Two-dimensional power-type electronic spectrographs with a symmetry plane

2011 ◽  
Vol 56 (6) ◽  
pp. 843-849 ◽  
Author(s):  
N. K. Krasnova
Keyword(s):  
Symmetry Plane ◽  
Two Dimensional ◽  
Power Type

The Lekhnitskii Formalism

1996 ◽  
Author(s):  
T. T. C. Ting
Keyword(s):  
Symmetry Plane ◽  
Stroh Formalism ◽  
Two Dimensional ◽  
Elastic Materials ◽  
Engineering Community ◽  
Anisotropic Elastic

A two-dimensional deformation means that the displacements ui, (i= 1,2,3) or the stresses σij depend on x1 and x2 only. Among several formalisms for two-dimensional deformations of anisotropic elastic materials the Lekhnitskii (1950, 1957) formalism is the oldest, and has been extensively employed by the engineering community. The Lekhnitskii formalism essentially generalizes the Muskhelishvili (1953) approach for solving two-dimensional deformations of isotropic elastic materials. The formalism begins with the stresses and assumes that they depend on x1 and x2 only. The Stroh formalism, to be introduced in the next chapter, starts with the displacements and assumes that they depend on x1 and x2 only. Therefore the Lekhnitskii formalism is in terms of the reduced elastic compliances while the Stroh formalism is in terms of the elastic stiffnesses. It should be noted that Green and Zerna (1960) also proposed a formalism for two-dimensional deformations of anisotropic elastic materials. Their approach however is limited to materials that possess a symmetry plane at x3=0. The derivations presented below do not follow exactly those of Lekhnitskii.

Visualization and Analysis of Flow in an Offset Channel

1992 ◽  
Vol 114 (4) ◽  
pp. 819-826 ◽  
Author(s):  
J. A. Walter ◽  
C.-J. Chen
Keyword(s):  
Reynolds Number ◽  
Velocity Field ◽  
Nuclear Power ◽  
Flow Direction ◽  
Symmetry Plane ◽  
Two Dimensional ◽  
Plant Design ◽  
Duct Flow ◽  
Inlet Channel ◽  
Cross Sectional

This paper investigates flow characteristics for a benchmark experiment that is important for thermal hydraulic phenomena in nuclear power plant design. The flow visualization experiment is carried out for flow in a rectangular offset channel covering both the laminar and turbulent flow regimes. The Reynolds number, based on the inlet velocity and the height of the inlet channel, ranges from 25 to 4600. The offset channel is an idealized thermal hydraulic geometry. Duct flow expands in a rectangular chamber and exits to a duct that is offset from the entrance duct. The offset geometry creates zones of recirculation for thermal-hydraulic mixing. Flow patterns are visualized by a laser light sheet in the symmetry plane of the primary flow direction and in three cross-sectional planes. A charge-coupled device (CCD) images the flow field, simplifying the experimental process and subsequent image analyses. The flow pattern and size of the recirculation zones change dramatically with Reynolds number until the flow is fully turbulent. While the velocity field itself is predominantly two dimensional, it is shown that the walls of the chamber produce a fully three-dimensional flow that could not be predicted properly by a two-dimensional calculation. Quantitative measurements of particle pathlines from several images are superimposed to give a composite view of the velocity field at one of the Reynolds numbers examined.

A Two-Dimensional Model of Predicting Sand Erosion in Elbows for Liquid Flow

2017 ◽  
Author(s):  
Rong Kang ◽  
Haixiao Liu ◽  
Mingyang Liu
Keyword(s):  
Penetration Depth ◽  
Liquid Flow ◽  
Symmetry Plane ◽  
Sand Particle ◽  
Mass Force ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Particle Trajectories ◽  
Sand Erosion ◽  
Two Dimensional Model

A two-dimensional theoretical procedure is proposed in this study to estimate sand particle erosion in 90-degree elbows for liquid flow. The two-dimensional model adequately describes the erosion occurring along the centerline of the elbow extrados and to an extent reflects the erosion level on the whole elbow. The sand erosion prediction procedure is divided into three steps: building a two-dimensional liquid flow model, tracking the particle trajectories and predicting the penetration depth. First, a motion expression of the fluid streamline in an elbow is deduced from the continuity equation and the Euler equations, supposing the incompressible flow in the elbow is steady and inviscid. The radial velocity is introduced into the present model to reflect the effect of secondary flow on the symmetry plane. Second, particle trajectories are computed using the Lagrange approach based on the obtained expression of flow field distributions. The effects of the fluid drag force and the virtual mass force are considered as the main factors, and the particle impact velocity and angle are predicted through this method. Third, the penetration depth can be calculated from erosion correlations and the erosion profile along the centerline of the 90-degree elbow can also be worked out. Several typical experiments are selected to verify the two-dimensional theoretical model by comparing the predicted erosion results with the measured data.

Homogenization of Rough Two-Dimensional Interfaces Separating Two Anisotropic Solids

2011 ◽  
Vol 78 (4) ◽  
Author(s):  
Pham Chi Vinh ◽  
Do Xuan Tung
Keyword(s):  
Explicit Form ◽  
Symmetry Plane ◽  
Homogenization Method ◽  
Two Dimensional ◽  
Linear Elasticity Theory ◽  
Practical Applications ◽  
Component Form ◽  
The Matrix ◽  
Straight Lines ◽  
Dimensional Domain

In this paper we have derived homogenized equations in explicit form of the linear elasticity theory in a two-dimensional domain with an interface highly oscillating between two straight lines, by using the homogenization method. First, the homogenized equation in the matrix form for generally anisotropic materials is obtained. Then, it is written down in the component form for specific cases when the materials are orthotropic, monoclinic with the symmetry plane at X1=0 and X2=0. Since these equations are in explicit form, they are significant in practical applications.

scholarly journals On the Fluid Dynamical Effects of Synchronization in Side-by-Side Swimmers

Biomimetics ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 77 ◽  
Author(s):  
Ramiro Godoy-Diana ◽  
Jérôme Vacher ◽  
Veronica Raspa ◽  
Benjamin Thiria
Keyword(s):  
Particle Image ◽  
Phase Synchronization ◽  
Swimming Performance ◽  
Symmetry Plane ◽  
Water Tank ◽  
Two Dimensional ◽  
Kinematic Parameters ◽  
Image Velocimetry ◽  
Coherent Jet ◽  
Flexible Foils

In-phase and anti-phase synchronization of neighboring swimmers is examined experimentally using two self-propelled independent flexible foils swimming side-by-side in a water tank. The foils are actuated by pitching oscillations at one extremity—the head of the swimmers—and the flow engendered by their undulations is analyzed using two-dimensional particle image velocimetry in their frontal symmetry plane. Following recent observations on the behavior of real fish, we focus on the comparison between in-phase and anti-phase actuation by fixing all other geometric and kinematic parameters. We show that swimming with a neighbor is beneficial for both synchronizations tested, as compared to swimming alone, with an advantage for the anti-phase synchronization. We show that the advantage of anti-phase synchronization in terms of swimming performance for the two-foil “school” results from the emergence of a periodic coherent jet between the two swimmers.

Spectrophotometric measurements of objective-prism spectra

1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Progress Report ◽  
Two Dimensional ◽  
Objective Prism ◽  
Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

Analysis of the 9th November 1990 flare

2000 ◽  
Vol 179 ◽  
pp. 229-232
Author(s):  
Anita Joshi ◽  
Wahab Uddin
Keyword(s):  
Image Processing ◽  
Two Dimensional ◽  
Temporal Behaviour ◽  
Contour Maps ◽  
Dimensional Measurements ◽  
Processing Software ◽  
Image Processing Software

AbstractIn this paper we present complete two-dimensional measurements of the observed brightness of the 9th November 1990Hαflare, using a PDS microdensitometer scanner and image processing software MIDAS. The resulting isophotal contour maps, were used to describe morphological-cum-temporal behaviour of the flare and also the kernels of the flare. Correlation of theHαflare with SXR and MW radiations were also studied.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

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