“It is projected that the next generation of computer chips will produce localized heat flux over 10 MW/m2, with the total power exceeding 300 W. No existing low-cost cooling device can effectively manage the heat produced at this level,” asserts the Letter. The study will accelerate the development of next generation of cooling devices that incorporate nanofluids for ultrahigh-heat-flux electronic systems.The results of the experiment show that when an oscillating heat pipe (OHP) is charged with a nanofluid, the ability of the OHP to transport heat increases. As this experiment illustrates, finding more efficient cooling for the next generation of computer chips, microchips, and electronic devices is under way. As society desires its gadgets to shrink ever smaller resulting in high power density, teams that work to develop the technology will find themselves in high demand. “There are lots of applications that come from this experiment,” says Ma. “We really need to develop this further.”While neither the study of nanofluids nor the study of OHPs is anything new, combining the unique features of each is an innovative approach. “Here we use a nanofluid and an oscillating motion. The oscillating motions make the nanoparticles suspend in the base liquid. This is unique.” says Ma. “No cooling device has been made using a nanofluid-charged OHP, but the development of such a device is now a few steps closer, and with it the enabling ability to take our technology even farther than it has already gone.”The unique characteristics of both nanofluids and OHPs contribute to the fitness of such devices for cooling functions. Traditional liquids have much lower thermal conductivities than nanofluids. Additionally, nanofluids have strong temerpature-dependent thermal conductivity, as well as showing a non-linear relationship between thermal conductivity and concentration. These particular features, which belong to fluids that exist on the nanoscale, make them high performance conductors with an increase in critical heat flux.Oscillating heat pipes have their own set of unique features. First of all, an OHP is known as an “active” cooling device. It takes intense heat from a high-power device and turns it into kinetic energy of fluids. Additionally, with an OHP, liquid flow and vapor flow move in the same direction, so neither phase interferes with the other. Because the flow in an OHP is one that oscillates from a thermally driven flow, there are some blank surfaces that appear along the pipe. This allows for enhanced evaporating and condensing heat transfer. So, while the OHP already has good heat transporting ability, the addition of a nanofluid can enhance the ability of the OHP significantly. In this particular experiment, the nanofluids used contained diamond nanoparticles. The diamond particles were introduced into high performance liquid chromatography (HPLC) water. HPLC water is water that is specially purified and that has a low organic carbon content. Even though diamond particles might settle in liquid without motion, the movement of an OHP keeps those particles from settling, allowing them to remain suspended.While the experiment shows that the nanofluid-charged OHP has increased efficiency, the ‘why’ behind the fact has yet to be discovered. “We know some of the reasons,” explains Ma, “but not all. We are trying to find the reason for the higher efficiency transfer. We’re not entirely sure why the efficiency increases so much after we add the nanoparticles.”The results from this experiment are encouraging to those who are studying ways to effectively reduce the size of electronics while increasing their output, as it points to a technique that can used for effective cooling. As the letter puts it: “This study on a nanofluid OHP will advance the state of the art in nanofluid applications…”By Miranda Marquit, Copyright 2006 PhysOrg.com “This is the next generation of cooling devices,” Dr. Hongbin Ma tells PhysOrg.com. With a group of students at the University of Missouri-Columbia, and colleagues at Argonne National Laboratory and Intel Corporation, Ma presents the findings of a unique cooling device that makes use of an Oscillating Heat Pipe (OHP) and nanofluids. The findings, published online at Applied Physics Letters on April 5th, present a breakthrough that will provide a way for cooling technology to keep pace with developments in electronic technology. Citation: Future Computer Chips Could Be Cooled With Nanofluid (2006, April 20) retrieved 18 August 2019 from https://phys.org/news/2006-04-future-chips-cooled-nanofluid.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.
Most computers today store memory electronically, by maintaining a certain voltage. In contrast, a new kind of memory that stores data thermally, by maintaining temperature, is being investigated by researchers Lei Wang of the National University of Singapore and the Renmin University of China, and Baowen Li of the National University of Singapore and the NUS Graduate School for Integrative Sciences and Engineering. Citation: Scientists Propose Thermal Memory to Store Data (2009, January 7) retrieved 18 August 2019 from https://phys.org/news/2009-01-scientists-thermal-memory.html Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. In recent years, thermal research has improved scientists’ understanding of heat conduction on a molecular level. Scientists have created theoretical models of some thermal devices, including a thermal transistor and logic gate, both by Wang and Li in 2006 and 2007, respectively. This kind of work has opened the doors to the new subject of “phononics” – the science and engineering of processing information with heat. In the current study, Wang and Li take the field of phononics one step further and show the feasibility of a thermal memory that can store data with heat. The scientists predict that such a heat memory could be experimentally realized in the foreseeable future with rapidly advancing nanotechnology. Their work is published in a recent issue of Physical Review Letters.As Wang and Li explain, any thermally insulated system might be a candidate for thermal memory since it maintains its temperature (data) for a long time. Still, any system will face the challenge of unavoidable perturbation when the temperature is measured (when the data is read). Due to energy exchange between the thermometer and the system, the system won’t be able to naturally recover its original temperature after the data reading. To solve this problem, the researchers suggest using a thermal circuit capable of producing two steady states, which is connected to a power supply from an external heat bath.Wang and Li’s thermal memory consists of a single particle sandwiched between two lattice segments, each consisting of about 50 atoms. These left and right segments are connected to heat baths at different fixed temperatures, and the central particle is connected to a control heat bath that can be set to “on” or “off.” The particle’s chosen state can remain unchanged for a long time even after the heat bath is removed. The particle and the segments are also weakly coupled together by harmonic springs. This memory system, the researchers explain, can perform a complete write-read process. The “writer” is made of a lattice of about 10 particles, connected to the central particle by a linear spring. The other end of the writer is connected to a heat bath. Depending on the supply from the heat bath, the writer can either cool the particle to the off state or heat it to the on state. To read the data, a thermometer (made of the same lattice as the writer) is connected to the central particle. Unlike the writer, the reader is not connected to a heat bath, but is set to a temperature between the on and off states. If the particle is in the on (hot) state, the reader will heat up; if the particle is off (cool), the reader cools down. Of course, the particle’s temperature will also change when exposed to the medium-temperature reader. But the heat baths connected to the left and right segments will either absorb the particle’s excess heat or warm the particle, so that the particle recovers its original temperature (and state) in either case.The researchers calculated that, when the writer is removed, the system can maintain its state for a relatively long time, although an ideal thermal memory is impossible due to thermal fluctuations. However, by refreshing the data (similar to how voltage data is regularly refreshed in dynamic random access memory [DRAM]), thermal memory can achieve a lifetime long enough for practical applications. The scientists also noted that the lifetime can be extended further by combining identical memories together.By theoretically demonstrating the possibility of a thermal memory that is self-recoverable after being read by a thermometer, Wang and Li hope that computers will one day reap the benefits of thermal technology.More information: Wang, Lei and Li, Baowen. “Thermal Memory: A Storage of Phononic Information.” Physical Review Letters 101, 267203 (2008).© 2009 PhysOrg.com Controlling heat and particle currents in nanodevices by quantum observation
© 2012 Phys.org The AU is at its root a measure of the distance between the Earth and the sun; which was first calculated by the famous astronomer Giovanni Cassini who noted the position of Mars while standing in Paris and compared it to its angle in the sky when viewed from a site in South America at the same moment in time. Using parallax he was able to come up with a very close estimate of just how far the Earth was from Mars, and then the Earth from the sun, which he said should be about 140 million kilometers. That eerily accurate figure came to be used throughout astronomy as a standard for describing distances in the visible solar system. To make it more accurate, the calculation was changed in 1976 to include a tie to the sun’s mass, which for newcomers to the field only made things more difficult to understand. It also didn’t take into account the fact that the sun is gradually shrinking.Subsequent new developments in science and technology have led to much more precise ways to measure the distance between solar objects, which served to make using the old calculation even more obsolete. The only reason it’s lingered as long as it has, astronomers say, is because everyone was used to it and thought changing things might be too disruptive.That line of thinking apparently gave away to common sense at the latest meeting of the IAU, as members voted to make the AU an exact 149,597,870,700 meters, which is the average mean distance between the Earth and sun when viewed from the Earth. This last point is important because the old calculation violated Einstein’s Theory of Relativity in that using it should have given different answers depending on where the measurement was taken, i.e. from different objects in the solar system.Most in the field seem to be relieved to finally have the AU changed to a constant, believing it will help make their work more accurate and because it will, of course, require a lot less explaining to those new to astronomy. Explore further
(Phys.org)—A trio of researchers working in Germany has discovered that male spiders do indeed have nerves in their genitalia, overturning prior research that has suggested otherwise. In their paper published in The Royal Society Biology Letters, Elisabeth Lipke, Jörg Hammel and Peter Michalik describe the various techniques they used to discover nerves in the arachnid palpal organ and their ideas on what purpose they serve. Citation: Nerves found to exist in male spider genitalia (2015, July 8) retrieved 18 August 2019 from https://phys.org/news/2015-07-nerves-male-spider-genitalia.html Explore further More information: First evidence of neurons in the male copulatory organ of a spider (Arachnida, Araneae) The Royal Society Biology Letters, Published 8 July 2015.DOI: 10.1098/rsbl.2015.0465AbstractSpider males have evolved a remarkable way of transferring sperm by using a modified part of their pedipalps, the so-called palpal organ. The palpal organ is ontogenetically derived from tarsal claws; however, no nerves, sensory organs or muscles have been detected in the palpal bulb so far, suggesting that the spider male copulatory organ is numb and sensorily blind. Here, we document the presence of neurons and a nerve inside the male palpal organ of a spider for the first time. Several neurons that are located in the embolus are attached to the surrounding cuticle where stresses and strains lead to a deformation (stretching) of the palpal cuticle on a local scale, suggesting a putative proprioreceptive function. Consequently, the male copulatory organ of this species is not just a numb structure but likely able to directly perceive sensory input during sperm transfer. In addition, we identified two glands in the palpal organ, one of which is located in the embolus (embolus gland). The embolus gland appears to be directly innervated, which could allow for rapid modulation of secretory activity. Thus, we hypothesize that the transferred seminal fluid can be modulated to influence female processes. Cutting a bugs’ penis shorter found to reduce reproduction chances Araneus diadematus. Credit: André Karwath/Wikipedia © 2015 Phys.org For many years scientists have believed that the palpal organ in male spiders—the organ responsible for delivering sperm to the female spider—had no nerves in it. That would mean that the male would not be able to feel anything during intercourse, which some observers have likened to attempting sex with a fingernail in the dark. It appears prior researchers did not look hard enough, however, because the trio working on this new effort report that they have found evidence of nerves in the palpal organ.To make their discovery, the team first cut up several of the organs (from a male Tasmanian cave spider) into extremely thin slices. They then looked at the samples using three different types of microscopes, one of which was a transmission electron microscope—and that allowed them to spot a tiny nerve. More work revealed two clusters of nerves in the bulb. They also spotted two previously unknown glands also in the palpal bulb which appeared to be connected the nerves they found. Using data from the microscopes, the team built a 3D model of the palpal showing where the nerves are in the organ.The researchers suggest that the nerves in the palpal bulb might serve to allow the male spider to feel stress on the organ during copulation, helping to improve placement and thus chances of successful fertilization. It is also possible, they note, that the nerves help with guiding the palpal to the female sex organ. They believe that it is unlikely that such nerves exist only in the species they studied, which means other spiders likely have them too. More research will be needed to find out. The team also plans to study the nerves they found to see if they can determine their true purpose. 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.
Theatre veteran, actor and director Nadira Zaheer Babbar hits the capital stage with her entourage to recreate the era of 1950s. Actor Anup Soni and Juhi Babbar Soni would play the leading roles in the three plays set for the Capital’s stage from 18 to 20 July at Shri Ram Centre. Delve in the charms of 50s with these three plays, namely, Salaam 1950s ke naam, Begum Jaan and Yeh hai Mumbai Meri Jaan. Written and directed by Nadira Babbar, Salaam.. 1950s ke naam Also Read – ‘Playing Jojo was emotionally exhausting’ will be staged on 18 July, to portrays Nadira’s undying love and immense admiration for the cinema of 1950s. Interlaced with ingredients such as star-crossed lovers, revengeful thakurs and kabeelawalas (tribesmen), love triangles, family ties, sacrifice, shrewd and conniving villains and vamps, friends with hearts of gold, loyal munims, comedian’s love tracks, long-lost over dues and lovers separated by fate, dramatic reversals in love and convenient coincidences, this play is a new tribute to the golden era of 1950s. Also Read – Leslie doing new comedy special with NetflixBegum Jaan, set for 19 July, is the story of a legendary classical singer of yesteryears. The play revolves around the interpersonal relationship amongst the three characters: the extremely witty old lady Begum Jaan, her grand daughter Zarina and Sanjay Pande, a journalist who comes into their lives.The play is a reflection of the changing face of India, from pre-independence days to its current state, through Begum Jaan’s narration of various events in her life. The last play in the series, Yeh hai Mumbai Meri Jaan will be staged on 20 July. It elaborates on the whimsical life in the tinsel town where every day hordes of people come flocking to the city achieve their dreams in life. Head over and witness the on-stage revival of 1950s.
Tribal artisans from all over the country will present craft items, handloom products, dry flowers, cane and bamboo products, tribal jewellery, dhokra craft, tribal weaves and embroidery, tribal paintings and a lot more.The main objective of organising Adishilp is to give tribal artisans an opportunity to showcase and sell their traditional arts and crafts directly to the customers and get feedback which would provide valuable inputs. It provides them a platform for direct interface with art and craft lovers, share their talent with the urban elite and know the customers’ tastes and preferences to change their product designs and creations.WHEN: OngoingWHERE: Dilli Haat
Kolkata: The state government has set up a committee to celebrate the 150th birth anniversary of Mahatma Gandhi.The committee was formed on April 18. Chief Minister Mamata Banerjee is the chairperson of the 46-member committee. The state government has taken a set of decisions in the first meeting of the committee, that was held on Monday.Members of the committee, including MPs Sudip Banerjee and Subrata Bakshi, minister of state for Health Chandrima Bhattacharya and Chief Secretary Malay De were present in the meeting, headed by the Chief Minister. Also Read – Heavy rain hits traffic, flightsVice-chancellors of Calcutta University, Rabindra Bharati University, Presidency University and Jadavpur University were also present in the meeting. There would be a permanent chair in the name of Gandhiji in Calcutta University. The university would take the final decision in this connection soon.De said: “There is a Gandhi Bhavan at Beliaghata. Though at present it is maintained by the state Public Works Department (PWD), steps have been taken to completely take over the structure. Proper renovation of the structure will be undertaken, maintaining the heritage of the building. It will be done following discussions among committee members.” Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedHe further said: “This year on October 2, a programme will be organised at Gandhi Bhavan.” The state government will plan the detailed programme accordingly. Some decisions regarding the celebration, have been taken. Based on the philosophy of Gandhiji, elocution and essay competitions will be held in schools, colleges and other educational institutions. The step has been taken to spread the messages of Gandhiji among people, the youth in particular. A booklet named as “Father of the Nation”, containing speeches of Gandhiji on different issues including communal harmony, national integration and patriotism, will be published on his birthday on October 2.”Since East Midnapore has a rich history of the freedom movement, the state government is looking into the formalities to name the university there on Gandhiji,” he said, adding that at the same time, the universities in the state will also organise programmes to celebrate the 150th birth anniversary of Mahatma Gandhi.Presidency University has a centre on Gandhian awareness, where they will organise seminars and symposiums in this regard.