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Electrical Topics Category

Light Emitting Polymer

Added on: February 13th, 2017 by Afsal Meerankutty No Comments

 The seminar is about polymers that can emit light when a voltage is applied to it. The structure comprises of a thin film of semiconducting polymer sandwiched between two electrodes (cathode and anode).When electrons and holes are injected from the electrodes, the recombination of these charge carriers takes place, which leads to emission of light .The band gap, ie. The energy difference between valence band and conduction band determines the wavelength (colour) of the emitted light.

They are usually made by ink jet printing process. In this method red green and blue polymer solutions are jetted into well defined areas on the substrate. This is because, PLEDs are soluble in common organic solvents like toluene and xylene .The film thickness uniformity is obtained by multi-passing (slow) is by heads with drive per nozzle technology .The pixels are controlled by using active or passive matrix.

It is a polymer that emits light when a voltage is applied to it. The structure comprises a thin-film of semiconducting polymer sandwiched between two electrodes (anode and cathode) as shown in fig.1. When electrons and holes are injected from the electrodes, the recombination of these charge carriers takes place, which leads to emission of light that escapes through glass substrate. The bandgap, i.e. energy difference between valence band and conduction band of the semiconducting polymer determines the wavelength (colour) of the emitted light.

The advantages include low cost, small size, no viewing angle restrictions, low power requirement, biodegradability etc. They are poised to replace LCDs used in laptops and CRTs used in desktop computers today.

Their future applications include flexible displays which can be folded, wearable displays with interactive features, camouflage etc.

MOCT (Magneto-Optical Current Transformer)

Added on: February 7th, 2017 by Afsal Meerankutty No Comments

An accurate current transducer is a key component of any power system instrumentation. To measure currents, power stations and substations conventionally employ inductive type current transformers. With short circuit capabilities of power system getting larger and the voltage level going higher the conventional current transducers becomes more bulky and costly.

It appears that newly emerged MOCT technology provides a solution for many of the problems by the conventional current transformers. MOCT measures the rotation angle of the plane polarized lights caused by the magnetic field and convert it into a signal of few volts proportional to the magnetic field.

Main advantage of an MOCT is that there is no need to break the conductor to enclose the optical path in the current carrying circuit and there is no electromagnetic interference.

Magneto Hydro Dynamic Power Generation

Added on: February 1st, 2017 by Afsal Meerankutty No Comments

When an electrical conductor is moved so as to cut lines of magnetic induction, charged particles in the conductor experience a force in a direction mutually perpendicular to the B field and to the velocity of the conductor. The negative charges tend to move in one direction, and the positive charges in the opposite direction. This induced electric field, or motional emf, provides the basis for converting mechanical energy into electrical energy. In conventional steam power plants, the heat released by the fuel is converted into rotational mechanical energy by means of a thermo cycle and the mechanical energy is then used to drive the electric generator. Thus two stages of energy conversion are involved in which the heat to mechanical energy conversion has inherently very low efficiency.

Also, the rotating machine has its associated losses and maintenance problems. In MHD generation, electrical energy is directly generated from hot combustion gases produced by the combustion of fuel without moving parts. The conventional electrical machines are basically electro mechanical converters while an MHD generator is heat engine operating on a turbine cycle and transforming the internal energy of gas directly into electrical energy.


Added on: January 25th, 2017 by Afsal Meerankutty No Comments

Generally when most people think about electronics, they may initially think of products such as cell phones, radios, laptop computers, etc. others, having some engineering background, may think of resistors, capacitors, etc. which are the basic components necessary for electronics to function. Such basic components are fairly limited in number and each having their own characteristic function.

Memristor theory was formulated and named by Leon Chua in a 1971 paper. Chua strongly believed that a fourth device existed to provide conceptual symmetry with the resistor, inductor, and capacitor. This symmetry follows from the description of basic passive circuit elements as defined by a relation between two of the four fundamental circuit variables. A device linking charge and flux (themselves defined as time integrals of current and voltage), which would be the memristor, was still hypothetical at the time. However, it would not be until thirty-seven years later, on April 30, 2008, that a team at HP Labs led by the scientist R. Stanley Williams would announce the discovery of a switching memristor. Based on a thin film of titanium dioxide, it has been presented as an approximately ideal device.

The reason that the memristor is radically different from the other fundamental circuit elements is that, unlike them, it carries a memory of its past. When you turn off the voltage to the circuit, the memristor still remembers how much was applied before and for how long. That’s an effect that can’t be duplicated by any circuit combination of resistors, capacitors, and inductors, which is why the memristor qualifies as a fundamental circuit element.

The arrangement of these few fundamental circuit components form the basis of almost all of the electronic devices we use in our everyday life. Thus the discovery of a brand new fundamental circuit element is something not to be taken lightly and has the potential to open the door to a brand new type of electronics. HP already has plans to implement memristors in a new type of non-volatile memory which could eventually replace flash and other memory systems

Pill Camera

Added on: January 12th, 2017 by Afsal Meerankutty No Comments

The aim of technology is to make products in a large scale for cheaper prices and increased quality. The current technologies have attained a part of it, but the manufacturing technology is at macro level. The future lies in manufacturing product right from the molecular level. Research in this direction started way back in eighties. At that time manufacturing at molecular and atomic level was laughed about. But due to advent of nanotechnology we have realized it to a certain level. One such product manufactured is PILL CAMERA, which is used for the treatment of cancer, ulcer and anemia. It has made revolution in the field of medicine. This tiny capsule can pass through our body, without causing any harm.

It takes pictures of our intestine and transmits the same to the receiver of the Computer analysis of our digestive system. This process can help in tracking any kind of disease related to digestive system. Also we have discussed the drawbacks of PILL CAMERA and how these drawbacks can be overcome using Grain sized motor and bi-directional wireless telemetry capsule .Besides this we have reviewed the process of manufacturing products using nanotechnology.Some other important applications are also discussed along with their potential impacts on various fields.

We have made great progress in manufacturing products. Looking back from where we stand now, we started from flint knives and stone tools and reached the stage where we make such tools with more precision than ever. The leap in technology is great but it is not going to stop here. With our present technology we manufacture products by casting, milling, grinding, chipping and the likes. With these technologies we have made more things at a lower cost and greater precision than ever before. In the manufacture of these products we have been arranging atoms in great thundering statistical herds. All of us know manufactured products are made from atoms. The properties of those products depend on how those atoms are arranged. If we rearrange atoms in dirt, water and air we get grass. The next step in manufacturing technology is to manufacture products at molecular level. The technology used to achieve manufacturing at molecular level is “NANOTECHNOLOGY”. Nanotechnology is the creation of useful materials, devices and system through manipulation of such miniscule matter (nanometer).Nanotechnology deals with objects measured in nanometers. Nanometer can be visualized as billionth of a meter or millionth of a millimeter or it is 1/80000 width of human hair.

Ac Synchronous Generators

Added on: January 23rd, 2016 by Afsal Meerankutty No Comments

AC Generators come in two basic types – synchronous and non-synchronous. Synchrono us generators lock in with the fundamental line frequency and rotate at a syn-chronous speed related to the number of poles similar to that of AC Synchronous motors. Synchronous generator stator windings are similar to a three-phase synchronous motor stator winding. Synchronous generator rotor fields may be either salient or non-salient pole. Salient Pole (also called spider or projected pole) means the rotor has distinct pole windings mounted on the rotor shaft using dovetail joints. These pole windings are wound around field poles. Salient Pole rotors are most commonly used in slow speed applications and tend to be at least six poles. Salient pole rotors typically have damper windings to reduce rotor oscillations (caused by large flux changes between the individual poles) during operation.

Compensation of Harmonic Currents Utilizing AHC

Added on: October 10th, 2013 by Afsal Meerankutty 2 Comments

In little more than ten years, electricity power quality has grown from obscurity
to a major issue.
Electronic converters and power electronics gave birth to numerous new applications, offering unmatched comfort, flexibility and efficiency to the customers. However, their proliferation during the last decade is creating a growing concern and
generates more and more problems: not only these electronic loads pollute the AC distribution system with harmonic currents, but they also appear to be very sensitive to the voltage distortion.
Then, electricity power quality is becoming a major issue for utilities and for their customers, and both are quickly adopting the philosophy and the limits proposed by the new International Standards (519-1992 IEEE, 61000.3-2/4 IEC).
Today, recent advances in power electronic technology are providing an unprecedented capability for conditioning and compensating harmonic distortion generated by the non-linear loads.
The case study presented in this paper demonstrates the role of the power source,the load and the AC distribution system as regards power quality. The benefit of harmonic cancellation equipment is clearly shown. Among the different technical
solutions, a shunt – current injection mode – active harmonic conditioner is evaluated, and detailed site measurements are presented as confirmation of the unsurpassed performances. This new innovative active conditioner appears to be the easiest of use, the most flexible, the most efficient and cost effective one

Thermo Acoustic Refrigeration

Added on: October 7th, 2013 by Afsal Meerankutty 2 Comments

Thermo acoustic have been known for over years but the use of this phenomenon to develop engines and pumps is fairly recent. Thermo acoustic refrigeration is one such phenomenon that uses high intensity sound waves in a pressurized gas tube to pump heat from one place to other to produce refrigeration effect. In this type of refrigeration all sorts of conventional refrigerants are eliminated and sound waves take their place. All we need is a loud speaker and an acoustically insulated tube. Also this system completely eliminates the need for lubricants and results in 40% less energy consumption. Thermo acoustic heat engines have the advantage of operating with inert gases and with little or no moving parts, making them highly efficient ideal candidate for environmentally-safe refrigeration with almost zero maintenance cost. Now we will look into a thermo acoustic refrigerator, its principle and functions.

Underwater Communication Systems

Added on: October 3rd, 2013 by Afsal Meerankutty 7 Comments

There is a high demand for underwater communication systems due to the increase in current human underwater activities. Underwater communication systems employ either sonar or electromagnetic waves as a means of transferring signals. These waves are different physically and electrically, and thus the systems that employ them also differ in their design architecture, wave propagation and devices used for emission and reception. As a result, the two systems have varying advantages and limitations. This paper presents an in-depth review of underwater communication based on sonar and electromagnetic waves, a comparison of the two systems and a discussion of the environmental impacts of using these waves for underwater communication. In the tradeoff between preserving the underwater environment and the need for underwater communication, it appears that underwater electromagnetic wave communication has the most potential to be the environmentally-friendly system of the future.

Sonar and Acoustic Waves Communication

Added on: October 3rd, 2013 by Afsal Meerankutty 1 Comment

In past previous years, the demand of underwater communication increases due to interest and underwater activities of human being. Underwater communication done with the help of sonar waves, electromagnetic waves and acoustic waves, these three waves are different in nature. This paper present an overview of sonar and acoustic waves underwater communication .In this it is also show acoustic wave communication is better than sonar wave communication. Addition with this the factors, which affect the acoustic wave communication, also explained.

Axial-Field Electrical Machines

Added on: September 25th, 2013 by Afsal Meerankutty 2 Comments

Axial-field electrical machines offer an alternative to the conventional machines. In the axial-field machine, the air gap flux is axial in direction and the active current carrying conductors are radially positioned. This paper presents the design characteristics, special features, manufacturing aspects and potential applications for axial-field electrical machines. The experimental from several prototypes, including d.c. machines, synchronous machines and single-phase machines are given. The special features of the axial-field machine, such as its planar and adjustable air gap, flat shape, ease of diversification, etc., enable axial-fled machines to have distinct advantages over conventional machines in certain applications, especially in special purpose applications. conventional radial field machines. The axial field electrical machines described in this paper are particularly suitable for d.c and synchronous machines where the double air gaps present no difficulties since these machines normally require fairly large air gaps to reduce the effect of armature reaction. One of the major objections to the use of AFMs lies in the difficulty on cutting the slots in their laminated cores.

Solar Power Satellites

Added on: March 22nd, 2012 by Afsal Meerankutty 5 Comments

The new millennium has introduced increased pressure for finding new renewable energy sources. The exponential increase in population has led to the global crisis such as global warming, environmental pollution and change and rapid decrease of fossil reservoirs. Also the demand of electric power increases at a much higher pace than other energy demands as the world is industrialized and computerized. Under these circumstances, research has been carried out to look into the possibility of building a power station in space to transmit electricity to Earth by way of radio waves-the Solar Power Satellites. Solar Power Satellites(SPS) converts solar energy in to micro waves and sends that microwaves in to a beam to a receiving antenna on the Earth for conversion to ordinary electricity.SPS is a clean, large-scale, stable electric power source. Solar Power Satellites is known by a variety of other names such as Satellite Power System, Space Power Station, Space Power System, Solar Power Station, Space Solar Power Station etc. One of the key technologies needed to enable the future feasibility of SPS is that of Microwave Wireless Power Transmission.WPT is based on the energy transfer capacity of microwave beam i.e; energy can be transmitted by a well focused microwave beam. Advances in Phased array antennas and rectennas have provided the building blocks for a realizable WPT system.

Geothermal Energy

Added on: March 21st, 2012 by Afsal Meerankutty No Comments

The word geothermal comes from the Greek words geo (earth) and therme ( heat). So, geothermal energy is heat from within the earth. We can use the steam and hot water produced inside the earth to heat buildings or generate electricity. Geothermal energy is a renewable energy source because the water is replenished by rainfall and the heat is continuously produced in the earth.

Historically , the first application of geothermal energy were for space heating , cooking and medical purposes . The earliest record of space heating dates back to 1300 in Iceland .In the early 1800s , geothermal energy was used on what was then a large scale by the conte Franceso de Laderel to recover boric acid . The first mechanical conversion was in 1897 when the steam of the field at Larderallo, Italy , was used to heat a boiler producing steam which drove a small steam engine . The first attempt to produce electricity also took place at Larderello in 1904 with an electricity generator that powered four light bulbs . This was followed in 1912 by a condensating turbine ; and by 1914, 8.5 MW of electricity was being produced . By 1944 larderello was producing 127MW. The Plant was destroyed near end of World war 2, but was fortunately rebuilt and expanded evevtually reached 360 MW in 1981.

Electronic Fuel Injection System

Added on: March 15th, 2012 by Afsal Meerankutty 1 Comment

In developed and developing countries considerable emphasis is being laid on the minimization of pollutants from internal combustion engines. A two-stroke cycle engine produces a considerable amount of pollutants when gasoline is used as a fuel due to short-circuiting. These pollutants, which include unburnt hydrocarbons and carbon monoxide, which are harmful to beings. There is a strong need to develop a kind of new technology which could minimize pollution from these engines.

Direct fuel injection has been demonstrated to significantly reduce unburned hydrocarbon emissions by timing the injection of fuel in such way as to prevent the escape of unburned fuel from the exhaust port during the scavenging process.

The increased use of petroleum fuels by automobiles has not only caused fuel scarcities, price hikes, higher import bills, and economic imbalance but also causes health hazards due to its toxic emissions. Conventional fuels used in automobiles emit toxic pollutants, which cause asthma, chronic cough, skin degradation, breathlessness, eye and throat problems, and even cancer.

In recent years, environmental improvement (CO2, NOx and Ozone reduction) and energy issues have become more and more important in worldwide concerns. Natural gas is a good alternative fuel to improve these problems because of its abundant availability and clean burning characteristics.


Added on: March 11th, 2012 by Afsal Meerankutty No Comments

ITER (originally an acronym of International Thermonuclear Experimental Reactor) is an international nuclear fusion research and engineering project, which is currently building the world’s largest and most advanced experimental tokamak nuclear fusion reactor at Cadarache in the south of France. The ITER project aims to make the long-awaited transition from experimental studies of plasma physics to full-scale electricity-producing fusion power plants. The project is funded and run by seven member entities – the European Union (EU), India, Japan, the People’s Republic of China, Russia, South Korea and the United States. The EU, as host party for the ITER complex, is contributing 45% of the cost, with the other six parties contributing 9% each.

The ITER fusion reactor itself has been designed to produce 500 megawatts of output power for 50 megawatts of input power, or ten times the amount of energy put in. The machine is expected to demonstrate the principle of getting more energy out of the fusion process than is used to initiate it, something that has not been achieved with previous fusion reactors. Construction of the facility began in 2007, and the first plasma is expected in 2019. When ITER becomes operational, it will become the largest magnetic confinement plasma physics experiment in use, surpassing the Joint European Torus. The first commercial demonstration fusion power plant, named DEMO, is proposed to follow on from the ITER project to bring fusion energy to the commercial market.
The same principle of sun is used to produce heat in ITER plant.

Polyfuses (PPTC)

Added on: March 7th, 2012 by Afsal Meerankutty 1 Comment

A fuse is a one time over current protection device employing fusible link that melts after the current exceeds a certain level for a certain length of time. Typically, a wire or chemical compound breaks the circuit when the current exceeds the rated value.

Polyfuse is a new standard for circuit protection .It is resettable. Technically, Polyfuses are not fuses but polymeric positive temperature coefficient thermistors (PPTC). Re-settable fuses provide over current protection and automatic restoration.

Broadband Over Powerline

Added on: March 7th, 2012 by Afsal Meerankutty No Comments

Despite the spread of broadband technology in the last few years, there are significant areas of the world that don’t have access to high-speed Internet. When weighed against the relatively small number of customers Internet providers would gain, the incremental expenditures of laying cable and building the necessary infrastructure to provide DSL or cable in many areas, especially rural , is too great. But if broadband could be served through power lines, there would be no need to build a new infrastructure. Anywhere there is electricity there could be broadband. Technology to deliver high-speed data over the existing electric power delivery network is closer to reality in the marketplace. Broadband OverPowerline, is positioned to offer an alternative means of providing high-speed internet access, VoicE over Internet Protocol (VoIP), and other broadband services, using medium – and low – voltage lines to reach customers’ homes and businesses. By combining the technological principles of radio, wireless networking, and modems, developers have created a way to send data over power lines and into homes at speeds between 500 kilobits and 3 megabits per second (equivalent to DSL and cable). By modifying the current power grids with specialized equipment, the BPL developers could partner with power companies and Internet service providers to bring broadband to everyone with access to electricity

Flying Windmills

Added on: March 4th, 2012 by Afsal Meerankutty No Comments

High Altitude Wind Power uses flying electric generator (FEG) technology in the form of what have been more popularly called flying windmills, is a proposed renewable energy project over rural or low-populated areas, to produce around 12,000 MW of electricity with only 600 well clustered rotorcraft kites that use only simple autogyro physics to generate far more kinetic energy than a nuclear plant can.

According to Sky WindPower; the overuse of fossil fuels and the overabundance of radioactive waste from nuclear energy plants is taking our planet once again down a path of destruction, for something that is more expensive and far more dangerous in the long run. FEG technology is just cheaper, cleaner and can provide more energy than those environmentally unhealthy methods of the past, making it a desirable substitute/alternative.

The secret to functioning High Altitude Wind Power is efficient tether technology that reaches 15,000 feet in the air, far higher than birds will fly, but creating restricted airspace for planes and other aircraft.

The same materials used in the tethers that hold these balloons in place can also hold flying windmills in place; and with energy cable technology getting ever lighter and stronger .Flying windmills appear to be 90 percent more energy efficient in wind tunnel tests than their land-based counterparts; that is three times more efficiency due to simple yet constantly abundant and effective high altitude wind power, available only 15,000 feet in the air by way of clustered rotor craft kites tethered with existing anti-terrorist technologies like those used on the Mexican/American border radar balloons.

High Altitude Wind Power offers itself as a clean and more powerful source of power generation than anything available on-the-grid at present and if Sky WindPower Corp. has their way, FEG technology and flying windmills will take the lead of a more sustainable future within the decade.

MEMS Switches

Added on: March 4th, 2012 by Afsal Meerankutty No Comments

Compound solid state switches such as GaAs MESFETs and PIN diodes are widely used in microwave and millimeter wave integrated circuits (MMICs) for telecommunications applications including signal routing, impedance matching networks, and adjustable gain amplifiers. However, these solid-state switches have a large insertion loss (typically 1 dB) in the on state and poor electrical isolation in the off state. The recent developments of micro-electro-mechanical systems (MEMS) have been continuously providing new and improved paradigms in the field of microwave applications. Different configured micro machined miniature switches have been reported. Among these switches, capacitive membrane microwave switching devices present lower insertion loss, higher isolation, better nonlinearity and zero static power consumption. In this presentation, we describe the design, fabrication and performance of a surface micro machined capacitive microwave switch on glass substrate using electroplating techniques.

Landmine Detection

Added on: March 4th, 2012 by Afsal Meerankutty No Comments

Landmines and unexploded ordnance (UXO) are a legacy of war, insurrection, and guerilla activity. Landmines kill and maim approximately 26,000 people annually. In Cambodia, whole areas of arable land cannot be farmed due to the threat of landmines. United Nations relief operations are made more difficult and dangerous due to the mining of roads. Current demining techniques are heavily reliant on metal detectors and prodders.

Technologies are used for landmine detection are:

  • • Metal detectors— capable of finding even low-metal content mines in mineralized soils.
    • Nuclear magnetic resonance, fast neutron activation and thermal neutron activation.
    • Thermal imaging and electro-optical sensors— detect evidence of buried objects.
    • Biological sensors such as dogs, pigs, bees and birds.
    • Chemical sensors such as thermal fluorescence— detect airborne and waterborne presence of explosive vapors.

In this discussion, we will concentrate on Ground Penetrating Radar (GPR). This ultra wide band radar provides centimeter resolution to locate even small targets. There are two distinct types of GPR, time-domain and frequency domain. Time domain or impulse GPR transmites discrete pulses of nanosecond duration and digitizes the returns at GHz sample rates. Frequency domain GPR systems transmit single frequencies either uniquely, as a series of frequency steps, or as a chirp. The amplitude and phase of the return signal is measured. The resulting data is converted to the time domain. GPR operates by detecting the dielectric contrasts in the soils, which allows it to locate even non metallic mines.

In this discussion we deal with buried anti-tank (AT) and anti-personnel (AP) landmines which require close approach or contact to activate. AT mines range from about 15 to 35 cm in size. They are typically buried up to 40cm deep, but they can also be deployed on the surface of a road to block a column of machinery. AP mines range from about 5 to 15cm in size. AT mines which are designed to impede the progress of destroy vehicles and AP mines which are designed to kill and maim people.

Power Monitoring System

Added on: March 3rd, 2012 by Afsal Meerankutty 1 Comment

The microcontroller-based power monitoring system is an electronic device used to continuously monitor the parameters of power such as voltage, current, frequency, etc at the various points of an electric or electronics devices. The entire system is controlled by the microcontroller (80C31) and it is the real time monitoring of various parameters. Thus the name “REAL TIME MONITORING OF HIGH CAPACITY (400KVA-600KVA) BATTERY BACK UP SYSTEM”. This system is an 8-channel device, which accepts 8 analog input signals and consist of analog multiplexer, A/D converter, ROM, RAM, buffer etc. The different channels are selected by simple switch operation. From the UPS the channels and alarms are given to the microcontroller and it will process and control the parameters.

Aerospace Flywheel Development

Added on: March 3rd, 2012 by Afsal Meerankutty No Comments

Presently, energy storage on the Space Station and satellites is accomplished using chemical batteries; most commonly nickel hydrogen or nickel cadmium. A flywheel energy storage system is an alternative technology that is being considered for future space missions. Flywheels offer the advantage of a longer lifetime, higher efficiency and a greater depth of discharge than batteries. A flywheel energy storage system is being considered as a replacement for the traditional electrochemical battery system in spacecraft electrical power systems. The flywheel system is expected to improve both the depth of discharge and working life by a factor of 3 compared with its battery counterpart. Although flywheels have always been used in spacecraft navigation and guidance systems, their use for energy storage is new. However, the two functions can easily be combined into a single system. Several advanced technologies must be demonstrated for the flywheel energy storage system to be a viable option for future space missions. These include high strength composite materials, highly efficient high speed motor operation and control, and magnetic bearing levitation.

Electrodynamic Tether

Added on: February 28th, 2012 by Afsal Meerankutty No Comments

Electrodynamic (ED) tether is a long conducting wire extended from spacecraft. It has a strong potential for providing propellant less propulsion to spacecraft in low earth orbit. An electrodynamic Tether uses the same principle as electric motor in toys, appliances and computer disk drives. It works as a thruster, because a magnetic field exerts a force on a current carrying wire. The magnetic field is supplied by the earth. By properly controlled the forces generated by this “electrodynamic” tether can be used to pull or push a spacecraft to act as brake or a booster. NASA plans to lasso energy from Earth’s atmosphere with a tether act as part of first demonstration of a propellant-free space propulsion system, potentially leading to a revolutionary space transportation system. Working with Earth’s magnetic field would benefit a number of spacecraft including the International Space Station. Tether propulsion requires no fuel. Is completely reusable and environmentally clean and provides all these features at low cost.


Added on: February 28th, 2012 by Afsal Meerankutty No Comments

Wireless transmission of electromagnetic radiation (communication signals) has become a popular method of transmitting RF signals such as cordless, wireless and cellular telephone signals, paper signals, two way radio signals, video conferencing signals and LAN signals indoors.

Indoor wireless transmission has the advantage that building in which transmission is taking place does not have to be filled with wires or cables that are equipped to carry a multitude of signals. Wires and signals are costly to install and may require expensive upgrades when their capacity is exceeded or when new technologies require different types of wires and cables than those already installed.

Traditional indoor wireless communication systems transmit and receive signals through the use of a network of transmitters, receivers and antennas that are placed throughout the interior of a building. Devices must be located such that signals must not be lost or signal strength may not get attenuated. Again a change in the existing architecture also affects the wireless transmission. Another challenge related to installation of wireless networks in buildings is the need to predict the RF propagation and coverage in the presence of complex combinations of shapes and materials in the buildings.

In general, the attenuation in buildings is larger than that in free space, requiring more cells and higher power to obtain wider coverage. Despite of all these, placement of antennas, receivers and antennas in an indoor environment is largely a process of trial and error. Hence there is need for a method and a system for efficiently transmitting RF and microwave signals indoors without having to install an extensive system of wires and cables inside the buildings.

This paper suggests an alternative method of distributing electromagnetic signals in buildings by the recognition that every building is equipped with an RF wave guide distribution system, the HVAC ducts. The use of HVAC ducts is also amenable to a systematic design procedure but should be significantly less expensive than other approaches since existing infrastructure is used and RF is distributed more efficiently.

Application of Shunt Power Filter

Added on: February 28th, 2012 by Afsal Meerankutty No Comments

In this paper, the implementation of a shunt active power filter with a small series reactor for a three-phase system is presented. The system consists of multiple non-linear loads, which are a combination of harmonic current sources and harmonic voltage sources, with significant unbalanced components. The filter consists of a three-phase current-controlled voltage source inverter (CC-VSI) with a filter inductance at the ac output and a dc-bus capacitor. The CC-VSI is operated to directly control the ac grid current to be sinusoidal and in phase with the grid voltage. The switching is controlled using ramp time current control, which is based on the concept of zero average current error. The simulation results indicate that the filter along with the series reactor is able to handle predominantly the harmonic voltage sources, as well as the unbalance, so that the grid currents are sinusoidal, in phase with the grid voltages and symmetrical.

Fluid Amplifiers

Added on: February 27th, 2012 by Afsal Meerankutty No Comments

When one stream of fluid is permitted to impinge on another, direction of flow changes and the tendency of a fluid to strike the wall also changes. This concept gives rise to a new engineering system known as ‘fluidics. The term fluidics is the contraction of the words fluid and logic. Tremendous progress has been made in last twenty years in design and application of fluidic devices.

The current interest in fluidics for logic and control function was launched by the U.S Army’sHarry Diamond Laboratories. In March 1960 this laboratories invented the first fluid amplifier. This work was later expanded through a series of research and development contracts and the work reported in this section was sponsored by the U.S Airforce.The environmental capability of fluidic devices permits direct measurement of required control parameters within the engine.

These devices are more economical, faster and smaller than hydraulic control elements employing moving parts such as valves etc. Fluid devices have no moving parts hence they are more reliable and have long life. Fluidics is now offering an alternative to some other devices being operated with the help of electronics. It can operate where electronic devices are unsatisfactory, such as high temperature, humidity, in presence of severe vibrations, in high fire risk or where ionizing radiations are presents.

Electro Chemical Machining

Added on: February 26th, 2012 by Afsal Meerankutty No Comments

Electro chemical machining (ECM) is the controlled removal of metal by anodic dissolution in an electrolytic medium in which the work piece is the anode & the tool is the cathode.
Working: Two electrodes are placed at a distance of about 0.5mm & immersed in an electrolyte, which is a solution of sodium chloride. When an electrical potential of about 20V is applied between the electrodes, the ions existing in the electrodes migrate toward the electrodes.

Positively charged ions are attracted towards the cathode & negatively charged towards the anode. This initiates the flow of current in the electrolyte. The electrolysis process that takes place at the cathode liberates hydroxyl ions & free hydrogen. The hydroxyl ion combines with the metal ions of anode to form insoluble metal hydroxides &the material is thus removed from the anode. This process continues and the tool reproduces its shape in the work piece (anode). The high current densities promote rapid generation of metal hydroxides and gas bubble in the small spacing between the electrodes. These become a barrier to the electrolyzing current after a few seconds. To maintain a continuous high density current, these products have to be removed continuously. This is achieved by circulating the electrolyte at high velocity through the gap between the electrodes. It is also to be noted that the machining gap size increases. Therefore to maintain a constant gap the cathode should be advanced towards the anode at the same rate at which the material is removed.

Expert Systems

Added on: February 26th, 2012 by Afsal Meerankutty No Comments

An intelligent fault diagnosis and operator support system targeting in the safer operation of generators and distribution substations in power plants is introduced in this paper. Based on Expert Systems (ES) technology it incorporates a number of rules for the real time state estimation of the generator electrical part and the distribution substation topology. Within every sampling cycle the estimated state is being compared to an a priori state formed by measurements and digital signaling coming from current and voltage transformers as well as the existing electronic protection equipment. Whenever a conflict between the estimated and measured state arises, a set of heuristic rules is activated for the fault scenario inference and report. An included SCADA helps operators in the fast processing of large amounts of data, due to the user-friendly graphical representation of the monitored system. Enhanced with many heuristic rules, being a knowledge based system, the proposed system goes beyond imitation of expert operators’ knowledge, being able to inference fault scenarios concerning even components like the power electronic circuits of generator excitation system. For example, abnormal measurements on generator’s terminals can activate rules that will generate fault hypothesis possibly related to an excitation thyristors abnormal switching operation.

Quantum Mirage

Added on: February 26th, 2012 by Afsal Meerankutty No Comments

Since it first appeared on the cover of Nature in February 2000, the quantum mirage” has featured on posters, calendars, websites and the covers of various books and magazines. The image – which was obtained using a scanning tunnelling microscope – shows the electronic wavefunctions inside an elliptical “quantum corral” made of cobalt atoms on a copper surface. It was created by Hari Manoharan, Christopher Lutz and Don Eigler of the IBM Almaden Research Center in California. In 1990, working with Erhard Schweizer, Eiger spelt out the letters “IBM” using 35 xenon atoms. And three years later, working with Lutz and Michael Crommie, he released the first images of the “quantum corral”, which have also been reproduced in numerous places.

The quantum mirage uses the wave nature of electrons to move the information, instead of a wire, so it has the potential to enable data transfer within future nano-scale electronic circuits so small that conventional wires do not work. It will be years before this technology becomes practical, but it could eventually yield computers that are many orders of magnitude smaller, faster, and less power-hungry than anything we can conceive today.

Mine Detection Using Radar Bullets

Added on: February 26th, 2012 by Afsal Meerankutty No Comments

Land mines are a case of serious threats to the life of civilians, especially in mine-affected countries like Afghanistan and Iraq .The mines which are implanted during the war time may remain undetected for several decades and may suddenly be activated after that. There are several methods for detection of land mines, such as metal detection and explosive detection. These ways of detection are dangerous because they are done very close to the mine.

A safe method for detecting land mines is “mine detection using radar bullets”. As the name suggests detection is done using Radar Bullets and hence can be done further away from the mine. Detection is usually done from helicopters. Researchers are being conducted to overcome certain inefficiencies of this method.

Microwave Superconductivity

Added on: February 25th, 2012 by Afsal Meerankutty No Comments

Superconductivity is a phenomenon occurring in certain materials generally at very low temperatures, characterized by exactly zero electrical resistance and the exclusion of the interior magnetic field (the Meissner effect). It was discovered by Heike Kamerlingh Onnes in 1911. Applying the principle of Superconductivity in microwave and millimeter-wave (mm-wave) regions, components with superior performance can be fabricated. Major problem during the earlier days was the that the cryogenic burden has been perceived as too great compared to the performance advantage that could be realized. There were very specialized applications, such as low-noise microwave and mm-wave mixers and detectors, for the highly demanding radio astronomy applications where the performance gained was worth the effort and complexity. With the discovery of high temperature superconductors like copper oxide, rapid progress was made in the field of microwave superconductivity.

This topic describes the properties of superconductivity that can be exploited in microwave and mm-wave technologies to yield components with appreciable performance enhancement over conventional systems. Superconducting signal transmission lines can yield low attenuation, zero-dispersion signal transmission behavior for signals with frequency components less than about one tenth the superconducting energy gap. No other known microwave device technology can provide a similar behavior. Superconductors have also been used to make high speed digital circuits, josephsons junction and RF and microwave filters for mobile phone base stations.

Beamed Power Transmission

Added on: February 24th, 2012 by Afsal Meerankutty No Comments

The desire of the modern man for more and more amenities and sophistication led to the unscrupulous exploitation of natural treasure. Though nature has provided abundant source of resources. It is not unlimited. Hence the exhaustion of the natural resources is eminent. The only exception to this is sunlight.

Scientist who had understood the naked truth had thought of exploiting the solar energy and started experimenting in this direction even from 1970. But the progress was very slow. Much headway is yet to be made in this direction. However as the impotents source of non-conventional energy and due to the limited source of conventional energy emphasis has given for the better utilization of solar energy.

But the application of solar cell, photovoltaic cell etc, we are able to concert only a small percentage of solar energy into electrical energy. But by using beamed power transmission from solar power satellite we can envisage a higher percentage of conversion. By beamed power transmission, we can extend the present system of two dimensional transmission network to three dimensional, if does not have any environmental problem as well.

Maglev Train

Added on: February 23rd, 2012 by Afsal Meerankutty 1 Comment

Magnetic levitation is the latest in transportation technology and has been the interest of many countries around the world. The idea has been around since 1904 when Robert Goddard, an American Rocket scientist, created a theory that trains could be lifted off the tracks by the use of electromagnetic rails. Many assumptions and ideas were brought about throughout the following years, but it was not until the 1970’s that Japan and Germany showed interest in it and began researching and designing.

The motion of the Maglev train is based purely on magnetism and magnetic fields. This magnetic field is produced by using high-powered electromagnets. By using magnetic fields, the Maglev train can be levitated above its track, or guideway, and propelled forward. Wheels, contact with the track, and moving parts are eliminated on the Maglev train, allowing the Maglev train to essentially move on air without friction.

Maglev can be used for both low and high speed transportation. The low speed Maglev is used for short distance travel. Birmingham, England used this low speed transportation between the years of 1984 and 1995. However, engineers are more interested in creating the high-speed Maglev vehicles. The higher speed vehicle can travel at speeds of nearly 343mph or 552 km/h. Magnetic Levitation mainly uses two different types of suspension, which are Electromagnetic Suspension and Electrodynamic Suspension. However, a third suspension system (Intuctrack) has recently been developed and is in the research and design phase. These suspension systems are what keep the train levitated off the track.

Heat Pipe

Added on: February 22nd, 2012 by Afsal Meerankutty No Comments

A heat pipe is a simple device that can quickly transfer heat from one point to another. They are often referred to as the “superconductors” of heat as they possess an extra ordinary heat transfer capacity & rate with almost no heat loss.

The development of the heat pipe originally started with Angier March Perkins who worked initially with the concept of the working fluid only in one phase (he took out a patent in 1839 on the hermetic tube boiler which works on this principle). Jacob Perkins (descendant of Angier March) patented the Perkins Tube in 1936 and they became widespread for use in locomotive boilers and baking ovens. The Perkins Tube was a system in which a long and twisted tube passed over an evaporator and a condenser, which caused the water within the tube to operate in two phases. Although these early designs for heat transfer systems relied on gravity to return the liquid to the evaporator (later called a thermosyphon), the Perkins Tube was the jumping off point for the development of the modern heat pipe.

The concept of the modern heat pipe, which relied on a wicking system to transport the liquid against gravity and up to the condenser, was put forward by R.S. Gaugler of the General Motors Corporation. According to his patent in 1944, Gaugler described how his heat pipe would be applied to refrigeration systems. Heat pipe research became popular after that and many industries and labs including Los Alamos, RCA, the Joint Nuclear Research Centre in Italy, began to apply heat pipe technology in their fields. By 1969, there was a vast amount of interest on the part of NASA, Hughes, the European Space Agency, and other aircraft companies in regulating the temperature of a spacecraft and how that could be done with the help of heat pipes. There has been extensive research done to date regarding specific heat transfer characteristics, in addition to the analysis of various material properties and geometries.

Tunable Spiral Inductors

Added on: February 20th, 2012 by Afsal Meerankutty No Comments

A tunable micro-electromechanical systems integrated inductor with a large-displacement electro-thermal actuator is discussed here. Based on a transformer configuration, the inductance of a spiral inductor is tuned by controlling the relative position of a magnetically coupled short-circuited loop. Theoretical studies are backed by a variety of fabricated and measured tunable inductors that show a 2 : 1 inductance tuning ratio over a wide frequency range of approximately 25 GHz. In addition, the maximum and minimum quality factors of the tunable inductor are measured to be 26 and 10 which is high compared to previous designs. They can considerably extend the tuning capabilities of critical reconfigurable circuits such as tunable impedance matching circuits, phase shifters voltage controlled oscillators, and low noise amplifiers.

Flexible AC Transmission Systems

Added on: February 19th, 2012 by Afsal Meerankutty No Comments

The rapid development of power electronics technology provides exciting opportunities to develop new power system equipment for better utilization of existing systems. Such as enhancing the security, capacity and flexibility of power transmission systems. FACTS solutions enable power grid owners to increase existing transmission network capacity while maintaining or improving the operating margins necessary for grid stability. Supply of reliable, high-quality electrical energy at a reasonable cost is at the heart of the nation’s economy. The electric power system is one of the nation’s important infrastructures, and the infrastructure most closely tied with the gross domestic product. In view of changes in both the operating and business sector of the electric utility industry. These changes have been mandated by provisions of the Energy Policy Act of 1992, and electric utilities to provide open access to the transmission system.

Several advanced methods are developed for maintaining a high degree of power quality and reliability under a deregulated environment. At the distribution level, flexible control strategies involve computerized automation of system control devices such as capacitor banks, under load tap changing transformers (Ultc’s) and voltage regulators. In the transmission system, a new method of achieving this control is through the use of power electronics based Flexible AC Transmission System (FACTS) devices. This paper provides a comprehensive guide to FACTS, covering all the major aspects in research and development of FACTS technologies. Various real-world applications are also included to demonstrate the issues and benefits of applying FACTS.The objective of this project is to create a multi-institutional power curriculum to address this new environment and technologies.


Added on: February 13th, 2012 by Afsal Meerankutty No Comments

The rate of rise of power utility in a country represents its development in any field” necessity is the mother of invention “.so, efficient and reliable power supply is the major requirement of any power supply system. as in many other areas, the computer applications in electrical power system have grown tremendously over the last several decades ,penetrating apparently all aspects of electrical power systems including operational planning ,energy management systems, automation of power generation ,transmission and distribution, protection relaying, etc. a system used to monitor and control equipment and process is Called SCADA.SCADA system is the one of the applications of it.

The present paper explains about the whole SCADA system, its hardware components, software components and its application programs. in hardware components its field instrumentation, remote stations, communication network, central monitoring station are explained. in software components data acquisition and processing ,control, alarm handling, logging and archiving, automated mapping and facility management etc.are considered. and very clearly the appliCation programs like load shedding ,load balancing, remote metering ,maintain good voltage profile, maintain, maps, fuse Call off operations, energy accounting, etc. are emphasized.

Microbial Fuel Cells

Added on: February 9th, 2012 by Afsal Meerankutty No Comments

In an era of climate change, alternate energy sources are desired to replace oil and carbon resources. Subsequently, climate change effects in some areas and the increasing production of biofuels are also putting pressure on available water resources. Microbial Fuel Cells have the potential to simultaneously treat wastewater for reuse and to generate electricity; thereby producing two increasingly scarce resources.

While the Microbial Fuel Cell has generated interest in the wastewater treatment field, knowledge is still limited and many fundamental and technical problems remain to be solved Microbial fuel cell technology represents a new form of renewable energy by generating electricity from what would otherwise be considered waste, such as industrial wastes or waste water etc. A microbial fuel cell [Microbial Fuel Cell] is a biological reactor that turns chemical energy present in the bonds of organic compounds into electric energy, through the reactions of microorganism in aerobic conditions.

Flywheel Energy Storage

Added on: January 26th, 2012 by Afsal Meerankutty 1 Comment

Energy Storage is becoming increasingly important with the advent of individual electronic devices and the rising need to accommodate a greater population which relies on these devices. A flywheel is simple form of mechanical (kinetic) energy storage. Energy is stored by causing a disk to spin on its axis. Flywheels are one of the most promising technologies for replacing conventional lead acid batteries as energy storage systems for a variety of applications including automobiles, economical rural electrification systems, and stand-alone, remote power units commonly used in the telecommunications industry.

Commercially available Flywheel Energy Storage (FES) Systems are used for small uninterpretable power systems. More recently, the flywheel has regained consideration as a viable means of supporting a critical load during mains power interruption, due to the lower capital expense and extended run time now available from many systems, as well as continued customer dissatisfaction with traditional electrochemical energy storage.

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