Nonmetals In The Plant Flashcards
A liquid has a fixed volume but it’s shape can change
True
The density of a liquid is measured in
Mass unit per unit of volume. In the us we use lb/ft^3
Water 62.4
Evaporation is a form of what?
It is a form of vaporization. During evaporation, molecules with enough energy escape from the surface of the liquid evaporation and it is also a cooling process
How is density (mass per unit of vol.) measured in gases?
It is measured in fractions of a pound per cubic foot.
What is laminar flow?
Laminar flow is when a fluid moves in layers parallel to the pipe
Can gasses dissolve in liquids?
Yes they can but the solubility decreases as the temperature rises. This solubility is usually 0 at the boiling point of the liquid.
Describe thermoplastics.
Thermoplastics soften when heated and harden when cooled, they can be reheated and reshaped many times
In regards to molding plastics what is one of the most widely used processes?
Injection molding is the most widely used. It is high speed and low cost for forming intricate parts.
What is filament winding in regards to reinforcing plastic?
Filament winding is used on tanks and containers that require high strength and are resist to corrosion. A continuous strand of resin coated glass fibers wound around a special form called a mandrel.
How should you drill in plastics?
You should drill for short periods of time to allow the part to cool. To avoid chipping and cracking reduce the feed rate just before the drill point penetrates the other side.
What should you do when reinforcing, coating, or patching corroded surfaces on plastic.
Remove as much as the damaged area as possible. Use a sanding disk to remove rough material. Clean both sides of the material with solvent to remove oils and dirt
Elastomers have the ability to be stretched to least _______ their original length and then _______________.
Twice
Return rapidly to its original shape.
What class of rubber resists damage by extreme high and low temperatures.
Class T rubbers
Most rubber compounds can burn.
True
Describe vulcanizing and the products that come from it.
The process of adding sulfur to rubber and then heated. The more sulfur added the harder the rubber. Soft rubber has less than 4% sulfur
Which rubber insulation cables do you certainly want to have flexibility?
Extension cords, welding cable, and power tool cords
What is a radial cut for lumber?
A radial cut is produced by cutting a log lengthwise, with the cut going through or near the centerline of the log.
Lumber is also sold by the board foot.
True
What is the rating for the best veneers from the plywood faces?
Class N. Very natural look not many knots,
Is lumber with many knots well suited for load bearing structures?
No the knots weaken the wood.
Describe using pilot holes in softwoods.
The hole should be smaller than the treads and only half the screw length
Describe air entrained concrete.
It is concrete that has tiny air bubbles distributed throughout the material. For building exposwd to severe cold.
Concrete block is used for construction below ground level. What kind if block is used for above ground construction?
Cinder block
Describe type N mortar.
Medium strength used for exposwd masonry above ground. Also used for load bearing clay tile construction.
Describe plaster of paris.
Sets very quickly, within 15 min. So it can only be used on small patching jobs
Heat is transferred by convection in fluids.
True
In regards to insulation, describe mineral wool as an insulator.
It has a low k factor, will not burn, stands bith high and low temperatures. Used in ovens, boilers, hot water heaters. Freezers.
How can excessive vibration be reduced between machinery and its piping.
It can be reduced by wrapping pipes or ducts with lead sheet or plastic film containing lead powder.
An asphalt coating serves as a moisture barrier on the outside of underground or basement walls.
True
Mica is the best insulating material.
Liquid part of paint is also known as the ______.also know as a binder becaise it binds the pigment particles into a uniform film
Its called the vehicle.
Surface preparation is the single most important factor for success in applying a protective coating.
True
In regards to sand blasting, white blasting cleanse a surface to the barometer. It completely removes all scale and corrosion and creates the best anchor of pattern.
True
In regards to safety colors what does green Represent?
They usually represent safety showers 1st aid stations 1st aid kits gas masks safety instruction signs stretchers
In metallizing, and oxyacetylene flame mouth the zinc and sprays in it on to the substrateIn metallizing, and oxygen a settling flame mouth the zinc and sprays in it on to the substrate.
True
On the PH scale, Numbers above 7 indicate alkalinity. Numbers below 7 indicate acidity.
True
Why should gasoline never be used for cleaning?
Because it is highly flammable.
What is sulfamic acid is also used for?
Used for removing hard water deposits in heating and cooling systems.
In water treatment, separators or stabilizers, called sequestrants do what?
They prevent scale (stone like material from hard water) and piping systems and boilers.
And at least in terms, what is curing?
It is the completion of all chemical and physical reactions that affect bonding.
What are water soluble gums and starches from plants made into?
Natural vegetable glues called mucilage.
High temperature tapes are coated with fluorocarbon Orange silicone infectives and used where service conditions include high temperatures as in the draft chamber of a chimney
True
What are the properties of carbon?
Withstands high temperatures
Chemically innert at low temperatures.
Carbon combines with oxygen more rapidly as temperatures increase, but it is chemically inert at room temperature.
True
