Q3 Theory of Zen stone Physicists may have cracked the case of “Zen” stones balanced on ice pedestals
The stone creates shade, causing variations in sublimation of the surrounding ice. Visit the Small Sea of Lake Baikal in Russia during the winter and you'll likely see an unusual phenomenon: a flat rock balanced on a thin pedestal of ice, akin to stacking Zen stones common to Japanese gardens. The phenomenon is sometimes called a Baikal Zen formation. The typical explanation for how these formations occur is that the rock catches light (and heat) from the Sun and this melts the ice underneath until just a thin pedestal remains to support it. The water under the rock refreezes at night, and it has been suggested that wind may also be a factor. Now, two French physicists believe they have solved the mystery of how these structures form, according to a new paper published in the Proceedings of the National Academy of Sciences—and their solution has nothing to do with the thermal conduction of the stone. Rather, they attribute the formation to a phenomenon known as sublimation, whereby snow or ice evaporates directly into vapor without passing through a water phase. Specifically, the shade provided by the stone hinders the sublimation rates of the surrounding ice in its vicinity, while the ice farther away sublimates at a faster rate. Many similar formations occur naturally in nature, such as hoodoos <https://en.wikipedia.org/wiki/Hoodoo_(geology)> (tall, spindly structures that form over millions of years within sedimentary rock), mushroom rocks <https://en.wikipedia.org/wiki/Mushroom_rock> or rock pedestals (the base has been eroded by strong dusty winds), and glacier tables (a large stone sitting precariously on top of a narrow pedestal of ice). But the underlying mechanisms by which they form can be very different. For instance, as we reported last year <https://arstechnica.com/science/2020/09/mathematicians-may-have-unlocked-the-secret-of-how-stone-forests-form/>, a team of applied mathematicians from New York University studied the so-called "stone forests" common in certain regions of China and Madagascar. These pointed rock formations, like the famed Stone Forest <https://en.wikipedia.org/wiki/Stone_Forest> in China's Yunnan Province, are the result of solids dissolving into liquids in the presence of gravity, which produces natural convective flows. On the surface, these stone forests look rather similar to "penitentes <https://en.wikipedia.org/wiki/Penitente_(snow_formation)>": snowy pillars of ice that form in very dry air found high in the Andean glaciers. Charles Darwin described penitentes in 1839 after a March 1835 excursion in which he squeezed his way through snowfields covered in penitentes on the way from Santiago, Chile, to the Argentine city of Mendoza. Physicists have been able to recreate <https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.96.098502> artificial versions of penitentes in the lab. But penitentes and stone forests are actually quite different in terms of the mechanisms involved in their formation. The spikes of a stone forest are carved by flows, which don't play a big role in the formation of penitentes. Some physicists have suggested <https://gizmodo.com/physicists-unravel-the-longstanding-mystery-of-these-sp-1732684998> that penitentes form when <https://journals.aps.org/pre/abstract/10.1103/PhysRevE.63.056129> sunlight evaporates the snow directly into vapor (sublimation). Tiny crests and troughs form, and sunlight gets trapped within them, creating extra heat that carves out even deeper troughs, and those curved surfaces in turn act as a lens, speeding up the sublimation process even more. An alternative proposal <https://journals.aps.org/pre/abstract/10.1103/PhysRevE.92.033015> adds an additional mechanism to account for the oddly periodic fixed spacing of penitentes: a combination of vapor diffusion and heat transport that produces a steep temperature gradient and, hence, a higher sublimation rate. In the case of the Baikal Zen stone formations, the process seems similar to the sublimation hypothesis for penitentes, according to co-authors Nicolas Taberlet and Nicolas Plihon of CNRS in Lyon, France. Earlier this month, they published a somewhat related study <http://perso.ens-lyon.fr/nicolas.plihon/Publis/Henot_PRL_127.pdf> in Physical Review Letters on the natural formation of glacier tables (a rock supported by a slender column of ice). They were able to produce small-scale artificial glacier tables in a controlled environment and found two competing effects that control the onset of glacier table formation. With smaller stone caps with higher thermal conductivity, geometrical amplification of the heat flux causes the cap to sink into the ice. For a larger cap with less thermal conductivity, a reduction in heat flux arises from the fact that the cap has a higher temperature than the surrounding ice, forming a table. For this latest study, Taberlet and Plihon wanted to explore the underlying mechanisms behind the natural formation of Baikal Zen structures. "The scarcity of the phenomenon stems from the rarity of thick, flat, snow-free layers of ice, which require long-standing cold and dry weather conditions," the authors wrote. "Weather records show that melting of the ice is virtually impossible and that, instead, the weather conditions (wind, temperature, and relative humidity) favor sublimation, which has long been known to be characteristic of the Lake Baikal area." So the researchers set about trying to reproduce the phenomenon in the laboratory to test their hypothesis. They used metal disks as experimental analogs of the stones, placing the disks on the surface of blocks of ice in a commercial lyophilizer. The instrument freezes material, then reduces the pressure and adds heat, such that the frozen water sublimates. The higher reflectivity of the metal disks compared to stones kept the disks from overheating in the lyophilizer's chambers. Extraterrestrial Both aluminum and copper disks produced the Baikal Zen formations, even though copper has almost twice the thermal conductivity of aluminum. The authors concluded that, therefore, the thermal properties of stone were not a crucial factor in the process. "Far from the stone, the sublimation rate is governed by the diffuse sunlight, while in its vicinity the shade it creates inhibits the sublimation process," the authors wrote. "We show that the stone only acts as an umbrella whose shade hinders the sublimation, hence protecting the ice underneath, which leads to the formation of the pedestal." This was subsequently confirmed by numerical modeling simulations. Taberlet and Plihon also found that the dip, or depression, surrounding the pedestal is the result of far infrared radiation emitted by the stone (or disk) itself, which enhances the overall sublimation rate in its vicinity. It's quite different from the process that leads to glacier tables, despite the similar shape of the two formations. In the case of glacier tables, the umbrella effect is only a secondary factor in the underlying mechanism. "Glacier tables appear on low-altitude glaciers when the weather conditions cause the ice to melt instead of to sublimate," the authors wrote. "They form in warm air while the ice remains at 0 degrees Celsius, whereas Zen stones form in air that is colder than the ice." Understanding how these formations occur naturally could help us learn more about other objects in the universe, since ice sublimation has produced penitentes on Pluto and have influenced landscape formation on Mars, Pluto, Ceres, the moons of Jupiter, the moons of Saturn, and several comets. "Indeed, NASA's Europa Lander project aims to seek biosignatures on Jupiter's ice-covered moon, on the surface of which differential sublimation may threaten lander stability, and this needs to be fully understood," the authors concluded. KR How about the theory of salagrama and Lingam stones? KR IRS 17 8 23 On Thu, 17 Aug 2023 at 12:58, 'gopala krishnan' via KeralaIyers < [email protected]> wrote: > *CULTURAL QA 08-2023-17* > > *Q1 Can you find an electrical outlet that has no wires attached > to it?* > > A1 Gopala Krishnan,Former Assistant General Manager 1996-2004 at > Department of Telecom (1966–2004)2m > > I am answering from Chennai, India. In modern wiring *for future > expansion in concealed wiring a puller wire is provided in switch boxes and > spare switches one or two are provided.* The switches will remain without > any connection. When additional light, fan etc. are to be provided these > switches are provided. > > *Similarly UPS wiring may also be available in many switch boxes*, end > insulated and kept. This is for providing UPS supply to additional > equipment if necessary. > > Recently to my interest I found in the switch box in the bottom of > staircase a calling bell to call persons in the first floor, a DC switch. > The bell was not working. When the electrician came and opened the switch > box, he found the switch, having no AC power supply extended, but wired. He > replaced the battery in the bell, and found the calling bell functioning > perfectly. *Immediately I marked the switch as DC switch*. Actually DC > has to be wired separately. Probably the builder intended it can be made > an AC switch, extending power supply and providing an AC bell when required. > > *Q2 How long can I leave a circuit breaker turned off?* > > > > <https://www.quora.com/profile/Izzy-Straus> > > *A2 Izzy Straus. <https://www.quora.com/profile/Izzy-Straus>*, > electrical engineer for 45 years, Sr. Life Member IEEE6y > <https://www.quora.com/How-long-can-I-leave-a-circuit-breaker-turned-off/answer/Izzy-Straus> > > How long can I leave a circuit breaker turned off? > > Izzy Straus's answer: Forever. No current is flowing. It’s just a switch > which is turned off BEFORE the current... > > <https://www.quora.com/How-long-can-I-leave-a-circuit-breaker-turned-off/answer/Izzy-Straus> > > > *Forever.* No current is flowing. It’s just a switch which is turned off > BEFORE the current sensing element of the breaker. So, when it’s off, it’s > disconnected. > > Think of the analogy to a regular ole’ light switch. How long can you > leave it turned off? Saaaaame thing. > > *Q3 What are some of the best rare natural phenomena occurring on > Earth?* > > A3 RI Shohag,10h > > The " Zen Stones " (or "Zen Stones") of *Lake Baikal in Russia.* > > It is a rare and fascinating natural phenomenon to observe, as much for > its aesthetics as for the way in which it is formed. > > *A Zen Stone appears on the surface of a frozen lake* when a stone, > warmed by the sun, emits infrared rays that will melt the ice around it... > except for a thin column under the stone. > > *During the night, the melted ice will freeze again and reinforce the base > of the pedestal.* > > Even if this phenomenon is not exclusive to Lake Baikal, the purity of its > ice gives a special dimension to the photos of these stones. > > *Q4 Is it okay to fix an air conditioner in a home kitchen, or is > this a wrong idea? What are the things I should keep in mind?* > > A4 Gopala Krishnan,Former Assistant General Manager 1996-2004 at > Department of Telecom (1966–2004)Just now > > There is no harm in having an air conditioner in kitchen. *There are > homes fully air-conditioned with centralized air conditioning*. I > recollect the flat in Dubai, where my daughter was living had centralized > AC and kitchen was also air-conditioned. > > But in India kitchen is provided mostly with special fan, which provide > cooling, but will not put out the ignited stove. > > But I have seen some homes with split air- conditioner in kitchen > > *Q5 What are some common signs that indicate the need for > electrical repairs in a home or building?* > > A5 Pramode Mishra, tudied Electrical Engineering at Birsa > Institute of Technology, Sindri (Graduated 1976)Aug 10 > > Here are some of the most common signs that indicate the need for > immediate electrical repair: > > Flickering or dimming lights. This can be a sign of a loose connection, > overloaded circuit, or other problem with the wiring. > > Circuit breakers tripping frequently. This is a sign that the circuit is > being overloaded, which can cause damage to the wiring. > > Outlets or switches that don't work. This can be a sign of a loose > connection, damaged wiring, or other problem. > > Sparks or smoke coming from outlets or switches. This is a serious safety > hazard and should be addressed immediately. > > Burning smell coming from electrical outlets or appliances. This can be a > sign of overheating or a short circuit, which can cause a fire. > > My note- Even in new wiring if there is slight loose connection at any > point in an airconditioner circuit, rubber burning while working. > > Electrical shocks. This is a serious safety hazard and should be > addressed immediately. > > *If you notice any of these signs, it is important to call a qualified > electrician to inspect your electrical* system and make repairs as > needed. Electrical problems can be dangerous, so it is important to take > action promptly. > > Here are some additional tips for staying safe around electrical repairs: > > Always turn off the power to the affected area before beginning any > repairs. > > Use insulated tools and wear gloves when working with electrical wiring. > > My note- Nowadays rubber footmats are available. Put two dry rubber mats one > over the other and stand and work if gloves are inconvenient . > > Be careful not to overload circuits. > > Have your electrical system inspected by a qualified electrician regularly. > > By following these tips, you can help to prevent electrical problems and > keep yourself safe > > *All the above QA are from Quora digest to me on 17-08- 2023.* *Quora > answers need not be 100% correct answers . Compiled **and posted by R. > Gopala krishnan, on 17-08-2023* > > -- > On Facebook, please join https://www.facebook.com/groups/keralaiyerstrust > > We are now on Telegram Mobile App also, please join > > Pattars/Kerala Iyers Discussions: https://t.me/PattarsGroup > > Kerala Iyers Trust Decisions only posts : https://t.me/KeralaIyersTrust > > Kerala Iyers Trust Group for Discussions: > https://t.me/KeralaIyersTrustGroup > --- > You received this message because you are subscribed to the Google Groups > "KeralaIyers" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/keralaiyers/1307819530.736872.1692257307221%40mail.yahoo.com > <https://groups.google.com/d/msgid/keralaiyers/1307819530.736872.1692257307221%40mail.yahoo.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Thatha_Patty" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/thatha_patty/CAL5XZoo7a%3DKyYDD6Py2Bq1cVdOTKxzehucRZF0YWvRDysMJLiA%40mail.gmail.com.
