Research on the added mass of open-type one-way tensioned membrane structure in uniform flow

2015 ◽  
Vol 137 ◽  
pp. 69-77 ◽  
Author(s):  
Zhaoqing Chen ◽  
Yue Wu ◽  
Xiaoying Sun
Keyword(s):  
Membrane Structure ◽  
Added Mass ◽  
Uniform Flow ◽  
Open Type

Panel method predictions of added mass for flexible airship

2013 ◽  
Vol 117 (1191) ◽  
pp. 519-531 ◽  
Author(s):  
M. Zhang ◽  
X. Wang ◽  
D. Duan
Keyword(s):  
Membrane Structure ◽  
Dynamic Models ◽  
Mass Matrix ◽  
Added Mass ◽  
Panel Method ◽  
Arbitrary Geometry ◽  
State Equations ◽  
Ellipsoid Of Revolution ◽  
And Control ◽  
Manipulation And Control

Abstract Because of the huge volume and inflated membrane structure of stratosphere airship, the deformation of stratosphere airship is very sensitive to the change of environment conditions such as wind, temperature and so on. The influence of deformation on manipulation and control is very remarkable. So, during the course of building flight dynamic model of the flexible airship, the added-mass matrix of deformation is very important part in the state equations of dynamic models. For obtaining the accurate added-mass matrix of different flexible airship, we proposed an approach that can calculate the added-mass matrix of a flexible airship with arbitrary geometry shape by the panel method. Through the comparison of results of computation and theory for ellipsoid of revolution and the flexible Skyship-500 airship, the proposed method can calculate the added-mass matrix for arbitrary geometric shape very accurately.

Axisymmetric bubble or drop in a uniform flow

1981 ◽  
Vol 108 ◽  
pp. 89-100 ◽  
Author(s):  
Michael Miksis ◽  
Jean-Marc Vanden-Broeck ◽  
Joseph B. Keller
Keyword(s):  
Constant Velocity ◽  
Weber Number ◽  
Reynolds Numbers ◽  
Added Mass ◽  
Terminal Velocity ◽  
Bubble Surface ◽  
Uniform Flow ◽  
Axially Symmetric ◽  
Maximum Value ◽  
Nonlinear Integrodifferential System

The deformation of an axisymmetric bubble or drop in a uniform flow of constant velocity U is computed numerically. The flow is assumed to be inviscid and incompressible. The problem is formulated as a nonlinear integrodifferential system of equations for the bubble surface and for the potential function on the surface. These equations are discretized and the resulting algebraic system is solved by Newton's method. For U = 0 the bubble is a sphere. The results show that as U increases the bubble becomes oblate, spreading out in the direction normal to the flow and contracting in the direction of the flow. Then the poles get pushed in and ultimately they touch each other. The results also show that there is a maximum value of the Weber number above which there is no steady axially symmetric bubble. This value is somewhat smaller than the approximate value obtained by Moore (1965) but close to that found by El Sawi (1974). We also compute the added mass, the drag on the bubble, and its terminal velocity in a gravitational field, for large Reynolds numbers.

scholarly journals Aero-elastic behavior of open-type one-way tensioned membrane structure models

AIP Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 105201
Author(s):  
Zhaoqing Chen ◽  
Liang Yin ◽  
Lixiang Tang ◽  
Shuang Wang
Keyword(s):  
Membrane Structure ◽  
Elastic Behavior ◽  
Open Type

Bimolecular and Monomolecular Lipid Films: Selected Area Electron Diffraction

1969 ◽  
Vol 27 ◽  
pp. 338-339
Author(s):  
Robert M. Glaeser ◽  
David W. Deamer
Keyword(s):  
Electron Diffraction ◽  
Membrane Structure ◽  
Molecular Organization ◽  
Membrane Material ◽  
X Ray Diffraction ◽  
Membrane Systems ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Lipid Films ◽  
Ultimate Objective

In the investigation of the molecular organization of cell membranes it is often supposed that lipid molecules are arranged in a bimolecular film. X-ray diffraction data obtained in a direction perpendicular to the plane of suitably layered membrane systems have generally been interpreted in accord with such a model of the membrane structure. The present studies were begun in order to determine whether selected area electron diffraction would provide a tool of sufficient sensitivity to permit investigation of the degree of intermolecular order within lipid films. The ultimate objective would then be to apply the method to single fragments of cell membrane material in order to obtain data complementary to the transverse data obtainable by x-ray diffraction.

Cellulose Acetate Reverse Osmosis Membrane Structure

1972 ◽  
Vol 30 ◽  
pp. 528-529
Author(s):  
H. K. Plummer ◽  
E. Eichen ◽  
C. D. Melvin
Keyword(s):  
Cellulose Acetate ◽  
Reverse Osmosis ◽  
Membrane Structure ◽  
Freeze Drying ◽  
Dense Layer ◽  
Water Removal ◽  
Reverse Osmosis Membrane ◽  
Correct Interpretation ◽  
Electron Image ◽  
Scanning Electron

Much of the work reported in the literature on cellulose acetate reverse osmosis membranes has raised new and important questions with regard to the dense or “active” layer of these membranes. Several thickness values and structures have been attributed to the dense layer. To ensure the correct interpretation of the cellulose acetate structure thirteen different preparative techniques have been used in this investigation. These thirteen methods included various combinations of water substitution, freeze drying, freeze sectioning, fracturing, embedding, and microtomy techniques with both transmission and scanning electron microscope observations.It was observed that several factors can cause a distortion of the structure during sample preparation. The most obvious problem of water removal can cause swelling, shrinking, and folds. Improper removal of embedding materials, when used, can cause a loss of electron image contrast and, or structure which could hinder interpretation.

Warm and freeze-fracture of cotton seed radicles

1987 ◽  
Vol 45 ◽  
pp. 984-985
Author(s):  
E. L. Vigil ◽  
E. F. Erbe
Keyword(s):  
Thin Film ◽  
Water Vapor ◽  
Fracture Surface ◽  
Membrane Structure ◽  
Room Temperature ◽  
Freeze Fracture ◽  
Longitudinal Axis ◽  
Fracture Plane ◽  
Cotton Seeds ◽  
Condensed Water

In cotton seeds the radicle has 12% moisture content which makes it possible to prepare freeze-fracture replicas without fixation or cryoprotection. For this study we have examined replicas of unfixed radicle tissue fractured at room temperature to obtain data on organelle and membrane structure.Excised radicles from seeds of cotton (Gossyplum hirsutum L. M-8) were fractured at room temperature along the longitudinal axis. The fracture was initiated by spliting the basal end of the excised radicle with a razor. This procedure produced a fracture through the tissue along an unknown fracture plane. The warm fractured radicle halves were placed on a thin film of 100% glycerol on a flat brass cap with fracture surface up. The cap was rapidly plunged into liquid nitrogen and transferred to a freeze- etch unit. The sample was etched for 3 min at -95°C to remove any condensed water vapor and then cooled to -150°C for platinum/carbon evaporation.

The ultrastructure of the double membrane-bound bodies and endoplasmic reticulum in serial sections of wheat spot mosaic-affected wheat plants

1990 ◽  
Vol 48 (3) ◽  
pp. 694-695
Author(s):  
M. H. Chen ◽  
C. Hiruki
Keyword(s):  
Endoplasmic Reticulum ◽  
High Resolution ◽  
Membrane Structure ◽  
Mosaic Disease ◽  
Serial Sections ◽  
Thin Sections ◽  
Double Membrane ◽  
Southern Alberta ◽  
Membrane Bound ◽  
Scanning Em

Wheat spot mosaic disease was first discovered in southern Alberta, Canada, in 1956. A hitherto unidentified disease-causing agent, transmitted by the eriophyid mite, caused chlorosis, stunting and finally severe necrosis resulting in the death of the affected plants. Double membrane-bound bodies (DMBB), 0.1-0.2 μm in diameter were found to be associated with the disease.Young tissues of leaf and root from 4-wk-old infected wheat plants were fixed, dehydrated, and embedded in Spurr’s resin. Serial sections were collected on slot copper grids and stained. The thin sections were then examined with a Hitachi H-7000 TEM at 75 kV. The membrane structure of the DMBBs was studied by numbering them individually and tracing along the sections to see any physical connection with endoplasmic reticulum (ER) membranes. For high resolution scanning EM, a modification of Tanaka’s method was used. The specimens were examined with a Hitachi Model S-570 SEM in its high resolution mode at 20 kV.

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