Can an insect teach architecture?

Can you guess what the above pic is about?

These giant sky-lantern shaped architecture on the rural landscape of Ethiopia are meant for harvesting water from the air, known as the Warkawater Project Architecture and Vision group. Warka is the name of a common Ethiopian fig tree.

The next question could be: Well, how does it work?

The detail may not be given by the key designer of the group, Arturo Vittori, but he discusses how such beautiful structures are built out of simple stuff and his vision towards changing the deprived areas where women and children spend a long journey just to collect water from the available resources.

Not only the journey is long, the water resources are not clean not and there are high risks of rape and abduction.

Now let’s get back to the question: what could be the engineering mechanism behind the architecture? Don’t laugh, an insect might be the best buddy to answer you.

Namib Beetle

Namib Beetle

Namib Beetles or the Namibian Desert Beetles (Stenocara gracilipes) are found in the Namib Desert of the southwest coast of Africa. It is one of the driest desert of the world. Despite the arid climate, Namib Beetles know how to survive. Their wind-covering shells have a perfect combination of uneven hydrophilic (water attracting) and hydrophobic surfaces (water repelling) which finally helps them to store water from a moist surrounding.

The idea of fog harvesting is not new. In fact, one should know this Indian and ex-IItian chap, named

Shreerang Chhatre, who came into the news during his PhD+MBA program in MIT for developing a mesh that can harvest water from the moist. The Namib Beetle purely inspired him (a nice presentation here) and if such an inspiration comes into a practical implementation, it is called biomimicry or biomimetics (e.g. Velcro tapes mimic burrs).

Origami+optics=Foldscope, a poor man’s microscope

When I typed microscope in google, I found the following advertisement from eBay India.

Ebay_microscope_adFrom that we get the idea that microscope cost in India varies in the range: ₹1,500-7,000, which may not sound too cheap to be provided all health centers for diagnostic requirements in India or many other countries. Now Manu Prakash,  who is presently an assistant professor in the Bioengineering Dept. of Stanford University (an IIT Kanpur alumni as well), came up with an innovative invention: the Foldscope. It’s a microscope obtained just by folding papers in a way that a 2.4mm ball lens can be mounted by using the capillary-encapsulation  technology. Manu claimed that the whole fabrication costs around 50 cents which will be below ₹50 in Indian market. Watch out this brilliant TED show.

Could you ever imagine it? He called it a use-and-through microscope! The invention sounds like a revolution!

 

“It doesn’t matter, does it anti-matter ?”

What could be your worst enemy whom you will always feel afraid to touch? He/she looks like you, but he/she is exactly opposite of you, your anti-matter. He/she can exactly perform the trick that you always can do. Because you both preserve a symmetry called the CPT symmetry. C stands for Charge conjugation, P stands for Parity transformation, and T means Time reversal. So even if your anti-matter looks like your twin, once you two come into touch, you both get annihilated.

Anti-matter is made of fundamental particles and we call them anti-particles. Like positron is electron’s anti-particle. Existence of positron was predicted by Paul Dirac in 1928 when found two solutions, one with positive and other negative energy, of the relativistic version of the Schroedinger’s equation (Now we call it Dirac equation). Particles obeying Dirac equation having positive energies and -e charges are electrons, and particles with negative energies and +e charges (the opposite sign in the charge is followed by the C symmetry) are positrons. Four years later positrons were discovered by C. D. Anderson in 1932 and this discovery awarded him Nobel prize in 1936. Similar many other anti-particles, e.g. antiprotons (by Emilio Segrè and Owen Chamberlain in 1955), antineutron (by Bruce Cork in 1956) and probably many others later on. When a particle collides its antparticle they both disappear by emitting energy as a photon (particle version of light). A photon is its own antiparticle and hence it automatically satisfies this collision rule.

However, to see a real matter made out of antiparticles we first need to build a matter, whose smallest unit is the atom. That means to create anti-partner of hydrogen, we need to bring an antiproton and a positron (antielectron) together in a similar way such that the positron orbits around the antiproton. Now this situation is very tricky to produce in the lab since anything in our world is made of matters, so any antiparticle once gets created will interact with its particle counter part present in the real world stuff (say, air, table, wall, etc.) and get annihilated.

 

The ASACUSA experiment at CERN (Courtesy: CERN)

This is a remarkable achievement since now probably can attempt to answer a few fundamental question:This week people in CERN’s ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) have claimed in their Nature Communication paper the success of creating 80 antihydrogen atoms by applying magnetic fields, detected 2.7 meter downstream after their creation.

1. Do antimatters obey CPT symmetry?

2. Will antihydrogen show the same spectral lines as normal hydrogen does?

3. Why galaxies and stars made out of antimatters have not been observed yet, whereas the Big Bang Theory supports equal amount of matter and antimatter at the beginning of the universe?

3. Do antimatters feel antigravity (instead of getting attracted like matters, two antimatters can feel repulsion from each other) ?

4. Can we use matter and antimatter annihilation energy to fuel up high-speed spaceships?

Useful links:

Antihydrogen project (Max-Planck institute) 

The matter-antimatter asymmetry problem (article from CERN)

The other side (my previous blog post)

Beer prank: a lesson to fluid-dynamics

I might be a bit late, already this has come in the news: A common beer bottle prank can teach a lot about fluid dynamics. The prank is the following. When you are in a party and you find your long-term enemy at the same party, you just approach him/her, say “Hello!” and hit the mouth of his/her beer bottle by the bottom of your own bottle. Voila! Your enemy will watch all of his/her beer erupting out as foam and leaving almost nothing to drink inside his/her bottle.

Javier Rodríguez-Rodríguez, Almudena Casado, and Daniel Fuster explained this weird effect in the last Annual Meeting of the APS Division of Fluid Dynamics by using a well-known phenomenon in fluid-dynamics called cavitation. Cavitation is the formation of vapor cavity/void/bubble due to the act of reduced pressure in a liquid.

So probably the above video says every thing. Nevertheless, let me try to put this in my own language. A sudden hit on the mouth of the bottle generates a shock wave, causing a sudden rise in pressure and creates a compression wave. When the compression wave hits bottom wall of the beer bottle, it gets reflected and forms an expansion (compression in the opposite direction) wave. During the expansion, pressure is reduced, which causes cavitation in the liquid. Thus throughout the beer liquid a train of compression and expansion waves form, which break the larger bubbles into daughter bubbles of smaller radii. These daughter bubbles move rapidly towards the neck of the bottle in the form of bubble-plumes. Since the surface of the neck is open and the daughter bubble’s motion is so fast, it finally erupts out by exhausting almost all the liquid inside the bottle.

Rodríguez said that understanding this kind of phenomenon may help to understand many other natural caviatation events, e.g. volcanic carbon dioxide in 1986 Lake Nyon disaster in Cameroon. His group submitted the explanation in the arXiv.org.

Now if you haven’t tried this prank yet, go and try it. But be aware of accidents, as the foam always doesn’t not come out instantly, it does certainly.

Now do you know (click if you don’t)

Why do bubbles in Guinness sink?

How To Make A Beer Freeze Instantly?

What happens when you do the same “hit beer bottle prank” with water inside instead of beer?

Physics and Entertainment

Do you think physics are fun only for curious people and the real entertainments are matters of art and skill (e.g. movies, games, and sports)? If you think so, then you are absolutely wrong!

Tennis for two ( Photo credit:  Brookhaven National Laboratory)

Tennis for Two ( Photo credit: Brookhaven National Laboratory)

The first video game, which was shooting with a light flash from a cathode ray tube (CRT), was invented by Thomas T. Goldsmith Jr. and Estle Ray Mann in 1947. The shooting was controlled by the knobs that are used to control the trajectory of CRT’s light beam. The inventors named the device Cathode-Ray Tube Amusement Device. Later in 1958, William Higinbotham of Brookhaven National Laboratory extended this idea to attract the visitors and get a break from the monotony of research. Higinbotham was a physicist, so he used cathode ray oscilloscope (CRO), which I guess any physics student uses at least once in life. His game was called Tennis for Two.

Now another excellent entertainment stuff came from IBM, which is a movie made out atoms only. The movie name is A Boy And His Atom . The atoms were imaged from the scanning tunneling microscopy (STM) measurement (thanks to quantum mechanics!).

How was the movie made?

I am grateful to Prof. Shobhana Narsimhan of JNCASR, Bangalore, who sent us the youtube links.

Useful links:

Install Tennis for Two in Windows.

IBM’s featured research

Let there be light : a brilliant TED talk by Prof. Harald Haas

I just came across this beautiful TED talk by Prof. Harald Haas of University of Edinburgh, UK. He explains and demonstrates the upcoming Li-fi technology using the visible light to get a wireless communication. Li-fi replaces our commonplace wi-fi technology that uses microwaves for data transfer. The key role in this technology is played by the light emitting diodes (LEDs), whose off and on state can be exploited as digital signals.

I could not get time to go into detail, but this article has a nice introduction of this promising technology.

Surface tension: keeping you tied to the water surface

A few days ago I was chatting to one friend in facebook, who has her BSc first year exam ahead. She brought me down to my memory lane where we had a course called general properties of matter (in short GPM) in BSc. It had stuff like fluid mechanics, surface tension, elasticity. I used to hate the course since many things were quite obscure and everything sounded very mechanical (just like derivations and digestion of formulas).

Nonetheless, a few days after the conversation I found someone sharing this besutiful pic on my facebook wall.

Wasp floating due to surface tension

Yes, it is the surface tension of liquid that lets the wasp float on the water.

Do you know the Science Guy (Bill Nye)? Here is a funny video from the 90’s TV show. See if you can understand all the demos (specifically the balloon one).

Now water striders, ants, wasps, and Jesus Lizard can walk on the water. What about us, the homo sapiens? There is something called Liquid Mountaineering. Watch the crazy video below.