scholarly journals Separation of Long-Crested Nonlinear Bichromatic Waves into Incident and Reflected Components

2019 ◽  
Vol 7 (2) ◽  
pp. 39 ◽  
Author(s):  
Thomas Lykke Andersen ◽  
Mads R. Eldrup ◽  
Maria Clavero
Keyword(s):  
Physical Model ◽  
Nonlinear Waves ◽  
New Method ◽  
Regular Waves ◽  
Third Order ◽  
Reflected Waves ◽  
The Third ◽  
New Methods ◽  
Linear Waves ◽  
Physical Model Tests

Methods for the separation of long-crested linear waves into incident and reflected waves have existed for more than 40 years. The present paper presents a new method for the separation of nonlinear bichromatic long-crested waves into incident and reflected components, as well as into free and bound components. The new method is an extension of a recently proposed method for the separation of nonlinear regular waves. The new methods include both bound and free higher harmonics, which is important for nonlinear waves. The applied separation method covers interactions to the third order, but can easily be extended to a higher orders. Synthetic tests, as well as physical model tests, showed that the method accurately predict the bound amplitudes and incident and reflected surface elevations of nonlinear bichromatic waves. The new method is important in order to be able to describe the detailed characteristics of nonlinear bichromatic waves and their reflection.

Reduction of Wave Pressures on Vertical Seawall/Caissons Due to an Offshore Breakwater

2003 ◽  
Author(s):  
Muthukuru G. MuniReddy ◽  
Subramanian Neelamani
Keyword(s):  
Physical Model ◽  
Material Selection ◽  
Extreme Wave ◽  
Regular Waves ◽  
Wave Flume ◽  
Seaward Side ◽  
Fluid Mass ◽  
Physical Model Tests ◽  
Static Nature ◽  
Selection Of

Estimation of wave pressures on vertical impermeable caissons and seawall is needed to determine the dimensions and appropriate material selection of the structure. Reduction of extreme wave loadings (pressures) by constructing an offshore breakwater on seaward side of these structures is investigated. A series of physical model tests were carried out in a wave flume to examine the performance of the defense structure (offshore breakwater) in reducing the wave pressures on the seawall/caisson. Quasi-static nature of the wave pressures was observed due to piling-up of fluid mass behind the breakwater. The influence of the pool length on reduction of pressures on seawall/caisson is also investigated for regular waves.

TRAVELTIME CURVES FOR REFLECTIONS IN DIPPING LAYERS

Geophysics ◽  
1976 ◽  
Vol 41 (3) ◽  
pp. 425-440 ◽  
Author(s):  
Anthony F. Gangi ◽  
Sung Jin Yang
Keyword(s):  
Second Order ◽  
Computationally Efficient ◽  
Third Order ◽  
Reflected Waves ◽  
First Order ◽  
The Third ◽  
Order Curve ◽  
Standard Deviations ◽  
Tracing Techniques ◽  
Source Array

The traveltimes for reflected waves from plane, dipping layer interfaces for split‐spread arrays and CGP gathers are determined by a computationally efficient method. The computational efficiency is obtained by (1) interpolating the traveltimes for particular source‐receiver distances from least‐squares curves fitted to traveltime data rather than by using iterative ray‐tracing techniques, and (2) using the traveltime curves for a fixed source to determine those for other source locations and for CGP gathers over the same dipping layer interfaces. The additional computations necessary in this latter case are minimal when this approach is used. The traveltime curves for other source locations and CGP gathers are obtained by taking advantage of the fact that the traveltimes and travel distances for parallel rays are simply related for plane, dipping layer interfaces. For the fixed source array, standard deviations between 0.95 msec for the fourth interface (in a four layer model) and 9.5 msec for the first interface were obtained when the traveltimes t(x) were fitted to a second order curve: [Formula: see text]. These standard deviations decreased to 0.81 and 3.5 msec, respectively, when a third order curve [Formula: see text] was used. The standard deviations became 2.97 and 0 msec, respectively, for a second order curve in [Formula: see text]; and 0.95 and 0 msec, respectively, for the third order curve: [Formula: see text]. For a CGP gather over the same layers, the standard deviations were 0.84 and 0 msec for the fourth and first interfaces, respectively, when the traveltime data were fitted to a first order curve in [Formula: see text]. These standard deviations became 0.10 and 0 msec, respectively, when the curve fitted was: [Formula: see text]. Errors in the traveltimes for a fitted curve, [Formula: see text], in a CGP gather for the third interface at a depth of about 5000 ft were less than 0.5 msec for source‐receiver separations up to 5000 ft. For the same interface, errors were much less than 0.1 msec over the same separations for the fitted curve: [Formula: see text].

scholarly journals WAVE REFLECTION FROM BERM BREAKWATERS

2020 ◽  
pp. 7
Author(s):  
Karthika Krishna Pillai ◽  
Amir Etemad-Shahidi ◽  
Charles Lemckert
Keyword(s):  
Physical Model ◽  
Wave Reflection ◽  
Model Tests ◽  
Reflection Coefficients ◽  
Data Sets ◽  
Empirical Formulas ◽  
Reflected Waves ◽  
Physical Model Tests ◽  
The Stability

Wave reflection from berm breakwaters is an area less focused as these structures are generally considered to have relatively low reflection levels. However, the reflected waves may compromise the stability of the structure by inducing scour at the toe and may enhance harbour access risk (Zanuttigh et al., 2013). Hence, it is necessary that the reflection coefficients are predicted accurately. Several empirical formulas such as Postma (1989), Alikhani (2000), Zanuttigh and Van der Meer (2008) and Van der Meer and Sigurdarson (2016) have been suggested for the prediction of wave reflection, Kr. In this study, physical model tests were conducted to supplement the existing berm breakwater data sets in the CLASH database (Zanuttigh et al., 2016). The measured reflection coefficients were then compared with those of the existing formulas to evaluate their performance.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/WXIoa_ae-1Y

The pKBH+ calculation of strong bases: A revision of various methods

1987 ◽  
Vol 52 (2) ◽  
pp. 299-307 ◽  
Author(s):  
Begoña García ◽  
José M. Leal
Keyword(s):  
Perchloric Acid ◽  
Infinite Dilution ◽  
Polynomial Function ◽  
Acid Base ◽  
Third Order ◽  
Acid Media ◽  
The Third ◽  
Aniline Derivatives ◽  
New Methods

The pKBH+ values have been obtained for seventeen acid-base equilibriums corresponding to thirteen aniline derivatives in dilute perchloric acid media in the pH region at 25 °C using the spectrophotometric technique. By revising the method of extrapolation to infinite dilution it was possible to introduce new methods for calculating pKBH+ values of strong bases by means of the functions logI = f(pH) and pKap = f(pH). The equation - logfBH+/fB = f(pH) - has been proved to conform to a polynomial function of the third order and is applicable to each compound.

scholarly journals Applying Quran Security and Hamming CodesFor Preventing of Text Modification

2011 ◽  
Vol 8 (2) ◽  
pp. 408-418
Author(s):  
Baghdad Science Journal
Keyword(s):  
Prime Number ◽  
Error Detection ◽  
New Method ◽  
Detection Methods ◽  
Second Step ◽  
Huge Number ◽  
The Third ◽  
New Methods ◽  
The World ◽  
Encryption Method

The widespread of internet allover the world, in addition to the increasing of the huge number of users that they exchanged important information over it highlights the need for a new methods to protect these important information from intruders' corruption or modification. This paper suggests a new method that ensures that the texts of a given document cannot be modified by the intruders. This method mainly consists of mixture of three steps. The first step which barrows some concepts of "Quran" security system to detect some type of change(s) occur in a given text. Where a key of each paragraph in the text is extracted from a group of letters in that paragraph which occur as multiply of a given prime number. This step cannot detect the changes in the reordering letters or words of the paragraph and text without changing the letters themselves. So, the next step uses one of the error detection methods which is named Hamming Codes to find out the locations of the change in the received text. After that; at the third step, RSA as a primary encryption method has been used to encrypt the keys extracted to the first step and second step in order to prevent the intruders to break down the security of the method.

scholarly journals Modifikasi Metode Householder Tiga Parameter yang Bebas Turunan Kedua dengan Orde Konvergensi Optimal

2021 ◽  
Vol 18 (1) ◽  
pp. 62-74
Author(s):  
Wartono ◽  
M Zulianti ◽  
Rahmawati
Keyword(s):  
Numerical Simulation ◽  
Iterative Method ◽  
Iterative Methods ◽  
Efficiency Index ◽  
New Method ◽  
Third Order ◽  
The Third ◽  
New Iterative Method ◽  
Better Than ◽  
Taylor’S Series

The Householder’s method is one of the iterative methods with a third-order convergence that used to solve a nonlinear equation. In this paper, the authors modified the iterative method using the expansion of second order Taylor’s series and approximated its second derivative using equality of two the third-order iterative methods. Based on the results of the study, it was found that the new iterative method has a fourth-order of convergence and requires three evaluations of function with an efficiency index of 1,587401. Numerical simulation is given by using several functions to compare the performance between the new method with other iterative methods. The results of numerical simulation show that the performance of the new method is better than other iterative methods.

scholarly journals New methods for space debris collision assessment

2014 ◽  
Vol 9 (S310) ◽  
pp. 150-153
Author(s):  
Daniel Casanova ◽  
Chiara Tardioli ◽  
Anne Lemaître
Keyword(s):  
Space Debris ◽  
New Method ◽  
Real Problem ◽  
Short List ◽  
Efficient Tool ◽  
The Third ◽  
New Methods ◽  
Real Risk ◽  
New Space ◽  
The Creation

AbstractCollisions between two pieces of space debris or between a piece of debris and an operative satellite is a real problem. Furthermore, collisions are responsible for the creation of new space debris systematically. The way to exclude the possibility of a collision consists of analysing the trajectories and looking for a time of coincidence. However, the analysis of all pairs of objects collected in a large orbit catalogue is unfeasible. The proposed method consists of reducing the possible pairs of candidates for a collision into a short list of pairs at real risk of collision. The method is based on a three-filter sequence: the first two filters are based on the geometry of the orbits, while the third one searches for a time of coincidence. This new method is tested resulting into an efficient tool for space debris collision assessment.

Research of Fault Feature Extraction Based on High Order Cyclic Statistics for Reciprocating Compressor Gas Valves

2010 ◽  
Vol 44-47 ◽  
pp. 2094-2098
Author(s):  
Shu Lin Liu ◽  
You Fu Tang ◽  
Ji Cheng Liu ◽  
Ying Hui Liu
Keyword(s):  
Feature Extraction ◽  
New Method ◽  
Reciprocating Compressor ◽  
Third Order ◽  
Vibration Signals ◽  
The Third ◽  
Signal Features ◽  
Fault Features ◽  
Cyclic Statistics ◽  
Fault Feature Extraction

. This paper proposes an approach of fault feature extraction for reciprocating compressor gas valves based on theory of cyclic statistics. First, the strength and weakness of the third-order cyclic statistics in extracting signal features are investigated by simulation signals. Since vibration signals for reciprocating compressor gas valves are of typical cyclic stationary, a new method of fault feature extraction is then proposed based on the simulation results. The method utilizes the cyclic bi-spectrum to extract fault features for the corresponding frequencies. The results show that the cyclic bi-spectrum characteristics for typical faults of gas valves are apparently different, and that the typical faults of reciprocating compressor gas valves can be diagnosed exactly. So the new method proposed in this paper is effective and feasible.

Probe size and 5th-order aberration

1987 ◽  
Vol 45 ◽  
pp. 134-135 ◽  
Author(s):  
Zhifeng Shao
Keyword(s):  
Electron Probe ◽  
Spherical Aberration ◽  
Wave Length ◽  
Cylindrical Symmetry ◽  
Electron Wave ◽  
Third Order ◽  
The Third ◽  
Probe Radius ◽  
Small Probe ◽  
Probe Size

A small electron probe has many applications in many fields and in the case of the STEM, the probe size essentially determines the ultimate resolution. However, there are many difficulties in obtaining a very small probe.Spherical aberration is one of them and all existing probe forming systems have non-zero spherical aberration. The ultimate probe radius is given byδ = 0.43Csl/4ƛ3/4where ƛ is the electron wave length and it is apparent that δ decreases only slowly with decreasing Cs. Scherzer pointed out that the third order aberration coefficient always has the same sign regardless of the field distribution, provided only that the fields have cylindrical symmetry, are independent of time and no space charge is present. To overcome this problem, he proposed a corrector consisting of octupoles and quadrupoles.

Sign in / Sign up

Export Citation Format

Share Document