For most of
our history, human technology consisted of our brains, fire, and sharp sticks.
While fire and sharp sticks became power plants and nuclear weapons, the
biggest upgrade has happened to our brains. Since the 1960’s, the power of our
brain machines has kept growing exponentially, allowing computers to get
smaller and more powerful at the same time. But this process is about to meet
its physical limits. Computer parts are approaching the size of an atom! To
understand why this is a problem, we need to clear up some basics.
Quantum
computer is that computer which does its entire works using quantum mechanics.
It uses Entanglement, Teleportation, and Superposition etc to compute or
exchange information. Quantum computers can do such things that cannot be done
using normal computers. But the fact is, Quantum computer cannot still be developed
in the laboratory.
 |
| Quantum Computer |
A computer is made up of very simple
components doing very simple things. Representing data, the means of processing
it and control mechanisms. Computer chips contain modules, which contain logic
gates and transistors. A transistor is a simplest form of a data processor in
computers. Basically, it’s a switch that can block, or open the way for
information coming through. This information is made up of bits which can be set
either 0 or 1. Combinations of several bits are used to represent more complex
information. Transistors are combined to create logic gates which still do very
simple stuff. For example, an AND gate sends an output of 1 if all of its
outputs are 1, and an output of 0 otherwise. Combination of logic gates finally
forms a meaningful module, for adding two numbers. Once you can add you can
also multiply, and once you can multiply you can basically do anything. Since
all basic operations are literally simpler than fist grade math, you can
imagine a computer as a group of little kids answering really basic math
questions. A large enough bunch of them could compute anything.
However with
parts getting tinier and tinier, quantum physics are making things tricky. In a
nutshell a transistor is just an electric switch. Electricity is moving
electrons from one place to another. So, a switch is a passage that can block
electrons from moving in one direction. Today a typical scale for transistors
is 14 nanometers. Which are about 8 times
less than HIV virus’ diameter, and 500 times smaller than red blood cells. As
transistors are shrinking to the size of only a few atom, electrons may just
transfer themselves to the other side of a blocked passage via a process called
Quantum tunneling. In a quantum realm, physics works quite differently from the
predictable ways we’re used to, and traditional computers just stop making
sense. We are approaching a real physical barrier for our technological
progress. To solve this problem, scientists are trying to use these unusual
quantum properties to their advantage by building quantum computers.
Qubits
In normal computers, bits are the
smallest unit of information. Quantum computers use qubits which can also be
set to one of two values. A qubit can be
any two level quantum systems, such as a spin and a magnetic field, or a single
photon. 0 and 1 are this system’s possible states, like the photons horizontal
or vertical polarization. In the quantum world, the qubit doesn’t have to be
just one of those; it can be any proportions of both states at once. This is
called superposition. But as soon as you test its value, by sending the photon
through a filter, it has to decide to be either vertically or horizontally
polarized. So, as long as it’s unobserved, the qubit is in a superposition, of
probabilities for 0 and 1, and you can predict which it’ll be. But the instant
you measure it, it collapse into one of the definite states. Superposition is a
game changer. Four classical bits can be one of two to the power of four
different configurations at a time. That’s 16 possible combinations, out of
which you can use just one. Four qubits in a superposition, however, Can be all
of those 16 combinations at once. This number grows exponentially with each
extra qubit. Twenty of them can already store a million values in parallel.
Entanglement
A really weird and unintuitive
property qubits can have is Entanglement. It is a close connection that makes
each of the qubits reacts to a change in the other’s state instantaneously, no
matter how far they are apart. This means when measuring just one entangled
qubit, you can directly deduce properties of its partners without having to
look.
A normal
logic gate gets a simple set of inputs and produces one definite output. A
quantum gate manipulates an input of superposition, rotates probabilities, and
produces another superposition at its output. So, a quantum computer sets up some
qubits, applies quantum gate to entangle them and manipulate probabilities,
then finally measures the outcome, collapsing superposition to an actual
sequence of 0’s and 1’s. What this means is that you get the entire lot of
calculations that are possible with your setup, all done at the same time.
Time travel is one of the widely discussed topics in the
world. When the term ‘time travel’ comes to the mind, people usually think of a
machine which can travel to the past or future within a moment. But this is
only possible in fantasies or fictions, not in real life. So, is it
theoretically or practically possible to travel into different times?
Basically we all travel with time. Time is running but in a
systematic way. Time doesn’t go backward. Time passes by but within a speed
limit. The speed limit is practically 1 hour per hour, 1 minute per minute or 1
second per second. We cannot change the limit. If we want to make a time
travel, we must change the speed limit of time. What if time travels 1 day per
hour?
Travelling To Future
The great scientist Albert Einstein had developed a theory
that is Theory of Relativity. This theory
describes the possibilities of time travel. It says, when an object travels
relative to other objects close to the speed of light, time will be slower for
it. The speed of light is approximately 300000 km per second. If any object can
reach almost 99.5% of the speed of light, it can travel to the future. To be
more specific, a man has left the earth and traveled to the space with the
speed of light. He has spent 1 year in the space with the same speed limit.
After coming back to earth after 1 year he’ll see the earth has already spent 5
years! His mates, friends have grown older than him. In a gist, he has
travelled to the future. So, traveling to the future is theoretically possible.
But to make it practically possible, we need to travel close to the speed of
light which we haven’t achieved yet.
So, as the man traveled to the future, can he come back to
the present or where he did belong? To make it possible, he needs to travel to
the past.
Travelling To The Past
There is a popular hindrance of traveling to the past and
that is- Grandfather Paradox. For example, a man from present time has
travelled to the past and met his young grandfather. He suddenly killed his
grandfather. What will happen? His grandfather won’t be able to give birth to
his (man) father. So, there will be no existence of his whole family. Likewise
there will be no existence of that man too. Then who went to the past to kill
the grandfather? This is an impossible fact and this is a hindrance to the fact
of traveling to past.
But there also two theories accepting the fact of time
travel- Novikovs self consistency theory and parallel universe theory.
Self-consistency theory: According
to this theory, if any man goes to the past he cannot get into any kind of
activities that will affect his present life. The nature will hinder him from
these activities. So, although he can travel to the past, he cannot change
anything or affect the past world. Mother Nature will play the role of
controlling everything. But this is just a theory.
Parallel
universe theory: According
to this theory, there are different universes for every chance. For, example, a
man just had an accident and lost his eye. There will be another universe where
he didn’t have any accident and enjoying his life with both eyes. Both the
possibilities will go parallel in different universes. This is like a tree and
its branches. As every tree has a lot of branches, every incident can have a
lot of results. And there is existence of parallel universes for every
possibility. So, according to this theory, a man cannot time travel to the same
universe he is living. It justifies the fact of time travel. But this is also
just a theory.
So far we have learnt that time travel is theoretically
possible with many limitations. There are physical and technical limitations. Our
technology is not that much developed to travel at a speed of light and travel
in different times. Even if we invent any technology of that speed, we don’t
know whether we human body can sustain it. Scientists are working with
wormholes (technology for time travel). So, as science is developing our dream
of time travel might come true one day.
Nature provides us natural resources to generate electricity
like natural gas, coal, ocean tides, mountain waves and sunlight. Some of this
resources are finite including fossil fuels like coals, natural gas etc. But
others are unlimited like solar or wind power. There are some significant processes
to turn the resources into usable electricity. Everyday researchers work to
find innovative ways to use our limited resources.
Thermal power: Thermal
power is widely used in the modern world to generate electricity. Fuels like
coal, natural gas, biomass and uranium are used to heat water until it produces
steam which runs turbines and generate electricity. Steam spins turbine blades
and turbines are connected to a shaft which spins magnet with a coal inside the
generator. It’s a generator which turns mechanical energy into electric energy.
Steam is an efficient method of producing electricity because the water can be
recycled and reused as it changes back into pure water.
Solar system:
Solar system uses sunlight to produce electricity. Photon rays hit solar panel
cells with energy and this energy dislocates electrons from solar cells. The
electrons travel around and run through a specific way to fulfill a circuit.
This is the simple way that solar panels follow to produce electricity.
Although it produces a small amount of electricity but it doesn’t require any
raw materials and also it is unlimited.
Wind turbines: Wind
turbines work as the opposite of a cooling fan. It uses wind power to produce
electricity. Wind turbines usually have three blades which are connected with a
shaft. Wind power rotates the blades and the blades spin the shaft. The shaft
is connected to a generator and it produces electricity.
Ocean tides:
Producing electricity using water waves or tides is quite similar to the wind
turbine system. The kinetic energy of the water waves or sea tides makes the
turbine blades rotate and produce electricity. Waterfalls are widely used to
produce water in this process.
Working method of Generators:
Michael Faraday
invented the electromagnetic induction of generators. Generators produce electricity using
electromagnets. They transform kinetic energy into electric energy. Generator
has a series of insulated coils of wire. There is an electromagnetic shaft
surrounded by cylinder of wires. As the electromagnetic shaft rotates, it
induces a small electric current in each section of the wire coil. The wire
coil rotates in a magnetic field. The rotation creates a voltage difference
between the two ends of the wire coil. This makes the electric charges flow.
Flowing of the electric charge generates electricity. Every small fractions of
electricity from wire coils combine a large current. And then we are able to
use the current. Almost every electricity resources use generator to produce
electricity.
Distribution
of electricity: Transporting
electricity from the power plant to home is an entirely different process.
Current technology cannot store large amount of electricity. So, significant
challenges come while transferring electricity across long distances. That’s why
a complex mix of management and infrustructers needed to transfer electricity
to consumers through the electricity grid, often known as 'the grid'. The grid
lines carry electrical energy at high voltage within their area to local
utilities. There are very limited links between the grids. So, electricity
cannot travel much far. For electricity to move far away the voltage must be
increased by a device called transformer.
Then the electricity can travel long distances through high voltage
transmission line. These high voltage lines are generally strong between giant
metal towers. There are sub stations alongside the roads. There job is stepping
down electric voltages from level as high as 765000 volts close to 110 volts to use in the local utilities. The electricity from the power
line on the street passes through another transformer which steps down the voltage
once more and then it travels along the line into the house. From there the
electricity enters the main switch board. Then it is distributed into the
sockets. Thus we get electricity turning the switches.
Invention of airplanes is one of the greatest evolutions in
the modern communication system. But few centuries ago, this was completely
impossible to think. Credits go to the Wright brothers who invented power
flight almost one century ago. All their hard works, experiments, researches
and dedications become successful and accelerated our world.
How does it
fly?
We see jet planes fly higher than usual airplanes. They even
exhaust a lot of smoke on the air because jet engines are long metal tubes
where continuous rush of fuel is burning. Jet engines are also far noisier than
usual airplane engines. Two most important parts of a plane that help it to fly
are Engine and Wings. They both work together to lift a plane up and move
forward. But they have differences between them. A plane engine is developed to
move the plane forward at high speed. Moving of the plane makes the air flow
over the wings. The design of the wings forces the air to go downward and
pushes the plane upward. The upward momentum created by a downward force is
called lift. The lift force is greater than planes weight. It makes the plane
detach from the ground and fly up. The process can be explained by Newton’s
Third law of Motion.
How does
wing work?
Wings are the main part to make a plane fly. It has two
surfaces: upper and lower. The upper surface is usually curved and the lower
surface is flatter. This design creates a cross sectional shape called airfoil.
As air goes over the upper curved surface, it travels further than the air
passes below it. So, it goes faster. According to Bernoulli’s law, Fast moving
air has lower pressure than slow moving air. So the pressure created in the
upper surface is lower than the pressure of lower surface. As there is low pressure
upside the plane goes upward. This pressure difference makes the lift of a
plane.
How does
Helicopter fly?
Helicopter doesn’t actually run, they can stay on the air.
Helicopter rotors use the similar technique as the airfoils do. It creates a
huge downwash of air to balance the weight of helicopter. Helicopter rotors
also have curves. As the chopper engine starts the rotation of the rotor, the
rotor rotates at a constant speed and force the air downward. The downward
force of air hits the ground and gives the chopper upward lift. It follows the
third law of Newton.
How do
planes steer?
Steering something means changing the direction of a
vehicle. Changing the direction results in change of velocity and acceleration.
To move something, we need to apply force. So, when it comes to steer
something, we need to apply force to it. The force is called Centripetal force.
Centripetal force usually comes from the friction when a vehicle is in touch
with the ground. But how does plane steer without being in touch with the
ground? It actually leans into a curve. The plane usually leans into an angle
and changes the direction with a curve of banking. The banking of the plane
provides centripetal force.
Other parts
of a plane-
Fuel tank: As
planes fly burning fuels, it must have a fuel tank where fuels will burn and
produce energy to move the plane with great speed.
Landing gear:
Plane’s wheels are hidden inside the plane while flying to avoid dragging.
Planes land on these wheels. When plane prepares to land, the wheels come out.
Radio and Radar: These
systems are essential for a plane to navigate from the sky. Skies these days
are so busy with a lot of air traffic. So, Radio, Radar and Satellite is useful
to communicate between planes and with airports.
Pressurized cabins:
Planes should have pressurized cabins because as plane goes high, the air
pressure reduces. To maintain the pressure balance, pressurized cabins pump
heated air so that people can breathe easily.
Although planes fly following a simple scientific method but
the mechanism of it is far more complex. Scientists and inventors are
developing the aircraft system every moment. We are getting more and more
modernized aircrafts. The communication system over the sky is getting easier
and fast. Even few decades ago the situation was quite different but today we
see thousands of flights all over the world is taking place in just a moment.
This is a blessing of science.
Fossils are the
ultimate formation of those creatures which lived long ago on the earth. They
are buried beneath the earth layers for million years. The creatures transform
into fossils and can be used as fuels. Fuel is a source of non-renewable
natural energy. People use fossil fuels in driving cars, producing electricity,
cooking etc. So, fossil fuels are the inalienable energy sources in human life.
Fossil fuels store energy and emit them when they are burnt. They get energy
from sunlight. Plants produce their own food from sunlight. The energy passes
to the animals. These energies remain in the animals and plants. After they die,
they transform into fossil fuels.
Formation of fossil
fuels
Fossil fuels are formed under the layers of rocks. Most of
the rocks are sedimentary rocks. They create layers year after year. The layers
keep building up and their pressure beneath layers increases. The temperature
also increases
relatively. When plants or animals remain under these layers for million years
they transform into coals, oil and natural gas. As sedimentary layers build
they put pressure on the older layers. The more layers are build the more
pressure increases there. And energy in the fossil fuels also increases
relatively. Sediment layers are usually formed under sea, lakes or valley. So,
as water flows over the sedimentary layers, the dissolved minerals in the water
sticks to the layers and form a kind of cement. This type of cement helps to
transform the sedimentary layers into rocks.
How do coals form?
Coals usually form from dead plants which are buried beneath
the sedimentary rocks. Plants under sea or swamps transform into peat and after
the peat is buried under more layers it becomes coal. Coals are also sedimentary
rocks. They receive energy from pressure and emit them when burnt.
How do oil form?
Oils are generally a transformation of microscopic animals
that lived in ancient times. They were buried under sedimentary rocks million
years ago. Getting pressured by layers they transform into oils. Getting more
pressure they become natural gas. Oils are reserved in the tiny pores of the
rocks. As the pressure builds the layers squeezes the oils drops into pores.
But this is not at all easy to drill out oil from underground. Engineers
research for right places to drill out oil. They set up machines but they can
only put out a quarter of oils from the remaining of the reservoir.
How does natural gas
form?
We have already learnt about how oils are formed. The
formation process of natural gas is same but it requires a lot more pressure.
When oils underground get more pressure from sedimentary rocks they transform
into natural gas.
Uses of Fossil Fuels
in everyday life
We get petroleum and refine it because before it is refined
petroleum is something like crude oil. After refining it we get various type of
oil. One such type is gasoline. When gasoline is burnt it releases a lot of
energy and the energy can be used to propel vehicles. Diesel is another fossil
fuel that is used to run vehicles. We burn coals, oil and natural gas to get
electricity. Also various products of our everyday life come from fossil fuels
such as ball-point pen, printer cartridges, lipstick, polyester clothing etc.
People use natural gas and oil to cook, heat up the house. So, fossil fuels
have impact on our everyday life. The uses of fossil fuels are so wide that there is a concern of running
out of them.
Can we run out of
fossil fuels?
If we keep using fossil fuels like today we might lose all
the remaining fossil fuels. Because fossil fuels takes million years to form.
Moreover they are non renewable energy sources. We should reduce the wide use
of fossil fuels in order to use them longer time.
Impact on environment
Burning of fossil fuel has impact on the environment. It
releases green house gas that is the cause of global warming. Removing fossil
fuels from the environment pollutes the environment.
In order to see something, the object either needs to emit
light directly like the sun or a bulb or else light has to be reflected from an
object into our eyes. An object will be invisible when it is not perceivable by
the eye. For this to be possible either light ray should not enter the eye or
even if they enter we should not be able to sense it. There are some scientific
possibilities to become invisible. Although there are limitations in every
process but there are really some promising and useful ways in the term of
invisibility. Few possibilities are discussed below:
1. Move at great speed:
There are few theories that say that
an object can turn invisible when it travels at a speed greater than that of
light because light cannot catch up with it. But Einstein’s special theory of
relativity says that we need infinite amount of energy to get an object to
reach the speed of light. This is not practically possible. What if we can make
an object move at a very fast velocity but less than that of light so that we
can’t see it? If we see the example of a bullet, when a bullet is fired off the
gun, it becomes invisible because it is travelling at a great speed. Now, we
understand that a bullet can become invisible. So, can a human become invisible
in the same process?
To become invisible one must run so fast which will be
practically impossible. There is no such technology invented so far that can
move a human being at a great speed to become invisible. The speed should be
approximately 12 times faster than a F1 car and the angling of the eye should
be limited.
2. Bending of light:
Here we try to take light pass it
around an object as if it weren’t there. Just like a light from light source
suddenly bends and passes the object and doesn’t fall on the object. In this
process the object would be invisible. This is very simple in theoretical way
but very complex in the practical way. To make this theory work, we need to
make a setup. This setup should have reflectors which would reflect the
background of the object into eyes. So, the object inside the setup would go
invisible and only the background will be visible. But there is a limitation,
the object or human inside the setup cannot see anything outside the setup. So,
this process can be used only to hide something.3. The invisible ink:
A red colored object appears red because it absorbs all colors
and reflect only red. So does every color. Only rays having a wavelength of
380-740 nanometers can be perceived by the human eye. What do infrared colored
object looks like? Would they be invisible? If we paint a human with red ink,
he will look red. But what if we paint him with an infrared paint? Would he be
really invisible? No. As the infrared ink absorbs all colors except infrared it
turns out that it absorbs all colors in the visible range. So, the paint will
be perceived as black but not visible. Invisibility is not about absorbing the
light but we should be able to see what is behind the object.
4. Using cameras and displays:
In this process a camera
captures the background of an object and projects it onto a screen creating an
invisible region. If you look at the screen from a different direction you'll
understand that this is only a projection. So, to make it look more real we
have to track the eye of the observer and change the display screen
accordingly. But if there are two people, there system would be failed.
5. Metamaterials:
Scientists have developed an invisible
cloak which can bend electromagnetic radiation around an object and it is known
as Metamaterials. Metamaterials can bend light around an object, giving the
appearance that it isn't there at all. But this technique only worked with
microwave light so far. Scientists are trying to develop the concept to make it
work with visible lights too. The invisible cloak is generally made out of
silk. Materials are developed to bend light so that eyes can see what lies
behind the object and make the object disappear. 
Satellite is an space based object that orbits the planet.
There are two types of satellites: Natural and Artificial. Moon is a natural
satellite of earth that is continiously orbitting the earth. And arificial
satellites also orbits earth. They are developed in the purpose of Communicating,
Imging, Scientific surveying and Navigation. Satellites have made global
communication system more easier, quicker and more realistic. It has connected
the whole world with its bound. There are almost 2000 artificial satellites
orbitting the world. These carry analog and digital signals such as voice,
pictures, videos and data from one part of the world to another. There are two
types of artificial satellites: Polar and Geosynchronous.
Polar: polar satellites doesn't rotate with the earth as it
just float on the space. The earth rotates and the whole earth becomes subject
to its perscrutation.
Geosynchronous: These satellites are associated with a
particular location and they rotate
following the rotation of earth's rotation. Only a particular location becomes
a subject to its scrutiny.
What do Satellites do for us?
Satellites are used for many purposes. They Are mostly used
for communication, Photography, Imaging, Scientific surveys or researches and
Navigation.
Communication: Communication
satellites use radio waves to communicate with the ground stations. It
catches signals from the ground signals from the ground station and amplifying
or modifying themtransmits them to another ground station. Television, Radio,
Internet Cellular phones communicate via satellites. It is also ueful in the
areas where typical wired or wireless systems doesn't work.
Photography, Imaging and Scientific Surveys: People all over
the world use google map or Google Earth systems which work with the help of
satellites. Satellites capture high quality pictures of the ground. It can
monitor live activities such as live traffics and pedestrians on earth. They
are also used for many purposes such as measuring sea levels, measuring
plunktons and nutritional activity scanning the color of the ocean, Weather
forecasting, Mapping and monitoring changes in land etc.
Navigation: People all over the world us GPS system to track
the maps and location and to get street directions. People also use it as sky
compass to get direction. These are possible by the help of Satellites.
What is inside a satellite?
A satellite is a very complex and expensive machine. But we
will only discuss about the simple basics. There are a some essential parts of
a satellite. Such as,
• It has
large and small parablic dish antennas for sending and receiving signals.
• It has
upper and lower solar batteries of four solar panels in each. The solar panels
are the sorce of power for a satellite.
• It has
supports that hel to fold out solar panels.
• It has
main satellite rocket motor.
• It has
controll engines that keep the satellite in its precision, position, spin and
orbit.
How does Satellite works?
As satellites receive signals from ground stations so there
should be some ground stations to communicate with satellites. Earth or ground
stations send information and data via radio waves in the form of high
frequency signals to satellites. They receive and retransmit them back to
earth. The retransmitted signals are received by other earth stations in the
range of the satellite. The transmission system from the earth is known as
uplink and the retransmission from the satellite is called downlink.
Who Invented satellite?
The idea of satellite technology was first revealed by a science
fiction author Arthur C. Clarke. He proposed of geosynchronous satellite which
can cover a third of the planet each. Although he didn't patent it, he is
generally credited with its invention.
Depending on where it originates from, the
sun, the moon, lightning, certain types of glowing insects, worms and fishes
etc. are all example of natural sources of light. While, a candle flame,
various types of torches, lamps and light fixtures are amongst the artificial
light sources.
·
Visible
light
Our sun emits light. Really strong intense
light or radiation called electromagnetic radiation or EMR. The radiation is
called electromagnetic because it contains both electric and magnetic
properties. Electromagnetic radiation is a large family consisting seven
members known as The Electromagnetic Spectrum. Our particular family member
which lies in the middle of the spectrums, falls on the earth and which our
eyes detect is called visible light or the visible spectrum. Its fraction is so
small that if we consider the entire EM spectrum to be around 2500 miles, the
visible fraction would be just one inch! It is within this inch that we live in
our world of natural and extra ordinarily high definition color. We enjoy this
privilege of color due to the presence of certain specialized cells in our eyes
called Rods and Cons.
·
Invisible
light
Now
the other type of electromagnetic radiations is also called light but not
visible light. So, automatically they are considered by us to be invisible. So,
now we know the light which we have naturally been introduced to since birth
and that we see throughout our life is actually radiation and radiation of a
good type that an important source of energy for life on earth as we have seen
earlier. Now, just as members of a family differ from one another and have
their own unique identity, so also these fractions of radiation, although part
of the same family of light, are slightly different from one another. These
different are due to three factors that are independent and give each member,
its individuality. These factors are Wavelength, Frequency and Energy. The
shorter the wavelength is the higher the frequencies and energies are. And the
longer the wavelength is the lower the frequency and energy is.
Types of light:
1.
Radio wave: It has the
longest wavelength with lowest frequency and energy. They are used for
broadcasting TV and radio signals because they can cover a greater distance
through the atmosphere due to their large wavelength. They are usually emitted
and received by antennas.
2.
Microwaves: It has
shorter wavelength than radio waves and higher frequencies and energy. These
waves are used in the appliances like the microwave oven. They are also used in
channels of telecommunication like mobile networks, Bluetooth and wireless LAN
protocols.
3.
Infrared: This
region of spectrum is more known for the aspect of heat associated with it as
they have higher energy as compared to radio waves and microwaves. They are
used by appliances like grills and electric stoves for heating and cooking
food. IR is also used as a part of heat therapy to relieve aches and pains.
4.
Visible: Visible
light has the wavelength in the range of 380-780 nanometers. Visible ray are
simply of those wavelengths which our eyes can detect. It has colors and that
is what we see.
5.
UV or Ultra-Violate: The uses
of ultra violate radiations are also widespread in various aspects of life.
They are used as sterilizing agents by the medical industry and by water
purifiers to get rid of harmful bacteria.
It is used by dentist to harden teeth filling and by banks to detect
fake currency notes.
6.
X-Ray: As we are
aware, x-ray is also used to a great extent by the medical industry to examine
the state of bones or foreign object in the body. It is also used by airport
security to scan luggage for partially dangerous objects.
7.
Gamma: Gamma rays
are a type of radiation with the lowest wavelength and the highest energy. They
are the exact opposite of radio waves. They are emitted by radioactive
materials, given off during nuclear explosions and during certain types of
thunder storm. But despite of the fearful reputation they are used to kill
cancer cells for medical and security scanning and also by space observatories
for astronomical observations.
|
Light
|
Wavelength
|
|
Radio wave
|
5m- 1m
|
|
Microwave
|
1 m-1 mm
|
|
Infrared
|
1 mm-780nm
|
|
Visible
|
780nm-380nm
|
|
Ultra Violate
|
380nm-10nm
|
|
X-Ray
|
10nm-0.01 nm
|
|
Gamma Ray
|
0.01 nm-0.00005nm
|
4G stands for fourth-generation
wireless cellular service that is almost 10 times faster than 3G network. The
1G or 1st generation was the old analog cellular system. That was
obviously super slow. 2G or 2nd generation moves to digital but they
were still very much slow, somewhere around 10-200 kbps. The first iPhone was
2G. 3G is a much faster digital and it starts around 384 kbps+. 4G systems like
LTE and WiMAX claim to initially start around 5 mbps which is a lot higher than
all the previous systems. But 4G isn’t just faster than 3G, the 4G network also
tend to have a lot more capacity than 3G network. On 4G, there should be a lot
more data plans. But sometimes people argue that there is no such difference in
3G and 4G as if they both serve the same service. Because, 3G networks
sometimes are really faster than the beginning of 4G. For example, HSPA+, is 3G
basically but it is really fast 3G somewhere around 7 mbps.
4G was first experimented in the
U.S. beginning in 2009. Smart phones or recent digital devices are functioned
to stream videos and music and so internet speed became so important. Whenever
someone is moving with high mobility, it will require huge data rate. So, in
order to make the requirement of high speed mobility like trains, bullet
trains, super cars, we need 4G. 4G is developed quite highly that it can be
compared with broadband connections where previous cellular speeds were much
slower than high speed broadband connections to computer.
Requirements: To have access to 4g network, a 4G capable device is
required. Devices with 4G capabilities are available widely these days. 4G
compatible devices usually have larger screens, extremely fast RAM, great
processors and powerful batteries.
There are several types of 4G such
as 4G LTE, WiMAX. But LTE is much faster as it can reach up to 100 mbps while
WiMAX can reach up to 70 mbps.
Why 4g?
4G makes the data transmitting or
accepting rate real faster. When a device send a picture to another via wireless
system, it disassembly converts into separated codes and when the other device
receives the codes it reassembles and converts them into a picture. So, the
converting and assembling rate depends upon the networking system. 4G is
developed for doing these things real faster. It saves time and makes things
quicker. Communications between 4G networks becomes smoother and faster.
Why 4G is faster?
The modulation and coding scheme of
4G network contains a lot more symbols or bits. It also can have a bandwidth of
20 MHz in a single carrier while a 3G network can have only 5MHz.
So, 4G is an evolution of mobile networks. As
we approach to the future, we will be getting faster networks with the
development of science and technology.
LiFi or light fidelity is a high speed and
fully networked wireless communication technology similar to WiFi. It uses
visible light rays to transfer data and is 100
times faster than WiFi. This is because the light has the capacity to
transfer vastly more amount of data in a less time compared to radio waves.
Method: The
ceiling LEDs encode data from internet and decode it into light. The LED light
is switched ON and OFF at a very high rate, too quick to be noticed by human
eye. This process works like a binary code. This light is then received by a
photon detector which converts the variation in the intensity of light into
electrical charges. These electrical charges are then converted to binary data
and send to computer or mobile devices.
Invention: The LiFi technology was founded by a
University Professor, Herald Haas. Haas
envisioned light bulbs that could act as wireless routers. Subsequently, in
2012 after four years of research, Haas set up a company called pureLiFi with the aim to be the world leader in
visible light communications technology.
How does LiFi work?
LiFi technology is basically based on the
idea of Solar Panel system. LiFi and WiFi are quite similar as both transmit
data electromagnetically. However, WiFi uses radio waves while LiFi runs on
visible light. LiFi use a photon detector to receive light signals and signal
processing elements to convert the data into ‘stream-able’ content. An LED
light bulb is a semi-conductor light source meaning that the constant current
of electricity supplied to an LED light bulb can be modulated at very high
speed without being visible to human eye. For example, data is fled into an LED
light bulb with signal processing technology. It often sends data which is
embedded in its beam at very high speeds to the photon detector. The tiny
changes in the rapid dimming of LED bulbs are then converted by the receiver
into electrical signal. The signal then converted back into a binary data
stream that we could recognize as web, video and audio applications that run on
internet enabled devices. The converted binary codes look like this,
Binary=
‘101101001101001’
LiFi features- benefits to the capacity,
energy efficiency, safety and security of a wireless system with a number of
key benefits over WiFi. But it’s worth mention that LiFi is not aiming to be
direct replacement for WiFi and cellular networks, it’s a complementary
technology that will work well in certain situations.
Professor Herald Haas, the person who coined
the term LiFi, expect LiFi to unlock the third industrial revolution. The
technology seems promising and many major key players are considering it.
Microsoft is implementing the lucibel’s LiFi solution at its innovation center
in France. There have been news reports that Apple is experimenting with LiFi
wireless data for future iPhones and iPads.
Limitations of LiFi: LiFi is undoubtedly a promising and revolutionary
invention but it also has some limitations.
·
LiFi might not be able to work smoothly in
direct sunlight or harsh lighting. They might create problems in detecting the
modulating light waves
·
LiFi may cover only a single room as light
cannot pass the walls. If anyone is connect to the LiFi and want to move to another
room, he better have another light bulb set up there.
·
Light bulb has to be on all the time, even
during night.
LiFi technology does offer numerous benefits,
but there are still important challenges that must be overcome before it
becomes an essential part of everyday wireless communications.
Since the beginning of the industrial
revolution, the demand for energy has increased dramatically year after year.
As the world is developing and population is increasing, the rising rate for
the demand of energy is very logical. Nuclear power system is one of the widely
used energy source in the world.
History:
It all started in the 1940s. After the shocking disasters by
the use of atomic bomb, nuclear energy was promised to be used peacefully by
the new technology. So, the world can be back on its feet. Everyone’s
imagination was running wild. Would electricity become free? Could nuclear
power help settle the Antarctic? Would there be nuclear powered cars, airplanes
or houses? It seemed this was just a few years of hard work away. One thing was
certain that the future would be atomic. Just a few years later, there was a
sort of atomic age hangover. As it turned out, nuclear power was a very
complicated and very expensive. Turning physics into engineering was easy on
paper but hard in real life. Also private companies thought that nuclear power
was much too risky for investment. Most of them would rather stick to Gas, Coal
and Oil. But there were many people who didn’t just want to abandon the promise
of the atomic age and exciting new technology. The prospect of cheap
electricity, the prospect of being independent of Oil and Gas and in some
cases, a secret desire to possess atomic weapons provided a strong motivation
to keep going. Nuclear power started to become popular in the early 1970s when
oil price in the Middle East increased. Now, commercial interest and investment
picked up at a dazzling pace. More than half of all the nuclear reactors in the
world ware build in between 1970 and 1985.
Buildings:
Nuclear power plants are thermal power stations which
generate electrical energy from it. They consist of numerous buildings and
facilities. The most important of which are here:
- · In Turbine buildings there are several turbines as well as generator necessary for electrical power generation.
- · There is a containment building where the nuclear reactor is housed.
- · Inside the Cooling tower, nuclear reactions take place where water is heated up. In this building, hot water is cooled.
Process:
In order to easily understand the underlying principles,
the following is a description of the most important components of a nuclear
power plant that uses a pressurized water reactor (PWR). In the reactor
pressure vessel, the nuclear reaction and the associated release of thermal
energy takes place. Inside a pressurized water reactor, the fuel assemblies can
be found. About 150 such assemblies are installed in it. A single fuel assembly
is composed of many fuel rods. The actual nuclear fuel is found inside of each
fuel rod. Small nuclear fuel pallets are composed of enriched Uranium or Plutonium
that make nuclear fission chain reaction possible. In the fission chain
reaction, thermal energy is released.
Water is
needed in order to absorb the thermal energy and keep the chain reaction going.
Inside the vessel the water is heated to over 570 degrees Fahrenheit. The water
does not boil however since the pressurizer maintains the water pressure
constant. The heated water is eventually pumped to a heat exchanger also called
steam generator. Any water inside the heat exchanger begins to boil. The
resulting steam is eventually fled through a set of pipes to the turbine
building. The steam first arrive high pressure turbine and then is typically
fled to two low pressure turbines. All of the turbines are connected by a spinning
shaft through the electrical generator which in turn produces AC electricity
from the shaft’s rotational energy. The steam is converted into liquid
form in a condenser and then returned back to the steam generator.
The water
needed for this often comes from a near river or is cooled in a cooling tower.
The water circulation systems are always kept separate from one another.
Wifi stands for wireless fidelity,
a popular technology used to connect to the internet without hardware cables.
It also allows devices like laptop, Computer, mobile phones to exchange
information. It can also be taken as a synonym of WLAN.
Wifi network is built
with the help of several hardware components like wireless access points or
routers and user devices. Wifi router is the main hub of wifi network. It is
usually connected to a high speed modem. The modem is connected to an Internet
Service Provider (ISP) from where it gets hardware signals. The modem sends
hardware signals to wifi router and the router converts them into radio waves.
The radio waves can be accessed through any wifi supported devices.
Wifi signals are transmitted into
certain frequencies, either 2.4 Gigahertz or 5.0 Gigahertz. But other usual
devices like walky-talkies, radios, car radios etc use frequencies in kilohertz
and megahertz range.
Wifi is a network carrying
instructions which tell the connected devices what to do in each pixel on the
screen. The instructions are converted into codes which only need two different
modes- On and OFF. For example, a code might be this-
-OFF-OFF-OFF-OFF-OFF-OFF=A
OR
-ON-OFF-OFF-OFF-OFF-OFF=B
OR
-ON-ON-ON-OFF-OFF-OFF=C
To transmit a
picture, we’ll need huge amount of ON-OFF signals and for video, even more.
Luckily for us, electro-magnetic radiations travel in the speed of light. So,
even something really so complex can be transmitted super quickly.
The area where
wifi access is available is called hotspot. Any digital device within the
hotspot range can connect to the wifi network. The range is not possible to be
defined accurately but a typical wifi network can cover a whole family
apartment. Business networks can cover
a whole office building. Even there are examples of setting wifi covering
several square miles in some cities. The network speed varies from device to
device and depending on distance from router. Wireless range is possible to be
effected by surroundings such as natural elements and obstacles. Physical
obstacles like walls or concretes, water and even human beings can slow down
wifi. Sometimes microwave ovens can create disturbance in the network because
it also uses the frequency range of 2.4GHz.
There are
several types of wifi network depending on the speed limits. The costs for the
network also depend on the speed limit of wifi.
