Transcript UNIT 2 CLASSIFICATION

UNIT 7
Vocabulary
• Conventional Power Plants:
– Thermal power plant
– Nuclear power plant
– Hydroelectric power plant
Grammar and functions
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Describing processes: sequence (p122)
Active vs. Passive
Revision of vb tenses (regular & irregular vbs)
Revision of grammar structures
SEQUENCE (p122)
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First / Firstly / First of all / The process begins /commences / starts with
In the first step / stage / The first step / stage is .... / To begin with
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Secondly/ After this, / Later, / Afterwards/ Then, / Next, / Subsequently
In the following / next stage, / The next step is ...
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At the end of the process / In the last stage/ The last step / stage is ....
Finally / Eventually.. finishes / concludes with
So far, / Up to now
Before this / Previously, / Prior to this / Earlier, / In the preceding / previous
/ former stage
• At the same time,/ During .... / Simultaneously, / While ... / Meantime /
Meanwhile / As ... / In the meantime / When ...
OTHER EXPRESSIONS
• The process takes place / occurs / happens
• To carry out / develop a process
METHOD: by means of ... / (by) using ... / With the help of ...
• One method for /way of ... (+ verb –ING) .... is to ....
PURPOSE: In order to, so as to, to + INF
• This ALLOWS / CAUSES it TO occur // PREVENTS it FROM occurring
TRANSLATION
• GREAT/LARGE AMOUNTS OF ELECTRICITY CANNOT BE
GENERATED UNLESS ) a coil rotates in a magnetic field
• that IS DONE BY MEANS OF/WITH A TURBINE connected to a generator
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The turbine converts the kinetic or thermal energy of a flowing fluid INTO useful
rotational energy
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A generator contains the stator, WHICH IS THE MAGNET and a rotor, WHICH
IS THE COIL
• WHEN/AS THE ROTOR TURNS the wires cut the lines of force in the magnetic
field of the stator
• PRODUCING AN ALTERNATING CURRENT
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The enormous size of modern generators and the speed AT WHICH the rotor can
turn mean that electric power of very high voltage can be produced
• AS MUCH AS HALF A MILLION VOLTS can be transmitted over high voltage
lines to substations
• IN WHICH THE VOLTAGE IS REDUCED WITH / BY (MEANS OF THE
USE OF) USING TRANSFORMERS
TRANSLATION
• The rotor is turned BY/ BY MEANS OF / WITH a turbine,
• a huge machine moved by water or STEAM IN POWER PLANTS
• ACCORDING TO/DEPENDING ON THE SOURCE OF ENERGY USED
to move the turbine
• By far, the most important sources of power are those produced by
THE CHEMICAL ENERGY OF/FROM FOSSIL FUELS, LIKE/SUCH
AS OIL OR COAL , nuclear energy and the potential energy of
waterfalls.
• Fossil-fueled power plants contain a boiler WHICH WORKS LIKE a big
kettle.
• AFTER BEING HEATED (UP) TO A CERTAIN TEMPERATURE, the
steam is passed through small holes, increasing the speed of the water
molecules
• The fast moving molecules hit the blades of the turbine and MAKE IT
(THEM) TURN .
VIDEO: Coal PP (Utube 0-1:50)
1. Where is half of world’s electricity generated? In coal power plants
2. How many are there in the world? Close to 3,000 large coal PP
3. How this controversial yet indispensable PP works, i.e. how to convert the
energy stored in the COAL to ELECTRICITY
4. To increase burning efficiency a POWDERED COAL and air MIXTURE
enters the furnace
5. During the burning process the chemical energy stored in the coal is
released as heat to create high temperatures inside the furnace.
6. This heat passes to the water inside the coils located in the furnace.
7. The hot water is then forced to move to the boiler where it evaporates and
generates high-pressure steam.
8. The high-pressure steam is taken to the steam turbine
9. The energy inside the steam is converted into mechanical energy.
10. This mechanical energy is then transferred to the generator where it will
be converted into electricity
11. The generated electricity is finally transferred to the grid through a
transformer and is ready to be consumed by the public
ACTIVE vs PASSIVE
Passive voice:
• The agent (doer) of the action is NOT IMPORTANT or UNKNOWN
• To EMPHASIZE the first part of the sentence
• Typical VOICE in TECNICAL ENGLISH, particularly when describing
processes.
The pyramids were built thousands of years ago.
The samples were analysed in the laboratory
The mixture is fed into the pulveriser.
NOTE:
- Some verbs have NO PASSIVE (intransitive, impersonal) = e.g. RAIN,
AGREE, APPEAR, ARRIVE, OCCUR, HAPPEN, BECOME, RISE,
BELONG, CONSIST (of), DEPEND, EXIST, DIE, FALL, LIVE, WAIT,
HAVE, modals (CAN, MAY, MUST)
– Be careful with Spanish expression “se + vb”:
e.g. se lava las manos = he washes his hands;
los polos se atraen = the poles attract each other
The reaction spreads out very quickly
- Placement of SUBJECT: (with vbs like THINK, BELIEVE, CONSIDER,
ESTIMATE, REQUEST …)
- The atom was thought to be the smallest particle;
- Students are requested to register in the university website;
- Renewable energy is believed to be the answer to climate change
PASSIVE VOICE
TO BE (changing verb) + Past Part of MAIN VERB.
The system …..
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PRESENT = IS
PRESENT CONT= IS BEING
PAST = WAS (WERE)
PRESENT PERFECT = HAS (HAVE) BEEN
+ DEVELOPED
PAST PERFECT = HAD BEEN
WITH MODAL VB = CAN/MUST BE
WILL / SHOULD = BE
GERUND = BEING
PAST PARTICIPLE = BEEN
•AGENT = BY (por) = The system was developed BY the engineers of the plant
• if an object = BY / BY MEANS OF / USING / WITH = The system was
developed BY MEANS OF / USING a new technique
VERB TENSES
Nuclear energy is the energy RELEASED through the fission
or fusion of atomic nuclei.
In the process KNOWN AS nuclear fusion two light atoms join
together UNDER conditions of extreme HEAT and
PRESSURE (at LEAST 50,000,000 degrees Celsius) until
they merge, forming a new nucleus WHOSE mass is only
slightly smaller THAN the total masses of the nuclei that
FUSE together.
The opposite process is nuclear FISSION which MEANS
“splitting apart” or “dividing”.
If either nuclear fusion or fission TAKES place quickly, the
result is a sudden release of ENERGY but so far the only
one THAT can BE SLOWED down and CONTROLLED is
fission.
VERB TENSES
• However, only a few elements are suitable FOR use.
• When one of THESE elements is STRUCK by a free neutron,
IT SPLITS / BREAKS/ IS BROKEN down INTO two lighter
nuclei, WHICH fly apart AT high speeds, colliding WITH
surrounding atoms.
• This kinetic energy IS CONVERTED INTO heat.
• AT the same time, two or three more neutrons ARE
RELEASED and one of THEM enters the nucleus of a
neighbouring atom, causing fission TO OCCUR again,….
• The reaction SPREADS very quickly with more and more
energy RELEASED.
• This IS REFERRED to as A “chain” reaction because the
splitting of each nucleus IS LINKED to another.
VERB TENSES
• If this reaction IS UNCONTROLLED, the result is an
atomic explosion like THAT/THE ONE CAUSED by the
atomic bombs of Hiroshima and Nagasaki.
• However, the reaction can BE SLOWED down and that
is WHAT happens in a nuclear reactor or pile.
• Here the highly fissile material IS SURROUNDED BY a
substance that is non-fissile, FOR instance, graphite.
• This material IS CALLED A moderator.
• The neutrons LOSE some of THEIR energy through
COLLIDING with the atoms of the moderator and no
expansion IS PRODUCED .
• by SLOWING down the speed of the free neutrons, IT
makes it …. collide WITH the nucleus of a neighbouring
atom to continue the chain REACTION
VERB TENSES
• The major advantage of nuclear energy is that it DOES
NOT DEPEND ON any local factors.
• A nuclear reactor, UNLIKE conventional power plants,
DOES not have TO BE BUILT near a fossil-fuel source,
nor does it depend ON a large flow of water WHICH may
BE REDUCED during some seasons of the year.
VERBS (regular&irregular)
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TO DRAW
DREW DRAWN
TO SPREAD
SPREAD SPREAD
TO RAISE
RAISED
TO BUILD
BUILT BUILT
TO SPEND
SPENT SPENT
TO FIND
FOUND FOUND
TO MAKE
MADE MADE
TO SUPPLY
SUPPLIED
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TO THROW
THREW THROWN
TO WRITE
WROTE WRITTEN
TO RISE
ROSE RISEN
TO HOLD
HELD HELD
TO BREAK
BROKE BROKEN
TO PUT
PUT PUT
TO BRING
BROUGHT BROUGHT
TO GIVE
GAVE GIVEN
VERBS (regular&irregular)
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TO TAKE
TOOK TAKEN
TO SPLIT
SPLIT SPLIT
TO WIND
WOUND WOUND
TO FEED
FED FED
TO SET
SET SET
TO DRIVE
DROVE DRIVEN
TO ALLOW
ALLOWED
TO FLOW
FLOWED
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TO KNOW
KNEW KNOWN
TO SHOW
SHOWED SHOWN
TO LEAVE
LEFT LEFT
TO STRIKE
STRUCK STRUCK
TO LET
LET LET
TO SEE
SAW SEEN
TO CUT
CUT CUT
TO LEAD
LED LED
VIDEO: Nuclear reactor
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URANIUM
the exact SIZE that is USED in the fuel rods.
This TINY pellet CONTAINS more ENERGY than 6 car loads of coal.
We have 20 MILLION of these pellets INSIDE the reactor vessel.
We call it the CORE.
Around the core, of course, there is WATER.
WATER is used as a COOLANT.
Now, … another set of rods called the CONTROL RODS.
These rods actually control the NUCLEAR REACTION.
What happens is this: …. that is when it is ACTIVATED,
with them gone, the NUCLEAR FUEL sets up a CHAIN REACTION
that PRODUCES a tremendous AMOUNT of HEAT,
that BOILS the WATER,
that turns to STEAM,
that TURNS the TURBINE,
that turns the GENERATOR, that PRODUCES ELECTRICITY.
GRAMMAR REVISION: THE NUCLEAR REACTOR
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… place IN which a fission NUCLEAR reaction TAKES place.
It contains …in THE form of rods to produce the appropriate result.
The reactor consists OF a fuel, a moderator and A cooling system.
An instrument …neutron WHICH strikes the nucleus of an atom of
U-235.
The nucleus … which collide WITH other nuclei and split, and so on.
However, if no explosion occurs IT is because …is moderated BY a
non-fissionable material such AS graphite or heavy water.
This absorbs most OF the free neutrons and prevents them FROM
splitting too MANY nuclei too quickly.
The process releases great AMOUNTS of energy in the form of
heat.
This heat ….produced can be USED to generate electric power.
As the fuel … during ITS use inside the reactor, when IT is taken
…, IT is stored in the fuel pools, …, in general more THAN a year,
before sending IT to the processing plant.
LISTENING: comparison of fuels
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about different fuels and processes. We’ve been told that nuclear power is
more efficient than conventional fossil fuels and we know that fossil fuels
are limited.
-Conventional fossil fuels, i.e., oil, coal and gas, and nuclear fuels, i.e.,
uranium and plutonium.
-different nuclear reactors and different conventional processes.
-Say a bucket holds 10 kg
Let’s look at the 2 million Kw power station.
2 million kw make 2,000 megawatts
That’s nuclear fuel
which converts all the matter in this fuel into energy.
it may last 8 ½ years. In fact, ….. with the hydrogen fusion reactor.
Only two weeks
- The next process is a fast reactor. …. natural uranium.
After three days. Now let’s look at conventional fossil fuels, shall we? ….
One hour?
-it will last 1/18th of a second. And the same goes with coal.
-In Europe, France, and then West Germany.