That Time We Flew Past Pluto…

New superglue allows for bonding stretchable hydrogels

A team of researchers at Johannes Kepler University Linz has developed a new type of glue that can be used to bond hydrogels to other hard or soft objects. In their paper published on the open-access site Science Advances, the group explains their development process, the structure of the glue, how it works and in what ways.

Hydrogels, as the name suggests, are materials made mainly out of water. They are typically rubbery and are often elastic. Many of them have been developed to allow for the creation of materials that are more like those found in living creatures. Some examples include soft contact lenses, soft bone replacement in the vertebrae and even jelly-like robots. But one thing that has been holding back more advanced applications is the inability to glue or bond hydrogels with other objects in ways that allow for bending or stretching, or even for attaching well to hard objects. In this new effort, the researchers report they have developed a glue that solves this problem.

Read more.

What can we learn from ants and plants?  

That’s what IBMer Mauro Martino set out to answer in his award-winning data visualization, Network Earth. It explores nature’s interconnected relationships, and how they affect each other and our planet. By making the complex but important topics easier to visualize, we hope to help make more of them accessible to all.

Fibonacci sequence in the hiding…

Dissecting Iron Man Suit - An Engineering Analysis

Structural, energy, and thermal analysis of Iron Man Suits specifically Mark I to Mark XLVI which have the following capabilities in common: external armor, supersonic flight, hovering, weaponry, and decoy flares.

1. STRUCTURAL ANALYSIS 

Wear Resistant and Shock Absorbent Exoskeleton  The physical protective value of exoskeleton is its ability to resist any penetrative loads as well as any shock loads. However, the whole thickness of exoskeleton panels should not be too hard because it will pass on the external impact load into the suit’s internal hardware, or even the human body inside it. All of this can be achieved by combining more than one materials; a hard material on the outside and the soft material on the inside

Hard Outer Layer for Penetrative Loads The materials needed for the exoskeleton’s outer layer should be hard and tactile. Titanium Alloy would be an ideal choice. Fiber glass has good tensile strength but not good shear strength, while titanium has both .Titanium Alloy is not only much stronger, but is also lighter than steel, which will provide more fluidity of movement compared to any heavy material counterparts.

Ductile Inner Layer for Shock Loads There should be a soft inner linings behind titanium panels to serve as shock absorbent. Sorbothane is a material that is extremely soft and has the ability to convert shock loads into heat transfer at a molecular level. It is a proprietary, visco-elastic polymer. Visco-elastic means that a material exhibits properties of both liquids (viscous solutions) and solids (elastic materials).

Sorbothane is a thermoset, polyether-based, polyurethane material. Sorbothane combines shock absorption, good memory, vibration isolation and vibration damping characteristics. In addition, Sorbothane is a very effective acoustic damper and absorber. Even if one drops an egg from the top of a building into a bed of sorbothane, this remarkable material is soft enough to cushion the impact and would not allow the egg to break.

This technique of having a hard material on the outside and the soft material on the inside is not new. It has been used for centuries in Japan for making samurai swords. The hardness of its outer layer give the swords its cutting edge and penetrative power, and its ductility allows it to absorb shock loads when it strikes or struck. 

2. ENERGY ANALYSIS : Hovering Capability

Hovering using thrusters (aka repulsors) requires tremendous amount of energy, particularly when the suit is used for a long duration. Energy usage for hovering is dependent upon the hovering methods

Magnetic Levitation requires no energy at all, but is limited to the presence of magnetic field.

Ducted and Open Propellers (helicopter blades). Several human powered helicopters have been made overtime that have achieved flight. It has been experimentally recorded that a 78 kg person in a 58 kg copter requires only 1.1 kW to climb using helicopter blades, and only 60 Watts to maintain altitude.

Jet Thrust is the least energy-efficient method. Because thrust-to-weight ratio needs to be greater than 1 to achieve lift-off, a Jet-pack requires over 1KN of thrust force, depending on the weight of the jet and the person. If wings are attached to the jet-pack, horizontal flight can be achieved with thrust to weight ratio lower than 1, thus improving the duration of the flight and its range.There have been jet-packs made in the past, most iconic display of it was in 1994 Olympics opening ceremony. The fuel used in the jet-pack was mostly hydrogen peroxide. It provides thrust at low temperature compared to other fuels. However, it has low energy density of 810 Wh/kg, giving the jet-packs up to only 30 seconds of flight-time. Jet’s flight time is limited even by using energy-rich fossil fuel. Yves Rossy (aka Jet Man) has successfully used kerosene oil in his flight, but the thruster jets have to be pushed away from the body for safety. His suit allows only several minutes of flight. In addition, if a heavier suit (greater than 25 kg) is used, hydraulics are needed, which would require additional energy and slow down mobility. The Iron Monger suit was an example of hydraulic-driven mobility suit.

3. POWER SOURCE

Tony Stark manages the suit’s energy requirements, including thermal management and artificial intelligence system, through the fictional arc reactor. The reactor is able to provides almost limitless clean energy despite being a very small device. In real life, the only thing that has an energy density comparable to the arc reactor, and would meet all the energy requirements of the suit would be nuclear power. Uranium (fission) energy density is 80.620.000 MJ/kg. However, nuclear power is not suitable to be harnessed in a manned suit, since it generates a tremendous amount of heat.

A more practical solution would be a battery energy-storage. If lithium batteries are used on propeller blades, minutes-long flight time can be achieved. Furthermore, these batteries can readily power suit’s electrical devices / electronics requirements. Lithium ion battery has energy density of 150 Wh/kg (0.5 MJ/kg). Fossil fuel, on the other hand, have a much higher energy density than batteries, but would require a clunky generator to power the suit’s electrical requirements.

Lithium sulfur batteries have 5 times more energy density compared to lithium ion batteries. Lithium sulfur packs had already powered the longest unmanned flight for more than 30 hours. Unless we discover something like an arc-reactor, lithium sulfur batteries could be just the thing to power up the suit. The downside is, it requires hours of charging for just minutes of usage.

There is an alternative option, though not a ‘reactor’ proper. A compact and high-output generator (standard car alternators crank out 50-70 amps at 12 volts for years, and some can go as high as 150 amps) could be spun by a small and strong output electric motor (all alternators have to do is spin). That motor can be powered by a high density battery like used for electric bikes in the 1500w to 2500w range at 20 something volts. This would power a strong and small motor at 3500 to 4000 rpm for hours. That’s more than enough to create power for a number of systems, if they’re built to take advantage of the amperage. And with new constructions of carbon arrays coming out every day, one or more of those could bring a meaningful electric output increase in an otherwise standard generator, even above what we have in cars now.

4. THERMAL MANAGEMENT 

The suit cannot be hermetically sealed. Human body heat evaporates water from the skin. Therefore, air ventilation is a must to remove them. It is also needed to maintain a good supply of oxygen. So, there must be a structure inside the exoskeleton that allows air flow. This would prevent any internal condensation to settle and will also remove buildup of body heat. The layer of sorbothene would act both as a thermal and an electrical insulator. This means that extreme external temperature would not be transferred to the inner layer. The suit would not get too hot or too cold from the outer environment. There should be small fans to draw and pull air from the ambient in controlled amount, and should be able to exchange hot air. With the technology available today, the thermal management of the suit is easily manageable. There are also solid state devices such as thermal pads and thermoelectric generators. Thermoelectric generators can surfaces hot or cold depending on the polarity of the electric current and thus can be an integral component of the suit for controlling the internal temperature.

Source (x)

Keep reading

These giant mesh nets provide drinking water in the driest desert on Earth.

A sponge can’t soak up mercury. (Video) Facebook | Instagram | Scary Story Website

How did the Greeks know ?

Greeks had a strong geometric approach towards problems and as a result their methods are very intuitive.

In this post, we will look at the Method of exhaustion formulated by Archimedes that stands out as a milestone in the history of mathematics

Method of Exhaustion - Archimedes

                                                       Source

In order to find the bounds of pi, Archimedes came up with a remarkably elegant ‘algorithm’, which is as follows:

Lower bound

Inscribe a n-sided polygon in a circle —> Measure its perimeter(p) —> Measure its diameter(d) —> pi_min = p/d —-> Repeat with  n+1 sides.

Upper bound

Circumscribe a n-sided polygon in a circle —> Measure its perimeter(p) —> Measure its diameter(d) —> pi_max = p/d —-> Repeat with  n+1 sides.

And by following this procedure one could obtain the upper and lower bounds of pi !

Heres an animation made on geogebra for a circle of diameter 1. Watch how the lower and upper bounds vary.

Archimedes did this for a 96 sided polygon and found the value of pi  to be between 3.14103 and 3.1427. This is a good enough approximation for most of the calculations that we do even today!

Happy Holidays !

This month on FYP!

It has been a blissful month in physics with the nobel prize for the work on gravitational waves and LIGO swiftly striking back with the detection of a neutron star merger.

At FYP! we have started to dwell a little bit into the essence of condensed matter physics while exploring some really cool science and engineering along the way.

Here’s what went down on FYP! this month:

Nobel prize in physics article on Gravitational waves

Gravitational waves, Light and Merging neutron stars

Paramagnets and Combinatorics

Diamagnetic levitation - Ig Nobel prize(2000)

Levitating frogs and superconductivity

Revisiting rolling shutter

Cooking with a computer (the importance of a heat sink on a computer)

Cartoon laws of physics

Beautiful proofs (#3) - Euler’s sum

Have a great day!

On the direction of the cross product of vectors

One of my math professors always told me:

Understand the concept and not the definition

A lot of times I have fallen into this pitfall where I seem to completely understand how to methodically do something without actually comprehending what it means.

And only after several years after I first encountered the notion of cross products did I actually understand what they really meant. When I did, it was purely ecstatic!

Why on earth is the direction of cross product orthogonal ? Like seriously…

I mean this is one of the burning questions regarding the cross product and yet for some reason, textbooks don’t get to the bottom of this. One way to think about this is :

It is modeling a real life scenario!!

The scenario being :

When you try to twist a screw (clockwise screws being the convention) inside a block in the clockwise direction like so, the nail moves down and vice versa.

i.e When you move from the screw from u to v, then the direction of the cross product denotes the direction the screw will move..

That’s why the direction of the cross product is orthogonal. It’s really that simple!

Another perspective

Now that you get a physical feel for the direction of the cross product, there is another way of looking at the direction too:

Displacement is a vector. Velocity is a vector. Acceleration is a vector. As you might expect, angular displacement, angular velocity, and angular acceleration are all vectors, too.

But which way do they point ?

Let’s take a rolling tire. The velocity vector of every point in the tire is pointed in every other direction.

BUT every point on a rolling tire has to have the same angular velocity – Magnitude and Direction.

How can we possibly assign a direction to the angular velocity ?

Well, the only way to ensure that the direction of the angular velocity is the same for every point is to make the direction of the angular velocity perpendicular to the plane of the tire.

Problem solved!

Crazy Looking Bamboo Tower Creates 25 Gallons of Drinking Water Per Day From Thin air

This crazy looking tower creates 25 gallons of drinking water per day from thin air. It’s basically an atmospheric water collector which gathers dew from the air.

“…The 9 m tall bamboo framework has a special fabric hanging inside capable to collect potable water from the air by condensation…”

It’s called the WarkaWater:

“…The name ‘WarkaWater’ comes from the Warka Tree, a giant wild fig tree native to Ethiopia, traditionally used for public gatherings and school education. The Warka Tree is an archetype of the Biennale theme ‘Common Ground’…”

The simple and practical, yet elegant design powers out ahead of any of the commercial atmospheric water generators on the market which cost thousands more to build than this.

This is a wonderful water generation idea, that’s inexpensive, and actually beautiful to look at.

Water is life, and being designed after a tree. This is a real Tree of Life.