Science and Technology - Part I

Science and Technology is an important part of Prelims syllabus. It covers not only the static portion but dynamic as well. In recent years, UPSC is emphasizing on dynamic cum analytical aspect of Science and Technology (S & T)

Example of additive process. Laying down of layers of material

How does the 3D printing works
3D printing is process of making a three dimensional object from a digital file. Digital file is basically a model of the design to be printed,it is created in the computer using CAD(computer aided Design) software or using a 3D scanner which scans the object and makes a 3D digital copy of it. This digital file is given as input to the 3D printer.

Not all 3D printers use the same technology. There are several ways to print and all those available are additive, differing mainly in the way layers are build to create the final object.

Some methods use melting or softening material to produce the layers.Another method is when we talk about curing a photo-reactive resin with a UV laser or another similar power source one layer at a time.

Additive Manufacturing processes is classified into 7 categories according to Standard Terminology for Additive Manufacturing Technologies. These seven processes are

1.Vat Photopolymerisation
2.Material Jetting
3.Binder Jetting
4.Material Extrusion
5.Powder Bed Fusion
6.Sheet Lamination
7.Directed Energy Deposition

Vat PhotopolymerisationA 3D printer based on the Vat photopolymerisation method has a container filled with liquid photopolymer resin which is layered to build objects and then hardened with UV light source.

Material Jetting In this process, material is applied in droplets through a small diameter nozzle, it is applied layer-by-layer to a build platform making a 3D object and then hardened by UV light.

Binder Jetting With binder jetting two materials are used: powder base material and a liquid binder. In the build chamber, powder is spread in equal layers and binder is applied through jet nozzles that “glue” the powder particles in the shape of a programmed 3D object.

Material Extrusion The most commonly used technology in this process is Fused deposition modeling (FDM).The FDM technology works using a plastic filament or metal wire which is unwound from a coil and supplying material to an extrusion nozzle which can turn the flow on and off.

The nozzle is heated to melt the material and can be moved in both horizontal and vertical directions by a numerically controlled mechanism,The object is produced by extruding melted material to form layers as the material hardens immediately after extrusion from the nozzle.

Powder Bed Fusion This technology uses a high power laser to fuse small particles of plastic, metal, ceramic or glass powders into a mass that has the desired three dimensional shape.

Sheet Lamination Sheet lamination involves material in sheets which is bound together with external force. Sheets can be metal, paper or a form of polymer. Metal sheets are welded together by ultrasonic welding in layers and then CNC milled into a proper shape.

Directed Energy Deposition This process is mostly used in the high-tech metal industry and in rapid manufacturing applications. The 3D printing apparatus is usually attached to a multi-axis robotic arm and consists of a nozzle that deposits metal powder or wire on a surface and an energy source (laser, electron beam or plasma arc) that melts it, forming a solid object.

3D printing

3D printing is a process of making three dimensional solid objects.The creation of a 3D printed object is achieved using additive processes. Hence 3D printing is also called as additive manufacturing. In an additive process an object is created by laying down successive layers of material until the entire object is created. Each of these layers can be seen as a thinly sliced horizontal cross-section of the eventual object.

Applications of 3D printing

• Medical industry- improved quality of care through 3D printed implants and prosthetics and also used in tissue engineering applications where organs and body parts are built.
• Aerospace & aviation industries-utilisation of 3D printing in the aerospace and aviation industries can, for a large part, be derived from the developments in the metal additive manufacturing sector.
• Automotive industry-the use of 3D printing in automotive is evolving from relatively simple concept models for fit and finish checks and design verification, to functional parts that are used in test vehicles, engines, and platforms.

National supercomputing mission:
This is a visionary program to enable India to leapfrog to the league of world class computing power nations.

The Mission would be implemented and steered jointly by the Department of Science and Technology (DST) and Department of Electronics and Information Technology (DeitY) at an estimated cost of Rs.4500 crore over a period of seven years.

The Mission envisages empowering our national academic and R&D institutions spread over the country by installing a vast supercomputing grid comprising of more than 70 high-performance computing facilities.

These supercomputers will also be networked on the National Supercomputing grid over the National Knowledge Network (NKN).

Two key departments of the Government of India, DeitY and DST will be implementing the mission jointly through two leading organizations. These are the Centre for Development of Advanced Computing (C-DAC) and the Indian Institute of Science (IISc), Bangalore.

Super computers
It is a computer which can perform process at high speed and has high memory, it is usually thousand times faster than ordinary personal computer

Speed of super computer is measured in FLOPS (floating operations per second)

Usually speed range of this generation’s super computers is tera(1012) or peta(1015)

India is trying to develop a super computer in the exa(1018) range.

As of now worlds fastest super computer is Tianhe-2 developed by china with a speed of 33.86 peta FLOPS

1st super computer developed in india was PARAM it was developed by centre for development of advanced computing(CDAC)
Currently india has 11 systems in the world top 500 supercomputers list

Some other prominent super computers are

• ANUPAM- used by Baba atomic research center
• SAGA-used by Vikramsarabhai space center
• Virgo- used by IIT madras
• Recently PARAM kanchanjunga was unveiled in NIT Sikkim
• PARAM series super computers are developed by CDAC

Rank	Used by	Name of the super computer
96	Indian Institute of Science,Bangalore	SahasraT
119	Indian Institute of Tropical Meteorology	Aaditya
145	Tata institute of fundamental research	TIFR - Cray XC30
166	Indian Institute of Technology Delhi	HP Apollo 6000
251	Centre for Development of Advanced Computing	PARAM Yuva - II
286	Indian Institute of technology Kanpur	Cluster Platform SL230s Gen8
300	CSIR Centre for Mathematical Modelling and Computer Simulation	Cluster Platform 3000 BL460c Gen8
313	National centre for medium range weather	Cluster Platform 3000 BL460c Gen8

By:Balalatha Mallavarapu