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BIOLOGY FOR ENGINEERS

MODULE 4
NATURE-BIOINSPIRED MATERIALS AND MECHANISMS (QUALITATIVE)

Echolocation (ultrasonography, sonars), Photosynthesis (photovoltaic cells, bionic leaf). Bird flying
(GPS and aircrafts), Lotus leaf effect (Super hydrophobic and self-cleaning surfaces), Plant burrs
(Velcro), Shark skin (Friction reducing swim suits), Kingfisher beak (Bullet train). Human Blood
substitutes - hemoglobin-based oxygen carriers (HBOCs) and Perflourocarbons (PFCs).

ECHOLOCATION:
In nature's sonar system, echolocation occurs when an animal emits a sound wave that bounces off
an object, returning an echo that provides information about the object's distance and size. Over a
thousand species echolocate, including most bats, all-toothed whales, and small mammals. Human
echolocation is the ability of humans to detect objects in their environment by sensing echoes from
those objects and by actively creating sounds: for example, by tapping their canes, lightly stomping
their feet, snapping their fingers, or making clicking noises with their mouths. People trained to
orient by echolocation can interpret the sound waves reflected by nearby objects, accurately
identifying their location and size.
Many blind individuals passively use natural environmental echoes to sense details about their
environment: however, others actively produce mouth clicks and can gauge information about their
environment using the echoes from those clicks. Both passive and active echolocation help blind
individuals sense their environments.
Those who can see their environments often do not readily perceive echoes from nearby objects,
due to an echo suppression phenomenon brought on by. the precedence effect. However, with
training, sighted individuals with normal hearing can learn to avoid obstacles using only sound,
showing that echolocation is a general human ability.
A comparison of biological echolocation and technological echolocation is given below:
Biological Echolocation
• Found in various animals such as bats, dolphins, and some species of whales.
• Relies on the emission of sound waves, usually in the form of clicks or vocalizations.
• Animals emit sound waves and listen for the echoes produced when the sound waves
bounce off objects in their environment.
• By analyzing the echoes, animals can determine the location, distance, and even theshape
of objects around them.
• This ability is mainly used for navigation, hunting, and communication in the animal
kingdom.
• Biological echolocation is a natural adaptation that has evolved over millions of years.
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Technological Echolocation
• Replicates the concept of biological echolocation using technological devices.
• Utilizes sound waves, typically generated by artificial sources such as sonar or ultrasonic
sensors.
• These devices emit sound waves and analyze the echoes that bounce back from objects.
• The information from the echoes is processed and interpreted by the technology togenerate
useful data, such as distance, location, and object recognition.
• Technological echolocation has applications in various fields, including navigation,
robotics, obstacle detection, and medical imaging.
• It is a human-engineered solution inspired by the natural abilities of animals.
Principle of Echolocation
Both biological and technological echolocation rely on the same basic principles and have the
same underlying purpose: to determine the location, distance, and shape of objects in the
environment using sound waves and their echoes.
The principle of echolocation is based on the emission of sound waves and the interpretation of the
echoes that bounce back from objects in the environment.

Figure representing echolocation in bats and dolphins.

Mechanics:
Vision and hearing are akin in that each interprets detections of reflected waves of energy. Vision
processes light waves that travel from their source, bounce off surfaces throughout the
environment and enter the eyes. Similarly, the auditory system processes sound waves as they
travel from their source, bounce off surfaces, and enter the ears. Both neural systems can extract a
great deal of information about the environment by interpreting the complex patterns of reflected
energy that their sense organs receive. In the case of sound, these waves of reflected energy are
referred to as echoes.
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Comparing the Sound Emission and Reception in Biological Ecosystem and Technological
Ecosystem
In biological systems, sound emission and sensory reception organs are specialized adaptations that
allow animals to engage in echolocation. Technological systems, on the other hand, employ devices
designed to replicate and enhance these abilities.
Here's a concise comparison of sound emission and sensory reception organs/devices in biological
and technological systems:

Biological System Technological System

Biological organisms, such as bats and Technological systems rely on artificial

cetaceans, have specialized sound emission sound emission devices, such as speakers
organs to produce sounds for echolocation. or transducers, to generate sound waves
for echolocation.
Sound Bats emit sounds using their larynx and Ultrasonic sensors or sonar systemsemit
Emission modify the emitted sounds using structures sound waves through these devices,
like the nose leaf or mouth cavity. typically using piezoelectric elements or
transducers.
Dolphins and whales emit sounds through
their blowholes, producing clicks or
vocalizations.
Biological organisms possess specialized Technological systems use sensors and
sensory reception organs that allow them to receivers to capture and process the
detect and interpret the returning echoes. returning echoes.
Bats have highly sensitive ears designed to Ultrasonic sensors are commonly
detect and analyze ultrasonic frequencies. employed, which consist of a transducer
that emits sound waves and receives the
echoes.
Sensory
Reception
Dolphins and some whales also receive Sonar systems often incorporate
echoes through their lower jaw. The hydrophones or other specialized
jawbone conducts sound vibrations to the underwater microphones to detect and
middle ear, where they are converted into interpret the echoes.
nerve impulses for interpretation by the
brain.

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ULTRASONOGRAPHY:
Ultrasound:
Ultrasound refers to sound above the human audible limit of 20 kHz. Ultrasound of frequencies upto
10 MHz and beyond is used in medical diagnosis, therapy, and surgery. In investigative
applications, an ultrasound source (transmitter) directs pulses into the body.
When the pulse encounters a boundary between organs or between two tissue regions of different
densities, reflections of sound occur. By scanning the body with Ultrasound and detecting echoes
generated by various organs, a sonogram of the internal structure(s) can be generated. The
method is called diagnostic imaging by echolocation.

(Sonography of Kidney)
Diagnostic ultrasound, also called sonography or diagnostic medical sonography, is an imaging
method that uses sound waves to produce images of structures within your body. The images can
provide valuable information for diagnosing and directing treatment for a variety of diseases and
conditions.
Ultrasonography is a medical imaging technique that uses high-frequency sound waves to produce
images of the internal organs and tissues of the body. It is also known as ultrasound imaging or
sonography.
The ultrasound machine emits high-frequency sound waves (usually in the range of 2 to 18 MHz)
that travel through the body and bounce back off of the internal organs and tissues. The returning
echoes are captured by the ultrasound machine and used to create images of the internal structures.
Ultrasonography is a non-invasive, safe, and painless imaging method that can be used to visualize
a wide range of structures within the body, including the organs of the abdomen, pelvis, and chest,

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as well as the uterus, fetus, and other soft tissues. It is commonly used in prenatal careto monitor
the growth and development of the fetus and to diagnose any potential problems.

Representing working principle of ultrasonography

Working Principle of Ultrasonography
The working principle of ultrasonography is based on the reflection of high-frequency sound waves.
Transducer: An ultrasonography machine consists of a transducer that is used to emit and receive
high-frequency sound waves. The transducer is placed in direct contact with the skin or inserted into
the body through a gel.
Emission of sound waves: The transducer emits high-frequency sound waves (usually in the range
of 2 to 18 MHz) into the body. These sound waves travel through the body and encounter different
tissues and organs, which have different acoustic properties.
Reflection of sound waves: The sound waves encounter boundaries between different tissues and
organs and bounce back, creating echoes. The strength of the echoes depends on the acoustic
properties of the tissues and organs, such as density and stiffness.
Reception of echoes: The transducer in the ultrasonography machine receives the echoes and sends
the information to a computer, which processes the data to create images.
Image formation: The computer uses the information from the echoes to create images of the
internal organs and tissues of the body. The images are displayed on a screen, allowing the operator
to see the structure and movement of the internal organs and tissues.

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Advantages of Ultrasonography
Non-invasive: Ultrasonography does not involve any incisions or injections, making it a safe and
convenient imaging method.
No ionizing radiation: Ultrasonography does not use ionizing radiation, making it a safer option for
patients, especially pregnant women and children.
Real-time imaging: Ultrasonography provides real-time images that can be used to monitor the
movement and function of internal organs and tissues in real-time.
Portable: Ultrasonography machines are portable and can be used in a variety of settings, making it
a valuable tool for emergency and rural medicine.
Cost-effective: Ultrasonography is a cost-effective imaging method that does not require any special
preparation or recovery time.
Versatile: Ultrasonography can be used to image a wide range of structures within the body,
including the organs of the abdomen, pelvis, and chest, as well as the uterus, fetus, and other soft
tissues.

SONARS:
Sonar (Sound Navigation and Ranging or Sonic Navigation and Ranging) is a technique that uses
sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances
(ranging), communicate with or detect objects on or under the surface of the water, such as other
vessels.
“sonar” can refer to one of two types of technology:
Passive sonar means listening for the sound made by vessels
Active sonar means emitting pulses of sounds and listening for echoes.

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Working Principle of Sonars

The working principle of sonar technology is based on the reflection of sound waves. Here's how it
works:
Transmitter: A sonar system consists of a transmitter that produces and emits a series of sound
pulses into the water. These sound pulses are typically in the form of high- frequency, low-power
acoustic signals, known as "ping."
Propagation of sound waves: The sound pulses propagate through the water, traveling to the target
object and bouncing back as echoes. The speed of sound in water is higher than in air, and it depends
on the temperature, pressure, and salinity of the water.
Receiver: The sonar system also includes a receiver that listens for the returning echoes. The receiver
is typically placed far away from the transmitter to minimize interference from the transmitted
signals.
Calculation of range: The time it takes for the echoes to return to the receiver is used to calculate
the range to the target object. The range is simply the product of the speed of sound in water and the
time it takes for the echoes to return.
Determination of target properties: The frequency and pattern of the echoes are used to determine
the properties of the target object, such as its size, shape, and composition. For example, a large,

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solid object will produce a strong, low-frequency echo, while a small, porous object will produce a
weaker, high-frequency echo.
Display of results: The results of the sonar measurement are typically displayed on a screen or other
output device, allowing the operator to visualize the target object and its location.
Advantages of Sonar Technology
Versatility: Sonar technology is versatile and can be used in a variety of applications, such as
underwater navigation, mapping, and imaging, as well as for military and scientific purposes.
Cost-effective: Compared to other underwater imaging technologies, sonar is relatively cost-
effective and affordable.
Non-invasive: Unlike other imaging technologies, such as diving and remote-operated vehicles,
sonar does not physically disturb the underwater environment, making it an ideal choice for
environmental monitoring and scientific research.
Real-time imaging: Sonar provides real-time imaging, allowing operators to quickly and easily
assess the underwater environment.
High resolution: Modern sonar systems have high-resolution capabilities, allowing for detailed
images of underwater objects and structure

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PHOTOSYNTHESIS:
Most life on Earth depends on photosynthesis. The process is carried out by plants, algae, and some
types of bacteria, which capture energy from sunlight to produce oxygen (02) and chemical energy
stored in glucose (a sugar). Herbivores then Obtain this energy by eating plants, and carnivores
obtain it by eating herbivores.

The Process:
During photosynthesis, plants take in carbon dioxide (CO2) and water (H20) from the air and soil. Within
the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced,
meaning it gains electrons. This transforms the water into oxygen and the carbon dioxide into glucose.
The plant then releases the oxygen back into the air, and stores energy within the glucose molecule.
In plants, photosynthesis takes place in the chloroplasts of the cells located in the leaves.
The process starts with the absorption of light energy by pigments such as chlorophyll, which then
excites electrons. These excited electrons are used to power the transfer of carbon dioxideinto
organic molecules, such as sugars and starches, through a series of chemical reactions. The end
product of photosynthesis in plants is stored chemical energy in the form of organic compounds.

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In some animals, such as algae, photosynthesis also takes place in chloroplasts. The process is
essentially the same as in plants, with the absorption of light energy and the conversion of
carbon dioxide into organic molecules.
Chlorophyll:
Inside the plant cell are small organelles called chloroplasts, which store the energy of sunlight.
Within the thylakoid membranes of the chloroplast is a light-absorbing pigment called chlorophyll, which
is responsible for giving the plant its green color. During photosynthesis, chlorophyll absorbs
energy from blue- and red-light waves and reflects green-light waves, making the want appear green.

PHOTOVOLTAIC CELLS:
WHAT IS PHOTOVOLTAIC?
The sun’s copious energy is captured by two engineering systems: photosynthetic plant cells
and photovoltaic cells (PV). Photosynthesis converts solar energy into chemical energy, delivering
different types of products such as building blocks, biofuels, and biomass; photovoltaics turn it into
electricity which can be stored and used to perform work.
The connection between photosynthesis and photovoltaics lies in the conversion of light energy into
usable forms of energy. In photosynthesis, light energy from the sun is converted into chemical
energy stored in organic molecules, such as sugars and starches. In photovoltaics, light energy is
converted into electrical energy.
Both photosynthesis and photovoltaics use the same basic principle of converting light energy into
usable forms of energy, but the end products are different. In photosynthesis, the end product is
stored chemical energy, while in photovoltaics, the end product is electrical energy. However, the
similarities between photosynthesis and photovoltaics go beyond just the conversion of light energy.
Both processes also involve the use of specialized components and materials, such as chlorophyll in
photosynthesis and silicon in photovoltaics, to absorb and convert light energy into usable forms of
energy.
The development of photovoltaics has been heavily influenced by the natural process of
photosynthesis, and many researchers have sought to mimic and improve upon the efficiency and
effectiveness of photosynthesis in order to develop more advanced and efficient photovoltaic
systems. The study of photosynthesis has thus played a significant role in the development
ofsustainable energy systems and continues to be an important area of research in the field of
renewable energy.

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(Photovoltaic cell )
A solar cell or, photovoltaic cell is an electronic device that converts the energy of light
directly into electricity by the photovoltaic effect, which is a physical and chemical
phenomenon. It is a form of photoelectric cell, defined as a device whose electrical
characteristics, such as current, voltage, or resistance, vary when exposed to light.
Individual solar cell devices are often the electrical building blocks of photovoltaic
modules, known colloquially as solar panels. The common single-junction silicon
solar cell can produce a maximum open -circuit voltage of approximately 0.5 volts to 0.6
volts.
Application:
• Remote Locations
• Stand-Alone Power
• Power in space
• Building -Related Needs
• Military Uses.
• Transportation

BIONIC LEAF:
The bionic Leaf is a biomimetic system that gathers solar energy via photovoltaic cells that can be
stored or used in several different functions. Bionic leaves can be composed of both synthetic (metals,
ceramics, polymers, etc.) and organic materials (bacteria), or solely made of synthetic materials. The
Bionic Leaf has the potential to be implemented in communities, such as urbanized areas to provide
clean air as well as providing needed clean energy.

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Mechanics:
Natural Photosynthesis vs. The Bionic Leaf at its simplest form.
In natural photosynthesis, photosynthetic organisms produce energy-rich organic molecules
from water and carbon dioxide by using solar radiation. Therefore, the process of
photosynthesis removes carbon dioxide, a greenhouse gas, from the air. Artificial
photosynthesis, as performed by the Bionic Leaf, is approximately 10 times more efficient than
natural photosynthesis. Using a catalyst. the Bionic Leaf can remove excess carbon dioxide in
the air and convert that to use alcohol fuels. like isopropanol and iso butanol.
The efficiency of the Bionic Leaf’s artificial photosynthesis is the result of bypassing obstacles
in natural photosynthesis through its artificiality. In natural systems, numerous energy
conversion bottlenecks limit the overall efficiency of photosynthesis. As a result, most plants
do not exceed 1% efficiency and even microalgae grown in bioreactors do not exceed 3%.
Existing artificial photosynthetic solar-to-fuels cycles may exceed natural efficiencies but
cannot complete the cycle via carbon fixation. When the catalysts of the Bionic Leaf are coupled
with the bacterium Ralstonia eutropha, this results in a hybrid system capable of carbon dioxide
fixation. This system can store more than half of its,input energy as products of carbon dioxide
fixation. Overall, the hybrid design allows for artificial photosynthesis with efficiencies
rivaling that of natural photosynthesis.
Components of Bionic Leaf
A bionic leaf is a biohybrid system that mimics the natural process of photosynthesis to convert
sunlight into chemical energy. It typically consists of several key components that work
together to facilitate this conversion. Here are the main components of a bionic leaf:
Photosynthetic Organism: The bionic leaf utilizes a photosynthetic organism, such as a
cyanobacterium or a genetically modified plant, as the primary component. This organism
contains chlorophyll or other light-absorbing pigments that capture solar energy and initiate
the photosynthetic process.
Light Harvesting System: The bionic leaf includes a light harvesting system, which can be
artificial or natural, to efficiently capture sunlight. In some designs, light-absorbing dyes or
semiconductor materials are incorporated to enhance light absorption and conversion
efficiency.

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Catalysts: The bionic leaf incorporates catalysts, such as enzymes (Examples: Hydrogenase,
Nitrogenase, etc.) or synthetic catalysts (Example: Rubisco (Ribulose-1,5- bisphosphate
carboxylase/oxygenase)), to facilitate the chemical reactions involved in photosynthesis. These
catalysts play a crucial role in splitting water molecules, generating electrons, and catalyzing
the conversion of carbon dioxide into fuels or other chemical compounds.
Electron Transfer Pathway: An electron transfer pathway is an essential component of the
bionic leaf system. It allows the generated electrons from water splitting to be efficiently
transported to the catalysts involved in carbon dioxide reduction or other chemical reactions.
This pathway ensures the flow of electrons necessary for fuel production or other desired
chemical transformations.
Carbon Dioxide Source: To sustain the photosynthetic process, a bionic leaf requires a source
of carbon dioxide. This can be obtained from various sources, including ambient air, industrial
emissions, or concentrated carbon dioxide solutions.
Energy Storage or Conversion System: The bionic leaf includes an energy storage or
conversion system to capture and store the chemical energy produced during photosynthesis.
This can involve the production of hydrogen gas, liquid fuels, or other energy-rich compounds
that can be stored and used as needed.
Control and Monitoring System: To optimize performance and ensure efficient operation, a
bionic leaf typically incorporates a control and monitoring system. This system monitors
various parameters such as light intensity, temperature, pH, and carbon dioxide levels, and
allows for adjustments and optimization of the overall process.
Applications:
Renewable Energy Production: One of the primary applications of bionic leaf technology is
in the production of renewable energy. Bionic leaf systems can harness solar energy and
convert it into chemical energy in the form of hydrogen gas or other carbon-based fuels. These
fuels can be used as clean energy sources for various applications, including transportation,
electricity generation, and heating.
Agriculture and Food Production: Bionic leaf technology can have applications in
agriculture and food production. By utilizing sunlight and carbon dioxide, bionic leaf systems
can generate oxygen and energy-rich compounds that can enhance plant growth and improve
crop yields. This technology can potentially contribute to sustainable agriculture practices and
help address global food security challenges.
Environmental Remediation: Bionic leaf technology has the potential to aid in environmental
remediation efforts. By utilizing the energy generated from sunlight, bionic leaf systems can
power processes that remove pollutants or contaminants from air, water, or soil, contributing
to the restoration and preservation of ecosystems.

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BIRD FLYING:
Birds fly by flapping their wings and using their body weight and the movement of the air to
stay aloft. They navigate using a combination of visual cues, the Earth's magnetic field, and
celestial navigation. Aircraft, on the other hand, use engines to generate thrust and lift from the
wings to stay in the air. They navigate using a combination of instruments and systems,
including GPS (Global Positioning System), which uses satellite signals to determine the
aircraft's position and help it navigate. Although birds and aircraft both fly, their mechanisms
and methods of navigation are quite different.
Birds flying influenced the invention of aircraft in that early aviation pioneers, such as the
Wright brothers, observed and studied the flight of birds to develop their flying machines.
They noted how birds used their wings and body to achieve lift and control their flight, and
used this knowledge to design and improve aircraft.
The development of GPS technology was not directly influenced by birds, but rather by the
need for accurate and reliable navigation systems for various purposes, including aviation.
GPS uses a network of satellites to provide location and time information, which is used by
aircraft for navigation, communication, and safety purposes.

GPS( Global Positioning System):

GPS (Global Positioning System) is a technology that uses a network of satellites to provide
location and time information to users. The technology works by measuring the time it takes
for signals to travel from satellites to a receiver on the ground or in a vehicle, and using this
information to calculate the user's position.
Here are some key components of GPS technology:
Satellites: The GPS satellite network consists of 24-32 satellites orbiting the Earth. These
satellites continuously broadcast signals containing information about their location, time,
and status.
Receivers: GPS receivers, which are typically integrated into devices such as smartphones,
navigation systems, and aircraft, receive signals from GPS satellites and use the information
to calculate the user's position.
Control segment: The control segment consists of ground-based monitoring stations that
track the GPS satellites, check the accuracy of their signals, and make adjustments as needed.

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User segment: The user segment consists of the GPS receivers used by individuals and
organizations to obtain location and time information.

GPS technology has a wide range of applications, including navigation, mapping, surveying,
search and rescue, and military operations. The accuracy and reliability of GPS have improved
over time, and the technology continues to evolve with new developments in satellite and
receiver technology, as well as the integration of GPS with other technologies such as
augmented reality and artificial intelligence.

Importance Of GPS Technology in Aircrafts

Representing GPS technology in aircrafts

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Positioning and Navigation: GPS helps aircraft accurately determine their position and follow
precise routes. Signals from satellites are received by GPS receivers onboard, allowing the
system to calculate the aircraft's position.
Flight Planning: GPS assists pilots and planners in creating optimal flight plans, considering
waypoints, altitudes, and current information on navigation aids, weather, and airspace
restrictions.
Approach and Landing: GPS-based navigation systems provide precise guidance during
approach and landing, even in low visibility. This enhances safety and reduces reliance on
ground-based navigation aids.
Air Traffic Management: GPS is integrated into air traffic management systems, improving
airspace efficiency, reducing congestion, optimizing routing, and enhancing aircraft tracking
and situational awareness for controllers.
Collision Avoidance: GPS contributes to collision avoidance systems like TCAS and ADS-B.
These systems use GPS data to track nearby aircraft, provide alerts, and ensure safe separation.
Flight Data Recording: GPS data is often recorded by flight data recording systems, aiding
post-flight analysis, accident investigation, and overall flight safety improvements.GPS
technology has revolutionized aircraft navigation and has become an integral part of modern
aviation. It provides accurate positioning, enhances safety, improves operational efficiency, and
contributes to the overall advancement of the aviation industry.
GPS AND BIRD FLIGHT:
Scientists have long known that birds navigate using the earth’s magnetic field. Now, a new
study has found subtle mechanics in the brain of pigeons that allow them to find their way.
A team at Baylor College of Medicine in the U.S. identified a group of 53 cells in a pigeon's
brain that record detailed information on the Earth's magnetic field, a kind of internal global
positioning system (GPS).
Experiment:
Prof. Dickman and his colleague Le-Qing-Wu set up an experiment in which pigeons were held
in a dark room and used a 3D coil system to cancel out the planet's natural geomagnetic
field and generate a tunable, artificial magnetic field inside the room. While they adjusted
the elevation angles and magnitude of their, artificial magnetic field, they simultaneously
recorded the activity of the 53 neurons in the pigeons' brains which had already been identified
as candidates for such sensors.
Comparing Birds and Aircrafts with GPS Technology for Navigation

Criteria Aircrafts Birds

Mechanism GPS technology in aircraft relies on Birds use a combination of visual
signals received from satellites to cues, magnetic fields, landmarks, and
determine precise position, velocity, celestial navigation to navigate and
and time. orient themselves during flight.

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Accuracy GPS technology provides highly Birds have remarkable navigational

accurate position information with a abilities but may not possess the same
margin of error typically within a level of accuracy as GPS. However,
few meters. birds can adjust their flight path based
on real-time environmental cues,
which allows for more dynamic and
adaptable navigation
Sensory GPS technology relies solely on Birds integrate various sensory inputs
Input receiving satellite signals for navigation. They can perceive and
interpret visual cues, such as
landmarks and the position of the sun
or stars, and they may also have
sensitivity to Earth's magnetic field,
enabling them to navigate across vast
distances.
Adaptability GPS technology in aircraft provides Birds, on the other hand, demonstrate
consistent and reliable navigation remarkable adaptability in their
regardless of the environmental navigation abilities. They can adjust
conditions ortime of day their flight paths based on changing
weather conditions, wind patterns,
and other factors, which allows for
efficient long-distance migration and
navigation through complex
landscapes.
Evolutionary GPS technology is a human- made Birds, however, have evolved over
Aspect innovation designed to enhance millions of years, developing
navigation and safety in aircraft. specialized neural and physiological
adaptations that enable them to
navigate and fly efficiently in diverse
habitats.

AIRCRAFT:

MECHANISM:
Lift, Drag, and Thrust: The fundamentals of bird night are similar to those of aircraft, in
which the aerodynamic forces sustain night lilt, drag, and thrust. Lift force is produced by
the action of airflow on the wing, which is an airfoil. The airfoil is shaped such that the air
provides a net upward force on the wing, while the movement of air is directed downward.
The additional net lift may come from airflow around the bird's body in some species,
especially during intermittent flight while the wings are folded or semi-folded (cf. lilting body).
Aerodynamic drag is the force opposite to the direction of motion, and hence the source of
energy loss in flight. The drag force can be separated into two portions, lift-induced drag,
which is the inherent cost of the wing producing lift (this energy ends up primarily in the wingtip
vortices), and parasitic drag, including skin friction drag from the friction of air and body
surfaces and form drag from the bird's frontal area. The streamlining of the bird's body and

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Wings reduces these forces. Unlike aircraft, which have engines to produce thrust, birds flap
their wings with a given flapping amplitude and frequency to generate thrust.
Lift, Drag, and Thrust:
• Thrust is a force that moves an aircraft in the direction of the motion. It is created with
a propeller, jet engine, or rocket. Air is pulled in and then pushed out in an opposite
direction. One example is a household fan.
• Drag is the force that acts opposite to the direction of motion. It tends to slow an object.
Drag is caused by friction and differences in air pressure. An example is putting your
hand out of a moving car window and feeling it pull back.
• Weight is the force caused by gravity.
• Lift is the force that holds an airplane in the air. The wings create most of the lift used
by airplanes.
The way the four forces act on the airplane make the plane do different things. Each force has
an opposite force that works against it. Lift works opposite of weight. Thrust works opposite
of drag. When the forces are balanced, a plane flies in a level direction. The plane goes up if
the forces of lift and thrust are more than gravity and drag. If gravity and drag are bigger than
lift and thrust, the plane goes down. Just as drag holds something back as a response to wind
flow, lift pushes something up. The air pressure is higher on the bottom side of a wing, so it is
pushed upward.

Bio Mimicking Birds fly for Aircraft Technology

Biomimicry, or the practice of using designs and processes found in nature to solve human
problems, has led to the development of various technologies inspired by birds' flight. Some
examples include:
Wing design: The shape of bird wings has inspired the design of aircraft wings, which have
evolved to be more aerodynamic and fuel-efficient as a result. The study of bird flight has
also led to the development of winglets, small structures at the tip of wings that reduce drag
and increase lift.

(Comparing the wing design of bird and aircraft)

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Flapping-wing drones: Researchers have developed drones that use flapping wings to fly,
mimicking the way birds and insects fly. These drones can be used for various applications,
such as monitoring crops and wildlife, inspecting buildings and infrastructure, and search and
rescue operations.

(Image of a flapping wind drone)

Soaring algorithms: Soaring refers to the flight technique used by birds and certain aircraft
to stay aloft and travel long distances with minimal energy expenditure. It involves utilizing
rising air currents, such as thermals, ridge lift, wind shear, or atmospheric waves, to gain
altitude and maintain flight. Birds use thermals, or columns of rising warm air, to gain altitude
and soar. Researchers have developed algorithms inspired by bird flight to help gliders and
other aircraft use thermals more efficiently, leading to longer and more sustainable flights.
Landing gear: The legs and feet of birds have inspired the design of landing gear for aircraft,
with shock-absorbing and retractable structures that help absorb impact upon landing.

LOTUS LEAF EFFECT

The lotus leaf is well-known for having a highly water repellent, or superhydrophobic,
surface, thus giving the name to the lotus effect. Water repellency has received much
attention in the development of self-cleaning materials, and alias been studied in both
natural and artificial systems.
The lotus leaf effect, also known as the "lotus effect," refers to the ability of lotus leaves to
repel water and self-clean through their unique surface structure. This effect has inspired the
development of super hydrophobic and self-cleaning surfaces, which have a wide range of
applications in various industries.
The lotus leaf surface has a microscale and nanoscale structure that consists of numerous small
bumps and wax-coated hairs. This structure creates a high contact angle between the water
droplets and the surface, causing the droplets to roll off and carry away any dirt or debris. This
self-cleaning property is due to the lotus leaf's ability to repel water and resist adhesion.

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(Representing the surface of lotus leaf )

Super hydrophobic and self-cleaning surfaces have applications in industries such as

aerospace, automotive, building materials, and medical devices. For example, self-cleaning
coatings can be used on the exterior of buildings to reduce the need for cleaning and
maintenance, while super hydrophobic coatings can be used to prevent icing on aircraft wings.
SUPERHYDROPHOBIC AND SELF-CLEANING SURFACES:
The self-cleaning function of superhydrophobic surfaces is conventionally attributed
to the removal of contaminating particle by impacting or rolling water droplets, which
implies the action of external forces such as gravity. Here, we demonstrate a unique self-
cleaning mechanism whereby the contaminated superhydrophobic surface is exposed to
condensing water vapor, and the contaminants are autonomously removed by the self-
propelled jumping motion of the resulting liquid condensate, which partially covers or fully
encloses the contaminating particles. The jumping motion of the superhydrophobic surface
is powered by the surface energy released upon the coalescence of the condensed water phase
around the contaminants. The jumping-condensate mechanism is shown to spontaneously
clean superhydrophobic cicada wings, where the contaminating particles cannot be
removed by gravity, wing vibration, or wind flow. Our findings offer insights into the
development of self-cleaning materials.
Mechanism:
An autonomous mechanism to achieve self-cleaning on superhydrophobic surfaces, where
the contaminants are removed by self-propelled jumping condensate powered by surface
energy. When exposed to condensing water vapor, the contaminating particles arc either fully
enclosed or partially covered with the resulting liquid condensate. Building upon our
previous publications showing self-propelled jumping upon drop coalescence, we
show particle removal by the merged condensate drop with a size comparable to or
larger than that of the contaminating particle(s). Further, we report a distinct jumping
mechanism upon particle aggregation, without a condensate drop of comparable size to
that of the particles, where a group of particles exposed to water condensate clusters
together by capillarity and self-propels away from the superhydrophobic surface.

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PLANT BURRS and VELCRO:

Plant burrs, such as those found on burdock, inspired the invention of Velcro, a popular
hook-and-loop fastening system.

a) b)
a) The globular flower heads of burdock b) indicating the hook shape
The burrs have small hooks that can latch onto clothing, fur, or feathers, allowing them to
disperse their seeds over a wider area.

a) hook and loops normal view of Velcro b) microscopic view of hooks and loops of velcro

Velcro was invented by Swiss engineer George De Mestral in 1941, after he becamefascinated
by the way burrs clung to his clothes and his dog's fur during a walk. He examined the burrs
under a microscope and found that they had small hooks thatcould latch onto loops in
fabric. De Mestral spent years experimenting with different materials before finally developing
Velcro, which consists of two strips of nylon fabric, one with tiny hooks and the other with
small loops. When pressed together, the hooks latch onto the loops, creating a strong bond that
can be easily detached by pulling the two strips apart. Velcro has a wide range of applications,
including in clothing, shoes, bags, and medical devices. It has become a popular alternative to
traditional fasteners, such as buttons and zippers, due to its ease of use and versatility.
The name "Velcro" is actually a combination of the words "velvet" and "crochet," as the fabric
strips resemble velvet and are hooked together like crochet. Velcro has since become a popular
alternative to traditional fasteners, such as buttons and zippers, due to its ease of use and
versatility.

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Relevance to humans:
Burrs are best known as sources of irritation, injury to livestock, damage to clothing, punctures
to tires and clogging equipment such as agricultural harvesting machinery. Furthermore,
because of their ability to compete with crops over moisture and nutrition. Bur plants can be
labels as weeds and therefore also be subject to removal. Methods of controlling the spread of
bur plants include the use of herbicides, slashing and cultivation among others.
Some have however been used for such purposes as fabric fulling, for which fuller’s teasel is a
traditional resource. The bur of burdock was the inspiration for the hook and loop fastener also
Known as Velcro.

Engineering Applications of Velcro Technology

Clothing and Footwear: Velcro is commonly used in clothing and footwear for closures
and adjustable straps. It can be easily opened and closed, making it convenient for users with
limited dexterity or mobility.
Medical devices: Velcro is used in medical devices such as braces, splints, and compression
garments forits adjustable and secure fastening capabilities.
Aerospace equipment: Velcro is used in aerospace equipment, such as satellites and
spacecraft, to secure components in place and prevent them from vibrating or shifting during
launch or flight.
Automotive industry: Velcro is used in the automotive industry for a range of applications,
such as securing carpets and headliners, and attaching door panels and seat cushions.
Packaging industry: Velcro is used in the packaging industry for resealable closures on bags,
pouches, and other types of packaging.
Sports equipment: Velcro is used in sports equipment, such as helmets and gloves, for its
ability to provide a secure and adjustable fit.

Shark skin and friction reducing Swin Suits

The denticles on shark skin have evolved over millions of years to reduce drag and increase
swimming efficiency. These structures disrupt the flow of water around the shark's body,
reducing turbulence and minimizing the formation of vortices. As a result, sharks can swim
faster and with less effort compared to other fish.

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Figure: Indicating the denticles on shark skin

Denticles on shark skin are like tiny bumps or ridges. They disrupt the flow of water around
the shark's body, making it smoother and reducing turbulence. This disruption reduces the
resistance the shark experiences as it swim, allowing it to move faster and with less effort.
Turbulence in Water:
Turbulence is when a fluid, like water or air, becomes chaotic and unpredictable. Instead of
flowing smoothly, it swirls and forms irregular patterns. This turbulence creates resistance or
drag, which makes it harder for things to move through the fluid. In swimming, reducing
turbulence is important because it helps to minimize resistance, allowing swimmers to move
more easily and efficiently through the water.
Reducing Drag:
When a shark swims through the water, the water normally flows smoothly over its body.
However, the denticles on the shark's skin disrupt this smooth flow. They create small
disturbances in the water, which helps to break up turbulent currents that can slow the shark
down. By reducing turbulence, the denticles make the flow of water around the shark's body
smoother. This smoother flow reduces the resistance or drags the shark experiences as it moves
through the water, allowing it to swim more efficiently.
Frictionless Swim Suits:
Shark skin has inspired the development of friction-reducing swim suits, which are designed
to improve the performance of swimmers by reducing drag in the water.
Friction-reducing swim suits use a similar structure to that of shark skin to reduce drag and
improve swimmer performance. These suits are made from high-tech materials that mimic
the properties of shark skin, such as the shape and size of the denticles.

Materials Used
The materials used to create friction-reducing swim suits inspired by shark skin include:
Polyurethane: A type of polymer that is commonly used in the production of swim suits,
asit is durable and can be molded into a variety of shapes.
Lycra/Spandex: Lycra and spandex are made from the same synthetic fiber, which is
technically called elastane. Elastane fibers are typically composed of a polymer called
polyurethane which is then blended with other fibers like nylon, polyester, or cotton) that is
known for its stretch and flexibility.
High-tech fabrics: A range of high-tech fabrics have been developed specifically for use in
swim suits. These fabrics are designed to be lightweight, water-repellent, and hydrodynamic,
and often incorporate materials such as silicone or Teflon to reduce drag.

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Kingfisher Beak and Bullet Train

Figure: Indicating the shape similarities of kingfisher beak and design of the front of the bullet
train
The kingfisher beak is an excellent example of nature's design for efficient diving and fishing.
Its unique shape and structure enable the kingfisher to minimize the impact of water resistance
and achieve a successful dive.

The Physics behind the Kingfisher Beak

Streamlining:
The beak of a kingfisher is long, slender, and sharply pointed, which helps reduce drag or air
resistance as the bird dives into the water. The streamlined shape allows the kingfisher to
smoothly cut through the air and minimize the energy required for the dive.
Surface Tension:
When the kingfisher hits the water, it encounters the resistance caused by surface tension.
Surface tension is the cohesive force between water molecules that creates a "skin" on the
water's surface. The sharp beak of the kingfisher helps to pierce through the water's surface,
breaking the surface tension and reducing the force required to enter the water.
Minimizing Splash:
As the kingfisher dives, it needs to enter the water with minimal disturbance to avoid scaring
away the fish it intends to catch. The shape of the beak helps to reduce the splash generated
upon entry. The beak's narrow and pointed design helps create a smooth entry by
minimizing the disturbance of the water surface, allowing the kingfisher to enter silently and
effectively.

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image of shinkasen bullet train of Japan

Technological Importance : The use of the kingfisher beak as a design inspiration for the front
of the bullet train is an example of how nature-inspired engineering can lead to innovative
solutions that improve the performance and efficiency of machines. Shinkansen bullet train of
Japan is the best example which used the biomimicry of kingfisher’s beak.
Aerodynamic Design: The front of the Shinkansen is meticulously shaped to reduce air
resistance and improve aerodynamic performance. The streamlined design minimizes drag as
the train travels at high speeds, allowing it to maintain stability and efficiency. The smooth,
tapered shape reduces the pressure difference between the front and rear of the train, reducing
noise and vibration.
Pressure Wave Reduction: When a high-speed train moves through a tunnel, it creates
pressure waves that can cause noise and discomfort for passengers. The nose of the Shinkansen
is designed to reduce these pressure waves by effectively managing airflow and minimizing
the compression and expansion of air as the train enters and exits tunnels. This reduces the
noise level and enhances passenger comfort.

HUMAN BLOOD SUBSTITUTES:

Shortages in blood supplies and concerns about the safety of donated blood have fueled the
development of so-called blood substitutes. The two major types of blood substitutes are
volume expanders, which include solutions such as saline that are used to replace lost plasma
volume, and oxygen therapeutics, which are agents designed to replace oxygen normally
carried by the haemoglobin in red blood cells. Of these two types of blood substitutes, the
development of oxygen therapeutics has been the most challenging. One of the first groups of
agents developed and tested were perfluorocarbons, which effectively transport and deliver
oxygen to tissues but cause complex side effects, including flulike reactions and are not
metabolized by the body.
Blood from the human umbilical cord has been studied for its potential as a substitute source
of red blood cells for transfusion. Red blood cells can be extracted from cord blood via

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sedimentation as the blood is cooled. Donated cord blood can be screened for infections
organisms and other contaminants. Research concerning its potential use for transfusion is
ongoing. Of particular concern for implementation are the establishment of safe, effective and
ethical procedures for cord blood collection as well as the development of criteria that help to
ensure safe transfusion and the preservation of cord blood quality.
Haemoglobin-based oxygen carriers (HBOCs) AND Perfluorocarbons(PFC):
Pharmaceutical companies attempted to develop HBOCs ( also called oxygen therapeutics) and
PFCs starting in the 1980 and at first ,seemed to have some success .However ,the results of
most human clinical trials have been disappointing. A study published in 2008 in the journal of
the American Medical Association summarized the results of 16 clinical trials on five different
blood substitutes administered to 3,500 patients.
Those receiving blood substitutes had a threefold increase in the risk of heart attacks compared
with the control group given human donor blood. However, a closer analysis of the results
showed that some of the negative statistics were misleading. The artificial blood products
reviewed in this study varied in their benefits and risks, and some blood substitutes had very
few serious side effects. The findings suggest that some blood substitutes may be safer and
more beneficial than scientists originally thought.
1) HBOCs:
Haemoglobin-based oxygen carriers (HBOCs) are “made of”’ natural haemoglobins that were
originally developed as blood substitutes but have been extended to a variety of hypoxic
clinical situations due to their ability to release oxygen. Compared with traditional preservation
protocols, the addition of HBOCs to traditional preservation protocols provides more oxygen
to organs to meet their energy metabolic needs prolongs preservation time, reduces ischemia-
reperfusion injury to grafts, improves graft quality , and even increases the number of
transplantable donors. The focus of the present study was to review the potential applications
of HBOCs in solid organ preservation and provide new approaches to understanding the
mechanism of promising strategies for organ preservation.

2)PFCs:
PFCs remain in the bloodstream for about 48 hours. Because of their oxygen-dissolving ability,
PFCs were the first group of artificial blood products studied by scientists. They are first-
generation blood substitutes. Unlike the red-coloured HBOCs, PFCs are usually white.
However, since they do not mix with blood they must be emulsified before they can be given to
patients. PFCs are such good oxygen carriers that researchers are now trying to find out if they
can reduce swollen brain tissue in traumatic brain injury. PFC particles may cause flu-like-
symptoms in some patients when they exhale these compounds.

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Question bank module 4

1. Explain Echolocation with its mechanics.
2. What is ultrasonography? Explain with example.
3. What is SONARs? Explain its Types.
4. Write a note on Photosynthesis process.
5. Explain Photovoltaic cells and write its applications.
6. Explain Bionic leaf with its mechanics and write applications.
7. Write a note on GPS system and Bird flying.
8. Explain Aircraft with its mechanism and also define Lotus leaf effect.
9. Discuss the superhydrophobic and self-cleaning surfaces with its mechanism.
10. Write a note on plant burrs.
11. Explain shark skin and how it is relevance to human.
12. How kingfisher beak looks and write its relationship with humans.
13. Write the strategy and potential in the beak that inspired a bullet train.
14. Briefly explain human blood substitutes with HBOs and PFCs.

Course Title : Biology for Engineer’s.

Course Code: 21BE45
Course Coordinator : Ms. Rajashree
Department of Science & Humanities.

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