Easing Atmospheric CO2 Levels Using Nanotubes and Sunlight

first_img(PhysOrg.com) — Researchers at The Pennsylvania State University have determined a way to use arrays of nanotubes in a solar-based process to convert carbon dioxide and water into methane and other hydrocarbon fuels. Their method may provide a new way to reduce carbon-dioxide levels in the atmosphere—rising due to our planet’s heavy use of fossil fuels—as well as produce alternative fuels. The rate of carbon dioxide (CO2) conversion using this method is 20 times higher than that of previously published research. The work is described in the January 27, 2009, online edition of Nano Letters.”Every 12 days the world consumes about one billion barrels of oil, which represents the release of almost 1 trillion pounds of carbon dioxide into the atmosphere,” said the study’s lead researcher, Craig Grimes, to PhysOrg.com. “One way of dealing with this problem is by recycling the CO2 into a high-energy-content fuel, but this makes sense only if a renewable energy source, like solar energy, can be used in the process.”This type of solar-based conversion process only works if a photocatalyst—a material that reacts with light—is used to convert the CO2 into hydrocarbons. A photocatalyst that utilizes the most solar energy possible is the best option.One popular photocatalyst candidate for the job has been titanium dioxide, also called titania, because it can powerfully react with oxygen. But so far, researchers haven’t been able to make titania perform adequately despite experimenting with a variety of forms, such as nanoparticles, pellets, and multi-layer films.Grimes and his colleagues used arrays of titania nanotubes. They created the nanotubes using a technique that incorporates nitrogen into the nanotubes’ structures, which the researchers initially thought would help increase the conversion rate (this turned out to be true only in a very limited capacity).The process also yields a high total surface area compared to other forms of the material, a property that aids in the conversion. To further boost the process, the group scattered an ultra-thin layer of platinum and/or copper “cocatalyst” nanoparticles on the surface of the array.The nanotubes were as long as 140 micrometers (millionths of a meter) in length and a diameter of about 115 nanometers (billionths of a meter). The total size of each array sample was about 2 centimeters square and the group created several samples.The researchers made two reaction chambers, each with a window at the top to let in sunlight. They loaded one sample into each chamber and evacuated the air out, producing a vacuum, and sealed them. Next they pumped CO2 through a tank of water and into the chambers, flushing it through via intake and outtake valves for 10 minutes.This all took place outdoors on sunny or mostly-sunny days on the Penn State campus. The samples were left outside for 2.5 hours, up to a maxiumum of 3.5 hours, between about 12:30 and 4:00 p.m.Analysis of the chambers’ interiors showed that the predominant product of the conversion was methane, with some ethane, propane, butane, pentane, and hexane, along with other materials in very small concentrations. The conversion rates were high, although comparing the results with other published results was rather difficult, according to the group.”Most of the previous results were achieved using nanoparticles illuminated by ultraviolet light, so we were not exactly comparing apples to apples,” said Grimes. “But going by the weight of the material, we could figure out that the rate of hydrocarbon production we achieved is at least 20 times higher than those previous studies.”Grimes and his group attribute their success, in large part, to the cocatalyst particles they used. They think that a homogeneous distribution of both types could further increase the conversion rate.More information: Nano Lett., 2009, 9 (2), pp 731-737 DOI: 10.1021/nl803258pCopyright 2009 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Citation: Easing Atmospheric CO2 Levels Using Nanotubes and Sunlight (2009, February 16) retrieved 18 August 2019 from https://phys.org/news/2009-02-easing-atmospheric-co2-nanotubes-sunlight.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further City dwellers can have an outsized impact on curbing global warming A digital photograph of one of the reaction chambers under natural sunlight. Photo courtesy Craig Grimes.last_img read more

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Pair of noted physicists contemplate future of cosmology after detection of primordial

center_img More information: Next Steps for Cosmology, Science 9 May 2014: Vol. 344 no. 6184 pp. 586-588. DOI: 10.1126/science.1252724AbstractExperiments on the ground, balloons, and satellites have revolutionized our knowledge of the Big Bang by measuring the fossil glow from the first instants of the universe, the cosmic microwave background (CMB) radiation. Infinitesimal fluctuations in the photon temperature have been found, revealing the seeds of all large-scale structures, from galaxies to clusters of galaxies and superclusters. The detected wiggles in the distribution of the temperature fluctuations measure the gravitational coupling between dark matter, baryons, and radiation as the universe emerged from its opaque fireball phase. These measurements, pioneered by the Cosmic Background Explorer (COBE) (1) and then greatly refined by its successors, the Wilkinson Microwave Anisotropy Probe (WMAP) (2) and Planck (3) satellites, have allowed precise determinations of the key parameters of our universe—age, dark matter, dark energy content, and even the number of different types of neutrinos, as well as the strength and distribution of the primordial density fluctuations. Less than two decades ago, it was debated whether the major constituent of the universe, dark energy, even existed. Now its contribution is measured to an accuracy of a few percent. © 2014 Phys.org Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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Researchers offer possible explanation for lack of radiation flash from gas cloud

first_img © 2014 Phys.org Comparison of the pv-diagrams from spring 2013 (data already presented in Gillessen et al. 2013b), late summer 2013 and spring 2014 (new data). The blue line corresponds to the Brackett-γ based orbit from Gillessen et al. (2013b), along which the pv-diagram is extracted. We have blended out the range between −660 km/s and +240 km/s to avoid emission from the mini-spiral (Paumard et al. 2004) visible at these wavelengths. The scaling is adjusted in each map individually to optimally show the structure of the gaseous emission; the maps cannot be compared photometrically to each other. Credit: arXiv:1407.4354 [astro-ph.GA] Journal information: arXiv Explore further The gas cloud, named G2, was first spotted back in 2011, moving towards Sagittarius A*, the super massive black hole believed to exist at the center of our galaxy. Scientists expected a sudden surge in X-rays and radio waves and maybe even a possible brightening of infrared light from the site. Instead, as the gas cloud encountered the black hole, nothing much happened. The cloud simply changed shape a little bit with little to no fanfare, leaving scientists who had trained a lot of telescopes on the Milky Way’s center, feeling let down. In their paper, the researchers in Germany offer a possible explanation regarding why so little appeared to happen.G2, the researchers suggest, is actually part of a continuous stream of material that was ripped from the envelope of a star as recently as just a hundred years ago. They note that G1, another gas cloud spotted over a decade ago, has an identical orbit to G2, and is even in the same plane. They believe both clouds are actually little more than clumps in a much bigger cloud that is essentially a stream of gas that has been traveling towards the center of the Milky Way for a century. And because of that, they suggest, the clumps simply brush Sagittarius A* as they approach and pass by, because of the impact on them exerted by the rest of the stream. If true, it would seem likely that there are other clouds also present in the stream, which are perhaps destined for a rendezvous with Sagittarius A* someday—if so, one of them might produce the fireworks the scientists had been anticipating. (Phys.org) —A team of researchers at the Max Planck Institute in Germany has offered a possible explanation for the lack of fireworks during the interaction between a gas cloud and the black hole believed to be at the center of the Milky Way Galaxy. In their paper uploaded to the prepress server arXiv, the researchers suggest that the expected fireworks didn’t happen because the gas cloud is actually a dense clump that is part of a continuous stream of matter and because of that it only brushed the black hole rather than gushed into it.last_img read more

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Researchers observe inwardly rotating spirals in a nonoscillatory medium

first_img Credit: H. N. Yoshikawa “At a sufficiently high flow-rate, liquid curtains appear, move like waves and, end up coiling around some center point and forming rotating spiral arms,” Mathis explained. “We measured the frequency of rotation of each arm and of the whole pattern and the length of arms. The key observation is the spontaneous formation of spirals through breaking the rotational symmetry of the system.” © 2019 Science X Network Sac with spiral surface patterns facilitate substance delivery Citation: Researchers observe inwardly rotating spirals in a nonoscillatory medium (2019, January 29) retrieved 18 August 2019 from https://phys.org/news/2019-01-inwardly-rotating-spirals-nonoscillatory-medium.html Explore further Journal information: Physical Review Letters A team of researchers at Université Côte d’Azur and Hokkaido University have recently carried out a study exploring the spontaneous formation of spiral patterns observed on the downward-facing free surface of a horizontal liquid film. The surface examined by them entails Rayleigh-Taylor instability, which destabilizes the interface between two fluids of different densities when the heavier fluid is pushing down the lighter one. More information: Harunori N. Yoshikawa et al. Inwardly Rotating Spirals in a Nonoscillatory Medium, Physical Review Letters (2019). DOI: 10.1103/PhysRevLett.122.014502 The researchers observed that the liquid discharge resulting from this instability can occur in the form of propagating liquid curtains, which are generated at the film’s circular periphery and appear as inwardly rotating spiral arms. Using a phenomenologically constructed cellular automaton, they demonstrated that these patterns arise from the phase locking, which leads to an intermittent discharge of liquid at a constant flow rate over the entire film surface. “About 15 years ago, Dr. Laurent Limat and his colleagues studied spatio-temporal dynamics of liquid columns moving freely along the edge of a circular dish,” Christian Mathis, one of the researchers who carried out the present study, told Phys.org. “Inspired by their work, we began the study of a bi-dimensional assembly of liquid columns, hoping to describe all the secondary instabilities related to losses of symmetry. We just found one such instability, but we discovered that we were in front of a rather simple system showing extremely rich behavior.”In their study, Mathis and his colleagues observed that increasing the flow rate gave rise to a series of complex patterns, including a regular hexagonal lattice of drops, a regular hexagonal lattice of columns, spatio-temporally intermittent behavior of columns and, finally, liquid curtains forming spiral waves. The apparatus they used is fairly simple, consisting primarily of a semi-closed cylindrical vessel, with silicone oil continuously pouring into it through an inlet at the top and a fine mesh grid at the bottom. The vessel contains a constant amount of oil, determined by the equilibrium of a negative pressure in the vessel and the weight of the oil. Excessive liquid in the vessel leaks through the grid and forms a liquid film underneath it. This film destabilizes in different ways, depending on the oil flow-rate and viscosity. Inside this apparatus, everything is made of transparent PMMA, as this enables easy observation and precise video measurements with adapted lightning. Spiral patterns can be found in many systems, both in lab experiments and in nature. Most of these spirals patterns rotate, with the spiral arms trailing the direction of this rotation. Patterns that rotate in the opposite direction are quite rare and are referred to as antispirals. “We have shown that antispiral patterns can be produced in a simple liquid system, for which we know all the governing equations,” Harunori Yoshikawa, another researcher who carried out the study, told Phys.org. “Deep investigation of this ‘well-known’ system would provide insights into rare occurrences of antispiral patterns.”The experiment carried out by Yoshikawa, Mathis and their colleagues could pave the way for further studies exploring the manifestation of antispiral patterns. In addition, their study could provide a benchmark for theories of pattern formation. “We are now focusing on theoretical modeling, seeking an appropriate model equation and the ranges of involved parameters,” Yoshikawa said. “We hope that we will theoretically reveal the essential features of these pattern formation processes.”The researchers are also currently exploring other patterns observed in their system, as the inwardly rotating spirals were merely one of their observations. For instance, the dripping regime and some of the peculiar behavior of the liquid columns are yet to be extensively investigated. In the study carried out by Mathis, Yoshikawa and their colleagues, the dynamic of the spirals appeared to be related to the characteristics of the liquid film itself, a finding that they are also looking to explore further. Credit: H. N. Yoshikawa This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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Music in her elements

I dance for myself and not for my audience. Dance is everything for me—be it walking, talking, speaking or living,’ says Shobha Deepak Singh.Shobha started her cultural journey in 1968 when she joined Bhartiya Kala Kendra. Later, she became the first manager of Kamani auditorium. Through script writing, production and direction, she also got involved with the Bhartiya Kala Kendra. ‘I studied at Modern School and graduated in economic from Delhi University in 1963. In 1977, I completed my degree in Bachelor of Performing Arts and a decade and a half later, joined the direction course of Living Theatre, under the tutelage of the legendary E Alkazi. Here, I earned an opportunity for training in production of allied arts such as light and set design and music for plays such as Virasat, Royal Hunt of the Sun, Three Sisters, Three Greek Tragedies, A Streetcar Named Desire and Death of a Salesman. I later worked as an Assistant Director for four productions,’ she explained. Also Read – ‘Playing Jojo was emotionally exhausting’She studied dance under the tutelage of eminent artistes including Shambhu Maharaj and Birju Maharaj and took music lessons from Biswajeet Roy Chowdhary and Amjad Ali Khan.‘Not many know that I am an ardent photographer as well. I possess a rare collection of over 1,00,000 pictures of personalities associated with the performing arts which have been extensively used by leading dailies and magazines. In 1996 and more recently in November 2003, my theatrical photographs were displayed under ‘Art Heritage’, she said. Also Read – Leslie doing new comedy special with Netflix‘I get inspired by reading diverse subjects. Heritage architecture and daily news and happenings are my other pastimes. For me, the process of learning never stops,’ Shobha added. Rechristened as the Iron Lady of Indian Music, Shobha Deepak Singh is currently occupied with her next presentation. Titled Ramlila, she has syncronized the show. ‘I have a cross cultural approach. I have an experience of more than 40 years. Hence, the word boredom doesn’t exist in my dictionary,’ Shobha said. ‘My calendar is busy with successive events. It commences with Janmashtami, when we present ‘Krishna’, followed by Ramlila during Diwali time and then by a musical festival in the month of November,’ she added.Today, as director of the Shriram Bhartiya Kala Kendra, Shobha aspires to take it to exemplary heights.DETAILAt: Kendra Lawns,  1, Copernicus MargWhen: October 15th to November 11thTimings: 6.30 pm to 9.15 pm Phone: 41553037 read more

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Man duped of Rs 1 lakh near Paribesh Bhavan

first_imgKolkata: A person was duped by three other over exchange of US dollars. The incident took place on Tuesday morning in front of Paribesh Bhavan in Salt Lake.According to police, on Tuesday morning a person named Abdul Halim, a resident of Karaya, went to Bidhannagar South police station and informed that he has been cheated of Rs one lakh. He was promised hundred notes of 20 US dollar.According to the complaint filed, Halim had met a person at Chittaranjan National Medical College called Kabil on August 30. Kabil was collecting help stating that he needs money for his father’s heart operation. On hearing this, Halim gave him a hundred rupee note. Also Read – Rain batters Kolkata, cripples normal lifeImmediately after that Bilal took out a 20 US dollar note and asked Halim to exchange it. When Halim asked as to how he got this dollar, Kabil said his father used to work abroad and earned some dollars during his tenure. He added that he has such 100 notes at home at a remote village and would want to exchange all the dollars.Following this Halim took the dollar and exchanged it from Park Street. He handed over Rs 950 to Kabil and his father at the Paribesh Bhavan crossing. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedKabil told Halim that his father’s operation will be done at a hospital in Salt Lake opposite Salt Lake stadium. He urgently needed Rs 1 Lakh for the operation and in return, he will give him his dollars.As per the deal, Halim reached Paribesh Bhavan the next day in the morning. Around 8:50 am, Kabil’s brother Musha and his father came with a packet wrapped in a towel. After the money and packet was exchanged, Musha asked Halim to verify the dollars.While Halim was unpacking it, both Musha and his father fled. On opening the packet, he found some folded newspapers and a diswashing soap bar.last_img read more

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Stranded tourists airlifted after rain halts in North Sikkim

first_imgDarjeeling: With the rains receding, evacuation of tourists was carried out by the Indian Army and Air Force in North Sikkim. National Highways 10, 31 and 31 C were restored, connecting Sikkim, Kalimpong and parts of Dooars with Siliguri.Connectivity of Sikkim and parts of Jalpaiguri remained cut off from Siliguri, owing to multiple landslides on National Highway 10, 31 and 31 C since Friday night, triggered by incessant rainfall. At many places the roads were washed away, while in others debris and rocks blocked the roads. Also Read – Rain batters Kolkata, cripples normal lifeThe worst affected was North Sikkim, with road connectivity between Mangan to Chungthang being totally damaged. Bridges were also washed away. The road from Gangtok to Mangan was also affected, resulting in tourists being stranded in Lachung, Chatten and Chungthang in North Sikkim.On Sunday, Trishakti Corps of the Indian Army and Indian Air Force, in coordination with civil administration, commenced air evacuation of tourists stranded in North Sikkim. On request of aid by the civil administration, helicopters of Army Aviation and Air Force were pressed into service. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThe helicopters flew several sorties to Gangtok and Sevok. Around 100 persons including senior citizens, children, tourists and the sick were evacuated. Medical aid was also provided to people requiring medical assistance before they were airlifted.”The Indian Army has also made necessary arrangements for tents, blankets and food for the stranded tourists,” stated an Army release.”With rains receding on Sunday, evacuation operations were possible. Work is on to open up the roads. Heavy machinery including earth movers have been pressed into service. It will take around 14 days to repair the road from Mangan to Chungthang and around 3 days to restore road connectivity from Mangan to Gangtok. GREF is working on a war footing,” stated Karma Bonpo, District Collector, North District, Sikkim, while talking to Millennium Post. The situation in Mangan in North Sikkim has improved considerably, with water supply and electricity being restored. Some houses have been damaged. Families residing in 3 buildings in Mangan were evacuated. “However no loss of life has been reported,” added the DC.”We have been working on a war footing to open up the NH 10, 31 and 31 C in West Bengal. Earth moving and cutting machinery has been pressed into service,” stated Uttam Pradhan, Assistant Engineer, NH.It was a trying time for both locals and tourists on Saturday. While many waited on the roads, others tried to negotiate the slide near Sevok by crossing over on foot.last_img read more

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Block Health Centre at Mirik to get upgraded

first_imgDarjeeling: Block Health Centre at Mirik is all set to get upgraded to a Sub-Divisional Hospital. Incidentally, Mirik was upgraded to a full-fledged sub-division from a block in Darjeeling on March 30, 2017. Chief Minister Mamata Banerjee had recently stated that Mirik hospital wouldsoon be upgraded. The Health department has already given a go-ahead to the upgradation of the existing hospital to a Sub-Divisional hospital. “This is to ensure that people of the sub-division get proper medical assistance without having to go outside. A new building will be constructed in the vacant land behind the existing hospital,” stated Dr Pralay Acharya, CMOH, Darjeeling. Also Read – Rain batters Kolkata, cripples normal lifeThe existing three-storey building will be renovated and a new four-storey building will come up. Estimates are being prepared for civil and electrical works. After we get the sanctions we will float tenders for the construction,” stated the CMOH. Sanctions will also be required for human resource. “The existing building will house the Out Patient department and have diagnostic facilities. The new building will house the In Patient department including Male and female medical wards; Male and female surgical wards; Obstetric ward; Paediatric ward; SNSU and a 6-bed HDU. A blood bank is also on the anvil,” stated Doctor Acharya. Currently, Block Health Centre is 30-bed and consists of five doctors and 15 nursing staff. “With the upgrade, there will be 100 beds with 20 doctors. The nursing staff strength will also be increased” added the CMOH.last_img read more

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