Applications of Nanotechnology in the defense and military field

In this video we are going to explain about nanotechnology applications in the defense and military feild in Telugu

Sensors for Chemical and Biological Warfare Agents

The detection of chemical and biological warfare agents, radiological agents, and other hazardous vapors has significant import for both the military and homeland security efforts. Small, lightweight, portable, and high sensitive sensors based on nanomaterials are currently being developed and evaluated.

Using Gold Nanoparticles in Sensors for Chemical and Biological Warfare Agents - What This Process Involves

Gold nanoparticles have been investigated for use in sensors for both chemical and biological warfare agents. In one example, ‘chemi-resistors’ comprised of thin films of nanogold particles encapsulated in monomolecular layers of fictionalized alkanethiols deposited on interdigitated microelectrodes reversibly absorb vapors. Monolayer swelling or dielectric alteration in the thin film caused by absorption of the vapor molecules causes a small current. The system appears to have minimal water sensitivity, but can detect harmful vapors down to the parts per billion level or lower. Selectivity of the sensors can be tailored by changing the structure and functionality of the alkanethiol.

Using Nanoparticles in Microchips that Detect Chemical, Biological and Radiological Agents - What this Process Involves

Microchips for detecting chemical, biological and radiological agents that are based on nanoparticles are also being developed. Nanoparticles are laid on a chip, followed by a layer of a special polymer, and then a layer of receptor molecules, with each layer only a few nanometers thick.

In the presence of the warfare agent, a color change occurs. The extent of the color fade is indicative of the gas concentration. With trillions of specific sensor molecules on each chip, detection of only a few molecules of gas could be possible. The chips are designed to be embedded on military vehicles, clothes, buildings and other objects.

Sensors That Use Metal Nanocluster Resonance Technology - Applications and Processes

Sensors that rely on metal nanocluster resonance technology have potential application as detection systems for warfare agents. In these devices, metal clusters that are deposited on a substrate and positioned at a nanometric distance from a wave-reflecting layer act as nanoresonators and are able to receive, store, and transmit energy within the visible and infrared range. The sensitivity can be very high for biorecognition binding as well as structural changes in nucleic acids, proteins, and polymers.

Destruction of Warfare Agents Using Magnetic Nanoparticles and Nanocrystalline Metal Oxides

Destruction of stockpiled warfare agents and decontamination of exposed personnel is equally important to the military and for homeland defense. Both magnetic nanoparticles and nanocrystalline metal oxides have been investigated for this purpose.

Detoxification Processes Using Magnetic Nanoparticles

The use of magnetic nanoparticles to detoxify contaminated military personnel or civilians following a poison gas attack is under investigation by several research groups. Magnetic nanoparticles functionalized to bind with the foreign toxin are injected into the body and drawn through it using a magnetic field gradient. In order for the nanoparticles to be pulled along with the bound toxin molecules, they must have a very high magnetic moment. Gold coated iron, nickel and cobalt ferromagnetic nanoparticles have been employed in this “tag and drag” approach. Researchers are currently searching for cheaper and lighter weight organic coatings.

What is the mechanical engineering and what are the subjects can study the mechanical engineers

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Mechanical engineering and what are subjects mechanical engineers will study in Telugu so please watch it

Mechanical engineering is the discipline that applies the principles of engineering, physics, and materials science for the design, analysis, manufacturing, and maintenance of mechanical systems. It is the branch of engineering that involves the design, production, and operation of machinery.^[1][2] It is one of the oldest and broadest of the engineering disciplines.

The mechanical engineering field requires an understanding of core areas including mechanics, kinematics, thermodynamics, materials science, structural analysis, and electricity. Mechanical engineers use these core principles along with tools like computer-aided design, and product lifecycle management to design and analyze manufacturing plants, industrial equipment and machinery, heating and cooling systems, transport systems, aircraft, watercraft, robotics, medical devices, weapons, and others.

Mechanical engineering emerged as a field during the Industrial Revolution in Europe in the 18th century; however, its development can be traced back several thousand years around the world. Mechanical engineering science emerged in the 19th century as a result of developments in the field of physics. The field has continually evolved to incorporate advancements in technology, and mechanical engineers today are pursuing developments in such fields as composites, mechatronics, and nanotechnology. Mechanical engineering overlaps with aerospace engineering, metallurgical engineering, civil engineering, electrical engineering, manufacturing engineering, chemical engineering, industrial engineering, and other engineering disciplines to varying amounts. Mechanical engineers may also work in the field of biomedical engineering, specifically with biomechanics, transport phenomena, biomechatronics, bionanotechnology, and modeling of biological systems.

Advantages and disadvantages of nanotechnology

In this video we discuss about nanotechnology advantages and disadvantages in Telugu so please above to get clarified

What is friction and its types ,factors affecting the friction

in this video we explain about friction in telugu so watch this video to clear concept more

Friction is the resistance to motion of one object moving relative to another. It is not a fundamental force, like gravity or electromagnetism. Instead, scientists believe it is the result of the electromagnetic attraction between charged particles in two touching surfaces.

Scientists began piecing together the laws governing friction in the 1400s, but because the interactions are so complex, characterizing the force of friction in different situations typically requires experiments and can't be derived from equations or laws alone.

For every general rule about friction, there are just as many exceptions. For instance, while two rough surfaces (such as sandpaper) rubbing against each other sometimes have more friction, very smoothly polished materials (such as plates of glass) that have been carefully cleaned of all surface particles may actually stick to each other very strongly.

Mechanical Engineering Interview Questions and answers - Design, Safety and Maintenance PART 1

Q.1)  What safety precautions should be observed while working in the workshop ?

1) Keep shop floor clean, free from oil and other slippery materials.
2) Wear proper dress and avoid loose clothing and loose hair.
3) Wear shoes and avoid chapels.
4) Avoid playing, loose talk and funning inside the shop floor.
5) Keep good housekeeping and put all unnecessary items and rejected items in scrap box.
6) Learn everything about the machine before starting and clear all the doubts.
7) Keep a safe distance from rotating and sliding parts.
8) Never store inflammable materials inside or around the shop.
9) Never play with electricity, fire, parts with sharp edge etc.
10) Keep fire buckets and extinguishers ready for use.

Q.2)  What are the precautions to be taken to avoid fire ?

1) The buckets along with sand should be placed inside the workshop.
2) Switches and other electrical parts must be made of fireproof material.
3) Carbon dioxide gas should be place at required points in special containers.
4) Fire extinguishers of suitable type should be placed at accessible places.

Q 3)  What are the methods of extinguishing fire ?

1) Starvation. Separating or removing the burning material from the neighbour hood of the fire.
2) Blanketing. Preventing the air flow to the fire.
3) Cooling. Lowering the heat created by burning materials.

Q.4) What is a Drawing ?

It is a graphical representation of a real thing to define and specify the shape and size of a particular object by means of lines

5) What is Engineering Drawing ?

A drawing which is worked out an engineer for the engineering purpose is known as Engineering Drawing.

6) What is a sketching ?

This is freehand expression of the graphic language.

7) What do you mean by First Aid ?

First Aid is immediate and temporary care given to a person who affected accidental injury or a sudden illness before the arrival of doctor.

8) What is an accident ?
An accident is a unexpected and unforeseen event which may or may not injury to a person or a machine tool.

9) What are the standard sizes of drawing board as per Indian Standards?

As per Indian Standards :1250×900,900×650,650×500,500×350,350×250 sizes are available.

10) What are the functions of a scale ?

(a) To measure distance accurately.
(b) For making drawing to scale either in full size, reduced size or enlarged size.

11) What is the use of mechanical engineer’s scale ?

This is flat or triangular shape and used for making drawings of machines and structural parts in 1/8, 1/4, 1/2 or full size.

12) What is a Vernier Scale ?

This is used to measure very small unit with greater accuracy. It consists of a primary scale and a vernier scale.Vernier scale slides on the primary scale.

13) What is Representative Fraction ?

It is the ratio of drawing to the object. R.F=Length of the object in the drawing /Actual length of the object.

14) What is Drafting machine(Mini Drafter) ?

It is a device to do drawing work neatly and quickly.An attachment provided to move any position and may be adjusted at any required height.

15) What is a lettering ?

Lettering is the presentation of information data on a drawing.

16) Why Gothic style lettering is universally used in industry ?

Because it is more legible than other styles.

17) What are Section lines ?

Section lines are thin lines and used to show the cut surface of an object in sectional view.

18) What is a Centre line ?

Centreline is a thin line in the form long and short dashes. It indicates area of symmetrical parts, circles and path of motion.

19) Explain briefly the following lines used in Engineering drawing ?

(a)Dimension Lines (b)Extension Lines (c)Leaders
Dimension lines are the thin lines used to indicate extents and direction of dimension. These are terminated with arrowheads.
Extension lines are also thin lines and it used to indicate the termination of a dimension.
Leaders are used to direct notes or identification symbols to feature on the drawing.

20) What are Cutting Plane Lines ?

These are thick lines used to indicate the location of cutting planes in sectioning and the viewing position of removed pieces.

Mechanical Engineering interview questions and answers

1.What are the different types of fits? Explain?
2. What are the factors that can affect the Factor of safety selection?
3. What is heat treatment and why is it done?
4. What are the rules that must be kept in mind while designing castings?
5. What are the points that should be kept in mind during forging design?
6. Describe briefly the different cold drawing processes.
7. What are the different theories of failure under static load, explain briefly?

What are the different types of fits? Explain?

On the basis of Indian standards fits can mainly be categorized into three groups:
> Clearance Fit: These types of fits are characterized by the occurrence of a clearance between the two mating parts. The difference between the minimum size of the hole and the maximum size of the shaft is called the minimum clearance, the difference between the maximum size of the hole and the minimum size of the shaft is known as maximum clearance.
> Interference Fit: In these types of fits the size of the mating parts are predefined so that interference between them always occurs. The tolerance zone of the hole is completely below the tolerance zone of the shaft.
> Transition Fit: As the name suggests these type of fit has its mating parts sized limited to allow either clearance or interference. The tolerance zone of the hole and the shaft overlaps in case of such fits.

For a shaft designated as 40 H8/f7, calculate the tolerances.

Given: Shaft designation = 40 H8/f7
The shaft designation 40 H8/f 7 means that the basic size is 40 mm and the tolerance grade for
the hole is 8 ( i. e. I T 8) and for the shaft is 7 ( i. e. I T 7).
Since 40 mm lies in the diameter steps of 30 to 50 mm, therefore the geometric mean diameter,
D = Square root of (30 x 50) = 38.73 mm
We know that standard tolerance unit,
i = 0.45 x Cube root of (D) + 0.001 D
i = 0.45 × 3.38 + 0.03873 = 1.559 73 or 1.56 microns
i = 1.56 × 0.001 = 0.001 56 mm ...(1 micron = 0.001 mm)
The standard tolerance for the hole of grade 8 (IT8)
= 25 i = 25 × 0.001 56 = 0.039 mm
The standard tolerance for the shaft of grade 7 (IT7)
= 16 i = 16 × 0.001 56 = 0.025 mm

What are the factors that can affect the Factor of safety selection?

The factor of safety is used in designing a machine component. Prior to selecting the correct factor of safety certain points must be taken into consideration such as:
> The properties of the material used for the machine and the changes in its intrinsic properties over the time period of service.
> The accuracy and authenticity of test results to the actual machine parts.
> The applied load reliability.
> The limit of stresses (localized).
> The loss of property and life in case of failures.
> The limit of initial stresses at the time period of manufacture.
> The extent to which the assumptions can be simplified.

The factor of safety also depends on numerous other considerations such as the material, the method of manufacturing , the various types of stress, the part shapes etc.

What is heat treatment and why is it done?

Heat treatment can be defined as a combination of processes or operations in which the heating and cooling of a metal or alloy is done in order to obtain desirable characteristics without changing the compositions. Some of the motives or purpose of heat treatment are as follows:
> In order to improve the hardness of metals.
> For the softening of the metal.
> In order to improve the machinability of the metal.
> To change the grain size.
> To provide better resistance to heat, corrosion, wear etc.

Heat treatment is generally performed in the following ways:
> Normalizing
> Annealing
> Spheroidising
> Hardening
> Tempering
> Surface or case hardening

What are the rules that must be kept in mind while designing castings?

Some of the points that must be kept in mind during the process of cast designing are as follows:
> To avoid the concentration of stresses sharp corners and frequent use of fillets should be avoided.
> Section thicknesses should be uniform as much as possible. For variations it must be done gradually.
> Abrupt changes in the thickness should be avoided at all costs.
> Simplicity is the key, the casting should be designed as simple as possible.
> It is difficult to create true large spaces and henceforth large flat surfaces must be avoided.
> Webs and ribs used for stiffening in castings should as minimal as possible.
> Curved shapes can be used in order to improve the stress handling of the cast.

What are the points that should be kept in mind during forging design?

Some of the points that should be followed while forging design are:
> A radial flow of grains or fibers must be achieved in the forged components.
> The forged items such as drop and press forgings should have a parting line that should divide the forging into two equal halves.
> The ribs in a forging should not be high or thin.
> In order to avoid increased die wear the pockets and recesses in forgings should be minimum.
> In forgings the parting line of it should lie as far as possible in a single plane.
> For ease of forging and easy removal of forgings the surfaces of the metal should contain sufficient drafts.

Describe briefly the different cold drawing processes.

Some of the important cold drawing processes are as follows:
> Bar and Rod Drawing: In the case of bar drawing the hot drawn bars are at first pickled, washed and coated to prevent oxidation. Once this is done a draw bench is used for the process of cold drawing. In order to make an end possible to enter a drawing die the diameter of the rod is reduced by the swaging operation. This end is fastened by chains to the draw bench and the end is gripped by the jaws of the carriage. In this method a high surface finish and accuracy dimensionally is obtained. The products of this process can be used directly without any further machining.
> Wire Drawing: Similar to the above process the bars are first pickled, washed and coated to prevent any oxidation. After this the rods are passed through several dies of decreasing diameter to provide a desired reduction in the size ( diameter ). The dies used for the reduction process is generally made up of carbide materials.
>Tube Drawing: This type of drawing is very similar to the bar drawing process and in majority of cases it is accomplished by the use of a draw bench.

What are the different theories of failure under static load, explain briefly?

The main theories of failure of a member subjected to bi-axial stress are as follows:
> Maximum principal stress theory ( Rankine’s theory): This theory states that failure occurs at a point in member where the maximum principal or normal stress in a bi-axial system reaches the maximum strength in a simple tension test.
> Maximum shear stress theory ( Guest’s or Tresca’s theory): This theory states that failure occurs when the biaxial stress reaches a value equal to the shear stress at yield point in a simple tension test.
> Maximum principal strain theory ( Saint Venant theory): This theory states that failure occurs when bi-axial stress reaches the limiting value of strain.
> Maximum strain energy theory ( Haigh’s theory): This theory states that failure occurs when strain energy per unit volume of the stress system reaches the limiting strain energy point.
> Maximum distortion energy theory ( Hencky and Von Mises theory): This theory states that failure occurs when strain energy per unit volume reaches the limiting distortion energy.

introduction to automobile engineering in telugu

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1.introduction o automobile engineering

this video language is telugu and english & Tinglish

Automobile engineering is the one of the stream of mechanical engineering. It deals with the various types of automobiles, their mechanism of transmission systems and its applications. Automobiles are the different types of vehicles used for transportation of passengers, goods, etc. Basically all the types of vehicles works on the principle of internal combustion processes or some times the engines are called as internal combustion engines. Different types of fuels are burnt inside the cylinder at higher temperature to get the transmission motion in the vehicles. Most of the automobiles are internal combustion engines vehicles only. Therefore, every mechanical and automobile engineer should have the knowledge of automobile engineering its mechanism and its various applications.