Science Reporter Nov'17 Magazine For UPSC 2018 - Science & Tech Current Affairs -

Index
 Starvation (Fasting) Therapy
 2. Safety on wheels: A Crash Test!
 Advanced Automotive Materials
 Wireless Transmission of Electricity
 Solar-based satellite Power
 Laser Energy Transmission (LET)
 What is DNA fingerprinting Technique?
 Starvation (Fasting) Therapy
In fasting period the first energy source that is depleted is glycogen.
Liver based glycogen is depleted in the first 18-24 hours of fasting.
After that, the energy is derived from protein, amino acid, muscle glycogen and fat
stored in the form of triglycerides in adipose tissue.
In the first phase of fasting, i.e. 6-24 hours after the beginning of fasting, the total
glucose use is 150 to 250 grams per day. The brain consumes about 125-
150 grams while the remaining is consumed by muscle cells, bone marrow
cells, peripheral nerve and renal medulla.
As fasting progresses, fatty acid metabolism results in the increased
production of ketone bodies, which replaces glucose as the primary
energy substrate for brain during prolonged starvation. Today, ketogenic
diets are referred by nutritionists to lose weight.
Ketogenic diets have also been found to have health benefits like use as a
treatment for cognitive impairments, including Alzheimer’s Dr. Ravi Agrahari’s Classes
(Scientist in IIT Delhi, Author of Mc Graw Hill) symptoms, prevention and even killing of cancer cells, and also
reduction in cardiovascular disease risk factors.
 2. Safety on wheels: A Crash Test!
According to World Organization statistics (WOS), there were around
1.25 million road traffic deaths globally in 2015, which was nearly equal
to the population of Mauritius.
There are two types of safety features in vehicles:
1. Passive Safety Features: Airbags are an example of ‘Passive Safety
Features’, which prevent or minimize injury to the passengers in a crash.
2. Active Safety Features: Safety features in a vehicle that help prevent a
crash by providing the driver with better ways of controlling the
vehicle and avoiding hazards are called ‘Active Safety features’. Anti-Lock
Breaking system, Electronic stability control, Automatic Braking are
some examples of ‘Active Safety Features’.
Anti-Lock Braking System (ABS)
Skidding is the phenomenon of locking up the wheels of a vehicle when a
sudden or extreme braking force is
applied. When the front wheel(s) of a
vehicle are locked its ability to change
direction is reduced.
Autonomous Emergency Braking (AEB)
A number of crashes are caused due to late braking and/or braking with
insufficient force. A driver may brake too late for several reasons: he is
distracted or inattentive; visibility is lower, for instance when driving in
heavy fog, rain or snow; or in unpredictable situations, when the driver
ahead brakes unexpectedly.
Most AEB systems use radar, stereo camera
Dr. Ravi Agrahari’s Classes
(Scientist in IIT Delhi, Author of Mc Graw Hill)
and/or LiDAR (Light Detection & Ranging) based technology to
identify potential collision objects in front of the car.
If a potential collision is detected, generally AEB systems first try to
alert the driver that an emergency action is needed. If still no action is
taken and a collision is imminent, the system will then apply the
brakes.
Lane Departure Warning System
Lane Departure Warning system warms the
driver when the car is getting close to a lane
marking. The type of warning can be
different depending on the system. While
some systems give an audible signal,
others prod
Dr. Ravi Agrahari’s Classes
(Scientist in IIT Delhi, Author of Mc Graw Hill)
technique known as ‘handbrake hill start’, in which the driver engages the
handbrake of the car momentarily, while pulling away on an inclined
surface.
Electronic stability Programme (ESP)
It monitors the wheel speed sensors,
steering wheel angle, lateral acceleration,
yaw rate, etc. to detect if the driver is
losing control. ESP employs in tandem,
ABS, Electronic Brake Force Distribution
(EBD), Traction Control System (TCS) and Active Yaw Control (AYC) to
stabilize the vehicle and keep it on the road
Pedestrian Airbag
Volvo is the first company to introduce ‘pedestrian airbag’, a technology
first used in their Volvo V40. The
‘Pedestrian Airbag’ is probably the
only one-of-its-kind features that
offers protection to the
pedestrian, and also minimizes
impact forces and resultant
injuries.
The airbag is designed to protect pedestrians from accidental injuries at
city speeds, from around 12 mph to 31 mph.
Cruise Control
Often over long distances driver
fatigue leads to vehicle crashes.
Cruise Control is a system that
automatically controls the
speed of a vehicle on long
stretches of highways with
constant flow of traffic. The
purpose of Cruise Control is to accurately maintain a speed set by the driver
Dr. Ravi Agrahari’s Classes
(Scientist in IIT Delhi, Author of Mc Graw Hill)
without any outside intervention by controlling the throttle-accelerator
pedal linkage.
 Dynamic Cruise Control: It is not exactly a collision avoidance system,
but only serves to maintain a desired vehicle speed as set by the
driver.
 Adaptive Cruise Control: With the number of cars on roads increasing
exponentially, the functionality of normal (Dynamic) Cruise control is
becoming obsolete. It lets the car hold a speed but allows adjustment
to changing traffic with the help of automatic braking and
acceleration. A radar sensor continuously monitors the distance to
the vehicles in the front and automatically adjusts speed to
maintain a proper safe distance, thus preventing rear-end
collisions.
 Advanced Automotive Materials
In earlier times, metals like steel and aluminium were the only choice of
materials available to build cars.
High quality plastics are not only light weight but easy to mould, and
strong as well.
Similarly, magnesium is one of the lightest metallic structural materials
available and is almost 1.5 times less dense than aluminium. Wheels
made from magnesium are significantly lighter than aluminium alloy
wheels, and have almost the same strength.
Titanium has the highest strength of any material for its density. This
helps reduce the car’s weight and provides tougher parts.
 Wireless Transmission of Electricity
Wireless Power Transfer (WPT) has become very important now a day as
portable technology has become a part of everyday life.
The founder of AC electricity, Nikola Tesla, was the first to conduct
experiments dealing with wireless charging and accomplished a major
Dr. Ravi Agrahari’s Classes
(Scientist in IIT Delhi, Author of Mc Graw Hill)
breakthrough by transmitting 10⁸ V of high-frequency electric power
over a distance of 25 mile to light 200 bulbs and run an electric motor.
In 1901, Tesla constructed the Wardenclyffe Tower to transfer
electrical energy between America and Europe through the
Ionosphere. The Tesla Tower was about 185 feet high, with a well about
100 feet deep, for use in experimenting with the transmission if electrical
energy for power and lighting purposes by wireless.
The equipment cost was nearly $200,000. However, due to technology
limitations (e.g., low system efficiency due to large-scale electric field), the
idea has not been further developed and commercialized.
Latter, during the 1920s and 1930s
magnetrons were invited to convert
electricity into microwaves, which
enable wireless power transfer over
long distan
Dr. Ravi Agrahari’s Classes
(Scientist in IIT Delhi, Author of Mc Graw Hill)
Wireless Charging Technologies
The development of wireless charging technologies is advancing towards
two major directions. ’Rediative wireless charging’ using radio
frequency or microwaves is used for long distance transmission of
power. Due to the safety issues raised by RF exposed radiative wireless
charging usually operates in a low power region.
‘Non-radiative wireless charging’ (or coupling-based wireless charging)
is based on the coupling of the magnetic field between two coils within
the distance of the coils dimension for energy.
It involves inductive coupling, magnetic resonance coupling, and
capacitive coupling. Due to safety implementation, non-radiative
wireless charging has been widely used in our daily appliances.
Inductive charging: Most of today’s wireless chargers use ‘inductive
charging’ with transmit and receiver coils in close proximity (only few
centimetres). The action of an electrical transformer is the simplest instance
of wireless energy transfer via induction. The transfer of energy takes place
by electromagnetic coupling through a process known as mutual induction.
In ‘resonance charging’ the transfer efficiency and power transferred
are a little lower compared to induction charging, but the transfer
distance can be in metres.
‘Radiate wireless power transfer’ is used to transfer large amounts of
power over long distances through space by means of microwaves. A
Microwaves Power Transfer (MPT) system converts Direct Current
(DC) power to microwaves, transmits the microwave radiation to a
receiver which then converts the microwave radiation back to DC
power.
 Solar-based satellite Power
Solar Power Satellite (SPS) tap into the solar energy using a large-scale
photovoltaic array in space and transmit it to the ground using
microwave or laser beam. It has a great potential for large-scale clean
energy system to replace the fossil plants.
Dr. Ravi Agrahari’s Classes
(Scientist in IIT Delhi, Author of Mc Graw Hill)
The time average power per unit area in space is 5-10 times larger
than that on the ground, while the power loss for the wireless power
transmission/reception is expected to be less than 50%. Thus, SPS has a
competitive advantage over solar power plants on the ground.
 Laser Energy Transmission (LET)
In principle, laser energy transmission systems are very similar to energy
transmission via microwave technology: the power source (solar,
electricity) is converted into an emitter or an emitter array that generates
the directional electromagnetic radiation shining a laser beam, which is
subsequently absorbed in a receiver that transforms the energy back into
electricity. The advantage of a laser is that its monochromaticity allows
better control of the beam over long ranges.
Dr. Ravi Agrahari’s Classes
(Scientist in IIT Delhi, Author of Mc Graw Hill)
 What is DNA fingerprinting Technique?
In the year of 1984, Alec Jeffrey of Leicester University invented the
DNA Fingerprinting technique.
In India the pioneering uses of this technique has been credited to Dr. V.K
Kashyap and Dr. Lalji Singh of the CSIR-Center for Cellular and molecular
Biology, Hyderabad.
We can consider that, each individual has its unique DNA Fingerprinting,
half of its contributor is the mother and another half the father. This
unique DNA Fingerprinting is fixed since birth and can never be
changed over time. It is identical for every cell, tissue and organ of one
individual. The ideal way to distinguish one individual from the other
therefore is to compare the entire sequence of their genomic DNA.
Deoxyribonucleic acid (DNA) is the genetic blueprint of life that consists of
complex molecules called nucleotides, which are composed of one of four
nitrogen bases, a phosphate group and a sugar. These nucleotides are
bonded together in a particular fashion in one strand of DNA. The nitrogen
bases are Adenine [A], Guanine [G], Cytosine [C] and Thymine [T]. Two
strands resulting out of these sequences of nucleotides are twisted to
generate the double helix structure where a specific hydrogen bond
between the nucleotide bases forms (A=T and G=C). The organization of the
base pairs within a DNA forms a code that constitutes the specific order of
the nucleotide bases-this code is what is called the ‘gene’ and it is these
genes that are responsible for protein synthesis. Human DNA contains
approximately 40,000 genes present at different segments of the DNA
separated by certain sequences that do not code for proteins.
VNTRs and RFLP
There are several types of repeated segments used for DNA
fingerprinting.
Variable Number Tandem Repeats (VNTRs): Variable Number signifies
the diverse nature of the number of repeats whereas tandem repeat
describes the adjacent location of the repeated units. These VNTRs are
Dr. Ravi Agrahari’s Classes
(Scientist in IIT Delhi, Author of Mc Graw Hill)
also called minisatellites. VNTRs were earlier used for DNA
Fingerprinting along with Restriction Fragment Length Polymorphism
(RFLP) technique.
In this technique, the VNTRs are cut at specific positions by restriction
enzymes producing DNA fragments of different length. The varying
length of the DNA fragments are identified by electrophoresis along
with another technique called Southern Blotting and a DNA
Fingerprint is generated. Multiple VNTR markers can be targeted at a time
to increase the resolution of the result.