While Indians hold the simplistic notion of democracy as anybody’s right to use ear-damaging crackers and amplifiers anywhere any time, civilised people take a different view. One harsh criticism against the FAA (Federal Aviation Administration, the US body regulating civil aviation) is related to noise. It says the FAA’s routing policy at times causes the dumping of noise on “more densely populated, politically weaker, poor and/or minority communities”. What causes so much noise? It’s not the engine!
Experiments using a flight-simulating wind tunnel show that most noise happens to be of the “unsteady flow over various components – wing flaps and slats, horizontal and vertical tails, the landing gear and the edges and tips of various control surfaces”. It’s similar to what happens if a hand is stuck outside the window of a car that moves real fast. A little tilt, and the wind-made lift and drag fluctuate. An unsteady airflow builds up, causing audible noise.
Can we kill the noise? Well, there is a catch. Trained pilots know how to make the plane nose-point slightly downwards so as to put on enough speed to produce the lift it needs to go up still higher. But if they pitch in before the aircraft could pick up sufficient speed, the angle needed for the lift will cause a condition called stalling. And then the plane nose-dives towards the ground. Comparatively, smaller planes tend to stall more, and it happens mostly when they are at their slowest — that is, of course, while taking off and landing.
There is one simple reason why this is also the wrong time to stall, because the distance between the aircraft and the ground is crucially inadequate. Authentic records confirm that stalling accounts for 25 percent of all fatalities in small planes. Decades ago researchers were able to understand how to slow up the conditions that cause stalling. Strangely enough, sound in a sense seems to be the way out.
Earlier, other wind tunnels tests had indicated that air would flow smoothly over a plane’s wing at higher angles if you bathe its surface in sound by pointing a huge speaker at it. Since this is clearly impractical in the case of a huge object in flight, present research tries to integrate a sound source into the wing. One solution is a panel of silver-coated plastic film that expands and contracts when an alternating current is applied to it — like the skin of a drum, as one researcher put it.
SNEAK PREVIEW
1. CATS GET IT FROM HUMANS
There are a number of cats suffering from asthma whose condition has been triggered by things people do, or possibly by people themselves. In addition, cats with feline asthma syndrome are likely to suffer more if they are living in a household where people smoke, or where there are other potential allergens or irritants. A specific type of bacteria called Mycoplasma, which we find in human asthma patients, is present in a fifth of all lung fluid samples from asthmatic cats tested in the United States and Australia. And, for reasons unknown, Pedigree oriental breeds such as Siamese cats are more prone to the respiratory problem than other cats.
2. PUDDING CALLED TO TASK
Christmas pudding contains fruit, and is often coupled with fruits like berries, which are a good source of folate. And folate has been associated with changes to the length of telomeres, or tails of chromosomes, which has also been linked to cancer risk. This is one indication why the pudding affects your DNA, though the exact impact is unclear and likely to remain so. But any nutrition-related DNA modifications are long-term effects rather than one-off indulgences. If you eat the pudding day after day after day, it could damage your DNA, but as a one off probably not.
QUIZ No.214
1. Pop culture tabloid ‘People’ says one of the sexiest men alive is this scientist.
– Mike Shultz
– Martin Jackson
– Mandyam Srinivasan
– Michael Magna
1. Michael Magna.
2. Who sometimes make use of glide step?
– Army ants
– Marching bands
– Austrian ballerinas
– Monarch penguins
2. Marching bands
3. Say the name once, and it’s a son of David in the Bible. Say the name twice, and it’s a novel by …
– William Gibson
– William Faulkner
– William Burroughs
– William Golding
3. William Faulkner (the novel is ‘Absalom, Absalom!’)
4. This road-repairer looked into the eyes of a cat on a foggy night and invented an useful thing.
– Percy Shaw
– Percy MacKaye
– Percy Rockefeller
– Percy Thrower
4. Percy Shaw (who invented catseyes)
5. He sued the company that used his free, world-famous photo of Che Guevara in a vodka ad.
– Alberto Korda
– Andreas Gursky
– August Handlanger
– Alfred Stieglitz
5. Alberto Korda.