From HoD's Desk
This newsletter provides information on the events and activities that happened in July 2022. The planning of the semester and the academic year, committee formation for various activities and events, activity planning for clubs and student bodies, academic calendar, etc. happened this month with the involvement of all the faculty members. A strategic plan for achieving success on all the fronts of the department in the next five years is prepared and discussed with faculty members for their input and suggestions. The successful implementation of this is now on agenda.
Department Events
MoU with E-mmortal Automotive Pvt. Ltd., Nashik
Session on “Converting Innovation in Start-up” by Shri. Puneet Raman (27th July 2022)
Expert Session on “Engineering Project Guidance” by Mr. John Yesuraj (28th July
2022)
Celebration of 'World Nature Conservation Day (28th July)'
Student Corner
Student Placement
Placed
Students Details (July - 2022)
|
Sr. No. |
Name of the Student |
Placement Date |
Batch |
|
1 |
Purane
Pratiksha Anand |
23/07/2022 |
2021-22 |
|
2 |
Sneha Mate |
12/07/2022 |
2021-22 |
Congratulation!
Project Competition
Sports Achievement:
Industrial Visit:
Student Publication
Alumni Corner:
Faculty Corner:
Faculty Participation
Article by Dr. Ravindra Munje in Dainik Gavakari (7th July 2022)
https://gavakari.in/.../1294/gavakari--7-july-2022/page/10
Farewell to Ms. Jyoti Vadje
Industrial Training/Courses done by staff during July 2022
|
Name of Faculty |
Title of Event |
Duration |
Type of Event |
Organized by |
|
Prof. Pooja Sagar Sapkade |
Faculty
Development Program on "Embedded
Product Design " |
One week |
Offline |
K. K. Wagh Institute of Engineering
Education and Research. |
|
Prof. Snehal Sagare |
Faculty
Development Program on "Embedded
Product Design " |
One week |
Offline |
K. K. Wagh Institute of Engineering
Education and Research. |
|
Mrs.Shubhada A Borade |
Faculty
Development Program on "Embedded
Product Design ". |
One day |
Offline |
K. K. Wagh Institute of Engineering
Education and Research. |
Student Articles:
Flicker fusion threshold
Sakshi Madhav Ohol TE-A (Electrical) (sakshivohol03@gmail.com)
The flicker fusion threshold, critical
flicker frequency (CFF) or flicker fusion rate, is a
concept in the psychophysics of vision. It is defined as the frequency
at which an intermittent light stimulus appears to be completely steady to the
average human observer. A
traditional term for flicker fusion is "persistence of vision", but this has also been
used to describe positive
afterimages or motion
blur. Although flicker can be detected for many
waveforms representing time-variant fluctuations of intensity, it is
conventionally, and most easily, studied in terms of a sinusoidal modulation of
intensity.
Seven parameters determine the ability to detect
the flicker:
1.
the frequency of the modulation;
2.
the amplitude or depth of the
modulation (i.e., what is the maximum percent decrease in the illumination
intensity from its peak value);
3.
the average (or maximum—these can
be inter-converted if modulation depth is known) illumination intensity;
4.
the wavelength (or wavelength
range) of the illumination (this parameter and the illumination intensity can
be combined into a single parameter for humans or other animals for which the
sensitivities of rods and cones are known as a function of wavelength using
the luminous flux function);
5.
the position on the retina at
which the stimulation occurs (due to the different distribution of
photoreceptor types at different positions);
6.
the degree of light or dark
adaptation, i.e., the duration and intensity of previous exposure to background
light, which affects both the intensity sensitivity and the time resolution of
vision;
7.
Physiological factors such as age
and fatigue.
Explanation
As long as the modulation frequency is kept above the fusion
threshold, the perceived intensity can be changed by changing the relative
periods of light and darkness. One can prolong the dark periods and thus darken
the image; therefore the effective and average brightness are equal. This is
known as the Talbot-Plateau law. Like
all psychophysical thresholds, the flicker fusion
threshold is a statistical rather than an absolute quantity. There is a range
of frequencies within which flicker sometimes will be seen and sometimes will
not be seen, and the threshold is the frequency at which flicker is detected in
50% of trials.
Different points in the visual system have very different
critical flicker fusion rate (CFF) sensitivities; the overall threshold
frequency for perception cannot exceed the slowest of these for a given
modulation amplitude. Each cell type integrates signals differently. For
example, rod
photoreceptor cells, which are exquisitely sensitive and capable of
single-photon detection, are very sluggish, with time constants in mammals of
about 200 ms. Cones, in contrast, while having much lower
intensity sensitivity, have much better time resolution than rods do. For both
rod- and cone-mediated vision, the fusion frequency increases as a function of
illumination intensity, until it reaches a plateau corresponding to the maximal
time resolution for each type of vision. The maximal fusion frequency for
rod-mediated vision reaches a plateau at about 15 hertz (Hz), whereas
cones reach a plateau, observable only at very high illumination intensities,
of about 60 Hz.
In addition to increasing with average illumination
intensity, the fusion frequency also increases with the extent of modulation
(the maximal relative decrease in light intensity presented); for each
frequency and average illumination, there is a characteristic modulation threshold,
below which the flicker cannot be detected, and for each modulation depth and
average illumination, there is a characteristic frequency threshold. These
values vary with the wavelength of illumination, because of the wavelength
dependence of photoreceptor sensitivity, and they vary with the position of the
illumination within the retina, because of the concentration of cones in
central regions including the fovea and
the macula,
and the dominance of rods in the peripheral regions of the retina.
Visual phenomena
In some cases, it is possible to see flicker at rates beyond
2000 Hz (2 kHz) in the case of high-speed eye movements (saccades)
or object motion, via the "phantom array" effect.[19][20] Fast-moving
flickering objects zooming across view (either by object motion or by eye
motion such as rolling eyes), can cause a dotted or multicolored blur instead of
a continuous blur as if they were multiple objects.[21] Stroboscopes are
sometimes used to induce this effect intentionally. Some special effects, such
as certain kinds of electronic glowsticks commonly seen at
outdoor events, have the appearance of a solid color when motionless but
produce a multicolored or dotted blur when waved about in motion. These are
typically LED-based glow sticks. The variation of the duty cycle upon the
LED(s), results in the usage of less power while the properties of flicker
fusion have the direct effect of varying the brightness. When moved, if the
frequency of duty cycle of the driven LED(s) is below the flicker fusion
threshold timing differences between the on/off state of the LED(s) become
evident, and the color(s) appear as evenly spaced points in the peripheral
vision.
A related phenomenon is the DLP rainbow
effect, where different colors are displayed in different places on
the screen for the same object due to fast motion.
Flicker
Flicker is the perception of visual fluctuations in intensity
and unsteadiness in the presence of a light stimulus that is seen by a static
observer within a static environment. A flicker that is visible to the human
eye will operate at a frequency of up to 80 Hz.
Stroboscopic
effect
The stroboscopic effect is sometimes used to
"stop motion" or to study small differences in repetitive motions.
The stroboscopic effect refers to the phenomenon that occurs when there is a
change in perception of motion, caused by a light stimulus that is seen by a
static observer within a dynamic environment. The stroboscopic effect will
typically occur within a frequency range between 80 and 2000 Hz, though
can go well beyond 10,000 Hz for a percentage of the population.
Phantom array
Phantom array, also known as the ghosting effect, occurs when
there is a change in the perception of shapes and spatial positions of objects.
The phenomenon is caused by a light stimulus in combination with rapid eye
movements (saccades) of an observer in a static environment. Similar to the
stroboscopic effect, the phantom effect will also occur at similar frequency
ranges. The mouse arrow is a common example of the phantom array
effect.
Non-human species
The flicker fusion threshold also varies between species. Pigeons have
been shown to have a higher threshold than humans (100 Hz vs. 75 Hz),
and the same is probably true for all birds, particularly birds of prey. Many
mammals have a higher proportion of rods in their retina than humans do, and,
likely, they would also have higher flicker fusion thresholds. This has been
confirmed in dogs.
Research also shows that size and metabolic rate are two
factors that come into play: small animals with high metabolic rates tend to
have high flicker fusion thresholds.
Lightning: Lightning Storage Harvesting
Kathale Sanchit Dilip, BE-B (Electrical) (sanchitkathale30@gmail.com)
Lightning is a naturally occurring electrostatic discharge
during which two electrically charged regions, both in the atmosphere or with
one on the ground, temporarily neutralize themselves, causing the instantaneous
release of an average of one gigajoule of energy. This discharge may produce a
wide range of electromagnetic radiation, from the heat created by the rapid
movement of electrons to brilliant flashes of visible light in the form of
black-body radiation. Lightning causes thunder, a sound from the shock wave
which develops as gases in the vicinity of the discharge experience a sudden
increase in pressure. Lightning occurs commonly during thunderstorms as well as
other types of energetic weather systems, but volcanic lightning can also occur
during volcanic eruptions.
The three main kinds of lightning are distinguished by where
they occur: either inside a single thundercloud (Intra-Cloud), between two
different clouds (Cloud-to-Cloud), or between a cloud and the ground
(Cloud-to-Ground). Many other observational variants are recognized, including
“heat lightning”, which can be seen from a great distance but not heard; dry
lightning, which can cause forest fires; and ball lightning, which is rarely
observed scientifically. Humans have deified lightning for millennia. Idiomatic
expressions derived from lightning, such as the English expression “bolt from
the blue”, are common across languages. At all times people have been fascinated
by the sight and difference of lightning. The fear of lightning is called
astraphobia.
Lightning occurs when the charge builds up in a layer of
cloud in the atmosphere, inducing an electric field between the earth and the
clouds, which causes molecules in the air to become ionized, allowing the air
to become a temporary conductor to discharge the natural capacitor. This
build-up of charge occurs as a result of precipitation and the Convection
currents selectively separating charges in a Thundercloud. The Elster-Geitel
Model describes water droplets in the cloud traveling upwards as a result of
convection (itself caused In part by the heat exerted by Vaporization)
collecting positive charge from ice particles that have been polarized by an
electric field. The polarization of the ice particle means the bottom is more positive
than the top, so a neutral water droplet traveling upwards would collect some
of its positive Charge. This would cause a separation between positive and
negative charges in the cloud.
This process has positive feedback as the resulting voltage
contributes to the electric field. Of course, an Electric field must exist
beforehand, but only a small field is needed to trigger the process. A
lightning occurrence that successfully hits the earth has a stepped leader,
which is the first stroke that propagates. This stepped leader, which travels
in a stream about 45 meters long, is caused by Ionization in the clouds when
discharge occurs in the cloud layer, where there are differences in Potential.
The electrons freed from this process are attracted to the ground. As the
leader travels towards the earth it generates a channel of ionized air. Just as
the negatively charged stepped leader reaches the earth, it attracts a positive
charge from the surface of the earth towards it, inducing a large Current,
causing the air surrounding the leader to become luminous. The positive charge
then travels up this channel, illuminating the air as it goes. This is what is
known as the return stroke and is what is visible to the observer. Even though
the return stroke only illuminates the air while it is traveling, it is
perceived as a solid line because it happens too quickly for human vision to
see the movement. Due to the very intermittent properties of lightning Strikes
and also hazards involved within it, very limited research has been conducted
in Lightning energy harnessing areas Worldwide. However, the lightning-causing
clouds have very high Charge density. So, an experimental study in a numerical
Computational environment has been experimented with for Measuring the response
characteristics of lightning sparks to store The energy by real-time
environmental data collected from Various meteorological centers.
Figure 1: Lighting Image captured from Tanhirl area of Aizawl city in Mizoram
The single-stage two-level spark Generator circuit has been
used to simulate the presented system. Renewable energy is nowadays a most
popular research topic worldwide. With standard sustainable power source
Innovations like wind, hydro, solar, bio, and geothermal vitality, there are
some inexhaustible advancements accessible which are still under evolving
conditions, like tidal power. There is one more renewable energy source
available, which is Lightning Energy. Lightning energy is a renewable resource
produced from Natural lightning strikes. But due to hazards involved in
Lightning research, very limited research data on lightning Energy is available
worldwide. According to meteorological science, lightning was existing on earth
long before life evolved on our planet. Researchers found proof of the
existence of lightning before three billion years ago on this earth. This is
likewise Obvious that lightning assumed a part in delivering the natural
Particles fundamental for the development of each living thing The lightning
occurred through a few steps, they are given Below: a) Cloud Formation b)
Charge Separation c) Pilot Streamer d) Stepped Leader e) Discharge f) Return
Stroke g) Dart Leader h) Re-Strike. In the literature, lightning does have
useful energy, but practically storage of energy from lightning is a difficult
task. Many researchers already had done some research work on it. No practical
way has yet been found to harness the energy from lightning. As lightning is
consisting of high-value electrostatically charged particles, there is always
some Hazards possibility involved in the research of lightning. And Also,
lightning is very intermittent in nature, so very limited Literature is
available globally. A single lightning discharge conveys around 5 billion
joules or about the vitality put away In 145 liters of petrol. Likewise, a
lightning strike conveys around 5 billion joules on average over 10
microseconds, which Is equivalent to 500 trillion watts of power. India is not
so numerous lightning ensuing country. Cherrapunji is the most lightning
happening place in India. Cherrapunji is a sub-divisional town in the East
Khasi Hills locale in the Indian territory of Meghalaya. Cherrapunji Has oft
been considered similar to the wettest place on Earth, Yet for the time being
close-by Mawsynram as of now holds that record. Cherrapunji gets downpours from
the Bay of Bengal arm of the Indian summer rainstorm.
About Newsletter:
Declaration
Newsletter Committee
Chief
Editor: Dr. Ravindra
K. Munje, Professor and I/C HoD, Electrical Department
Staff Editor: Prof. S. Saravanan, Assistant Professor
Prof.
Priya Vyavahare, Assistant Professor
Student Editors: Anuj Paul (BE-A)
Vedika Dharaskar (BE-A)
Sharvari Phase (BE-A)
Abhishek Jadhav (BE-A)
Rutuja Kapile (BE-A)
Vaibhav Dhanokar (TE-A)
Huzaif Sayyed (TE-A)
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