SHAPE DESIGN OF MEMBRANE STRUCTURE USING GEOMETRIC INVARIANTS OF DISCRETE SURFACE

Maintaining surface accuracy is crucial to realizing the required performance of membrane structure. However, compressive stress inevitably leads to wrinkling, and the accurate analysis of the stresses becomes significant. The present study analyzed membrane structures with discrete loads. First, a simple method was proposed and the stress field was accurately described using an Airy stress model. The first and second principal stresses were obtained, and regions of wrinkling with negative stress were predicted. Second, for a square membrane structure, vertical tensions around the boundary were applied such that in-plane stresses were more evenly distributed. Finally, to reduce the wrinkling areas more effectively, an arc-edge structure was designed by removing some areas of low-stress. Simulation results showed that the in-plane stress field distribution was described accurately and the wrinkling regions were diminished effectively with the proposed method.

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Shape Design of Curved Surface of Membrane Structure Using Developable Surface

Journal of the International Association for Shell and Spatial Structures ◽

10.20898/j.iass.2018.197.005 ◽

2018 ◽

Vol 59 (3) ◽

pp. 199-214

Author(s):

Jinglan Cui ◽

Makoto Ohsaki

Keyword(s):

Membrane Structure ◽

Curved Surface ◽

Shape Design ◽

Developable Surface

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Bimolecular and Monomolecular Lipid Films: Selected Area Electron Diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063603 ◽

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.

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Cellulose Acetate Reverse Osmosis Membrane Structure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095893 ◽

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.

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Warm and freeze-fracture of cotton seed radicles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100129206 ◽

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.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161023 ◽

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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Computational Micrograph Registration with Sieve Processes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100164660 ◽

1996 ◽

Vol 54 ◽

pp. 440-441

Author(s):

P.J. Phillips ◽

J. Huang ◽

S. M. Dunn

Keyword(s):

Planar Graph ◽

Efficient Algorithm ◽

Spatial Organization ◽

Spatial Arrangement ◽

Stereo Image ◽

Image Model ◽

Geometric Invariants ◽

Point Set

In this paper we present an efficient algorithm for automatically finding the correspondence between pairs of stereo micrographs, the key step in forming a stereo image. The computation burden in this problem is solving for the optimal mapping and transformation between the two micrographs. In this paper, we present a sieve algorithm for efficiently estimating the transformation and correspondence.In a sieve algorithm, a sequence of stages gradually reduce the number of transformations and correspondences that need to be examined, i.e., the analogy of sieving through the set of mappings with gradually finer meshes until the answer is found. The set of sieves is derived from an image model, here a planar graph that encodes the spatial organization of the features. In the sieve algorithm, the graph represents the spatial arrangement of objects in the image. The algorithm for finding the correspondence restricts its attention to the graph, with the correspondence being found by a combination of graph matchings, point set matching and geometric invariants.

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