Wednesday, July 30, 2014

Iron Dome: The Most effective missile shield in the world

An Israeli missile is launched from the Iron Dome
On July 29 Gaza felt the heaviest air and artillery assault from Israel, destroying key symbols of Hamas control, shutting down the territory’s only power plant and leaving at least 128 Palestinians dead on the 22nd day of the war. It is by far the deadliest day of the on going fighting.

As of the time of writing, 1, 229 Palestinians already perished, 7, 000 have been wounded and hundred thousands were displaced, majority of them are civilians. In comparison, Israel says it has lost 53 soldiers, 2 Israeli civilians and a Thai national.

The number of casualties will surely increase in the coming days as the Israel’s Prime Minister Benjamin Netanyahu warned Israelis to be prepared for a “prolonged war”.

But despite the heavy Palestinian losses, Deif, the commander of the Hamas military wing, said the fighting would continue. "There is not going to be a cease-fire as long as the demands of our people are not fulfilled," he said.

Though Israel has the better military, technology, equipment, and engineering capabilities, Hamas is still capable of wreaking havoc on its enemy. They have stockpiled of short and middle range rockets smuggled from their supporters, mainly Lebanon and Iran. But one of the main reason Hamas only inflicted a small number of Israeli fatalities is the Israel’s prominent Iron Dome.

Iron Dome is a mobile all-weather air defense system developed by Rafael Advanced Defense Systems. The system is designed to intercept and destroy short-range rockets and artillery shells fired from distances of 4 kilometres (2.5 mi) to 70 kilometres (43 mi) away and whose trajectory would take them to a populated area. Israel hopes to increase the range of Iron Dome's interceptions, from the current maximum of 70 kilometres (43 mi) to 250 kilometres (160 mi) and make it more versatile so that it could intercept rockets coming from two directions simultaneously.

How the Iron Dome works

Iron Dome was declared operational and initially deployed on 27 March 2011 near Beersheba. On 7 April 2011, the system successfully intercepted a Grad rocket launched from Gaza for the first time. On 10 March 2012, The Jerusalem Post reported that the system shot down 90% of rockets launched from Gaza that would have landed in populated areas. By November 2012, official statements indicated that it had intercepted 400+ rockets. On 19 November, defense reporter Mark Thompson wrote that while these numbers were impossible to confirm, the "lack of Israeli casualties suggests Iron Dome is the most-effective, most-tested missile shield the world has ever seen."

Though with some weaknesses as explained on this article, Yair Ramati, the director of the Homa Administration within Israel’s defense ministry, said that Iron Dome has improved significantly since its first use in 2011, staying “one step ahead of the enemy.” But he said that Hamas is constantly probing the system for weaknesses.

The nightmare scenario for Israel would be Hamas or other foe equipped with cruise missiles that can twist and turn in flight to evade interceptors. Or, perhaps sooner, a simultaneous launch of so many rockets that Iron Dome can’t shoot them all down.

But let’s just hope that both parties will reach a cease fire sooner rather than later.


Wednesday, March 19, 2014

The development of the CNC machine

What are CNC machines?
Computer Numerical Control (CNC) machines are automated milling devices that are designed to make industrial components without the need for direct human assistance. Using coded instructions that are sent to an internal computer, these machines enable factories to manufacture parts accurately and quickly.

The history of CNC machining
Computerised Numerical Control or CNC as it is now known, first came about after World War II as a result of the US Air Force’s desire to produce more accurate and complex parts.  The modern machine’s advent can be traced back to the invention of the numerical controlled machine made by John T. Parsons.

First concept developed for the manufacture of helicopter blades
Alongside Frank L. Stulen, John T. Parsons first utilised computer methods to overcome machining setbacks, especially the accurate interpolation of the curves found in helicopter blades. In the process of developing smoother rotors, Parsons and Stuler generated an early version of a Numerical Control (NC) machine.

Developed with assistance of MIT
To further develop this machine, in 1949, Parsons turned to Gordon S. Brown’s Servomechanism Laboratory at the Massachusetts Institute of Technology (MIT). At MIT, a feedback system designed to gauge how far the controls had turned was developed.  
While the US Air Force halted its funding in 1953 due to expense, the project was resumed by Giddings and Lewis Machine Tool Co. who reduced expense but improved quality and efficiency.

Reduced production time from 8 hours down to 15 minutes
The first CNC machine was developed when John Runyon managed to produce punch tapes under computer control. By doing this, he managed to reduce the normal production time of 8 hours down to 15 minutes. By 1956, the US Air Force had accepted the proposal to produce a generalised programming language for NC.
The invention of CNC machines paved the way for automated tools that enabled efficient production for manufacturers. Today’s CNC machines bear little difference with the original machines in terms of concept. Both produce outputs in three dimensional directions: X and Y axes and depth.

The types of CNC machine
The types of CNC machine that exist today include the following:
CNC turning lathes –  CNC turning lathes produce parts by turning rod materials and feeding a cutting tool into the turning material.
CNC milling machines – Using a rotating cylindrical cutting tool, CNC Milling utilises a machining process similar to both drilling and cutting. The cutter in a milling machine has the ability to move along multiple axes and can create a variety of shapes, slots and holes   

CNC routers - CNC routers are similar to handheld routers but the tool paths are instead controlled via computer numerical control. CNC routers can be used for cutting various hard materials including wood, composites, aluminium, steel, plastics and foams.

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