(a slightly delayed post!)
March 5 was Open day at IISc, the day of the year when the entire institute is open to public with interesting events, demos and talks. As a single day is super short to see all the interesting stuff, here’s what we could grab:
We began with Center for Cryogenic Technology (as it always seemed a very fancy place). Cryogenics deals with the study of production and effects of very low temperatures, (lower than −150 °C (123 K)). At such low temperatures,molecular motion in materials becomes very low resulting in a highly ordered state of matter. This alters some of the physical properties of materials. Liquid nitrogen and liquid helium are commonly used cryogenic fluids.
The first demo was of a cryo-jet, made from a very simple apparatus: a string tied at two rigid ends (a tree and a wall about 50-60m apart) and a plastic bottle placed at one of the ends using two hooks(string directs the bottle to a defined trajectory).Water was filled first in the bottle followed by liquid nitrogen. As soon as liquid nitrogen comes in contact with water, it starts to evaporate much faster (than if it were alone). A small hole in the bottle cap acts as a nozzle, which is initially blocked and later unblocked. As soon as it is unblocked, the bottle shoots away towards the other end. As soon as nitrogen starts to evaporate, it needs much more volume and therefore rushes out through the nozzle, pulling the bottle away in one direction.
Next demo was dipping various objects in liquid nitrogen and observing the change in their physical properties. The demonstrating student took a rubber pipe dipped it in liquid nitrogen tank for a few seconds. When it was removed, it was super brittle (until it reaches back to atm. temperature). They also made instant ice-cream by dipping sweet milk mixture for a few seconds in liquid N2.
Later we saw liquefaction of Oxygen using liquid nitrogen. Gaseous Oxygen was filled in a balloon which was in turn connected to a glass bulb. When the bulb was immersed in liquid nitrogen container, Oxygen inside the glass bulb was cooled and liquefied and thus,volume of balloon shrunk. When the bulb was removed away from the liquid nitrogen, the O2 converted back to gas and the balloon volume increased.
Resistance of materials also changes when subjected to ultra low temperatures. We saw a light bulb demo, where the connecting copper wire, when dipped in liquid nitrogen caused the bulb to glow brighter, as wire resistance reduced, than when it wasn’t ultra-cooled. Transmission losses during electricity transfer could be reduced by lowering the resistance of the cables. The challenge is maintaining the very low temperatures.
Magnetic levitation demos are always magical. A trail of permanent magnets was constructed and a superconductor (a special alloy dipped in cryogenic fluid for a few seconds) was put on the trail to navigate. The superconductor maintains its orientation due to pinning effect, and orbits around the trail.
Next to Cryogenics were demos by IISc undergraduates and we stopped to glance.
One of the fun demos was understanding a Faraday cage using soap bubbles. A closed conducting surface shields its interior from external electric fields, and is called a Faraday cage. A soap bubble was blown on a smooth surface and then a static charged plastic bottle was brought closer. The bubble moved towards the bottle. Then another bubble was blown inside the first bubble and then when the bottle was brought closer, the inner bubble didn’t react, only the outer one did.
Brachistochrone (Least time) problem demo: The setup here consisted of two different paths between two points, a linear one and the other an inverted cycloid. The challenge was to guess which of the two paths would be faster for an object starting at rest from the top point to reach the bottom. The linear path has the shortest distance but the inverted cycloid takes less time for an object. It is because the object accelerates much faster due to rapid descent in the beginning than the linear path and then covers the rest of the path due to the built momentum.
We later saw samples of various types of rocks, demo on ground water conversation and various chemistry demos, math puzzles and more..
Then we went to Center for Product Design & Manufacturing (CPDM).Lots of models and prototypes of novel concepts are always a visual treat. Among the prototypes we saw were those of foldable helmet to minimize storage space, design of a Surgical 4 state chair using a single actuator, a light weight and affordable segway and others.
At 1pm was one of the air-show slots so we went to the Aerospace department launchpad to watch in action the planes and quadcopters built by hobbyists and the department. It was super hot but the crowd was still very enthusiastic.
After lunch and a bit of rest, we caught up the last set of demos at Electrical Communication Engineering (ECE) department.
Intruder detection with PIR sensors : The goal of the project is to detect and classify various intruders (human,animal) in outdoor scenarios, using low cost sensor network (array of Passive Infrared Sensors (PIR). The motivation of the work comes from the undesirable conflicts that occur occasionally in regions close to forests, either due to human intrusion in the wild or wild-life intrusion in human habitations. An array of 8 PIR sensors is used to classify clutter (movement of vegetation) from various intrusions (animals and humans) using machine learning.
Open shoe project: This project is being developed in collaboration with KTH Sweden, and consists of a foot mounted inertial navigation system. Each module consists of several Inertial Measurement Units (IMUs) along with Bluetooth and the module sends heading and displacement data,to another device, say a phone on which the position of the wearer can be tracked. One of the applications of such technology would be to improve safety of folks like firefighters, by accurately tracking and guiding their indoor navigation as GPS signals are not available accurately. The project is completely open source, check out more details here.
The demos ended by 5pm and it was a fun filled Saturday. We also missed a lot of departments demos (Neuroscience, CSA, CEDT, NanoTech..), some other time later..
some of the perks of living in Bangalore (and close to IISc). =)