DT Unit 2 Flashcards
(88 cards)
1
Q
How are fossil fuels formed?
A
Fossil fuels are formed from the fossilized remains of plants and animals over millions of years.
2
Q
What is fracking?
A
Fracking involves drilling into layers of shale rock deep in the earth to release pockets of gas.
3
Q
what are the renewable alternatives to fossil fuels?
A
-wind
-solar
-tidal
-biomass
-hydroelectric
4
Q
what are the arguments FOR wind power?
A
- low maintenance
- clean energy
-higher winter output
-low cost energy
5
Q
what are the arguments AGANIST wind power?
A
-only works when windy
-can be an eyesore
-hazards to birds
- noise
6
Q
what are the arguments AGANIST solar power?
A
-seasonal fluctuations
- no power generated at night
-complex positioning issues
7
Q
what are the arguments FOR solar power?
A
-low maintenance
- clean energy
-relatively low cost
8
Q
What is tidal energy?
A
the rise and fall of the tide forces water through turbines which drives generators to produce electricity.
9
Q
what are the arguments FOR hydroelectric power?
A
- clean source of energy
- it always ready to use (flexible)
- relatively inexpensive
10
Q
what are the arguments AGANIST hydroelectric power?
A
- it has an environmental impact
- limited locations
-Susceptible to Droughts
11
Q
what are the arguments AGANIST biofuel/ biomass?
A
- expensive
- requires a lot of space for technology
- still releases greenhouse gases
12
Q
What are the arguments FOR biofuel/biomass?
A
- its a widely available energy source
- less garbage in landfills
- reduces the reliance on fossil fuels
13
Q
What are the arguments FOR nuclear power?
A
- produces carbon free electricity
- cheap to run nuclear power stations
- high power output
-reliable energy source
14
Q
what are the arguments AGANIST nuclear power?
A
- radioactive waste
- risk of accident
- initial expensive cost to build
15
Q
What is energy?
A
energy is the capacity to do work
16
Q
what are the two forms of energy?
A
- potential energy (stored)
- kinetic energy ( motion)
17
Q
what’s an example of potential energy?
A
- chemical
- mechanical
- nuclear
- gravitational
18
Q
What’s an example of kinetic energy (motion)
A
- movement
- electricity
- heat
- sound
19
Q
what is potential energy?
A
potenial enrgy is stored in objects not in motion, that will move once released.
20
Q
What is kinetic energy?
A
kinetic energy involves movement
21
Q
how is energy stored?
A
- mechanical storage
. compression
. tension
.motion - chemical storage
. batteries
. food
. solid fuel
. gases
22
Q
what are pneumatics?
A
compressed air or gas is used to create movement.
commonly used in industry with mechanical drills
23
Q
what are hydraulics?
A
pumped and compressed liquids instead of air which makes it more powerful.
commonly used in:
-lifting equipment
24
Q
what is flywheel energy storage?
A
- they use surplus energy to reach optimum speed
- momentum is stored until it is required
- the motor used to power them becomes a generator which returns electrical energy when needed
25
Examples of chemical energy storage includes:
- batteries
- canisters
- flammable gels
- hydrogen fuel cells
26
what are alkaline batteries?
there more efficient and have a higher capacity when compared to traditional batteries
27
what examples are there of new emerging battery technology?
- flow batteries (they are large units used to help smooth demand on the national grid)
-sodium and glass batteries are super fast charging and very high capacity.
28
disposal of batteries:
batteries contain toxic chemicals and metals which can leach into the soil and harm the wildlife.
you can safely dispose of batteries by recycling them
29
What are modern materials
new and improved materials are constantly being discovered and developed.
They can help solve:
-design issues
-technical constraints
- environmental issues
extra point: they can also be or combined in a way that is different from its normal function.
30
what is a biodegradable polymer?
They are made from vegetable starches, often corn starch.
Ex: polylatic acid (PLA) commonly used in 3D printing filament.
31
What is titanium?
A chemical element which is often bonded/ alloyed with other metals.
- It is relatively lightweight, tough, low density.
- excellent corrosion resistance making it very versatile
32
What are fibre optics?
fibre optic cables carry light down a thin glass core.
ex: cable TV and broadband infrastructure
33
What are the physical properties of graphene?
- one atom thick
- 200x times stronger than steel
-stretchable and flexible
- electrically conductive
34
what is a LCD?
Liquid crystal displays (LCDs) use the light-modulating. properties of liquid crystals to display an image
35
What is metal foam and what is it used for?
Metal foams are porous metal structures made from aluminium and titanium. They are strong, lightweight, electrically & thermally conductive and absorb sound well. They are made by injecting gas into the liquid metal but still retain many properties of the original metal including being recyclable
36
What is a smart material?
smart materials react to an external stimulus by changing their characteristics or properties.
37
What is the self - healing polymer?
- self -healing polymers react to stress fractures by releasing resin into the new crack.
38
how does self healing concrete work?
- cracks enlarge over time and water can cause the steel reinforcements to rust and weaken the structure
- self healing concrete has spheres of bacteria added to the mixture which contains their own food.
- when the crack forms and water seeps in, the bacteria start to feed, producing calcium carbonate which fills the crack.
39
what are thermochromic pigments?
when hot and cold temperatures trigger a change of colour.
40
what are photochromic pigments?
Photochromic pigment is a specialty designed powder to change color when exposed to a UV light source,
41
Shape memory alloy (SMA)
Shape-memory alloys (SMA) are metal alloys. that can remember their shape when heated.
42
what is quantum tunnelling composition?
QTC is a polymer that contains billions of metal particles that don't actually touch each other.
43
how do piezoelectric materials work?
- subject it to movement or stress and it produces electricity
- attach an electrical signal and it moves
44
what is a piezo transducer?
A piezoelectric sensor changes mechanical motion or force into electrical energy and can produce an electrical pulse from pressure. EX: used in mobile phones
45
How can PH levels be detected?
Using litmus paper
46
What is a composite material?
A composite material. consists of two or more materials. with different properties.
47
What are the two types of reinforced plastic?
- glass reinforced plastic (GRP)
- carbon fibre reinforced plastic (CFRP)
48
what is the GRP process?
1. prepare the mould
2. apply a release agent to the mould
3. apply a gel coat for GRP
4. apply glass fibre matting
5. work a second coat of resin into the material
6. repeat layers of matting and resin coats to
achieve the correct thickness for the specification
7.clamp and leave a GRP workpiece to cure ( seal a GRP workpiece in a vacuum bag and heat in an oven to cure)
8. release from the mould, trim and finish workpiece.
49
what are technical textiles?
These are textiles that have had their fibres spun in a way that makes them enhanced fabrics.
50
what is gore-tex?
it is a technical textile.
It has a special fabric membrane that is waterproof yet breathable.
It doesn't let water through because the water droplets are too big but perspiration can still escape as water vapor.
51
What are aramids?
aramids are particularly tough fibres made from modified polyamide.
they offer:
- cut and tear resistance
- flame proofing
- thermal insulation
- high strength
- kevlar and nome are both types of aramids.
52
what is microencapsulation?
- solids, liquids, gases are sealed in tiny capsules and only under active ingredients they can be released at controlled rates and under controlled conditions.
Active ingredients include:
. thermochromic dyes
. pesticides
. perfume
53
what is an electronic system?
an electronic system is a series of pastor components that control a task or activity.
54
what are subsystems?
they are events that happen within an electronic system. Ex: steering
55
What is an open loop system?
Open-loop systems do not make a decision based on feedback.
56
What are closed loop systems?
feedback is used to make a decision
57
what are flowcharts?
flowcharts are a more detailed way to graphically represent systems.
58
What are input components?
- systems and devices are triggered either or automatically using switches and sensors.
59
what are analogue inputs?
analogue components give out varying signals. Ex; a dark street lamp needs to be turned on in the evening. The dark detector uses a variable resistor which allows the sensor to detect change.
60
What are output components?
output components change electrical energy into light, sound, heat an movement.
61
what is a integrated controller ( IC)
- also known as microchips, ICs are capable of performing specific tasks
62
what is a microcontroller IC?
a microcontroller IC is known as a peripheral interface controller (PIC)
- these programmable ICs are very adaptable
- they can be programmed to perform multiple processes
- this reduces the amount of components needed to perform a task
63
How is a PIC's functions controlled?
By a program or code that is received via a download cable
64
what is a monostable device?
a single pulse produced is usually triggered by a switch or sensor
65
what is an astable device?
the stream of pulses produced are oscillating and constant
66
what is motion?
motion is the action of something being moved
67
what is linear motion?
movement in one direction along a straight line
68
what reciprocating motion?
a receptive back and forth-or up and down linear action
69
what is oscillating motion?
a repetitive back and forth motion along a curve path
70
what is rotary motion?
objects moving in a circular motion usually around a fixed axis
71
what two parts do levers have?
a bar and a pivot also known as the fulcrum
72
what is the equation for levers?
MA= load/ effort
73
describe where the load, fulcrum and effort is on a first-order lever?
the load on the far left, the fulcrum in the middle (underneath) and effort on the far right
example of a first-order lever: seesaw
74
describe where the load, fulcrum and effort is on a second-order lever?
the effort is on the far left, the load is on the middle, the fulcrum is underneath and on the far right.
example: wheelbarrow action
75
describe where the load, fulcrum and effort is on a third-order lever?
the load is on the far left, effort is in the middle and the fulcrum is on the far right.
example: tweezers
76
what is equilibrium?
when the effort and the load are equal , the equilibrium can be reached in a mechanism.
77
what is a linkage?
linkages are mechanisms that use rigid parts to:
- change the magnitude of a force
- change the direction of a force
- transform it into a different motion
78
what is a reverse motion linkage?
( a Z shape) with a fixed pivot in the middle and moving pivots going opposite ways.
79
what is the parallel motion linkage?
two vertical parallel fixed pivots with a moving pivot across the top.
also a input on the left and a output on the right.
80
bell crank linkage.
a fixed pivot the shape of the 90-degree angle with a moving pivot on the left and the bottom moving in a circular motion
81
what is the crank and slider
crank and sliders convert rotary motion into reciprocating motion and vice versa
82
what are treadle linkages
treadle linkages convert rotary motion into oscillating motion and vice versa
83
what do rotary systems do?
rotary systems drive mechanisms in machinery and equipment
84
what are the 4 types of cams?
eccentric cam
pear cam
snail cam
heart- shaped cam
85
what are the 3 types of followers?
flat follower
knife edged follower
roller follower
86
what are gear trains?
cogwheels are meshed to create gear trains
87
what is an idler gear?
an idler gear ensures that the direction of the drive gear and the driven gear are the same
88
what are block and tackle systems?
they combine pulleys to lift heavy weights
