New theory and old equations may explain causes of shipsinking freak waves

first_img Citation: New theory (and old equations) may explain causes of ship-sinking freak waves (2006, September 13) retrieved 18 August 2019 from 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. “The freak wave a phenomenon is important to understand since it may be the cause of serious accidents involving oil platforms and ocean-going ships,” said Marklund. “If a greater understanding of the mechanisms behind these waves is obtained, one may, for example, in the future combine this with observational and statistical tools in order to construct warning systems.” Shukla, Marklund and their colleagues built their theory on a two-wave system, where two waves interact nonlinearly, which is described by the Schrodinger equations. These quantum mechanics equations, originally developed to describe the wave-like behavior of electrons in atoms, have since been used for a variety of wave systems. The scientists found that two-wave cases behave much differently than single waves, which exhibit standard instabilities and dissolve into a wide spectrum of waves.”We have presented a theoretical study of the modulational instabilities of a pair of nonlinearly interacting two-dimensional waves in deep water, and have shown that the full dynamics of these interacting waves gives rise to localized large-amplitude wave packets,” wrote the scientists in a recent issue of Physical Review Letters. “[T]wo water waves can, when nonlinear interactions are taken into account, give rise to novel behavior such as the formation of large-amplitude coherent wave packets with amplitudes more than 3 times the ones of the initial waves.”Using the Schrodinger equations, the scientists studied the impact of different wave speeds and different angles at which two waves intersect. The team found that for a certain, relatively small angle, a new instability arises with a “maximum growth rate that is more than twice as large as the ones for the single wave cases,” they report. Two waves meeting at such an angle would escape normal stabilizing effects and exhibit constructive interference that would result in a freak wave. Strong currents can help further by “focusing” waves, continually building them up to giant sizes.”This particular piece of research describes a possible mechanism behind rogue wave formation,” said Marklund. “In order to statistically predict their location, one will need further observations and analysis of such data using various methods, in particular statistical analysis and computer simulations.”Citation: Shukla, P.K., Kourakis, I., Eliasson, B., Marklund, M. and Stenflo, L. “Instability and Evolution of Nonlinearly Interacting Water Waves.” Physical Review Letters. 97, 094501 (2006).By Lisa Zyga, Copyright 2006 On a stormy April day in 1995, the RMS Queen Elizabeth 2 was sailing in the North Atlantic when the ocean liner dipped into a “hole in the sea.” Out of the darkness, a towering 95-foot wave threatened to crash down upon the vessel, which the 70,000-ton ship attempted to surf in order to avoid being pummeled to the bottom of the ocean. Explore furthercenter_img A freak wave approached this oil freighter, the Esso Languedoc, near Durban, South Africa in 1980. The masts are about 82 feet above sea level, but the wave, which broke over the deck, caused only minor damage. Photo credit: Philippe Lijour. Fortunately, the ship and passengers survived, but the instance occurred just months after the first scientific recording confirmed the validity of old sailors’ tales once considered skeptical: the existence–and prevalence–of freakishly giant waves, also known as rogue waves.Before the first laser measurement of a freak wave in January 1995, oceanographers and mathematicians predicted that such monster waves should only occur about once every 10,000 years. But as the occurrence inspired satellite measurements, scientists observed many more freak waves than theory predicted. In fact, observations imply that a handful of these waves is occurring at every moment somewhere on the ocean. Although it’s controversial just how many ships and lives have been lost in modern times due to these fairly common giant waves, most ships today are only built to withstand waves up to 50 feet tall–while freak waves have been calculated to reach heights of up to 198 feet. Technically, a freak wave is defined as a wave that is twice the “significant wave height,” which is the mean of the largest third of waves in an area.Intrigued and terrified by freak waves and their potential for swallowing giant ships whole (from oil rigs to cruise ships), scientists are trying to formulate a theory or theories to describe the evolution of these mythical realities. Recently, scientists from Sweden and Germany, Padma Shukla et al., have presented the first analysis and simulation of its kind for the instability of nonlinear waves interacting in deep water. In the past, nonlinear theories have seemed capable of explaining the greater prevalence of rogue waves than previous theories which were linear.”The basic reason for the occurrence of freak waves seems to be what is known as nonlinear wave interactions–by a certain mechanism there is an energy exchange between the waves resulting in a large growth in wave amplitude, much larger than what would be possible through ordinary linear superposition of waves,” coauthor Mattias Marklund told Nearly all waves originate as ripples on the water’s surface blown by the wind. (The exception is tsunamis, which are caused by seismic tremors on the ocean floor and only become dangerous when they reach the shore.) Most waves, however, die down due to viscosity in the water, unless heavy winds cause the swells to increase. Scientists believe that heavy winds–especially when blowing in the opposite direction of the water current–play a large role in forming freak waves. This idea may explain why locations with strong currents (e.g. the Agulhas off Africa and Gulf Stream off the U.S., including the Bermuda Triangle) have a history of reported freak waves. The ‘freak wave’ mythlast_img read more

Xray techniques help art historians verify Rembrandt sketch

first_img © 2011 The experts turned to the modern science of x-ray imaging for answers. The scientific work showed an unfinished self-portrait by Rembrandt under the paint surface.The ESRF and Brookhaven sites performed the scientific explorations. Ernst van de Wetering, emeritus professor of art history at the University of Amsterdam and head of the Rembrandt Research Project, said the evidence was clear that this is a Rembrandt. Copper distribution map from XRF analysis with the contours superimposed on the hidden portrait (centre) (reconstruction by E. Van de Wetering). Comparison of the outline to other self portraits by Rembrandt van Rijn: Rembrandt as a young man (left), (© Metropolitan Museum of Art, NY, USA); Self portrait of Rembrandt (right), dated 1630, (© National museum, Stockholm). The scanning technology that was used at ESRF was a dual energy X-ray imaging technique. The Brookhaven National Lab used used Macro-scanning X-Ray Fluorescence spectrometry (MA-XRF). Central to Brookhaven’s contribution was its new fluorescence microprobe system that can scan surfaces with high definition. The XRF technique was used with this new “Maia” detector system.The detector can produce high definition maps of the spatial distribution of different chemical elements in a painting. The painting is placed on a motorized scanning stage that allows for element-specific mapping. A pencil beam of synchrotron radiation (SR) is swept over the painting. What do Facebook and Rembrandt have in common? Everything More information: … rs-of-a-Purported-Re … =1359& … / Explore furthercenter_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. KES imaging of the painting Old Man with a Beard at beamline ID17 allowed a quick visualisation of the distribution of heavy elements in the paintings. Based on these results, the presence of a complete second figure could be excluded. Image credit: Koen Janssens. ( — Advanced imaging technology from the Brookhaven Labs and the European Synchrotron Radiation Facility (ESRF) in Grenoble has revealed an authentic Rembrandt self-portrait in an art authenticity effort involving leading art historians and scientists at the two labs. The hunt for authenticity all began when a private collector showed art historians in Amsterdam a small panel “Old Man with a Beard” from about 1630. The collector wanted to know if it was a Rembrandt. Citation: X-ray techniques help art historians verify Rembrandt sketch (2011, December 4) retrieved 18 August 2019 from The Maia detector, according to the publication Lab Manager, which details the technology used in the Rembrandt probe, is based on a massively parallel detector array composed of 384 individual detectors, an “on-the-fly” scanning system, and advanced analysis software. The publication reported that the detector was able to image the entire painting in about eight hours, in a task that would normally take about 30 days.In general, X-ray Fluorescence (XRF) is considered a key technology for those in the art world, as it highlights pigments concealed beneath the surface, and has previously been used to authenticate works by Van Gogh and Goya, among other famous artists. The tool is especially helpful as it can determine chemical composition in a nondestructive way; the work of art is left intact.Prof Ernst van de Wetering, an art historian at the Rembrandt House in Amsterdam, and head of the Rembrandt Research Project, had worked meanwhile with his team to examine the sketch for authenticity. The imaging results gave scientific support to authentication, which Prof. van de Wetering announced at the Rembrandt House Museum in Amsterdam on Friday.From 1 May to 1 July 2012 the Rembrandt House Museum is staging a special exhibition of research into ten paintings by Rembrandt and his contemporaries using XRF technology.last_img read more

Researchers use nanoparticles to speed up or slow down angiogenesis

first_img( —Researchers at the University of Southampton in the U.K. have devised a means for using nanoparticles to cause angiogenesis (the growth of new blood vessels) to speed up or slow down. In their paper published in ACS Nano, the researchers describe how they coated gold nanoparticles with peptides to allow for altering the speed at which new blood vessels develop in specific locations in the body. More information: Manipulation of in Vitro Angiogenesis Using Peptide-Coated Gold Nanoparticles, Dorota Bartczak, Otto L. Muskens, Tilman Sanchez-Elsner, Antonios G. Kanaras, and Timothy M. Millar, ACS Nano Article ASAP. demonstrate the deliberate activation or inhibition of invitro angiogenesis using functional peptide coated gold nanoparticles. The peptides, anchored to oligo-ethylene glycol capped gold nanospheres, were designed to selectively interact with cell receptors responsible for activation or inhibition of angiogenesis. The functional particles are shown to influence significantly the extent and morphology of vascular structures, without causing toxicity. Mechanistic studies show that the nanoparticles have the ability to alter the balance between naturally secreted pro- and anti-angiogenic factors, under various biological conditions. Nanoparticle-induced control over angiogenesis opens up new directions in targeted drug delivery and therapy.via Nanotechweb 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. The development of new blood vessels is critical while wounds are healing. It’s also important in helping people recover from accidents or who have tissue damaged by disease. Speeding up angiogenesis can help to speed up recovery times. Sometimes however, angiogenesis can progress incorrectly resulting in the growth of tumors. In these instances, doctors would like to slow or stop the angiogenesis process. In this new effort, the research team has found a new way to accomplish both goals with one new treatment option.The new technique revolves around the use of nanoparticles—very small objects generally not found in nature. In this case, the particles created were made of gold. Because nanoparticles can so easily move around inside the body, the thinking was that nanoparticles could be used to deliver drugs to specific areas of the body where they are needed. In this case, the drugs were peptides that have been shown to speed up angiogenesis when appropriate and to slow the process when tumors have developed. The ability to deliver the drug only to areas where they are needed reduces side-effects.In order for angiogenesis to occur, endothelial cells must be activated by the presence of certain molecules engaging with receptor cells. Over time, researchers have developed various drugs to either stimulate or repress angiogenesis by activating the receptor cells or block them. Such drugs have only been useful for a short duration, however, and most often come with unwanted side effects. In this new effort, the team used nanoparticles to carry and deliver such drugs only to the parts of the body that needed them. They found they could target specific receptor cells that allow for focusing on different diseases. Specifically, they developed three types of peptides for delivery via nanoparticles: those that bind and promote cascade growth of blood vessels, those that block receptors cells from receiving signals, and those that serve as a control and do nothing. They report that they were successful in delivering all three types to target areas and that doing so caused the expected changes in angiogenesis rates. Cholesterol sets off chaotic blood vessel growth © 2013 Explore further Citation: Researchers use nanoparticles to speed up or slow down angiogenesis (2013, June 24) retrieved 18 August 2019 from Journal information: ACS Nanolast_img read more

Nearly forgotten dinosaur bone found to belong to ancient hippolike creature

center_img Explore further © 2018 The researchers report that the bone was found sometime during the 1950s when workers building a dam came across it. The bone was found near the town of Tsuchiyu Onsen in Fukushima. Archeologists called to recover the fossil described it in a note as a dinosaur femur, and later placed it on a shelf in a museum. It was there on that shelf that the researchers with this new effort found the bone. Testing showed the fossil was from approximately 15.9 million years ago (long past the age of the dinosaurs) and that it was actually the fossilized remains of a Paleoparadoxia femur.Paleoparadoxia resembled the modern hippopotamus—prior research has shown that they were plant eaters and grew to approximately two meters in length. They lived in what is now the Pacific Ocean from 20 to 10 million years ago, with a range running from Alaska to Japan and as far south as Mexico. They were also once thought to be amphibious, but more recent research has shown that they were true marine animals, spending most of their time crawling around on the ocean floor eating.The researchers report their work was made easier by the hand-written note left by the original investigators along with the fossil describing where it had been found. That allowed the researchers to return to the dig site to further investigate its history and to provide material for dating the fossil. Instead of testing the thigh bone directly, the team tested rock from the dig site, which contained datable crystal zircons. After measuring the fossil, the researchers used it to create a 3-D model of the creature when it was alive. They report that due to the condition of the fossil, the recreation was believed to be the most accurate to date. Citation: Nearly forgotten ‘dinosaur’ bone found to belong to ancient hippo-like creature (2018, July 25) retrieved 18 August 2019 from read more

Colour burst on the ramp

A burst of colours erupted on the ramp as Nachiket Barve presented his Spring Summer 2013 collection. The Mumbai designer, known for streamlined silhouettes, created capes, camisoles, skirts, jumpsuits, shorts, gowns, saris, jackets, dresses and slim pants.  Peplum was one of the highpoints of the collection.  He used cutwork yokes, appliqué, crisscross grid textures, rhomboid detailing, panels, sequins and textures to jazz up the multihued collection.

Visions revisions toast and tea

first_imgTwenty floors above the city, as the day closed in, Tom Alter’s rich voice floated amongst the immaculate crystals and some very fine brew. And Eliot. Reflections, a session of tea and poetry held at Le Meridien was an evening for the connoisseurs. A part of the New Perspective event series at the hotel, Reflections seemed to be the most perfect way to kick off, just like the first flush of tea which is believed to be the best. Bits of Mirza Ghalib and Maulana Azad’s poetry mingled with Eliot’s and were accompanied by some perfect cups of tea and savouries.  Also Read – ‘Playing Jojo was emotionally exhausting’The poetry was interspersed with talks by tea taster and sommelier Anamika Singh. All the brews tasted through the evening have been blended by her. Putting together green and black tea with flowers and herbs from the Himalayas, Singh has managed to concoct some fragrant brews that is subtle, refreshing and rejuvenates like a dream. Singh believes that the Indian customer has not really woken up to the health benefits of tea and the right way to brew it. There is a need to graduate from a glass of chai to a cup of tea.  And to graduate, one needs to learn and the session was quite a start, it is all about what you infuse, says Singh making it clear that teabags just don’t work.  Also Read – Leslie doing new comedy special with NetflixAlter took on the session with an idea a Chinese poem puts forth. After the seventh cup of tea in the day, one can attain salvation. He broke the poetry session in to seven segments starting with the first cup of tea in bed and ending it with the last cup of tea before sleep. While the first cup of tea softly nudges one awake, the second cup of tea is believed to drive away the five causes of sorrow. By the third cup of tea life is set in motion and by the fourth – all the wrong of life passes away through the pores. Fifth cup means purification, the 4’o clock bliss, the sixth calls out from the realms of the immortal and by the seventh cup as the day comes to a close, the stirring of the tea makes the world go round.  ‘When you have the finest tea, it’s sheer poetry and in sheer poetry there is an unforgettable soothing essence of tea. Reflections is the romance of tea and some great food which helps to unwind and start conversations,’ said Alter. Tea became a refuge of sorts and poetry the perfect companion as songs floated in and out creating the perfect evening. Just as being a poet is a lifetime of work, the right cup of tea imbibes the same passion. And bringing both together could not have been more perfect. All of us has at some time or the other tried writing poetry, perhaps it is also time to try and brew a perfect cup of tea as well.last_img read more

CESC irons out power supply woes in city

first_imgKolkata: The devastating norwester on Tuesday evening disrupted power supply, especially in areas where the city is served by overhead wires. The impact could have been worse, as the city’s underground cables remained largely unaffected. There were, however, a number of cases where lamp posts belonging to other agencies like Kolkata Municipal Corporation (KMC) were also affected. Amongst the affected areas were the Northern and Eastern parts of the city, including Patuli, Panchasayar, Survey Park, Lake Town, Bangur, Dum Dum, Kamarhati, Khardah, Sodepur, Howrah and Serampore. Also Read – Heavy rain hits traffic, flightsAs usual, the norwester affected electricity supply and there was a sharp surge in emergency telephone calls (1912) throughout the night. Fault report calls after the norwester rose to a record 36,000, against the average count of 4,000. CESC emergency repair services started restoration work immediately and more than 1,500 men worked throughout the night.According to a CESC spokesman, “Working on a day-and-night basis, more than 70 percent of the faults could be restored through the night and it is expected that normalcy will be restored in most cases by Wednesday afternoon.” Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed”Fortunately, there have been no major outages and all the Municipal drainage pumping stations worked smoothly at a trying time. We are keeping constant touch with the Municipalities and are ready to take every step to alleviate the suffering of citizens,” he said.Following the heavy rains, there was a noticeable fall in power demand on Wednesday, with the demand at 11.00 am being 1,428 MW, while the maximum demand met on Tuesday was 1,868 MW. More than 6,000 CESC representatives are on special alert and the CESC Disaster Management Cell will keep watch till normalcy returns.last_img read more

Kolkata Metro sees hike in number of passengers

first_imgKolkata: Metro Railway has carried more number of passengers in the first three and half months of this financial year, against the corresponding period of the previous year.A spokesperson of Kolkata Metro informed that during this period (i.e. from April 1 to mid July) 5.92 crore passengers have travelled by Metro, against 5.81 crore passengers last year. “The increase has been around 1.83 percent from last year,” the spokesperson added.The earnings were also raised to Rs 56.96 crore during the same period this year, compared to Rs. 55.17 crore last year, thereby registering an increase of 3.25 percent. At present, Metro Railway has 14 AC rakes and 13 non-AC rakes operating in the 27 km-long line from Noapara in the North to Kavi Subhash station in the South. Also Read – Naka checking to be stricter to rein in speed demonsFour state-of-the-art AC rakes from Integral Coach Factory (ICF) in Perambur have already reached the city and the Metro authorities hope to introduce them before the Pujas. The Metro is gradually working towards replacing its old rakes, which have been a cause of worry for the authorities as they are often developing technical snags. Kolkata Metro has ordered 14 rakes from M/s Dalian Locomotives Ltd. of China, among which the first rake is expected in August.last_img read more

CM to inaugurate Baruipur Central Correctional Home on Wednesday

first_imgKolkata: The Baruipur Central Correctional Home will be inaugurated by Chief Minister Mamata Banerjee by remote control from Nabanna on Wednesday, November 14. The state government will initially shift 700 inmates from Alipore Central Correctional Home (ACCH) to Baruipur and will gradually shift all those lodged in ACCH phase-wise.A senior official of the state Correctional Administration department said that the Baruipur Central Correctional Home (BCCH) has the capacity to house as many as 4,000 inmates. State Correctional Administration minister Ujjal Biswas, Speaker of the West Bengal Legislative Assembly Biman Banerjee and senior officials of the Correctional Administration (CA) department will be present at the inaugural programme at Dhopagachi in Baruipur, where the facility has come up. Also Read – Rain batters Kolkata, cripples normal life”We have given special emphasis on security at BCCH and have taken all possible measures for foolproof security mechanism,” said Ujjal Biswas, minister of state, CA department. Among the 700 inmates who will be shifted in the first phase, 200 are convicts and 500 are under-trials. The Kolkata Metropolitan Development Authority (KMDA) has completed the entire work for the infrastructure of BCCH that includes drinking water, drainage, lighting and most importantly, the approach road leading to the correctional home. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killed”Truckloads of construction material was brought for construction work of the prison through the approach road, which resulted in extremely poor condition of the roads. Sprucing up the road was a tough ask and our engineers worked on a war footing to repair the road,” said a senior official of KMDA. The present accommodation capacity of the 112-year-old ACCH is 1,900. But there are above 2,200 inmates at present. In the correctional home, there are many cells which are of immense historical importance and according to an official of the correctional home, those are now heritage sites. There are around 30 heritage cells. There is a single-storeyed building in which Jawaharlal Nehru was imprisoned by the British for three to four months in 1934. There is another two-storeyed heritage building with ten lockups in each floor, where freedom fighters, including Chittaranjan Das, Jatindra Mohan Sengupta, Bidhan Chandra Roy and Netaji Subhash Chandra Bose were imprisoned in the 1930s.last_img read more