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How about elastic gadgets that one can wear? Sounds amazing right? It would be feasible in the near future.

Elastic technologies could make flexible garments and robotic components that human might wear to interact with computers and healing purposes in case of any health problems.

Rebecca Kramer, an assistant Professor of Mechanical Engineering at “Purdue University”, said that new techniques manufacturing such devices must be developed before making it  commercial. She further said that we want to create stretchable electronics that might be compatible with soft machines like the robots that we have seen in many science movies, when Hero pass through narrow and irregular spaces with ease with the help of tech wearable gadgets. This wearable stuff doesn’t restrict motion hence the person can move without any problem.

On an interview, she also said, “Conductors made from liquid metal can stretch and deform without breaking.” It’s worth noting that scientist have already made closely related components that we are using already commercially like flexible solar panels and computer accessories.

Recently a technique was developed, that focus making components by using a mixture of alloys in an inkjet printer. That means, it use liquid metal instead of ink and can be printed according to the need on a flexible fabric or elastic material.

The printing ink is made by dispersing the metal in a non-metallic solvent. This is done by the use of ultrasound. The sound breaks up metal into nanoparticle. The good news is that it is fully compatible with the inkjet printer. The nanoparticles thus rejoined by applying light pressure. This is crucial as the metal previously is coated with oxidized gallium and  acting as a skin,  preventing electrical conductivity.

The only drawback is, it’s fragile and breaks on applying pressure resulting into uniform flat film. Kramer said, “we can do this either by stamping or by dragging something across the surface, such as sharp edge of a silicon tip.”

published in “Science Daily”

A research paper about the method will appear on April 18 in the journal Advanced Materials. The paper generally introduces the method, called mechanically sintered gallium-indium nanoparticles, and describes research leading up to the project. It was authored by postdoctoral researcher John William Boley, graduate student Edward L. White and Kramer.

It would be astonishing to see how they are going to make I happen and we as a user be using it.

Camera telling object information
Image: Unispectral/Tel Aviv University



We have seen in many Science fiction movies when a character with its Hi-fi device scans an object and instantly get all he chemical and physical details of it.

We got curious many times about what an object is made of .The next thing we do is Google it, to satisfy the curiosity. But how would it be if you get such information just by clicking a picture and getting all the feedback for that object or thing you have captured by a mobile camera? It would be amazing, right? Well, you are going to get such things in the near future.

Electrical engineers from Tel Aviv University have invented such device that can be integrated with smart phone cameras. It is capable of detecting the chemical composition of an object or a substance like fluid by simply taking a picture or deciphering a video of it.

It uses Hyperspectral Imaging which is collecting and processing information from across the electromagnetic spectrum. Our satellite utilizes this technology to detect the nutrient and composition of soil in exo-planet. It’s worth noting that this type of imaging can be done with large sophisticated cameras but researchers say that, they have developed a new patented optical component. It can be integrated with the camera of a smartphone of a user.

They said that their optical component primarily based on microelectromechanical or MEMS Technology, relating to small mechanical machines having less than a millimeter in size .These miniature machines consists of primarily a microprocessor to process data, sensors and simple components.

They claim the device can be mass produced and is compatible with all the standard smartphone cameras available in the market. “We predict hyperspectral imaging will play a major role in consumer electronics, the automotive industry, biotechnology, and homeland security,” said lead inventor, David Mendlovic, in a press release.

This sounds easy in theory but they will need to pair up whole information collected from the image with a database containing immense information on the hyperspectral signature of a wide range of different chemicals.

Last month , at the Mobile world Congress in Bacelona, the basic system was demonstrated by the developers. Now they are working on a functional prototype. They say it would be ready by june this year.

One of the largest Indian Engineering group “Tata Group” is backing them with the funds. It would be interesting to see the marvel of Engineering.

Tell us what you think about it by commenting below.


Source : Science Alert

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Pyroelectricity Definition

 It is a Greek word derived, means electricity generated by heat.

Certain materials have the ability to produce temporary voltage when they are heated or cooled.  The change in temperature modifies the position of the atoms slightly within the crystal structure because polarization changes within the material. The change in polarization give rise the potential difference across the material and hence the voltage.

The pyro-electric voltage gradually vanishes due to leakage current. This can happen when the electrons move through the crystal, or moving of the ions through the air.

Pyroelectricity Vs Thermoelectricity Vs Ferroelectricity

Pyroelectricity is different from the thermoelectricity as the whole crystal when induced with the temperature change, conjures the polarity in the crystal and hence the potential difference temporarily.

 While in case of thermo electricity the two dissimilar materials are joined and the joining ends when kept in at a temperature difference, causes a permanent voltage as long as the temperature is maintained across the ends.

Ferroelectricity is the intrinsic property of some materials that have a spontaneous electric polarization that can be reversed by the application of an external electric field. The term is normally used analogous to ferromagnetism, in which a material exhibits a permanent magnetic moment.

Pyroelectric Effect and Pyroelectricity Explanation-

 It can be visualized as sort of one side of a triangle, where each side portrays energy states in the crystal viz. kinetic, electrical and thermal energy.  The side between the electrical and thermal corners shows the pyroelectric effect and generates no kinetic energy. The side between kinetic and electrical corners exhibits the piezoelectric effect and produces no heat.

Artificial materials have been developed by the engineers. The effect was discovered in the mineral Tourmaline for the first time.  You would be surprised that pyroelectric effect is present in our body in both bones and tendons. The pyroelectric charge develops on the opposite faces of asymmetric crystals in minerals.

The direction of propagation of the electric charge is generally constant throughout the pyroelectric material. Though in some materials this direction can be changed by nearby electric fields. These materials are said to exhibit ferroelectricity. All pyroelectric materials are piezoelectric and the two properties are closely related. It is worth noting that some piezoelectric materials have crystal symmetry that does not permit pyroelectricity.

A very small temperature change can produce an electric potential difference due to a material’s pyroelectricity. Passive infrared sensors are often designed around pyroelectric material as the heat of a human or animal from several feet away are enough to produce a difference in charge.

 pyroelectric crystals, classes and piezoelectricity

All kind of crystals that has been discovered can be divided into 32 crystal classes. 21 crystal are non centrosymmetric (does not have the Centre of symmetry) out of 32 crystal structures.  20 crystals out of these 21 exhibits direct piezoelectricity.

10 crystals out of 20 are classes re polar that means they bears a spontaneous polarization, shows piezoelectricity and have a dipole in their unit cell. If somehow the dipole in the unit cell is reversed by the utilization of electric fields then that crystal said to be ferroelectric in nature. We all know that when an external electric field is applied to dielectric material it develops a dielectric polarization i.e. the electrostatics. However if the material has such natural charge separation capability even in the absence of electric fields it is called a polar material.

Only ten crystals out of 32 are grouped as polar crystal and all the polar crystals are pyroelectric. Hence these 10 polar classes are sometimes called as pyroelectric classes.

This property of the pyroelectricity is the measured change in the net polarization and this is proportional to the change in temperature or temperature gradient.

The net pyroelectric coefficient at constant stress is the sum total of pyroelectric coefficients at constant strain and the piezoelectric induced from thermal expansion. Contribution from thermal expansion is called the secondary pyroelectric effect while pyroelectric strain at constant strain is called primary piezoelectric effect.

Under normal conditions, even the polar substances do not exhibit a net dipole moment. As a result there are no dipole equivalents of bar magnets. This is because the intrinsic dipole moment is neutralized by free electric charge that builds up on the surface due to either outer ambient atmosphere or by the internal conduction. Polar crystals only display their nature when altered in some fashion that momentarily upsets the balance with the compensating surface charge.

This article is in continuation with our previous article Stirling Engine Project Idea. In this article we will discuss various types of Stirling engines and their working in detail. Sterling engines work on simple principle of  temperature difference where compression and expansion of gases produces useful work. Even after the advancement of Internal Combustion engines, Stirling engines are still used in different industrial applications for they are more efficient. Working model of Stirling engines can easily be made hence it can be very good Mechanical Engineering Project Idea for you.

Types Of Stirling Engine:

Alfa type Stirling engine:-

Alfa stirling engine consists of two cylinders .

One cylinder (expansion cylinder) is kept at high temperature while another (compression cylinder) at low and the passage between the two cylinder contains the regenerative fluid (gas) working of the Alfa type Stirling engine as discussed above that it contains two cylinders one is hot and other cold.

The hot cylinder is fitted inside the high temperature heat exchanger and colder one inside the low temperature heat exchanger. This type of heat engines has a high power to volume ratio though has technical problems because of high temperature of hot piston and durability of its seals. Though there is some additional dead space inside the cylinder to reduce this problem.

  1. Shown in the diagram, nearly all the working gas is in contact with the hot cylinder walls. The gas has been heated and therefore expansion takes place which has pushed the hot piston to the bottom. The expansion continues in the other cylinder (cold cylinder), which is 90 degree behind the hot piston in its cycle thus extracting more work from the hot gas.
  2. Now in the second diagram, the gas is now at its maximum volume. The hot cylinder begins to push most of the gas into the cold cylinder, where it cools and the pressure drops considerably.
  3. As you can see in the third diagram, almost all the gas is in the cold cylinder and cooling continues. The cold piston which is powered by the flywheel momentum compresses the remaining part of the gas.
  4. Here in the fourth diagram, you can see the gas reaches its minimum volume and now it will expand in the hot cylinder where it is heated once more thus driving the hot piston in its power stroke.

This completes the whole working of the Alfa type Stirling engine. Now we come to beta type stirling engines.


Beta type stirling engine:

Beta type stirling engine consists of only one cylinder with hot and cold ends, a loosely fitted displacer which shunts the air (working gas) between hot and cold end and a power piston at the end of the cylinder which drives the flywheel. The flywheel is connected to the piston with help of connecting links.

A cross section of a beta stirling engine design is shown in the diagram. Different parts includes-

  1. hot cylinder wall
  2. Cold cylinder wall
  3. Coolant inlet and outlet pipe
  4. Thermal insulation which separates the two cylinder ends
  5. Displacer piston
  6. A power piston
  7. Flywheel
  8. Linkages it removes the technical problems of hot moving seals unlike the Alfa type. Displacer and the power piston arranged in the same shaft. The displacer in this case does not extract power from the expanding gas but serves to shuttle the working gas between hot and cold ends.
  1. The power piston has compressed the working fluid, the displacer piston has moved so that most of the gas gets closer to the hot heat exchanger.
  2. The heated gas increases the pressure inside the cylinder and pushes the power piston to the farthest limit of the power stroke.
  3. The displacer now moves and pushes the gas to the cold end of the cylinder.
  4. Finally the cooled gas is compressed by the flywheel momentum and it takes less energy as its pressure drops when it is cooled.

As we have discussed earlier that it is a closed cycle process which means the heat driving it must be transmitted from a heat source to the working fluid and eventually to the sink. The heat source for it can come from burning of fuel, waste combustible products, landfill gases etc as it does not comes in contact with internal parts. Other sources can include concentrated solar energy, geothermal energy nuclear energy, waste heat and bio-energy which are in abundance in nature.

Gamma Stirling Engines:

Gamma Stirling engines are similar to beta engines i.e these are also displacement type but in this, the power piston is mounted in separate cylinder along side displacer piston cylinder but still connected to same flywheel.

This ends our discussion on sterling engines. Check out various Mechanical engineering projects ideas based on Stirling engines. If you want further information on any project, let us know.



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In this article we will provide you a thesis report on Whittmore-Petrenko Proving ring or simply proving ring. In this project on proving ring we will provide you background history on proving ring, types of rings, materials required, design, construction and working of  Proving ring. The project covers Strength of materi

als among various other subjects of mechanical engineering.


Proving ring is a force transducer concept designed, analyzed and developed to be used in laboratory experiments to measure forces. The elastic behavior of the proving ring was analyzed using Castigliano’s second theorem and the results were found to be about 1% accurate.

The proving ring is a metal ring equipped with means of measuring deflection when under load. The concept of proving ring was created originally by Whittmore and Petrenko at the US National Bureau of standards.


Force transducers are commonly used in engineering applications like weighing scales, verification of material testing machine, thrust measurement etc. Ring shaped transducers provide an ease in manufacturing and are widely used for the measurement of force.

The proving ring is a elastic metal ring with a means of measuring deflection when it is under load. It is used to measure force. The ring is currently used in laboratory exercises and in research projects in fluid mechanics.

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In our previous article we read about how car ignition system works and also the complete working of spark plugs. In this article we are going to discover various types of spark plugs available and their classification in detail. The design of spark plug is based on the type of engine used. Different designed spark plugs are used to suit the following parameters:-

  • loading and speed range of an engine
  • its combustion chamber design
  • varying fuel mixture strength
  • compression ratio and
  • operating temperatures
  1. Long reach spark plug

    It is used where cylinder -head section is very deep (i.e. thickness is large) while in thinner head such plug would project too far into the combustion chamber and will have a short life.1

  2. Short reach spark plug

    As discussed in 1, it is used in thin cylinder- head cross section. In deeper head, its electrodes would lag behind thus producing inappropriate spark resulting in incomplete combustion of fuel.Page 85 (2)-001

  3. Tapered-shoulder plug

    This type of design is incorporated where no gasket is used. Its tapered conical head is tightened into the cylinder head removing the need for gasket.

  4. Cold plug

    It has a short insulator(less ceramic covering) i.e. more contact area with the metal part of the plug and cools faster thus preventing pre-ignition through overheating & making it apt for high performance engines.Page 85 (2)-005

  5. Hot plug

    In contrary to cold plug it has long insulator i.e. less contact area with the metal part (having more ceramic covering), has a long heat flow which makes it apt for low performance engines. It also burns off any deposits on the plug.Page 85 (2)-006

  6. Side gap plug

    As shown in the picture, it has the side gap between the electrodes which increases horsepower by enshrouding the spark. It allows the flame created to propagate faster resulting in proper combustion of the air fuel mixture. It is often used in highly tuned engines.

  7. Three gap

    A|three gap Plug-as the name suggests it has three gaps produced by the three earthed electrode (one is hidden behind in the picture) to give longer plug life.

In normal cars copper cored spark plugs are used. The reason behind using copper core is high conductivity but because of its inability to have a longer life makes it less usable (though some racers prefers it and replaces frequently). In custom engines and high rev engines, iridium and platinum alloy spark plugs are used.

These plugs have good longevity and durability. These are apt for high compression engines (turbocharged engines). The diameter of the central electrodes vary between 0.4 mm (Iridium) to 0.7 mm (platinum). These spark plugs with super fine tips (greater ignitability) exhibited its importance in high performance engines.

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You might have encountered a situation when you were ready to go for an urgent work but your car fails to start. No matter how many times you turn the keys, you are unable to hear that vroom sound you love to hear from your car. Upon calling a mechanic, you come to know that there is some fault in the ignition system of the car. The obvious question that arises in mind is how ignition system works? And what are those unfamiliar components used in ignition system? Why it’s not simple to burn the fuel inside engine? In this article we are going to cover the basic details of ignition system’s working.

All right let’s start with the basic introduction and detailed working of car ignition system. Well ignition system is the combination of

  • Battery
  • Induction coil
  • distributor
  • high voltage conduction coil winding coil
  • spark plugs etc

These collectively work to create a spark inside the combustion chamber.

It’s quite important to know at this point that a car battery produces 6 to 12 volts but a voltage of around 40,000 to 100,000 is required to generate a spark from spark plug. So how the spark plug manages to produce that much voltage?  The principle behind this phenomenon is that when electricity flows in a coil of wire, a magnetic field is produced and energy is stored. When the current stops, magnetic field breaks down resulting into a voltage spike in the coil of wire within the field lines of force. This   process takes place in the induction coil. Let’s get into more details for better understanding.

Induction Coil

Induction coil consists of

  • Soft iron core which concentrates the magnetic field.
  • Thick wire coil for primary winding.
  • Thin wire coil for secondary winding.

The primary coils(primary winding) has  few 100 turns around the soft iron core acting as low voltage part which is connected to the battery while secondary coil(secondary winding) can have several thousand turns perhaps up to fifteen hundred meters in all, acting as high voltage part. It’s kind of a mini transformer.

Working of induction coil

When the ignition key (car key) is turned on then current from the battery flows through one terminal of the induction coil to primary winding and then to contact- breaker points in the distributor. When the contact breaker points are closed, current propagates through them, turning the primary coil and iron coil into electromagnet while creating a magnetic field. The current then completes its circuit through the body of the car and back to the battery.

Now at this stage if the breaker points open, the circuit is momentarily interrupted to generate high-voltage current in the secondary winding which is then fed through the distributor to spark plug to generate spark in the combustion chamber.


The main function of distributor is to distribute the high voltage from the induction coil to the spark plug in the appropriate cylinder. The timing is very crucial for the engine to perform well. It consists of a rotor which is connected to the coil; the rotor rotates inside the cap and while rotating it transmits high voltage to the cap at specific interval. This happens because its tip comes close to the contact points on the cap. Distributor has one contact point per cylinder. This transmitting (in the form of arc as it never touches each other) of high voltage from rotor to contact point is tuned up perfectly with the power stroke in the cylinder. It contains a condenser (capacitor) which prevents arc thus heating across the contacts point.

The other function of the distributor is to break the current of the coil with the help of contact breaker.

Now let us take a look at how arc is controlled in a distributor. This is done with the help of another part housed in distributor called contact breaker.

Contact Breaker

 Contact breaker is housed with distributor along with a condenser (capacitor). The high voltage produced in primary windings due to magnetic fields causes an arc across the opening contact breaker points. To avoid burning and pitting a condenser is added to suppress the arcing. The capacitor also acts as reservoir for electrical energy. This energy flows back through primary windingand thus speeding the collapse of magnetic field and increasing voltage in secondary winding.

The voltage thus produced travels through high tension wires to spark plug

(continue reading……).

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In some of our previous articles we talked about Stirling engines, their working, types and many project ideas based on Stirling engines. In this article we are going to learn about yet another type of Stirling engine known as Free Piston Engine.

A free piston engine? This must be the obvious question which must be coming  to your mind but yes, you read it correct. Ok let’s go into its detailed configuration and working with implications. A free piston engine is simply the Stirling engine where a diaphragm or liquid is used instead of the power piston unlike the internal combustion engine installed in your car or bike.

Working of Free Piston Engine Project

The basic steps of working of free piston are as follows:-

  • Hot gases as always expanded due to heating and push the power piston outward thus doing work and there is no role of gravity in the cycle.
  • The volume of the gases inside the engine increases and therefore the pressure reduces, which causes pressure gradient (difference) across the displacer towards the hot end. During the motion of the displacer, the piston almost remains stationary and hence the gas volume is constant. It results in the constant volume cooling process which reduces the pressure of the gas.
  • The reduced pressure now holds the outward motion of the piston and it begins to accelerate towards the hot end again and by its own inertia, compresses the cold gas which is cooled now residing in the cold space.
  • with the increase in pressure, an optimum point is reached where the pressure differential across the displacer rod becomes sufficient enough to begin to push the displacer rod towards the piston, collapsing the cold space and transferring the cold, compressed gas towards the hot side in an almost constant process. After arrival of the gas at hot side, the pressure increases and begins to move the piston outwards to initiate the expansion.

W.T. Beale was the one who invented this free piston version of Stirling engine to overcome the difficulty of lubricating the crank mechanism. There can be many project ideas based on free piston engine. If you want to know more about any project, leave your comments below. We would love to hear from you.

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Welding advantages and safety apparel
A welder using Electric Arc Welding wearing safety equipment

A Short Note On Welding 

Presently, many process of welding have been developed and there is probably no industry which is not using welding in any form for the fabrication of their products. Researches have led to join dissimilar metals also by the mean of welding. The beauty of welding is that welded joint can have more than 100 percent strength than the single unit. Welding is easier to joint different parts of the products compared to others.

Welding nowadays is extensively used in the fields like:

  • Automobile industry
  • Aircraft machine frames
  •  Structural work
  •  Tanks
  •  Machine repair work
  • Ship  building
  •  Pipe line fabrication
  •  In thermal power plants
  •  Fabrication of metal structures and refineries, etc.


Welding are basically classified as solid phase welding and fusion welding:

Fusion welding:  is the coalescence of two materials by the application of heat. The two joining parts are paced together; a filler material is melt by the introduction of heat and solidifies upon cooling thus joining the part. The heat can be produced by myriad number of ways.

Solid phase welding: are produced by bringing the clean faces of component into intimate contact to produce metallic bond with or without the application of heat but the application of pressure is very essential to induce plastic flow.


Advantages of welding over other type of joints:

  • Buildings , bridges and structures can be built lighter and thus higher due to reduction in weight
  • These are cheap also due to reduction in weight and material cost. Additional joints strength can be obtained by using considerably smaller structural members. Joints are compact and do not require additional plates as in case of riveted joints.
  • Welded joints have high corrosion resistance compared to bolted and riveted joints.
  • Welded joints are fluid tight for tanks and vessels.
  • Welded structures can be altered easily and  economically
  • Many different types of joints are possible in welded joints.


Additional Points Worth Pondering:

Welding radiations

Welding process produces rays of longer wavelengths compared to X –rays or gamma rays. These can be broken into visible light rays, infra rays, ultraviolet rays. Visible light can induce eye strain and general discomfort. Ultraviolet rays are invisible and can cause burns on unprotected skin. Infra-red rays have longer wavelength and these produce heat when they strike and absorbed by the surface. Prolonged exposure can cause skin burns.

Protection of the welder from the process

Welders have to protect themselves while welding. They have to prevent them from sparks and hot molten metal, UV rays, infra-red rays, visible light rays, welding fumes and other hazards.

welder with safety equipment animated
Safety is Important!

A welder should wear welding jacket or sleeves made of leather or denim. Leather sleeves, high top boots. Clothes should be fit tight enough so that no bare skin is exposed to sparks or ultra violet rays. Safety glasses or glasses fitted with side shields must be worn.

Welded joints remain in tension

The weld filler material is in liquid state and it undergoes both solidification shrinkage and contraction during cooling. Parent metal being colder and larger in mass inhibits the contraction of the weld material putting weld in tension.

Relieving the tension by hammering

The welder peen the weld joint with the hammer while doing so introduces the stress and thus build up tension in the weld is relieved. Surface oxides and residual flux present on weld surface also get removed. For uniform cleaning and stress removal, shot blasting is preferred.








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Inkjet Printer  would create Electronic Devices 

Technology has reached way far from the last few decades and still enthralling people with the intriguing inventions and discoveries day by day. I have come up with the new technology news and a potential project idea for the engineering students.

What if I say that this technology is also going to amaze you again. Yes, it is. This latest technology allows printing  electronic devices the same way as inkjet printer prints a photo or a document. It seems unusual and impossible but it is true.silicon wafers

The researchers have used the printing method to build a portable X-ray imager and small mechanical devices. This is one of the illustrations how far a technology can go. It is time consuming and costly to produce silicon wafers so it would aid in that regard.

How it is done?

The conventional photolithography method is complex. The method includes depositing the layer of the material and stencil like material is placed over it. A beam of ultraviolet light is fed upon it and the exposed material is etched away. The process is then repeated to make the patterns required to form electronic devices and circuits.

In the past few years, researchers have been developing the methods to deposit patterns of metals, semiconductors and material directly like a printer deposits patters of ink. The materials are dissolved in a liquid solvent (special solution), which can then be printed on a variety of substrates, such as plastic, paper and even fabric. The material remains after the ink dries.

To illustrate this technology the researchers built a digital X-ray sensor. By adopting the technique of printing the researchers fabricated flexible X-ray arrays plastic films that are much portable than the huge frightening gadgets at our dentist’s clinic. The devices made out of it can be used by the doctors easily, serve security scanners or even assist soldiers in identifying bombs in battle fields.inkject printer printing electronic  devices

The researchers are also grafting on an actuator, which is as simple mechanical device. The printable actuator is based on solution –processed organic materials and behaves like “artificial muscles” unlike the typical actuators. Researchers have not forged particular uses for such an actuator. But it could be used in conjunction with photo imagers to make adaptive optical parts that tune up the focal distance and to make moving errors that redirects the beam of light.

This technique would not create high end sophisticated silicon chips for the gadgets like phone and computers but it would ensure more high volume, simple but very useful systems. In future “you might be able to print sensors onto clothing or some other device attached to skin to monitor vital signs –and alert a doctor in case of an emergency”, researchers said. There researchers also, have been printing devices in making flexing solar cells.

It would be great fun to wear jackets with the flexible solar panel and produce electricity when in need. Charging a phone at home would no longer require as we can charge it anytime anywhere.

If you get one, it would be easier for you to make static projects too and somehow solve your problems also.