Generating electricity from mud

Research conducted by University of Massachusetts microbiologists and reported in Science concludes that certain micro organisms can transform organic matter commonly found at the bottom of the ocean into electrical energy.

Aside from raising the possibility that microbes someday could be used to produce power in subsurface settings, the findings have implications for many industrial and military applications, according to Derek R. Lovley, U Mass microbiologists.

An understanding of how microbes generate and use electrical energy may also prompt the development of new technologies to decontaminate polluted water and sediment containing organic materials, including petroleum and other aromatic hydrocarbons, he says.

In the Science article, Lovley explains how the team used water and sediment from Boston Harbour, a collection of mason jars, ordinary electrical wiring, and sterile graphite electrodes to determine the science behind the mechanics of a simple, sediment battery.

The researchers added  a layer of common mud to water in the jars, put one graphite electrode in the mud, another in overlying water. The resulting electrical current was strong enough to activate a light bulb, or a simple computer.

Through more refined experiments, Lovley's group found that a family of energy-harvesting micro organisms, commonly referred to as Geobacters, were key to the production of the electrical current.

Whereas most life forms, including humans, get their energy by oxidizing organic compounds with oxygen, Geobacters can grow in environments lacking oxygen by using the iron naturally present in soil, in place of oxygen. This new research demonstrates that Geobacters can also substitute an unnatural substance, such as an electrode, for the iron, according to Lovley.

A large number of a Geobacter species known as Desulfuromonas acetoxidans (D. acetoxidans) were found on the anode end of the primitive batteries. When the researchers destroyed the D. acetoxidans in the sediment, the current stopped.

Lovley's group also has found that some Geobacters can convert toxic organic compounds, such as toluene, to electricity. Lovley says this suggests that some Geobacters can be used to harvest energy from waste matter, or can be included in technology used to clean up subsurface environments contaminated organic matter, especially petroleum.

Earlier studies had shown bacteria could produce electricity  under artificial conditions in which special chemicals were added, but the UMass study was the first to prove that the nearly ubiquitous microbes living in a typical marine environment could produce electricity under the conditions naturally found in that environment.

"Once we know more about the genome of Geobacters, we will be able to manipulate these organisms to make them receptive to a variety of organic or inorganic contaminants. Theoretically, when they begin to degrade the contaminant, they will throw electrons on an electrode, and that could set off a light, a sound or some other form of signal," Lovley said.

An understanding of how this phenomenon operates has a number of extremely timely applications, especially in developing technologies to recognize toxins and organic contaminants.

Lovley cites, for example, the potential for using such technology to develop military equipment that could alert soldiers to the presence of toxins or biological warfare agents in the immediate environment.

[Source: The Hindu - 24th Jan 2002] 

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The role of an electrical engineer

Cost control is the buzzword today across companies. Here we take a look at what role an electrical engineer can play in helping his company control costs.

By CN Singh

In the era to globalisation, all types of business and stiff competition in the market have forced companies to restructure their business policy, marketing strategy, production process, human resources, quality control, etc. The ultimate aim is to reduce the cost of the final product.

But no cost control exercise will be effective and result oriented until it is supported by the top to bottom elements of the organization. The goal and standard of the company should be well communicated throughout the organization.

Here we have to consider the broad spectrum of an organization and hence an organisation is not your permanent employer. The organization is a combination of all those people involved directly or indirectly in any type of business or services with the company and even a good perception of the security guard standing in front of the office gate is a positive contribution towards the organization.

Cost control is not a philosophy but it is a practical-oriented exercise and the measure of the cost control is the balance sheet of the company. So how an electrical engineer may play a vital role in cost control programme of a company are as follows:

The role of an electrical engineer in the industry depends upon the type of industry, duty, responsibility and position held. Electrical engineers are doing many types of job from marketing to maintenance.

As a maintenance engineer in any industry may it be manufacturing, shipping, cement, fertilizer, petroleum, chemical, plastic, construction, power plant, pharmaceutical, sugar and paper, an electrical engineer plays a very important role in the operation of the factory.

For a successful contribution to the cost control exercise an electrical engineer should have certain qualifications and qualities. As an electrical engineer he should have the ability to interpret the company business plan and translate it into action within overall policies of the company. He should possess strong leadership skills to plan and mobilize scarce resources. He should be able to carry out preventive, predictive, schedule and routine maintenance. He should be able to develop an organization capable of exploiting best technological practices. Equipped with the above qualities he will achieve success in cost control exercise.

Self development for the successful operation of quality cost control programme is imminent for the electrical engineer, since cost control is an approach rather than a technique. It depends very much on individual talent. He should keep the objective clear, simple and short and try to eliminate unnecessary activities. The greatest saving arises from elimination of unnecessary activities and components and this should be the line of first attack.

He needs to develop a capability of meeting time target for assignment entrusted to him and also should have ability to offer innovative and creative solution. In brief, an electrical engineer aspiring for cost control exercise should have the quality of a good manager in all respect.

Scope of work and responsibilities of an electrical engineer are as under. It may change depending upon the type of industry.

• Maintenance of plant.

• Energy conservation

• Modification and upgradation of plant equipments.

• Managing electrical spares and better logistic control of electrical related materials and spares.

• Selecting the right contractor.   

Maintenance 

Maintenance of plant, electrical machineries and other associated equipment requires to be looked after by the electrical engineer. The most advanced maintenance management system is predictive and preventive maintenance using computer aided inputs and database management techniques. But it is not enough to rely on this programme as there would be incidence of sudden break down of equipments in operation and that is a testing time.

The sudden break down should be rectified in quick response so that the break down time could be limited. To cope with such unpredicted problem the only solution is having the ability to work in organized manner with job knowledge. There are occasions when in a hurry the job is spoiled and the cost of rectification increases.

The maintenance programme varies from industry to industry. So it is the duty of electrical engineer to study the process, system, plant setup, equipment design, production system and economy.

Now-a-days a trend is being followed by most of the organization that almost all jobs are being done by the contractor. In some organization the permanent staff are put on ideal or given non-productive job. This practice will have negative effect on quality cost reduction programme hence there is a need of in-depth study of work distribution, so that the job which can be performed by the organization staff efficiently could not go to the less efficient people.

Keeping the permanent staff ideal or giving them less productive work is not a wise decision for the organization. This happens most of the time due to the corrupt official who are interested in commission rather than organizational work. If the job goes to the contractor there is a need of strict supervision in day to-day work. Before awarding the job it necessitates to scrutinize the contractors qualification in all respect. And, also confirm that he would be able to complete the job in stipulated time, with required quality standard.

Energy Conservation

In cost control exercise energy conservation is the most important area to be considered since the energy cost is increasing day-by-day for the same unit of production and it has a considerable amount of bearing on the balance sheet of the company. As a maintenance engineer he should train the team and himself and must have knowledge of modern technological development in the field of energy conservation. The efficient energy management is no longer worthy of debate alone but it demands immediate action. Now time has come for industries to improve the energy conservation programme to control the ever increasing energy bill. An electrical engineers is well known to all the working of electrical related system and machineries and therefore he has the ability to conserve the electricity in efficient manner. Conservation of electricity would not only result in cost reduction but also help to conserve environment. It is rightly said that energy is like time, conservation once missed, savings are lost for ever.

Following are the few steps to be taken by the electrical engineer:

• Generate interest in energy conservation and sustain the interest with new ideas and activities.

• Maintain summaries of energy purchase, and consumption and prepare report on energy.

• Identify area of plant activities which required detail study and give priority to such activities.

• Give specialist advice to purchasing, planning production and other function of all aspects of energy conservation, especially on long-term implications.

• Get the detail audit of energy consuming done.

The demand side management play vital role in the process of energy cost control. In this regard few important options are as follows:

1. Use of energy efficient motors. 

2. Installation of variable speed drives.

3. Development of good house keeping measures.

4. Improvement in electric ARC furnace 

5. Study the time of day tariff.

6. Use of high efficiency sodium vapour lamps 

7. Use of compact fluorescent lamps.

8. Power factor improvement 

9. Industrial co-generation

10. Use of non-conventional source of energy.

For successful cost control it is important to review the result of the energy management programme to determine whether the objective and expected saving has been achieved.

Material Management

Although an electrical engineer in plant is not directly involved in material purchase but may contribute his/her knowledge in the process of purchasing items related to his work so that wrong quality and quantity can be avoided. This will pay back in the form of cost control to the plant operation. Knowledge of material in store for electrical use is equally important. While ordering the purchase of the materials , identification of right supplier is sure to contribute towards cost reduction. Keeping the electrical spares in well arranged, orderly and safe place to avoid any pilferage is also necessary. Ordering right type of material is right quantity, in right time is imminent for cost control exercise. Material purchased in hurry and lying in store without use is bound to disturb cost control exercise. Before ordering/purchasing any material equipments, items ask the following questions.

• Purpose :      What is being done?

• Place     :      Where it is being done?

• Person   :      Who is doing it?

• Time      :      When is it being done?

• Method  :      How it is being done?

Conclusion

Cost reduce is simply prevention of waste within the existing environment and is made of agreed operating method for which standard has been developed. An electrical engineer can contribute his/her share by efficient implementing the above discussed methods and procedures. Keeping in mind that cost reduction is not a special exercise carried out each time when management notices that the profit margin is falling but, it should be a routine activity carried out consistently throughout the whole organization all the time.

[Source: Electrical Engineering Update - Nov-Dec 2000]

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U.S. scientists develop magnetic refrigerator

Scientists at the Ames Laboratory say they have created the world's first magnetic refrigerator, which some day may save consumers money on energy bills and be better for the environment.

"We're witnessing history in the making," Karl Gschneider Jr, senior metallurgist at the U.S. Department of Energy lab, said on Monday.

Laboratory researchers have worked for years to develop magnetic refrigeration as an alternative to traditional cooling systems which emit gases that contribute to global warming.

The new refrigerator uses a special metal that heats up when exposed to a magnetic field, then cools when the magnetic field is removed. It is the first device to operate at room temperature and use a permanent magnet  rather than large, awkward superconducting magnets.

The rotary design features a wheel that is constructed of an alloy known as gadolinium which heats up when passed through a high-powered magnet. As the material leaves the magnetic field, the material cools down.

The result is a system that is nearly silent, because it is vibration-free.

Gschneider said magnetic refrigeration could some day power air conditioners, freezers and other commercial and household systems. He said the technology also would save money because the magnets do not require energy inputs to make them work.

"So the only energy it takes is the electricity for the motors to spin the wheel and drive the water pumps," he said. Initially the new appliances would run on 110 volts of power, but battery-operated versions are a possibility in the future, Gschneider said.

A break through occurred at the Ames  Laboratory when researchers Sasha Pecharsky and Vitalji Pecharsky developed a process for producing large quantities of gadolinium, which is capable of producing a stronger magnetic field and improves the refrigerator's efficiency.

The Ames scientists are developing magnetic refrigeration for Astronautics Corp. of America of Madison, which wants to market the technology to the public. The company took over the concept from the Los Alamos National Laboratory in 1985 and devoted millions of dollars to research.

The Department of Energy and Astronautics Corp. are sharing the cost of the project, Vitalji Pecharsky said. The Ames Laboratory has spent about $2 million in federal money on the concept, he said.

The researchers hope commercial production will start in about a year with a major refrigeration or air conditioning company purchasing the patent rights to manufacture appliances. Consumers probably won't see the first model for sale for about eight years, Gschneider said.

Gschneider said the new appliances will likely cost more than the top-of-the-line products on the market today, but will come down in cost as manufacturers produce more.

He said he has estimated that within five years, the new appliance will have saved enough money through more efficient operation to pay for the higher up-front purchase price.

Magnetic refrigeration was discovered by scientists in the 1920s, with slow improvements about every 20 years, Gschneider said.

[Source: The Times of India - 2nd January 2002] 

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Diesel Engine Technology 

Basic principles and recent innovations

Diesel engines can vary significantly in size, weight per unit of power generated and arrangement of components. But in one respect, they are similar. They are essentially intermittent-combustion piston cylinder devices, unlike turbines that have continuous combustion.

Diesel engines are also sometimes called compression-ignition engines. This is because, for the initiation of combustion, these engines rely on air heated by compression rather than by an electric spark. The engine gains its energy by burning fuel, which is injected or sprayed into the compressed hot air charge within the cylinder. Since the air is heated to a temperature greater than the temperature at which the injected fuel can ignite (auto-ignition temperature), the fuel spontaneously reacts with oxygen in the air and burns. 

Fuel Injection

Precise control of fuel injection is critical to the performance of a diesel engine. At present most of the engines have high energy and high pressure injection systems capable of achieving  fine atomisation. for achieving  economy, the fuel is injected at constant pressure over a specified output range. Hydraulic or electronic governors, with various engine protection functions, regulate the supply of fuel according to engine speed and load. Heavy fuel compatibility is achieved by incorporating a water circuit for cooling injector nozzles.

Efficiency

The most notable feature of a diesel engine is its efficiency. The thermal efficiency of a diesel engine is around 45 per cent. By compressing air rather than using an air-fuel mixture, the diesel engines is not limited by the pre-ignition problems that plague high compression spark-ignition engines. Thus, higher compression ratios can be achieved with diesel engines and therefore, higher cycle efficiencies can be realised.

Stroke type

Diesel engines can be subdivided into two groups depending on whether the operating cycle is completed in two or four strokes of the piston...

Four stroke:
In a four-stroke engine, with the inlet valve open, the piston first descends on the intake stroke. Air is drawn into the cylinder by the partial vacuum thus created. This is compressed (heated) as the piston ascends on the compression stroke with both valves closed.

As the end of the stroke is approached and the auto-ignition temperature is reached, fuel is introduced into the cylinder. The power stroke follows, with both valves still closed and the gas pressure, due to the expansion of the burnt gas, pressing on the piston crown. During the exhaust stroke, the ascending piston forces the spent products of combustion through the open exhaust valve. The cycle then repeats itself. Each cycle thus requires four stokes of the piston and two revolutions of the crankshaft.

Two stroke:
In the two-stroke cycle, the compression and power stroke of the four-stroke cycle are carried out without the inlet and exhaust strokes. In short, the two-stoke cycle is completed in one upstroke and one downstroke of the piston and a single revolution of the crankshaft.

Comparison

The two-stroke engine theoretically gives twice the power for a given bore, stroke and speed, thus reducing engine weight and cost. The four-stroke engine with the same bore, stroke and speed, however, is more fuel efficient than the two-stroke engine.

A disadvantage of the four-stoke engine is that only half as many power strokes are completed as in the two-stroke cycle and only half as much power can be expected from an engine of a given size operating at a given speed. The four-stroke cycle, however, provides more positive clearing out of exhaust gases an reloading of the cylinders, reducing the amount of loss of fresh charge to the exhaust.

In practice, it has been observed that four-stroke medium-speed, heavy fuel-fired diesel engines are favoured for setting up  captive as well as utility power plants of 3 MW to 50 MW capacity as the initial investment is lower than that for four-stroke low-speed engines.

[Source: Powerline - November 2001]

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Dreaming of the potential of thermocouple devices? Well, perhaps not but maybe you should. The science journal Nature says there has been a major breakthrough recently in the world of thermoelectric materials.

Scientists funded by the Office of Naval Research and the Defence Advanced Research Projects Agency have taken a field that has stagnated for over forty years and come up with a very high efficiency thermocouple device that could someday make both freon-dependant refrigerators, as well as power generators, obsolete.

By passing a current through thousands of super-thin layers of two different semi-conducting materials, scientists at the Research Triangle Institute (RTI) in North Carolina can make something hotter or colder (depending on which way the current flows) over 20,000 times faster than anything we have today.

In addition to the astonishing cooling applications of such a device, these thermoelectric material could someday be used to convert heat into electrical energy in an efficient manner than is possible now. In the 1990s ONR set out to discover and understand the science that would ead to new thermoelectric materials with potentially higher efficiency.

RTI had a unique idea to separate electrical transport from thermal transport through an artificially engineered material based on a semiconductors super lattice.

Over the years they had to surmount many obstacles: first they had to develop a chemical vapour deposition method to make thin films with repeating structures only tens of angstroms thick.

Next they had to measure the properties of the structure.

Finally they had to apply what they'd discovered and make a prototype device. This marks the beginning of a new era in thermoelectrics.

Ultimately these new materials will be engineered into many devices-eventually into plug-in modules-all at an affordable price.

[Source: The Hindu - 13th December 2001]    

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Converting excess heat into electricity

A Semiconductor technology that could allow efficient, affordable production of electricity from a variety of energy sources has been invented by an MIT scientist. It does not use a turbine or similar generator. The researchers will present the work at a poster session during the Materials Research Society's fall meeting in Boston.

Many researchers have worked to convert heat to electricity directly without the moving parts of a generator. Among other advantages, such a device would be virtually silent, vibration-free, and low in maintenance costs. Until now, however, the efficiency of such devices has been a problem. The amount of electricity they produce from a given amount of energy has been low.

The new device is two times more efficient than its closest commercial competitor write Associate Professor Peter L. Hagelstein of MIT's Department of Electrical Engineering and Computer Science and Dr. Yan Kucherov of ENECO, Inc. The technology could have major implications for recovery of waste heat from power plants and automobiles.

For example, the heat lost through engine exhausts might be captured by the technology and converted into electricity to augment or replace a vehicle's electrical and air conditioning systems. It could also be important in the primary generation of electrical power.

The technology is based on thermionics, which originated nearly a century ago with the basic vacuum tube, a device that consisted of two parallel conductive plates (cathode and anode) separated by a vacuum gap. In this high temperature tube, electrons boiled off the cathode, traversed the gap and then were absorbed into the colder anode. The conversion of heat to electricity "occurs as the electrons transport 'up-hill' against an electric field in the gap region," said Hagelstein. These early "vacuum gap" designs had prohibitive manufacturing costs and higher operating temperatures above 1,000 degrees Celsius (about 2,000 degrees Fahrenheit) which has limited the technology to nuclear-powered converters in space probes, satellites and special military systems.

The new technology essentially replaces the traditional vacuum gap with a multi-layer semiconductor structure. Hagelstein credits Professor Gerald D. Mahan of the University of Tennessee with first suggesting such a solid-state implementation of vacuum thermionics. Hagelstein and Kucherov demonstrated two basic enabling physical mechanisms that allow this technology to be implemented practically. Louis D. Smullin, MIT Professor of Electrical Engineering, Emeritus, said of the new work: "Thermocouples and thermopiles have been with us for over a century.

By careful selection of materials, ENECO scientists are creating highly efficient, solid state conversion devices, called "thermal diodes," that will operate from 200 - 450 degree Celsius --typical temperatures for waste heat and for concentrated solar radiation.

An added plus: the technology is environmentally friendly. "Solid state thermal to electric energy conversion converts energy due to how electrons transport in the conductor, a process that generates no pollution," Hagelstein said. He noted, however, that some of the materials used in the present generation of devices are toxic, which will affect the eventual disposal of the devices.

[Source: The Hindu, 6th Dec 2001] 

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Precise semiconductors

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Rise of smart materials and structures

Can a material possess intelligence? The answer depends on what one means by intelligence. One tends to associate intelligence with what a human brain can do: perception, memory, thinking, problem solving, learning, creativity, etc.

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Chemists create plastic magnet

A Team of chemists at the University of Nebraska-Lincoln have created the world's first plastic magnets.

Andrzej Rajca, a professor of chemistry, Suchada Rajca, his wife and research partner as a research assistant professor at Nebraska, and doctoral canditate Jirawat Wongsriratanakul achieved this feat earlier this year. The results were published in the journal Science. "There are already known organic magnets, but they are based on crystals of small molecules," Rajca said. "What is unique about this research is this is the first organic polymer that can be said to be magnetic."

A polymer is a large, often chainlike molecule that may consist of repeated linked units of relatively small molecules. An organic polymer is carbon-based and therefore an organic polymer that is essentially a plastic magnet, no metal required. "This was predicted more than 30 years ago and a large volume of work has been done on this, especially in Japan and Europe," Rajca said. We essentially made larger and larger molecules with different arrangements of unpaired electrons in order to figure out how to make this polymer.

Rajca, said no one should except to stick a plastic magnet to a refrigerator door any time soon, however. That's because the magnetic polymers are unstable unless they are in an oxygen-free environment at temperatures below 10 degrees Kelvin (more than 440 degrees below zero Fahrenheit; absolute zero, the point at which all motion stops, is zero degrees Kelvin).

Nevertheless, he said he is relatively confident that the problems of stability and low temperatures can be overcome, if only because his team has already succeeded in providing one of the predictions made by Japanese theoretical chemist Noboru Mataga in 1968.

"Mataga predicted that it should be possible to do it (create organic magnetic polymers). He also predicted that it can be doneat room temperature," Rajca said. He added that he can only speculate about possible uses for the new polymers if (or when) the problems with stability and temperature are solved. To illustrate the point, he compared his team's discovery to the discovery of the first organic conducting polymers more than 20 years ago by a team that included Nebraska graduate and Nobel Prize winner Alan Heeger.

"At the time they were discovered, people thought they could be made into very light conducting wires that could replace metals as conductors of electricity," Rajca said. "But about 10 years ago, it was discovered that they can actually be used in a completely different way, as light-emitting diodes, and now several companies are actively working on that particular application. It turned out that these conducting polymers are not competitive as conductors.

New Scientist [Source: The Hindu - 22nd November 2001]

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The capacity addition in the last three years has been around 4,000 MW. The thermal sector has witnessed maximum addition in capacity. The last two years also witnessed an additional 440 MW coming from nuclear energy.

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Electricity generation has almost doubled in the last decade. Thermal sources have accounted for over 80 per cent of the generation. Hydel generation has remained more or less constant during the last 10 years.

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New Scientist [An Article from The Hindu]

Evergreen ‘diesel’ 

[Author: Madhumathi D. S.]

Q: How is the hole in the surgical needles produced?

[Source: Express News Service]

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Ocean thermal conversion plant in Tuticorin
Island nations – Mauritius Seychelles and Maldives- have sought India’s expertise in the setting up of ocean thermal energy conversion (OTEC) plants.

The Secretary, Union Department of Ocean Development (DoD), Dr. Harsh K. Gupta, said these countries have been sensitized to India’s efforts at setting up a 1 MW plant close to the Tuticorin harbour in Tamil Nadu.

The Tuticorin plant being executed by the National Institute of Ocean Technology (NIOT), Chennai, a constituent of the DoD will convert the thermal energy in the oceans into electricity by exploiting the temperature difference between the warm surface water (28 degree C) and cold deep-sea water (6 degrees C) at 1000 meter depth.

Dr. Gupta told that 1 MW plant is a technology demonstrator. Once demonstrated, OTEC plants will be replicated in Andaman & Nicobar Islands and Lakshadweep islands in a phased manner.

The DoD, which is the main funding department of the project, now part of the 16 ‘Jai Vigyan’ mission projects, could also lead to the setting up of larger plants with 25 MW capacity. These OTEC plants have the potential of providing pollution free renewable energy at a cost comparable to other fossil-fueled plants.

While the NIOT is the implementing organization, the National Ship Design and Research Center, Vishakhapatnam is an active participant. The Tuticorin Port Trust, Navy and Coast Guard along with the Dempo Shipyard, Goa and Turbotech, Bangalore are supporting in infrastructure and manufacture of sub-systems for the plant.

The Dempo Shipyard has already constructed the plant barge weighing approximately 500 tones. The barge named ‘Sagar Shakthi’ by the DoD will contain all the assembly of the OTEC plant.

A one-km long, 1 meter diameter HDPE pipe, which will bring cold sea water to the plant barge is also ready. It will be integrated with the OTEC plant barge soon. Once, this connection is established the plant will be ready for demonstration.

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Why take the pain of reaching out to switches when you can set them to turn on and off automatically, says PK Chauhan.

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Replacing switchgear with glasses

New Scientist [An Article from The Hindu]

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