Tallinn University of Technology

www.ttu.ee
Tallinn, Estonia

Established in 1918, Tallinn University of Technology is the only technical university in Estonia. TUT, in the capital city of Tallinn, is the nation’s leading academic institution in engineering, business, and public administration. TUT has colleges in Tallinn, Tartu, Kuressaare and Kohtla-Järve. Despite the similar names, Tallinn University and Tallinn University of Technology are separate institutions. Wikipedia.

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News Article | April 27, 2017
Site: globenewswire.com

Supervisory board of Nordecon AS decided on its meeting held on 26 April 2017 to appoint two new management board members as of 01 May 2017: Maret Tambek will be responsible for financial management and support services of the group and Priit Luman’s responsibility will be the group’s activities in the export markets. Maret Tambek started working for Nordecon Infra AS as a financial manager in 2007. She assumed the position of head accountant of the group in spring 2010 and as of July 2014, Maret Tambek acts as a financial director of Nordecon AS. Previously, Maret worked for KPMG Baltics AS as an auditor for eleven years. She worked as a specialist for the Bank of Estonia from 1992 to 1996. Maret graduated from Tallinn University of Technology in the field of Management and Planning of Manufacturing in 1989. Maret is certified public accountant and member of the Estonian Auditors’ Association. Maret Tambek does not own the shares of Nordecon AS. Priit Luman has held different construction management related positions in Nordecon AS since 2006. Starting from 2013 he is the head of the buildings construction division. Priit graduated from Tallinn University of Technology in Civil and Building Engineering in 2010, obtaining a cum laude Master’s degree in Science in Engineering. Starting from 2017 Priit studies in the EMBA program of Aalto University. Priit Luman has been issued a Level V Diploma Civil Engineer by the Estonian Association of Civil Engineers. Priit Luman owns 200 shares of Nordecon AS. Nordecon (www.nordecon.com) is a group of construction companies whose core business is construction project management and general contracting in the buildings and infrastructures segment. Geographically the Group operates in Estonia, Ukraine, Finland and Sweden. The parent of the Group is Nordecon AS, a company registered and located in Tallinn, Estonia. In addition to the parent company, there are more than 10 subsidiaries in the Group. The consolidated revenue of the Group in 2016 was 183 million euros. Currently Nordecon Group employs close to 700 people. Since 18 May 2006 the company's shares have been quoted in the main list of the NASDAQ Tallinn Stock Exchange.


A device for preparing a continuous nanofibrous yarn comprises an electrospinning chamber, comprising at least one first opening in the upper region of said chamber for receiving gas and a second opening in the bottom region of said chamber for discharging gas and said yarn; means for creating helical movement of gas within said electrospinning chamber; means for introducing a plurality of nanofibres into said electrospinning chamber, wherein said nanofibres are twisted together by said helical movement of gas.


Patent
Tallinn University of Technology | Date: 2017-06-07

A substrate for and a method to purify fluids, especially of biological origin, is provided here. The substrate has one dimensionally self-organized or self-assembled inorganic nanofibers. The fibers have diameter below 100 nm and ultra-high aspect ratio (length: diameter > 100,000:1). The substrate has a high porosity (over 50%) due to week bonds between adjacent fibers. The substrate is capable of withstanding temperatures over 350C. A method to purify fluids is also provided.


Patent
Tallinn University of Technology and University of Tartu | Date: 2016-08-27

A tropomyosin receptor kinase (Trk) antagonist having a compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein R1 is CH_(3), R2 is OCH_(3), R3 is SO_(2)N(CH_(3))_(2), and R4 is H; or R1 is CH_(3), R2 is OH, R3 is SO_(2)N(CH_(3))_(2), and R4 is H.


News Article | May 12, 2017
Site: www.gizmag.com

A Prince Rupert's drop looks like a glass tadpole from a beginner's crafts festival, but it's so strong it can take a hammer hit without breaking. That would be impressive enough, but if you break its tail, which can be done with finger pressure, the drop explodes into powder. The reason for this has mystified scientists for 400 years, but a team from Purdue University, the University of Cambridge, and Tallinn University of Technology in Estonia finally has an answer. Also called Batavian tears, Prince Rupert's drops were discovered in the 17th century and became famous when Prince Rupert of Bavaria presented five of the curiosities to Charles II of England. These were turned over to the Royal Society for study in 1661, yet despite four centuries of research, the secret of the drop's combination of great strength and self-destructive fragility remained elusive. The drops are made by taking red hot blobs of molten glass with a high thermal expansion coefficient, like soda-lime or flint glass, and dropping them into a jar of cold water. The molten glass instantly solidifies into the characteristic tailed drop shape in a quenching process similar to that used to make the tempered glass for modern smartphone screens, which wasn't discovered until the 19th century. Along with Purdue professor of industrial engineering Srinivasan Chandrasekar, team leader Hillar Aben of Tallinn University used integrated photoelasticity to investigate the drops. This is a technique where a transparent 3D object is suspended in an immersion bath and polarized light is passed through it. The alterations in the light's polarization inside the object show up as rainbow bands that correspond to stress lines. Previous work by Chandrasekar and Cambridge physicist Munawar Chaudhri in 1994 showed that by filming an exploding drop at almost one million frames per second, it could be seen disintegrating as cracks propagated within it at over 4,000 mph (6,437 km/h) when the tail was snipped. Focusing on the head of the drop instead of the tail, the current study found that the compressive stresses in the glass are about 50 tons per square inch, which gives it the strength of some steels. According to the team, this is because the outside of the drop cools faster than the inside. This turns the outside into a layer of powerful compressive forces pushing inward. These are balanced out by the tensile or pulling forces inside the drop. So long as these forces remain in balance, the drop remains stable and can withstand tremendous punishment. Normally, because glass is a supercooled liquid rather than a solid, any cracks in the surface propagate at the speed of sound through a glass object, breaking it. But in a Prince Rupert's drop, the interface between the inner and outer regions deflects the forces sideways, so the crack can't propagate. However, if the tail is broken, The shallow cracks in the tail shoot parallel to the axis of the drop, deep into the head, and into the interface. The damage is so great that the balanced forces are released, causing the drop to explode. "The tensile stress is what usually causes materials to fracture analogous to tearing a sheet of paper in half," says Purdue postdoctoral associate Koushik Viswanathan. "But if you could change the tensile stress to a compressive stress, then it becomes difficult for cracks to grow, and this is what happens in the head portion of the Prince Rupert's drops." The research was published in Applied Physics Letters and its findings are discussed in the video below.


News Article | May 12, 2017
Site: www.chromatographytechniques.com

Small glass structures resembling tadpoles that can withstand the blows of a hammer and yet burst into powdery dust by simply snipping their threadlike tails have been a source of fascination and mystery since they were discovered in the 17th century. Now an international research team has pinpointed the source of the bizarre shatter-resistant behavior behind Prince Rupert’s drops. The work was a collaboration of researchers from Purdue University, the University of Cambridge in the UK and Tallinn University of Technology in Estonia. “Since the seventeenth century, famous scientists and natural philosophers have been trying to understand the exceptional properties of these drops,” said Srinivasan Chandrasekar, a Purdue professor of industrial engineering and director of the university’s Center for Materials Processing and Tribology. “Rupert’s drops have been a curiosity for about 400 years.” Germany’s Prince Rupert brought five of the enigmatic drops to England and presented them to King Charles II, who became interested in their extraordinary properties. “On one hand, the head can withstand hammering, and on the other hand, the tail can be broken with just the slightest finger pressure, and within a few microseconds the entire thing shatters into fine powder with an accompanying sharp popping noise,” Chandrasekar said. In new findings, the researchers used a technique called integrated photoelasticity, pioneered by Tallinn University scientist Hillar Aben, who is lead author of a paper published in the journal Applied Physics Letters. The measurements reveal the complex stress distribution in the drop as rainbow-colored bands when viewed through polarizing filters. Mathematical techniques, similar to those used in reconstructing 3-D information from medical CT scans, are then used to precisely recover the stresses based on the band patterns. The new research is an extension of work performed more than 20 years ago by Chandrasekar and Cambridge physicist Munawar Chaudhri, who is the corresponding author on the Applied Physics Letters paper. In their 1994 work, they showed, using high-speed photographic analysis of drop disintegration at nearly 1 million frames per second, individual cracks accelerating from the drop’s tail toward the head at more than 4,000 mph. This explained their explosive disintegration when the tail was snipped off, an intriguing property of the drops. While the 1994 research paper focused on the tail, the new research concentrates on the head’s amazing shatter-resistant behavior. Findings showed the high strength of the head comes from compressive stresses calculated at around 50 tons per square inch, making them as strong as some grades of steel. The drops, also known as Batavian tears, are made of glass having a “high thermal expansion coefficient,” which is needed to create the compressive residual stresses that provide the shatter-resistance. They are produced by dropping red hot blobs of molten soda-lime or flint glass into cold water, quickly cooling in a process called quenching. It is similar to processes used to make shatter-resistant glasses like those in today’s cellphone screens. “The first patents to strengthen glass were in the 19th century, so there was a time lag of more than 200 years,” Chandrasekar said. On cooling down and solidifying, the drops form in a tadpole shape with bulbous head and long threadlike tail, which combined, are about four inches long. The surfaceof the drops cools faster than the interior, producing a combination of compressive stresses on the surface, and compensating tensile – or pulling - stresses in the interior of the drops. “The tensile stress is what usually causes materials to fracture analogous to tearing a sheet of paper in half,” said Purdue postdoctoral associate Koushik Viswanathan, a co-author of the paper. “But if you could change the tensile stress to a compressive stress, then it becomes difficult for cracks to grow, and this is what happens in the head portion of the Prince Rupert’s drops,” he said. As recently as 2013, published findings have proposed incorrect solutions to the riddle of the drop’s shatter-resistant strength. The research paper was authored by Aben and fellow Tallinn University of Technology researchers Johan Anton and Marella Ois; Purdue’s Viswanathan and Chandrasekar; and Cambridge’s Chaudhri. The work was supported by Estonian Research Council, the National Science Foundation and the U.S. Army Research Office.


News Article | May 9, 2017
Site: phys.org

In the 17th century, Prince Rupert from Germany brought some of these glass drops to England's King Charles II, who was intrigued by their unusual properties. While the head of the drop is so strong that it can withstand the impact of a hammer, the tail is so fragile that bending it with your fingers will not only break the tail, but cause the entire droplet to instantly disintegrate into a fine powder. Prince Rupert's drops are easily made by dropping red hot blobs of molten glass into water. Although researchers have tried to understand what causes the unusual properties of these drops for many years, it was not until recently that modern technology has allowed researchers to thoroughly investigate them. In 1994, S. Chandrasekar at Purdue University and M. M. Chaudhri at the University of Cambridge used high-speed framing photography to observe the drop-shattering process. From their experiments, they concluded that the surface of each drop experiences highly compressive stresses, while the interior experiences high tension forces. So the drop is in a state of unstable equilibrium, which can be easily disturbed by breaking the tail. One open question, however, is how the stresses are distributed throughout a Prince Rupert's drop. Understanding the stress distribution would help to more fully explain why the heads of these drops are so strong. To do this, Chandrasekar and Chaudhri began collaborating with Hillar Aben, a professor at Tallinn University of Technology in Estonia. Aben specializes in determining residual stresses in transparent three-dimensional objects, such as Prince Rupert's drops. In the new study published in Applied Physics Letters, Aben, Chandrasekar, Chaudhri, and their coauthors have investigated the stress distribution in Prince Rupert's drops using a transmission polariscope, which is a type of microscope that measures the birefringence in an axi-symmetrical transparent object, such as a Prince Rupert's drop. In their experiments, the researchers suspended a Prince Rupert's drop in a clear liquid, and then illuminated the drop with a red LED. Using the polariscope, the researchers measured the optical retardation of the light as it traveled through the glass drop, and then used the data to construct the stress distribution throughout the entire drop. The results showed that the heads of the drops have a much higher surface compressive stress than previously thought—up to 700 megapascals, which is nearly 7,000 times atmospheric pressure. This surface compressive layer is also thin, about 10% of the diameter of the head of a drop. As the researchers explain, these values give the droplet heads a very high fracture strength. In order to break a droplet, it's necessary to create a crack that enters the interior tension zone in the drop. Since cracks on the surface tend to grow parallel to the surface, they cannot enter the tension zone. Instead, the easiest way to break a drop is to disturb the tail, since a disturbance in this location allows cracks to enter the tension zone. Overall, the researchers believe that the results finally explain the great strength of Prince Rupert's drops. "The work has fully explained why the head of a drop is so strong," Chaudhri told Phys.org. "I believe we have now solved most of the main aspects of this area. However, new questions may emerge unexpectedly." More information: H. Aben et al. "On the extraordinary strength of Prince Rupert's drops." Applied Physics Letters. DOI: 10.1063/1.4971339


News Article | May 12, 2017
Site: www.chromatographytechniques.com

Small glass structures resembling tadpoles that can withstand the blows of a hammer and yet burst into powdery dust by simply snipping their threadlike tails have been a source of fascination and mystery since they were discovered in the 17th century. Now an international research team has pinpointed the source of the bizarre shatter-resistant behavior behind Prince Rupert’s drops. The work was a collaboration of researchers from Purdue University, the University of Cambridge in the UK and Tallinn University of Technology in Estonia. “Since the seventeenth century, famous scientists and natural philosophers have been trying to understand the exceptional properties of these drops,” said Srinivasan Chandrasekar, a Purdue professor of industrial engineering and director of the university’s Center for Materials Processing and Tribology. “Rupert’s drops have been a curiosity for about 400 years.” Germany’s Prince Rupert brought five of the enigmatic drops to England and presented them to King Charles II, who became interested in their extraordinary properties. “On one hand, the head can withstand hammering, and on the other hand, the tail can be broken with just the slightest finger pressure, and within a few microseconds the entire thing shatters into fine powder with an accompanying sharp popping noise,” Chandrasekar said. In new findings, the researchers used a technique called integrated photoelasticity, pioneered by Tallinn University scientist Hillar Aben, who is lead author of a paper published in the journal Applied Physics Letters. The measurements reveal the complex stress distribution in the drop as rainbow-colored bands when viewed through polarizing filters. Mathematical techniques, similar to those used in reconstructing 3-D information from medical CT scans, are then used to precisely recover the stresses based on the band patterns. The new research is an extension of work performed more than 20 years ago by Chandrasekar and Cambridge physicist Munawar Chaudhri, who is the corresponding author on the Applied Physics Letters paper. In their 1994 work, they showed, using high-speed photographic analysis of drop disintegration at nearly 1 million frames per second, individual cracks accelerating from the drop’s tail toward the head at more than 4,000 mph. This explained their explosive disintegration when the tail was snipped off, an intriguing property of the drops. While the 1994 research paper focused on the tail, the new research concentrates on the head’s amazing shatter-resistant behavior. Findings showed the high strength of the head comes from compressive stresses calculated at around 50 tons per square inch, making them as strong as some grades of steel. The drops, also known as Batavian tears, are made of glass having a “high thermal expansion coefficient,” which is needed to create the compressive residual stresses that provide the shatter-resistance. They are produced by dropping red hot blobs of molten soda-lime or flint glass into cold water, quickly cooling in a process called quenching. It is similar to processes used to make shatter-resistant glasses like those in today’s cellphone screens. “The first patents to strengthen glass were in the 19th century, so there was a time lag of more than 200 years,” Chandrasekar said. On cooling down and solidifying, the drops form in a tadpole shape with bulbous head and long threadlike tail, which combined, are about four inches long. The surfaceof the drops cools faster than the interior, producing a combination of compressive stresses on the surface, and compensating tensile – or pulling - stresses in the interior of the drops. “The tensile stress is what usually causes materials to fracture analogous to tearing a sheet of paper in half,” said Purdue postdoctoral associate Koushik Viswanathan, a co-author of the paper. “But if you could change the tensile stress to a compressive stress, then it becomes difficult for cracks to grow, and this is what happens in the head portion of the Prince Rupert’s drops,” he said. As recently as 2013, published findings have proposed incorrect solutions to the riddle of the drop’s shatter-resistant strength. The research paper was authored by Aben and fellow Tallinn University of Technology researchers Johan Anton and Marella Ois; Purdue’s Viswanathan and Chandrasekar; and Cambridge’s Chaudhri. The work was supported by Estonian Research Council, the National Science Foundation and the U.S. Army Research Office.


The present invention relates to nickel oxide/ nickel aluminate nanofibers based on NiO/NiAl_(2)O_(4) composition of a high structural thermal stability, high aspect ratio (10^(4)), and a diameter of the fiber less than 100 nanometer. The NiO/NiAl_(2)O_(4) structure comprises the following compositions in percentage by weight: up to 40 % of NiO and over 60 % of NiAl_(2)O_(4), wherein NiO is dispersed along the NiAl_(2)O_(4) nanofibers homogeneously.


Patent
Tallinn University of Technology | Date: 2016-04-19

Method and device for impedance analyzer with binary excitation with improved accuracy, where the non-idealities of the sampling and preprocessing of the response signal (including aliasing effects) are taken into account by using of the overall system model with equivalent circuit diagrams of the analyzed object and the model of the preliminary analysis of the response signal. The analysis result is the equivalent circuit diagram with component values with the best match of the overall model analysis and of the preliminary analyze of the response signal. Further, the analysis result can be the impedance frequency characteristic or the classifier of the analyzed object. It could be reasonable to use the pre-calculated function (e.g. in the form of the look-up-table) for matching the results of the over-all model against the preliminary analyzed results of the response signal.

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