scholarly journals BEACH PROFILE CHARACTERISTICS DUE TO THE INCLINED WAVES

1988 ◽  
Vol 1 (21) ◽  
pp. 121
Author(s):  
Tai-Wen Hsu ◽  
Shan-Hwei Ou
Keyword(s):  
Three Dimensional ◽  
Relative Importance ◽  
Wave Steepness ◽  
Beach Profile ◽  
Empirical Relationships ◽  
Profile Changes ◽  
Series Of Experiments ◽  
Wave Angle ◽  
Profile Characteristics ◽  
Movable Bed

The result of a theoretical approach shows that the beach profile characteristics is governed by a modified Iribarren number which includes the effects among the factors of initial beach slope, wave angle and wave steepness. A series of experiments are conducted in a three-dimensional movable bed model on the conditions of two different initial beach slopes, two incident wave angles as well as several erosive wave steepnesses. The relative importance of each factor involved in the parameter is discussed. It is shown that the modified Iribarren number is effective in the analysis, of beach profile characteristics under the action of inclined waves. The empirical relationships between beach profile changes and the modified Iribarren number are proposed on the basis of experimental results.

scholarly journals UNDERWATER MOUND FOR THE PROTECTION OF DURBAN'S BEACHES

1970 ◽  
Vol 1 (12) ◽  
pp. 62 ◽  
Author(s):  
J.A. Zwaborn ◽  
G.A.W. Fromme ◽  
J.B. FitzPatrick
Keyword(s):  
Settling Velocity ◽  
Scale Effects ◽  
Similarity Criterion ◽  
Test Results ◽  
Beach Profile ◽  
Reasonable Degree ◽  
Model Predictions ◽  
Profile Changes ◽  
High Degree ◽  
Movable Bed

The construction of an underwater mound of sand for the protection and improvement of Durban's beaches has been recommended on the basis of intensive investigations These investigations included prototype measurements of beach changes as related to recorded sea conditions, basic scaling tests in which these beach changes were reproduced to scale in movable bed models and tests of the proposed underwater mound in models, using different scales in order to eliminate possible scale effects The test results showed that, provided the shear-settling velocity similarity criterion is satisfied, beach changes can be reproduced in a movable bed model to a reasonable degree of accuracy Optimum dimensions for the cross section of the mound were determined on the basis of the criterion for erosive and non-erosive wave conditions which was derived from the prototype beach profile changes and confirmed by model tests The resulting dimensions are a mound of sand about 4 5 km long, about 1 200 m offshore, reaching to 7 3 m below LWOST, with side slopes of 1 in 25 and a crest width of 61 m 3 3 Of the total quantity required (8 000 000 m ) some 2 500 000 m of sand, available from harbour dredging works in Durban Bay, had been dumped by May, 1970 Model predictions on mound stability and beach improvements were confirmed to a high degree of accuracy by the full scale events.

scholarly journals TWO-DIMENSIONAL EMPIRICAL EIGENFUNCTION MODEL FOR THE ANALYSIS AND PREDICTION OF BEACH PROFILE CHANGES

1986 ◽  
Vol 1 (20) ◽  
pp. 87 ◽  
Author(s):  
T.W. Hsu ◽  
S.R. Liaw ◽  
S.K. Wang ◽  
S.H. Ou
Keyword(s):  
Breaking Waves ◽  
Relative Importance ◽  
Two Dimensional ◽  
Coastal Structures ◽  
Beach Profile ◽  
Radiation Stress ◽  
Profile Data ◽  
Profile Changes ◽  
D Model ◽  
Profile Change

A two-dimensional empirical eigenfunction model is proposed for the analysis and the prediction of beach profile change due to longshore and cross-shore sediment transports. Beach profile data from Redhill coast, Taiwan, measured every two months at 150 meters interval along the detached breakwaters are analyzed and the relative importance from two directions is investigated. Furthermore, by employing the method of Markov process and linear regression, a prediction model is formulated which takes into account the effect of breaking waves, bottom sediment and radiation stress of waves. This 2-D model is shown to be effective in the analysis and the prediction of beach changes near the coastal structures.

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.

scholarly journals Improvement on Permeability of Cyclic Peptide/Peptidomimetic: Backbone N-Methylation as A Useful Tool

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 311
Author(s):  
Yang Li ◽  
Wang Li ◽  
Zhengshuang Xu
Keyword(s):  
Cyclic Peptides ◽  
Cyclic Peptide ◽  
Three Dimensional ◽  
Conformational Space ◽  
Cell Permeability ◽  
Relative Importance ◽  
Intrinsic Properties ◽  
Surface Areas ◽  
Synthetic Methodologies ◽  
Three Dimensional Configuration

Peptides have a three-dimensional configuration that can adopt particular conformations for binding to proteins, which are well suited to interact with larger contact surface areas on target proteins. However, low cell permeability is a major challenge in the development of peptide-related drugs. In recent years, backbone N-methylation has been a useful tool for manipulating the permeability of cyclic peptides/peptidomimetics. Backbone N-methylation permits the adjustment of molecule’s conformational space. Several pathways are involved in the drug absorption pathway; the relative importance of each N-methylation to total permeation is likely to differ with intrinsic properties of cyclic peptide/peptidomimetic. Recent studies on the permeability of cyclic peptides/peptidomimetics using the backbone N-methylation strategy and synthetic methodologies will be presented in this review.

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’.

A Meso-Electro-Mechanical Model for PMN-PT-BT Ceramics Behavior

2001 ◽  
Author(s):  
Jinghong Fan
Keyword(s):  
Phase Transition ◽  
Mechanical Model ◽  
Three Dimensional ◽  
Constitutive Behavior ◽  
Rate Equations ◽  
State Variables ◽  
Empirical Relationships ◽  
Nonlinear Hysteresis ◽  
Fully Coupled ◽  
Maximum Permittivity

Abstract A three-dimensional, meso-electro-mechanical model has been formulated for description of PMN-PT-BT ceramics. Unlike the experimentally fit models and phenomenological models which are based on state variables and/or empirical relationships, this fully coupled, computational mesomechanics model for polycrystalline PMN-PT-BT ceramics is developed based on considerations of constitutive behavior of single crystals. Specifically, domain wall nucleation and evolution rate equations are proposed in this work to describe the nonlinear hysteresis behavior of these ceramics near the phase transition temperature with maximum permittivity.

Modeling beach profile changes by typhoon impacts at Xiamen coast

2018 ◽  
Vol 95 (3) ◽  
pp. 783-804
Author(s):  
Kai Yin ◽  
Sudong Xu ◽  
Wenrui Huang ◽  
Rui Li ◽  
Hong Xiao
Keyword(s):  
Beach Profile ◽  
Profile Changes

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.

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