-dimensional Computational Fluid Dynamics (CFD) simulations for three cases, namely, (1) a turbine without a deflector, (2) a turbine with a deflector, and (3) a turbine with a deflector operating at a higher fluid depth. The turbine design was modeled in DesignModeler software and simulations were carried out in commercial CFD software Flow-3D. The Torque Coefficient (Cm) and Power Coefficient (Cp) for the turbine have been investigated for a certain range of Tip-Speed Ratios (TSRs) in a flow velocity of 0.7 m/s. Furthermore, comparisons have been made to demonstrate the effect of the deflector on the performance of the turbine and the influence of a higher fluid pressure on the same. The results from the simulations indicate that the higher value of Cp was achieved for Case 2 as compared to the other two cases. The findings from the study indicate that the use of the deflector enhances the performance of the turbine. Furthermore, a higher fluid pressure acting on the turbine has a significant effect on its performance.

scholarly journals Study on the Effect of the Three-Dimensional Electrode in Degradation of Methylene Blue by Lithium Modified Rectorite

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Jian Huang ◽  
Yin’an Ming ◽  
Ying Du ◽  
Yingru Wang ◽  
Ci’en Wang
Keyword(s):  
Methylene Blue ◽  
Electrical Property ◽  
Adsorption Property ◽  
Low Cost ◽  
Three Dimensional ◽  
Cell Voltage ◽  
Operating Conditions ◽  
The Novel ◽  
Synthetic Solution ◽  
Series Of Experiments

This study presents the electrochemical degradation of methylene blue (MB) wastewater in a synthetic solution using three-dimensional particle electrodes. The novel particle electrodes were fabricated in this work using the lithium modified rectorite (Li-REC). The adsorption property of the fabricated particle electrodes was studied in a series of experiments. The optimum electrochemical operating conditions of plate distance, cell voltage, and concentration of electrolyte were 2 cm, 9 V, and 0.06 mol L−1, respectively. It was also found that microwave irradiation can effectively improve the adsorption property and electrical property of the fabricated electrodes. In addition, the scanning electron microscope (SEM) of the fabricated electrodes was investigated. The experimental results revealed the order of adsorption property and electrical property of the fabricated electrodes. So, fabricated electrodes are not only of low cost and mass produced, but also efficient to achieve decolorization of MB solution.

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