##### Gravity and Spacetime: Is Gravtiy a Force?

BLOG CREDITS Jatin Nitk

At the base of classical newtonion mechanics is the notion that a body’s motion can be described as a combination of inertial motion, and deviation from this inertial motion. Such deviations are caused by external forces acting on a body in accordance with Newton’s second law of motion.

The preferred inertial motions are related to the geometry of space and time: in the standard reference frames of classical mechanics, objects in free motion move along straight lines at constant speed. In modern parlance, their paths are geodesics, straight world lines in curved spacetime. According to general theory of relativity, gravity is not a force and there are no gravitational field. General theory of relativity describes gravity not as a force, but as a consequence of masses moving along straight line path in a curved spacetime caused by uneven distribution of mass. So what exactly is this spacetime? Spacetime is any mathematical model which fuses three dimensions of space and the one dimension of time into a single four dimensional manifold. Einstein described force of gravity, in his theory of general relativity, as a consequence of the curves in the fabric of spacetime. Matter like stars and planets creates distortions in spacetime that cause it to bend.

These curves, in turn, constrict the ways in which everything in universe moves, because objects have to follow paths, geodesics, along this warped curvature. Motion due to gravity is actually motion along the twists and turns of space time. However, for most application (about 30 orders of magnitude) gravity is well approximated by Newton’s law of universal gravitation, which describes gravity as a force. This can be understood easily using an analogy between a man falling off the roof of a house and an astronaut floating in a spaceship in deep space, not near any large masses. Under general theory of relativity these two scenarios are equivalent, not just similar, where both men aren’t under any gravitational field and are perfect example of an inertial frame of reference.

Man falling off a roof would be weightless and anything dropped on his way down will remain stationary relative to him or moving in uniform motion similar to the case of astronaut in deep space where he feels no weight and all objects relative to him are in rest. There is no observable distinction between inertial motion and motion under the influence of the gravitational force

. Under classical mechanics, man falling off a roof is in gravitational field of earth but under general relativity there is no such field and man is just following a straight line path, geodesics, but because spacetime is curved around matter, in this case earth, the man seems to be accelerating at 9.8 m/s2 toward earth. Both freely falling man and astronaut are in inertial frame of reference till their motion is stopped by some other objects such as earth. Similarly objects in a gravitational field behave equivalent to objects within an accelerating enclosure. For example, an observer will see a ball fall the same way in a rocket as it does on Earth, provided that the acceleration of the rocket is equal to 9.8 m/s2 (the acceleration due to gravity at the surface of the Earth).

This is called as the “Einstein equivalence principle” which states that “The outcome of any local non gravitational experiment in a freely falling laboratory is independent of the velocity of the laboratory and its location in spacetime” or simply the gravitational “force” as experienced locally while standing on a massive body (such as the Earth) is the same as the pseudo-force experienced by an observer in a non-inertial (accelerated) frame of reference

. In conclusion, gravity is not the force of attraction that makes things fall straight down but consequence of curvature in spacetime due to matter.

##### The Indelible Impact of COVID-19 On Cybersecurity by Samyak Sanjay Sand

Article Written by Samyak Sanjay Sand – CSE at NIT Karnataka

As a result of the COVID-19 epidemic and the ensuing lockdown, more people are confined to their homes, where they have considerably more hours to spend online each day and are becoming more reliant on the Internet to receive services that they would have otherwise obtained offline.

For many years, the risks of cybercrime have been present. However, an increase in the number of Internet users mid pandemic, along with the amount of time they spend online, has presented cybercriminals with more options to use the situation to their advantage, which has, in turn, increased their potential to gain money or cause disruption. It should be noted that some of the most vulnerable groups of the population, for example, students, need to spend more time online for services like online classes.

While youngsters benefit immensely from e-learning, they are also more vulnerable to cyber risks. Not only the young but also the elderly, who used to rely on offline shopping but now have to buy what they need on the Internet, are more vulnerable to cybercrime. This tectonic change in the way we live and use the Internet has led to the proliferation of e-crimes.

Throughout the epidemic, countries worldwide reported an increase in cybercrime. For instance, in India, the Cyber and Information Security (C&IS) Division, which is responsible for cybercrime, reported a variety of scams and frauds that took the form of advertisements, emails, phoney websites, as well as phone calls and text messages. Cybercriminals are using malware, including viruses, worms, trojan horses, ransomware, and spyware, to penetrate, compromise, steal, or wipe personal data on personal computers by capitalizing on the anxieties and fears triggered by the pandemic. In addition, Italian law enforcement has identified the “Corona Anti-Virus” software.This software’s BlackNet Rat application claims to protect the user’s device from viruses but instead undermines its security and takes control, allowing the criminal to operate it remotely.

Despite the fact that the risk of being attacked will continue to exist, some mitigating methods may be beneficial to users. It is strongly advised that users use extreme caution while dealing with phishing emails and websites, exercise good cyber hygiene, connect to only trusted Wi-Fi networks, and consider using a password manager to prevent using the same password for different websites. When sharing sensitive data or downloading a file from an email, it is vital to have two separate lines of communication. Having the sender verify their identity with an SMS, WhatsApp message, or brief phone call before opening an attack email or webpage can help avert a cyberattack. When using group conference calls (MS Teams, Google Meets, Zoom, etc.), be cautious about sharing screens or transmitting images that may include sensitive information.

Ultimately, COVID-19 will forever alter our way of life through the introduction of new work styles, new cybersecurity challenges, new recommended policies, improvements in personal cleanliness, and so on. The fight against COVID-19 is not just for business, its employees, or its customers; it is a collaborative effort on everyone’s part. Consequently, post-COVID-19, users and organizations will need to re-evaluate their cyber risk management procedures, including updating network security settings, installing a good-quality VPN, and utilizing appropriate anti-virus software to ensure their system and network settings remain malware and virus-free.

##### Research paper guide on black holes

Black holes and thermodynamics

A black hole of given mass, angular momentum, and charge can have a large number of different
unobservable internal configurations which reflect the possible different initial configurations of the matter
which collapsed to produce the hole. The logarithm of this number can be regarded as the entropy of the
black hole and is a measure of the amount of information about the initial state which was lost in the
formation of the black hole. If one makes the hypothesis that the entropy is finite, one can deduce that the
black holes must emit thermal radiation at some nonzero temperature.

Conversely, the recently derived quantum-mechanical result that black holes do emit thermal radiation at temperature κℏ2πkc, where κ is thesurface gravity, enables one to prove that the entropy is finite and is equal to c3A4Gℏ, where A is the surface areaof the event horizon or boundary of the black hole. Because black holes have negative specific heat, they
cannot be in stable thermal equilibrium except when the additional energy available is less than 1/4 the mass
of the black hole. This means that the standard statistical-mechanical canonical ensemble cannot be applied
when gravitational interactions are important. Black holes behave in a completely random and time-
symmetric way and are indistinguishable, for an external observer, from white holes. The irreversibility that
appears in the classical limit is merely a statistical effect.
Particle Creation by Black Holes

In the classical theory black holes can only absorb and not emit particles. However it
is shown that quantum mechanical effects cause black holes to create and emit
particles as if they were hot bodies with temperature
hk2πk ≈ 10−6 (M⊙M) ∘Khk2πk ≈ 10−6 (M⊙M) ∘K where k is the surface gravity of the
black hole. This thermal emission leads to a slow decrease in the mass of the black
hole and to its eventual disappearance: any primordial black hole of mass less than
about 1015 g would have evaporated by now. Although these quantum effects violate
the classical law that the area of the event horizon of a black hole cannot decrease,
there remains a Generalized Second Law: S+14AS+14A never decreases never
decreases where S is the entropy of matter outside black holes and A is the sum ofthe surface areas of the event horizons.

This shows that gravitational collapse converts the baryons and leptons in the collapsing body into entropy. It is tempting to speculate that this might be the reason why the Universe contains so much entropy per baryon https://www.worldscientific.com/doi/abs/10.1142/9789814539395_0011 Evanescent black holes A renormalizable theory of quantum gravity coupled to a dilaton and conformal matter in two spacetime dimensions is analyzed. The theory is shown to be exactly solvable classically. Included among the exact classical solutions are configurations describing the formation of a black hole by collapsing matter.

The problem of Hawking radiation and back reaction of the metric is analyzed to leading order in a 1N expansion, where N is the number of matter fields. The results suggest that the collapsing matter radiates away all of its energy before an event horizon has a chance to form, and black holes thereby disappear from the quantum- mechanical spectrum. It is argued that the matter asymptotically approaches a zero-energy “bound state” which can carry global quantum numbers and that a unitary S matrix including such states should exist. Black holes in higher dimensional space-times Black hole solutions to Einstein’s equations are examined in asymptotically flat N + 1 dimensional space-times.

First generalizations of Schwarzschild and Reissner- Nordstrøm solutions are examined in a discussion of static black holes in N + 1 dimensions. Then a new family of solutions is found which describe spinning black holes in higher dimensional space-times. In many respects these new solutions are similar to the familiar Kerr and Schwarzschild metrics which are recovered for N = 3. One exceptional case though is that for N ≥ 5, black holes with a fixed mass may have arbitrarily large angular momentum.

PHYSICS OF BLACK HOLES

Black Holes and the Second Law

Black-hole physics seems to provide at least two ways in which the second law of thermodynamics may be transcended or violated:

a) Let an observer drop or lower a package of entropy into a black hole; the entropy of the exterior world decreases. Furthermore, from an exterior observer’s point of view a black hole in equilibrium has only three degrees of freedom: mass, charge and angular momentum. Thus, once the black hole has settled down to equilibrium, there is no way for the observer to determine its interior entropy. Therefore, he cannot exclude the possibility that the total entropy of the universe may have decreased in the process.

It is in this sense that the second law appears to be transcended. b) A method for violating the second law has been proposed by GEROCH: By means of a string one slowly lowers a body of rest mass m and nonzero temperature toward a Sehwarzschild black hole of mass M. By the time the body nears the horizon, its energy as measured from infinity, E=m(1−2M/r)12E=m(1−2M/r)12, is nearly zero; the body has already done work m on the agent which lowers the string. At this point the body is allowed to radiate into the black hole until its rest mass is m − Δm. Finally, by expending work m − Δm, one hauls the body back up

##### Project Utilisation of sludge gas for power generation through aero gas turbines

Introduction: Sludge gas from municipal sewage treatment plants is a valuable by-product, containing a high proportion of methane (CH4, 53 to 68 %), which has a calorific value in the range of 19-17 to 24.53 MJ/Nm 3. Since the gas is not easily transportable, it is convenient to utilise it in the vicinity of the sewage treatment plants, generally located at the outskirts of towns and cities.

One way to utilise this renewable energy source is to use it as fuel for internal combustion engines for mechanical or electrical power generation. In the context of the present acute shortage of electrical power in certain areas, such a scheme would certainly be helpful, particularly for standby power generation for peak demand times and for supplying industries located in the vicinity of the treatment plants. While the use of reciprocating gas engines for operation on sewage gas is well known, the present project uses gas turbines, the main advantage of which is that the capital cost would be considerably lower as compared to reciprocating engines, particularly if the turbines are derived from aero-engine applications, after their normal flying duty is completed. Such engines are available at a nominal cost within the country and can be modified to operate on gas.

The other advantages of a gas turbine system are the ease of installation (Ie light weight, low requirement of cooling water), modular maintenance, quick starting and reliable operation. They also have a high temperature exhaust which can be utilised for process heating, thereby increasing the overall thermal efficiency of the system. These engines are in running condition but not certified for aircraft use.

They represent a potential of about 250 MW of generating capacity, which can be harnessed in the manner described and thus save the country over Rs. 100 crores. It may be mentioned that the Dart engine is manufactured indigenously by Hindustan Aeronautics Limited (HAL). Further, there are plans for indigenous development and manufacture of an industrial gas turbine operating on a coal-based fuel. Such an engine could be easily adapted to work on sludge gas also, and because of its proposed advanced design features, the overall efficiency will be pretty high. Thus, a continuous supply of gas turbines will be available in the country for operation on sludge gas.

These engines could also be operated in dual fuel mode (ie, Diesel + sludge gas or kerosene + sludge gas), to meet any operational requirements. A certain amount of R&D work is involved in converting such engines to operate successfully on sludge gas.

Sludge gas production: Sludge gas is a product of anaerobic fermentation of organic matter present in sewage. In a treatment plant the concentrated sewage sludge is placed in large closed chambers called digestors, for periods up to 4 weeks. During this time fermentation of the sludge takes place due to the action of naturally occurring methanogenic bacteria, which results in the formation of a gas rich in CH 4 and also containing carbon dioxide (CO2), nitrogen (N2) and a trace of hydrogen sulphide (H2S). At the end of the digestion process, the slurry is stabilised (ie rendered pathogeni cally harmless) and can be dried to yield a valuable fertiliser. An important practical consideration for gas availability at a sewage plant is the problem of gas leakage through hairline cracks invariably present in digestor domes.

Repair of cracked domes presents many problems and a complete solution is yet to be found. One method of overcoming the problem is to devise an evacuation system which continually sucks off the generated gas, which is then stored in a gas holder, thereby reducing the positive pressure differential in the digestors and hence the leakage. The practicality of such a system was first demonstrated by Pai et al (1978) which gave an encouraging turn to an otherwise hopeless situation. There is of course no reason why similar figures cannot be achieved in India also where the climatic factors are generally favourable for this purpose.

Several treatment plants already exist in the country and more are planned in view of increasing population concentrations at metropolitan cities and consequent pollution problems. It is interesting to estimate the energy availability from this renewable source, given the above variability in the generation rate, in addition to which the variation in CH, content has also to be considered. Based on measurements at a sewage plant in Bangalore, a range from 53-4 to 68.3% can be taken as representative of this. With these figures the rage of energy availability per million of population served by the plant can be estimated (table 1). The thermal power feasible is in the range 2-10 MW per million population

Modifications to aero-engine : The acre gas turbine engine is primarily designed for operation on a liquid fuel such as kerosene (Aircraft Turbine Fuel, ATF). In order to operate the engine on a gaseous fuel such as sludge gas, changes have to be made in the fuel injection and control system. Further, for operation on ground, certain sub-systems such as the oil cooler and the governor have to be modified. The R&D efforts in the present project with respect to a Rolls Royce “Dart” turbo prop engine are briefly described .

(1) Development of gas injector: In the “Dart” engine, the fuel (kerosene) is injected into each of the seven combustion chambers through an atomizer, which sprays the fuel in small droplets in the form of a hollow cone. Figure 1 shows a schematic view of a combustion chamber. The fuel spray is introduced downstream of a swirler which imparts a strong swirl to a portion of the combustion air and creates a region of recirculating flow which helps in stabilising the flame in the primary combustion zone.

The objective of the present development was to devise a suitable injector nozzle for sludge gas which could be retrofitted with minimum changes to the combustion and ignition systems. The limitations were mainly that the injector should be introducible into the existing swirler hub. Since the carlorific value of sludge gas is about half that of kerosene (on a mass basis), it follows that for the same thermal input, the mass flow is twice the value. Further since the density of gas is about 2 orders of magnitude less than that of the liquid, it is necessary to use as large a pipe as possible to keep down the pressure losses.

In order to test various gas injectors, a combustion test rig was set up at the Koramangala & Chellaghala (K & C) valley sewage treatment plant. Here one of the combustion chambers of the Dart engine was set up with an independent supply of air and fuel (sludge gas) at essentially atmospheric pressure conditions.

The basis of such testing is that the gas velocities through the combustor are kept at values corresponding to engine conditions. The performance of any injector which works well at atmospheric pressure conditions would be better under engine conditions where the inlet pressure and temperatures are higher. Several injector configurations were fabricated and tested in this rig. These included injectors with multiple radial holes, a single axial hole and a variable radial slit injector

.

The last-mentioned injector injects the gas in the form of a radial fan jet. The slit gap could be adjusted prior to insertion of the fuel gun into the chamber. The combustion chamber exit was provided with an array of 8 chromelalumel thermocouples so that the temperature distribution at the exit could be determined. The array could be rotated about the combustor axis, to obtain additional data points. The combustor was fitted with the original igniter spark plug.

The injector geometry had an important influence on the combustion characteristics, from the view of obtaining easy ignition, stable combustion and good temperature distribution at the combustor exit. A desirable temperature distribution at the exit is such as to result in the long life of the turbine. The area -averaged temperature traverse quality factor (TTQF), defined as (Tpeak-Taverage)/(delta(Tcombustor)) is a measure usually employed to characterise this feature; a low value being preferable. Amongst the injectors tested the radial-slit was found effective in obtaining good ignition and temperature traverse quality. The slit-width was found to influence the temperature quality factor quite significantly . Subsequently, gas injectors based on this design were fabricated and installed on the engine. A manifolding system was developed to ensure equal supply of gas to each of the seven combustors.

(2)Development of dual fuel injector: The gas injector was further modified to permit operation in a dual fuel mode, ie gas and kerosene. This injector was initially developed in the combustion lab as an air-blast atomizer, and subsequently tested on the engine in single and dual fuel operation.

(3)Accessories and instrumentation: Other modifications to the engine included the development of a digital RPM indicator, a water-cooled oil cooler and high energy ignition units. The digital RPM indicator, apart from indicating engine speed, functione d as an overspeed trip to shut off the sludge gas flow through a pneumatic system in case of turbine speed exceeding a present value. The oil cooler was modified for operation with water as coolant, since for stationary application, the air flow is inadequat e. For starting of the engine, two high energy ignition units operating on 220 V AC were developed in the pilot plant of the laboratory. Other systems developed for operation of the engine were the starting system based on lead acid battery bank, LP fuel feed system for Am, mechanical linkage system for operation of throttle, trimmer, hp cock, speed governor and gas valves, etc.

The instrumentation included panel instruments for indicating major engine variables such as RPM, compressor pressure, jet pipe temperature, torquemeter pressure, oil temperature etc. (4)Demonstration plant: A demonstration plant to investigate the operation of a Rolls Royce Dart turbo-prop engine on sludge gas has been set up at the K & C valley sewage treatment plant of the Bangalore Water Supply and Sewerage Board (BWSSB). This treatment plant has a capacity of 168 million litres per day and provides primary sewage treatment, namely sedimentation followed by digestion of the sludge.

When this project was conceived in 1976, the treatment plant had no facilities for gas storage and the availability of the gas was negligible. Investigations indicated that though gas generation was present, most of the gas was leaking away through numerous cracks in the digestor domes. A pilot gas holder of 28 m 3 was set up and a blower installed to extract the gas from the digestor and fill the gas holder. With this system it was possible to minimise the overpressure in the digestor and hence the leakage. It was possible to collect substantial quantities of gas and the proposal to set up a demonstration plant was taken up.

The layout of the demonstration plant is shown in figure 3 and a general view in figure 4. It consists of a gas collection and holder system, a gas conditioning and compression system, a gas turbine engine and an operating system. The gas collection system consists of a gas blower unit 1-5 kW (2 HP) which extracts the gas from any or all of the four digestors and transfers it to the gas holder. The gas holder is of the conventional moving bell type with a capacity of 2266 m 3 (figure 5). It stores the gas at a pressure of about 90 mm of water column.

The gas conditioning system is a filter filled with material for absorbing hydrogen sulphide. Initially steel turnings are being used for this purpose. The gas compression system comprises a 2-stage sliding vane rotary compressor driven by a 90 kW increased-safety motor, an inter-cooler, oil separators, after- cooler and a cyclone. The gas turbine engine is as discussed above and coupled to a variable- pitch propeller for absorbing the power developed. In the next phase, it is proposed to replace the propeller with a generator for electrical power generation. A gear box to match the propeller speed (1200 rpm) to the generator speed (1500 rpm) would also be required.

, (5)Engine operation and performance: The engine was initially operated on its normal fuel and with the original injectors, to establish the functioning of the various systems. Thereafter, one of the seven combustors was fitted with the gas injector described in §3″1 above, with the remaining ones retaining the liquid fuel injectors. The engine was operated in this mode to establish satisfactory ignition and combustion of the sludge gas within the engine. Subsequently, all the seven combustors were fitted with gas injectors and operation with sludge gas alone was attempted. For controlling the start-up of the engine, a by-pass was provided for the gas after the gas compressor, so that it flows back to the gas holder.

The gas flow was also controlled by means of a gate valve upstream of the compressor inlet. It was found that the ignition, acceleration and running of the engine were smooth and easy even when operating purely on sludge gas. The running time was initially limited to a few minutes owing to the small size of the pilot gas holder. The engine has been operated in the dual mode to estimate its performance. The shaft horsepower is estimated from the torque pressure indicator, which is related to the engine torque through a calibration curve.

To ascertain a suitable operating point for ground running, the engine has been operated at several speeds in its recommended cruise range (13,800 to 14,000 RPM). Figure 6 shows the engine performance when operating with Art alone as well as in the dual fuel mode, at a speed of 14,200 RVM. Due to limitations in the gas flow rate of the installed gas compressor, the engine cannot at present be loaded fully when running on gas alone. Hence liquid fuel upto about 27 ~o (in heat value) is injected to obtain sufficient loading in these tests. (6)Techno-economic aspects: In order to make even a tentative estimate of the techno-economics of gas turbine systems operating on sludge gas, it is important to recognize the large variability in the processes concerned. These relate mainly to the generation of the sludge gas and the engine performance parameters.

Thus,two comparative evaluations are carried out: the first one (evaluation I) considers the lower and upper practical limits for gas generation and gas turbine efficiencies in order to get an idea of the range of power generation potential and costs; the second one (evaluation II), considers various engine and system options for an average gas generation situation. This evah?ation helps in placing the various options in perspective and brings out the influence of sludge gas pricing policy on the overall economics.

Comparison is made with a reciprocating engine system operating on diesel or sludge gas. 6.1 Evaluation 1: The electrical energy that can be generated depends on the efficiency and ratings of the gas turbines available. In the present context of using available aero-derivative engines, it is pertinent to examine the Rolls Royce Dart series 6 engines (which power Viscount and Fokker F-27 aircraft), the Dart 7- series which power the AVRO 748 aircraft and the AI-20 Series-A engines which are surplus with IAF. These engines will be operated at derated conditions in order to obtain a longer time between overhauls.

The extent of derating will have to be obtained by conducting trials on demonstration plants. Section 3 of table 1 indicates the range of efficiencies which may be expected and the corresponding electrical outputs. The worst case corresponds to the Dart 6 operating with lean gas which gives an overall efficiency of just under 14%. The AI-20 engine operating with rich gas will give nearly 7 times this output at a system efficiency of around 20% .

6.2 Evaluation 2: It is well known that the efficiency of simple cycle gas turbines is generally lower than that of reciprocating engines which have higher compression ratios. One technique to improve the efficiency of the gas turbine is to incorporate a heat exchanger between the turbine exhaust and the compressor outlet. Significant improvement in efficiency of the order of 50% can be achieved with an additional heat exchanger and engine modifications. In the present evaluation the effects of attaching a heat exchanger, with an effective value of 0.8, to the engine system are considered.

Another important factor considered is the pricing of the sludge gas which will naturally influence the final economics. Three possibilities are considered, viz: —-sludge gas is supplied free of charge; — gas is charged equivalent to coal on a heating value basis, say Rs. 0-23/Nm^3; –gas is charged equivalent to Diesel oil on a heating value basis, say Rs. 2.21/Nm^3 7. Concluding remarks: The tests with the demonstration plant set-up have indicated the basic practicability of the proposed system, in respect of engine modifications, operation and performance.

Of course, further testing to demonstrate the endurance of the engine is still required. The indications of the combustor tests as well as the fortuitously low sulphur content of the gas (as a result of absorption in the gas holder), suggest that long life between overhauls should be possible. Thus ,there is every reason to pursue the proposal further by setting up actual generating plants wherever possible. Also , every effort must be made to set up and optimise sewage treatment plants wherever necessary, in order to reduce pollution and to utilise the by-products such as sludge gas and fertilisers to the maximum extent possible. References : Trevelyan W E 1975 Tropical Science 17:193-209. Pal B R, Abbey D K 1978 Bio-gas production from sewage:

A preliminarystudy, NAL-TM-PR-000/I-78 Barber N R 1977 Industrial Gas: 20-21

##### Feelings

Credits KHUSHI JAIN

An individual has a bunch of different emotions inside him, sometimes we can express to other person n sometimes we cannot.. all of us have feelings which are good n bad.. many of us even feel to run from our mistakes, from people, so that we don’t need to face our lives, our mistakes, and sometimes we really need a break from everything that’s going in n around us, and sometimes even I feel that and I feel it’s ok to take a break to have fun, to forget about everything that is going on in n around u n its okie to have fun, n explore or u may even feel to just lay in our bed for a day to just let all the feelings n emotions go aways n it’s fine.

Sometimes we all try to fight about how we feel, n most of the time we r just running from ourselves, in order to not feel the pain anymore, but in the end, we all have to face the reality

So its okie to understand your feelings and give importance to them. feelings are the reason for a human being to be alive and to feel all the emotions inside him, happy, joy, sad, anger, rage etc.

we should always be happy and accept and understand what going on in our life…

I guess happiness is the best gift you could give to yourself and to others, spreading happiness make you feel happy and satisfied with your life.

Life is an amazing gift that anybody could get sometimes we get depressed and we feel like we should not even exist and I guess that’s the worst feeling anybody could get in their life…

it’s all about what an individual thinks and believes, in spite of thinking this we could even think that we are so blessed with such a beautiful life and can be happy and spread happiness…

In our life sometimes we have that one special person who is known as the love of our life.. n we care a lot about that person and we feel that he /she is everything n we do have strong feelings about them that they gonna stay with us n not gonna hurt us forever and when all this happens we feel really great…

Life is not at all easy but people who are with us make us feel that is not so much miserable, they help us know the value of life and humanity and the value of love…

love is something that makes us feel so good about ourselves n about everybody else… so I think feelings are one of the most important parts of our life about our existence and if we get a chance to express our feelings to someone we should and on the other hand side we should always choose to understand one’s feelings and should stop hurting it..

because they say that sensitive people have a lot of feelings n emotions inside them and we should never hurt one’s feelings. so in order to stay happy n enjoy our life, we should give importance to our feelings as well as the other person’s feelings as well…

##### Dopamine levels : Are we in control Or Are we being controlled?

MaterialismMaterialistic love, Oh! How void and incomplete a thought that a man can possess! The world is so much more than the world that we perceive as material, so much more.

And how wonderful a role Dopamine plays in making people fall into the spider’s traps of ignorance as if nature knows only the values of pleasure and pain. Pleasure and pain, the natural equivalents of biological positive and negative, seem to play an intrinsic fundamental role in nature’s genetic language.

Now that we think of it, it is perfectly natural and humane to run behind pleasurable things may it be material or not, if it pleases the body then it’s very nature of the body to want more and more of it. So much that our demand keeps on increasing, driving us deeper into the realm of madness. But then, are we beasts to let such meagre materialistic things take control of our life? Are we really driving our intellectual property straight into the wall of blissful ignorance ? Dopamine detox – Coming back to the ground An elegant solution to many questions is ‘Time’ itself.

Just as water plays the role of universal solvent in the science of chemistry, Time plays the role of a moderator, a keeper of tranquil harmony, in the algebra of pains and pleasures, and turmoil of emotions.

Dopamine Detox, a rather fancy word for a simple process, involves nothing but abstaining from all the materialistic pleasures, for a specific amount of time, that seemed to have trapped oneself.

The logical explanation behind this detox is pretty trivial, spending sufficient time away from one’s desirable things gets our dopamine levels back to normal.

It can include various things according to one’s lifestyle, for example – keeping away from social media for a week, abstaining from junk food for a month, resisting alcohol, drugs, etc.

By now you must have picked up the underlying idea, we are trying to take things slowly so that we learn to appreciate details of life and the world, by keeping ourselves in control. Go ahead then! Give it a try, for you will only understand its importance when you get your mind free from all sticky external influence and its natural pure state.

##### Are Apples Really red

A simple way to answer this question would be to say that, “ Apples are red because I see them red.” But wouldn’t that be a really naïve way to answer such a profound question as that, not likely to quench any educated human’s curiosity. Hence, our little aim will be to stride progressively in the direction of undermining our incomplete foundation of colour theory and rebuild it with a tinge of universal wisdom.

To begin with we really need understand the question – “ What is Red? “. A layman’s definition of the colour red would be – “ Red is the colour of an Apple “ and why shouldn’t it be. Right from the early sweet days of our kindergarten years we have been hammered by this impeccable statement to the point that we never really think of red’s independent existence or eternal origin. However the Oxford dictionary defines red as “A colour at the end of the spectrum next to orange and opposite violet..”. Let’s stick to this definition for the sake of moving on, but it still doesn’t help us in answering our questions.

In one’s high-school years one learns that a certain type of waves called as Electromagnetic waves are responsible for the production of sense of colour. In the case of red, an electromagnetic wave having a wavelength of about 700nm hits some of the cone cells of our retina and curiously, the brain makes up a minute coloured spot at that point. And we have been told to perceive this colour as ‘Red’. Doesn’t this raise a vey fundamental question – Does the colour red really exists? Or is it just an imagination of our developed brain? And not just red, this is a question that seemingly creeps on the entire spectrum of colours, radically making us think of our once very much strong notions.

Biological reason behind an Apple’s red colour :Colours in plants are the result of pigments which by support wrap the plant part in a discrete but seemingly continuous texture of their protein bound bodies. These little stacked up micro-organs have a crucial role of harvesting energy and help about in making redox reactions happen. The important part for us here is the ‘Harvesting of energy’, during this process the plant pigment absorbs only a certain part or a range of wavelengths from the incoming solar light while the remainder is reflected. It is this reflected light that happens to fall on our delicate retinas thus producing a complete colour picture.

The red colour is derived from the pigments called as anthocyanins, these develop and immask the fruit as it grows. The same phenomenon can be witnessed in cherries, raspberries, cranberries and other red fruits. Having a variety of medicinal values, these anthocyanins serve a small purpose of ‘White Knight’ for the plants by absorbing the excessive light flux which has a potential to damage the chlorophylls. But, Behold! There’s something more that these White knights unknowingly do, their rich colour which we, humans and some animals, perceive as ‘Red’, is a colour of caution & attraction, It draws over a swarming number of pollinating insects and arboreal animals towards it. The only reason behind all this being the colour ‘Red’. Isn’t it beautiful how a small natural phenomenon can depict a magnanimous aspect of the world? The Fruity results of Evolution:In 1859, Charles Darwin published his first formulated book “ On The Origin Of Species ”, a text so controversial and radical that it shaped the human mindset so drastically over the next decades. The key ‘Natural Selection’ remains the central crux idea of the whole wide web of biological diversity. You might be wondering why did we suddenly step into this big pool straight from the subject of colours and apples, but there’s an elementary reason behind it, we are diving a bit deeper so as to understand why the nature picked the colour ‘red’ for her baby ‘apple’.Evolution brings about a colossal change but it also costs an eon. All the fundamental characteristic questions such as, ‘Why does a Cheetah has spots ?’ or ‘ Why do lions hunt ’ etc, always have an evolutionary answer to them that clearly and logically gets rid of our small creeping doubts and presents the world in its uttermost scientific state.In case of our apple study, we will be looking at it through two different points of views one being the ‘modern synthesis’ while other being the ‘Lamarckism’. Before starting to give a brief description of what these two are, I would like you to note that Lamarckism is not widely accepted today and is an almost discarded theory, yet we will be discussing it here because it provides precious ideas and insights of evolutionary theory.

Lamarckism:Lamarckism, an inaccurately named notion after the French biologist Jean Lamarck, is a hypothetical idea that says that an organism passes its physical characteristics over to its offspring which it acquires over its lifetime. One of the fundamental laws of this theory dictates that a new organ or a feature is obtained in an organism once it feels the arising need of it and passes down this information to its offspring biologically. And in our analysis, this shall be the only needed point from Lamarckism.Now, if we were to say that – suppose Apples weren’t red at the beginning but only slightly reddish due to the availability of anthocyanins in smaller amounts, then Lamarckism provides a pretty explanation to this – The reddish apples biologically gathered the info that Reddish Apples were more favoured by the pollinators, and hence this characteristic being passed down to the next generations, the apples grew redder and redder until they were finally red.But this explanation seems to be supported by some rather vague assumptions that the apples had indeed some anthocyanin in them and were not red but of some other dull colour. Hence, one would say that this isn’t quite satisfactory and it still leaves some potholes yet to be filled. No worries! We only discussed this part so as to ready your mind on how really an evolutionary explanation works. Thus far, this isn’t really a proper explanation since we used the now discarded, Lamarckism, We shall proceed with the theory of ‘Modern Synthesis’.

##### The School of Athens

WRITTEN BY ABHIRAJ MENDAGE CS NITK

Raphaels Frensco

It is curious to note their body movements, Plato is pointing up towards the sky, symbolising his theory of Idealism, while Aristotle is turning his Palm down to the ground portraying Realism.

Plato’s Idealism VS Aristotle’s Realism

Originating from Pythagorean Philosophy, Plato’s Idealistic views bring in focus that ideas are what defines the real world, the true world cannot be represented through physical forms. For example, taking the common example of a tree, we see a tree in its physical form, with a bunch of markings and irregularities in its natural twigs and branches but Plato argued the idea of Tree gave the thing its true existence and not the physical form we see. Abstraction is the firm foundational unit while materialistic reality is only a crude reflection of the eternal truth subject to change unlike ideas. Since the old Athenian times, where Plato’s Ideas were taught in his school called ‘Academy’, Platonist Idealism has changed a lot through these periods. A detailed reading of the evolution of Idealism can be found here: https://plato.stanford.edu/entries/idealism/ Aristotle, student of Plato the Great, broke away from his mentor’s idealistic philosophy and built the foundation of a new philosophy known as Realism, with a pillar of scientific method supporting it. He believed that the existence of reality is independent of the mind, it all narrows down to perception. Realism focuses on the perception of materials through our senses rather than dwelling on abstract ideas of mind, this marks the key contrast between Idealism and Realism.

Plato’s Allegory of the Cave

Plato finally concludes, the prisoners are so ignorant that they would murder not only the person but even the idea which tries to drag them away from their cave, thus portraying the place of philosophical and scientific reformer in a thickened ordinary world.

##### Prime number secrets revealed

Deepan K S ( 1st year , NITK

Among the whole numbers , the numbers which always fascinate me are the prime numbers ! !A prime number is divisible only by itself and 1 .Suppose I consider a sequence of even numbers { 0 , 2 , 4 , 6 , …. } . General term of the sequence of even numbers is 2n , where n = 0 , 1 , 2 , 3 ….Similarly, for a sequence of odd numbers { 1 , 3 , 5 , 7 , …. } , the general term would be 2n+1 , n = 0 , 1 , 2 , 3 , …But if I consider a sequence of prime numbers { 2 , 3 , 5 , 7 , 11 , ….} , till now we haven’t found out a way to get the general term of this sequence of prime numbers !!The ancient Greek mathematician Euclid proved that there exists an infinite number of prime numbers using basic calculus .There are no direct formula or a fast method currently available to check whether a number is a prime number or not . There are algorithms to check whether the number is prime or not , but they are time consuming. Prime Number play a huge role in the assymetric encryption of public-private key 🔑 using *RSA* ( Rivest-Shamir-Adleman algorithm ) . It involves factorization of a number into two prime numbers .The larger the two prime numbers, the factorization becomes more difficult and slower . This method is commonly used in encrypting ( public – private key ) the messages .Prime numbers are the one of the most amazing things ! I have come across in the world of maths, which we have least understood. Exploring it further will make a huge difference in the future of science and technology ! – Deepan K S ( 1st year , NITK )

##### Indian folk dances

:Kathak:-Kathak is one of the major forms of Indian classical dance.The term kathak is derived from a Sankrit word Katha means story and Kathaka means “he who tells a story.Kathak is performed to a primary percussion instrument (usually a Tabla) or orally recited beats.•Both men and women wear ‘Ghunguroos’ or Ankle- bells, as they are the prerequisite to this dance form.•There are different styles of Kathak called the Gharanas (which literally means the house of the Guru). Lucknow Gharana (In the present day, Pt. Birju Maharaj ji is the torchbearer of this Gharana), Jaipur Gharana, Benares Gharana .

Bharatanatyam:-It is one of the most popular Indian dance form which took birth in Tamil Nadu.Due to its wide range of movements and postures and the balanced melange of the rhythmic and mimetic aspects lends itself well to experimental and fusion choreographyBharatanatyam encompasses a wide variety of skills, it is a dance form that requires the dancer to have experience of theatre, music, literature and poetry.There are two main elements of bharatanatyam which are Nritta and Nritya:-•Nritta is pure dance, it is creating complex movements and patterns to rhythms. It does not have a focus on meaning but it expresses the joyous energy and beauty experienced by the dancer. •Nritya is a combination of rhythm and expression. The dancer would perform to a poem or song by using subtle facial expressions and hand gestures

Kuchipudi :-It is among the top classical dance forms of India and is indigenous to Andhra Pradesh, the south Indian state of India.•It is different from other dance forms as it includes singing as well as part of its native dance form.•The female dancer categorically wears a pleated saree that has fan like pleats attached in the front which open beautifully as the dance unfolds. The male dancer usually wears a dhoti.•Indrani Bajpai and Yagini Krishnamurthy are the two main names behind popularising Kuchipudi and expanding it on an international platform