Statistical Properties of Envelope Field for Gaussian Sea Surface

2002 ◽  
Author(s):  
Krzysztof Podgo´rski ◽  
Igor Rychlik
Keyword(s):  
Statistical Properties ◽  
Sea Surface ◽  
Two Dimensional ◽  
Wave Groups ◽  
One Dimensional ◽  
Sampling Distributions ◽  
Marine Application ◽  
Propagating Waves ◽  
Definition Of

The envelope process is a useful analytical tool which is often used to study wave groups. Most research on statistical properties of the envelope, and thus of wave groups, was focused on one dimensional records. However for the marine application, an appropriate concept should be two dimensional in space and variable in time. Although a generalization to higher dimensions was introduced by Adler (1978), little work was done to investigate its features. Since the envelope is not defined uniquely and its properties depend on a chosen version, we discuss the definition of the envelope field for a two dimensional random field evolving in time which serves as a model of irregular sea surface. Assuming Gaussian distribution of this field we derive sampling properties of the height of the envelope field as well as of its velocity. The latter is important as the velocity of the envelope is related to the rate at which energy is transported by propagating waves. We also study how statistical distributions of group waves differ from the corresponding ones for individual waves and how a choice of a version of the envelope affects its sampling distributions. Analyzing the latter problem helps in determination of the version which is appropriate in an application in hand.

Stress Measurements with a Two-Dimensional Real-Time System

1988 ◽  
Vol 32 ◽  
pp. 397-406 ◽  
Author(s):  
G.M. Borgonovi ◽  
C.P. Gazza
Keyword(s):  
Two Dimensional ◽  
Single Exposure ◽  
Time System ◽  
Real Time System ◽  
One Dimensional ◽  
Potential Source ◽  
Position Sensitive ◽  
Position Sensitive Detectors ◽  
Exposure Technique

Conventional methods of determination of residual stress in polycrystalline samples use either diffractometers or one-dimensional position-sensitive detectors. The most commonly used technique, the so-called "sin2ψ" method, requires several measurements at different angular positions of the sample. With diffractometers, two rotations are required, while with one-dimensional detectors, one rotation is required (except for the so-called single exposure technique, which requires two one-dimensional position-sensitive detectors). Rotation can be a potential source of errors if the sample is not aligned very carefully.

scholarly journals Determination of hard X-ray polarization from two-dimensional images

2020 ◽  
Vol 53 (6) ◽  
pp. 1559-1561
Author(s):  
Robert B. Von Dreele ◽  
Wenqian Xu
Keyword(s):  
Incident Beam ◽  
Beam Polarization ◽  
Two Dimensional ◽  
One Dimensional ◽  
X Ray ◽  
Dimensional Image ◽  
Two Dimensional Image ◽  
The Difference ◽  
Two Dimensional Images

An estimate of synchrotron hard X-ray incident beam polarization is obtained by partial two-dimensional image masking followed by integration. With the correct polarization applied to each pixel in the image, the resulting one-dimensional pattern shows no discontinuities arising from the application of the mask. Minimization of the difference between the sums of the masked and unmasked powder patterns allows estimation of the polarization to ±0.001.

scholarly journals Interferometric Techniques Applied to High Resolution Observation of the Solar Granulation

1979 ◽  
Vol 50 ◽  
pp. 30-1-30-6
Author(s):  
Claude Aime
Keyword(s):  
High Resolution ◽  
Power Spectrum ◽  
Statistical Properties ◽  
Two Dimensional ◽  
Solar Granulation ◽  
One Dimensional ◽  
Resolution Observation ◽  
Stellar Interferometry ◽  
High Resolution Observation

AbstractMichelson,one-dimensional, and two-dimensional apertures are used to obtain the statistical properties of the solar granulation. The calibration of the power spectrum is performed via Michelson stellar interferometry as well as by the use of changes in seeing conditions during speckle-interferometric measurements. The correction of 40 analyses, determined with Fried's parameter ro ranging between 2.5 cm and 11.5 cm, provides satisfactory convergence for frequencies up to 3 cycles per arc second

Determination of a convex body from the average of projections and stability results

1998 ◽  
Vol 123 (3) ◽  
pp. 561-569 ◽  
Author(s):  
K. K. SPRIESTERSBACH
Keyword(s):  
Convex Body ◽  
Two Dimensional ◽  
One Dimensional ◽  
Random Sections ◽  
Standard Projection ◽  
Stability Results ◽  
Projection Bodies

Analysis of projections of a convex body is a familiar topic in tomography. However, instead of considering standard projection bodies, this work investigates a convex body introduced by Schneider [8] which is a Minkowski average of projections. The question addressed here is similar to that posed by Goodey and Weil [4] with respect to Minkowski averages of sections, as opposed to projections, that is, can the shape of a convex body be determined from random sections? Their main result shows that a body K is determined by the average of its two-dimensional sections, but not by the average of its one-dimensional sections. The goal of this study is to uncover the extent to which a convex body is determined by the average of its projections.

scholarly journals Fluorescence Assay for the Determination of d-Panthenol Based on Novel Ring-Fused 2-Pyridone Derivative

2020 ◽  
Vol 21 (21) ◽  
pp. 8386
Author(s):  
Wiktor Kasprzyk ◽  
Tomasz Świergosz ◽  
Filip Koper
Keyword(s):  
Citric Acid ◽  
Nmr Spectra ◽  
Chemical Structure ◽  
Accurate Determination ◽  
Pharmaceutical Formulations ◽  
Two Dimensional ◽  
One Dimensional ◽  
Fluorescent Method ◽  
Derivatizing Agent

Herein, a novel fluorescent method for the determination of d-panthenol (DP) level in solutions with no separate hydrolysis step has been revealed based on the utilization of citric acid (CA) as a derivatizing agent. Consequently, the essential parameters of the derivatization process were established, resulting in the development of sensitive, repeatable, and accurate determination of panthenol. The method was approved, and its usefulness in characterizing the concentration of DP in pharmaceutical formulations and selectivity in the determination of DP were validated. The chemical structure of the new fluorophore formulating in the reaction in DP with CA, i.e., 6-oxo-3,4-dihydro-2H,6H-pyrido[2,1-b][1,3]oxazine-8-carboxylic acid (ODPC), was elucidated using detailed NMR experiments: one-dimensional (1H, 13C) as well as two-dimensional NMR spectra (1H-1H COSY, 1H-13C HSQC, 1H-13C HMBC, 1H-15N HSQC, 1H-15N HMBC).

Determination of Forchheimer Term in Porous Media Consisting of Obstacles of Different Sizes

2012 ◽  
Vol 594-597 ◽  
pp. 2537-2540
Author(s):  
Ren Xing Liu ◽  
Akira Nakayama ◽  
Xiao Lan Haung
Keyword(s):  
Porous Media ◽  
Numerical Models ◽  
Pressure Gradients ◽  
Two Dimensional ◽  
Reasonable Estimate ◽  
Pressure Drops ◽  
Pressure Fields ◽  
Definition Of ◽  
Average Size

As a sequel to the study in determining the permeability of the porous media composed of obstacles of different sizes, exhaustive numerical calculations were conducted using the same two-dimensional numerical models of square rods as in the previous study. The models consist of collections of square rod obstacles of two-, three-, four- and five-different sizes. Computations were carried out to reveal the details of microscopic velocity and pressure fields. There results are integrated to find the macroscopic pressure gradients for collections of multi-sized obstacles. The Ergun type general formula has been proposed along with a definition of an effective average size, which, when substituted into the formula, yields a reasonable estimate for the macroscopic pressure drops in multi-sized obstacles.

scholarly journals The New TLC Method for Separation and Determination of Multicomponent Mixtures of Plant Extracts

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Elżbieta Matysik ◽  
Anna Woźniak ◽  
Roman Paduch ◽  
Robert Rejdak ◽  
Beata Polak ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Gradient System ◽  
Two Dimensional ◽  
Phase Gradient ◽  
One Dimensional ◽  
Dominant Component ◽  
Phase Condition ◽  
Layer Chromatography

The new mode of two-dimensional gradient thin layer chromatography (MGD-2D TLC) has been presented. Short distance development of sample in the first dimension leads to formation of the preconcentrated narrow zones. They are consecutively separated in the second dimension with the mobile phase gradient in several steps of development until the eluent reaches the further end of the chromatographic plate. The use of the above-mentioned technique allows isolating and then identifying the compounds of various polarity from the multicomponent mixture. The practical application of two-dimensional gradient thin layer chromatography has been performed for isolation of the two plant (JuniperusandThymus) oils components as the examples of test mixtures. The experiments have been carried out with the use of silica gel plates as well as a normal phase condition. The results of solute separation with isocratic one-dimensional thin layer chromatography system have been compared with those of two-dimensional gradient system. It has been observed that application of the latter mode leads to almost triplicated number of zones in comparison with the former one. It is purposeful to apply the proposed mode to control the purity of the dominant component or components of the mixture.

scholarly journals Determination of the structure of a novel acidic oligosaccharide with blood-group activity isolated from bovine submaxillary-gland mucin

1989 ◽  
Vol 260 (2) ◽  
pp. 389-393 ◽  
Author(s):  
S M D'Arcy ◽  
C M Donoghue ◽  
C A M Koeleman ◽  
D H Van den Eijnden ◽  
A V Savage
Keyword(s):  
Blood Group ◽  
Submaxillary Gland ◽  
Two Dimensional ◽  
Methylation Analysis ◽  
One Dimensional ◽  
First Report ◽  
Novel Structure ◽  
Blood Group H

In this study we investigated the structure of an acidic fucose-containing pentasaccharide released from bovine submaxillary-gland mucin by alkaline-borohydride treatment. The structure, determined by a combination of one-dimensional and two-dimensional 1H-n.m.r. spectroscopy at 270 MHz and methylation analysis involving g.l.c.-m.s., was as follows: Fuc alpha(1-2)Gal beta(1-4)GlcNAc beta(1-3)[NeuAc alpha(2-6)]GalNAcol This pentasaccharide is a novel structure and is the first report of a blood-group-H type 2 determinant on a submaxillary-gland mucin.

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