section 4 Flashcards
two types of load
dynamic load - moving load e.g. book being dropped
static load - stationary load e.g. book on table
5 forces
tension - pulling force / resistance to stretching(tensile strength)
compression - squeezing/pushing force (compressive strength)
torsion - twisting force(torsion strength)
bending - results in compression and tension on either side of neural axis onto of fulcrum. (stiffness)
shear force - force that acts perpendicular to length of a body e.g. scissors on fabric
reinforcing materials
a way of strengthening materials by adding material to improves its ability to withstand force
how are car tyres reinforced
steel plates - reinforced tyre against punctures
side layering - sides of tyres ar layered to resist bumps and weight of car
reinforced concrete how is it better
steel grid placed win concrete. high compressive strength of concrete and bending strength of steel combines
reinforcement on clothes
metal rivets are placed onto areas where stitches combines to provide extra strength and tear resistance
webbing
fabrics are woven into strips from year providing very high strength. used for ppe like suspending ropes and seat belts
methods of stiffening materials
laminating - a paper is inserted into a plastic pouch with adhesive , making it more durable water resistant and less tear prone
interfacing - fabric is used to make garments more firm. e.g. baseball cap brim fusible or iron on garment is heat bonded and sew in is inserted into fabric with stitching
folding and bending - bending materials by adding curves arches can add considerable strength
nets and their features
nets are two dimensional layouts of a shape to be folded into 3d shapes. consist of :
cut lines - solid lines showing where the material is cut from
score-lines- weakened lines that are dotted or indented lines showing where to fold
tab - extra material that can be used to fold and hold the shape with glue
carbon footprint
a way of estimating greenhouse gases emissions caused by a product process or person
ecological footprint and how it coincides with carbon footprint
measures the impact of persons life on the natural environment by measuring how much natural resource they use
it is measured by the amount of co2 realised from their lifestyles, so it coincides with carbon footprint
social footprint
a measure of a companies impact on its community, policies, employees and partners by their social policies
how is safe and acceptable working conditions ensured in UK
the Health and Safety Execute are a group who make sure the Health and Safety at Work act(1974) is enforced.
the minimum wage is introduced in 1999 and is reviewed
companies can become fair trade recognised
slash and burn method of deforestation
forests are felled and then burnt. this provides nutrients to the soil for crops to be grown
desertification
when the land dries out after rainforests are felled and can no longer support life or vegetation
Mining and two types
mining is needed to extract material like minerals and metals that we need
underground mining - has less visual impact, is better for wildlife on earth but is dangerous for the miners and can cause sinkholes and instability
surface ming - scars the surface and environment more and causes more habitat loss
what is drilling and what it is needed for
drilling is used to extract oil and shale gas. a borehole is made at 2,000 metres and fuel is extracted but it needs to be stored in large areas or pipelines
farming effect on earth
uses large amount of land, so may aid deforestation. plants are generally carbon neutral but release carbon dioxide when decomposed or burnt as biofuel. cattle release methane.
product miles
a measure of how much transportation was required for a product to be made from all its components. this goes in the life cycle assessment and is a measure of co2 emissions
6 rs in order
refuse - not using or buying harmful things like plastic carrier bags or not eating overfished species
rethink - rethinking production and services as well as consummation to reduce emissions
reduce
reuse
repair
recycle
3 types of recycling
primary - reusing a product multiple times for the same purpose
secondary - reusing a product for another purpose
tertiary - actual recycling - least desirable as it can not be 100% efficient
4 scales of productio n
one off/ bespoke- made for one client with a specific characteristics
batch - more automation that one off, uses some specialist tools to make an identical number of products In a batch which may be altered each batch
mass - highly automated and high speed production lines for electronics
continuous - used to make stock form products and a limited range so production line does not have to be changed so it can run 24/7
