 |
|
| SCIENCE & TECHNOLOGY |
|
|
|
Lessons from Delhi Metro Electronic backseat driver New products & discoveries Prof Yash Pal
|
|
|
Lessons
from Delhi Metro For this purpose three types of tunnelling
machines were deployed and these were TBL (Tunnel Boring Machine) for
work in rock and hard soil, EPBM (Earth Pressure Balance Machine) for
work in the soft soils, and the NATM (New Austrian Tunnelling Machine)
which is versatile equipment and work both in the hard rock and soft
soils and this machine is not ‘boring type’ but excavates the
material, then places a protective layer of cement gunite (sprayed
cement) and temporary support if needed, till the permanent lining is
placed. Whereas in the other two, as the machines bore through the
material and slide forward, the permanent lining comprising of
pre-cast segments are placed in position. Whereas the EPBMs started
work on 19.8.2002 and the TBMs on 25.8.2003, the NATM was introduced
in the last phase of the work i.e. on 21.7.2003, to speed up the
progress of the tunnelling and to meet the scheduled target. So the
tunnelling work, started in August 2002, was completed in two years or
so. The balance 7 km of the underground corridor is being constructed
using ‘cut and cover’ method. The tunnelling was adopted only in
those areas where ‘surface disturbance’ was not permissible, such
as in the areas of Connaught Place, Chawri Bazar, New Delhi Station
and Delhi Main Station. TBMs were used in the hard rock areas where
quartzite type abrasive rock was encountered i.e. between the Delhi
Main Station and Chawri Bazar. Total length handled was around 1809
metres and task was completed in just 534 days, which gives the daily
progress of 3.38m (11 ft). EPBMs were used in soft soil reaches, such
as Kashmiri Gate to Delhi Main Station and also in the reach between
New Delhi Station and Connaught Place. With this type of machines some
5304m length tackled in 753 days, which put the daily progress of
about 8m/day (26.25 ft.) which is creditable. NATM was deployed in
the reach between Chawri Bazar and New Delhi Station. The length
tackled was 767 m and time involved 567 days, which puts the daily
progress at just 1.35 metres/day (4.45 ft).
Problems faced
Twin
tunnels, for UP and DOWN movements of trains involved pacing of very
high grade (M45) concrete to yield a completed tunnel of inner
diameter of 5.7 m. The underground metro corridor is being opened in
two stages, with the Delhi University to Kashmiri Gate in December
this year and rest in second stage around June 2005 which would extend
the line to Central Secretariat. So by June 2005, two underground
metro lines would cross over each other under the surface in the
Connaught Place. Barakhamba road-Dawarka line would run along
the direction indicated by the Metro Boards currently dotting the
Barakhamba Road. There would be four Subways to access the Connaught
Place Metro Station, from where trains will go in four different
directions such as Super Bazar, Jan Path, Baba Kharak Singh Marg,
between Minto Road and Panchkuian Road. There will be a Central Park
and an amphitheatre, a green park near the Connaught Place Metro
Station (CPMS). CPMS will have two levels where separate lines will
run. Through Subway one will enter the 1st levels which will be the
Concourse Level. Here one will be able to buy the ticket and then
enter the 1st level Platform, from there one could proceed to Central
Secretariat and Vishwavidyala (University) line. For other locations
one would have to descend to the IInd Level. In this structure, ‘fire
safety measures’ adopted will conform to international standards.
There would be provision of evacuation of all people in just six
minutes. Move is on to extend the system to other surrounding areas.
Move is underway to cover area upto Gurgaon through a line starting
from IFFCO Chowk Gurgaon to Mahrauli and also to Noida City, Sector 18
and to New Ashok Nagar, New Delhi. Looking at the encouraging results
obtained by the Delhi Metro Rail Venture, there is a strong case for
the adoption of the similar set by other metros and state capitals
while planning their MST (Mass Rapid Surface Transport) Systems. |
|
Electronic backseat driver Drivers may soon have no excuse for ignoring road signs. Australian scientists have invented an electronic driver’s assistant system, similar to the backseat driver who forever points out road signs and warns against speeding. “The Australian invention is part of a global effort to make drivers more aware of road signs, especially those concerned with safety,’’ says New Scientist magazine. The new driver’s assistance system (DAS) developed by National Information and Communications Technology Australia (NICTA) in Canberra detects road signs and warns drivers to slow down. “DAS uses three cameras: one to scan the road ahead and a pair to monitor where the driver is looking,’’ the magazine said. A computer system fitted behind the dashboard collates the information with data on the speed the car is going. If it appears the driver has not seen a sign or has not slowed down, a warning is issued. In preliminary tests, DAS performed “pretty well’’ even at high speeds, according to its developers. They plan to test it in full-scale road trials with many types of road signs soon. — Reuters
|
|
New products & discoveries New research results from Saint Louis
University and other institutions across the country found the
"heart jacket" technique helped patients feel better and
reduced the likelihood that they would need a heart
transplant. "There was a clear improvement in the size and shape
of the heart, returning it to a more normal configuration," says
Paul Hauptman, M.D., a SLUCare cardiologist and associate professor at
Saint Louis University School of Medicine. "It’s a potentially
revolutionary approach." The CorCap Cardiac Support Device is an
investigational, mesh-like heart "jacket" that is slipped
around the heart during chest surgery and stitched in place to prevent
any further enlargement. It is made from a custom knitted polyester
fabric and is intended to be an adjunctive therapy for patients with
moderate to severe heart failure.
E-devices minus lead
The innovation is a
type of piezoceramic-a material that shrinks or swells when an
electric field is applied. The ringers in cell phones, for instance,
are made from piezoceramics that vibrate at high frequencies in
response to an electric signal. The effect also works in
reverse-squeeze a piezoceramic, and it generates an electric field.
That produces a spark in a barbecue igniter, for instance. Sonar
systems, fuel injectors, and many sensors also rely on these
shape-changing materials.
Dino armour was perfect Their armour was perfect; even their eyelids
consisted of plates of bone. What are known as ankylosauruses are
among the best armoured animals known to us. These herbivores were up
to 10 metres long, with a tail ending in a huge bony club - ‘probably
used as a weapon’, says Torsten Scheyer, ‘even though they
definitely could not simply swing it back and forth; the whole
construction was simply too stiff for that.’ Torsten Scheyer has
examined the dinosaurs’ armour as part of his diploma thesis. The
results are astonishing: ‘The armour plating is not nearly as
similar to those of the crocodile as was previously assumed,’ he
adds. ‘Their microstructure is substantially more complex, at least
in some types of ankylosaurus’. |
|||
| HOME PAGE |
UNDERSTANDING
THE UNIVERSE Prof Yash
Pal
What is a white hole? What is the difference between a white hole
and a black hole? Equations that describe the formation of a
black hole would be equally valid if the direction of time were
reversed. In that case you would be describing something like a black
hole bursting out with light matter and energy. This might be termed
as a white hole! The only problem is to find a way of reversing time!
As far as I know, while there is definite evidence for the existence
of black holes there is none for "white holes". Scientists
like to speculate and dream — even the impossible. You could, of
course, say that the origin or origins of the universe was/were just
one or more white holes bursting forth — just one such explosion if
you believe in the big bang theory and more if you want some sort of
continuous creation! We know that matter can be converted into
energy during certain processes like nuclear fusion. Can energy be
converted back into matter? If yes then is it just theoretical or is
there an experimental evidence for this? Equivalence of mass and
energy has been shown in a large number of experiments and natural
phenomena. It was first seen in cosmic ray studies when positive
electrons were discovered. Production of a host of new elementary
particles happens in interaction of cosmic rays but in a much more
controlled manner in accelerator experiments. For this conversion to
occur all that needs to be assured is that the discrete and dynamical
conservation laws are not violated. A high-energy photon cannot be
converted into an electron positron pair traveling freely in vacuum.
This can happen only if this happens next to another particle or
nucleus that can help to conserve overall energy momentum. Take it
from me. This two-way conversion is an established fact. I might draw
your attention to the fact that in evolutionary cosmology the universe
itself began as pure energy and all the mass you see was the result of
subsequent development. E = Mc^2 of Albert Einstein stands fully
vindicated. Where would be the poles of a spherical magnet? The
magnets you are familiar with are produced by aligning the microscopic
magnetic domains of a magnetic material. We assign magnetic moments
even to individual charged particles whenever they have a spin angular
momentum. Nuclei of atoms also have spins. Think of them as tiny
magnets that, in a non-magnetised state of the bulk material, are
randomly oriented. Magnetisation is a process of alignment. Therefore
for a magnet in a spherical shape the poles would be positioned
depending on the way the sphere was magnetised. It might happen,
though, that in an irregular shaped material, internal interaction
between domains might produce a localised unpredictability in the
magnetic field. How do computers keep track of date and time even
when they are switched off? Computers have electronic watches
very much like the modern watches we wear on our wrist. They have
small batteries that continue to run the clock when the power is off.
Ordinary button batteries we use in our watches would do, but small
rechargeable batteries are also possible. Even for computers, function
needs energy. |
All the tunnelling of Phase I of the
Delhi Metro Rail
Project was completed on September 3, 2004. In this phase 11 km long
underground corridor of the Metro, running from Delhi University to
Central Secretariat, involving tunnelling over a length of 7880 metres
has been completed.
The concept is simple: to halt
deterioration of the heart muscle, wrap it in a mesh-like net to
prevent further enlargement in patients with heart failure. It’s
like a jacket for the heart.
Scientists
in Japan have created a new material that could someday replace toxic
components in many electronic devices. With growing concern over the
disposal of cell phones, computers, and other gadgets containing
hazardous materials, the team proposes that its discovery will render
future devices less harmful to the environment. 