Chemistry Reference
In-Depth Information
tanning, mineral
A process for making
leather
by treating animal
skins
with
mineral
salts
such as
alum
.
tanning, oil
A process for making
leather
, by treating animal
skins
with animal
oil
or oily materials derived mainly from fish or marine animals.
tanning, vegetable
The process for making
leather
by treating animal skins with
tannins
derived from plants.
tanning agent
See
tannin
.
tapa
A
nonwoven fabric
used for writing in the South Pacific Ocean islands; it is made
from the bark of mulberry trees, of the botanical genus
Morus
.
taphonomy
Study of the processes that affect the remains of living organisms from
the moment of death until they become
fossilized
; see
biostratinomy
and
diagenesis
.
tarnish
A form of
decay
of the exposed surface of some
metals
, such as copper and
silver, when they interact with
sulfur
compounds (usually
sulfides
) in the envi-
ronment that is accompanied by changes in the
color
of the surface.
tattoo
An implantation under the skin of a
pigmented
indelible design, usually of a
decorative or symbolic nature.
tawing
A very ancient
mineral tanning
process in which use was made of
alum
and
common salt
.
teasel
The prickly flowerhead of plants of the family
Dipsacaceae
or a wire device,
used to raise a
nap
on
textile fabrics
.
teaseling
A process for making
textile fabrics
soft and rise a
nap
on their surface with
a
teasel
.
TEM
Acronym for
transmission electron microscope
.
temper
An inert
material
added to
ceramic bodies
to alter their
plasticity
and
firing
properties; also known as
additive
,
inclusion
,
filler
, and
grog
, as well as
aplastic
,
non-
plastic
,
nonclay
, or
opening material
.
temperature
A measure of the average energy of
atoms
and
molecules
; the higher the
temperature, the more energy the particles have.
tempering
(1) A
thermal process
for softening hard and brittle
steel
by heating it to
a given temperature, usually within the range 150-650°C, and then cooling at an
appropriate rate; (2) in
ceramic
technology, the addition of
temper
to
clay
when
preparing a
ceramic body
.
template
(1) A pattern or gauge; (2) in
molecular biology
, a
molecule
(e.g., of
DNA
)
that serves as a pattern for the generation of another molecule (of
RNA
in the
example above).
tephra
General term for
mineral
grains of all sizes ejected into the atmosphere
during volcanic eruptions and deposited on the surface of the earth.
tephrochronology
Study of
tephra
deposits to determine their
age
and age
relationships.
terracotta
A type of
pottery
, generally
unglazed
, made from
clay
and coarse
tempers
and generally
fired
at temperatures well below 900°C.
