"REALISED" an Article

One day, some "x" was so angry, that he left home, swearing not to return, till I became a big guy. Parents, who can't even buy me a Bike, have no rights to dream to make him an Engineer. In his fit of anger, he didn't even realise that I was wearing my father's Shoes. he even stole his wallet, which had some papers, torn as well, which his mother won't seen...
While, he was rushing on foot towards the bus station, he realised some prickly pain in his foot. he also felt dampness inside the shoe. That is when he realised the shoe had a hole underneath.
There were no buses around. Not knowing what to do, he started to look in his Dad's wallet. he found a loan receipt of Rs. 40,000, which he taken from his office. A laptop bill (he had bought for him). To his utter shock, also found a letter from his manager to wear a neat looking shoes, henceforth to the office. he remembered his mother pestering him to buy a pair of new shoes, but he would convince her that his shoes would last another six months atleast.
Also, found an old scooter to a new bike, Exchange offer letter in his wallet.
he instantly remembered, that when he left home, his Dad's scooter was not there.
he started feeling weak in his legs, and felt like weeping uncontrollably!. he ran back home with his foot paining, only to find his Dad nor the scooter there. he found him at the exchange offer place.
Looking at his Dad, his grief engulfed him. he hugged him tightly and started crying loudly, said "Dad I don't need the Bike".
That is when he realised, the pain, hardship our parents go through, and the unconditional love that they give us. We should only look to seek our needs and not our unrealistic wants.
Ridiculing parents when they are alive, and longing for them when they are not around, has no meaning..
Kindly tell this story to your children to help them identify and develop human values in them........unknown

Note : non technical but makes you realize some things in you life

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Evolution in House Cleaning

We all want want to see our houses clean and tidy. Are we doing it with a involvement?  I would surely say NO as we always search for others to do that job done. The reason behind that may be fatigue, boredom or any other thing. Many ideas popped in electronics to supplement this opportunity. By which many companies have grown into giants by utilizing them in a smart way. The vacuum cleaner was invented as a product to ease the cleaning job. As it needed a human involvement and required human time which is the most valuable thing in the whole world, companies such as iRobot, iLIFE, LG,bObsweep and many others have developed products to ease the life.
To eradicate the human involvement vacuum robots were introduced which started working on their own at fascinating prices. These devices were programmed with various programs named Robonavi, Home Guard etc... for specific purposes such as detecting obstacles, Auto Charging, Auto Movement, Schedule working, Manual control option etc..They are designed to be controlled over smartphones, remote control. They even do use various types of side brushes,long brushes at the bottom also. They have attractive body design enabling it to move under the furniture's without the need to lift them. Most of them have an attractive LCD screen on the top displaying its charge status and the time sometimes.

Recently in the Consumer Electronics Show in  Las Vegas on 6-9 January, the product LG HOM-BOT Turbo+ robot vacuum was introduced. A wireless security camera is installed with a Triple eye camera sensors to detect where it has already cleaned. This product is built on Augmented Reality (AR) technology with a smart feature known as Home Joy. The movement is controlled by Robonavi software. The Home Guard smart feature is also installed in this device to send pictures to the user for extra security and peace of mind. This has a 80 V Lithium-ion battery that is good for about 40 minutes.

With these speed of advancement in the electronics industry, there is no doubt that the type of living which we are living will be lost as our parents boast that, in their age there were no Cellphones. As elders say "Change is the only thing which is eternal"

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WHY ELECTRICAL ENGINEERS WERE JOBLESS????

Hello,I thank each and every reader of the following article.

To get started, i need to begin with the students life from final year of  B.Tech. Because that was the decisive time when every student have his/her own ideas about his/her career. Further, we discuss only about how the life of an electrical engineering student turns.

                                                                         

                                                                         Apart from the students of IIT's and NIT'S, all other students from private engineering colleges and universities face quite a common problem, that is lack of placements in their respective colleges/universities. As we have good number of software companies, they recruit "n" number of students, but the thing to be notified is 95 percent of the companies recruit students of electrical department for the posts of Business Process Outsourcing       (BPO), Tele-Marketing & Transactions risk investigation, having no alternative prospects more than 75 percent of the people migrate to software. We are now left with remaining 25% of the students, reasons may be many either due to lack of interest in software or their love towards their field of study they step out of the college with great percentage, but less knowledge, with worth full study but useless degree, less confidence but great ambitions.  

                                                                                 

                                                                                In fact, four ways for career building will revolve in minds of these students, they are MS in US, Government job, job in private sector industries and Entrepreneurship. Among these 25 percent of the students more than 10%  get motivated by their friends advisory and by the US dollar dreams and fly up, driving there parents to face economical risk factor. However, now a days to secure a government job is quite a difficult task as many barriers like reservations, illegal job Mafia restricts you to get through a govt. job. 5 % of the students still with a little hope keep their perennial efforts to crack them.

                                                                                    

                                                                                  However, from the remaining ten percent of the students 3 to 4 % of the students get settled by taking up the charge to look after their family business. The remaining 6 to 7 % of the students on contemplating all these consequences, they try to get through the private industries, but the fact is 98 percent of the private jobs were filled up by references. And moreover life of students who migrated to US  for pursuing masters is also a question with no answer.  Can we blame anyone for the following consequences?, instead throwing blame on present education system, on government and on the situations we face, feeling responsible of our own career might bring a change.

                                                                  Students are found to be poor, poor in knowledge, poor in intellectuality, poor in self-decision making, The worst thing is to serve them because,

TELL THEM IT'S A SMALL INVESTMENT, THEY SAY CAN'T EARN MUCH.

TELL THEM TO COME IN BIG , THEY'LL SAY NO MONEY.

TELL THEM TRY NEW THINGS, THEY'LL SAY NO EXPERIENCE.

TELL THEM IT'S TRADITIONAL BUSINESS, THEY'LL SAY HARD TO DO.

TELL THEM IT'S A NEW BUSINESS MODEL, THEY'LL SAY IT'S MLM.

TELL THEM TO RUN A SHOP, THEY'LL SAY NO FREEDOM.

TELL THEM TO RUN A NEW BUSINESS, THEY'LL SAY NO EXPERTISE.

                                                                                    

                                                                          In fact they have some things in common they are THEY LOVE TO ASK GOOGLE,  LISTEN TO FRIENDS WHO ARE AS HOPELESS AS THEM, THEY THINK MORE THAN AN UNIVERSITY PROFESSOR AND DO LESS THAN A BLIND MAN, when we ask them, what can they do, they won't be able to answer.

Though i too belong to these sector of students,but started  trying to put my ideas in to action to achieve something that i dream to. So my conclusion is instead being jobless,establish yourself to survive, and to succeed. Create an opportunity instead waiting for the one.

GO, GIVE, LIVE with a motto 

"INSTEAD OF JUST THINKING ABOUT IT, WHY NOT DO SOMETHING ABOUT IT"

do not waste your life just by waiting......................,

 NOTE: Inspiration to write this article "JACK MA" Founder of ALIBABA.                                                                      

                                                                         

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Lightning strikes during flight (solution by Lufthansa Technik)

Lightning strikes during flight

No danger despite high voltage

  

In commercial aviation adverse weather conditions mostly happen underneath cruising altitudes. But even on lower flight levels they are rarely a big issue because every modern commercial airliner is equipped with weather radar. These systems help the flight crew to identify storm fronts in the flight path of the air plane and give hints to circle around the bad weather. But sometimes an air plane might have to fly right through adverse weather regions because there is not enough time to avoid the detected hailstorms or thunderstorms. The latter are not uncommon in this case to scare the passengers with a bright flash of light and loud bang, mostly followed directly by an announcement from the cockpit: "Lightning strike–. These incidents are very rare in modern air travel, even frequent flyers only have a very low chance to witness a lightning strike on one of their flights. A commercial aircraft however is struck several times during its whole service life.

In such a case, the airplane acts like a lightning rod. Its metal structure provides the lowest resistance for the electrical discharge on its way between the clouds and the ground. It is not uncommon that the airplane is thereby struck by a complete series of discharges, mostly between three and five, in exceptional cases up to 25. Since an airplane in flight has no form of grounding, the lightning first enters the structure and leaves it again a split second later. The principle behind this occurrence is known by most people from physics lessons in school. The airframe acts as a so called "Faraday cage–. Like an automobile body the aluminium structure, when struck by a lightning, passes the electric energy around the interior and keeps the passengers safe. The crucial technical equipment is thereby also kept safe from the high voltage and the aircraft can, in most cases, proceed normally with its flight. But to play it safe every lightning strike is documented by the cockpit crew and the aircraft is treated with a special inspection routine on its next check. Lightning strike inspections like these are regularly carried out at Lufthansa Technik.

A special lightning strike inspection procedure is manifested in every aircraft's maintenance manual and is usually divided in two stages. Stage one comprises in-depth visual inspections of the entry and emergence points the electrical discharge went through. Scorch marks of the high voltage are quite hard to locate on the painted surface of the aircraft because their diameter is often smaller in size than a pinhead. However, the highly qualified personnel of Lufthansa Technik is very quick to detect the traces of a lightning strike, because from their decades-long experience they know exactly where to take a look at the different aircraft types. The myth that a lightning always strikes at the highest elevation is in the air as false as on the ground. Not the high tailfin is the favourite point of impact, at most aircraft types the lightning enters the airframe at the edge of the cockpit windows or the leading-edge of the wings. The favourite exit points for lightning turned out to be the winglets or the tips of the aircraft's control surfaces. Scorch marks caused by electrical discharge are also often found at the border of rivets and the trailing edge of the wings, where so called "electrostatic dischargers– are mounted. These thin sticks, which normally return the natural electrostatic charge the airplane collects through atmospheric friction, provide one of the easiest exits for lightning energy. Sometimes these parts get even completely burned away by a lightning strike, which sounds dramatic but has no negative effect on the safety of the aircraft. 

• 

  Static dischargers on the wings' trailing edge: frequent exit point for lightning strikes
• 

  A lightning often leaves the airframe in the gaps between single parts
• 

  A lightning can also discharge through the edges of screws or rivets

Lightning strike inspection: a routine business for Lufthansa Technik

Inspecting an aircraft struck by lightning can take up to several hours depending on the aircraft size and visibility. When the personnel of Lufthansa Technik has located the entrance and exit marks of the lightning strike, stage two of the inspection procedure comes into effect. Parts with suspicious scorch marks are now looked at more closely, from the outside as well as from the inside. Burned off static dischargers are replaced with new ones. Rivets affected by lightning damage are examined with methods of non-destructive testing and replaced if necessary. Lightning damages in the airframe, the wings or the empennage normally never occur if these structures are made of aluminium. The use of composite materials like carbon-fibre reinforced plastics (CFRP) however, makes these parts more sensible to lightning strikes. The high temperatures generated by the electrical discharge can boil and melt the resins used in composite materials and hence weaken the structure. Aircraft types currently in development like the Boeing 787 or Airbus A350, who will feature a nearly all-composite fuselage, have therefore to be protected by special mesh of glass or metallic fibres to derive the electric energy from the airframe structure. The radome in the aircrafts nose is harder to protect, because a metallic mesh would cause interference in the weather radar underneath it. To avoid false readings in this systems the radome is protected with narrow metallic "lightning stripes– which are electrically connected to the fuselage structure to ensure a safe conduction. Moving parts like landing gear doors or high lift devices are also cable-connected to the airframe structure for this reason.

The structure of a commercial airplane is hence well protected against lightning strikes, even if the surface is wetted by rain. Much more problematic are water ingressions inside the airframe structure, which can lead to problems with aluminium as well as composite structures. The high energy of a lightning strike can evaporate the water within a split second which causes a sudden expansion that can in some cases damage the structure. But since commercial aircraft are regularly checked for water ingressions because of corrosion protection issues, such a case is highly unlikely. Another component in need of protection is the avionics equipment, comprising all electronic devices of the aircraft. Although its main parts are, like the passengers and the crew, protected by the airframe's Faraday cage, the avionics equipment can as well be affected by a lightning strike, for example through necessary external sources like antennas. All electronic devices on board are therefore protected by an overvoltage arrester and designed as redundant, so that in case of a malfunction a backup system will quickly take over. The protective systems successfully proved to be working: The personnel of Lufthansa Technik have, despite decades of experience, never discovered any damage to avionics components caused by a lightning strike. The safety of a modern commercial airliner is hence normally never be affected by such incidents. But to play it safe and to further ensure the operational safety, Lufthansa Technik always carries out the described inspections prior to the next flight after a lightning strike. 

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Threat to HV research? (HIGH-VOLTAGE EFFECTS AIRCRAFT)

Article from NewScientist Magazine

ELECTROMAGNETIC pulse weapons capable of frying the electronics in civil airliners can be built using information and components available on the net, warn counter terrorism analysts.

All it would take to bring a plane down would be a single but highly energetic microwave radio pulse blasted from a device inside a plane, or on the ground and trained at an aircraft coming in to land.

                                           

Yael Shahar, director of the International Institute for Counter-Terrorism in Herzliya, Israel, and her colleagues have analysed electromagnetic weapons in development or used by military forces worldwide, and have discovered that there is low-cost equipment available online that can act in similar ways. "These will become more of a threat as the electromagnetic weapons technology matures," she says.

For instance, the US and Russian military have developed electromagnetic pulse (EMP) warheads that create a radio-frequency shockwave. The radio pulse creates an electric field of many hundreds of thousands of volts per metre, which induces currents that burn out nearby electrical systems, such as microchips and car electronics.

Speculation persists that such "e-bombs" have been used in the Persian Gulf, and in Kosovo and Afghanistan - but this remains unconfirmed. But much of what the military is doing can be duplicated by others, Shahar says. "Once it is known that aircraft are vulnerable to particular types of disruption, it isn't too much of a leap to build a device that can produce that sort of disruption. And much of this could be built from off-the-shelf components or dual-use technologies."

It isn't much of a leap to build a device that can produce that sort of disruption in aircraft

For example, government labs use high-energy EMP devices to test what would happen to critical electronic systems if a nuclear weapon detonated, generating a vast electromagnetic pulse, says Robert Iannini, founder of Information Unlimited in Amherst, New Hampshire, which sells EMP test systems.

EMPs can be created in a number of ways. A machine called a Marx generator can quickly dump an extremely high charge stored in a bank of capacitors into an antenna, which then releases a highly energetic radio pulse. Devices like this are often used to test power lines for their resistance to lightning strikes. An alternative, known as a flux compression device, uses a small explosive to push an armature through a current-carrying coil that is generating a magnetic field. This compresses the magnetic field, again producing a devastating EMP.

Iannini says his company only sells such devices to legitimate buyers. "The only people that buy these things are qualified researchers at labs like Sandia. They never find their way into the labs of pseudo or amateur scientists," he says. "If we get any unknown overseas purchaser we immediately alert the office of export enforcement at the US Department of Commerce."

But Shahar told delegates at the annual Directed Energy Weapons conference in London last month that security at some labs can be lax, while basic EMP generators can be built from descriptions available online, using components found in devices such as digital cameras. "These are technologically unchallenging to build and most of the information necessary is available," she says.

The increasing use of carbon-fibre reinforced composite in aircraft fuselages is also making them more vulnerable, she says, because composites provide poor shielding against electromagnetic radiation compared with metal. "What is needed is extensive shielding of electronic components and the vast amount of cables running down the length of the aircraft," she says.

Jerome Bruel, an electrical systems expert at the European Aviation Safety Agency in Cologne, Germany, agrees that newer all-composite planes like the Airbus A350 will probably need some means of protecting their cabling from all radio energy sources, including TV transmitters. "They may need a metal mesh surrounding them to absorb interference," he says.

Douglas Beason, a director at the Los Alamos National Laboratory in New Mexico, says it may be straightforward to build a do-it-yourself EMP weapon, but more difficult to make one that can be stowed in an aircraft. "A lot of work would need to go into dramatically decreasing the weight, shrinking the power supply and antenna," he says.

Nevertheless, governments are taking the threat seriously. A spokesperson at the UK Department of Transport said the government is well aware of this security issue and has close links with agencies "able to provide a balanced picture in regards to EMP weapons, and their potential to compromise civilian aircraft".

Its true that information and material are available but well just put your thoughts on it and what you think would be a better way to stop this without stopping researchers.

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A Novel design of Capacitive Transformer

ABSTRACT

The proposed micro transformer is based on polarization in dielectrics. It is a low expensive, small, lightweight, core less, heat less, high efficiency transformer. It has variable output voltages with good current output. It is just like the conventional transformers but the number of windings is less and core is not used. It has only two terminals like diode. The both primary and secondary winding wires are made up of copper and coated by silica dioxide. The area of conductor determines the voltage induction and the dielectric medium determines the current output. Here silica dioxide is used as a dielectric medium because it has good permittivity. In this transformer the electromagnetic field is not created. The novel theory behind it is that wherever an alternating potential presents, a region is developed around it. This phenomenon can be named as Electro Tele Field (ETF). The dipoles are rotated due to the application of alternative voltage. The alternative voltage consists of positive and negative half cycles. During the positive half cycle, dielectric medium is positively polarized, and during the negative half cycle, medium becomes negatively polarized. Hence dipoles get rotated continuously. A continuity tester can detect that field. ETF can flow through conductors and penetrate in insulators. The paper explains the novel effect of alternative voltage on a dielectric medium. The main application is that the emf can be induced from one coil to another coil without electromagnetic field. It is hoped that the micro transformer will make a turning point in transformer usage.

Necessity to work on this project topic : An accident made this innovation. one day i bought a continuity tester in front of the television picture tube, then the tester glows without any electrical contact. this incident makes me to do series of experiments on this process. i named it as Electro Tele Field [ETF]. The word Tele indicates television picture tube because very first time, this field was discovered in front of television picture tube so that the field is named as "tele field". At last i could find the reason behind that. By the application of this new theory, A novel core less micro transformer has made successfully.

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Future of Solar Cells

We have all heard about the solar energy which can be harnessed for free, as it is a natural resource. Yet most of us are not using it in our daily life.
Possible reasons

• Highly expensive
• Needs maintenance
• Not reliable in rainy or cloudy seasons
• Needs a large Installation area
• Mostly delicate to use ( Breakage Possibility)

To solve these issues researches have been pursued all over the world.
In the search for reducing the effect of these issues many Universities have been working. And one of the best idea was to reduce the mass and increase the flexibility of the solar cells. 
Among those trials by the universities, the MIT research center has come up with a Ultrathin, flexible Photovoltaic Cell which solve most of the major issues which we are facing.

These Solar Cells were so thin, flexible. and lightweight that they were introduced by placing them on a Soap Bubble.
The essence of this research is to manufacture a solar cell in which the substrate and the protective coat are made in a single process which skips many other strenuous processes such as the cleaning dust, handling and removing etc..

The Unique credibility of this idea is that " The substrate is grown along with the device"

In the proof of concept experiment  parylene is used as a substrate and the coating. The DBP is used as a light absorbing layer. The resulted layer is 80 microns.  The vapor deposition technique is used for growing the substrate and the protective layer.

Further research is being done with different materials as substrate and encapsulation layers. Even the different solar cell materials are also suggested instead of the organic layers used in the above test.

The size of the Solar cell using Parylene is 2 micrometers thick and has a efficiency equivalent to glass substrate solar cell. This new solar cell can produce 6 Watts per gram i.e, 400 times higher than the silicon based solar module which produces 15 Watt per Kilogram.

The commercially available product may take years, but when released it has more pros due to its "Power to Weight Ratio "These cells can create a major breakthrough as it can be installed on all existing structures without any major change in weight.

This manufacturing process was presented by MIT Professor Vladimir Bulović, research Scientist Annie Wang and Doctoral Student Joel Jean, in the journal Organic Electronics.

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what if our ceiling fan gives us power in return?!!!!

I don't know whether it's possible or not. I recently heard a class about renewable reso

urces and recycling.......After hearing that, i was observing the surroundings for something to recycle & reuse.Now, taking the ceiling fan, the electrical energy is being converted Mechanical energy.So i was thinking that ,whether we can convert this mechanical energy back into Electrical energy and make it a cyclic process. i.e. fixing an electrical winding (just like a rotor in electric motor) in the hook of the fan, and to make a magnet to rotate around this winding with the help of rotating base of the fan.The magnet is fixed to the rotating base, so that it also rotates,from which current is produced.will it work, what's your opinion?

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IMPULSE VOLTAGE GENERATOR

VIDEO LECTURE - 01

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SOLAR SCARE MOSQUITO (HOW TO MAKE IT ?!!)

NOTE: QUITE INNOVATIVE SOLAR PROJECT FOR B.E/B.Tech

I am pretty sure that there will be people who disagree, but mosquitoes are by far the most irritating insects around. Of course this is the opinion of a person who has to only deal with the itchiness for a few days and then forget about the unpleasant experience. But many are not so lucky.

Every year, over a million people are killed by malaria and there is no effective method to tackle this problem. The only solution is to destroy mosquito breeding grounds and curb the problem at source. As mosquitoes breed in stagnant water, I concluded that surface aeration would the best means of eliminating breeding grounds. It would prevent a mosquito from laying eggs as it can lay eggs only if the water surface is completely still. And even if the mosquito does lay eggs, its larvae would suffocate as they need to remain on the water surface to breath. The device would also reduce the larvae’s source of nutrition as aeration hinders the development of algae, anaerobic bacteria and the surface micro layer. So I built a solar-powered device that creates surface turbulence through aeration and thereby prevents mosquito breeding:

Watch the device in action: Solar Scare Mosquito

This device automatically switches on when it comes in contact with water so that it floats up and starts running when flood-water gets collected. It generates air bubbles that can effectively produce ripples up to a radius of 2 meters. The air pump is timer-based and runs at intervals of 10 minutes to increase the life of the device and maintain a balanced water oxygen level. I have also provided an alarm which alerts if the water body dries up or someone tries to remove the device from the water.

The world is spending billions of dollars for developing vaccines for vector-borne diseases like malaria. However, curbing the problem at source is a much direct and effective solution. At less than $10, this device is not only affordable for developing countries like India, but can be easily implemented at large-scale. At present, there is no such sustainable product to reduce mosquito breeding in water bodies.

If this device is improved upon and ubiquitously installed in villages and cities, then I’m sure the world will soon be free from mosquito borne diseases like malaria and Zika.

Do contact me if you are interested in developing this product or would like to have these installed in your community!

Coming Soon Solar Scare Mosquito 2.0.

Step 1: Hypothesis

More than half the world's population is vulnerable to vector-borne diseases. These diseases, namely malaria, largely affect children and poor people and there is no promising solution to eradicate it.

Question: So how can we control malaria using technology?

As mosquitoes transmit malaria and water stagnation is the primary cause of mosquito-breeding, by preventing water stagnation, it should be possible to curb malaria.

Hypothesis: By devising a surface aeration system for small water bodies, it should be possible to control mosquito breeding.

Step 2: Don't stagnate... Research!

The primary reason why mosquito breeding cannot be easily controlled is that all breeding grounds need to be either regularly emptied or regularly treated with insecticides. Regularly emptying surrounding objects is tedious and often not practical. And employing people to regularly treat water bodies with larvicides and fogging is expensive. Therefore potential breeding grounds are not maintained and stagnant water in common elements of a cityscape like birdbaths, rain barrels, water reservoirs, ponds, swamps and sewage lines become vulnerable to mosquito breeding.

On evaluating the ideal conditions for mosquito breeding, I concluded that surface aeration would be the ideal solution to control this breeding because of the following reasons:

1. Surface turbulence will prevent mosquitoes from laying eggs on water as mosquitoes can lay eggs only if the water is completely still.
2. If they do succeed in laying eggs, the eggs may drown or get damaged with the turbulence.
3. If the eggs hatch, the larvae will not be able to remain on the turbulent surface and get exhausted in the process of diving down and resurfacing.
4. As the larvae will not be able to remain on the surface and breathe, they will suffocate and ultimately die.
5. Moreover, surface aeration will reduce anaerobic bacterial development and deplete larval nutrition from the microlayer.

Having concluded that theoretically surface aeration is the key to controlling mosquito breeding, I went on to verify my hypothesis through experiment.

Step 3: Building the Device

The device comprises of the following parts:

Bubble aeration

I chose bubble aeration to create surface turbulence as it requires less power and maintenance than other methods of aeration, such as the use of an impeller or a fountain. For this prototype, I used a portable aquarium pump as a bubble generator.

Solar Power

As the aerator needs to run perpetually, it is not practical to make it battery-powered as the battery would have to be replaced often. So I made the device solar powered. Here, I’ve used a 6v 3w panel.

Night-activation

As most mosquitoes lay eggs between dusk and dawn, the device would be most effective at night. And so with the help of an LDR, which is a light intensity sensor, the device runs only when it’s dark. During the day, the solar panel charges Li-ion batteries and these batteries run the aerator at night.

Timer

A 555 timer circuit switches the pump on and off at intervals of 10 minutes to increase the life of the pump.

Automatic Start

In the case of rainwater, roadwork and construction sites, no arrangements are made to treat such temporary water bodies that are potential breeding grounds.

So to deal with this problem, the aeration device automatically starts when it comes in contact with water so that it can be installed in a catchment area and when water gets collected, it starts running immediately and leaves no room for mosquito breeding.

Alarm

The device also includes an inbuilt alarm to alert if the water body dries up or someone tries to remove the device from water.

Step 4: Get your hands dirty

This is the best part of the project...building the circuit! It takes no time to build this circuit which could potentially save you from those nasty mosquito bites. So get tinkering!

Components:

1. 6V 450mA Solar Cell
2. Portable aquarium aerator
3. 2 x Lithium Ion Rechargeable Batteries (laptop batteries - 18650A)
4. Piezo Buzzer
5. Perfboard
6. 555 Timer IC
7. 3 x 2N3904 NPN Transistors
8. BD135 NPN Transistor
9. Heat sink
10. Capacitors - 470 uF, 0.1 uF
11. Resistors - 220 ohms, 470 ohms, 2 x 10 k, 100k, 1M.
12. Indicator LED
13. Toggle switch
14. Jumpers

Electronic Parts:

1. 6V 450mA Solar Cell
2. Portable aquarium aerator
3. 2 x AA Rechargeable Batteries (I used 2 AA alkaline batteries as I did not have rechargeable ones)
4. Piezo Buzzer
5. Perfboard
6. 555 Timer
7. 3 x 2N3904 NPN Transistors
8. BD135 NPN Transistor
9. Heat sink
10. Capacitors - 470 uF, 0.1 uF
11. Resistors - 220 ohms, 470 ohms, 2 x 10 k, 100k, 1M.
12. Indicator LED
13. Toggle switch
14. Jumpers

Other materials:

1. Casing
2. 3 x 2" Stainless Steel bolts (that will serve as water probes)
3. PVC pipe and fittings
4. Miscellaneous tools

Step 5: Observation, Experimentation and Results

To test the device, I installed it in a small pond where rainwater had recently collected.

I waited until mosquito larvae began appearing in the pool to ensure that the pool was suitable for mosquito breeding. About three days after the larvae were born, I installed the aerator in the pond and observed the larval population in the pond. The results of the experiment are tabulated in the image above (I did not provide photos of the experiment as the larval population in the pond was not visible in the photos).

The experiment shows that while the aerator was not sufficiently powerful to suffocate and kill the full-grown larvae, within two hours it wiped out the majority of the young larval population and ensured a mosquito-free water body thereafter.

Step 6: A Mosquito-free Tomorrow

My observations have shown that, by preventing water stagnation by means of aeration, it is possible to control mosquito breeding and thereby control the proliferation of malaria.

The aeration device that I have built costs less than $ 10. Considering that every year, the global medical expenditure on malaria control amounts to over US$ 6 billion, ubiquitously installing this device in villages and cities would cost only a fraction of that amount.

I hope that, one day this cost effective and sustainable device will save the world valuable money and priceless lives.

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TRANSFORMER -- HOW IT'S DESIGNED?!!!

Transformer Construction

The construction of a simple two-winding transformer consists of each winding being wound on a separate limb or core of the soft iron form which provides the necessary magnetic circuit. This magnetic circuit, know more commonly as the “transformer core” is designed to provide a path for the magnetic field to flow around, which is necessary for induction of the voltage between the two windings.

However, this type of transformer construction were the two windings are wound on separate limbs is not very efficient since the primary and secondary windings are well separated from each other. This results in a low magnetic coupling between the two windings as well as large amounts of magnetic flux leakage from the transformer itself. But as well as this “O” shapes construction, there are different types of “transformer construction” and designs available which are used to overcome these inefficiencies producing a smaller more compact transformer.

The efficiency of a simple Transformer Construction can be improved by bringing the two windings within close contact with each other thereby improving the magnetic coupling. Increasing and concentrating the magnetic circuit around the coils may improve the magnetic coupling between the two windings, but it also has the effect of increasing the magnetic losses of the transformer core.

As well as providing a low reluctance path for the magnetic field, the core is designed to prevent circulating electric currents within the iron core itself. Circulating currents, called “eddy currents”, cause heating and energy losses within the core decreasing the transformers efficiency.

These losses are due mainly to voltages induced in the iron circuit, which is constantly being subjected to the alternating magnetic fields setup by the external sinusoidal supply voltage. One way to reduce these unwanted power losses is to construct the transformer core from thin steel laminations.

In all types of transformer construction, the central iron core is constructed from of a highly permeable material made from thin silicon steel laminations assembled together to provide the required magnetic path with the minimum of losses. The resistivity of the steel sheet itself is high reducing the eddy current losses by making the laminations very thin.

These steel transformer laminations vary in thickness’s from between 0.25mm to 0.5mm and as steel is a conductor, the laminations are electrically insulated from each other by a very thin coating of insulating varnish or by the use of an oxide layer on the surface.

Transformer Construction of the Core

Generally, the name associated with the construction of a transformer is dependant upon how the primary and secondary windings are wound around the central laminated steel core. The two most common and basic designs of transformer construction are the Closed-core Transformer and the Shell-core Transformer.

In the “closed-core” type (core form) transformer, the primary and secondary windings are wound outside and surround the core ring. In the “shell type” (shell form) transformer, the primary and secondary windings pass inside the steel magnetic circuit (core) which forms a shell around the windings as shown below.

Transformer Core Construction

 

In both types of transformer core design, the magnetic flux linking the primary and secondary windings travels entirely within the core with no loss of magnetic flux through air. In the core type transformer construction, one half of each winding is wrapped around each leg (or limb) of the transformers magnetic circuit as shown above.

The coils are not arranged with the primary winding on one leg and the secondary on the other but instead half of the primary winding and half of the secondary winding are placed one over the other concentrically on each leg in order to increase magnetic coupling allowing practically all of the magnetic lines of force go through both the primary and secondary windings at the same time. However, with this type of transformer construction, a small percentage of the magnetic lines of force flow outside of the core, and this is called “leakage flux”.

Shell type transformer cores overcome this leakage flux as both the primary and secondary windings are wound on the same centre leg or limb which has twice the cross-sectional area of the two outer limbs. The advantage here is that the magnetic flux has two closed magnetic paths to flow around external to the coils on both left and right hand sides before returning back to the central coils.

This means that the magnetic flux circulating around the outer limbs of this type of transformer construction is equal to Φ/2. As the magnetic flux has a closed path around the coils, this has the advantage of decreasing core losses and increasing overall efficiency.

Transformer Laminations

But you may be wondering as to how the primary and secondary windings are wound around these laminated iron or steel cores for this types of transformer constructions. The coils are firstly wound on a former which has a cylindrical, rectangular or oval type cross section to suit the construction of the laminated core. In both the shell and core type transformer constructions, in order to mount the coil windings, the individual laminations are stamped or punched out from larger steel sheets and formed into strips of thin steel resembling the letters“E’s”, “L’s”, “U’s” and “I’s” as shown below.

Transformer Core Types

 

These lamination stampings when connected together form the required core shape. For example, two “E” stampings plus two end closing “I” stampings to give an E-I core forming one element of a standard shell-type transformer core. These individual laminations are tightly butted together during the transformers construction to reduce the reluctance of the air gap at the joints producing a highly saturated magnetic flux density.

Transformer core laminations are usually stacked alternately to each other to produce an overlapping joint with more lamination pairs being added to make up the correct core thickness. This alternate stacking of the laminations also gives the transformer the advantage of reduced flux leakage and iron losses. E-I core laminated transformer construction is mostly used in isolation transformers, step-up and step-down transformers as well as auto transformers.

Transformer Winding Arrangements

Transformer windings form another important part of a transformer construction, because they are the main current-carrying conductors wound around the laminated sections of the core. In a single-phase two winding transformer, two windings would be present as shown. The one which is connected to the voltage source and creates the magnetic flux called the primary winding, and the second winding called the secondary in which a voltage is induced as a result of mutual induction.

If the secondary output voltage is less than that of the primary input voltage the transformer is known as a “Step-down Transformer”. If the secondary output voltage is greater then the primary input voltage it is called a “Step-up Transformer”.

Core-type Construction

The type of wire used as the main current carrying conductor in a transformer winding is either copper or aluminium. While aluminium wire is lighter and generally less expensive than copper wire, a larger cross sectional area of conductor must be used to carry the same amount of current as with copper so it is used mainly in larger power transformer applications.

Small kVA power and voltage transformers used in low voltage electrical and electronic circuits tend to use copper conductors as these have a higher mechanical strength and smaller conductor size than equivalent aluminium types. The downside is that when complete with their core, these transformers are much heavier.

Transformer windings and coils can be broadly classified in to concentric coils and sandwiched coils. In core-type transformer construction, the windings are usually arranged concentrically around the core limb as shown above with the higher voltage primary winding being wound over the lower voltage secondary winding.

Sandwiched or “pancake” coils consist of flat conductors wound in a spiral form and are so named due to the arrangement of conductors into discs. Alternate discs are made to spiral from outside towards the centre in an interleaved arrangement with individual coils being stacked together and separated by insulating materials such as paper of plastic sheet. Sandwich coils and windings are more common with shell type core construction.

Helical Windings also known as screw windings are another very common cylindrical coil arrangement used in low voltage high current transformer applications. The windings are made up of large cross sectional rectangular conductors wound on its side with the insulated strands wound in parallel continuously along the length of the cylinder, with suitable spacers inserted between adjacent turns or discs to minimize circulating currents between the parallel strands. The coil progresses outwards as a helix resembling that of a corkscrew.

Transformer Cores

The insulation used to prevent the conductors shorting together in a transformer is usually a thin layer of varnish or enamel in air cooled transformers. This thin varnish or enamel paint is painted onto the wire before it is wound around the core.

In larger power and distribution transformers the conductors are insulated from each other using oil impregnated paper or cloth. The whole core and windings is immersed and sealed in a protective tank containing transformer oil. The transformer oil acts as an insulator and also as a coolant.

Transformer Dot Orientation

We can not just simply take a laminated core and wrap one of the coil configurations around it. We could but we may find that the secondary voltage and current may be out-of-phase with that of the primary voltage and current. The two coil windings do have a distinct orientation of one with respect to the other. Either coil could be wound around the core clockwise or anticlockwise so to keep track of their relative orientations “dots” are used to identify a given end of each winding.

This method of identifying the orientation or direction of a transformers windings is called the “dot convention”. Then a transformers windings are wound so that the correct phase relations exist between the winding voltages with the transformers polarity being defined as the relative polarity of the secondary voltage with respect to the primary voltage as shown below.

Transformer Construction using Dot Orientation

 

The first transformer shows its two “dots” side by side on the two windings. The current leaving the secondary dot is “in-phase” with the current entering the primary side dot. Thus the polarities of the voltages at the dotted ends are also in-phase so when the voltage is positive at the dotted end of the primary coil, the voltage across the secondary coil is also positive at the dotted end.

The second transformer shows the two dots at opposite ends of the windings which means that the transformers primary and secondary coil windings are wound in opposite directions. The result of this is that the current leaving the secondary dot is 180o “out-of-phase” with the current entering the primary dot. So the polarities of the voltages at the dotted ends are also out-of-phase so when the voltage is positive at the dotted end of the primary coil, the voltage across the corresponding secondary coil will be negative.

Then the construction of a transformer can be such that the secondary voltage may be either “in-phase” or “out-of-phase” with respect to the primary voltage. In transformers which have a number of different secondary windings, each of which is electrically isolated from each other it is important to know the dot polarity of the secondary windings so that they can be connected together in series-aiding (secondary voltage is summed) or series-opposing (the secondary voltage is the difference) configurations.

The ability to adjust the turns ratio of a transformer is often desirable to compensate for the effects of variations in the primary supply voltage, the regulation of the transformer or varying load conditions. Voltage control of the transformer is generally performed by changing the turns ratio and therefore its voltage ratio whereby a part of the primary winding on the high voltage side is tapped out allowing for easy adjustment. The tapping is preferred on the high voltage side as the volts per turn are lower than the low voltage secondary side.

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