Prrodn vlknov kompozity

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Prírodní vláknové kompozitypevnost a ohebnost
vlákenných svazku

• David Luká
• Alberts B. Základy bunecné biologie, Espero
  Publishing, Ústí nad Labem, 1997

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Celulosa
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Figure2. Colocalisation of cortical microtubules
(green) with the CesA protein IRX3 (red) in
developing xylem vessels of the Arabidopsis root.
Colocalisation of IRX3 with microtubules give the
characteristic orange colour.
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The orientation of cellulose microfibrils within
the plant cell wall influences the direction in
which the cell elongates.
Microtubules direct the deposition of cellulose
in the plant cell wall.
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One of the most important distinguishing features
of plant cells is the presence of a cell wall.
The relative rigidity of the cell wall renders
plants sedentary, unlike animals, whose lack of
this type of structure allows their cells more
flexibility, which is necessary for locomotion.
The plant cell wall serves a variety of
functions. Along with protecting the
intracellular contents, the structure bestows
rigidity to the plant, provides a porous medium
for the circulation and distribution of water,
minerals, and other nutrients, and houses
specialized molecules that regulate growth and
protect the plant from disease.
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Kolagen, collagen
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Collagen from a Mouse Heart
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cytoskeleton
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On uniqueness of fibrous materials
Ning Pan Fiber and Polymer Science Division
ofTextiles and Clothing Biological and
Agricultural Engineering Department University
ofCalifornia
 
One of the main features making fibrous
structures the top choice in many applications
has to do with its bending flexibility while
still maintaining high tensile stiffness and
strength
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The difference lies in the deformation mechanism.
In a rope under bending or shearing load,
individual fibers in the rope will slide or move
over each other, given rooms for individual
fibers to bend into desired shapes. In other
word, the fiber is bent in respect to its own
axis of radius r whereas in the rod, the bending
rigidity is much greater because of the greater
diameter or bending moment of inertia.
Rod I ..Bending moment r Rod radius
R
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The rod of equal mass (cross-section)
A rope of N fibres