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Roads from plastic waste
‘Talking therapy’ in pregnancy Prof Yash
Pal THIS UNIVERSE |
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Roads from plastic waste
Plastic
is everywhere in today’s lifestyle. It’s used for packaging, protecting, serving, and even disposing of all kinds of consumer goods. Through industrial revolution mass production of goods started and plastic seemed to be a cheaper and effective raw material. Today, every vital sector of the economy starting from agriculture to packaging, automobile, building construction, communication or infotech has been virtually revolutionised by the applications of plastics. Use of this non-biodegradable (according to recent studies, plastics can stay as long as 4500 years on earth) product is growing rapidly and the problem is what to do with plastic-waste. Studies have linked the improper disposal of plastic to problems as distant as breast cancer, reproductive problems in humans and animals, genital abnormalities and even a decline in human sperm count and quality. If a ban is put on the use of plastics on emotional grounds, the real cost would be much higher, the inconvenience much more, the chances of damage or contamination much greater. The risks to the family health and safety would increase and, above all the environmental burden would be manifold. Hence the question is not ‘Plastics vs No Plastics’ but it is more concerned with the judicious use and re-use of plastic-waste. Plastic use in road construction is not new. It is already in use as PVC or HDPE pipe mat crossings built by cabling together PVC (polyvinyl chloride) or HDPE (high-density poly-ethylene) pipes to form plastic mats. The plastic roads include transition mats to ease the passage of tyres up to and down from the crossing. Both options help protect wetland haul roads from rutting by distributing the load across the surface. But the use of plastic-waste has been a concern for scientists and engineers for a quite long time. Recent studies in this direction have shown some hope in terms of using plastic-waste in road construction i.e., Plastic roads. A Bangalore-based firm, K K Poly-flex and a team of engineers from R V College of Engineering, Bangalore, have developed a way of using plastic waste for road construction. An initial study was conducted in 1997 by the team to test for strength and durability. Plastic roads mainly use plastic carry-bags, disposable cups and PET bottles that are collected from garbage dumps as an important ingredient of the construction material. When mixed with hot bitumen, plastics melt to form an oily coat over the aggregate and the mixture is laid on the road surface like a normal tar road. Use of shredded plastic waste acts as a strong “binding agent” for tar making the asphalt last long. By mixing plastic with bitumen the ability of the bitumen to withstand high temperature increases. The plastic waste is melted and mixed with bitumen in a particular ratio. Normally, blending takes place when temperature reaches 45.5° C but when plastic is mixed, it remains stable even at 55° C. The durability of the roads laid out with shredded plastic waste is much more compared with those asphalted with the ordinary mix. Roads laid with plastic waste mix are found to be better than the conventional ones. The binding property of plastic makes the road last longer besides giving added strength to withstand more loads. While a normal “highway quality” road lasts four to five years it is claimed that plastic-bitumen roads can last up to 10 years. Rainwater will not seep through because of the plastic in the tar. So, this technology will result in lesser road repairs. And as each km of road with an average width requires over two tonnes of polyblend, using plastic will help reduce non-biodegradable waste. The cost of plastic road construction may be slightly higher compared to the conventional method. However, this should not deter the adoption of the technology as the benefits are much higher than the cost. Plastic roads would be a boon for India’s hot and extremely humid climate, where temperatures frequently cross 50° C and torrential rains create havoc, leaving most of the roads with big potholes. Already, a kilometre-long test-track has been tested in Karnataka using this technology. The government is keen on encouraging the setting up of small plants for mixing waste plastic and bitumen for road construction. It is hoped that in near future we will have strong, durable and eco-friendly roads which will relieve the earth from all type of plastic-waste. The writer is from Department of Physics, Sant Longowal Institute of Engineering and Technology, Longowal. |
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‘Talking therapy’ in pregnancy A form of “talking therapy” has restored the fertility of women who would otherwise need drugs and hormone treatment to have a baby. The scientists behind the research believe that psychological therapy that involves talking about a person’s problems could help to boost the fertility of women who find it difficult to conceive as a result of the stress of modern life. A study has shown that cognitive behavioural therapy — which emphasises the role of thinking about how a person feels — can significantly increase the chances of ovulation in a woman suffering from infertility. The therapy involves identifying how negative thoughts affect someone and then looks at ways at tackling or challenging those thoughts in a positive and constructive manner. The research was carried out on 16 women suffering from a condition called functional hypothalamic amenorrhoea, when women of normal weight have not had a menstrual period of six months or more. Up to one in 10 women can suffer this extreme form of amenoorhoea but far more could be subfertile due the influence of stress, said Prof Sarah Berga of Emory University in Atlanta, Georgia. The condition is caused by a prolonged reduction in a hormone produced in the brain which should stimulate the release of further hormones into the bloodstream that trigger the ovaries to ovulate. The women also have high levels of the stress hormone cortisol. “It’s caused by a failure of the brain message to get to the ovary. It’s as if the brain doesn’t care,” Professor Berga said. Women living a stressful life tend to compensate by dieting or undertaking vigorous exercise, which can lead to loss of weight and anovulation — the failure to ovulate. “Up till now it was thought that failure to ovulate was usually caused by the energy deficits induced by excessive exercise and, or under nutrition, but we asked why women undertake such behaviours,” Professor Berga said. “Often dieting and exercise are a way of coping with psychosocial stress, and our previous work had shown that such stress is often increased in women who do not ovulate,” she said. “We think there are women with sub-clinical forms of stress that appear to ovulate but do not get pregnant. It is possible that reducing stress could benefit them and it could also benefit men,” Professor Berg said. In a pilot study, the scientists divided 16 women with the functional hypothalamic amenorrhoea into two groups. One took part in cognitive behavioural therapy for 20 weeks while the other, untreated group were simply observed. — By arrangement with The Independent, London
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THIS UNIVERSE If mass can be converted into energy, it might be possible that energy can be converted into mass by an unknown process. Our Puranas too say that at first there was energy and mass came into existence later. Your long question can be answered rather simply. Since mass and energy are just different forms of the same thing, the back and forth conversion depends only on other conservation laws - other than conservation of energy and momentum. Remember that energy also resides in fields, including the gravitational field. The processes through which energy is converted into mass and vice-versa are fairly well known. I must say I do not believe that the Puranas or any other old religious books have any impact on any of this. Often, the truths in these religious texts are “discovered” after they become manifest through detailed secular endeavour. Water is colourless, water vapour is colourless. Then why are the clouds white or black and not colourless? You must have noticed that clouds are not only white or black; at sunrise or sunset, they are also pink and red. This is because the colour of the cloud is dominated by the light that is scattered from the surface of a large number of tiny droplets. That colour is the same as that of the light falling on them. During the day when the sun is up, it is the scattered light that filters through after many scatterings off water droplets. This makes the clouds white. When the sky is almost covered with thick clouds, little of the scattered light from the cloud comes down while the part of the sky not covered with clouds is bright. This makes the clouds look dark. Dark is after all nothing but an absence of light. You might also think of the colour of the fine spray that is often seen near high waterfalls or tall fountains. That is also white or, when the fountain has changing muticoloured lights, the same colour as that of the lighting of the moment. I could also draw your attention to the whiteness of the foam on an agitated pool of soap water. |
