|SCIENCE TRIBUNE||Thursday, February 28, 2002, Chandigarh, India|
Nuclear weapons: types and effects
NEW PRODUCTS & DISCOVERIES
Driver-free transport is here
A shiny white pod that began road test this month may well be the taxi of the future.
The pod, known as ULTra — Urban Light Transport — could make driver-free transport a reality and not just the stuff of futuristic fantasy.
"It will be he first in the world," said Richard Treychenne, director of business development at ULTra’s makers, Advanced Transport Systems Limited.
The pod — which seats up to four passengers — is the brainchild of Bristol University’s Martin Lowson, who is no stranger to making science fiction dreams come true.
His past projects include the Apollo Moon-landing programme in the United States.
The first stage of the ULTra project will have 30 pods circling the Cardiff Bay area in Wales by 2004 if all goes according to plan, Treychenne said.
Next, the pods would move to the centre of the Welsh capital.
At a maximum of 25 miles (30 km) per hour, ULTra may not reach cosmic speeds but should still speed past cars and buses stuck in traffic.
The battery-powered pods will operate on a single 1.5 metre (five foot) track — less than half the width of a single lane of road — and recharge at every stop to keep their energy levels topped up.
Resistant to vandalism, snow, rain and ice, the vehicles will be designed to stop automatically if they sense an object in their path.
ULTra pods could work as an automated personal taxi system. Passengers will ‘hail’ the pod from a designated stop, where they select the required destination along a set route.
When the pod pulls up, the passengers swipe a smart card giving the travel details and ULTra carries them directly to their chosen stop.
Rubber wheels ensure a quiet journey and security cameras at every stop increase passenger safety.
Its designers say ULTra could spell the end of long taxi queues, because a passengers would find on-call pods at designated stops at least 90 per cent of the time.
This efficiency would come from a large number of pods in circulation, and by shortened journey times without conventional traffic jams.
Advanced Transport System estimate that building an ULTra network would cost about one-third to one-half of the amount needed for a light railway.
Connecting Cardiffs city centre to its waterside region is expected to cost 45 million pounds ($65 million). Old car parks and shops will be converted into express stations for hospitals and other focal points in the city.
The pods will be accessible to the disabled, as well as passengers with bicycles or prams, with lifts taking people up to high-rise stations.
Designer hope that the experience will cost about as much as an ordinary bus journey, or even less if passengers are prepared to share their pods.
Wherever possible, ULTra will run along the ground, but some routes might require tracks to be raised on pillars above roads, creating a truly futuristic look.
"In a modern development like the Cardiff waterfront area we feel that the system will match the architecture very well," said the ULTra design team.
Available on demand and based on intelligent, battery or fuel-cell driven taxis, the ULTra system takes you to your destination using a purpose-built guideway network. Buying a ticket programmes the waiting cab to take you where you want to go and the technology selects the quickest and best available route. On arrival, the passenger simply leaves the cab which will either wait for the next fare, or take itself to another location with known demand.
"The principles of public transport have remained unchanged for over 200 years," comments Martin. "The public is expected to travel together, along predetermined routes and at prescheduled times. ULTra breaks this transport model to provide public transport which takes individuals or small groups where they want to go, when they want to."
The potential market for ULTra is massive. The system could replace 25- 30 per cent of trips made by car and the majority of trips made by bus. It is particularly suited to medium-sized cities — which house the majority of the world’s population.
ULTras’s flexibility offers
enormous benefits over traditional public transport and also delivers
improvements in sustainability. For both emissions and energy use, the
system performs three times better than current public or private
transport, rising to 10 times better at peak travel times. One ULTra
vehicle will do the job of approximated 60 cars. Yet the system is
predicted to be commercially viable at fares levels similar to buses.
Installation costs are projected at about one-third the cost of
equivalent light rail systems. Reuters
Nuclear weapons: types and effects
NUCLEAR weapons are potential threats to the basic existence of society. A nuclear detonation results in an environment consisting of a blast, thermal pulse, neutrons, x and gamma ray radiation’s, electromagnetic pulses and ionisation of the upper layer of atmosphere. The effects of the blast can be in the form of ground shock, water shock, and radioactive fallout. The energy liberated per unit mass in a nuclear detonation is of the order of several tens of million degrees centigrade. These high temperatures result in the vapourisation of the nonfissioned parts of the nuclear weapon and thereby the release of electromagnetic radiations in the form of fireballs. The cooling of fireball results in the condensation of vapourised particles to form a cloud of solid particles.
Nuclear weapons are classified as tactical and strategic. Tactical nuclear weapons have an explosive power of the order of 1 MT. These can wipe off the enemy in a single blow. Strategic nuclear weapons operate in the range 1 MT to above 550 MT. These cause mass destruction of a city as a whole and also certain fortified areas. Neutron bomb also comes under the category of strategic weapons. These bombs kill the biological organisms and the buildings, vehicles and other infrastructure remain intact.
The power of a nuclear explosion manifests itself in the surroundings in the form of blast, thermal radiation and nuclear radiation. These depend on the location and environment of the burst. The detonations at low heights (surface bursts) with a moderate weapon result in distributing the energy as 40% blast, 40% thermal radiation and 20% as nuclear radiation. The detonation above 35 km of earth’s surface is called the AirBurst. These blasts result in devastating damages and injuries. The explosions carried out below the surface or under the water are called subsurface bursts.
The devastating pictures of Hiroshima due to
nuclear explosions send shivers down one’s spine. The society as a whole
should join hands to convert this menace into a blessing, otherwise the basic
existence of the society is in danger.
"SMART FLUID", a liquid polymer, which gets solidified in the presence of a magnetic field and changes back into liquid within seconds after the magnet is removed, has been developed by a scientist of the National Physical Oceanography Laboratory (NPOL) in Kochi.
The "smart Fluid" has many applications, including for making automobile brakes, clutches, moulds, vibration damping, tunable elastomers and safety valves, Dr Reji John, who developed the fluid, and has exhibited it at the ongoing ‘Swadeshi Vijnana’ mela told PTI
Dr John said the presence of the magnetic field builds up the viscosity in the fluid. The initial viscosity of the fluid is around 500 CPS (Cetri Poise). If magnetic field of one gauss is applied, viscosity becomes 1.5 lakh CPS within 0.2 sec and as soon as the magnetic field is removed, it touches its initial viscosity of 500 CPS immediately, he said.
Dr John said the fluid, called ‘Magnetorheological’
was developed by him six months ago and can have wide defence
applications. The institute has applied for patenting in US, UK,
France, Japan, besides India, he said. PTI
NEW PRODUCTS & DISCOVERIES
ELECTRIC bikes have never been cool. After all, what self-respecting rider would let a battery do all the work? But fuel-cell technology, which uses pollution-free hydrogen gas to generate an electric current, could ignite electric-bike sales.
The first prototype, from Italian bikemaker Aprilia, stores compressed hydrogen in a 2-liter metal canister housed in the frame. With a top speed of 20 m.p.h., the bike won’t win the Tour de France. But it weighs 20% less than regular electrics and travels twice as far, about 43 miles, before it needs more gas. Now that’s cool. Availability: In 2003, for approximately $ 2,300. To learn more: www.apriliaenjoy.com
Novel plastics films
To minimise the risk of active agents that kill microorganisms from being washed out and posing a risk to human health, researchers have successfully treated plastics with chemicals which bind the agents more firmly.
Microorganisms can be extremely helpful — cleaning up effluent and contaminated soil, giving the desired flavour to foodstuffs such as cheese, yogurt and wine, producing essential vitamins in human bodies and manufacturing drugs such as insulin and antibiotics in industrial fermenters.
But most people become aware of their presence when they multiply out of proportion causing outbreaks of disease, spoiling food or causing wood to rot.
However, the active agents utilised to kill microorganisms often pose a risk to human health. The biocides also have another disadvantage that over time, they are washed out and lose their effectiveness, a report in Fraunhofer Gesellschaft said.
With the solution demanding a more firm binding of these biocides to the material being treated, scientists at the Fraunhofer Alliance for Polymer Surface, POLO, have developed a new technique of using relatively innocuous polyammonium compounds and natural agents and coupling them chemically to the surface of plastic materials. PTI
Iced organs for transplant
Scientists in Canada deep-froze the ovaries of lab rats and then successfully transplanted them, an achievement that offers hope to women and girls facing sterilising chemotherapy, reports AFP.
Cryopreservation — freezing in liquid nitrogen — has often been explored for preserving organs but the results have been disappointing, mainly because the freezing and thawing process inflicts damage to the tissue.
A team led by Roger Gosden of the Department of Obstetrics and Gynaecology at McGill University, Montreal, removed the right ovary, which was attached to the fallopian tube and upper part of the uterus, from 15 female rats.
Eight sets of organs were transplanted within an hour to other rats which had the corresponding organ removed.
The other seven sets were soaked in a preservative mixture of dimethylsulphoxide and fructose for 30 minutes, and then slowly chilled to -7 degrees Celsius in a standard liquid nitrogen freezer. The organs were thawed out the following day and then implanted.
All of the recipient rats were genetically identical to the donor rats, something that greatly reduces the risk of organ rejection.
Even so, the Gosden team says, the outcome should encourage a revival of interest in cryopreservation, especially if such obstacles as the toxicity of chemical additives and the formation of ice crystals in the blood vessels during the freezing process can be overcome. PTI
Race for molecular computer
Scientists at Hewlett-Packard Co and UCLA said they have patented a means of getting around a significant hurdle in the race to build computer chips out of individual molecules.
The breakthrough could give researchers an efficient way to control the flow of information on such minuscule circuits — a requirement if tiny but enormously powerful molecular computers are ever to become a reality.
Researchers in the burgeoning field of nanotechnology hope to someday create computers small enough to be sprinkled like dust, embedded in materials or perhaps even injected into the bloodstream to serve as diagnostic sensors.
The Hewlett-Packard-UCLA team, which is partly funded by the US Defence Department, already has patented a way to connect molecularscale switches with chemical "wires" that are just six to 10 atoms wide and two atoms tall about one hundredth the size of the tiniest wires on chips.
Last year, R Stanley Williams of HP and Philip Kuekes and James Health of UCLA developed a chemical process and computer program that would allow the circuitry to be mapped like perpendicular city streets. In that way, a computer’s central processing unit could know exactly where on the molecular grid certain information was being stored.
But simply providing routes for electrical impulses to travel is not enough. For a molecular circuit to really work, researchers need to have a way of managing the way the signals travel.
So to govern their small city, the HP-UCLA team proposed creating a rough equivalent of traffic lights. It was that electric-chemical process that won a patent in November.
"I believe that in 10 years we definitely will have hybrid molecular-silicon circuitry," Williams said. PTI
Wind turbines for stable power
Researchers have concluded that wind turbines can help cope with fluctuations in the mains voltage thereby keeping the voltage in the electricity network at a constant level.
At the moment, the task of maintaining the stability of the mains voltage is left entirely to power stations. In future, sustainable energy will become more important. Wind turbines and other sustainable energy sources will then need to help stabilise the mains voltage.
Modern wind turbines are a good means of coping with fluctuation in the mains voltage which occur when the demand for energy increases suddenly (for example, when a factory turns on heavy machinery) or the supply decreases (for example, if a nearby power station suddenly goes off line).
Science & Technology crossword
1. Important for foundation design.
5. Embed a joist in concrete.
8. Overhead reservoir (abbr.)
10. For access to the top.
12. Long handled tool to scrap weeds.
13. An important plumbing special.
15. Provided when steel bars are shorter in length.
18. A course provided on outer projections over windows.
19. A streamlined flow is a ‘ ……….one’.
20. Decide it with respect to road level (abbr.)
21. Most important point on a building drawing.
22. Apply epoxy on this surface to protect from weathering.
1. Excites oscillations in tall chimneys.
2. A very useful survey instrument.
3. Prefer a residential plot facing this direction.
4. Abbr. To denote elevation.
6. Develops in concrete under constantly sustained load
7. Lower edge of the inclined roof surface.
9. ‘…….window’ is a curved bay window.
11. Reduced Level (abbr.)
12. Used to supply water temporarily.
14. An engineering graduate (abbr.)
16. Top most point of a building.
17. Foot level of a window.
20. Floor area of a house (abbr.)
Solution to last week’s crossword: