Solving Teapot Effect

first_img Citation: Solving Teapot Effect (2009, November 2) retrieved 18 August 2019 from https://phys.org/news/2009-11-teapot-effect.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. Previous research on the teapot effect has found that at higher flow rates the layer of fluid closest to the surface of the teapot spout becomes detached from it and the fluid flows smoothly. At low flow rates there is flow separation in which the boundary layer reattaches to the surface instead of flowing over it, causing the flow to stop and start; in other words to dribble. A number of factors are known to affect how much the teapot dribbles, such as the diameter of the spout, the teapot material, and speed of flow, but until now no one has come up with a scientific solution.Fluid dynamics experts C. Duez, C. Ybert, C. Clanet, and L. Bocquet, from the University of Lyon have solved the problem by identifying the fundamental cause of dribbling: a “hydro-capillary” effect that keeps the liquid in contact with the surface as it leaves the spout. The other factors — “wettability” of the teapot material, velocity of the flow, and curvature of the lip — determine the strength of this effect.The authors suggest that one way to avoid dribbling is to make the lip of the spout as thin as possible (as in metal teapots, which rarely dribble), while the ultimate way to instantly stop dribbling and end the teapot effect for good is to use a thin, sharp-ended spout and coat the lip with one of the latest super-hydrophobic materials. These materials strongly repel water and prevent the tea from clinging to the teapot material, which adds weight to the old idea that smearing butter on the spout stops dribbling.Duez and his colleagues also suggest that some super-hydrophobic materials can be controlled electronically, and while it is hard to see why anyone would want a teapot with a dribble switch, there may be applications in controlling fluid flow in microfluidic devices.The research paper is published online in arXiv.org.More information: Beating the teapot effect, C. Duez, C. Ybert, C. Clanet, L. Bocquet, arXiv:0910.3306© 2009 PhysOrg.com Innovative spout will increase maple production up to 90 percent Explore further Beating the teapot effect with a superhydrophobic coating. Top: water flow under the spout of an (hydrophilic) teapot, exhibiting a bending of the streamlines (a), and drip-ping as the water flow decreases (a’). Bottom: In contrast, a teapot with a spout coated by a superhydrophobic coating (here black soot) fully avoids dripping (b and b’). Image: FIG 1. from arXiv:0910.3306. (PhysOrg.com) — A team of scientists from France have worked out why teapots dribble at low flow rates, and how to stop them. The effect is called the “teapot effect”, and solving it could finally put an end to tea stains from dribbling teapots.last_img read more

Sony patent seeks to correct autostereoscopic blur

first_img © 2012 Phys.Org Image: USPTO, number 0910660.0 What this means is that Sony is planning to resolve the disadvantages of no-glasses 3-D viewing in the home. Critics have often noted blurring and other compromised effects that make the 3-D viewing experience less than desired just because the viewer is not in the best position. The success of autostereoscopic (glasses-free) 3-D has depended highly on the viewer’s angle and distance from the screen. With Sony’s 3-D viewing concept, the application would be able to detect a user’s distance from the screen and adjust the separation of images accordingly.Sony points out past technology limitations of 3-D viewing with no glasses in its patent: “3-D content is recorded using a stereoscopic camera having a fixed arrangement of lenses that presuppose a corresponding fixed viewing position.” The problem, says Sony, is that the effect of being in the wrong place for viewing is discouraging. According to the patent, “the reproduced image can feel unnatural and in extreme cases may lead to headaches or nausea.” Sony says one particular weakness is under- or over-exaggeration of depth, depending on how near or far the user is from the screen.The patent is for both an image-processing method and an entertainment system for the image display. The patent says that Sony’s technology involves shifting image elements in at least one of the left-eye and right-eye images to change the size of displacements, as a function of existing displacements, and the point of intersection of lines of sight between the corresponding image elements and the viewer. The separation in depth between different image elements is substantially the same as it would have been if the user had been viewing the video at the ideal distance.Sony’s patent does not represent the first attempt of a company seeking to evolve non-glasses 3-D viewing. Cebit in 2010 in Hanover, Germany, is a case in point. Technology companies at Cebit created a stir showing efforts toward a new breed of displays. Sunny Ocean Studios had a panel fitted to a standard display, sending out a stereoscopic image to 64 positions around the screen. That meant you would be able to “run around” and see a nice 3D display, said Armin Grasnick of Sunny Ocean, at the time. Another company, SeeFront, showed a display moving with the viewer’s eyes, with the viewer always seeing the 3-D image. Eye-tracking has been an essential component of its glasses-free 3-D display technology, according to SeeFront. Explore further Citation: Sony patent seeks to correct autostereoscopic blur (2012, May 13) retrieved 18 August 2019 from https://phys.org/news/2012-05-sony-patent-autostereoscopic-blur.htmlcenter_img (Phys.org) — Sony has filed a patent with the U.S. Patent & Trademark Office for a glasses-free 3-D display that will adjust the picture so that the user gets an optimal view no matter how far or close to the screen. In its application, “Stereoscopic Image Processing Method and Apparatus,” Sony defined its patent intent: “A stereoscopic image processing method for a stereoscopic image pair forming a 3-D image comprises the steps of evaluating whether the distance of a user is closer or further than a preferred distance from a 3-D image display upon which the stereoscopic image pair is to be displayed, and if the evaluation indicates that the user is further than the preferred distance from the 3-D image display, adjusting the respective displacements between corresponding image elements in the stereoscopic image pair, thereby changing the stereoscopic parallax in the 3-D image.” Apple patents an inexpensive 3-D projection system 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

Climate change may be making bearded dragons less intelligent

first_img 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)—A team of researchers affiliated with the University of Lincoln in the U.K. has found evidence suggesting that as the planet heats up due to global warming, the bearded dragon may become less intelligent. In their paper published in the journal Royal Society Open Science, the group describes exposing incubating bearded dragons to warmer than normal air temperatures and then testing their intelligence. Play A bearded dragon takes on a new task after watching video footage of another bearded dragon, and successfully opens the door to receive a food reward. Credit: University of Lincoln Bearded dragons change color on different body parts for social signals and temperature regulation Explore further Citation: Climate change may be making bearded dragons less intelligent (2017, November 22) retrieved 18 August 2019 from https://phys.org/news/2017-11-climate-bearded-dragons-intelligent.html More information: Harry Siviter et al. Incubation environment impacts the social cognition of adult lizards, Royal Society Open Science (2017). DOI: 10.1098/rsos.170742AbstractRecent work exploring the relationship between early environmental conditions and cognition has shown that incubation environment can influence both brain anatomy and performance in simple operant tasks in young lizards. It is currently unknown how it impacts other, potentially more sophisticated, cognitive processes. Social-cognitive abilities, such as gaze following and social learning, are thought to be highly adaptive as they provide a short-cut to acquiring new information. Here, we investigated whether egg incubation temperature influenced two aspects of social cognition, gaze following and social learning in adult reptiles (Pogona vitticeps). Incubation temperature did not influence the gaze following ability of the bearded dragons; however, lizards incubated at colder temperatures were quicker at learning a social task and faster at completing that task. These results are the first to show that egg incubation temperature influences the social cognitive abilities of an oviparous reptile species and that it does so differentially depending on the task. Further, the results show that the effect of incubation environment was not ephemeral but lasted long into adulthood. It could thus have potential long-term effects on fitness.Press releasecenter_img Journal information: Royal Society Open Science Central bearded dragon. Credit: Greg Hume/Wikipedia/CC BY-SA 3.0 © 2017 Phys.org Over the past several years, scientists have been finding that creatures great and small are smarter than commonly assumed. This is the case for bearded dragons, the people-friendly reptile from Australia. Some studies have shown, for example, that they are able to note the behavior of their peers and then copy it if it offers a reward. Such behavior offers a means for testing the intelligence of individuals among a group.To find out what impact rising temperatures might have on the bearded dragon, the researchers incubated 13 eggs, seven in a warmer than normal 30 degrees Celsius nest and six at the normal 27 degrees C. After they hatched and grew older, the researchers tested the intelligence of all the lizards by exposing them to a video showing a bearded dragon opening a sliding door and then testing them to see if they could or would imitate the behavior for a reward—prior research showed that opening a screen door is something the lizards can only learn if they see another lizard do it first.The researchers report that fewer of the lizards that incubated in the warmer pens were able to mimic the lizard on the video than those that had incubated at normal temperatures—and those that did succeed did so at a much slower pace. This, the researchers suggest, indicates that as the planet warms, animals across the globe will be impacted in some unexpected ways. For the bearded dragon, it could spell serious trouble if they become less intelligent, making them less able to adapt to change. The researchers also note that their results are similar to those of researcher Jonathan Webb—he found that exposing geckos to warmer temperatures in the nest made them not only duller but less likely to survive once released into the wild. 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

Carbon climate and North Americas oldest boreal trees

first_imgThe researchers used a dual-isotope analysis of tree rings (δ 13 C and δ 18 O; carbon-13 and oxygen-18, respectively) to track changes in iWUE over a 715-year period. Their results showed “a remarkable and unprecedented (59%) iWUE increase over the past 150 y,” the period tracking the onset of major anthropogenic atmospheric carbon emissions. Examination of dual-isotope data from this period revealed two distinct patterns of iWUE activity, each corresponding to two of the three iWUE scenarios described earlier. The first phase, spanning the years 1850 to 1965, corresponded to S1, where ci remains constant in relation to increasing ca. This time period showed a 28% increase in iWUE compared with the pre-industrial average from the preceding 550-year period. By 1965, when ca levels reached 320 ppm however, iWUE activity shifted to reflect a constant ci/ca ratio (0.49), as described in S2, and this was accompanied by an additional 31% rise in iWUE. The rate of increase in iWUE observed in the first phase of the study is among the highest ever seen in the Northern Hemisphere, and remarkable also in that the response occurred in already mature trees. The shift in activity from a constant ci to a proportional Ci/Ca relationship—a change in paradigm from S1 to S2—that took place in the second period beginning in 1965, was also remarkable. No such shift had previously been observed in a North American boreal forest.The observed shift in the trees’ acclimation strategy suggested physiological changes either in A, gs, or both, and so the researchers looked to clues in the dual-isotope analysis to clarify the mechanism at work in both time periods. They found that in the first period, from 1850 to 1965, A (assimilation rate) stimulation by increased CO2 probably drove iWUE increases; but after 1965, the iWUE response likely changed to one dominated by gs, that is, in this case—declining stomatal conductance. In essence, these trees seemed to employ a strategy that maximized carbon gains at relatively low ca, as seen in period 1. However, beginning in 1965, the trees switched over to a drought-avoidance strategy as their photosynthetic apparatus approached a saturation point, after which water losses would be disproportionately high in comparison to carbon gains, were they to maintain a constant ci.Next, the researchers looked at variations in climate in relation to iWUE, examining variables such as soil moisture index, vapor pressure deficit, and temperature. Their analysis showed that, while each of these climate-related factors did have a significant effect on iWUE between 1953 and 2014, each had a maximal effect at a different time frequency. Moreover, the very large increase in iWUE beginning in 1850 could not be attributed to climatic changes such as the hotter/drier conditions that have prevailed since 1965. Evidence indicates colder and wetter conditions in fact prevailed, and the high stomatal conductance necessary for iWUE increases at the observed rate of the 1850 to 1965 period likely would not have been possible in hotter and drier conditions. The climatic trend of hotter and drier conditions may have played a role in facilitating the switch from S1 to S2, however. Perhaps the most important finding of this study though, is the fact that the unprecedented iWUE increases seen since 1850 did not result in substantially higher growth. Looking at ring-width indices from the trees, the researchers found periods of high growth from relatively recent modern times (1980s-1990s) of equivalent magnitude to other periods from well before 1850. The researchers offer several plausible explanations for this lack of apparent growth, ranging from growth of non-stem components of the three, such as root exudates, to nutrient limitations, for example, the effect of phosphorus on biomass growths in white cedars. Regardless, the results of this study serve as cautionary evidence to those developing dynamic global vegetation models (DGVMs) which rest upon the assumption that higher atmospheric carbon necessarily translates to greater carbon storage via photosynthesis to biomass. Thus the authors conclude: “Our results thus suggest that even in favorable conditions for growth, not all trees can take advantage of elevated levels of ca and iWUE. These mechanisms are not typically taken into account by ecophysiological models and DGVMs which may lead to them overestimating any positive effects bestowed by a higher ca on carbon assimilation and fixation. Predictions of elevated future growth and possible alleviating effects on ca might be overly optimistic if the models do not allow for the possibility of constant or even reduced growth in the context of increasing ca.” Claudie Giguere-Croteau and colleagues published their study “North America’s oldest boreal trees are more efficient water users due to increased [CO2], but do not grow faster,” recently in PNAS. Their study of white cedar trees from the southern edge of the North American boreal forest comprises a dual-isotope analysis of rings from 715-year-old trees located around the shores of Lake Duparquet in Quebec. The extreme old age of the trees is significant in that the sampled growth rings provide hundreds of years of climate and growth condition data prior to the onset of the Industrial Revolution and the concomitant increase in atmospheric carbon dioxide (ca), which, by the criteria of this study, began in 1850. As the authors of the study note, “plants have not been exposed to concentrations [of ca] above 290 ppm for at least 650,000 y, so the dynamic carbon–water coupling that prevailed for several millennia could be disrupted with potential, yet uncertain, impacts on hydro-ecosystem functioning.”Elevated ca, in terms of plants’ physiologic response, is known to correspond to iWUE—a measure of carbon uptake per unit of water lost—though iWUE may also be governed by variables such as assimilation rate (A) and stomatal conductance (gs), and how these variables ultimately affect a plant’s internal carbon (ci). The authors cite three possible scenarios that explain tree acclimation processes in response to rising ca in relation to iWUE. Scenario 1 (S1) supposes a constant ci, in which iWUE increases robustly. Scenario 2 (S2) allows for a constant ci/ca ratio, in which iWUE increases moderately. Scenario 3 (S3) assumes a constant difference between ca and ci, whereby iWUE remains constant. S1 seems the most plausible scenario in the face of the CO2 fertilization effect, though few long-term data exist to further elucidate the specific nature of iWUE in a North American boreal forest, and much uncertainty exists in this respect. Against this background, Giguere-Croteau and colleagues present their findings. Thuja occidentalis L (white cedar). Credit: USDA-NRCS PLANTS Database/Wikipedia © 2019 Science X Network In an age of unprecedented high atmospheric carbon dioxide levels, the question of whether or not plants and trees can utilize excess carbon through photosynthesis is one of paramount importance. Researchers have observed what has been called the CO2 fertilization effect, whereby plants’ rates of photosynthesis increase in response to higher levels of CO2 in the atmosphere, although this is thought to be dependent on various other factors such as temperature, moisture, nutrient availability, etc. A group of researchers from Quebec sought to better understand how the oldest boreal trees in North America—Thuja occidentalis L, white cedar—have responded to higher levels of atmospheric CO2 (ca) in terms of these trees’ intrinsic water use efficiency (iWUE). Increase in red spruce growth tied to the Clean Air Act Citation: Carbon, climate, and North America’s oldest boreal trees (2019, February 4) retrieved 18 August 2019 from https://phys.org/news/2019-02-carbon-climate-north-america-oldest.html Journal information: Proceedings of the National Academy of Sciences More information: Claudie Giguère-Croteau et al. North America’s oldest boreal trees are more efficient water users due to increased [CO2], but do not grow faster. PNAS published ahead of print January 28, 2019. doi.org/10.1073/pnas.1816686116 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.last_img read more

Parents are important but so is love

first_imgI’m in love a girl from a different community. Both families are against our marriage. Rajpal, DelhiIt completely depends on you both. Assuming you are matured adults and have confidence in each other. Parents are important but your life and love in your life is equally vital. So, judge the situation and try to convince the families. If they seem adamant, you can decide to be together and get married.I have studied in a Hindi medium school. Now I face major issues with spoken English. How can I improve myself? Also Read – ‘Playing Jojo was emotionally exhausting’N. Gopalan, RaipurYou can enroll in a spoken English class. Alongside, watch English channels, read English newspapers and read it aloud. Whenever possible, talk to your friends and family in English. It’s your confidence that will yield the maximum result. So even if you make mistakes initially, DON’T STOP. My father is an alcoholic and creates trouble every night. My mom is terrified and I am hating it. Sarika, NoidaI understand how ugly this can be. Alcoholism is a disorder that needs to be treated. I’m sure at some point of the day, he is sober. You should speak to him, try to tell him the pain you go through. Use all weapons possible – tears, swears, threats.. Convince him to consult a specialist and take him to a clean-up centre. If he ignores, your mom and you should relocate to a separate address and see if his isolation helps him understand the problem. Also Read – Leslie doing new comedy special with NetflixI had sex with a college mate. I’m very scared of pregnancy. What should I do now?Name unknown, MumbaiFirstly, don’t panic! What’s done cannot be undone. Secondly, do a pregnancy test. Thirdly, do a STD (Sexually Transmitted Disease) test. Hoping all will be fine. But, if there’s anything unwanted, go to a proper gynecologist immediately. From next time, please – ‘Play Safe’!I am 19, my parents want me to get engaged to a family friend’s son. I don’t want it. How to get out of this situation. Rachana, HaryanaRachana – just put your foot down. If need be, speak to the guy. May be, he too is also unsure but is unable to deny the parental pressure! If you are unable to convince, get engaged on a condition – you will not marry before 5 years. Understand the guy, understand whether you like him enough to marry him. If there’s anything wrong, then take it up with your family. All the best!Have a love or life query you cannot find an answer to? Send your questions to – roopshashotm@gmail.comlast_img read more

Delhi to get a bit of mexico

first_imgTo mark the years of artistic, political and economic exchanges between India and Mexico, a replica of The Arch of Labna will be installed at The Garden of Five Senses on Monday. The initiative has been taken by Government of Delhi, Delhi Tourism and Transportation and Development Corporation.The original Arch of Labna was created by Mayan civilization.  The word Labna means ‘abandoned house’. The style of all the original structures is defined by a Mayan architectural style characterised by stone mosaic architectural ornaments. Delhites will soon have their own replica of Labna to admire. To offer a unique experience to the visitors a cycle track will also be introduced for the public. The project was conceived by Julio Faesler, former Ambassador of Mexico to India.last_img read more

Six arrested for illegal sale of arms

first_imgKolkata: The Special Task Force (STF) of Kolkata police on Monday nabbed six people for selling arms illegally after acquiring them from the ordnance factory in West Bengal, an officer said. “We had information of arms being illegally circulated and sold in an area near Babughat. Six suspects have been arrested. We have recovered seven revolvers, one carbine and ten rounds of ammunition from them,” said an STF officer.”They acquired these arms from Icchapur Rifle Factory’s scrap materials. They also sought the help of some of the employees and had paid some amounts as a commission for their help, ” he added.He also said that they have arrested two of the employees of the rifle factory as well.Two of the arrested people acted as the linemen for the Maoists in Bihar and also Nepal.last_img read more

Owner of rehab centre in Behala arrested for abusing minor

first_imgKolkata: The owner of a rehabilitation centre in Behala was arrested for allegedly sexually abusing a 15-year-old girl.Police arrested Sanjay Pal, owner of Suraksha Foundation on the basis of the complaints lodged by the parents of the girl. The parents of the girl alleged that they had admitted their daughter to the centre three months ago to treat her drug abuse. The girl often complained of misbehavior by Pal. She also complained that other inmates were beaten up by Pal and other staff of the Centre with plastic pipes. On Wednesday, when the parents went to the Centre the girl again complained of misbehavior by Pal. The parents raised an alarm. Locals took them to the police station. On the basis of their complaints, Pal was arrested. Police also interrogated the staff of the centre.last_img read more

Who can say no to chocolate

first_imgChocolate comes from The Cacao tree which is called as ‘Food of the Gods’. It is only apt to pair this heavenly ingredient with Cognac also known as ‘Nectar of the Gods’. Get a mental high and your heart pounding with delicious antioxidants that chocolate is made of, with the Cognac and Chocolate Symphony at The Imperial New Delhi. In life these sinful and luxurious pleasures are a treat to the senses. Cognac paired with chocolates and then enjoyed as nightcap has been a tradition to go by. Also Read – ‘Playing Jojo was emotionally exhausting’The Imperial New Delhi presents a delightful way to end a great meal with our house made artisanal chocolates and a crystal glass of the finest and rarest cognacs.Being the trendsetting hotel with an avante garde approach, here is an innovative mixing some creative cocktails based on Cognac and then artfully paired with chocolate. A few of the cocktails are legendary and are served as an ode to patrons by talented bartenders. For instance, a clever old fashioned made with cognac will leave a great impact on your senses. Old school toddy (The Imperial Bartender’s Special) is another fine example of our mixologist’s technique in extracting a fine balance of flavors and colors to create a great cocktail. Also Read – Leslie doing new comedy special with NetflixChoose from an innovative menu featuring Stinger: Cognac, mint liquor and ice cubes; Red Russian: Cognac, vodka, cherry juice and rock ice;  Old Fashioned: Angostura bitter, cognac, sugar cube;  Burnt Orange: Angostura bitter, cognac, orange juice and ice cubes; Bartender special: Cognac, Indian spices, lemon juice, sugar syrup and hot water, and many more satiating concoctions this March.Where: 1911 Bar and Patiala PegWhen: March 15-25AROMAS OF BENGAL Satiate your love for Bengali cuisine as Imperial’s Daniell’s Tavern’s Executive Chef Vishal Atreya brings to your palate, inspired gourmet from Kolkata, the culinary capital of Bengal. From ‘Daab Chingri’ to ‘Shukto’ and ‘Ilish Maach Bhape’, the spices, the flavours and the aroma will delight you in each bite. We invite all you gourmands to take on an epicurean sojourn of East India.Where: Daniell’s Tavern (all day dining restaurant) When: March 10-25last_img read more

BJP activists police clash outside polling booth in Dhanudi

first_imgKOLKATA: Tension ran high at Dhanudi under Bagmundi in Purulia after BJP activists attacked a polling booth and clashed with the police. It was alleged that three ballot boxes were snatched away by a group of people when BJP supporters were staging a protest demonstration outside the polling booth while the election was on. A gang of miscreants allegedly backed by the local BJP leaders tried to storm into booth number 87 at Dhanudi.A clash broke out between the police and BJP workers when the former opposed them from entering the polling booth. Some pelted stones on on-duty policemen. They tried to ransack a portion of the polling booth as well. Also Read – Heavy rain hits traffic, flightsA huge contingent of police rushed to the spot in order to bring the situation under control. They had to resort to lathi charge to disperse the mob. The incident triggered tension amongst voters who were standing in queues since early morning to cast their votes.Local Trinamool Congress leaders alleged that some BJP backed miscreants attempted to loot ballot boxes and terrorise people. They also injured some police personnel in their way. The district BJP leaders, however, allege that a few local TMC workers tried to capture the booth and drive out the election agent of the BJP from booth number 87. The BJP leaders claimed that they staged a demonstration only to protest against TMC workers’ motive to capture the booth. They also claimed that when they were staging protests outside the booth, on-duty police personnel resorted to lathi charge. They, however, denied the allegations of looting ballot boxes.last_img read more