Definitions /Dictionary/Glossary - nptel

Laminated Plastics: Material consisting of superimposed layers of a synthetic resinimpregnated
or coated filler that has been bonded together usually by means of heat and
pressure, to form a single piece.
Laminate Ply: One layer of a laminated product.
Land: The portion of a mold which provides the separation or cutoff of the flash from the
molded article; in the screw of an extruder, the bearing surface along the top of the flights; in an
extrusion die, the surface parallel to the flow of material; in a semi-positive or flash mold, the
horizontal bearing surface; in a two-piece mold, a platform build up to the split line.
Lap: In filament winding, the amount of overlay between successive windings, usually intend to
minimize gapping.
Lap Joint: A joint made by bonding overlapped portions of two adherents.
Lay: In glass fiber, the spacing of the roving bands on the roving package expressed in the
number of bands per inch; in filament winding, the orientation of the ribbon with some reference,
usually the axis of rotation.
Lay-up: A process of fabrication involving the assembly of successive layers of resinimpregnated
material.
Layer: A single ply of lay up or laminate.
Leader: The low luminosity, low current precursor of a lightning return stroke, .accompanied by
an intense electric field.
Lengthwise Direction: Refers to the cutting of specimens and to the application of loads. For
rods and tubes, lengthwise is the direction of the long axis. For the other shapes of materials that
are stronger in one direction than in the other, lengthwise is the direction that is stronger. For
materials that are equally strong in both directions, lengthwise is an arbitrarily designated
direction that may be with the grain, direction of flow in manufacture, longer direction, etc.
Lightning Attachment Point: Any spot where the lightning flash attaches to the aircraft.
Lightning Channel: The ionized path through the air along which the lightning current pulse
passes.
Lightning Flash: The total lightning event. It may occur within a cloud, between clouds or
between a cloud and ground. It can consist of one or more return strokes, plus intermediate or
continuing currents.
Lightning Strike: Any attachment of the lightning flash to the aircraft.