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Mumbai Monday, 19 November, 2018 - 07:07

Researchers from IIT Bombay are working on methods to ease the machining of titanium through annealing

Titanium alloys, made from the lustrous metal titanium, are used in a wide range of products—from aircraft engines to mechanical implants inside the human body. Their widespread use is due to their unique property of being durable, hard, lightweight, resistant to corrosion and biocompatible—they are non-toxic to our body. However, these properties have a flip side; they make titanium alloys a stubborn material to cut into the desired shape. Could changing the physical properties of these alloys make it easier to cut them?

That’s the question keeping a group of researchers, led by Prof. Sushil Mishra of the Department of Mechanical Engineering, at the National Centre for Aerospace Innovation and Research, Indian Institute of Technology Bombay, busy. In the past three years, the researchers have devised and implemented various methods, like annealing that involves heating and gradual cooling, and laser heating, to change the structure of the alloys at a molecular level. These easy to implement methods are aimed at making the alloys easier to machine—the process of cutting them into the desired shape by removing excess material.

Turning is a popular machining method used for making components. A tool is used to scrape off material from the surface of a rotating cylindrical bar until the desired shape is obtained. In the case of titanium, turning is not easy since the hardness of the metal results in an uneven movement of the cutting tool. This shortcoming poses a significant disadvantage for the fabrication of parts used in biomedical applications, where a smooth surface finish is important. During turning, the material gets deformed just below the surface (subsurface deformation) when the tool scrapes off material from the surface, weakening the structural properties of the final component and making it susceptible to corrosion.  Also, the heat generated due to friction while cutting is not quickly dissipated as titanium is a bad conductor of heat, leaving the surface rough and uneven.

The excessive heat also damages the cutting tool and blunts its edges, increasing its maintenance cost. While there are changes made to the tool material, its geometry and machining parameters, and coolant used to facilitate heat dissipation, to overcome these drawbacks, these methods add to the cost, sometimes making it as expensive as procuring the titanium alloy!

Research in the past has shown that the machinability of titanium alloys is determined by various factors, including their hardness, size and texture of crystals, and their composition. Hence, changing the microstructure of the titanium alloy could help in enhancing its machinability. The researchers at the National Centre for Aerospace Innovation and Research, IIT Bombay, are pondering on the possibility of changing these factors, using annealing and laser heating.

New approaches to improve machinability

One way to change the crystal structure of titanium alloy is to heat it to the ‘recrystallisation temperature’—a temperature that is sufficiently high but lower than the melting temperature--- and then gradually cool or anneal it. The researchers at IIT Bombay tested annealing at two temperatures—at about 700°C and 900°C. They found that when the alloy was heated to about 700°C, it recrystallised partially, and when heated to about 900°C, it recrystallised fully, forming a larger grain structure. The hardness of the annealed samples decreased with an increase in the annealing temperature.

“The samples directly received from the vendors are approximately 18% harder than the samples annealed at 925°C”, say the researchers involved in this effort.

They also observed that recrystallisation reduces the reactive force that the tool experiences while cutting, and the subsurface deformation resulting from it. While annealing achieved easy machinability, it still was not the best option to retain some of the desirable properties of the titanium alloys, like their strength. The researchers then looked at laser heating to address this.

It is often enough to have a low hardness of materials only at its surface where it gets cut during machining. Hence, the researchers attempted to change the microstructure of the alloy only on the surface by selective heating using a laser beam. They moved a focussed laser beam from one end of the alloy sample to the other end to heat the surface to temperatures as high as 1200°C, well beyond its recrystallisation temperature. They controlled the intensity of the laser beam to prevent the sample from melting and cooled it down gradually. After this process, they observed that needle-shaped crystals were formed near the surface and subsurface. The regions further away from the surface had crystals wider in shape, similar to the original material.

The researchers experimented by moving the laser across the samples at different speeds of 10, 15, 20 and 25 millimetre/minute and observed a significant change for scanning speeds up to 20 millimetres/minute, but no substantial difference beyond this speed.

“At higher scanning speeds, the time for heat penetration in the sample was less due to the low thermal conductivity of the alloy. Therefore, the depth of the laser affected region is minimal in this condition, and there is very little change in the microstructure,” explain the researchers.

Overall, the hardness at laser affected zone is higher than that of original material. The increase in hardness and changes in microstructure is helpful in decreasing the fluctuation on cutting tool associated with titanium machining. This leads to improvement in tool life. Further, after removal of material inside laser affected zone through machining, some layer of modified microstructure with higher hardness (higher than the original material) still remains. This fortifies it against subsequent damage and fracture.

The laser-treated samples were easy to cut, and the variation in the opposing force during cutting was lower, resulting in a better surface finish. For these samples, the researchers also studied the way in which the material was chipped off while cutting. The chips were longer than those cut from the original material, which indicates that the tool could cut the sample evenly without significant vibrations. These factors would prevent tool damage and lead to longer tool life. The researchers also developed a numerical model to simulate the process of laser annealing and found that the results matched with the experimental observations.

A significant challenge in using lasers was that the depth of heat penetration increased along the length of each sample as the heat accumulated in the alloy. “Initially, the depth of penetration increased significantly and then became almost constant at the end of scanning, about 25-30 millimetre from the starting point of laser heating,” say the researchers. This uneven heating may lead to material wastage since only the parts of the material with uniform heat penetration can be used for the final component. “Using the numerical model, this problem can be resolved by varying the laser power along the length to maintain uniform heat penetration depth for a particular sample”, suggest the researchers.

“Both annealing and laser treatment are routine operations used in the industries. The approaches suggested in this research do not need special accommodations and can be implemented immediately,” says Prof. Mishra, talking about the results of their hard work.

“We need to study the tool life with laser treated samples in comparison with the untreated samples. The treatment methodology can also be extended to other machining operations such as milling”, he concludes, talking about the future scope of research.


The article is based on the following works:

A new approach to control and optimize the laser surface heat treatment of materials

Microstructural Development Due to Laser Treatment and Its Effect on Machinability of Ti6Al4V Alloy

Effect of microstructure and cutting speed on machining behavior of Ti6Al4V alloy

Influence of Laser Heat Treatment on Machinability of Ti6Al4V Alloy

Section: General, Science, Technology, Deep-dive Source:
Delhi Friday, 16 November, 2018 - 14:36

Prof. Amit Kumar, Jaswinder and Tarvinder Chadha Chair Professor in the Department of Computer Science and Engineering at the Indian Institute of Technology Delhi, has been awarded the prestigious Shanti Swarup Bhatnagar Prize for Science and Technology 2018. He is recognised for his outstanding research in the field of Combinatorial Optimisation and Graph-Theoretic Algorithms under the Mathematical Sciences category.

The Shanti Swarup Bhatnagar Prize (SSB), awarded by the Council of Scientific and Industrial Research (CSIR), is the most prestigious recognition in Science and Technology in the country. It is named after the founder Director of CSIR, Shanti Swarup Bhatnagar and consists of Rs 5,00,000 prize money and a citation plaque. The Prize is awarded to researchers in the field of Biological Sciences, Chemical Sciences, Earth, Atmosphere, Ocean and Planetary Science, Engineering Sciences, Mathematical Sciences, Medical Sciences, and Physical Sciences.

Prof. Kumar said that the award would motivate him to work with even more enthusiasm in his research area.

“Looking forward, we want to motivate more undergraduate students to take up research as a career. Any research area needs a critical mass of researchers. This change is slowly happening in theoretical computer science in India”, he says.

Prof. Kumar’s research interest lies in the area of theoretical computer science, with emphasis on problems arising in scheduling, resource allocation, graph theory and clustering. “Many of these problems are fundamental in nature and have been studied for many years (or decades). Often one needs to design algorithms which use novel heuristics, and formally prove that they give good solutions”, he explains.

One such example is the scheduling of tasks in large data centres, which have immense computing resources and billions of jobs lined up. How does one schedule tasks such that the resources are used optimally? “Optimality could mean minimising the overall delay of tasks, or energy consumed by the processors, or some combination of the two”, explains Prof. Kumar.

Sometimes, these tasks may not be known in advance, and scheduling algorithms need to make decisions after considering other adversarial factors. These algorithms are called on-line algorithms. “My research focuses on resource allocation problems in graph theory where we want to connect a set of users or computers in a network optimally”, adds Prof. Kumar, talking about his work.

Also a recipient of the Indian National Academy of Engineer (INAE) Young Engineer Award, Indian National Science Academy (INSA) Young Scientist Award and the IBM Faculty Award. Prof. Kumar has broad industry and academic experience in India and abroad.

 

Section: General, Science, Technology, News Source:
मुंबई Thursday, 15 November, 2018 - 21:24

ओतकाम करणार्‍या लघु आणि मध्यम कारखान्यातील ग्रीन सॅंडचा पुनर्वापर करण्यासाठी अत्यंत प्रभावी पर्याय संशोधकांनी विकसित केला आहे.

नळांपासून ते वाहनातील गेयरबॉक्स पर्यन्त, आपल्या दैनंदिन वापरातील वस्तूंपैकी सुमारे ७०% वस्तू "सॅंड कास्टिंग" नावाच्या ओतकाम पद्धतीने कारखान्यात निर्माण केल्या जातात. यासाठी सुमारे ८०% वाळू आणि सुमारे १०% चिकणमाती ह्याचे मिश्रण करून तयार केलेल्या 'ग्रीन सॅंड' च्या साच्यात वितळलेले धातू ओतले जातात. यावेळेस तापमान १५०० डिग्री सेल्सियस पर्यंत वर जाते व या तापमानाला वाळूच्या कणांवर चिकणमातीचा एक थर निर्माण होतो. अशी वाळू परत ओतकामासाठी वापरता येत नाही. प्रदूषण करू शकणारी ही वाळू तशीच टाकून देणे योग्य नाही. योग्य पद्धतीने वाळूची विल्हेवाट लावायचा खर्च लघु ओतकाम कारखान्यांच्या दृष्टीने खूप असतो. यावर एक उपाय भारतीय तंत्रज्ञान संस्था, मुंबई येथील संशोधकांकडे अाहे. त्यांनी ग्रीन सॅंडचा पुनर्वापर करण्याची प्रभावी आणि वाजवी पद्धत प्रस्तावित केली आहे.

ग्रीन सॅंडचा पुनर्वापर करण्याच्या विद्यमान पद्धती एका तासात अनेक टन वाळूवर प्रक्रिया करू शकतात, पण या पद्धती अत्यंत महाग असतात. भारतातील ४६०० ओतकाम कारखान्यांपैकी सुमारे ८०% कारखाने लघु आणि मध्यम आकाराचे आहेत व त्यांना प्रतिदिन सुमारे फक्त १००० किलो वाळू वर प्रक्रिया करावी लागते, त्यामुळे त्यांना विद्यमान पुनर्वापर पद्धती परवडत नाहीत. ग्रीन सॅंड पाण्यात किंवा कचर्‍यात फेकून देणे हाच पर्याय त्यांच्याकडे उरतो. पण वापरलेल्या ग्रीन सॅंडमध्ये शिसे आणि टिन ह्यासारखे जड धातू असतात, जे जमिनीत व पाण्यात शोषले जाऊन प्रदूषण होते. म्हणून ग्रीन सॅंड फेकण्यावर कायद्याने निर्बंध आहेत. एकीकडे वापरलेल्या वाळूची विल्हेवाट कशी लावावी का प्रश्न असताना, दुसरीकडे अनेक राज्यात वाळू खणण्यावर बंदी आणल्यामुळे नवीन वाळू विकत घेणे पण खर्चिक असते. त्यामुळे ग्रीन सॅंडचा पुनर्वापर करणे हा आकर्षक पर्याय ठरतो.

ह्या अभ्यासाचे प्रमुख शास्त्रज्ञ, भारतीय तंत्रज्ञान संस्था मुंबई येथील प्राध्यापक संजय महाजनी आणि त्यांच्या सहकार्‍यांनी ग्रीन सॅंड पुन्हा वापरता येण्याजोगी करता येण्यासाठी खर्चिक अश्या उष्णता-प्रक्रिया पद्धती ऐवजी यांत्रिकी पद्धती प्रस्तावित केल्या आहेत. संशोधकांनी "अब्रेशन अँड सिव्हिंग युनिट" हे घर्षण आणि चाळणे ह्या संकल्पनांवर चालणारे यंत्र वापरुन वाळूच्या कणांवरील चिकणमाती काढण्यासाठी एक वाजवी आणि कार्यक्षम पद्धत विकसित केली आहे.

ग्रीन सॅंडचा पुनर्वापर करता येण्यासाठी त्यावरील चिकणमातीचा थर काढणे अनिवार्य असते. हा थर काढण्यासाठी संशोधकांनी तीन यांत्रिक पद्धतींची चाचणी केली. पहिल्या पद्धतीत एका उभ्या नळीत वाळू ठेवून त्यात ऊच्च दाबाने हवा सोडली, जेणेकरून वाळूचे कण एकमेकांवर घासले जावेत. दुसर्‍या पद्धतीत उभ्या नळीच्या ऐवजी आडवी नळी वापरली. असे केल्याने वाळूचे कण नळीच्या भिंतींवर पण आपटले गेले. तिसर्‍या पद्धतीत घर्षण वाढवण्यासाठी वाळूत छोट्या आकाराची वजने टाकून ती एका हलणार्‍या चाळणी वर ठेवली ज्यामुळे चिकणमाती वेगळी करणे सोपे झाले. त्यांनी तिन्ही पद्धतीसाठी लागणारा खर्च, आणि न निघालेल्या चिकणमातीचे प्रमाण मोजले.

संशोधकांना आढळून आले की घर्षण आणि चाळणे पद्धत सर्वोत्तम ठरली. प्राध्यापक महाजनी ह्यांनी दोन टप्प्यांची पद्धत सुचवली, ज्यात पहिल्या टप्प्यात वाळूचे कण 'अगेट'च्या छोट्या खड्यांवर घासले जातात आणि दुसर्‍या टप्प्यात चिकणमाती चाळली जाते. वाळूच्या कणांवरील चिकणमातीचा थर निघेल पण वाळूचे कण अजून बारीक होऊ नयेत अशा वजनाचे अगेटचे खडे त्यांनी निवडले. सुमारे ४० ग्राम वजनाचे खडे योग्य असतात असे संशोधकांना आढळले. दुसर्‍या टप्प्यात ५० मायक्रॉन (मानवी केसांच्या जाडीचे) आकाराची छिद्र असलेली जाळी लावलेले गोल फिरणारे पिंप वापरले. ह्या टप्प्यात वाळूचे कण एकमेकांवर घासले जातात ज्यामुळे कणांवरील चिकणमातीचा थर निघून जातो. वाळूच्या कणांपेक्षा चिकणमातीचे कण लहान असल्यामुळे ते चाळणीतून चाळले जातात आणि राहिलेली वाळू परत ओतकामासाठी वापरण्या योग्य होते.

काही वेळा ग्रीन सॅंडमध्ये आर्द्रतेचे प्रमाण अधिक असले तर घासले जाऊन सुद्धा चिकणमातीचा थर नीट निघत नाही. म्हणून प्रक्रिया करण्यापूर्वी वाळूतील आर्द्रता कमी करण्यासाठी एक हीटर आणि ब्लोअर प्रणाली वापरून वाळूवर गरम हवा फवारली जाते. पिंप फिरवण्याची गती, अगेट खड्यांचा आकार आणि वजन, वाळूतील आर्द्रता आणि तापमान ह्या सर्व घटकांचा परिणाम वरील प्रणाली वापरून वाळूवरील चिकणमाती किती प्रभावीपणे काढता येईल यावर होतो.

ही प्रस्तावित पद्धत खरंच किती कार्यक्षम आणि वाजवी आहे? संशोधकांनी गणित केले की दोन टप्प्याची प्रस्तावित पद्धत वापरल्यास खरच रु ५५० प्रति टन आला व २.२% चिकणमाती उरली. ह्याच्या तुलनेत उभ्या नळीच्या पद्धतीत व आडव्या नळीच्या पद्धतीत अनुक्रमे रु २७०० प्रति टन आणि रु ५६०० प्रति टन एवढा खर्च आला आणि ४.४% आणि २.२% एवढी चिकणमाती उरली. इतर दोन पद्धतींच्या तुलनेत प्रस्तावित दोन टप्प्यांची पद्धत बसवण्यासाठी खर्च अधिक येत असला तरीही नवीन प्रक्रिया वापरण्याची किंमत कमी आहे. नव्याने वाळू विकत घ्यायची झाल्यास ती सुमारे रु ३२०० प्रति टन किंमतीला मिळते. म्हणजेच, ही पद्धत वापरल्यास नवीन वाळू विकत घेण्याच्या तुलनेत सुमारे ८३% बचत होते.

संशोधकांनी प्रति तास १०० किलो ग्रीन सॅंडवर प्रक्रिया करणार्‍या यंत्राचा नमुना बनवला आहे. लोकांचा त्याला चांगला प्रतिसाद आहे. आतापर्यन्त मिळालेल्या यशाबद्दल बोलताना प्राध्यापक महाजनी म्हणाले, "शासकीय तंत्रनिकेतन महाविद्यालय, कोल्हापूर, महाराष्ट्र इथे आम्ही दोन टप्प्याचे यंत्र बसवले आहे. कोल्हापूर क्षेत्रात ओतकामाचे अनेक कारखाने आहेत. आम्ही अशा छोट्या कारखान्यातून वाळू एकत्र करून त्यावर प्रक्रिया करतो. आतापर्यन्त दिसलेले परिणाम समाधानकारक आहे. स्थानिक लोकांनी आमच्या कामाचे कौतुक केले आहे आणि प्रक्रिया केलेली वाळू वापरणे सुरू केले आहे."

'जर्नल ऑफ मटेरियल्स प्रॉसेसिंग टेक्नॉलॉजी' ह्यात प्रकाशित झालेला वरील अभ्यास लघु आणि मध्यम ओतकाम कारखान्याच्या मालकांसाठी अत्यंत उपयोगी आहे. ह्या शोधामुळे त्यांना पर्यावरण कायद्यांचे पालन करणे, आणि वाजवी किंमतीत वापरलेली वाळू परत वापरता येणे शक्य होईल. संशोधक आता ह्या पद्धतीत सुधारणा करण्याचा प्रयत्न करत आहेत.

प्राध्यापक महाजनी भविष्यातील योजनेबद्दल सांगताना म्हणतात, "उष्णता-प्रक्रिया आणि यांत्रिक पद्धती एकत्रित वापरणारे यंत्र विकसित करण्याचा प्रयत्न आम्ही करत आहोत. उष्णतेचा व्यय कमीत कमी व्हावा म्हणजे प्रक्रियेची किंमत कमी होईल असा प्रयत्न आम्ही  करत आहोत."

Section: General, Science, Technology, Deep-dive Source:
Kanpur Thursday, 15 November, 2018 - 19:19

Prof. Nitin Saxena, Professor at the Department of Computer Science and Engineering, Indian Institute of Technology Kanpur, has been awarded the 2018 Shanti Swarup Bhatnagar Prize for his work in Algebraic Complexity Theory. One of the youngest awardees, Prof. Saxena’s research interests include Computational Complexity and Algebraic Geometry.

The Shanti Swarup Bhatnagar Prize, named after the founder of the Council of Scientific and Industrial Research (CSIR), is awarded for outstanding and notable research in the field of science and engineering. It includes Rs 5,00,000 prize money, a citation plaque and a fellowship till the age of 65.

“The award, with a long history of 61 years, has witnessed great scientists and engineers. I feel very fortunate to have become part of this illustrious gathering. It inspires me to continue working on hard problems in my field and to mentor the next generation of complexity theorists,” says Prof. Saxena about this honour. He is thankful to his family for their love and support; and teachers and friends for the motivation. “I would like to dedicate all my wins to them,” he adds.

Prof. Saxena’s work deals with a topic in Mathematics called Polynomial Identity Testing and certain mathematical objects called ‘algebraic circuits’. Some mathematical problems, like solving a sudoku puzzle, could have fast and accurate approaches. However, a problem like finding all possible ways to solve a sudoku puzzle of any size becomes an extremely complex one. Such complex problems can be represented by polynomials—expressions that involve variables and operations like addition, subtraction, multiplication and exponents.

Polynomial Identity Testing explores if two polynomials, involving multiple variables, are equal. Algebraic methods help in determining how complicated it would be to solve this. Theoretical research in the area of Polynomial Identity Testing could potentially help in cryptography, error-correction, optimisation of algorithms and systems, and machine learning.

Algebraic circuits are used to compute polynomial equations and for Polynomial Identity Testing. A problem to be solved is represented as an algebraic circuit—a graph consisting of nodes and gates to represent inputs and operations, with directed connections between them. The number of nodes and edges represent the ‘size’ of the graph and is a representative of how long a computer could take to solve the problem.

Given a polynomial equation, one needs to find some circuit that can compute the polynomial, called upper bound problem, and also prove that a proposed circuit corresponds to the fastest way to solve it, known as the lower bound problem. “Often, this structural 'size' is more convenient to study than the sequential notion of 'time',” explains Prof. Saxena. A lower bound problem can be described as finding the smallest algebraic circuit corresponding to a polynomial. 

Simple polynomial equalities, like (X-Y) (X+Y) = X2 - Y2, can be established by solving algebraically. However, when the polynomials of interest contain many variables and higher powers, the complexity increases exponentially. Finding out the exact computational complexity of Polynomial Identity Testing is one of the most important unsolved problems in this subject area. Prof. Saxena took a step forward in solving this problem through establishing that studying a very special type of circuit models would be enough to understand the properties of general circuits.

In a related study, Prof. Saxena has also developed a new framework that helped to solve another unsolved problem. He and his collaborators found a solution for Polynomial Identity Testing for the model of an algebraic circuit that has very few input variables. Here, only the inputs and outputs of a circuit are known, and the exact internal connections are not known. The proposed technique to solve this problem is likely to be useful in addressing other unsolved problems in mathematics.

The study of algebraic circuits also gives rise to new mathematical concepts. For example, Prof. Saxena has proved that the roots or solutions of specific ‘small’ circuits will be ‘small circuits’. The result is not obvious, as some small size circuits can compute very large polynomials, and the solutions of those can be large. He has also developed a new algorithm to find out whether a system of polynomial equations has a root which is very closely approximate but not exact. The new algorithm is orders of magnitude better than previous algorithms regarding computing resources and implementation time.

Prof. Saxena wishes to focus on other open problems in the area of algebraic circuits. “I would like to continue working towards strengthening the techniques and increasing their scope,” he concludes.

Section: General, Science, Technology, News Source:
Bengaluru Thursday, 15 November, 2018 - 11:52

Research from IISc finds a vital link between immune system disorders and psychological conditions like OCD.

Our body and mind have a unique connection; perturbations in one has ramifications on the other. Many chronic physical health problems cause severe psychological stress, and vice-versa. Sometimes, our immune system can mistakenly attack our body, which it is meant to protect in the first place. Autoimmune disorders like rheumatoid arthritis affecting the joints, or multiple sclerosis affecting our nerve cells, are a result of such unintentional attack by our immune system. In a recent study, researchers at the Indian Institute of Science, Bengaluru, have shown how our immune system can also trigger mental health conditions like obsessive-compulsive disorder (OCD).

Obsessive-compulsive disorder is a condition marked by uncontrollable, reoccurring thoughts and behaviours with an urge to repeat again and again. Studies in the past have shown associations between disorders of the immune system, called autoimmune diseases, and mental health problems like depression and OCD. However, the precise role of the immune system in causing such conditions was not clear. In the current study, published in the journal Frontiers in Immunology, Prof. Avadhesha Surolia and his group at IISc have thrown some insights into how immune system disorders affect mental health. The study was funded by the Council of Scientific and Industrial Research (CSIR) and the Science and Engineering Research Board (SERB).

The researchers of the study artificially induced autoimmune encephalomyelitis—a condition where the immune system attacks the brain cells—in mice. They carefully observed the psychological impact of this condition and found that the mice started showing unexpectedly high levels of grooming activities. Their repetitive grooming behaviour was quite similar to symptoms exhibited by individuals affected with OCD.

The researchers further investigated which component of the immune system was responsible for triggering OCD-like behaviour in the mice. When they looked closely at the brains of the mice that showed OCD-like behaviour, they saw a marked increase in the levels of T helper 17 cells (Th17)—a type of cell in our immune system. Studies have shown that apart from Th17, another kind of cell, called Th1, also causes autoimmune responses. The researchers then experimentally transferred more of Th17 and Th1 cells into mice and found that Th17 was indeed the only one responsible for inducing OCD-like behaviour.

“This is the first study where we found Th17 cells to be intimately associated with OCD-like disease in mice”, shared Prof. Surolia in an interview with Research Matters. “However, OCD has been reported as a co-morbid condition in autoimmune diseases like inflammatory bowel disease, systemic lupus erythematosus and rheumatoid arthritis, where certain other components of the immune system (such as auto-antibodies or cytokines) may also be involved,” he added.

The study also found many other pieces of evidence that linked Th17 to inducing OCD. For instance, when the affected mice were treated with fluoxetine, an antidepressant that boosts the absorption of the neurotransmitter serotonin, they observed reduced OCD-like behaviour. Serotonin is a chemical produced by the nerve cells that regulates our mood. “The levels of serotonin are usually much lower in the brains of OCD patients. Hence, they respond positively to treatments with a chemical like this”, explained Prof. Surolia. The researchers also tried to eliminate Th17 cells using a drug called digoxin and observed that the mice significantly reduced their abnormal grooming behaviour.

The findings of the study could help design new approaches to treat conditions like OCD, hope the researchers.

“The present study, in my view, will change our perspective, where until now, we have looked at neuropsychiatric diseases as purely a neurological problem ignoring rather completely the immunologic contribution. Our findings will thus open up new avenues for treating OCD by developing effective therapeutic molecules that target Th17 cells. We can thus treat the root cause of the malady rather than targeting its manifestation and symptoms”, signs off Prof. Surolia.

Section: General, Science, Health, Society, Deep-dive Source:
मुंबई Thursday, 15 November, 2018 - 08:37

आईआईटी मुंबई का संशोधन बताता है की हवा में मौजूद प्रदूषक  कृषि के लिए उपलब्ध जल को प्रभावित करते है।

लगभग दो तिहाई भारतवासियों की रोज़ी रोटी कृषि पर निर्भर करती है। अधिकांश खेती वर्षा पर आधारित होने के कारण कितनी वर्षा कब होती है इसका प्रभाव उनपर पड़ता है।  बीसवीं शताब्दी के दूसरे अर्ध भाग में कम वर्षा के कारण अनाज उत्पाद कम हुआ है। क्या अनियमित वर्षा का सम्बन्ध प्रदूषण के बढ़ते स्तर से जुड़ा है? भारतीय प्रौद्योगिकी संस्थान मुंबई में किया अध्ययन यही  सूचित करता है। खोजकर्ता श्री.प्रशांत दवे, प्राध्यापक भूषण और प्राध्यापक चन्द्रा वेंकटरामन ने पाया कि एरोसोल्स बढ़ने के कारण वर्षा कम होती है जिससे सूखा पड़ता है और उसका परिणाम कृषि पर होता है।  

एरोसोल मतलब ठोस कण, तरल बूंदों, या ठोस-तरल कणों का ऐसा मिश्रण है जो हवा में निलंबित रहते हैं। धूल, समुद्री नमक, जैविक इंधन जलाने से उत्सर्जित होनेवाले सूक्ष्म कण, वाहनों से होनेवाला उत्सर्जन इन सबकी वजह से वातावरण में एरोसोल्स का स्तर बढ़ता है। सूरज की रौशनी अवशोषण करने वाला ब्लैक कार्बन या कालिख, और सल्फेट और नायट्रेट जैसे मिश्र जो प्रकाश फैलाते हैं, वातावरण में एरोसोल को बढ़ाने के महत्वपूर्ण घटक हैं।

पिछले अध्ययन में वातावरणीय एरोसोल्स में होनेवाले बदलाव, वर्षा के मौसम में होनेवाली ज्यादा या कम वर्षा के लिए इसे जिम्मेदार ठहराया गया है, अब तक इनके सबंधों का पता नहीं चला है, खास तौर पर, इसकी वजह और परिणामों का सम्बन्ध, अवलोकन डेटा भी नहीं कर पाया।

“हमने एक सवाल पूछा था, क्या हम इस सम्बन्ध के परे जा सकते हैं, और मुख्य रूप से अवलोकन डेटा का उपयोग करते हुए एरोसोल्स और मानसून की वर्षा के परिवर्तनों के बीच संबधों को समझने के लिए वातावरण के रूप में एक प्रणाली स्थापित कर सकते हैं?” ऐसा प्रोफेसर मणी भूषण ने कहा।

साइंटिफिक रिपोर्ट्स (नेचर समूह द्वारा प्रकाशित) द्वारा प्रकाशित किये जानेवाले अध्ययन में खोजकर्ताओं ने २००० से २००९ के दौरान सैटलाइट से मिली हुई जानकारी से एरोसोल का स्तर और बादलों के बारे में जानकारी प्राप्त करने के साथ ही धरती पर आधारित उपकरणों के सहारे वर्षा की मात्रा का गणन किया है। उन्होंने इस जानकारी का विश्लेषण करके एरोसोल्स का अस्तित्व और वर्षा की उपस्थिति के बीच के सम्बन्ध में क्षेत्रीय विभिन्नता का अध्ययन किया है।     

मौसम का परिवर्तन का पैटर्न अस्तव्यस्त होने के बावजूद, वो खुद को दोहराने वाली कुछ दृश्य और अदृश्य मूलभूत प्रक्रियाओं का परिणाम है। मौसम वैज्ञानिक वातावरण के अध्ययन को चार हिस्से में विभाजित करते हैं। माइक्रो – मेसो – साइनोप्टिक और –ग्लोबल - जो इन प्रक्रियाओं के आकार और कालावधि पर निर्भर है। बादलों का झुण्ड या झोंके जैसी सूक्ष्मदर्शी घटनाएँ एक किलोमीटर या उससे कम दायरे के एक क्षेत्र में होती है, जब की जागतिक पैमाने पर यही घटनाएँ हजार किलोमीटर से भी अधिक होती है और ये कम से कम एक महीने तक चलती है।   

इस अध्ययन से दस से हजार किलोमीटर के अंतर में फैली हुई मेसोस्केल की प्रक्रियाओं की जाँच भारत के ऐसे इलाकों में की जाती हैं जहाँ एरोसोल का प्रमाण ज्यादा और वर्षा का प्रमाण कम है. इस परिमाण पर, बहती हवा और पानी के बीच की प्रक्रिया, वर्षा का महत्वपूर्ण घटक है। सूरज की गर्मी से धरती की सतह गर्म होती है, बाद में उसके उपर की हवा गर्म होती है। गर्म हवा ऊपर जाते वक्त अपने साथ वाष्पित किया हुआ पानी ले जाती है और ये पानी ठंडा होकर बादलों की बूँदें बनती है। कुछ समय बाद ये बूँदें इकट्ठा होती है और बढ़ते वजन के कारण जमीन पर गिरती हैं ।

मगर एरोसोल का प्रमाण बढ़ने की वजह से वातावरण का नाज़ुक संतुलन बिगड़ जाता है। एरोसोल्स सूरज की रौशनी सोख लेते हैं जिससे जमीन पर पड़ने वाली सूरज की रौशनी कम हो जाती है और जमीन की सतह ठंडी रह जाती है,  जिस परत को एरोसोल्स सोख लेता है वो परत गर्म रहती है। नतीजा, बादलों के रूप में बढ़ने की बजाय पानी का वाष्प भूमि के समान्तर रूप में विभाजित होता है और फ़ैल जाता है। साथ ही, हवा रुक जाती है और हवा और पानी की लंबवत गतिविधि कम जाती है, इसी कारण वर्षा का परिमाण कम  हो जाता है।  

इस अध्ययन के खोजकर्ताओं ने पाया कि अधिक स्तर के एरोसोल वाले क्षेत्रो में एक ही मौसम में सात दिनों से अधिक समय तक बार बार वर्षा  में रूकावट आई। अगर यही स्थिति जारी रहे , तो इस रूकावट की वजह से अकाल पड़ सकता है और अकाल की स्थिति बढ़ सकती है। सूक्ष्म पैमाने पर, वर्षा की एक बूंद का निर्माण, वाष्प के धूल  के एक कण के इर्द गिर्द जमा होने से होता है। खोजकर्ताओं ने ये भी पता लगाया है कि अगर एरोसोल्स का स्तर बढ़ जाये तो बादलों की बूंदों का आकार बदलता है, और इसी वजह से वर्षा कम होती है। हालाँकि, अब तक उन्हें इन दोनों के बीच का परस्पर सम्बन्ध नहीं मिल पाया है।     

इसलिए इस अध्ययन के अनुसार, एरोसोल्स के उच्च स्तरीय क्षेत्रों में, बार बार वर्षा कम होने की वजह, एरोसोल्स द्वारा सूरज की रौशनी सोख लेना है, जिसकी वजह से पानी का वाष्प और हवा की ऊपर की ओर की गतिविधि में रूकावट पैदा हो जाती है, और नमी क्षितिज के समांतर फ़ैल जाती है। एरोसोल्स के बढ़ते हुए स्तर का असर एक ही दिन में हो जाता है और इसका प्रभाव दो या इससे अधिक दिन तक रहता है।

“इस खोज से हम वायु प्रदूषण और वातावरण के परिवर्तन के बीच का सम्बन्ध, क्षेत्रीय मानसून वर्षा के परिवेश में समझ पाए हैं। भविष्य में मानवी गतिविधियों द्वारा एरोसोल्स उत्सर्जन का प्रमाण बढ़ना अपेक्षित है, ऐसे में इस मुद्दे को समझ पाना बहुत जरुरी है। ऐसा प्रोफ़ेसर चंद्रा वेंकटरमण ने जताया।  

इस अध्ययन को सहायता मिली है -भारतीय प्रौद्योगिकी संस्थान, मुंबई, सेंटर ऑफ एक्सेलेंस इन क्लायमेट स्टडीज (आई आई टी बी - सीईसीएस), डिपार्टमेंट ऑफ सायन्स अँड टेक्नॉलॉजी की परियोजना (डीएसटी,), न्यू दिल्ली, भारत ,से।

Section: General, Science, Deep-dive Source:
Mumbai Thursday, 15 November, 2018 - 07:43

Prof. Chandra M. R. Volla, an Associate Professor in the Department of Chemistry, Indian Institute of Technology Bombay, has won the NASI Young Scientist Award 2018 for his research in the field of chemical sciences. His work deals with catalysis, the process of accelerating a chemical reaction by the use of an agent referred to as a catalyst. He shares the award with three other recipients.

The award, instituted by The National Academy of Sciences, India, acknowledges promising researchers by recognising their creativity and excellence in any branch of science and technology in India. The award carries a citation, a medal and Rs. 25,000 in cash. Since 2006, 143 researchers across India have won the prestigious honour.

Prof. Volla and his team have developed novel and highly efficient reactions that use copper as a catalyst to construct molecules for the synthesis of quinoline derivatives. Quinoline is an essential constituent in many pharmaceutical agents.  Similarly, the team developed a convenient and simple method using Rhodium (II) as a catalyst for the synthesis of benzoxazinones and oxadiazoles that find applications in the pharmaceutical industry for their antiviral and anti-inflammatory properties. These new methods play a significant role in minimising the production of hazardous wastes during chemical reactions thereby providing immense scope for green chemistry.

“Developing new methods for the synthesis of heterocyclic derivativeshas been the focus of our work”, says Prof. Volla. Heterocyclic compounds are ring structured molecules with other elements in addition to carbon and hydrogen. They are used in the fields of medicinal chemistry. “The methods are developed purely on academic interest to study the basic reactivity of the chemical model”, he adds, talking about the scope of his research.

Thanking the NASI committee for the award, Prof. Volla attributes this success to his group. “I joined IIT Bombay in October 2014, and since then, the journey has been an excellent one. The credit goes to my group. I see this as a recognition for my students more than me”, he shares.

Although Prof. Volla’s current research is mostly academic without an immediate, tangible application, he wishes to build on it in the coming years. “The basic theme of activities in our lab is catalysis. However, we intend to do application-oriented research through collaborations to address issues that haven’t been resolved for long using catalysis”, he says on the future direction of his work.

One such application-oriented research is the in the field of optimisation of chemical reactions, where it is desired to develop a method that reduces the number of steps.

“Numerous steps in a reaction do not preserve a particular compound and also generate waste in each step. Thus, the resulting products have to be purified in each step, and the wastes generated amount to an environmental hazard. I want to look at how we can bypass these steps as it is beneficial to both industries and academia”, signs off Prof. Volla. 

Section: General, Science, News Source:
Bengaluru Wednesday, 14 November, 2018 - 08:00

Aerosols, like smoke or dust suspended in the lower layers of the atmosphere, can either heat up the planet by trapping solar radiation or cool it by reflecting sunlight into space. Previous research has shown, for example, that absorption of radiation by aerosols can significantly heat the atmosphere over the Bay of Bengal region. This region dramatically influences the Indian summer monsoon; any change in the effect of aerosols can have a critical impact on the local climate.

Little is known, however, about how much aerosols that are present much higher up—above the clouds—contribute to this warming. Their contribution could depend on the amount of cloud cover below them, studies have shown. Some scientists have proposed a tipping point called “critical cloud fraction” (CCF)—the amount of cloud cover at which above-cloud aerosols switch from having a cooling to a warming effect.

Now, scientists at the Indian Institute of Science, Bengaluru, have estimated this CCF value over the Bay of Bengal region, and demonstrated, for the first time, that it changes with the nature and type of aerosols present above the clouds.

“CCF indicates when aerosols above the clouds will change from cooling the earth to heating the earth,” explained Prof. S. K. Satheesh, senior author of the study published in the journal Atmospheric Science Letters published by the Royal Meteorological Society. “Previous investigators had argued that CCF is the same all over the globe. We have shown that this is not the case and it varies on account of changes in chemical composition of aerosols.”

The researchers found that CCF shifted from a higher value during the post-monsoon period (September-November) to less than half of that value during winter (December-February).

Upon investigating further, they found that this shift corresponded to a change in the nature of the aerosols over the region during those periods. In the post-monsoon season, for instance, the aerosols present were those that absorb less sunlight, such as sea salt aerosols. In their presence, a larger cloud coverage will be needed for the aerosols to have a warming effect. 

However, later, in winter, the aerosol composition shifted to those that absorb more solar radiation, such as black carbon and sulfate emissions likely originating from India, China and Myanmar, leading to a lower warming threshold, or CCF value.

The analysis, using data collected for over four years from multiple satellites, was carried out by researchers at the Centre for Atmospheric and Oceanic Sciences and the Divecha Centre for Climate Change at IISc. This study is the first to analyse the nature and influence of above-cloud aerosols over the Bay of Bengal region. The study also demonstrates that it may be possible to estimate aerosol composition in the atmosphere above the clouds using satellite data.

Efforts are on to investigate the potential regional impacts of the shift in CCF, says Prof. Satheesh.


Editor's Note: The above story was originally published on 30 March 2015 by the Science Media Center at IISc and is now republished.

Section: General, Science, Deep-dive Source: Link
Mumbai Tuesday, 13 November, 2018 - 20:04

Scientists develop a carrier that can deliver drugs more efficiently when triggered by ultrasound.

Even though the first medical description of cancer was written in Egypt around 1600 BC, scientists all over the world are still looking at a comprehensive treatment to treat this often-fatal disease. One major challenge is that drugs used in  chemotherapy affects healthy cells too as they do not selectively attack cancer cells, and many of them fail to penetrate into all the cells of a tumour. In a recent study, researchers from the Indian Institute of Technology Bombay (IIT Bombay) have proposed a new method of combination therapy where they can target solid tumours using an ultrasound image guide, deliver the drug deeply, and enhance killing of tumour cells using a naturally occurring lipid, all at the same time.

Cancer is a complex disease, with variations across individuals. Often, one solution to treat cancer does not fit all. A combination therapy involves using multiple complementary approaches to address a disease condition.  This provides a better chance to tackle the disease across the population. The researchers of the current study, led by Prof. Rinti Banerjee from the Department of Biosciences and Bioengineering, IIT Bombay, have proposed one such combination therapy. Simply put, this combination looks like two balls---a small and a big---stuck together. The smaller ball is the capsule that contains the drug and the bigger one, double the size, is a gas bubble. The bubble is about 500 nanometers, and is known as a “nanobubble” and the drug carrier is called “nanocapsule”. Each of these components act synergistically in treating cancer.

The nanobubble has two purposes. It can be detected by ultrasound imagery. This has a potential for image guided cancer therapy, where it is possible to track its location as it traverses through the blood streams. The second purpose is to enhance the delivery of the drug carried in the capsule. When ultrasound is applied near the tumor cells, these nanobubbles expand and contract, and eventually burst. This helps in loosening  up the tumor tissue. The capsules can then easily penetrate the tumor and deliver the drug deep inside.  The nanobubble, in a sense, clears the way, sacrificing itself, for the nanocapsule.

The capsule also has two ways of controlling cancer.  The capsule shell is made of lipids, a naturally occurring essential biomolecule in cell membranes. The capsules called liposomes, and by nature they are biocompatible. These capsules have to be very small (about 200 nanometers) so that they can penetrate through the gaps between the cells. The anti-cancer drug is embedded inside the capsule. Prof. Banerjee’s group have used Paclitaxel, a commonly used chemotherapeutic drug for a wide range of cancers. In addition, they have also used a naturally occuring lipid (phosphatidylserine) which is responsible for cell death.

While each of the above principles and methods have been known to exist independently, the key innovation of Prof. Banerjee’s group is to combine these together and provide a generic platform that can be applied to various other therapeutics.

“To the best of our knowledge this is the first time a smart combination therapy with a pro-apoptic biomolecule, a drug, and nanobubbles have been used together”, says Prof. Banerjee. The research has been recently published in the journal Scientific Reports.

The group has carried out experiments with this new therapy in lab grown cells (in-vitro), as well as in animals (in-vivo) to test the anti-tumor efficacy. The results showed that the combination therapy with ultrasound was more effective than any other subcombination with one or more components left out. The drug was taken up quickly by the cancer cells, caused higher amounts of drug accumulation in the tumor and had higher effectiveness in killing the cancer cells or regressing the tumor.  The animals were also found to have 100% survival rate in the combination, than otherwise. Even the ultrasound images around the tumor tissue were obtained with a  significantly better contrast compared to the existing methods (SonoVue).

Talking about how this combination can help fight cancer, Prof Banerjee explains, "This research presents an image-guided, ultrasound trigger-responsive platform for improved tumour cell targeting along with real-time monitoring of the disease.”

This innovation holds  potential as an adjunct anti-cancer therapy and paves the way for progress in ultrasound image-guided and triggered cancer therapeutics. The overall increase in efficacy and the better visualisation provided by the nanobubbles could help further customise the treatment. 

Section: General, Science, Technology, Health, Deep-dive Source:
Bengaluru Tuesday, 13 November, 2018 - 19:23

The Infosys Science Foundation (ISF) has announced the winners of the Infosys Prize 2018 today, 13 November 2018. Among the winners who are in Indian institutes are two Professors from the Indian Institute of Science, Bengaluru, and one each from the Jawaharlal Nehru University, New Delhi and the Tata Institute of Fundamental Research, Mumbai.

The Infosys Prize is presented annually in six categories— Engineering and Computer Sciences, Humanities, Life Sciences, Mathematical Sciences, Physical Sciences, and Social Sciences. The prize includes a gold medal, a citation and prize money of USD 100,000.

Professor Navakanta Bhat, Chairperson, Centre for Nano Science and Engineering at IISc has been awarded in the Engineering and Computer Sciences category. His contributions include designing novel transistors, biosensors and ultra-precise gas sensors for space and environmental monitoring. Some of his newsworthy research, which have been covered by Research Matters, can be found here and here.

Professor Kavita Singh, Dean, School of Arts & Aesthetics, Jawaharlal Nehru University, New Delhi has been awarded the prize in Humanities. Prof. Singh has made immense contributions in the study of Mughal, Rajput and Deccan art, and the historical function and role of museums.

In the Life Sciences category, Professor Roop Mallik, Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai has received the award. He was considered for this award for his pioneering works on molecular motor proteins, crucial for the functioning of cells. One of his works on how insulin could help us digest fats has been covered by Research Matters here.

Prof. Nalini Anantharaman, Professor and Chair of Mathematics, Institute for Advanced Study, University of Strasbourg, France, has been selected for the Prize in the Mathematical Sciences category for her work on quantum physics.

“The quantum world is one of the deepest secrets of the universe and mathematics is the language that helps us understand this world. Mathematicians and physicists have been trying for decades to unravel the mysteries of this subatomic world. Prof. Anantharaman’s work impressively explores the deep relationship between classical and quantum systems and the unexpected use of entropy to prove some of the hard results,” reads a press release by Infosys.

In the Physical Sciences category, Professor S.K. Satheesh, Centre for Atmospheric & Oceanic Sciences, IISc, and Director, Divecha Centre for Climate Change has received this honour. Prof Satheesh has been selected for this award for his research work on climate change.

The Infosys Prize 2018 for Social Sciences category has been awarded to Professor Sendhil Mullainathan, University Professor, Professor of Computation and Behavioral Science, and George C. Tiao Faculty Fellow, The University of Chicago Booth School of Business for his contributions in behavioural economics. The press release from Infosys informs that Prof. Mullainathan’s research has had a substantial impact on diverse fields of development, public finance, corporate governance and policy design.

“Infosys Prize laureates have achieved prestigious milestones in their domains, and the ISF believes that this year’s winners will continue to raise the bar for science and research over the next decade. By recognizing these outstanding researchers and celebrating their achievements, the Infosys Prize aims to inspire young minds to explore science as a career option and advance innovation in the country,” reads a press release published by Infosys.

Section: General, Science, News Source:

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