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IISc: Trapping, moving nanoparticles with light
By Shubashree Desikan
September 28, 2019 19:47 IST
Plasmonic tweezers are limited by the fact that they are fixed in space and can therefore only trap objects that come close to them.
Researchers at the Centre for Nano Science and Engineering at the Indian Institute of Science (IISc), Bengaluru, have developed a technique to trap and move tiny objects in the nanoscale using optical “tweezers” employing light. This is a tool that can be used to pick and move small suspended particles even including cells. This research has been published in Nature Communications.
Optical tweezers have been known for about thirty years now and are used in biology to hold and manipulate particles; however, they have a limitation when it comes to nanosized particles. This was partly solved with the development of “plasmonic tweezer” which works on the principle that when a disc of noble metal, like gold, is illuminated with light, it creates an electromagnetic field around the disc. This field can attract and hold on to tiny particles.
Plasmonic tweezers are limited by the fact that they are fixed in space and can therefore only trap objects that come close to them. Though the team, in an earlier work, showed that such plasmonic tweezers could be manoeuvred with a combination of light and magnetic fields, they could not apply the technique to some types of colloids.
Tweezer-in-a-tweezer
In the present work, they overcome this limitation by developing a method that uses only optical force. They integrate a silver nanodisc with a microrod made of glass and the combination can be manipulated using laser beams alone. This “tweezer-in-a-tweezer” approach can trap objects of about 40 nanometres in size, using a single laser beam. This is the typical size of a virus or DNA. “The optical tweezer holds the plasmonic tweezer and the plasmonic tweezers trap our target nanoparticles, therefore tweezer (plasmonic) in tweezer (optical),” says Souvik Ghosh, first author of the paper.
As the size of any colloidal particle decreases, for instance from micro-scale to nano-scale, the movement due to Brownian motion or random fluctuation increases. “Therefore, holding a single silver nanodisc with a focused laser beam (the optical tweezer) is challenging and needs high laser intensity to generate enough force to overcome the fluctuations,” explains Ghosh. If, in order to reduce the required laser intensity, the size of the disc were reduced, the plasmonic properties would be lost. Therefore, the team attached a dielectric microrod made of glass which while preserving the plasmonic property, reduces the thermal fluctuations by an order of magnitude. “The intensity required is about 100 times lower that what a regular optical tweezer typically uses to hold an object of similar dimensions,” he explains.
“The technique is ready for real world applications,” says Prof. Ambarish Ghosh, in whose lab the research was carried out. “Simplicity and ease of implementation are the biggest USPs for this device. It is patented and we are already in discussion with a company for licensing.”
IISc: Trapping, moving nanoparticles with light
By Shubashree Desikan
September 28, 2019 19:47 IST
Plasmonic tweezers are limited by the fact that they are fixed in space and can therefore only trap objects that come close to them.
Researchers at the Centre for Nano Science and Engineering at the Indian Institute of Science (IISc), Bengaluru, have developed a technique to trap and move tiny objects in the nanoscale using optical “tweezers” employing light. This is a tool that can be used to pick and move small suspended particles even including cells. This research has been published in Nature Communications.
Optical tweezers have been known for about thirty years now and are used in biology to hold and manipulate particles; however, they have a limitation when it comes to nanosized particles. This was partly solved with the development of “plasmonic tweezer” which works on the principle that when a disc of noble metal, like gold, is illuminated with light, it creates an electromagnetic field around the disc. This field can attract and hold on to tiny particles.
Plasmonic tweezers are limited by the fact that they are fixed in space and can therefore only trap objects that come close to them. Though the team, in an earlier work, showed that such plasmonic tweezers could be manoeuvred with a combination of light and magnetic fields, they could not apply the technique to some types of colloids.
Tweezer-in-a-tweezer
In the present work, they overcome this limitation by developing a method that uses only optical force. They integrate a silver nanodisc with a microrod made of glass and the combination can be manipulated using laser beams alone. This “tweezer-in-a-tweezer” approach can trap objects of about 40 nanometres in size, using a single laser beam. This is the typical size of a virus or DNA. “The optical tweezer holds the plasmonic tweezer and the plasmonic tweezers trap our target nanoparticles, therefore tweezer (plasmonic) in tweezer (optical),” says Souvik Ghosh, first author of the paper.
As the size of any colloidal particle decreases, for instance from micro-scale to nano-scale, the movement due to Brownian motion or random fluctuation increases. “Therefore, holding a single silver nanodisc with a focused laser beam (the optical tweezer) is challenging and needs high laser intensity to generate enough force to overcome the fluctuations,” explains Ghosh. If, in order to reduce the required laser intensity, the size of the disc were reduced, the plasmonic properties would be lost. Therefore, the team attached a dielectric microrod made of glass which while preserving the plasmonic property, reduces the thermal fluctuations by an order of magnitude. “The intensity required is about 100 times lower that what a regular optical tweezer typically uses to hold an object of similar dimensions,” he explains.
“The technique is ready for real world applications,” says Prof. Ambarish Ghosh, in whose lab the research was carried out. “Simplicity and ease of implementation are the biggest USPs for this device. It is patented and we are already in discussion with a company for licensing.”
IISc: Trapping, moving nanoparticles with light
Every Indian is classified as Caucasian. There are only three markers for the race-African, Caucasian and Mongoloid.
A revolutionary “Cold Chain Breaking Technology” in vaccines has been developed at IIT Kanpur IPA No 201911026648, involving a cost-effective method of increasing stability and storage time of a protein antigen against shigellosis, at variety of temperature conditions.
A Highly-stable Therapeutic Protein Antigen having Vaccine Application against Shigellosis, and a Simple and Cost-effective Method for Preparing the same – SIIC IIT Kanpur
A Highly-stable Therapeutic Protein Antigen having Vaccine Application against Shigellosis, and a Simple and Cost-effective Method for Preparing the same – SIIC IIT Kanpur
Scientists undertake largest DNA barcoding of spiders in India
DNA barcoding is a method for the quick identification of any species based on extracting a DNA sequence from a tiny tissue sample of any organism. In simple terms, it is the molecular signature of a species based on its genes.
Updated : Oct 11, 2019 11:42 IST
By Joydeep Thakur
Hindustan Times, Kolkata.
Scientists from the Zoological Survey of India (ZSI) have managed to barcode at least 100 species of spiders based on their DNA, in the largest exercise of its kind in the country.(Harvey Payne)
Scientists from the Zoological Survey of India (ZSI) have managed to barcode at least 100 species of spiders based on their DNA, in the largest exercise of its kind in the country.
The study includes species such as the spitting spiders (Scytodes thoracica), spiders with ‘natural’ mirrors in their abdomen (Thwaitesia sp) and those that steal others’ food (Argyrodes flavescens) – a phenomenon which scientists term as kleptoparasitism. Then there are species which are found only in India.
“This is the largest attempt on DNA barcoding of spiders from India. At least 101 species, with at least five endemic species, have been DNA barcoded. Work on DNA barcoding of at least 100 other Indian spiders is in progress,” the director of ZSI and a co-author of the research paper, Kailash Chandra, said.
The findings of the ongoing exercise have been published in Nature Publishing Group (NPG) journal, Scientific Reports – one of the leading multidisciplinary science journals in the world – in its October 1 issue.
Experts said that while most of the spiders are not dangerous, a few species can produce fatal skin allergies to humans. Many of these spiders are believed to be beneficial for us as they keep the population of several insects like mosquitoes under control.
DNA barcoding is a method for the quick identification of any species based on extracting a DNA sequence from a tiny tissue sample of any organism. In simple terms, it is the molecular signature of a species based on its genes.
“These are just like barcodes we find on products in shopping malls, which, when scanned, help us to know about the product, its price, expiry date and date of manufacture,” said Vikas Kumar, a ZSI scientist associated with the exercise.
“The DNA barcoding of spiders would help in easy identification of these creatures and help to know more about these animals and their evolution,” Kumar said.
Other authors of the publication are Kaomud Tyagi, Shantanu Kundu, John Caleb, Avas Pakrashi, and Priya Prasad.
“All the ‘voucher’ specimens of these barcoded species are available in the National Zoological Collections at ZSI in Kolkata for future research work,” said Kaomud Tyagi, another scientist in the team.
Dhruv Prajapati, an Ahmedabad-based arachnologist, said it was “indeed a significant research paper. “The availability of this data in public domain Barcode of Life Data System (BOLD) will help the researchers from across the world for future research,” Prajapati said.
Scientists had earlier published barcodes of around 17 species of spiders from the Western Ghats.
In May this year, Pakistani scientists had barcoded around 200 spider species.
“Both are pioneering works in the region. As many spider species are common for both India and Pakistan, these research works could provide a common platform for the scientists of the two neighbouring countries once they are uploaded on BOLD. They can be accessed by scientists across the world,” Sanjay Kesari Das, a Delhi based arachnologist who recently discovered a new species of a trap-door spider, said.
ZSI scientists said that there are around 1800 species of spiders in India, which is just around 4% of the arachnids found across the world.
Scientists undertake largest DNA barcoding of spiders in India
DNA barcoding is a method for the quick identification of any species based on extracting a DNA sequence from a tiny tissue sample of any organism. In simple terms, it is the molecular signature of a species based on its genes.
Updated : Oct 11, 2019 11:42 IST
By Joydeep Thakur
Hindustan Times, Kolkata.
Scientists from the Zoological Survey of India (ZSI) have managed to barcode at least 100 species of spiders based on their DNA, in the largest exercise of its kind in the country.
The study includes species such as the spitting spiders (Scytodes thoracica), spiders with ‘natural’ mirrors in their abdomen (Thwaitesia sp) and those that steal others’ food (Argyrodes flavescens) – a phenomenon which scientists term as kleptoparasitism. Then there are species which are found only in India.
“This is the largest attempt on DNA barcoding of spiders from India. At least 101 species, with at least five endemic species, have been DNA barcoded. Work on DNA barcoding of at least 100 other Indian spiders is in progress,” the director of ZSI and a co-author of the research paper, Kailash Chandra, said.
The findings of the ongoing exercise have been published in Nature Publishing Group (NPG) journal, Scientific Reports – one of the leading multidisciplinary science journals in the world – in its October 1 issue.
Experts said that while most of the spiders are not dangerous, a few species can produce fatal skin allergies to humans. Many of these spiders are believed to be beneficial for us as they keep the population of several insects like mosquitoes under control.
DNA barcoding is a method for the quick identification of any species based on extracting a DNA sequence from a tiny tissue sample of any organism. In simple terms, it is the molecular signature of a species based on its genes.
“These are just like barcodes we find on products in shopping malls, which, when scanned, help us to know about the product, its price, expiry date and date of manufacture,” said Vikas Kumar, a ZSI scientist associated with the exercise.
“The DNA barcoding of spiders would help in easy identification of these creatures and help to know more about these animals and their evolution,” Kumar said.
Other authors of the publication are Kaomud Tyagi, Shantanu Kundu, John Caleb, Avas Pakrashi, and Priya Prasad.
“All the ‘voucher’ specimens of these barcoded species are available in the National Zoological Collections at ZSI in Kolkata for future research work,” said Kaomud Tyagi, another scientist in the team.
Dhruv Prajapati, an Ahmedabad-based arachnologist, said it was “indeed a significant research paper. “The availability of this data in public domain Barcode of Life Data System (BOLD) will help the researchers from across the world for future research,” Prajapati said.
Scientists had earlier published barcodes of around 17 species of spiders from the Western Ghats.
In May this year, Pakistani scientists had barcoded around 200 spider species.
“Both are pioneering works in the region. As many spider species are common for both India and Pakistan, these research works could provide a common platform for the scientists of the two neighbouring countries once they are uploaded on BOLD. They can be accessed by scientists across the world,” Sanjay Kesari Das, a Delhi based arachnologist who recently discovered a new species of a trap-door spider, said.
ZSI scientists said that there are around 1800 species of spiders in India, which is just around 4% of the arachnids found across the world.
Scientists undertake largest DNA barcoding of spiders in India
This could be big news :
USFDA designates Indian invention a ‘breakthrough device’ for cancer | India News - Times of India
USFDA designates Indian invention a ‘breakthrough device’ for cancer | India News - Times of India
Uttar Pradesh Boy Develops 'Transparent Concrete' For Buildings
IANS, 16 August 2019.
The newly developed transparent concrete is free from carbon dioxide and is 15 per cent lighter.
A boy in Uttar Pradesh has developed 'transparent concrete' with steel, iron and plastic fibre scraps which will allow the sun rays to filter in.
The invention was made by Ramansh Bajpai, a student of the M.Tech course in Civil Engineering at the Harcourt Butler Technical University (HBTU) in Kanpur.
Walls made with this concrete will allow 30 per cent of sun rays through it and light up rooms.
The walls, however, will allow only sunlight and not the heat and this will lead to a 30 per cent reduction in electricity consumption.
Bajpai said that the walls made with this concrete will allow sunrays but will not allow air and water which means that buildings made with this material will not have the risk of dampness or leaking.
Dipesh Kumar Singh, under whose guidance Bajpai developed the concrete, said: "This concrete is 23 per cent stronger than the ordinary concrete. It costs only 33 per cent of the ordinary concrete and can be used with Plaster of Paris."
For instance, a wall made of transparent concrete will cost Rs 1,924 while one with the same measurement, made by bricks and concrete will cost Rs 5,800.
"We have used 40 per cent ground granulated blast furnace slag, commonly known as GGBS. This is obtained by quenching molten iron slag (a by-product of iron and steel-making) from a blast furnace in water or steam, to produce a glassy, granular product that is then dried and ground into a fine powder," Singh added.
GGBS has been widely used in Europe, and increasingly in the US and in Asia, particularly in Japan and Singapore, for its superiority in concrete durability, extending the lifespan of buildings from 50 years to a hundred years.
The newly developed transparent concrete is free from carbon dioxide and is 15 per cent lighter.
Uttar Pradesh Boy Develops 'Transparent Concrete' For Buildings
IANS, 16 August 2019.
The newly developed transparent concrete is free from carbon dioxide and is 15 per cent lighter.
A boy in Uttar Pradesh has developed 'transparent concrete' with steel, iron and plastic fibre scraps which will allow the sun rays to filter in.
The invention was made by Ramansh Bajpai, a student of the M.Tech course in Civil Engineering at the Harcourt Butler Technical University (HBTU) in Kanpur.
Walls made with this concrete will allow 30 per cent of sun rays through it and light up rooms.
The walls, however, will allow only sunlight and not the heat and this will lead to a 30 per cent reduction in electricity consumption.
Bajpai said that the walls made with this concrete will allow sunrays but will not allow air and water which means that buildings made with this material will not have the risk of dampness or leaking.
Dipesh Kumar Singh, under whose guidance Bajpai developed the concrete, said: "This concrete is 23 per cent stronger than the ordinary concrete. It costs only 33 per cent of the ordinary concrete and can be used with Plaster of Paris."
For instance, a wall made of transparent concrete will cost Rs 1,924 while one with the same measurement, made by bricks and concrete will cost Rs 5,800.
"We have used 40 per cent ground granulated blast furnace slag, commonly known as GGBS. This is obtained by quenching molten iron slag (a by-product of iron and steel-making) from a blast furnace in water or steam, to produce a glassy, granular product that is then dried and ground into a fine powder," Singh added.
GGBS has been widely used in Europe, and increasingly in the US and in Asia, particularly in Japan and Singapore, for its superiority in concrete durability, extending the lifespan of buildings from 50 years to a hundred years.
The newly developed transparent concrete is free from carbon dioxide and is 15 per cent lighter.
Uttar Pradesh Boy Develops 'Transparent Concrete' For Buildings
Study opens new avenue for preventing cancer
Scientists have found a way to stop the degradation of a protein called p53 that prevents cancer cells from proliferating and forming tumors
By Sunderarajan Padmanabhan
Last Updated: Wednesday 25 September 2019
In a new development in the area of cancer research, scientists at Delhi-based National Institute of Immunology (NII) have found a way to stop the degradation of a protein called p53 that prevents cancer cells from proliferating and forming tumors in the body.
p53 is one of the most well studied proteins in cancer biology. Like all proteins, its levels and activity are tightly controlled and they go through cycles of birth-existence-death: the protein is synthesised, it does its function and then it is degraded. When required, the protein is re-synthesised and the cycle keeps repeating.
Scientists across the world have been trying to find out how the level of p53 is regulated and what are the mechanisms underlying its degradation. The team of scientists at NII have now have shown that a protein called FBW7 is responsible for degrading p53. It degrades not only the wild type p53 but also mutant p53 version, which is involved in tumor promotion. As a validation of their finding, researchers haves hown that the half-life of p53 is increased and its function as tumor suppressor got enhanced in cancer cells that lacked FBW7.
The team has also worked out the mechanistic details of how FBW7α recognizes p53 and degrades it. Further, they have showed that the degradation happens as a result of damage to DNA induced by radiation and chemotherapy. Interestingly, FBW7 expression itself is dependent on p53 and it gets induced when cancer cells are exposed to DNA-damaging events. This indicates the presence of auto-regulatory loop in cells which tightly regulates the amount of p53 required to be present in the cells at any particular time.
“The results from our research provide novel ways of improving tumor regression by improving the function of p53 by stabilising its levels. This could be achieved by using a mutant of p53, which will not be degraded by FBW7α and may accentuate the therapeutic potential. Future work is needed to build on this startegy to find clinical application,” explained Sagar Sengupta, leader of the research team, while speaking to India Science Wire.
The study results have been published in the Journal of Biological Chemistry. The team included Vivek Tripathi, Ekjot Kaur, Suhas Sampat Kharat, Mansoor Hussain, Arun Prasath Damodaran and Swati Kulshrestha. The work was supported the Department of Biotechnology, Council of Scientific and Industrial Research, Science and Engineering Research Board and Department of Science and Technology. (India Science Wire)
Study opens new avenue for preventing cancer
Scientists have found a way to stop the degradation of a protein called p53 that prevents cancer cells from proliferating and forming tumors
By Sunderarajan Padmanabhan
Last Updated: Wednesday 25 September 2019
In a new development in the area of cancer research, scientists at Delhi-based National Institute of Immunology (NII) have found a way to stop the degradation of a protein called p53 that prevents cancer cells from proliferating and forming tumors in the body.
p53 is one of the most well studied proteins in cancer biology. Like all proteins, its levels and activity are tightly controlled and they go through cycles of birth-existence-death: the protein is synthesised, it does its function and then it is degraded. When required, the protein is re-synthesised and the cycle keeps repeating.
Scientists across the world have been trying to find out how the level of p53 is regulated and what are the mechanisms underlying its degradation. The team of scientists at NII have now have shown that a protein called FBW7 is responsible for degrading p53. It degrades not only the wild type p53 but also mutant p53 version, which is involved in tumor promotion. As a validation of their finding, researchers haves hown that the half-life of p53 is increased and its function as tumor suppressor got enhanced in cancer cells that lacked FBW7.
The team has also worked out the mechanistic details of how FBW7α recognizes p53 and degrades it. Further, they have showed that the degradation happens as a result of damage to DNA induced by radiation and chemotherapy. Interestingly, FBW7 expression itself is dependent on p53 and it gets induced when cancer cells are exposed to DNA-damaging events. This indicates the presence of auto-regulatory loop in cells which tightly regulates the amount of p53 required to be present in the cells at any particular time.
“The results from our research provide novel ways of improving tumor regression by improving the function of p53 by stabilising its levels. This could be achieved by using a mutant of p53, which will not be degraded by FBW7α and may accentuate the therapeutic potential. Future work is needed to build on this startegy to find clinical application,” explained Sagar Sengupta, leader of the research team, while speaking to India Science Wire.
The study results have been published in the Journal of Biological Chemistry. The team included Vivek Tripathi, Ekjot Kaur, Suhas Sampat Kharat, Mansoor Hussain, Arun Prasath Damodaran and Swati Kulshrestha. The work was supported the Department of Biotechnology, Council of Scientific and Industrial Research, Science and Engineering Research Board and Department of Science and Technology. (India Science Wire)
Study opens new avenue for preventing cancer
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Scientists concoct new coating to protect gun barrels from wear
By Ananya & V S Maheswaran
Bengaluru, Nov 12, 2019, (Research Matters)
Every time a bullet is fired, it scrapes away a bit of the material from inside the gun’s barrel. Over time, the size of the barrel increases. Not only does this call for frequent maintenance, but could also lead to mistakes in hitting the target. The inside of the barrel is coated with protective materials such as chromium to avoid wear and erosion. Chromium (VI)—the hexavalent form of chromium—is popularly used as an electrolyte for coating deposition since it’s readily available and easy to use. But, it is carcinogenic and is also susceptible to cracking and falling off.
The trivalent form of chromium—chromium (III)—is as an environment-friendly and safer alternative. In a recent study, researchers from the Indian Institute of Technology Kanpur have explored the use of a new blend of chromium (III) as an eco-friendly electrolyte for depositing chromium-based coatings on metallic barrels. They reinforced chromium with carbon nanotubes (CNTs) and a ceramic compound called yttria stabilised zirconia (YSZ), to improve the properties of the coat. The Council of Scientific and Industrial Research, MHRD and Swarnajayanti Fellowship funded the study.
Usually, the barrels are coated using the electro-deposition process in which the barrel is submerged in an electrolyte solution containing the dissolved coating material. When an electric current is applied to the barrel, the dissolved particles are activated, and they uniformly deposit on its surface.
“Due to the complicated chemistry involved in the process, it is difficult to obtain very thick coatings of trivalent chromium compared to hexavalent chromium plating,” says Dr Kantesh Balani, who led the current study. “Incorporating carbon nanotubes make it more resistant to wear, and YSZ reinforcement gives it strength, so we obtain better coatings even at low thickness,” adds Pragya Shukla, who participated in the study.
The researchers analysed the properties of four different combinations of coatings on a flat steel plate—only chromium, chromium with CNTs, chromium with YSZ, and chromium with both CNT and YSZ.
Since YSZ is a non-conductor, the conductivity of the coating solution decreases, resulting in a thin layer of chromium and YSZ. In contrast, carbon nanotubes are conductors and increase the conductivity of the solution, forming a thicker layer of chromium and carbon nanotubes about twice the thickness of the chromium and YSZ coating.
Specific mechanical properties of the coating improved due to the additives. The researchers observed an increase in hardness of the coating and its resistance to wear. The chrome layer with both carbon nanotubes and YSZ was the hardest and most resistant to wear, indicating that it is least likely to erode. Moreover, when they scratched the surface with a steel ball, they found that there was less wear in the coatings containing carbon nanotubes than in the ones that did not. They attribute this to the lubrication provided by the carbon nanotubes.
The lowest wear in the coating with both carbon nanotubes and YSZ, report the researchers, highlighting the combined effect of the two additives. The zirconia strengthens the coat and reduces the propagation of cracks while carbon nanotubes lubricate and also fill up any cracks that might develop.
Using this new mixture instead of chromium (VI) would only need replacing the coating solution currently used in the industry. The suggested change is compliant with the current processes and would not require significant investments for its implementation.
“There will be a minor increase in cost due to the use of carbon nanotubes and YSZ. But, it would incur much lower costs than for other plating processes both in terms of investment and operating costs including labour costs,” says Shikha, a co-author of this study. “Besides, an enhanced life of the gun barrels may mandate the use of these coatings for ensuring the safety and longevity of barrels.” adds Dr. J. Ramkumar, another member of the team that carried out the study.
In the future, the researchers plan to test this coating on curved surfaces and with varying concentrations of carbon nanotubes and YSZ.
The researchers envision this plating process to be useful for not just gun barrels, but also hydraulic cylinders and rods, pistons for internal combustion engines and cutting tools.
“It can also be used in rebuilding worn parts such as rolls, moulding dies, cylinder liners and crankshafts,” signs off Dr Balani.
This article has been run past the researchers, whose work is covered, to ensure accuracy.
Scientists concoct new coating to protect gun barrels from wear
Scientists concoct new coating to protect gun barrels from wear
By Ananya & V S Maheswaran
Bengaluru, Nov 12, 2019, (Research Matters)
Every time a bullet is fired, it scrapes away a bit of the material from inside the gun’s barrel. Over time, the size of the barrel increases. Not only does this call for frequent maintenance, but could also lead to mistakes in hitting the target. The inside of the barrel is coated with protective materials such as chromium to avoid wear and erosion. Chromium (VI)—the hexavalent form of chromium—is popularly used as an electrolyte for coating deposition since it’s readily available and easy to use. But, it is carcinogenic and is also susceptible to cracking and falling off.
The trivalent form of chromium—chromium (III)—is as an environment-friendly and safer alternative. In a recent study, researchers from the Indian Institute of Technology Kanpur have explored the use of a new blend of chromium (III) as an eco-friendly electrolyte for depositing chromium-based coatings on metallic barrels. They reinforced chromium with carbon nanotubes (CNTs) and a ceramic compound called yttria stabilised zirconia (YSZ), to improve the properties of the coat. The Council of Scientific and Industrial Research, MHRD and Swarnajayanti Fellowship funded the study.
Usually, the barrels are coated using the electro-deposition process in which the barrel is submerged in an electrolyte solution containing the dissolved coating material. When an electric current is applied to the barrel, the dissolved particles are activated, and they uniformly deposit on its surface.
“Due to the complicated chemistry involved in the process, it is difficult to obtain very thick coatings of trivalent chromium compared to hexavalent chromium plating,” says Dr Kantesh Balani, who led the current study. “Incorporating carbon nanotubes make it more resistant to wear, and YSZ reinforcement gives it strength, so we obtain better coatings even at low thickness,” adds Pragya Shukla, who participated in the study.
The researchers analysed the properties of four different combinations of coatings on a flat steel plate—only chromium, chromium with CNTs, chromium with YSZ, and chromium with both CNT and YSZ.
Since YSZ is a non-conductor, the conductivity of the coating solution decreases, resulting in a thin layer of chromium and YSZ. In contrast, carbon nanotubes are conductors and increase the conductivity of the solution, forming a thicker layer of chromium and carbon nanotubes about twice the thickness of the chromium and YSZ coating.
Specific mechanical properties of the coating improved due to the additives. The researchers observed an increase in hardness of the coating and its resistance to wear. The chrome layer with both carbon nanotubes and YSZ was the hardest and most resistant to wear, indicating that it is least likely to erode. Moreover, when they scratched the surface with a steel ball, they found that there was less wear in the coatings containing carbon nanotubes than in the ones that did not. They attribute this to the lubrication provided by the carbon nanotubes.
The lowest wear in the coating with both carbon nanotubes and YSZ, report the researchers, highlighting the combined effect of the two additives. The zirconia strengthens the coat and reduces the propagation of cracks while carbon nanotubes lubricate and also fill up any cracks that might develop.
Using this new mixture instead of chromium (VI) would only need replacing the coating solution currently used in the industry. The suggested change is compliant with the current processes and would not require significant investments for its implementation.
“There will be a minor increase in cost due to the use of carbon nanotubes and YSZ. But, it would incur much lower costs than for other plating processes both in terms of investment and operating costs including labour costs,” says Shikha, a co-author of this study. “Besides, an enhanced life of the gun barrels may mandate the use of these coatings for ensuring the safety and longevity of barrels.” adds Dr. J. Ramkumar, another member of the team that carried out the study.
In the future, the researchers plan to test this coating on curved surfaces and with varying concentrations of carbon nanotubes and YSZ.
The researchers envision this plating process to be useful for not just gun barrels, but also hydraulic cylinders and rods, pistons for internal combustion engines and cutting tools.
“It can also be used in rebuilding worn parts such as rolls, moulding dies, cylinder liners and crankshafts,” signs off Dr Balani.
This article has been run past the researchers, whose work is covered, to ensure accuracy.
Scientists concoct new coating to protect gun barrels from wear