Looping Thunderstorm Gifs By Mike Hollingshead

Major types of Engines

Straight In-line

This is the type of engine that you find in your quotidian car. Nothing fancy, just all pistons arranged parallel along the vertical direction.

V in-line

Now, this is the sort of the engine that you find on sports cars like the Ferrari. When you hear sports enthusiasts go ‘ Whoa, that’s a V-12! ‘ - it just means that the engine has a V-type arrangement with 12 cylinders.

V +  Inline = V-inline

Commonly referred to as the VR engine.

The name VR6 comes from a combination of V engine (German: V-Motor), and the German word “Reihenmotor” (meaning “inline engine” or “straight engine”)

Volkswagen’s VR6 engines, and the later VR5 variants, are a family of internal combustion engines, characterized by a narrow-angle (10.5° or 15°) V engine configuration.

                    a: straight engine, b: V engine, c: VR engine

W engine

A W engine is a type of reciprocating engine ( again created by Volkswagen) arranged with its cylinders in a configuration in which the cylinder banks resemble the letter W, in the same way those of a V engine resemble the letter V.

Bugatti Veyron’s W16 engine

A W16 engine is used on the Bugatti Veyron. That’s 16 cylinders!

Flat Engine

Flat engines offer several advantages for motorcycles, namely: a low centre of gravity, smoothness, suitability for shaft drive, and (if air-cooled) excellent cooling of the cylinders. You can find them on aircrafts as well

Radial Engine (aka the dancing starfish)

They were used mostly in small aircraft for the propeller

The big advantage of radials was their large frontal area, which meant they could be air cooled, meaning less maintenance, failures, and of course a lower cost of initial purchase and maintenance.

Wankel Engine

This engine has only 3 moving parts and can make a lot of power.However, they are pretty inefficient, the last car to use this was a Mazda RX-8.

Axial Engine

The axial engine is a very interesting design. But they are not widely used because they are just hard to make and running these things at high RPM’s  is a challenge.

Duke engines are equipped with this type.

Jet engine

Commonly jet engines refer to the engines that are found on, well Jets!

Suck,squeeze,bang and blow

Air is sucked in through the front and  squeezed. A controlled explosion follows and the exhaust is blown out through the back

But, Jet engines also include the engines that are found on rockets, hybrids and water-jets. And their mode of operation is different than the one mentioned above.

Pretty cool eh?

Have a great day!

PC: Howstuffworks, Duke, MichaelFrey, Azure.km

** There is also the Stirling Engine. It’s amazing and a topic for an another post. But if you are interested do check out more about it here.

EDIT :  Had forgotten about the VR and the W-engines. My bad! Thanks for pointing it out.:D.

EDIT2: The suck squeeze bang and blow illustration was incorrect. Ergo, changed that.

Chances of hypersonic travel heat up with new materials discovery

Researchers at The University of Manchester in collaboration with Central South University (CSU), China, have created a new kind of ceramic coating that could revolutionise hypersonic travel for air, space and defense purposes.

Hypersonic travel means moving at Mach five or above, which is at least five times faster than the speed of sound. When moving at such velocity the heat generated by air and gas in the atmosphere is extremely hot and can have a serious impact on an aircraft or projectile’s structural integrity. That is because he temperatures hitting the aircraft can reach anywhere from 2,000 to 3,000 °C.

The structural problems are primarily caused by processes called oxidation and ablation. This is the when extremely hot air and gas remove surface layers from the metallic materials of the aircraft or object travelling at such high speeds. To combat the problem materials called ultra-high temperature ceramics (UHTCs) are needed in aero-engines and hypersonic vehicles such as rockets, re-entry spacecraft and defence projectiles.

But, at present, even conventional UHTCs can’t currently satisfy the associated ablation requirements of travelling at such extreme speeds and temperatures. However, the researchers at The University of Manchester’s and the Royce Institute, in collaboration with the Central South University of China, have designed and fabricated a new carbide coating that is vastly superior in resisting temperatures up to 3,000 °C, when compared to existing UHTCs.

Why most metals are silver (but copper and gold aren’t)

If we want to understand what gives a metal its color we first need to understand a little bit about the definition of a metal. Metals are materials that experience metallic bonding - wherein the atoms are so close that there is a veritable “sea of electrons” in the substance. (This is also what makes metals conductors, but that’s another story). Basically each atom donates an electron or two that is free to flow throughout the material, unattached to any particular nucleus. 

This proximity leads to an overlap in the allowed energy levels of electrons (shown in the lower left hand image above); basically the higher empty electronic levels are so close to the uppermost filled levels (also called the Fermi level) that they form an essentially continuous band of allowed energies. 

Now, backtracking a little bit, color in a substance is caused when a material doesn’t absorb a particular wavelength of light. Because of the empty energy levels mentioned above, metals generally can absorb all wavelengths of light in the visible spectrum. This implies that a metal should look black, except that the excited electron can immediately fall back to the state that it came from, emitting exactly the same energy, causing a flat piece of metal to appear reflective. Thus, the reason why most metals are silver. (Also, the flatter a metal, the more reflective, thanks to diffuse vs. specular reflection).

For a few select metals, like copper and gold, the absorption and emission of photons are noticeably dependent on wavelength across the visible part of the spectrum. The graph in the lower right image above shows the reflectance of aluminum, silver, and gold, including wavelengths in the infrared and ultraviolet. Aluminum is pretty reflective overall, and silver is highly reflective in the visible region (about 400 to 700 nm), but gold clearly absorbs wavelengths about 500 nm or below. Thus, it most strongly reflects yellow, giving it its characteristic appearance. 

Sources: (first image), 2 (second image), 3 (third image), 4

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.

Bones are interesting because you can sometimes read the patterns of wear and growth like reading a book.

I got a couple of stray cat skulls, and this guy has a pretty interesting story to him.

INSTAGRAM / FACEBOOK / ETSY

A portal to another universe ?

That my dear friends is a CT scan machine. Stripped off all the body parts, you can see clearly see what goes on inside.

A computerized tomography (CT) or computerized axial tomography (CAT) scan combines data from several X-rays to produce a detailed image of structures inside the body.

                                            CT scan of Brain

Pretty cool, don’t you think ?

Extras

Difference between MRI and CT scan

Why dont you spin the patient instead ? - Awesome reddit thread

Better quality gifs : here

Source Video: Micheal Jonnson

Researchers build first deployable, walking, soft robot

Researchers have built the first robot made of soft, deployable materials that is capable of moving itself without the use of motors or any additional mechanical components. The robot “walks” when an electric current is applied to shape-memory alloy wires embedded in its frame: the current heats the wires, causing the robot’s flexible segments to contract and bend. Sequentially controlling the current to various segments in different ways results in different walking gaits.

The researchers expect that the robot’s ability to be easily deployed, along with its low mass, low cost, load-bearing ability, compact size, and ability to be reconfigured into different forms may make it useful for applications such as space missions, seabed exploration, and household objects.

The scientists, Wei Wang et al., at Seoul National University and Sungkyunkwan University, have published a paper on the new robot and other types of deployable structures that can be built using the same method in a recent issue of Materials Horizons.

“The main advantage of this modular robot is robustness in various environments due to lack of mechanical systems such as motors and gears,” coauthor Sung-Hoon Ahn at Seoul National University told Phys.org. “Thus, problems facing motor-based robots, such as sealing and lubrication of mechanical systems in water or space environments, are not a problem for the smart actuator.”

Read more.

Alloys: 300 series Stainless Steel

When chromium is added to steel in sufficient amounts, it reacts with oxygen on the surface of the metal, creating a thin transparent layer that prevents further oxidation such as rusting. The layer is even self-healing, when damaged by scratches or wear. Steels that have over ten percent chromium added are classified as stainless steels, with high strength and toughness, in addition to the corrosion resistance - and there are hundreds of varieties of stainless steel.

As such, these alloys are divided into types, or series, often defined by their compositions or the methods of forming and working them. The 300 series of stainless steels are austenitic stainless steels, with an austenitic or face-centered cubic crystal structure. They contain anywhere from about 15-30% chromium, as well as up to about 20% nickel and other elements such as molybdenum. The nickel stabilizes the austenitic structure and increases ductility as well as high temperature strength and corrosion resistance. 

The 300 series alloys are non-magnetic in the annealed condition, though they can become slightly magnetic when cold worked, depending on the nickel content. Comparatively, these steels have high ductility, low yield stress, and high tensile strengths.

Commonly used 300 series stainless steels include 301, 302, 304, and 316, as well as the low carbon variations of these types, designated with an L, such as 316L. 304 stainless steel is also often called 18/8 stainless steel, given that it has 18% Cr and 8% Ni, or A2 stainless. The 316 grade is also know as A4, or marine grade stainless. 

In the photos above, the Gateway Arch in St. Louis is clad in type 304 SS, while the Chrysler Building in New York is clad with Nirosta stainless steel, a form of type 302.  

Sources: ( 1 ) ( 2 ) ( 3 ) ( 4 - images 1 and 2 ) ( 5 - image 3 )

In mathematics there is a concept known as ‘Conformal Mapping’ which allows you convert a given shape to a completely different one by making a transformation.

In the joukowski transform you take all the points on a circle and apply the following transform:

And the resulting transformed points resemble an aerofoil shape. Pretty cool huh ?

** Conformal mappings are a really cool topic in complex analysis but also equally extensive. If you want to know more about them click here

Concrete vs. Cement

Concrete and cement are (mostly) two different materials. Why mostly? Because concrete is made using cement. Though cement can (technically) be used on its own, concrete cannot be made without first making cement.

Classified as a ceramic, cement starts as a powder, a mixture of limestone and other minerals, which is heated and mixed with gypsum to form what we know of as cement. Still a powder in this form, once water is added and mixed the cement then hardens. 

Portland cement, probably the most well known and commonly used cement, is classified as a hydraulic cement. This essentially means that once water has been added the chemical reaction, called hydration, that hardens the cement is not dependent on how much water is added. Hydraulic cements can harden underwater and remain strong even in wet conditions. As a side note, Portland cement is not a brand name, but a particular type of cement.

On the other hand, concrete is composed of cement, aggregate, and water, and is thus classified as a composite. Composites are defined as consisting of a matrix or binder that has a reinforcement within it. In the case of concrete, the cement water mixture is the matrix in which the reinforcement, or aggregate exists. 

The aggregate is typically comprised of stones, rocks, and sand and its addition increases the durability of the concrete. The amount of the aggregate or the size of the aggregate added can also effect the water-to-cement ratio required to harden the material, strengthening the final product. The hardening process continues for years, meaning that concrete only gets stronger with age.

Though most concretes are lime-based, asphalt concrete uses asphalt as the cement material and polymer concretes also exist. Another common type of concrete is reinforced concrete, in which rebar, or reinforcing bars, are embedded within to add to the strength of the concrete.

Sources: ( 1 ) ( 2 ) ( 3 ) ( 4 ) ( 5 )