HSC Engineering In depth

Body centred cubic

A type of crystal structure in metals. This structure can be seen as a gathering of cubes with atoms at the edges and an atom in the center of every cube.

Cast Iron

Iron carbon that is hard, brittle and weak in tension.

Solute

dissolves in solvent

Austenite

FCC, appears at 1000 degrees, 2% carbon

limestone

formed when shells and other plant and animal matter are subjected to extreme heat and pressure

Clays

Chemical weathering of silicate minerals with water

Polymerisation

a chemical reaction joining monomers in long chains to form a polymer.

addition polymerization

a type of polymerization in which the monomers simply add together to form the polymer, with no other products

Boundary layer

The point on the surface with a layer of air next to the wing

Transition point

When the air on the boundary layer becomes turbulent

Equation of continuity

A1V1=A2V2

mean camber line

An imaginary line between the leading and trailing edges and halfway between the airfoil's upper (curved) and lower (flat) surfaces

Elevators

the hinged rear section of the horizontal stabilizer as part of the tailplane

concentration cells

occurs when there is a difference in concentration of electrolyte

VR of a bicycle

diameter of pedal/ Diameter of wheel x Number of revolutions(teeth front/teeth rear)

Copper zinc alloy as connectors

harder and stronger than pure copper, while having good corrosion resistance they will however tarnish. Can be plated to resist conductivity issues caused by oxidation

Geostationary Satellite

a satellite that orbits above the equator and is commonly used to broadcast TV signals

Vitrification

the process that is applied to dried clay for it to obtain the required compressive strength for use as a common brick (firing)

Amorphous

Random and non crystalline atomic structure.

Asphalt

Composite material of aggregate in a matrix of bitumen.

Truss

supportive structure consisting of beams or girders in triangular formation

Yield point

The first point at which the specimen yields and increases stain occurs without an increase in stress

Yield strength

the ability to bear gradual progressive force without permanent deformation

Hydraulic cements

hardened when mixed with water

pre-stressed concrete

Concrete is preloaded with stresses to help strengthen it for tensile loads

Post-tensioned concrete

primary reinforcement is tensioned after concrete placement and cure

compression moulding

The manufacturing process generally used for processing thermosetting polymers.

Bernoulli's Principle

as the velocity of a fluid increases, the pressure exerted by the fluid decreases

Critical Mach number

the speed where airflow reaches the speed of sound

Disc Brake

A brake in which pressure squeezes the brake pads against a flat metal wheel disc, producing the friction needed to stop the wheel from turning.

VA of a pulley system

= number of ropes across

Diode and transistor

electronic components semi-conductors

Drag and thrust

the forces oppose each other during level flight

Face centred cubic

A cubic lattice with the face positions fully equivalent to each of the eight corners.

Elastic limit

the maximum extent to which a solid may be stretched without permanent alteration of size or shape.

Aerofoils

a structure with curved surfaces designed to give the most favourable ratio of lift to drag in flight, used as the basic form of the wings, fins, and tailplanes of most aircraft.

Stiffness

the ability to resist defamation under stress

Total Thrust

F1 + F2

Basic oxygen steel making

High purity oxygen is blasted through the molten scrap to aid oxidation and remove impurities as part of steel recycling.

Cantilever

Beams anchored at only one end.

Cement

Constituent of concrete made from a mixture of clay and lime like materials.

Ceramic

Multi phase material containing compounds of metals and non-metals, typically hard and good insulators.

Composites

Multi-phase materials formed from a combination of materials with different compositions or forms. These combinations improve upon the original properties of the constituent materials.

Compression

Squashing or clamping force.

Concrete

Cement, sand, aggregate and water chemically bonded over time, good in compression but poor in tension without steel reinforcement.

Corrosion

The deterioration or breakdown of a material brought about by its interactions with the environment that cause chemical change.

Elastic

Deforms under stress but returns to the original shape when the stress is released.

Factor of safety

Guides engineers to design structures within safe limits.

Fatigue

A cyclic load with the force often well below the yield strength.

Geotextile

Natural and synthetic materials used to create a barrier between different materials in contact with the earth; can be porous or impermeable.

Glass

A ceramic produced through a fusion of inorganic materials cooled to a solid state with an amorphous structure.

Hooke's law

Stress is directly proportional to strain.

Life cycle analysis

A tool used to assess the impact a product or process has on the environment.

Plasticity

The ability to resist permanent deformation without failure

Shear

Cutting force in which parallel internal surfaces slide past each other.

Strain

The amount of deformation an object experiences compared to its original length.

Stress

The relationship between a force and the a materials cross sectional area (N/mm2 or MPa).

Superstructure

Includes roadways, footpaths, railing and supporting structural members of a particular structure.

Tension

Stretching or pulling force.

Timber

A naturally occurring composite made up of cellulose and lignin.

Ultimate tensile strength

The maximum stress a material can withstand before failure.

Wrought iron

Iron and large inclusion of slag (stony waste) elongated by the forming process

Yield stress

The maximum stress in MPa at which permanent, non elastic deformation will occur.

Young's modulus

The ratio of stress to strain with the elastic region.

Allotropic

different atom arrangements based on temperature

Intrinsic semiconductor

Non- doped semiconductor

Extrinsic

Doped semiconductor

Amplitude modulation

Encodes a radio carrier wave by varying its amplitude

Amplifier

A device which boost a signal

Attenuation

the reduction in amplitude of an electrical signal

Bandwidth

The amount of data transfer in a given period of time

Carrier wave

an electromagnetic wave that can be modulated in frequency or amplitude

Channel

Any path a communication may take from a transmitter to receiver

Conductor

A substance, body or device capable of transmitting electricity, heat, sound, etc.

Conductivity

The ease that free electrons in a material move.

Diode

an electric component that allows current to flow in one direction only

Direct wave

An electromagnetic wave that travels from transmitter to receiver by line of sight

Dispersion

Act or process of scattering light, electricity or waves.

Fibre optics

The transmission of light signals via fibre optics

Fidelity

The degree at which an electronic system accurately reproduces the sound or image of its input signal

Frequency modulation

Encodes a radio wave by varying its frequency

Brittle

easily cracks

Creep

permanent deformation when subjected to prolonged stress

Ductile

able to be drawn into thin wires or deformed without losing toughness

Elasiticty

being able to return to their original shape after being deformed

Hardness

the ability to resist permanent change by force, scratching

Malleability

being able to be rolled into thin sheets

Resilience

the ability to obsorb energy and resist soft impact loads

Toughness

amount of energy required to break it

Elements

most basic of matter and cannot be broken down

Solution

result of solvent and solute mixing

Solvent

able to dissolve other substances

Compounds

are two or more elements that are bonded chemically in a fixed proportion

Mixture

are two or more substances (elements of compounds) mixed together mechanically in a random proportion

Biological materials

a result of the life cycle of a plant or animal

Composite materials

materials combined together to capitalise on their desireable properties

Alloys

mixtures of two or more metals

Thermosetting polymer

non reversible with links between polymer chains, high tensile strength

Thermosoftening polymer

reversible when heated, malleable, recyclable

Tensile strength

ability to withstand a stretching force