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

Five things to know about Isro's GSLV Mark III mission

The Indian Space Research Organisation (Isro) will launch its first experimental suborbital flight today. 

This will be the test launch for Isro's heaviest and upgraded rocket, the GSLV - Mark III, which is carrying the Crew Module Atmospheric Re-entry Experiment (CARE).

The flight will take off from Isro's space station Sriharikotta, near Chennai. Here are five things you need to know about the GSLV - Mark III mission.

1) After its successful Mars mission, this is Isro's next step to put a man in space

2) The Rs 155 crore mission has twin purposes -- the main purpose is to test the rocket’s atmospheric flight stability with around 4-tonne luggage. The second is to study the re-entry characteristics of the crew module called Crew Module Atmospheric Re-entry Experiment.

3) Other critical technologies are also to be developed for Isro's manned mission. These are being developed parallelly at other centres. But recovery of the capsule from out of atmosphere will be the first to be tested. 

4) GSLV Mark III is the heaviest next generation rocket, conceived and designed to make Isro self reliant in launching heavier communication satellites of INSAT-4 class, which weigh 4,500 to 5,000 kg. Once operational, this rocket will have the capability to ferry four-tonne class of Insat series of communication satellites, which are currently being launched through Arianespace.

5) This is the second mission of the GSLV rocket during the last four years after two such launches failed in 2010.

ISRO launches India’s biggest rocket GSLV Mark III from Sriharikota -

This summary is not available. Please click here to view the post.

Historic thaw in U.S.-Cuba relations announced

As part of the secret negotiations to secure his release, the U.S. was releasing three Cubans jailed in Florida for spying.

The United States and Cuba on Wednesday agreed to re-establish diplomatic relations and open economic and travel ties, marking a historic shift in U.S. policy towards the island after a half-century of enmity dating back to the Cold War.

The announcement came amid a series of sudden confidence-building measures between the long-time foes, including the release of American prisoner Alan Gross, as well as a swap for a U.S. intelligence asset held in Cuba and the freeing of three Cubans jailed in the U.S. Gross arrived at Andrews Air Force Base outside Washington.

President Barack Obama and Cuban President Raul Castro were to separately address their nations around noon. The two leaders spoke by phone for more than 45 minutes Tuesday, the first substantive presidential-level discussion between the U.S. and Cuba since 1961.

Wednesday’s announcements followed more than a year of secret talks between U.S. and Cuban officials in Canada and the Vatican. U.S. officials said Pope Francis was personally engaged in the process and sent separate letters to Obama and Castro this summer urging them to restart relations.

Officials spoke on the condition of anonymity because they were not authorized to discuss the matter publicly ahead of Obama’s remarks.

Gross, 65, arrived back in the U.S. shortly before Obama was to address the nation. Gross was released after more than five years in prison. He was accompanied by his wife, Judy, along with several U.S. lawmakers.

As part of resuming diplomatic relations with Cuba, the U.S. will soon reopen an embassy in the capital of Havana and carry out high-level exchanges and visits between the governments. The U.S. is also easing travel bans to Cuba, including for family visits, official U.S. government business and educational activities. Tourist travel remains banned.

Licensed American travelers to Cuba will now be able to return to the U.S. with $400 in Cuban goods, including tobacco and alcohol products worth less than $100 combined. This means the long-standing ban on importing Cuban cigars is over, although there are still limits.

The U.S. is also increasing the amount of money Americans can send to Cubans from $500 to $2,000 per quarter, or every three months. Early in his presidency, Obama allowed unlimited family visits by Cuban-Americans and removed a $1,200 annual cap on remittances. Secretary of State John Kerry is also launching a review of Cuba’s designation as a state sponsor of terror.

Obama does not have the authority to fully lift the long—standing U.S. economic embargo on Cuba, given that Congress enacted that policy. However, officials said he would welcome lawmakers taking that step.

There remains a divide on Capitol Hill over U.S. policy toward Cuba. While some lawmakers say the embargo is outdated, others say it’s necessary as long as Cuba refuses to reform its political system and improve its human rights record.

Sen. Marco Rubio, R-Florida, said the policy Obama was to announce on Wednesday did nothing to address those issues.

“But it potentially goes a long way in providing the economic lift that the Castro regime needs to become permanent fixtures in Cuba for generations to come,” Rubio said.

U.S. officials said Cuba was taking some steps as part of the agreement to address its human rights issues, including freeing 53 political prisoners.

Cuba was also releasing a non-American U.S. intelligence ‘asset’ along with Gross. Officials said the spy had been held for nearly 20 years and was responsible for some of the most important counterintelligence prosecutions that the United States has pursed in recent decades. That includes convicted Cuban spies Ana Belen Montes, Walter Kendall Myers and Gwendolyn Myers and a group known as the Cuban Five.

The three Cubans released in exchange for the spy are part of the Cuban Five a group of men who were part of the “Wasp Network” sent by Cuba’s then-President Fidel Castro to spy in South Florida. The men, who are hailed as heroes in Cuba, were convicted in 2001 in Miami on charges including conspiracy and failure to register as foreign agents in the U.S.

Two of the Cuban Five were previously released after finishing their sentences.

Gross was detained in December 2009 while working to set up Internet access as a subcontractor for the U.S. government’s U.S. Agency for International Development, which does work promoting democracy in the communist country. It was his fifth trip to Cuba to work with Jewish communities on setting up Internet access that bypassed local censorship.

Bonnie Rubinstein, Gross’ sister, heard the news from a cousin, who saw it on television.

“We’re like screaming and jumping up and down,” she said in a brief telephone interview from her home in Texas.

Cuba considers USAID’s programs illegal attempts by the U.S. to undermine its government, and Gross was tried and sentenced to 15 years in prison.

Gross’ family has said he was in ailing health. His wife, Judy, said in a statement earlier this month that Gross has lost more than 100 pounds 45 kilograms), can barely walk due to chronic pain, and has lost five teeth and much of the sight in his right eye.

Obama has taken some steps to ease U.S. restrictions on Cuba after Raul Castro took over as president in 2010 from his ailing brother. He has sought to ease travel and financial restrictions on Americans with family in Cuba, but has resisted calls to drop the embargo.

Microsoft pitches for ‘White-Fi’to provide last mile connectivity

Other countries where Microsoft has helped implement the technology are Kenya, Singapore, the U.S. and London.

Microsoft is looking at starting a pilot project of its ‘White-Fi’ technology that uses the unused spectrum in frequencies used for broadcasting of television signals, and is likely to offer solution to tackle the problem of last mile broadband connectivity in the country.

“In a country of massive change, digital divide can pose serious challenge. In all the initiatives by the government — Digital India, Swachh Bharat or Jan-Dhan Yojna — technology has a role to play, and we want to be part of it,” Microsoft India Chairman Bhaskar Pramanik said, adding that at present, the company was talking to all stakeholders, including the government, for its ‘White-Fi’ technology to provide last mile connectivity.

“We are waiting for licence to start our pilot of the technology. Where ever spectrum is involved government permission in needed… We will start with IIIT, Bangalore. We may start with the campus, but want to take it to rural areas to see how it works with all natural barriers,” he added.

The pilot, once started, is expected to last for about three months. Other countries where Microsoft has helped implement the technology are Kenya, Singapore, the U.S. and London.

The 200-600 MHz frequency is used for TV channels to carry data. In India, 93 per cent of this spectrum is not utilised.

‘White-Fi’ will use this vacant spectrum to provide connectivity.

In technology parlance, these unused spectrum spaces are called White Space, and many technology companies are looking at using this to provide free last mile internet access to users.

Under the ‘Digital India’ initiative, the government plans to use the national optic fibre network project to deliver e-services to all corner of the country.

While this network will be deployed at the gram panchayat level, reaching the end consumer may still require wireless technology, particularly in far flung areas.

U.S.-Cuba ties: From revolution and Bay of Pigs to rapprochement

A summary of U.S.-Cuba relations since Fidel Castro seized power in a 1959 revolution

The United States and Cuba plan to restore diplomatic relations and end more than five decades of fierce animosity that at one point took the world to the edge of nuclear conflict.

Here is a summary of U.S.-Cuba relations since Fidel Castro seized power in a 1959 revolution:

Jan. 1, 1959: Cuban Revolution. Castro and his rebel army take power after U.S.-backed former dictator Fulgencio Batista flees island.

June 29, 1960: United States suspends Cuban sugar import quota after Castro nationalizes Texaco refinery.

Oct. 19, 1960: United States begins partial economic embargo against Cuba.

Jan. 3, 1961: Washington breaks diplomatic ties with Cuba.

April 19, 1961: Castro's troops defeat CIA-backed Cuban exile invasion force at Bay of Pigs.

Jan. 22, 1962: At U.S. urging, the Organization of American States (OAS) suspends Cuba.

Feb. 7, 1962: Full U.S. trade embargo imposed on Cuba.

October 1962: Cuban Missile Crisis. The presence of Soviet missiles in Cuba provokes standoff between Moscow and Washington. Many fear a world war, but Russia reaches a compromise deal with the United States and withdraws the missiles.

Sept. 1, 1977: Cuba and United States establish informal diplomatic missions, or Interests Sections, in Havana and Washington.

April-September 1980: Mariel Boatlift. Cuba allows mass exodus of about 125,000 citizens to the United States, mostly via Mariel port west of Havana.

March 1, 1982:The U.S. State Department adds Cuba to its list of State Sponsors of Terrorism.

Oct. 23, 1992: U.S. President George Bush signs Torricelli Act to tighten embargo on Havana amid severe economic crisis triggered by Soviet bloc's collapse at start of decade.

Aug. 14, 1993: Havana ends ban on use of U.S. dollars.

August 1994: Rafter Crisis. More than 30,000 Cubans flee island on flimsy boats. Washington and Havana sign immigration accord to stem exodus and agree to a minimum of 20,000 legal entry visas per year for Cubans.

Feb. 24, 1996: Cuba shoots down two civilian planes of the Cuban exile group Brothers to the Rescue, killing four people. Brothers to the Rescue says it was on a humanitarian mission looking for rafters fleeing Cuba. Cuba says they had routinely violated Cuban airspace.

March 1996: Outraged over downing of the planes, U.S. Congress approves Helms-Burton Act, tightening the embargo and requiring a vote of Congress to repeal it. President Bill Clinton, seeking re-election that year, signs the bill into law.

March 20, 1998: Clinton announces renewal of direct passenger charter flights and permission for Cuban-Americans to send remittances to families on island.

January 1998: Pope John Paul visits Cuba, condemning U.S. embargo but also calling for greater freedoms on the island.

Nov. 25, 1999: Elian Gonzalez custody saga starts, when 6-year-old Cuban boy is rescued at sea off U.S. coast after surviving a shipwreck that kills his mother and 10 other Cuban migrants. After a bitter seven-month dispute, which prompted a massive patriotic campaign in Cuba, Elian flies home to Cuba to be with his father.

July 13, 2001: U.S. President George W. Bush orders his administration to more strictly enforce sanctions and pledges increased support for pro-democracy forces on the island.

November 2001: Cuba purchases U.S. agricultural products as the two countries begin their first direct food trade since 1962, under an exception to embargo passed by U.S. Congress.

May 6, 2002: U.S. Undersecretary of State for Arms Control and International Security John Bolton accuses Cuba, along with Libya and Syria, of working to develop biological weapons, a charge Castro denies.

June 30, 2005: New U.S. curbs on travel come into force as Bush administration tightens enforcement of embargo.

July 10, 2006: U.S. government announces increased support for dissidents and more money for anti-Castro broadcasts by Radio and TV Marti.

July 31, 2006: Fidel Castro provisionally cedes power to brother Raul Castro after undergoing surgery for undisclosed intestinal ailment.

Feb. 24, 2008: Raul Castro is elected president by National Assembly, replacing his older brother.

Dec. 3, 2009: Cuba arrests Alan Gross, a U.S. Agency for International Development subcontractor, who had brought banned telecommunications equipment to Cuba and attempted to establish clandestine Internet service for Cuban Jews. He was later sentenced to 15 years in prison.

Jan. 20, 2009: Barack Obama, who has said he wants to take steps toward normalizing relations with Cuba, is sworn in as president. He soon goes on to ease U.S. restrictions on travel and remittances to Cuba.

Nov. 8, 2013: Obama tells a Miami fundraiser, "We have to be creative and we have to be thoughtful and we have to continue to update our policies" on Cuba.

Dec. 14, 2014: Obama announces plan to restore diplomatic relations in major policy shift. Cuba releases Gross as well as an intelligence agent who spied for the United States and had been held in prison for nearly 20 years. In return, Washington releases three Cuban intelligence agents held in the United States. Obama says the United States will open an embassy in Cuba and relax some of the restrictions on commerce and travel between the United States and Cuba.