Ceramics: Aluminum Nitride

Alloys: Wood’s Metal

Also known as Lipowtiz’s alloy as well as the commercial names of Cerrobend, Bendalloy, Pewtalloy, and MCP 158 among others, Wood’s metal is a bismuth alloy consisting of 50% bismuth, 26.67% lead, 13.33% tin, and 10% cadmium by weight. Named for the man who invented it, a Barnabas Wood, Wood’s metal was discovered/created by him in 1860.

Wood’s metal is both a eutectic and a fusible alloy, with a low melting temperature of approximately 70 °C (158 °F). While none of its individual components have a melting temperature of less than 200 °C, a eutectic alloy can be considered as a pure (homogeneous) substance and always has a sharp melting point. If the elements in a eutectic compound or alloy are not as tightly bound as they would be in the pure elements, this leads to a lower melting point. (Eutectic substances can have higher melting points, if its components bind tightly to themselves.)

Useful as a low-temperature solder or casting metal, Wood’s metal is also used as valves in fire sprinkler systems. Thanks to its low melting temperature, Wood’s metal melts in the case of a fire and thanks to the bismuth it is made from, the alloy also shrinks when it melts (bismuth, like water ice, is one of the few substances to do so) which is the key to setting off the sprinkler system. Wood’s metal is also often used as a filler when bending thin walled metal tubes: the filler prevents the tube from collapsing, then can be easily removed by heating and melting the Wood’s metal. Other applications include treating antiques, as a heat transfer medium in hot baths, and in making custom shaped apertures and blocks for medical radiation treatment.

With the addition of both lead and cadmium, however, Wood’s metal is considered to be a toxic alloy. Contact with bare skin is thought to be harmful, especially once the alloy has melted, and vapors from cadmium containing alloys are also quite dangerous and can result in cadmium poisoning. A non-toxic alternative to Wood’s metal is Field’s metal, composed of bismuth, tin, and indium.

Sources: ( 1 - image 4 ) ( 2 - image 2 ) ( 3 ) ( 4 )

Image sources: ( 1 ) ( 3 )

If you trace the orbits of Earth and Venus over 8 years, this is the pattern that emerges

PERIODIC SPONGE SURFACES AND UNIFORM SPONGE POLYHEDRA IN NATURE AND IN THE REALM OF THE THEORETICALLY IMAGINABLE

By Michael Burt- Prof emeritus, Technion, I.I.T. Haifa Israel

The diversity of shapes and forms which meets the eye is overwhelming. They shape our environment: physical, mental, intellectual. Theirs is a dynamic milieu; time induced transformation, flowing with the change of light, with the relative movement to the eye, with physical and biological transformation and the evolutionary development of the perceiving mind. “Our study of natural form “the essence of morphology”, is part of that wider science of form which deals with the forms assumed by nature under all aspects and conditions, and in a still wider sense, with forms which are theoretically imaginable…..(On Growth and Form – D'Arcy Thompson), “Theoretically” to imply that we are dealing with causal- rational forms. “It is the business of logic to invent purely artificial structures of elements and relations. Sometimes one of these structures is close enough to a real situation to be allowed to represent it. And then, because the logic is so tightly drawn, we gain insight into the reality which was previously withheld from us” (C. Alexander). A particular interest should be focused on those structures which are shaped like solids or containers, with continuous two-manifold enveloping surfaces, enclosing a volume of space and thus subdividing the entire space into two complementary sub-spaces, sometimes referred to as interior and exterior, although telling which is which, is a relativistic notion. On each of these envelopes, topologically speaking, an infinite number of different maps composed of polygonal regions (faces), which are bounded by sets of edge segments and vertices, could be drawn, to represent what we call polyhedra, or polyhedral envelopes. We come to know them by various names and notations, evolving through many historical cultures up to our present times; each representing an individual figure-polyhedron, or a family, a group, a class or a domain; convex-finite, Platonic and Archimedean polyhedra; pyramids, prisms; anti-prisms; star polyhedra; deltahedra; zonohedra; saddle polyhedra, dihedral, polydigonal, toroidal, sponge like, finite and infinite polyhedra; regular, uniform, quasi-regular, and so forth; all inscribable in our 3-dimensional space. It is these structures and their extended derivatives which shape our physical-natural or artificial man-conceived environment and provide for our mental pictures of its architecture. The number of forms which had acquired a name or a specific notation through the ages is amounting to infinity, although the number of those which comprise our day to day formal vocabulary and design imagery is extremely (and regretfully) limited by comparison, even amongst designers and architects, whose profession, by definition, compels them to manipulate and articulate forms and space. Here it is right to observe that name-giving is part of the creative and generative process. The number of polyhedral forms which did not receive, as yet a proper name or a notation is also infinite. Infinite is also the number of potentially existing and possible imaginary periodic forms, not envisaged yet. Conspicuous are those relating to sponge-like labyrinthian, polyhedral, space dividing surfaces, which until quite recently were not even considered as a research topic. The interest in these forms has been prompted by our growing awareness of their abundance in nature and their importance, not only in describing micro and macro-physical and biological phenomena, but also in coping with morphological complexity and nature of our built environment and its emerging new architecture and the order and formal character of our living spaces, on either the building or the urban scale. Nature is saturated with sponge structures on every possible scale of physical-biological reality. The term was first adopted in biology: “Sponge: any member of the phylum Porifera, sessile aquatic animals, with single cavity in the body, with numerous pores. The fibrous skeleton of such an animal, remarkable for its power of sucking up water”. (Wordsworth dictionary). the entire study here

© Michael Burt- Prof emeritus, Technion, I.I.T. Haifa Israel

You might be an engineer if you know how long a zeptosecond is. (It's a trillionth of a billionth of a second!) http://ow.ly/uUUb30caXrH 

Google’s Wireless ‘Pixel Buds’ Headphones Can Translate 40 Languages in Real Time

Solar System: Things to Know This Week

Reaching out into space yields benefits on Earth. Many of these have practical applications — but there’s something more than that. Call it inspiration, perhaps, what photographer Ansel Adams referred to as nature’s “endless prospect of magic and wonder.“ 

Our ongoing exploration of the solar system has yielded more than a few magical images. Why not keep some of them close by to inspire your own explorations? This week, we offer 10 planetary photos suitable for wallpapers on your desktop or phone. Find many more in our galleries. These images were the result of audacious expeditions into deep space; as author Edward Abbey said, "May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view.”

1. Martian Selfie

This self-portrait of NASA’s Curiosity Mars rover shows the robotic geologist in the “Murray Buttes” area on lower Mount Sharp. Key features on the skyline of this panorama are the dark mesa called “M12” to the left of the rover’s mast and pale, upper Mount Sharp to the right of the mast. The top of M12 stands about 23 feet (7 meters) above the base of the sloping piles of rocks just behind Curiosity. The scene combines approximately 60 images taken by the Mars Hand Lens Imager, or MAHLI, camera at the end of the rover’s robotic arm. Most of the component images were taken on September 17, 2016.

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2. The Colors of Pluto

NASA’s New Horizons spacecraft captured this high-resolution, enhanced color view of Pluto on July 14, 2015. The image combines blue, red and infrared images taken by the Ralph/Multispectral Visual Imaging Camera (MVIC). Pluto’s surface sports a remarkable range of subtle colors, enhanced in this view to a rainbow of pale blues, yellows, oranges, and deep reds. Many landforms have their own distinct colors, telling a complex geological and climatological story that scientists have only just begun to decode.

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3. The Day the Earth Smiled

On July 19, 2013, in an event celebrated the world over, our Cassini spacecraft slipped into Saturn’s shadow and turned to image the planet, seven of its moons, its inner rings — and, in the background, our home planet, Earth. This mosaic is special as it marks the third time our home planet was imaged from the outer solar system; the second time it was imaged by Cassini from Saturn’s orbit, the first time ever that inhabitants of Earth were made aware in advance that their photo would be taken from such a great distance.

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4. Looking Back

Before leaving the Pluto system forever, New Horizons turned back to see Pluto backlit by the sun. The small world’s haze layer shows its blue color in this picture. The high-altitude haze is thought to be similar in nature to that seen at Saturn’s moon Titan. The source of both hazes likely involves sunlight-initiated chemical reactions of nitrogen and methane, leading to relatively small, soot-like particles called tholins. This image was generated by combining information from blue, red and near-infrared images to closely replicate the color a human eye would perceive.

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5. Catching Its Own Tail

A huge storm churning through the atmosphere in Saturn’s northern hemisphere overtakes itself as it encircles the planet in this true-color view from Cassini. This picture, captured on February 25, 2011, was taken about 12 weeks after the storm began, and the clouds by this time had formed a tail that wrapped around the planet. The storm is a prodigious source of radio noise, which comes from lightning deep within the planet’s atmosphere.

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6. The Great Red Spot

Another massive storm, this time on Jupiter, as seen in this dramatic close-up by Voyager 1 in 1979. The Great Red Spot is much larger than the entire Earth.

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7. More Stormy Weather

Jupiter is still just as stormy today, as seen in this recent view from NASA’s Juno spacecraft, when it soared directly over Jupiter’s south pole on February 2, 2017, from an altitude of about 62,800 miles (101,000 kilometers) above the cloud tops. From this unique vantage point we see the terminator (where day meets night) cutting across the Jovian south polar region’s restless, marbled atmosphere with the south pole itself approximately in the center of that border. This image was processed by citizen scientist John Landino. This enhanced color version highlights the bright high clouds and numerous meandering oval storms.

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8. X-Ray Vision

X-rays stream off the sun in this image showing observations from by our Nuclear Spectroscopic Telescope Array, or NuSTAR, overlaid on a picture taken by our Solar Dynamics Observatory (SDO). The NuSTAR data, seen in green and blue, reveal solar high-energy emission. The high-energy X-rays come from gas heated to above 3 million degrees. The red channel represents ultraviolet light captured by SDO, and shows the presence of lower-temperature material in the solar atmosphere at 1 million degrees.

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9. One Space Robot Photographs Another

This image from NASA’s Mars Reconnaissance Orbiter shows Victoria crater, near the equator of Mars. The crater is approximately half a mile (800 meters) in diameter. It has a distinctive scalloped shape to its rim, caused by erosion and downhill movement of crater wall material. Since January 2004, the Mars Exploration Rover Opportunity has been operating in the region where Victoria crater is found. Five days before this image was taken in October 2006, Opportunity arrived at the rim of the crater after a drive of more than over 5 miles (9 kilometers). The rover can be seen in this image, as a dot at roughly the “ten o'clock” position along the rim of the crater. (You can zoom in on the full-resolution version here.)

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10. Night Lights

Last, but far from least, is this remarkable new view of our home planet. Last week, we released new global maps of Earth at night, providing the clearest yet composite view of the patterns of human settlement across our planet. This composite image, one of three new full-hemisphere views, provides a view of the Americas at night from the NASA-NOAA Suomi-NPP satellite. The clouds and sun glint — added here for aesthetic effect — are derived from MODIS instrument land surface and cloud cover products.

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Americas at night

Discover more lists of 10 things to know about our solar system HERE.

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

IMPOSSIBLE! Right? You may have heard “the interior angles of a triangle always add up to 180 degrees”. This is not always true. Check out the second image, it shows a triangle with 3 right angles for a total of 270 degrees! 

It is true in flat Euclidean geometry (the geometry you probably learned in school) however. But there are so many other geometries out there! You may be thinking, are other geometries real though? A mathematician would argue they are just as real as the typical flat geometry you know and love (or hate). These alternative geometries can be practically useful too!

The images above show triangles in spherical geometry. Those aren’t triangles though! Oh but they are! A triangle is just a polygon enclosed by three lines. Looks like it fits the criteria. Wait but those aren’t lines, they are curved! Ah yes. I argue that these are, for all intents and purposes, just as good as lines. We need to ask: What is a line? A line is so basic to us we may not know how to describe it. I offer this definition: A line is the shortest path between 2 points. The 3 curves that make the triangle above are in fact the shortest paths from one vertex to the other on the surface of the sphere (they just so happen to be on circumferences of the sphere, which are often referred to as great circles). So it may be more useful to think of lines, in general, as length minimizing curves. In conclusion, we would consider the shape above to be a triangle as it is enclosed by 3 length minimizing curves on a surface.

Spherical geometry can be very useful; think about the Earth. To reduce travel time, airplanes would want to travel along great circles as they are the shortest paths from one place to another. Additionally, this type of thinking (rethinking straight lines as length minimizing curves) is central to Albert Einstein’s general theory of relativity.

read more at http://staffrm.io/@missnorledge/35H6cS1T52

Thought this was important to post.

Does one of these LEGO men look bigger than the other? They’re actually the exact same size, but are in an Ames room - a false-perspective illusion room that tricks your brain into thinking things are smaller, or larger, than they really are.

You can make one of these models to try this for yourself. Download our free template from here. And it even works in full size, if you can make one large enough!

Science Fact Friday: Bird lungs! Just like every other part of a bird, they’re weird.

This gif shows the path of a single breath, but the circuit holds 2 breaths at a time. So when the bird inhales, the just-inhaled breath goes through Inhalation 1 while the previous breath goes through Inhalation 2. Rinse, repeat. Thus, the lungs are constantly receiving oxygen - in mammals, our oxygen content dips slightly between inhalations because there’s no fresh air coming in. We also don’t empty 100% of our lung volume so some air is “stale” even during an inhalation.

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