The US Department of Energy has announced $72m in funding for funding carbon capture technologies and $29m for fusion research projects.

On Wednesday, the department announced money for projects investigating two different areas of carbon capture.

within the first funding opportunity, nine new thermal power projects and industrial carbon sources will receive $51m for advancing carbon capture and storage (CCS).

This will involve testing engineering-scale technologies on flue gases from coal-fired and natural gas-fired power plants.

A further $21m is going to be split between 18 projects that specialize in capturing CO₂ directly from the air,

referred to as direct air capture.


These projects will specialize in developing and field-testing new materials used in direct air capture.

General Electric Research, Susteon, Innosense, and Electricore have each received many thousands of dollars

To develop different methods and sorbent materials for capturing CO2 from the air.

sorbent material

US Secretary of Energy Dan Brouillette said:

“The projects selected as a neighborhood of this research will help us develop the technological solutions needed to scale back greenhouse emission.

This is often critical to balancing our nation’s energy use while continuing to steer the planet in emissions reductions.”

Assistant Secretary for the Office of Fossil Energy Steven Winberg said:

“The primary mission of our office is to make sure that we can still believe its fuel resources for clean and secure energy.

The advancement of carbon capture technologies, including direct air capture, contributes there to the mission.

Our ultimate goal is to mature these technologies

In order to commercialize and delivered to the market.”

Fusion funds specialize in technologies surrounding the most reactor

The department also announced $29m for fusion technology advancements.

Fusion energy generation remains at an experimental stage, with research projects that specialize in consistently producing more energy

Than is required to start out the fusion process.

In a statement, the department said that while this has progressed,

“there remains a big got to specialize in the materials and enabling technologies which will be needed to determine fusion energy’s technical and commercial viability once net energy gain is achieved.”

The support will go toward 14 projects making advancements to technologies outside of this “fusion core”. This comes as a part of the Galvanizing Advances in Market-aligned fusion for an Overabundance of Watts (GAMOW) scheme.

The funded projects will cover three research areas. the primary of those covers the technologies, materials, and superconducting-magnet and fuel-cycle subsystems between the fusion plasma and balance of plant systems.

Oak Ridge National Laboratory received $8.65m for 3 projects, one among which can increase the warmth tolerance of materials in subsystems round the thermonuclear reactor.

Significant funding for US fusion research

The projects also will check out cost-effective, high efficiency, high-duty-cycle electrical driver technologies, also as those with more general applications, like new fusion materials, manufacturing processes, or scaling-up technologies.

The University of Houston has received $1.5m to continue its research into rare-earth metallic tapes. These could allow magnets infusion devices to become more powerful and cheaper to manufacture, lowering their cost by 30 times.

The Advanced scientific research Agency sponsors the GAMOW scheme.

Director Lane Genachowski said:

“Fusion energy may be a potentially game-changing clean energy source,

but for many years it faced scientific and technical challenges.

GAMOW teams will work to further develop enabling fusion materials and subsystem technologies, with attention on the timely future commercialization and deployment of fusion energy generation.”

International governments have collaborated on the ITER project in France, but some companies have started work on smaller reactors. In August, company Chevron invested in Zap Energy, which focuses on scalable fusion technology.



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Scientists had an equivalent reaction you almost certainly did once they reached this conclusion.

It should not be possible — in any case,

there is no oxygen on the moon, one among the 2 essential elements to make rust, the opposite being water.
But the evidence was there.

India’s lunar probe, Chandrayaan-1, orbited the moon in 2008, gathering data that has led to numerous discoveries

over the years — including the revelation that there are water molecules on its surface. The probe also carried an instrument built by NASA that would analyze the moon’s mineral composition.
When researchers at NASA and therefore the Hawai’i Institute of Geophysics and Planetology analyzed the info recently,

they were stunned to find hints of hematite,

a sort of iron oxide referred to as rust.


There are many iron-rich rocks on the moon

when the iron is exposed to oxygen and water to produce rust.

There’s a huge mass embedded within the center of the moon, and astronomers aren’t sure what it’s

“At first, I totally didn’t believe it.

It shouldn’t exist supported the conditions present on the Moon,” said Abigail Fraeman,

a scientist at NASA’s reaction propulsion Laboratory, during a handout.
Not only is there no air on the moon,

but it’s flooded with hydrogen that flows from the sun, carried by solar radiation.

Rust is produced

when oxygen removes electrons from iron; hydrogen does the other by adding electrons, which suggests it’s all the harder for rust to make on the hydrogen-rich moon.

“It’s very puzzling,” said Shuai Li of the University of Hawaii,

on Wednesday within the journal Science Advances. “The Moon may be a terrible environment for hematite to make in.”
After months of research, Li and therefore the NASA scientists think they’ve cracked it — and the answer to the mystery lies in our very own planet.

Here’s their theory

One major clue was the rust was more targeting the side of the moon that faces Earth

suggesting it had been somehow linked to our planet.

Earth is encompassed during a magnetic flux, and solar radiation stretches this bubble

to make an extended magnetic tail within the downwind direction.

The moon enters this tail three days before it’s full, and it takes six days to cross the tail and exit on the opposite side.
During these six days, Earth’s magnetic tail covers the moon’s surface with electrons, and everyone kind of strange thing can happen. Dust particles on the moon’s surface might float off the bottom, and moon dust might fly into a duster, consistent with NASA.
An enhanced map of hematite (dust) on the moon, shown in red employing aspheric projection of the nearside.

And, Li speculated, oxygen from the world travels on this magnetic tail to land on the moon, where it interacts with lunar water molecules to make rust.
The magnetic tail also blocks nearly all solar radiation during the complete moon

the moon is temporarily shielded from the blast of hydrogen, opening a window for rust to make.


“Our hypothesis is that lunar hematite is made through oxidation of lunar surface iron by the oxygen from the Earth’s upper atmosphere

that has been continuously blown to the lunar surface by solar radiation when the Moon is in Earth’s magnetotail during the past several billion years,” said Li during a handout by the University of Hawaii.
“This discovery will reshape our knowledge about the Moon’s polar regions,” he added. “Earth may have played a crucial role in the evolution of the Moon’s surface.”
A growing dent in Earth’s magnetic flux could impact satellites and spacecraft

on other airless bodies like asteroids. “It might be that tiny bits of water

therefore the impact of dust particles are allowing iron in these bodies to rust,” Fraeman said.

But some questions remain unanswered

where the Earth’s oxygen should not be ready to reach.

it is also still unclear how exactly water on the moon is interacting with the rock.
To gather more data for these unsolved mysteries,

NASA is building a replacement version of the instrument

that collected all this existing data about the moon’s mineral composition.

one among these features are going to be ready to map water ice

on the moon’s craters — and “may be ready to reveal new details about hematite also,” said the NASA release.






It was a feat for the ages. Just seven years before, a young president had challenged the state to land a person on the moon—not because it had been “easy,” as John F. Kennedy said in 1962, but because it had been “hard.” By July 20, 1969, Armstrong backed down a ladder and onto the moon’s surface.

Along the thanks to achieving JFK’s vision, there was much diligence, drama, and surprise. Here are some lesser-known moments throughout the epic U.S. effort to succeed in the moon.


1. Moon dirt smells.

A big question facing the NASA team planning the Apollo 11 moon landing was what would the moon’s surface be like—would the lander’s legs land on firm ground, or sink into something soft? The surface clothed to be solid, but the important surprise was that the moon had a smell.

Moon soil is extremely clingy and hard to ignore, so when Armstrong and Aldrin returned to the lunar excursion module and repressurized it, lunar dirt that had clung to the men’s suits entered the cabin and commenced to emit an odor. The astronauts reported that it had a burned smell like wet fireplace ashes, or just like the air after a fireworks show.

Scientists would never get the prospect to research just what the crew was smelling.

The moon soil and rock samples were sent to labs in sealed containers, once the pack was open on earth.smell  has gone

Somehow, as Charles Fishman, author of 1 Giant Leap, says, “The smell of the moon remained on the moon.”


2. JFK was more focused on beating the Soviets than in space.

In public, President John F. Kennedy had boldly pledged that the us would “set sail on this new sea because there’s new knowledge to be gained, and new rights to be won, and that they must be won and used for the progress of all people.”

But secret tapes of Kennedy’s discussions would later reveal that privately, JFK was less curious about space exploration than in one-upping the Soviets.

In a 1962 meeting with advisors and NASA administrators, JFK confessed, “I’m not that curious about space.” But he was curious about winning the conflict. Just months after JFK’s inauguration, the Soviet Union had sent the primary man into space. Kennedy asked his vice-chairman, Lyndon B. Johnson, how the U.S. could score a win against the Soviets.

One of the simplest ways to point out U.S. dominance, Johnson reported back, was by sending a manned mission to the moon. Johnson, in fact, had long been an area advocate, saying in 1958, “Control of space is control of the planet .”

3. The Soviets covered up their efforts to urge to the moon first.

It seems that the us wasn’t alone in eagerness to demonstrate its dominance by landing humans on the moon. The Soviet Union was also gunning to accomplish the feat. But once U.S. astronauts got there first, the Soviets tried to stay their efforts on the down-low.

4. Astronauts trained for microgravity by walking “sideways.”

How does one prepare to send someone to an area nobody has ever gone before? For NASA within the 1960s, the solution was to make simulations that mimicked aspects of what astronauts could expect to encounter.

Armstrong and Aldrin rehearsed collecting samples on fake, indoor moonscapes. Armstrong practiced beginning and landing within the Lunar Landing Training Vehicle in Houston. And, to simulate walking within the moon’s lower-gravity atmosphere, astronauts were suspended sideways by straps then walked along a tilted wall.

NASA and therefore the U.S. Geological Survey even blasted out craters at Cinder Lake, Arizona to make a landscape that matched a part of the moon’s surface—because, after all, practice makes perfect

5. Civil Rights activists got a front-row seat to the Apollo 11 launch.

Not everyone was gung-ho about the U.S. effort to land people on the moon. a couple of days before the scheduled launch of Apollo 11, a gaggle of activists, led by civil rights leader Ralph Abernathy, arrived outside the gates of the Kennedy Space Center. They brought with them two mules and a wooden wagon for instance the contrast between the gleaming white Saturn V rocket and families who couldn’t afford food or an honest place to measure.

Amid the heady build-up to the launch, the NASA administrator, Paine, came bent ask the protestors, face-to-face. After Paine and Abernathy talked for a short time under lightly falling rain, Paine said he hoped Abernathy would “hitch his wagons to our rocket, using the program as a spur to the state to tackle problems boldly in other areas, and using NASA’s space successes as a yardstick by which progress in other areas should be measured.”

Paine then arranged to possess members of the group to attend the subsequent day’s launch from a VIP viewing area. Abernathy prayed for the security of the astronauts and said he was as proud as anyone at the accomplishment.

6. Buzz Aldrin took communion on the moon.

When Apollo 11‘s Eagle lunar excursion module landed on the moon on July 20, 1969, astronauts Armstrong and Buzz Aldrin had to attend before venturing outside. Their mission ordered them to require an interruption before the large event.

So Aldrin used a number of the time doing something unexpected, something no man had ever attempted before. Alone and overwhelmed by anticipation, he took part within the first Christian sacrament ever performed on the moon—a rite of Christian communion.

7. Scientists have scared about space germs infecting Earth.

Armstrong, Aldrin, and Collin risk their lives for the advancement of humanity

They had the dubious pleasure of being quarantined for planetary protection.

Since humans had never been to the moon before,

NASA scientists couldn’t make certain that some deadly space-borne plague hadn’t hitched a ride on the astronauts.

The trio was transferred to a mobile quarantine facility on July 24,

when the re-enter to down to pacific

They were transported to NASA Lunar Receiving Laboratory at Johnson Space Center

To access a bigger quarantine facility until their release on August 10, 1969.

8. Nixon was anxious the mission could fail.

While Kennedy had rallied the state to land a person on the moon,

he was assassinated before he could see the Apollo mission achieve his vision.

That nerve-racking honor fell to President Nixon, who had been elected in 1968.

His staff had prepared a press release to be read within the event

the worst happened and arranged a priest to commit their souls to the deep, very similar to a burial stumped.

He didn’t. the lads who had traveled quite 200,000 miles to the moon

then stepped foot on an alien world had survived.

therefore the us would continue to finish six crewed missions

that landed a complete of 12 astronauts on the moon from 1969 to 1972.




Why we need magnetic refrigeration AND what is the magnetocaloric effect?

  • Magnetic cooling technology could make fridges and air conditioners quieter, safer, and more environmentally friendly. It might also help scientists run experiments at temperatures lower than the extreme chill of outer space without using expensive cryogenic liquids.
  • To avoid damage to the environment. Magnetic Refrigeration is an emerging, environment-friendly technology based on a magnetic solid that acts as a refrigerant by the magneto-caloric effect (MCE).

How does it work?

  • The magnetic refrigeration system works by applying a magnetic field to a magnetic material causing it to heat up.
  • The excess heat can remove by using water.
  • After cooling the material again come to the original temperature.
  • The material will demagnetised.

magnetic refrigeration

  • Magnetic cooling relies on materials called magnetocaloric, which heat up when exposed to a powerful magnetic field.
  • The conventional vapor compression system makes use of a compressor, two heat exchangers – an evaporator and a condenser, a throttling device.
  • The heat will converter into a vapor state in the evaporator
  • The vapor will enter into a compressor and increase the pressure and temperature
  • Then refrigerant will emits its heat into a condenser and will convert into a liquid in the magnetic system.
  • Then the throttling device will reduce the refrigerant pressure to the evaporator pressure.
  • The use of magnets, either permanent or superconducting, change occur in the magnetic field.
  • After that CFC or HFC refrigerant will convert into a working substance i.e. a magneto-caloric material.
  • Then the magneto-caloric effect will increase its temperature and the material will magnetize.

Magneto-caloric effect

  • The Magnetocaloric effect may be a magneto- thermodynamic phenomenon during which a reversible change in temperature of an appropriate material is caused by exposing the material to a changing magnetic flux.
  • this is often also referred to as adiabatic demagnetization magneto caloric effect
  • therein a part of the general refrigeration process, a decrease within the strength of an externally applied magnetic flux allows the magnetic domains of a selected (magnetocaloric) material to become disoriented from the magnetic flux by the agitating action of the thermal energy (phonons) present within the material.
  • If the fabric is isolated so that no energy is allowed to (e)migrate into the material during this point (i.e. an adiabatic process),
  • the temperature drops because the domains absorb the thermal energy to perform their reorientation.
  • The randomization of the domains occurs during a similar fashion to the randomization at the Curie temperature, except that magnetic dipoles overcome a decreasing external magnetic flux while energy remains constant, rather than magnetic domains being disrupted from internal ferromagnetism as energy is added.
  • one of the foremost notable samples of the magnetocaloric effect is within the element gadolinium and a few of its alloys.
  • Gadolinium temperature is observed to extend when it enters certain magnetic fields.manetic material
  • Gadolinium and its alloys are the simplest material available today for magnetic refrigeration near temperature 
  • since they undergo second-order phase transitions that haven’t any magnetic or thermal hysteresis involved.








why we need anti solar panel?

  • One of the problems with solar panels is that they don’t generate electricity at night
  • so we have to store the electricity they generate during the day to power things during the evening.
  • But what if we could develop solar panels that did generate electricity at night?
  • It is possible by anti solar panel.

what is anti solar panel?

anti solar panel

  • Anti solar panel is a panel that works in dark.
  •  To create a solar panel that generates electricity at night
  • Then you just have to create the exact opposite of solar panels work during the day.
  • It can be refer as“anti-solar panel.

How does it works?

  • There are different sorts of solar panels.
  • The one most typically used may be a type that generates electricity from the sun through a physical process called the photo-voltaic (PV) effect  i.e ,when light exposure on certain materials generates an electrical current.


  • Another type is to generates electricity from heat through thermal processes.
  •  The sun is hotter and Earth is cooler, and therefore the difference in temperature are often converted into usable energy.
  • That second quite solar battery is that the one that inspired a team of researchers at Stanford University in Palo Alto , California to develop a replacement system which can harness energy darkly .
  •  An inverse version of the solar battery also supports the concept of using heat to urge energy
  • While the solar battery uses the heat difference between the sun and Earth with the planet being the cooler side .

i.e,  system makes use of the heat difference between the coolness of the night atmosphere.

electricity generate at night

  •  thus the planet with the world being the hotter side.
  • The amount of power coming in, from the Sun . Approximately equal amount of power going out from the planet as thermal radiation,
  • so on stay the planet at a roughly constant temperature.
  • the number of power available for harvesting is extremely large.
  •  this device has the potential to bridge the gap left by solar energy , collecting energy from the night sky.


  • The thermoelectric generatorbased device harnesses the variance in temperature between Earth and space.
  • By using a passive cooling mechanism mentioned as radiative sky cooling to require care of the cold side of a thermoelectric generator several degrees below ambient.”
  •  the encircling air heats the great and comfy side of the thermoelectric generator, with the subsequent temperature difference converted into usable electricity.
  • We highlight pathways to improving performance from a demonstrated 25 mW/m2 to 0.5 W/m2.
  • Finally, we demonstrate that even with the low-cost implementation demonstration here, enough power is produced to light a LED: generating light from darkness.


  • if we can devise a system that can generate clean energy 24 hours a day, we could possibly produce more energy than we need and store it for various purposes, such as an emergency.
  • It’s better to have too much energy than to come up short
  • The researchers have only tested their system with a very small prototype.
  • The device was a 20-centimeter (8-inch) aluminum disk painted black and attached to commercial thermoelectricity generators.
  • It successfully created enough energy to power one small LED lightbulb–a small success with immeasurably massive potential.
  • It’s even possible that the device could act in reverse during the daytime, absorbing sunlight and producing electricity from a heat travelling from the sun to the disk and into the surface environment.

    This generator could produce power at nighttime or low-resource areas that lack electricity within the dark when solar panels don’t work.

  • For now, this device doesn’t compared to the energy harvesting abilities of a solar battery.
  • But the technology remains only within the research and development stage.
  • The researchers have already planned to improve .
  • By enhancing the insulation around the top plate that might  raise the energy of device to produce 0.5 watts per square meter or more.




A wind turbine converts the kinetic energy in the wind into mechanical power. We use a generator to convert mechanical energy in electricity.

  • Depending on the technology, the blades of the wind turbine turns revolution per minute.,at a variable velocity of the rotor.
  • whereas, velocity varies due to the velocity of wind in order to reach greater efficiency

Working and construction

wind turbine

  • Blowing air can turn the wings of turbine and electricity will generate from generator.

How does the blowing wind turns the wings?

  • The blade has a lots of airfoil cross section consisting of different size and shape from root to tip.
  • Airfoil technology make the wind turbine blades turn.
  • That means the  lift force is produced when a fluid moves over an airfoil.
  • In this way wind turbine receive a basic rotation .
  • The turning of wind turbine blade experience the wind relatively.(CONCEPT OF RELATIVE VELOCITY)

                             i.e V relative=V wind – V blade

  • Therefore,the wind turbine blade is position in a tilted mannered in order to align with the relative wind speed .
  • As the blade velocity increases to the tip the relative wind speed become more inclined towards the tip .
  • This means that a continous twist is given to the blade from root to tip.
  • However this rotation cannot be directly coupled to a generator.
  • because the wind turbine blades typically turns at a very low rate at rpm due to issue of noise and mechanical strength.
  • Considering this low speed rotation we cannot produce any meaningful electricity frequency from a generator .the speed is increases in gear box .
  • The gearbox use a planetary gear set arrangement to achive the high speed ratio.
  • A break also sits in a nacelle the function of brake is to arrested the wind blade rotation during excessively windy condition.
  • cut off speed≈ 80km/hr.
  • Consequently the electricity  is passed through the cable towards the base of step up transformer .
  • The wind turbine should face the wind normally for max. power extraction .
  • but wind direction can change at any time.
  • A velocity sensor on the top of the nacelle measure the wind speed and direction .
  • The deviation in the wind direction is sent to an electronic controller .Further, to correct the error ,the appropriate signal is send to yawing mechanism.
  • The yaw motor turn the nacelle
  • thus the turbine will always be align with the blow direction.
  • according to wind speed the relative velocity angle of the wind also changes
  • a blade tilting mechanism tilt the blade and guarantee a proper alignment of the blade with the relative velocity.
  • thus the blade are always at the optimum angle to attack with the relative wind flow.



What is carburetor?

What is carburetor?
  • The carburetor is the heart of ICE .
  • It is a device that mixes air and fuel for gasoline engine in the proper air–fuel ratio for combustion.

Working– TPS in BS carburetor to achieve:

1) smooth throttle response

2) Optimised fuel economy better fuel of power
  • It atomise the fuel and mix the fuel mix in form of the spray.
  • The Regulated mixture of air and fuel is send to cylinder for optimum burning.
  • The carburetor uses the principal of sprayer
  • When the piston  pushed inside, the velocity of air get increases and pressure get decreases at the outlet of reservoir .
  • The liquid in reservoir is at higher atmospheric pressure .This pressure difference results in the rising the liquid
  • The spray is used  in the air passage for air flow from air filter to engine .
  • The constriction at the centre of venturie .
  • The top of the constristion is at low pressure this causes the fuel to rise and it emerges from the top.
  • The fuel mixes with the top and the air fuel mixture is then send to engine
  • As the throttle open speed increase
According to the speed at which the vehicle is running the carburetor uses the appropriate circuit for the delivery of fuel .
1) Piston type throttle valve carburetor
  • In piston type throttle valve carburetor, piston valve controls the venturie size, which is directly operated by throttle cable.
2) Butterfly slide type throttle valve carburetor.
  • Butterfly valve is located after piston valve and shown by throttle cable.
  • When butterfly valve is open  the velocity of gas in passage increases due to the suction of engine and pressure drops at venturie area .
  • when the pressure drops in venturie the pressure in above chamber of the diaphragm also drop due to the hole provided in the Piston valve.
  • Because of  pressure difference between upper chamber and lower chamber ,  the Piston and jet needle get lifted up and align .
  • It is clear that the lifting of piston is controlled by the opening  of  butterfly slide valve

Instead of calculating why we not measure the stress?

Instead of calculating why we not measure the stress?


To check the temperature of water we need thermometer.

Ammeter used to measure the electric current,

Anemometer used to measure the wind speed,

Astrolabe used to measure the latitude and altitude of celestial body,

Audiometer used to measure the hearing purpose.

Instead of calculating why we not measure the stress?

Barometer used to measure the pressure,

there are to ways to  know the value of anything  i.e either you calculate or measure.

Like, In ancient time , instead of measuring we use to calculate the blood pressure of patient.

so from above , we can get the idea to measure the stress of  material  by using stress measuring device .

As we know , no practical possible without theory and theory based on observation.


stress measuring device can help to know about deformation occur on material by applying load at per unit area.

In engineering ,

stress is a internal resistive force to the deformation per unit area.






There are 3 type of stress ,

  • Tensile stress
  • Compressive stress
  • Shearing stress



So like that putting a theoretical formula and by designing and programming we can make stress measuring device.

Difference between the pressure and stress,


Normally , we say that” pressure is stress”

But its not like that , for any machine

stress is a internal resistive force to the deformation per unit area.

σ= applied load/cross section

unit – N/m²


Pressure is force per unit area.



Due to stress , the pressure will not develop .

But, Due to pressure the stress will develop

so we cannot say that pressure and stress and same .

So Basically the conclusion is pressure has measuring device ,but stress do  not have measuring device.

Although ,

we have stress measuring machine but not a stress measuring device.

S0, by using stress measuring device we can get the stress value of any material at any direction.










Maximum efficiency

Ideal engine has a maximum efficiency,

If a heat engine goes through fixed thermodynamics stage of a specificed process,



four main parts:η

  • Insulated – non conducting stand (the transfer of energy is not possible )
  • Hot reservoir– heat capacity should be infinite.

Because , After taking  any energy from it, the temperature of reservoir should be constant .

  • The reservoir in which infinite heat capacity will be conducting at high temperature is called to be cold reservoir.
  •  Cylinder  should be kept for working substances .

Cylinder wall should be non-conductive so that heat transfer is impossible .but base should be conducting .


For this , first place the cylinder on the hot reservoir since the temperature of reservoir is higher than the temperature of gas, the heat flows from the heat reservoir to the gas .Due to which the gas start to expands .

Since due to heat transfer gas is expanding therefore the temp of gas remain constant

This process is called Isothermal expansion.

as the gas expand , the volume of gas increase and pressure decrease .

In next step , take off the cylinder from the hot reservoir and place it on the insulating stand , when doing so, the gas is confined to the non-conducting wall.

Now let piston rise slowly upward .

Due  to which the gas continue to expand .But this time the gas is not getting any heat to expand .such expansion called Adiabatic expansion.

Since this expansion is taking place without heat .

The temperature of gas starts to decrease .Due to this expansion ,the volume of gas also increase and pressure decrease

In next step, lift the cylinder from the stand and place it on the cold reservoir , now pressure the piston downwards which causes compression of gas.

In this way the gas compresses at the same constant temperature .this called Isothermal compression

Due to this compression the volume of gas decreases and pressure increase

In final stage , cylinder keep on stand again and pressure piston downward

But now there is no cold reservoir to absorbs the heat getting produced extra.

Therefore , the temperature of gas start increase . this compression is called Adiabatic compression .

Pressure the piston until the temperature of gas rises back to equal that of the hot reservoir . This decrease the volume of the gas and increase the pressure

At the end of this step , the gas return to its initial stage .

This complete cycle is called the carnot cycle .The engine work on it ,is called carnot engine.

η =1-T1/T2

The efficiency depend on the temperature of both reservoir.

If  T1 is  ∞ kelvin and  T2 is 0 kelvin

Either rise the temperature of hot reservoir to ∞ kelvin or low down the temperature of reservoir to 0 kelvin .

In both cases,the efficiency will be 100%.