Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
15 Cards in this Set
- Front
- Back
|
anizotropic
|
=wood exhibits different physical properties (strength, shrinking, swelling, compression) when tested along 3 tree directional axes
|
|
|
properties characteristic of certain species only
|
variation between woods in:
a. specific gravity b. hardness c. strength properties d. mashining e. gluing f. durability g. reaction to chemicals |
|
|
which factors determine the properties of wood?
|
a. growth
b. structure c. composition of the material |
|
|
3 surfaces of wood
|
a. transverse (cross-sectional) surface is used the most
b. tangential surface c. radial surface |
|
|
cross section of a wood fiber (inside to out)
|
a. lumen
b. secondary wall c. primary wall d. middle lamella |
|
|
what is the distribution of content of wood
|
cellulose (40-50%)
hemicellulose (20-30%) lignin (15-30%) |
|
|
properties common to all woods
|
a. all tree stems have a predominately vertical arrangement of cells
b. all wood is cellular in structure c. all wood contains cellulose, hemicellulose, and lignin d. all wood is anizotropic e. all wood is hygroscopic |
|
|
what is the result of moisture variations?
|
- it produces dimensional changes which are due to its anisotropic nature, unequal in the n= three tree directions
|
|
|
why is it relevant to distinguish between certain species?
|
-must have positive identification as a basis for its manufacturing, marketing, and proper use
|
|
|
3 tree directional axes
|
a. radial
b. tangential c. longitudinal |
|
|
why is understanding the properties of wood important?
|
-to utilize the wood correctly
|
|
|
which wood fibers are on average longer, softwoods (coniferous) or hardwoods (deciduous)
|
softwoods (coniferous)
|
|
|
variablity within a species
|
a. variablity from tree to tree
b. variability in wood taken from different places c. variability within a given piece of wood (early or late wood) |
|
|
what are the fundamental studies of wood
|
a. properties that are common to all woods
b. properties that are characteristic only to certain species c. degree of variability of properties that may be present within a species |
|
|
hygroscopic
|
=wood loses and gains moisture as a result of changes in the atmospheric humidity and temperature
|
