Science And Technology Update TheHindu

Carbon-dioxide emissions at all-time high in 2013

 

4.2 % rise in India’s discharge of the greenhouse gas: study

Global carbon-dioxide emissions from burning of fossil fuels and production of cement reached a high of 35.3 billion tonnes in 2013, mainly due to the continuing steady increase in energy use in emerging economies such as India, a new report says.

Brazil (6.2 per cent), India (4.4 per cent), China (4.2 per cent) and Indonesia (2.3 per cent) reported a sharp rise in emissions of the greenhouse gas that year.

The global emissions, however, increased at a notably slower rate of 2 per cent than the average yearly 3.8 per cent since 2003. The slowdown, which began in 2012, signals a further decoupling of global emissions and economic growth, mainly reflecting the lower emissions growth rate of China, says the annual “Trends in global CO emissions” released by the Netherlands Environmental Assessment Agency and the European Commission’s Joint Research Centre.

The top three

China, the United States and the European Union remain the top three emitters of carbon dioxide, accounting for 29 per cent, 15 per cent and 11 per cent, respectively, of the world’s total. After years of a steady decline, the emissions of the gas by the U.S. grew by 2.5 per cent in 2013, mainly due to a shift in power production from gas back to coal and an increase in gas consumption for space heating, the report says.

In the European Union, emissions continued to fall — by 1.4 per cent in 2013.

The much lower increase in emissions in China — 4.2 per cent in 2013 and 3.4 per cent in 2012 — was primarily due to a decline in electricity and fuel demand from the basic materials industry, and aided by an increase in renewable energy and improvements in energy efficiency.

“With the present annual growth rate, China has returned to the lower annual growth rates that it experienced before its economic growth started to accelerate in 2003, when its annual carbon dioxide emissions increased on average by 12 per cent a year,” the report says.

GSLV Mark III takes to the skies in test flight

ISRO takes a step towards manned space flight

The first experimental flight of the Geosynchronous Satellite Launch Vehicle (GSLV) Mark III registered success as it lifted off from the second launch pad at the Satish Dhawan Space Centre in Sriharikota on the dot at 9.30 a.m. on Thursday, taking India much closer to realising the dream of manned space flight.

The mission control centre erupted in smiles and claps and the scientists hugged each other, as the GSLV Mark III moved a step closer to its first development flight with the functional C25 cryogenic stage.

Also known as LVM3/CARE, the suborbital experimental mission was intended to test the vehicle’s performance during the critical atmospheric phase of its flight and this carried a passive (non-functional) cryogenic upper stage.

The vehicle, exactly five-and-a-half minutes after take-off, carried its payload — the 3,775-kg crew-module atmospheric re-entry experiment (CARE) — to the intended height of 126 km. Two massive S-200 solid strap-on boosters, each carrying 207 tonnes of solid propellants, ignited at lift-off and separated 153.5 seconds later. The L110 liquid stage ignited 120 seconds after lift-off.

“This new launch vehicle performed very well and was a great success. We had an unmanned crew module to understand re-entry characteristics. That went off successfully and the crew module splashed as expected in the Bay of Bengal,” said Indian Space Research Organisation Chairman K. Radhakrishnan from the mission control centre.

With the module gently landing in the Andaman Sea, about 1,600 km from Sriharikota, the GSLV Mk-III X/CARE mission concluded successfully. “As it made its way back into our atmosphere, the parachutes performed as per the speed that we expected,” said S. Unnikrishnan Nair, Project Director, Human Spaceflight Programme.

The former ISRO Chairman K. Kasturirangan, who was present, said, “ Every GSLV should go higher not only physically, but mentally too.”

Valuable spin-offs from carbon nanotube research

With the sophisticated computerisation of the instrument, the measurements can be done in a fully programmable and controlled manner.

Irrespective of its goal, a scientific research project may sometimes throw up gifts for the researcher that are worth being showcased as well. This is what has happened in the case of Piyush Jagtap, research scholar at Indian Institute of Science’s (IISc) Department of Materials Engineering, who found not one, but two such gifts. One, the invention of a device to measure changes in material property as it moves through an electric field and two, the discovery that carbon nanotube foam can form an effective smart shock absorber in devices such as cell phones.

Guided by his thesis adviser, Dr. Praveen Kumar, Piyush’s research into the properties of carbon nanotubules in an electric field led him to build up, from scratch, an instrument to study the properties of small objects moving in an electric field and also develop the methodology to analyse the measurements.

With the sophisticated computerisation of the instrument, the measurements can be done in a fully programmable and controlled manner. For instance, they can study what happens when the electric field is increased in a pre-programmed way or is switched off while loading and switched on while unloading, or any complicated sequence that is desired. Before they built up this device, there existed no other way of executing this task.

Second spin-off

One of the first things the researchers did was to study the mechanical properties of carbon nanotube foam. They found that the shock-absorbent properties of this material actually get enhanced when it is subjected to an electric field. “If subjected to an electric field of 2 volt per millimetre length of the material, its shock-absorbent properties are enhanced six to seven times,” says Dr. Praveen Kumar. This is good news, for it conveys that carbon nanotube foam would make a good inclusion in mobile phones and such small devices as a shock absorber — smart shock absorber is the word for it. Such shock absorbers become particularly relevant and important as the electronics inside mobile devices such as phones and tablets are becoming increasingly fragile with miniaturisation and increasing current density (electric current per unit area).

The duo is the first to have studied this behaviour, especially because such a device for measuring the effect of a field on a small moving item never existed earlier.

“Developing the instrument took us about four to five months, but we had spent more than a year thinking about the larger problem — the mechanical behaviour of the response of carbon nanotubes in an electric field,” says Dr. Kumar, adding that this work will further pave the way to exploration and collaborations to study different materials.

Taj: the pollutants causing discolouration identified

Particulate carbon and fine dust particles cause browning of the marble

Finally, the specific pollutants in the air that are responsible for the discolouration of the white marble of Taj Mahal have been identified. Particulate carbon and fine dust particles that are deposited on the marble are responsible for its browning.

Carbon is of two types — black carbon and light absorbing organic carbon or brown carbon. The results from a study were published a few days ago in the journal Environmental Science & Technology.

Besides studying air samples collected from the area, the authors used marble samples on the building to collect the pollutants. They also undertook computer modelling to study the colour change brought about by reflectance of the particles.

Both organic carbon and dust particles have the ability to preferentially absorb light in the blue region of the spectrum. The absorption of blue light by these pollutants in turn gives the marble surface a brown hue.

“There is one group of organic carbon which absorbs light in the blue region of the spectrum and this is called brown carbon. Discolouration is because of what is happening to reflectance, and reflectance is in turn influenced by these particles,” said Prof. S.N. Tripathi from the Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology (IIT), Kanpur. He is one of the authors of the paper.

Role of dust particles

The ability of fine dust particles to produce the brown hue is a well known in North India. According to him, it is the presence of haematite in the dust that is responsible for the brown hue.

“If haematite is not present in the dust then the dust would be only scattering in nature,” he said. Haematite is the ingredient that absorbs the blue wavelength of the spectrum.

Though the absorption of blue light by individual dust particles may be smaller than that by brown carbon, the copious amount of dust of two micron size found in the particulate matter makes the overall absorption much higher than that by brown carbon.

The study revealed that particles larger than two micron in size accounted for nearly 70 per cent of the deposited particle surface area. These relatively coarse particles are by default the dust particles.

Pure dust particles per se do not have the ability to stick to surfaces. “But what we see is a potpourri of particles. The organic carbon is very sticky,” Prof. Tripathy said. Unlike the dust particles, carbon particles are in the 100 nanometre to 1 micron size. Burning of biomass like wood and dung, burning of trash and crop residue are the primary sources of brown and black carbon.

On studying the marble samples, the researchers found that black carbon produces a greyish discolouration, while brown carbon and dust produce yellowish-brown hues.

A combination of these two result in darker shades of yellow-brown. The sample targets were in place only for a brief period of two months.

“We found the colour of surrogate marbles matched well with model results. Modelling showed the combined effect of dust and carbon in discolouration of the marble samples,” he said.

Special care for children during medical radiation procedures

Children less than 10 years of age are much more radiation sensitive than middle-aged adults as they have more rapidly dividing cells

The use of ionising radiation in medicine saves lives. However, physicians must take care in using this double-edged sword. They must be especially careful when they carry out medical X-ray procedures on children. This is particularly important during procedures such as CT scans which deliver high radiation doses.

They must avoid unnecessary medical X-ray exposure. More so, when the patient is a child as it is at relatively greater risk than adults are. They must justify every radiation procedure.

From the publication No 121 titled “Radiological protection in paediatric diagnostic and interventional radiology,” from the International Commission on Radiological Protection (ICRP), the latest issue of the AERB Newsletter (Vol 27,No 1, 2014), listed the following nine radiological practices as unjustified:

Skull radiograph in an infant or child with epilepsy; skull radiograph in an infant or child with headaches; sinus radiograph in an infant or child under 6 years of age; suspected of having sinusitis; cervical spine radiograph in an infant or child with torticollis without trauma; radiographs of the opposite side for comparison in limb injury; scaphoid radiographs in children under 6 years of age; nasal bone radiographs in children under 3 years of age; routine daily chest examination in intensive care units and radiological examinations requested purely for medico-legal purposes.

Children have more rapidly dividing cells than adults. They have longer life expectancy. The US National Research Council’s Committee on Biological Effects of ionising Radiation has noted that children less than 10 years of age are several times more radiation sensitive than middle-aged adults.

The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in its report titled “Effects of radiation exposure of children” states that the radiation doses received by children and adults from the same source of ionising radiation can have differing impacts, and therefore, should be considered separately in order to predict risk following exposure more accurately for children (UNSCEAR, October 24, 2013).

The Committee reviewed 23 different cancer types. For over 25 per cent of these cancer types including leukaemia and thyroid, brain and breast cancer, children are found to be more sensitive than adults. Cancer risk is not always immediate but extends later into life. Some of the cancers are highly relevant to assess the radiological consequences of nuclear accidents and some medical procedures. The need to implement paediatric protocols for diagnostic radiation procedures is obvious.

Recently, physicians in U.S. and Canada decided to select appropriate protocols in paediatric nuclear medicine. Health effects depend on many physical factors. For instance, for internal exposure to radiation, there are differences in the doses received by children and adults from exposure to the same distribution of radioactive material.

As infants and children have smaller body diameters, and their organs are less shielded by overlying tissues, the doses to their internal organs are higher than that to an adult for the same exposure. Metabolism and physiology vary with age; this also affects the concentrations of radio-nuclides in different organs and thus the dose to those organs for a given intake.

Infants and children can receive significantly higher doses than adults in medical exposure if the technicians do not adjust the technical settings appropriately. When a CT scan is carried out on a child with the same technique factors that are typically used for an adult, the child receives significantly higher dose than the adult. Regrettably, this happens very often.

While carrying out an AERB-funded safety research project, researchers from the Christian Medical College (CMC) Vellore noted that of the 71 CT Units surveyed, 32 did not use paediatric protocols. They also observed that 8.9 per cent of CT scans are on children. Evidently, substantial numbers of CT equipment expose children to needlessly high radiation doses.

The same researchers, who studied 127 CT scan units, found that there is a wider variability of doses with protocols varying in each centre. For instance, for a routine abdomen study, the doses ranged from 1.6 mSv to 20.6 mSv, for thorax it ranged from 1.9 mSv to 24.9 mSv. For certain other examinations, they found that the maximum dose was very high.

The website of the Alliance for Radiation Safety in Pediatric Imaging (www.imagegently.org) is a rich resource of information for all, including parents.

In spite of many deficiencies, physicians must not refuse a clinically required X-ray examination as the potential risk from such exposure will be relatively small compared to its direct benefit. They must keep abreast with the recommendations of competent professional agencies such the WHO and the ICRP on acceptable referral criteria for diagnostic radiation procedures. Professional associations must standardise the radiation procedures. AERB which is mandated to protect patients must extend all assistance to such associations.

How Mars lost its atmosphere decoded

Early discoveries by NASA’s newest Mars orbiter have unveiled key features about the loss of the Red Planet’s atmosphere to space over time, researchers say.

The findings are among the first returns from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission, which entered its science phase on November 16.

The observations show a new process by which the solar wind can penetrate deep into a planetary atmosphere.

They include the first comprehensive measurements of the composition of Mars’ upper atmosphere and electrically charged ionosphere.

The results also offer an unprecedented view of ions as they gain the energy that will lead to their escape from the atmosphere.

“We are beginning to see the links in a chain that begins with solar-driven processes acting on gas in the upper atmosphere and leads to atmospheric loss,” said Bruce Jakosky, MAVEN principal investigator with the Laboratory for Atmospheric and Space Physics at the University of Colorado.

“Over the course of the full mission, we’ll be able to fill in this picture and really understand the processes by which the atmosphere changed over time,” Mr. Jakosky said.

On each orbit around Mars, MAVEN dips into the ionosphere — the layer of ions and electrons extending from about 75 to 300 miles above the surface.

This layer serves as a kind of shield around the planet, deflecting the solar wind, an intense stream of hot, high-energy particles from the Sun, researchers said.

Scientists have long thought that measurements of the solar wind could be made only before these particles hit the invisible boundary of the ionosphere.

MAVEN’s Solar Wind Ion Analyser, however, has discovered a stream of solar-wind particles that are not deflected but penetrate deep into Mars’ upper atmosphere and ionosphere.

New insight into how gases leave the atmosphere is being provided by the spacecraft’s Supra-thermal and Thermal Ion Composition (STATIC) instrument.

Within hours after being turned on at Mars, STATIC detected the “polar plume” of ions escaping from Mars. This measurement is important in determining the rate of atmospheric loss.

As the satellite dips down into the atmosphere, STATIC identifies the cold ionosphere at closest approach and subsequently measures the heating of this charged gas to escape velocities as MAVEN rises in altitude.

The energised ions ultimately break free of the planet’s gravity as they move along a plume that extends behind Mars.

A new lease of life for medicinal plants

Increase in life expectancy more in women in India

A Global Burden of Disease Study 2013 published today (December 18) in the journal The Lancetpoints out that in the case of India, the life expectancy at birth during the period 1990 to 2013 had increased for both men and women.

In the case of men, the increase in life expectancy was from 57.3 to 64.2 years and in the case of women, it was from 58.2 to 68.5 years between 1990 and 2013. The reduction in death rate was seen both in adults and children. Though the death rate per year witnessed a drop both in adults and children, it was more in the case of children than adults. At 3.7 per cent, the death rate reduction per year in children was much more than that of adults, which was at 1.3 per cent.

According to the report, ischemic heart disease was the number one cause of death in India in 2013. The other leading causes (in descending order) were lower respiratory track infections, tuberculosis, neonatal encephalitis, preterm birth complications, diarrhoea, stroke, chronic obstructive pulmonary disease (COPD), suicide, and finally road injuries.

“COPD is caused due to lung damage. Smoking is one of the causes of COPD. But in the case of women in India, COPD is more due to indoor pollution than smoking. Even TB could be an important cause,” Dr. Soumya Swaminathan, Director of the Chennai-based National Institute for Research in Tuberculosis (NIRT) told this Correspondent. While TB is the number three cause, diarrhoea is way down at the sixth position. Referring to this, Dr. Swaminathan said: “That shows that interventions for diarrhoea have really worked and reduced the number of deaths, while in the case of TB the interventions have been less effective in reducing deaths. This is despite RNTCP being effective and bringing about 20 per cent reduction in TB deaths in India.”Across the world, deaths from diarrhoeal diseases between 2000 and 2013 fell by about 31 per cent.

Though there has been much reduction in the number of deaths in under-five children across the world and in India, lower respiratory track infections and diarrhoea are two of the three causes seen in India. But other causes like neonatal encephalitis and preterm birth complications that affect children continue to be major causes of death in India. Globally, neonatal deaths fell significantly since 2000.

Half of all suicide deaths that occur in the world are in India and China. “Suicide is a major and growing public health problem in India,” notes a release. What is of great concern is that though India and China account for half of global suicide deaths, the number of suicides was reducing “rapidly” in China while it was “rising” in India during the period 1990-2013. “Both countries have undergone economic growth and urbanisation, a key factor in limiting access to lethal pesticides, a common method of suicide by poisoning in both countries. Therefore, as yet unexplained reasons must exist for the divergence between the two countries,” the paper notes.

What becomes abundantly clear is that ischemic heart disease is the only lifestyle disease in the top ten causes of deaths in India. This is in complete variance with what is seen in the developed countries.

The Kerala State Biodiversity Board (KSBB) has launched a project ‘resource conservation, augmentation, sustainable harvesting and value addition of medicinal plants resources’ to conserve the critically endangered medicinal plants in the Western Ghats region.

The project implemented with financial assistance of the National Medicinal Plant Board also aims at ensuring sustainable income to the tribal people who earn their livelihood collecting minor forest produces.

The project will be executed in association with the biodiversity management committees functioning at the grama panchayat level and the Forest Department.

Conservation

The project aims at conserving the critically endangered medicinal plant species, S. Rajasekharan, senior programme coordinator of the KSBB, told The Hindu.

Minor forest produces such as Kurmthotti (Sida alnifolia); Nellikka (Phyllanthus emblica), Thanika (Terminalia bellirica), and Moovila (Pseudarthria viscida) would be collected and processed under the project, Dr. Rajasehkaran said.

Value-added products

He said the KBB was planning to make value-added products from medicinal plants and improve the standard of living of the tribesmen engaged in collecting minor forest produces, Dr. Rajasehkaran said.

The project would be executed at an estimate of Rs.50 lakh at Thavinhal, Thurnelly, Moopainad, Poothadi, and Noolpuzha grama panchayats in the district in the initial phase and would be expanded to other grama panchayats in the State later. North Wayanad divisional forest officer Narendranath Veluri inaugurated the programme at Mananthavady on Tuesday.