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Towards thermal houses Good news for smokers Handsfree too
are dangerous
New Products and Discoveries Prof Yash
Pal PROF YASH PAL |
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Towards thermal houses THE unique weather conditions in our country — very high ambient temperatures — make feasible the construction of residences which can employ solar energy for cooling as an integral part of their design, as it is the cooling, that matters most in summer in our country. One of the requirements where solar energy can be put to use for cooling or heating a building is that of minimising the loads. The costs of solar heating and cooling equipment is currently high when imported from abroad. In fact it is still to be developed in our country as no such equipment is available in the market for residential applications. The approach described here is to look at proven building materials and methods and put them together in a combination which produces a house of significantly improved thermal characteristics ("thermal house", for short) at a cost comparable to local standard construction. Our present-day residences usually employ electric airconditioners for cooling and electric room heaters/convectors for heating. The houses have no insulation at all anywhere in the house. With sufficient insulation tremendous cooling and heating loads will be decreased. This is what is required in a thermal house. The house is assumed to have 1700 sq. ft. of airconditioned living space, 1460 sq ft of exterior wall and 140 sq ft of single glass windows. Attic ventilation can be adjustable for liberal exchange with outside air during the cooling season and for low ventilation during the heating season. Three-foot roof everhung for summer shading of windows and walls is also there. With no insulation in the roof, walls and ceiling, cooling load will be very high and an electric airconditioner of even 5 ton (20 KW) capacity may not be sufficient to cool the house, leaving for the moment the cost of electricity consumed in running the airconditioner. Cost of running an airconditioner of 1.5 tons is about Rs 10 an hour. In a thermal house our aim is to utilise solar energy for cooling/heating and design a competitively priced residence to ensure an economical, low heat load structure, and the choice of solar collection devices together with cooling systems to be employed based on lithium bromide vapour absorption cycle. The house would be served/serviced by an air handling unit containing a hot and a chilled water coil. The thermal house is highly insulated, choice of solar collectors and the size of chiller should now fulfil the requirements. The chilled water needed by the air handling unit will be supplied by a lithium bromide absorption chiller. This type of unit uses water in the 87 to 120°C (188 to 250°F) temperature range, and can operate in the narrow range of 87 to 104°C (188 to 220°F). Nature of the collectors would be site specific as simple flat plate collectors can be put to use if providing water temperature is in this range, otherwise non tracking evacuated tubes, with reflective reinforcement type collector with seasonal adjustment would be ideal. Even concentrating collector would serve. The size of the lithium bromide absorption chiller should be about 3 ton (12 KW) capacity. The table given below gives a fairly good idea of the cost
Initial cost comparison of conventional to solar Heating and Air Conditioning
The thermal house has the lowest cost.
If Rs. 3500/ month is the average bill to heat and cool the standard construction, then Rs 5.7 lakh spent extra on thermal house would be recovered in 13.6 years, not a bad proposition when considered over, say the 20 to 30 years needed to pay off the mortgage of the house. This very idea can be extended for big houses, schools, libraries, hotels, hospitals etc. and even malls. During summers the buildings would be cooled and during winters hot water and hot air for heating would be there. The writer is former Prof. of Mech. Engg.
P.E.C. Chandigarh.
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Good news for smokers THE mental boost smokers get from nicotine is linked to the same area of the brain in mice as its addictiveness and the two are probably inseparable, French scientists have said. In a study that may hold insights into ways to help people quit smoking, researchers at the CNRS-Pasteur Institute in Paris showed that receptors on cells in the ventral tegmental area (VTA) of the brain are involved in nicotine’s addictive and cognitive qualities in mice. ‘’This is a very critical area for self-administration for nicotine in the brain,’’ said Jean-Pierre Changeux, who headed the research team. The VTA is involved in responses to natural rewards such as food, sex and the effect of drugs. Addictive drugs activate the release of dopamine, a chemical linked to pleasurable sensations, which is made in cells of the VTA. Scientists have known that a family of receptors, or doorways into cells, called nicotinic acetylcholine receptors are involved in addiction to smoking. Changeux and his team genetically engineered mice so they lacked a gene for a portion of a nicotine receptor, to discover the impact it would have on how the mice functioned. The mutant mice had a mild learning impairment and unlike normal mice, which had learned to press a lever to self-administer nicotine, they showed no interest in getting nicotine. ‘’When there is a loss of the nicotine receptor then there is a loss of cognitive function in the mouse,’’ Changeux, who reported the finding in the science journal Nature, told Reuters. But when the scientists re-injected the gene, the mice’s cognitive function was restored. The rodents were also more likely to seek out nicotine. ‘’Given the intricacies of the brain, it is striking that reintroduction of a single molecule to just one small area of the brain should so dramatically affect behaviour,’’ said Julie Kauer of Brown University in Providence, Rhode Island, in a commentary in the journal. Changeux and his team do not know whether humans would react in the same way but they believe their work could advance the search for drugs to cure addiction. If researchers could find a way to stop nicotine attaching to brain cells, it may be possible to prevent addiction. Drug companies are already trying to harness the positive effect of nicotine to treat brain disorders such as memory impairment in Alzheimer’s disease. |
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Handsfree too
are dangerous PEOPLE talking on cell phones while driving are at least four times more likely to be involved in a collision and using a hands-free device does virtually nothing to reduce the risk, new research has shown. The University of Sydney study, based on a survey of 400 car crash victims, found that people using hand-held phones were five times more likely to have a collision. It also found that people using hands-free devices while driving were four times more likely to have a crash resulting in injuries. Governments around the world, including Germany, Australia and several US states, have prohibited the use of hand-held cell phones while driving, but the new research, published in the British Medical Journal, suggests the ban should be widened. “This research has highlighted that hands-free isn’t fine, that it does also elevate your risk of crashing,” study co-author
Professor Mark Stevenson says. “The key message here is that we need to basically avoid using phones whilst driving. That is what is going to minimise your risk,” said Stevenson, of The George Institute’s Injury Prevention and Trauma Care Division at Sydney University. The research included talking on phones and sending text messages while driving, he said. The study involved more than 400 drivers and was conducted in the emergency departments of three hospitals in Western Australia state. Dr Suzanne McEvoy, the report’s principal author, said more than half of the study participants reported having a hands-free phone device in their vehicles. “The increased likelihood of crashing was not influenced by gender, age of the driver or availability of a hands-free device,” McEvoy said. Stevenson said respondents agreed to have their billing records made available by their phone service providers. Using those records, researchers compared phone use just before the collision with journeys taken by the same drivers in the week before
their crash. “This is the first study that’s looked at outcomes that are injury-related,” Stevenson said. He said researchers looked at whether drivers had been using their phones up to 10 minutes before their collision. “The majority were in a very short time period just before the crash.”
— Reuters |
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New Products and Discoveries
No previously studied mammal stays awake for so long, says Jerry Siegel of the University of California, Los Angeles (UCLA), an investigator in the study. In the months following their wakeful period, baby whales and dolphins-and their mothers-ramped up slowly to sleep amounts typical of normal adults, Siegel and his colleagues report. The infants’ sleep pattern contrasts with that of other mammals, which need extra sleep during infancy and gradually sleep less as they age. Frogs are near
extinction Before the arrival of Spanish colonisers some 500 years ago, Indians in what is now Ecuador dipped their arrowheads in venom extracted from the phantasmal poison frog to doom their victims to convulsive death, scientists believe. More recently, epibatidine — the chemical which paralysed and killed the Indians’ enemies — has been isolated to produce a pain killer 200 times more powerful than morphine, but without that drug’s addictive and toxic side effects. Pharmaceutical companies have not yet brought epibatidine to market but hope to discover other chemicals with powerful properties in frogs, which are a traditional source of medicine and food for many of Ecuador’s Indians. They may went to hurry because the treasure trove of the world’s frogs and toads is disappearing at a catastrophic rate. And it’s not just potential medicines which could be vanishing but creatures of beauty. “Frogs and toads are becoming extinct all over the world. It’s the same magnitude event as the extinction of the dinosaurs,” said Luis Coloma, a herpetologist, or scientist dedicated to studying reptiles and amphibians, in Ecuador — the country with the third greatest diversity of amphibians.
— Reuters Intelligence and happiness Being intelligent is no guarantee of a happy old age, researchers say. They studied 550 people born in Scotland in 1921 whose mental ability had been tested at age 11 and again at 80 to determine if intelligence over a lifetime was linked to happiness. “In older people there seems to be no relationship between how well they do on tests of their mental ability and thinking memory skills and how satisfied they are with their life,” said Alan Gow, of the University of Edinburgh in Scotland. The study, which is published in the British Medical Journal, looked at how people maintain their mental ability as they age and the impact it has on their lives in an effort to discover the secret of successful ageing.
— Reuters Parasite genomes Three parasites that sicken or kill millions of people in the developing world every year have been genetically sequenced and are giving up clues that could be used to fight them, scientists said. The international team said they had mapped out the genomes of the parasites that cause African sleeping sickness, Chagas disease and leishmaniasis, which kill 150,000 people a year and cripple many more. They found a “common core” of genes that ties the three together and might pave the way for the development of new drugs or vaccines.
— Reuters |
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PROF YASH PAL KINDLY tell me why, in an atom, the negatively charged electron collapse into the positively charged nucleus? Is this in any way similar to the reason why planets do not crash into the Sun under the pull of gravity? Let us first talk about the planets and the sun. You know that our earth, a planet, goes around the sun in a nearly circular path. This is what gives us the measure of a year. If I were to speak in everyday language I would say that the earth, in the absence of the sun would like to keep going in a straight line, but the pull of gravity between the earth and the sun keeps bending its path in such a way that it becomes a circle. I could also say that the orbit of the earth around the sun, including its period and distance from the earth is determined by the balance of the force of gravity and a centrifugal force due to its circular motion. When the great scientist Neils Bohr first gave a model of hydrogen atom he started by balancing the electrical attraction between an orbiting electron and a proton. Unfortunately another consideration came in the way of getting a stable system. It was realised that an electron circulating around the proton would lose energy precisely because it was being made to go in a circle. This comes from the fact that the force of electric interaction is very different from that of gravity — it is much stronger. I used the word unfortunately a while ago. This is wrong because fortunately it is this consideration that introduced the idea of stable orbits to be defined through considerations that become important at atomic distances and lead to quantum effects. Though the initial theory of atomic structure borrowed from ideas inspired by planetary orbits it became somewhat different as it developed. The people often talk about diamond size in terms of carats. We also talk of 24, 22 or 18 carat gold. What is a carat in these two cases? You are right that when we use the word carat for a diamond we are talking of its size, more precisely of its weight. A five-carat diamond weighs 1gm. In other words in the diamond world a carat is just 200 milligram. On the other hand for gold carat defines the purity of gold. 24 carat gold is pure gold. 18 carat gold will be an alloy in which only 18 parts by weight is gold, the rest being copper or other metals. For much of fabricated items like jewellery some alloying is considered necessary for providing some stiffness and hence the gold used is only 22 carat or, for industrially produced jewelry, even 18. If we have two equal blocks of ice, one at -200°C and at -20°C, and bring them together to room temperature, which one will melt first? Unless this is trick question, the obvious answer would be that the one that is warmer, meaning closer to the melting point, would melt first. The colder block would require some additional heat to raise its temperature to 00 degrees where
melting occurs. |
If solar energy could provide the cooling load requirements, heating load during winter would be automatically covered which would be much smaller in comparison.
ORCA-whale and dolphin mothers and their newborns appear not to sleep for a month after the pups’ birth, researchers report. Neither parent nor offspring shows any ill effects from the long waking stint, and the animals don’t later compensate with extra sleep.