Exploring the characteristics of viscoelastic fluids

first_img Copyright 2010 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Teran works in the Department of Mathematics at the University of California, Los Angeles. He collaborated with Lisa Fauci at Tulane University and Michael Shelley at New York University to create a computer model depicting what happens when a free swimmer moves through a viscoelastic fluid. Their results can be seen in Physical Review Letters: “Viscoelastic Fluid Response Can Increase the Speed and Efficiency of a Free Swimmer.”“Our experiment is a computer simulation that is more representative of the real medium than simpler models relying on a more standard Newtonian fluid. The simpler models work out nice mathematically, but they are not a very accurate description of the physics that are happening,” Teran explains.With the simpler models, a wave is often depicted as moving through the fluid, with no head or tail. Additionally, these simpler models only account for the viscosity of the fluids, rather than including an element of elasticity. Teran and his peers added a free swimmer with a head and a tail, and included information representing tail undulations. They also used a viscoelastic Boger fluid in their calculations to more accurately represent the actual conditions.“What we found defies conventional wisdom,” Teran says. “When you think of a viscous fluid, like mud or honey, the fact that it is hard to swim through comes to mind. It’s inherently resistant to shear, and it is more likely to stop you. If you add elasticity, it seems like it should be even harder to swim through, since a viscoelastic fluid has a memory and resists changing shape. However, we found that a free swimmer ends up going faster in a viscoelastic fluid than a just plain viscous fluid.”The answer lies in the tail motion of the swimmer. “If you accentuate the tail motion, as seen in a lot of microscopic swimmers, you see them able to move faster because they can use the elasticity in the fluid to sort of push off. It’s leverage for use in biology.”Teran believes that the work he had done with Fauci and Shelley has implications for a number of biological applications. “The most obvious is in reproduction and fertility,” he points out. “Understanding how sperm locomote could be helpful in figuring out how to aid in reproduction. Teran also insists that understanding how these fluids work could have other uses in some engineering and biological functions. “There are a wide range of applications for fluids, and understanding their dynamics could be useful.”Next, Teran, Fauci and Shelley hope to improve their model. “So far, we have only done this in a two dimension model,” Teran says. “We also used a Boger fluid, which is a kind of crude viscoelastic fluid. It’s simplistic and easier to tune to a given physical setting. But now that we know our model works, we want to ramp it up, improving the computer code. Three dimensional modeling is one natural extension, as is using a more complex fluid to even more accurately represent real world conditions.”Hopefully, a better model will provide scientists and mathematicians with a better understanding of fluid dynamics. “Fundamentally, this could be a real help to science,” Teran says, “and there are applications that could come out of this better understanding.” Citation: Exploring the characteristics of viscoelastic fluids (2010, February 4) retrieved 18 August 2019 from https://phys.org/news/2010-02-exploring-characteristics-viscoelastic-fluids.html Explore further More information: Joseph Teran, Lisa Fauci, Mischael Shelley, “Viscoelastic Fluid Response Can Increase the Speed and Efficiency of a Free Swimmer,” Physical Review Letters (2010). Available online: link.aps.org/doi/10.1103/PhysRevLett.104.038101center_img How to Rip a Fluid (PhysOrg.com) — There are many microorganisms out there, navigating through complex biological fluids. “One of the most common migrations takes place with spermatozoa as it navigates the female reproductive tract,” Joseph Teran tells PhysOrg.com. “But there are other organisms that move through difficult environments as well, and we want to gain a better understanding of how these organisms move through viscoelastic fluids, like those found in biology.” This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Vehicle shock absorber recovers energy from bumps in the road

first_img(PhysOrg.com) — In the past decade, regenerative braking systems have become increasingly popular, recovering energy that would otherwise be lost through braking. However, another energy recovery mechanism that is still in the research stages is regenerative suspension systems. This technology has the ability to continuously recover a vehicle’s vibrational energy dissipation that occurs due to road irregularities, vehicle acceleration, and braking, and use the energy to reduce fuel consumption. Citation: Vehicle shock absorber recovers energy from bumps in the road (2010, March 17) retrieved 18 August 2019 from https://phys.org/news/2010-03-vehicle-absorber-recovers-energy-road.html Copyright 2010 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. More power from bumps in the road: Energy-harvesting shock absorbers Explore further In the regenerative shock absorber, a smaller magnetic tube slides inside a larger, hollow coil tube, producing a magnetic flux. The researchers estimate that, for typical driving conditions, the system can improve fuel efficiency by 2-10%. Image credit: Zuo, et al.center_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. When placed in the vehicle suspension, vibrations in the suspension cause the coil tube to move relative to the magnetic tube. As the copper coils move inside this magnetic field, a voltage is generated. The electricity can then be used to recharge the vehicle’s battery.By recovering the vehicle’s vibrational energy and using it to drive the vehicle, the researchers hope that regenerative suspension system technology will be able to increase fuel efficiency and cut down on pollution. They note that, in the US, automobiles are a major source of several pollutants in the atmosphere, including 70% of the carbon monoxide, 45% of the nitrogen oxide, and 34% of the hydrocarbons. Further, fuel efficiency has lots of room for improvement: currently, only 10-16% of a vehicle’s fuel energy is used to drive the vehicle, i.e. to overcome the resistance from road friction and air drag. The rest is lost due to braking, vibrational energy dissipation, and other forms of loss.“Regenerative braking harvests large amount of power in a very short time, in an intermittent manner,” Zuo said. “However, the regenerative shock absorbers can harvest the power in a continuous way. On the smooth highway road, the regenerative shock absorbers can improve the fuel efficiency by 2%, and on bumpy roads up to 10% increase can be expected.”In the future, the researchers plan to increase the energy density and efficiency of the system by further increasing the magnetic field intensity and improving the harvesting electrical circuit. The New York State Energy Research and Development Authority (NYSERDA) will provide funding to support Zuo on this research and development work.“We believe there is still room for improvement in the overall design of the regenerative system, and we are working on such improvement under funding support from NYSERDA,” Zuo said. More information: Lei Zuo, Brian Scully, Jurgen Shestani, and Yu Zhou. “Design and characterization of an electromagnetic energy harvester for vehicles suspensions.” Smart Mater. Struct. 19 (2010) 045003 (10pp). Doi:10.1088/0964-1726/19/4/045003 In a recent study, Professor Lei Zuo, Brian Scully, Jurgen Shestani, and Yu Zhou, all mechanical engineers from the State University of New York at Stony Brook, have designed and tested a retrofit regenerative shock absorber that recovers a vehicle’s vibrational energy. The researchers built a 1:2 scale prototype of the regenerative shock absorber, and demonstrated its ability to harvest 2-8 watts of power during typical driving conditions at a speed of about 45 mph. They predict that a full-scale system on a four-wheel car should be able to recover up to 256 watts under these driving conditions.“For typical driving conditions, we are predicting the ability to harvest approximately 64 watts per wheel, for a total of approximately 256 watts,” Zuo told PhysOrg.com. “This value increases considerably when the system is used on irregular roads.”The purpose of the shock absorber in a vehicle’s suspension system is to reduce the vehicle’s vibration by dissipating the vibrational energy. About 10 years ago, researchers began looking into recovering the vibrational energy using various magnetic devices. In general, these systems work by first absorbing the kinetic energy of suspension vibration between the wheel and a sprung mass, and then converting that energy into useful electric power. Zuo and his team’s shock absorber consists of two tube-like components: a smaller magnetic tube slides inside a larger, hollow coil tube. The coil component is made of copper coils wound around a plastic delrin tube, while the magnetic component is made of ring-shaped magnets separated by ring-shaped magnetically permeable spacers. The magnets are aligned with like-poles facing each other to produce a radially emitted magnetic flux. The magnetic tube is also surrounded by a high magnetically permeable material in order to further “pull” the magnetic flux outward. As Zuo explained, having a high magnetic flux is key to the design. “The power we regenerate is proportional to the square of the magnetic flux across the coils,” he said. “Therefore, if we increase the flux by two times, the peak power output will increase by four times.”last_img read more

Direct imaging of active orbitals in quantum materials

first_imgIn their experiment, Tjeng ad his colleagues used synchrotron radiation as an ‘undulator’ beamline, to deliver monochromatic x-rays with high intensities. They directed the x-ray beam at a sample, specifically a single crystal; then they detected and analyzed the scattered x-rays.”By looking at the intensity of a particular atomic process (in our case ‘the 3s-to-3d excitation’) as a function of the orientation of the sample with respect to the transferred photon-momentum and by displaying these intensities on a polar plot, we obtained a direct image of the 3d orbital.,” Tjeng said.In their study, Tjeng and his colleagues were able to demonstrate the effectiveness, both in terms of power and accuracy, of the imaging technique proposed by them. They successfully applied their method on a textbook example, the x2y2/3z2-r2 orbital of the Ni2+ ion in a NiO single crystal. “By being able to directly image the orbitals that are active in a material, we will have a better and more precise insight in the behavior of the electrons that are responsible for the properties of the material,” Tjeng said. This is especially important for the design of new materials with new or optimized properties, which is highly desired by both the physics and chemistry research communities.” Tjeng and his colleagues have presented a tangible and efficient alternative to current methods for studying orbitals in quantum materials, which could ultimately enhance research in both physics and chemistry. In their future work, they plan to use their technique to study other complex materials. In addition, they would like to improve the apparatus and instruments employed by their method, so that it can become a standard source of measurement, such as single crystal x-ray or neutron diffraction measurement. © 2019 Science X Network A first for quantum physics: Electron orbitals manipulated in diamonds Citation: Direct imaging of active orbitals in quantum materials (2019, April 17) retrieved 18 August 2019 from https://phys.org/news/2019-04-imaging-orbitals-quantum-materials.html “Initially, all of this was theory,” Tjeng said. “We then set out to do the experiment, investing and upgrading an existing instrument at the PETRA-III synchrotron facility, in order to have sufficient signal, considering that this is a very photon hungry experiment. After some efforts, we were indeed able to observe the signal and the results that we had envisioned.” This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. In a recent study published in Nature Physics, a team of researchers at Max Planck Institute Dresden, Heidelberg University, University of Cologne, and DESY- Hamburg attempted to image a material’s active orbitals directly in real space, without any modeling. The imaging technique they devised is based on s-core level and non-resonant inelastic X-ray scattering.”We are interested in how materials attain their properties,” Hao Tjeng, one of the researchers who carried out the study, told Phys.org. “We want to know how these can be explained on the basis of the behavior of the electrons in the materials. We are mostly interested in transition metal (3d, 4d, 5d) and rare-earth-based (4f) materials, since they offer a wealth of fascinating and tunable properties, important for fundamental science and for numerous other applications.”When they first started working on their study, Tjeng and his colleagues knew that the quantum mechanical equations that they would need to solve were unsolvable, as the relevant calculations would take an infinite amount of time. They thus realized that it would be far more practical and useful to image the orbitals in practical experiments. “Usually, in order to determine what type of quantum mechanical states are realized in a material, one carries out spectroscopic measurements,” Tjeng explained. “These have their merits, but also their limitations: one still need to do calculations to extract the information, and quite often the results are not accurate or reliable. We were thus looking for a new method that can provide a direct image of the quantum mechanical state straight for the experiment. Maurits Haverkort and I realized that inelastic x-ray scattering could provide such an opportunity.”Using X-rays and large momentum transfers, the researchers were able to observe atomic transitions in the sample that would otherwise be forbidden in standard experiments, such as x-ray or optical absorption spectroscopy. Haverkort and Tjeng realized that by making a transition from a spherical atomic state (e.g. 3s) they could attain the shape of a 3d orbital with respect to the photon momentum transfer. Credit: Yavas et al. Journal information: Nature Physics In quantum materials based on transition metals, rare-earth and actinide elements, electronic states are characterized by electrons in orbitals d and f, combined with the solid’s strong band formation. Until now, to estimate the specific orbitals that contribute to the ground state of these materials and determine their physical properties, researchers have primarily relied on theoretical calculations and spectroscopy methods. More information: Hasan Yavaş et al. Direct imaging of orbitals in quantum materials, Nature Physics (2019). DOI: 10.1038/s41567-019-0471-2 Credit: Yavas et al. Explore furtherlast_img read more

A closer look a magnesium shows very small samples are much more

first_img More information: Bo-Yu Liu et al. Large plasticity in magnesium mediated by pyramidal dislocations, Science (2019). DOI: 10.1126/science.aaw2843 Citation: A closer look a magnesium shows very small samples are much more ductile than thought (2019, July 9) retrieved 18 August 2019 from https://phys.org/news/2019-07-closer-magnesium-small-samples-ductile.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further Making lighter vehicles with magnesium alloys Journal information: Sciencecenter_img A team of researchers affiliated with several institutions in China and the U.S. has found that very small samples of magnesium are much more ductile than thought. In their paper published in the journal Science, the group describes their study of the metal using an electron microscope and what they found. Gwénaëlle Proust, with the University of Sydney, has published a Perspective piece on the work done by the team in the same journal issue. © 2019 Science X Network As engineers around the world look for ways to make more efficient cars, planes and other vehicles, they are studying new, lighter materials. One such material, magnesium, is interesting because it is just as strong as aluminum, but 35 percent lighter. Up until now, the metal has rarely been used because it is too difficult to process into parts. It is also much less resistant to corrosion. Still, interest in the metal persists—many in the field believe it is only a matter of finding the right elements to mix with it. In this new effort, the researchers report that they have found very small samples of magnesium are more ductile than previously thought.The reason that magnesium is less amenable to conformity than other bendable metals is because of the way its atoms arrange themselves. Atoms such as aluminum are arranged in a cubic structure, which makes it relatively easy to make desired deformities. Magnesium atoms, in sharp contrast, are arranged in a hexagonal pattern. Prior research has shown that when a metal such as aluminum is deformed at room temperature, atoms are displaced along a line in the crystal allowing for dislocations in multiple ways. With magnesium, the possibilities are more limited. To better understand those limitations, the researchers used electron microscopy mechanical testing techniques on a micron-sized sample of magnesium. The technique allowed them to see exactly what happened while applying sheer forces at the atomic level and at room temperature.The researchers report that the crystal showed surprising ductility—they were able to force dislocations along two planes, something not seen in larger samples. They plan to keep working with the metal to see if they can find a way to force similar dislocations in larger samples—possibly paving their way for use in real-world applications. In situ TEM compression test showing that dislocation slip is responsible for the plastic deformation of an Mg single-crystal pillar under c-axis compression. (A) Hexagonal unit cell showing the loading orientation. (B) Stress-strain curve. (C) Snapshots showing an increase in dislocation density during compression. The dark-field TEM observation is conducted under a two-beam condition. Credit: Science (2019). DOI: 10.1126/science.aaw2843last_img read more

Metro celebrates

first_imgSet up at the Patel Chowk Metro station, the touch screen information system comprises of a touch screen kiosk along with a 65-inch high definition monitor, where visitors will be able to watch informational films on various aspects related to the Metro.‘The idea behind this museum is to exhibit our work. We wanted to give out information and share new developments,’ said Anuj Dayal, DMRC executive director for corporate communications.He said that the idea for this museum surfaced six years back. Also Read – ‘Playing Jojo was emotionally exhausting’‘I had visited London, and after seeing the London Transport museum I thought we too should have one such museum dedicated to the Delhi metro,’ he explained.The museum which was opened to the public on 1 January 2009, has various display panels, photographs and exhibits that trace the genesis of the Delhi Metro.As part of the celebrations, three new souvenir items – room thermometer, stationary kit and an umbrella were added for sale at the museum’s souvenir counter. An inter-school quiz competition was also organised in which students from Kendriya Vidyalaya, Chhawla, DMRC’s children home at Tis Hazari and East Point School, Vasundhara Enclave participated.last_img read more

Integration of work in the journey of the life

first_imgComprising of forty paintings that showcase the artist’s voyage across forty years, the exhibition 40 Years, 40 Works by Niren Sen Gupta explores his spiritual journey, the aesthetic nuances he distilled over the years. The abstract figures and the colours radiating energies off the canvas talk of the artist’s spiritual journey integrated into his work. He finds ready inspiration in the wisdom of the Ramakrishna Mission, in the monks he portrays in saffron robes, symbolizing the spirit of sacrifice. He uses symbolism in elements like the lotus; the auspicious banana tree and the usage of bright colours which help enforce the underlined message that there is hope for all mankind in a sublime and subtle manner. Also Read – ‘Playing Jojo was emotionally exhausting’Born in Bengal in 1940, Gupta imbibed the love, affection and the artistic bend of mind from his mother. Her lasting imprints can be seen in the way he portrays women in his works. He has participated in various group shows in India and abroad. He has been celebrated nationally through coveted awards like AIFACS Award, Maha Kaushal Award and Bangladesh National award. A senior artist-cum-art-educator Sengupta retired as the principal of College of Art, Delhi. He created his own brand, focusing mostly on Buddhist legends. The Prince or The Princess became the symbols of his work. Imbued with a sculptural style, which may even be termed as ‘Cubism’ (a geometrical approach to both figures and objects) Sengupta chissels his faces to show their various aspects and features. Even the rest of the picture space is filled with geometrically oriented objects (clothes and limbs too get the scene treatment). Colours, generally in a contrasting mode, are used as separating hues that define the form, finally. Things spiritual are the realm in which the artist delves with ease. However, he is prolific in his output and has experimented with various colour orientations. Of late, he has been touching upon themes that do not depend on the historic persona for their impact. Work like The Spiritual Journey features only a religious figure while retaining an spiritual environment.last_img read more

Soon fouryear integrated BEd course likely

first_imgKolkata: West Bengal University of Teachers’ Training Education Planning and Administration (WBUTTEP&A) is planning to introduce a 4 year integrated course on BA and BEd and BSc and BEd from the academic year 2018, that begins from July.The university, popularly known as BEd University, is working on a war footing to finalise the syllabus and other necessary parameters for commencement of the integrated course.It may be mentioned that till date, students have to pursue three year degree or pass courses in BA and BSc and then do a two year BEd course for taking up teaching in schools. Also Read – Heavy rain hits traffic, flightsThe integrated course will be of 4 years duration and will save a year for the students. Moreover, once a student seeks admission in an institution for BA or BSc now, he/she can do BEd from the same place.It is often found that students find it difficult to get admitted to BEd colleges after completing their degree course, due to the paucity of the number of seats in government and government-aided BEd colleges.”We feel this course will surely give a new dimension to those who want to take up teaching as a career option,” Soma Bandyopadhyay, vice-chancellor of WBUTTEP&A said. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe university will introduce the integrated course in phases in the different BEd colleges. “More than 10 colleges have written to us, stating that they have the infrastructure in place for starting this course,” a senior university official said.It has been learnt that WBUTTEP&A presently has as many as 413 colleges, including private BEd colleges under its aegis. The university that had started functioning on January 2015 with the initiative of the Mamata Banerjee government, has ushered in a uniform curriculum at all the BEd institutions and has contributed in reducing the fake or unaffiliated BEd colleges in the state.”BEd colleges in five districts – East and West Burdwan, Purulia, Bankura, and Birbhum are yet to come under WBUTTEP&A umbrella and we are working towards this,” the official said.last_img read more

CPM vote bank plummets to near nonexistence in Paschim Burdwan

first_imgKolkata: At a time when CPI-M is holding its Party Conference in Hyderabad to determine the future course of action, the party’s erosion of vote bank has hit rock bottom in Paschim Burdwan – once a stronghold of the party.Burdwan, then an undivided district, was a stronghold of CPI-M for decades. The Burdwan lobby used to control the party in Kolkata. There were great leaders from Burdwan, which included Benoy Chowdhury, Hare Krishna Konar, Rabin Sen, Mansoor Habibullah and Meheboob Zahedi. Also Read – Heavy rain hits traffic, flightsNow, the top leaders of the party from Burdwan are Madan Ghosh, Nirupam Sen, Mrinal Banerjee, Jiban Roy and Bansagopal Chowdhury among others. After bifurcation of the district, agrarian Burdwan falls under Purba Burdwan, while industrial Burdwan, which includes Asansol, Durgapur, Ranigunj and Andal, are parts of Paschim Burdwan.In Gram Panchayat, there are 833 seats. For these, CPI-M has fielded 337 candidates, with Congress fielding 26 candidates. CPI, which is a Left Front constituent, has fielded 20 candidates. Trinamool Congress has nominated 971 candidates, while BJP has nominated 253 candidates. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedIn Panchayat Samity, there are 161 seats. CPI-M and Congress have nominated 77 and 8 candidates respectively. BJP has fielded 56 candidates, while Trinamool Congress has fielded 196 candidates.In Zilla Parishad, there are 17 seats. CPI-M and Congress have fielded 15 and 6 candidates respectively. BJP and Trinamool Congress have nominated 19 and 17 candidates respectively.Political experts feel that the indifference of party leaders has failed to stop erosion of the mass base in Burdwan district. Congress has virtually become non-existent, with the party fielding 26 candidates in the 833 member Gram Panchayat, 8 candidates in the 161 member Panchayat Samity and only 6 candidates in the 17 member Zilla Parishad.CPI-M could not fill up even half of the Gram Panchayat and Panchayat Samity seats.There is a mass exodus from CPI-M to BJP. In industrial Burdwan, BJP has consolidated its base over the years. Though Trinamool had lost both the Durgapur seats in the 2016 Assembly election, CPI-M had failed to use the situation in its favour and now, BJP has developed its contacts in the grassroot level.last_img read more

Man arrested with explosives

first_imgHours before visit of US President Barack Obama, the Ghaziabad police have arrested a person carrying explosives at the Delhi-Ghaziabad border on Sunday. Police said that a huge quantity of explosives were recovered from his car. The explosives were illegal and he was trying to escape with them before he was apprehended. The police, however, have claimed to investigate the matter but have denied any link with the US President’s visit.The police were informed about the presence of few suspected elements along the border region. Suspecting foul-play ahead of the high-profile visit, security along border areas had been enhanced. Also Read – Company director arrested for swindling Rs 345 croreAt around 11:30 pm at Sangam Vihar under the jurisdiction of Loni police station, a Maruti 800 car was spotted in the area. When the police intercepted the vehicle, Jahiruddin, the occupant of the car, attempted to escape but was forced to stop. During the search of the vehicle, as many as 78 packets of explosives were found following which arrests were made.The police claimed that during the interrogation, Jahiruddin said that he was transporting the explosives to Farrukh Nagar, an area known for factories of local crackers. The cops, however, failed to explain why such a large quantity of explosives were being carried to the border area ahead of the US President’s visit. “We have arrested the suspected person and are investigating the matter. Although there is no connection with the visit of the US President, we are investigating the matter with utmost urgency,” said an official investigating the matter.last_img read more

Man held with pistol in Metro

first_imgA 25-year-old man was arrested for allegedly carrying a country-made pistol in the Delhi Metro here, an official said on Sunday. According to officials, the incident occurred on Saturday around 9:15 pm at the Peeragarhi Metro station when security officials of Central Industrial Security Force (CISF) detected a pistol in the baggage of a passenger. “The 25-year-old passenger, identified as Delhi resident Munna Pandey, was handed over to Delhi police. Pandey could not give a satisfactory reply as to why was the fire arm present in his baggage. Carrying of arms and ammunition in the Delhi Metro is prohibited and prosecutable under law,” a senior officer said.The Delhi Police later arrested Pandey and seized the weapon, the officer said.last_img