Crows And Ravens Are Pretty Well Known For Their Incredible Smarts. In This Experiment, Psychologists

18 Science Facts We Didn't Know at The Start of 2017

We've learned so much already.

1. Lungs don’t just facilitate respiration - they also make blood. Mammalian lungs produce more than 10 million platelets (tiny blood cells) per hour, which equates to the majority of platelets circulating the body.

2. It is mathematically possible to build an actual time machine - what’s holding us back is finding materials that can physically bend the fabric of space-time.

3. Siberia has a colossal crater called the ‘doorway to the underworld’, and its permafrost is melting so fast, ancient forests are being exposed for the first time in 200,000 years.

4. The world’s first semi-synthetic organisms are living among us - scientists have given rise to new lifeforms using an expanded, six-letter genetic code.

5. Vantablack - the blackest material known to science - now comes in a handy ‘spray-on’ form and it’s the weirdest thing we’ve seen so far this year.

6. It’s official: time crystals are a new state of matter, and we now have an actual blueprint to create these “impossible” objects at will.

7. A brand new human organ has been classified, and it’s been hiding in plain sight this whole time. Everyone, meet your mesentery.

8. Carl Sagan was freakishly good at predicting the future - his disturbingly accurate description of a world where pseudoscience and scientific illiteracy reigns gave us all moment for pause.

9. A single giant neuron that wraps around the entire circumference of a mouse’s brain has been identified, and it appears to be linked to mammalian consciousness.

10. The world’s rarest and most ancient dog isn’t extinct after all - in fact, the outrageously handsome New Guinea highland wild dog appears to be thriving.

11. Your appendix might not be the useless evolutionary byproduct after all. Unlike your wisdom teeth, your appendix might actually be serving an important biological function - and one that our species isn’t ready to give up just yet.

12. After 130 years, we might have to completely redraw the dinosaur family tree, thanks to a previously unimportant cat-sized fossil from Scotland.

13. Polycystic ovary syndrome might actually start in the brain, not the ovaries.

14. Earth appears to have a whole new continent called Zealandia, which would wreak havoc on all those textbooks and atlases we’ve got lying around.

15. Humans have had a bigger impact on Earth’s geology than the infamous Great Oxidation Event 2.3 billion years ago, and now scientists are calling for a new geological epoch - the Anthropocene - to be officially recognised.

16. Turns out, narwhals - the precious unicorns of the sea - use their horns for hunting. But not how you’d think.

17. Human activity has literally changed the space surrounding our planet - decades of Very Low Frequency (VLF) radio communications have accidentally formed a protective, human-made bubble around Earth.

18. Farmers routinely feed red Skittles to their cattle, because it’s a cheap alternative to corn. ¯\_(ツ)_/¯

Here’s every total solar eclipse happening in your lifetime. Is this year your best chance?

On Aug. 21, a total solar eclipse will be visible from the continental United States. It’ll be the first to traverse coast to coast in nearly a century. Learn more about past and future eclipses: See full graphic.

It’s #MoleDay! Here’s an up-to-date version of my mole explainer: https://ift.tt/2D1ucqz https://ift.tt/2N8Vcaf

Composites: Papercrete

Composites are materials composed of other materials in combination, often with a matrix that binds together fibers of some kind. Papercrete gets its name from its components, paper and concrete, though it is technically composed of cement, not concrete. In papercrete, a composite of paper and cement, the cement makes up the binding matrix that holds the paper fibers together.

Paper is composed of a natural polymer, cellulose, the structure of which can be seen in the bottom image above and fibers of which can be seen in the top left and middle right images. The fibers get coated with cement, often Portland cement, and lend strength to the new material that could not be found in the cement alone. (Paper is not only made of cellulose, but it is a key component which makes papercrete possible. Aside from paper and cement, papercrete is also made with water and some form of sand or earth - other materials can be used as well, just like in concrete).

The material resulting from this mixture, papercrete, has excellent sound absorption, is flame and fungus retardant as well as bug and rodent repellent, and is relatively light. More flexible then rock or regular concrete, papercrete is useful in earthquake prone areas. Though not the best load-bearing material, papercrete is a great insulator. Like any composite however, the exact formula used to produce the material can alter the properties significantly. Adding sand or glass strengthens papercrete and makes it more flame retardant, but also increases its weight. 

One of the beneficial things about papercrete is that almost any paper can be used to create it - cardboard, magazine paper, junk mail, newspaper, and other forms. Some work better than others but almost all can be used. Using waste papers such as these prevents them from entering landfills and allows paper to be recycled in a different way. 

Downsides of papercrete include its lower strength and durability, as well as the fact that - as of now - there is no code or standardization to its manufacture or use, limiting the projects it can be used in. A fair amount of papercrete is made by individuals working on ‘do it yourself’ projects.

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

Image sources: (Middle left)

We started looking at fluctuating loads last time - that is, loads that feature some combination of non-zero mean and alternating stresses - and how to account for them using a Goodman diagram. Let’s re-examine the bracket design problem we did earlier. This time, instead of a fully-reversed load, we’ll assume a fluctuating load with a mean force of 200 lbs, a minimum force of 50 lbs, and a maximum force of 350 lbs. We’ll say the dimensions of the bracket are those we calculated earlier that could handle the fully reversed load. (Problem adapted from Machine Design: An Integrated Approach, 4th Ed., by Robert L. Norton.)

Most of the calculations we did earlier will still hold. We won’t need to recalculate the endurance limit or stress concentration factors. The only new things we need to do are calculate the mean and alternating stresses and the new safety factors.

First step is to calculate the mean and alternating force.

From here, we get the mean and alternating moment.

We’re dealing with a situation of simple bending, so we can calculate mean and alternating stress using the basic bending stress equation.

The geometry of the part hasn’t changed, so we’ll apply the same stress concentration factors that we used before.

Great. We’ve got our new stresses. Now we need to figure out safety factors. As we mentioned earlier, this is now a slightly more complicated proposition. Which safety factor is appropriate will depend on how the alternating and mean stress behave in relation to each other. The possible failure states are shown as points A, B, C, and D on the Goodman diagram for this situation.

We’ll step through all the possible situations one by one using the new stresses we calculated and the endurance limit we got earlier.

Case 1: Constant alternating stress, variable mean stress.

Case 2: Variable alternating stress, constant mean stress.

Case 3: Alternating and mean stress are proportional to each other.

Case 4: Alternating and mean stress vary independently.

We take the worse case, with the failure state F being as close as possible to the current stress situation.

Our design will survive all four cases. Note that Case 4 is always the most conservative case - if you don’t know what your stresses are going to do, this is the one to go with.

You’ll wonder how you ever lived without this charming social robot

Hackaday Useful Tools Links

So I am an avid reader of Hackaday for a long time now and they have been putting out a lot of great introductions to tools and processes to get makers up to speed on the resources that are available.  This is just a splattering of links that I have found lately that you guys might be interested in.

DC Motors

Lessons in Small Scale Manufacturing

Grinding Gears: Figuring out gear ratios

Tools of the trade: Injection Molding

Are todays engineers worse?

How to nail a technical presentation

Tools of the trade: Vacuum Forming

The Art and Science of Bending Sheetmetal

A how-to of designing, fab, and assembly with structural framing systems (t slot)

Machine learning foundations

A machine shop in a box

How to: Cold resin casting

Join the GUI generation: Qtcreator

Do you guys have any other great resources that you’d like to share and/or are you enjoying this type of content?

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 )

Physical Science...In Space!

Each month, we highlight a different research topic on the International Space Station. In May, our focus is physical science.

The space station is a laboratory unlike any on Earth; on-board, we can control gravity as a variable and even remove it entirely from the equation. Removing gravity reveals fundamental aspects of physics hidden by force-dependent phenomena such as buoyancy-driven convection and sedimentation.

Gravity often masks or distorts subtle forces such as surface tension and diffusion; on space station, these forces have been harnessed for a wide variety of physical science applications (combustion, fluids, colloids, surface wetting, boiling, convection, materials processing, etc).

Other examples of observations in space include boiling in which bubbles do not rise, colloidal systems containing crystalline structures unlike any seen on Earth and spherical flames burning around fuel droplets. Also observed was a uniform dispersion of tin particles in a liquid melt, instead of rising to the top as would happen in Earth’s gravity. 

So what? By understanding the fundamentals of combustion and surface tension, we may make more efficient combustion engines; better portable medical diagnostics; stronger, lighter alloys; medicines with longer shelf-life, and buildings that are more resistant to earthquakes.

Findings from physical science research on station may improve the understanding of material properties. This information could potentially revolutionize development of new and improved products for use in everything from automobiles to airplanes to spacecraft.

For more information on space station research, follow @ISS_Research on Twitter!

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Students fortify concrete by adding recycled plastic

Adding bits of irradiated plastic water bottles could cut cement industry’s carbon emissions

Discarded plastic bottles could one day be used to build stronger, more flexible concrete structures, from sidewalks and street barriers, to buildings and bridges, according to a new study.

MIT undergraduate students have found that, by exposing plastic flakes to small, harmless doses of gamma radiation, then pulverizing the flakes into a fine powder, they can mix the plastic with cement paste to produce concrete that is up to 20 percent stronger than conventional concrete.

Concrete is, after water, the second most widely used material on the planet. The manufacturing of concrete generates about 4.5 percent of the world’s human-induced carbon dioxide emissions. Replacing even a small portion of concrete with irradiated plastic could thus help reduce the cement industry’s global carbon footprint.

Reusing plastics as concrete additives could also redirect old water and soda bottles, the bulk of which would otherwise end up in a landfill.

Read more.