Journal information: Physical Review Letters © 2016 Phys.org Now researchers have filmed the first videos of the tiny (less than 100 nm) levitation space between the hot surface and the impacting liquid droplet, in this case not of water but ethanol and fluorinated heptane. The videos allow the researchers to directly observe, for the first time, how the shape of the droplet base changes as the surface temperature approaches the dynamic Leidenfrost temperature. This temperature varies depending on the type of liquid and increases with the impact velocity of the droplet.The researchers, Minori Shirota, et al., from the Physics of Fluids group at University of Twente, have published a paper on their investigation of the dynamic Leidenfrost effect in a recent issue of Physical Review Letters.To film the levitation space, the researchers used a technique called total internal reflection (TIR) imaging. By reflecting a laser beam off mirrors and into a prism at a particular angle, the researchers could transmit the resulting laser light through the droplets. This procedure creates grayscale images of dark wet droplets that visibly stand out against the lighter dry area, allowing the researchers to see where the droplet comes in contact with the surface, if at all. PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen Play An ethanol droplet impacts on a sapphire substrate at 150 °C. In the lower image, the top half shows the TIR image in original grayscale, while the lower half shows the calculated color height. The red color corresponds to a very low height, meaning that most of the droplet is in contact with the surface. Credit: Shirota, et al. ©2016 American Physical Society One of the most useful pieces of information obtained from the imaging is that the shape of the droplet base is not flat, as sometimes assumed, but ring-shaped. The scientists describe it as a “dimple and neck structure” in contrast to the previous “pancake model” that describes a flat bottom. The pancake model cannot accurately describe observations, and its incorrect assumption of a flat droplet bottom may explain why. “Drop impact on a superheated surface is of key importance in various applications,” coauthor Chao Sun, Physics Professor at the University of Twente, told Phys.org. “A quantitative physical understanding of the phenomenon is, however, lacking. In this work, we show that the whole impact dynamics is determined by the dimple and neck formation beneath the droplet at the very beginning of the impacting process.”From the TIR images, the researchers could quantitatively define three different boiling regimes (contact, transition, and Leidenfrost) as the temperature increases at the various impact conditions. Previous research has loosely classified these three regimes based on somewhat superficial factors such as the number of tiny droplets ejected by the main droplet. Explore further Play An ethanol droplet impacts on a sapphire substrate at 180 °C. There are more blue colors than at 150 °C, indicating that parts of this droplet are higher above the surface. Credit: Shirota, et al. ©2016 American Physical Society Here, however, the TIR imaging allows the researchers to calculate values such as the incident angle and the spreading radius of the droplet in order to generate a clearer picture and a more precise definition of the regime boundaries and associated transition temperatures. The improved understanding of the Leidenfrost effect could have a variety of industrial applications. More information: Minori Shirota, Michiel A. J. van Limbeek, Chao Sun, Andrea Prosperetti, and Detlef Lohse, “Dynamic Leidenfrost Effect: Relevant Time and Length Scales.” Physical Review Letters. DOI: 10.1103/PhysRevLett.116.064501, Also at arXiv:1511.04974 [physics.flu-dyn] A 2-mm-diameter ethanol droplet impacts on a hot surface. The corresponding videos with TIR images showing the droplet height are below. Credit: Shirota, et al. ©2016 American Physical Society “Heat transfer from solid surfaces to impacting liquid droplets plays an important role in many industrial technologies such as power electronics cooling, spray cooling, engine performance, and pollutant emissions,” said coauthor Detlef Lohse, Physics Professor at the University of Twente.In the future, the researchers plan to use their observations of the dimple and neck structure to develop more accurate models of the dynamic Leidenfrost temperatures for various types of liquids. A heat-seeking slingshot: Liquid droplets show ability to cool extremely hot surfaces Play An ethanol droplet impacts on a sapphire substrate at 220 °C. The red half circle shows the area of the spreading droplet, and the lack of color indicates that the droplet is high above the surface (greater than 91 nm, the TIR cut-off height). Credit: Shirota, et al. ©2016 American Physical Society “We aim to quantitatively and theoretically understand the dynamic Leidenfrost temperature, and plan to investigate the effects of the surrounding pressure on this fascinating phenomenon,” said Sun and Lohse. 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. PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen (Phys.org)—There are many cool videos showing the Leidenfrost effect, which occurs when water droplets levitate and skid around on top of a very hot surface, rather than immediately evaporating like they do at temperatures that are not quite as hot. The effect occurs because the bottom of the droplet rapidly vaporizes as it approaches the hot surface, causing the droplet to levitate on top of its own vapor. PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen Citation: Scientists record first video of the 100-nm space under an impacting Leidenfrost droplet (2016, February 19) retrieved 18 August 2019 from https://phys.org/news/2016-02-scientists-video-nm-space-impacting.html
Yusuf mentions that in this series we are face to face with the third dimensional print making; the fiber cast of the form, the cast of the paper pulp, the shadow on the wall, the transparency of the gauze showing its warp and weft and the thread ends, all contribute varying elements of mass, surface and lines.Creating these pieces has a unique process; the artiste begins his work by drawing images on rice paper and pastes it on the acrylic. He then studies the form to negotiate its shadow. Finally, he evolves the forms from his sketches and drawings made on rice paper, of cast objects created with paper pulp and fiber glass. Also Read – ‘Playing Jojo was emotionally exhausting’The study of light on these objects and the shadow created thus are also integral to these drawings. Later these drawings on the rice paper are cut rendering them with a geometric edge to suit his creative impulse.The use of colours in his canvasses is minimal – black, white and mustard. The lines are in every imaginable form – linear, horizontal, squares or rectangles. Yusuf’s world of abstractions has come after years of experimenting with different modes, even figurative art. Talking about the line, his muse, Yusuf says, ‘The line is the most abstract element – it has no end or beginning. And basic elements don’t change. It is how one chooses to use it that then becomes paramount.’ Also Read – Leslie doing new comedy special with NetflixThe lines and the play of multiple surfaces and medium render a sculptural dimension to the print imprint works. Yusuf mentions ‘I started 10 years back while I was in charge of the print making studio; I was face to face with the conventions defining the practice of print making. With the availability of new materials and my exposure to the international scenario, I wanted to engage in a more active and responsive way of working.’When: 23 November onwardsWhere: IGNCA
BALURGHAT: Four of the family members including two women were killed and one seriously injured when the car they were travelling in hit the road divider after the driver lost control. The accident took place in Kanki under Chakulia police station in North Dinajpur on National Highway 31 on Friday. Police said the injured person was admitted to Kishanganj Medical College and Hospital in critical condition. The driver of the vehicle was also killed. Also Read – Heavy rain hits traffic, flightsEntire traffic system of NH 31 was disrupted for about one hour following the mishap.Police said the identity of the deceased is yet to be ascertained. According to police, the family members who hailed from Haryana was headed towards Assam to attend a function. One of the family members was driving the car. There was huge traffic jam before Dalkhola railway crossing when the car reached there. After the bottleneck got cleared, the driver accelerated to cover up the time that was wasted and reach Assam as per schedule. On reaching Kanki, one of the front tyres burst causing the accident. The vehicle hit the road divider killing four of the travelers including the driver on spot. The vehicle overturned.Police are trying to contact their counterpart in Haryana to know about the whereabouts of the deceased.
Of the estimated Rs 15,000 crore losses due to the recent devastating floods in Chennai, coastal Tamil Nadu and the neighbouring Puducherry, MSMEs bore the maximum brunt of about Rs 1,700 crore, says a report.On a most conservative side, MSME sector has lost nearly Rs 1,700 crore to the calamity in just two peak weeks of the flooding,” SMERA Ratings lead economist Karan Mehrishi said.This is a very conservative estimate and the actual financial losses in terms of lost opportunities and job losses could be much higher, he added. Also Read – Punjab & Sind Bank cuts MCLR by up to 20 basis pointsVarious analysts have pegged the overall loss to the industries in the region at over Rs 15,000 crore from the month-long floods which had even forced the airport and the railways to shut operations for nearly a week.City-based SMERA Ratings is a joint initiative of Sidbi and some state-run banks, and the private sector financial advisor Dun & Bradstreet Information Services India. He also said that this Rs 1,700 crore projected loss is only from the manufacturing side and if services are included, the damages could be much higher. Also Read – ‘The great gold bull market has begun’“The impact of the floods has serious ramifications on not only the local economy but also national economy as the Chennai metropolitan region’s manufacturing economy is worth Rs 1,51,800 crore or around 3 per cent of the national GDP, Mehrishi said.The loss figure has been arrived at after calculating the weekly loss in lost businesses for the micro and small industrial sector, which bore the brunt of the killer floods at nearly Rs 840 crore, he added. This makes the annual size of the Chennai metropolitan region’s MSME manufacturing GDP at around Rs 21,500 crore. According to SMERA analysis, seven major MSME categories of industry and industrial services in the region, were hit the most due to the floods. The leather sector bore the maximum losses with estimated damages of over Rs 380 crore, followed by gold and jewellery sector at Rs 237 crore, auto components at Rs 105 crore, printing sector at Rs 37.50 crore, Mehrishi said. Story PageChennai floods wash out Rs 1700 crore of MSME businessThe next in line of losses is the plastics sector which is estimated to have lost Rs 35 crore, followed by IT related services at over Rs 33 crore, garments at Rs 10 crore and pharmaceuticals (ayurveda & siddha) at Rs 1.25 crore.There are an estimated 36,000 MSMEs registered in the Chennai region and the agency has analysed a sample size of nearly 20,000. Among the large contributors, auto components and related businesses contribute 28 per cent to the region’s economy. It can be recalled that a slew of automakers like BMW, Ford, Nissan, Renault, Royal Enfield, Hyundai, Ashok Leyland, among others, have given Chennai the moniker of Detroit of the East.IT and related services come second with a contribution of 17 per cent, gold about 8 per cent, leather at 6.4 per cent, printing at 4.2 per cent and garments at 3.27 per cent, respectively. On individual loss of the city’s citizens, the per capita loss stood at nearly Rs 2,530 in terms of potential income loss with every week foregone.
Kolkata: A middle-aged man, whose identity is yet to be confirmed by the police, was killed in a road accident on Jessore Road near Doltala in North 24-Parganas on Tuesday morning.The incident led to traffic congestion on the busy Jessore road. Police said that the victim was riding a motorcycle on his way to the airport when a speeding truck coming from the opposite direction knocked him down. Due to the intensity of the accident the victim fell at a distance. Also Read – Bose & Gandhi: More similar than apart, says Sugata BoseThough the victim was wearing a helmet it fell off from his head when he was hit by the truck. The person received critical head injuries on his head and also on other parts of his body. Local residents rushed to the spot immediately after the accident. The victim was taken to a nearby hospital where the doctors declared him brought dead. Onlookers gathered in the area, which led to traffic congestion. The vehicular movement resumed after the police removed the truck from the accident site almost 40 minutes after the accident. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataAfter being informed police reached the spot and dispersed the mob. The truck driver fled from the spot immediately after the accident leaving the vehicle at the accident site. An eyewitnesses told the police that the truck was moving at a high speed as a result of which the driver could not control it when the motor cycle came on its way. The driver applied a sudden emergency brake but failed to avert the collision. The incident triggered tension among the local residents as well. According to the hospital sources the victim died due to excessive bleeding. The police are trying to ascertain the identity of the victim. Police have started a detailed probe into the incident. They have seized the truck and examining if the vehicle had developed any technical problem. The motor cycle that the victim had been riding was also damaged in the accident. The police are conducting raids to nab the truck driver. In another incident, a bike rider was killed and the pillion was injured after the bike rammed in to a roadside wall on Zeerut Bridge at Alipore. Samrat Chakraborty (27) a resident of Chetla were riding his bike towards Babughat with a Light Goods Vehicle (LGV). Amit Mondal, the pillion rider, stated that a truck hit them and as a result Chakraborty almost got beheaded.
Kevin Missal was always on the lookout for an Indian super hero and when he did find one, he couldn’t resist the urge to tell the story of an ‘Avatar of Vishnu’ to the world.Kalamos Literary Services in association with “Jashn Events” celebrated the launch of “Dharmyoddha Kalki”, a Book on avatar of Vishnu by Kevin Missal’s at Oxford Book Store, Delhi. This book explores every individual’s responsibilities towards society.The book revolves around Kalki Hari, son of Vishnuyath and Sumati. Born in the quiet village of Shambala, Kalki has no idea about his heritage until he is pitted against tragedies and battles. Also Read – Add new books to your shelfWhisked into the province of Keekatpur, which is under the fist of Lord Kali, Kalki sees the ignominy of death trumping life all around him. He learns that he has been born to cleanse the world he lives in, for which he must journey to the North and learn the ways of Lord Vishnu’s Avatar; from an immortal who wields an axe. But trapped in the midst of betrayals, political intrigue and forces that seek to decimate him, will he be able to follow his destiny before the Kaliyug begins? Also Read – Over 2 hours screen time daily will make your kids impulsiveKevin Missal at the time of launch said, “I always wanted to create an Indian Hero. Since childhood I looked up to Percy Jackson, Pendragon, Harry Potter and I have never read about an Indian hero. So my journey starts from there, I began fleshing out a god who was not properly explored and I made a hero that young kids could look up to. So if someone asked me what Kalki is, I would say it’s about creating childhoods. I began researching about Kalki, who was created out of the Huna and shaka invasion, according to history. I researched for two years and completed the book in a month.”
Kolkata: People in the city and other districts of South Bengal who had been under a tremendous heat spell for the past few days heaved a sigh of relief after thunderstorms hit certain parts of the state resulting in a dip in temperature.The Regional Meteorological Centre in Alipore predicted rain and thundershowers in various South Bengal districts in the next 48 hours, particularly in the evening. Though during the day time, hot and humid conditions may prevail, added the weather office. The monsoon is expected to enter the state early next month. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataThundershowers along with gusty winds swept through the city and some South Bengal districts on Saturday evening. Though, they did not last for too long but they brought the much needed relief for the city dwellers from sultry weather. The MeT office also forecast that districts like Birbhum, Nadia, Bankura, Malda will witness moderate rainfall along with gusty winds in the next two days. A hailstorm is expected to hit some parts of South Bengal as well. Thundershowers may also lash other districts like North 24-Parganas, Hooghly, Howrah and adjoining parts of the city on late Monday night. Also Read – Lightning kills 8, injures 16 in stateAccording to a weather official, the mercury will slide down by a few notches immediately after the thundershowers but the discomfort level may not be reduced as the humidity is still expected to be on the higher side. Interestingly, the temperature may be slightly higher during the night in comparison to the temperature that is normally found during this time of the year. The MeT office also predicts that North Bengal districts will receive heavy thundershowers in the next 48 hours. Hailstorms is also likely to hit several districts in North Bengal as a result of which tea gardens may face damages. There will be occasional downpour and gusty winds in South Bengal in the next two days. It may be mentioned here that entire South Bengal continued to burn under the scorching sun for the past one week resulting in discomfort for the city dwellers. The temperature touched 42-43 degree in the Western districts like Bankura, Purulia and West Midnapore. The average maximum temperature in the region remained high throughout the day in the past couple of days due to the inflow of northwesterly winds to Bengal from the neighbouring states.
Gurugram: As part of its CSR initiative of Candor TechSpace, the leading provider of IT/ITES office spaces has adopted a Government Primary School in Tikri, Gurugram (Haryana) to develop its overall infrastructure and educational capabilities after signing an MOU with the government. The inauguration of the Phase-I Infrastructure development of the School took place on January 16, 2019 by Mr. Ravinder Yadav, Joint Commissioner-IV, Municipal Corporation of Gurugram- Haryana in the presence of Mr. Kuldeep Yadav – Councillor Ward-29-MCG and Mrs. Premlata Yadav- DEEO, Gurugram. The developmental work scheduled tobe carried out in phases. Also Read – Add new books to your shelf In phase 1, Candor TechSpace is working towards to uplift the hygienic infrastructure of the school. We have already built new toilet block that comprise 3-4 separate toilets for both genders and one with a wheelchair ramp for differently abled students, a drinking water station (RO + water cooler), a utensil washing area and a proper drainage system which is covered and connected to the main sewage. Built as per the ‘A’ specifications, we have appointed a housekeeping company to maintain and manage the facility. Also Read – Over 2 hours screen time daily will make your kids impulsive Sharing his insight on the initiative, Spokesperson of Candor TechSpace, said, “At Candor, we believe quality education is a fundamental right of children, regardless of their background or financial state. Unfortunately, there exists a huge gap between the quality of private schools and state-run public schools. We wanted to bridge this gap to some extent through this initiative. While the government is making relentless efforts, it’s also the responsibility of large corporate entities to play their part.” He further added, “We have just finished building the toilet blocks and plastering the school’s boundary wall. We have also roped in award winner Akshita &team from Rocks Artist for decorating the classrooms with meaningful wall arts that spread awareness about issues such as water scarcity, environmental sustainability and hazards of pollution. At present, we are looking to develop the landscape; such as equipping the school play area with swings and play equipment’s” he added. In the second phase of the project, Candor TechSpace looks to upgrade the classrooms with better facilities and a resource center in each class. The latest initiative of Candor further reaffirms its commitment towards the society.