Atom Smith Dick Siegel invented technique of teasing atoms into tiny clusters transforming the ordinary stuff of everyday life into extraordinary materials of tomorrow. Dick Siegel, at RPI in Troy NY. Learned how to transform substances from ordinary to extraordinary. Small metal disk of pure copper. A pill size piece of titania, a common ceramic. At one time the sample was shaped like a miniature soup can, These nonmetallic substances are usually stiff that they respond to pressure by fracturing into a thousand pieces. Drop a tin cup on the floor, and it will flex a little bit and bounce back into shape, small dents notwithstanding. Siegel brings out a disk of yttria, another ceramic, a white and opaque. This disk, is a ghost of its former self. Complete transparent. How does copper or yttria step into a phone booth and emerge with superpowers like ultrastrength or transparency? Siegel has developed a new way to manipulate matter on an atomic level. The traditional route is to modify materials is to use chemistry. Adding a carbon to iron creates a strong metal : steel. A few drops of the right chemical can turn a white liquid clear. Instead of changing the chemical compositions, Siegel alters the way in which the atoms organize themselves. A normal piece of copper, is a patchwork quilt, with no two patches the same shape or size. Each of the building blocks / grains is a single crystal in which the atoms are stacked in an orderly fashion. The grains themselves are disorderly. The attributes of that piece of copper - from strength and flexibility to color and electrical conductivity - depend on two things: the properties of the individual grains, and the relationships and interactions between the grains. Copper is a good conductor because electrons (carriers of electric current) can move freely inside the grains and can jump easily from one grain to another. Take copper and run it through Siegels forge . In place of the patchwork, there is a smooth and featureless nothingness. Siegel's copper has a patchwork structure very similar to that of the standard sample, but the individual grains are 10000 times smaller. A trillion grains of the superhard copper could fit inside one average size grain of the normal stuff. The same grains account for Siegel's mashable titania and transparent yttria. Siegels forge can produce materials with grain sizes 1/1000 the common grain size. Yttria produced grain sizes too small to scatter light. Lightwaves ignore features smaller than 1/4 of a wavelength 100nanometers. Hardness or electrical and magnetic properties, the critical lengths range from 10 - 100 nanometers. By making materials with grain sizes smaller than this. Siegel can get them to behave in novel and unusual ways. Nanocrystalline materials continue to change the grains get smaller and smaller. If the copper grain size is 50nanom eters the copper is twice as hard as conventional copper. Grains 1/1000 times larger. Grain size down to 25nanometers and copper is 3 times as hard. 15nanometers 4x , 6nanometers, 5x harder. Controlling grain size and structure is a big business. Steel mills use rolling presses that squeeze sheets of steel to break grains into smaller pieces - yielding tougher steel. The computer chip industry depends on making the grains as big as possible. They are built on single crystals of silicon several inches across. New methods to create/control nanometer scale grains, grains 1/1000 times smaller than those in modern steels and ceramics. The device of choice is the highspeed ball mill. You put a powder of copper into the machine's steel canister add several tungsten carbide balls and shake violently , tossing the balls around and crushing the powder between them and the steel sides. 20 hours later, the grains of pulverized powder are reduced to fragments 1/100 their previous size. The alternative to breaking the grains down is to build them up from scratch, atom by atom. In theory, this makes it possible to create grains of virtually any size. It's not hard to assemble atoms into grains or clusters. Under the right conditions, atoms will naturally congragate. A pair of atoms then a third arrives and a forth. Crystals form in this way. The challenge for Siegel and others is to stop the growth once the clusters reach the desired size and carry out this controlled growth on a massive scale. If the clusters are 10nanometers across, it will take a quadrillion - of them to make a pellet a millimeter across. Brus grows his colorful clusters in solution. He mixes 2 reagents, one containing cadmium and the other selenium, which combine to create cadmium selenium crystals. To control the sizes of the clusters, he grows them inside tiny micelles, spherical drops of water suspended in a beaker of the organic solvent heptane. The clusters can get no bigger than the micelles because the reaction that produces the cadmium selenium will not proceed in heptane. Brus adds a solution of organic molecules that are attracted to the surface of the clusters. They form an organic skin that keep the clusters at the desired size after they're removed from the confines of the micelles. Siegel has taken a different tack. A technique for creating nanometer-size grains like boiling a pot of water on a cold day in a room with a window. As water molecules steam out of the pot, they aggregate into clusters, which freeze when they reach the windowpane. Scrape these ice crystals off and you can pack them into a snowball. Siegel heats the copper in his $100,000 equipment/apparatus setup. He puts the copper in a tungsten pot (a boat) and heats the boat with an electric current, zapping the copper with a beam of high energy electrons. As the temperature rises ,, the copper atoms boil off into a chamber filled with helium gas. Collisions with the helium atoms slow the copper atoms enough so that when two of them collide they stick together instead of bouncing apart. Atom by atom, the copper "steam" condensese into clusters. The helium gas carries the clusters to a cold finger = - a cylinder cooled by liquid nitrogren to -319degrees Fahrenheit - which plays the role of the windowpane. A Teflon blade scrapes the copper clusters from the walls of the cylinder, and they fall through a funnel into a compactor, where the clusters are in turn shaped into little pellets of pure nanograin copper. By adjusting the evaporation rate of the copper, the pressure of the helium gas and how quickly the flow of helium carries the clusters to the cold finger, Siegel can control the size of the clusters. He can make clusters 6-10 nanometers wide. Why do copper and other metals get so hard when their grains get small? Metals are relatively soft because metal atoms can move past one another easily. Allowing dislocation in a grain - a structural kink - to shift around easily from place to place. Siegel likens the process to moving a heavy rug across a carpeted floor. Strengthening a metal has involved adding impurities that disrupt the normal crystalline structure and make it harder for dislocations to move. Putting carbon in iron to produce steel. Like putting a chain on the rug. Shrinking the grains hardens the metal in a different way : it makes it much more difficult for dislocations to form. Dislocations that occur near the edge of a grain are inherent unstalbe because the atoms tend to shift around in such a way that they quickly push the dislocations out of the grain, at which point they dissipate. In large grains, most dislocations are too far from the grain boundary to be eliminated in this way. Nanometer size grains are small enough that any dislocaiton is close to the edge and close to immediate elimination. The smaller the clusters, the fewer the dislocations and the harder the metal. On the other hand, decreasing grain size makes nanocrystalline ceramics easier to deform. The atoms in its grains cannot move past one another as easily as the atoms in a metal. Put too much stress on a ceramic plate and cracks will open up between the grains. The ceramic has no other way to relieve the stress than to shatter into tiny bits. Ceramics with nanometer size grains, have an alternative : individual grains can shuffle around ,sliding past one another like grains of sand in a sand pile. Siegel's ceramics pull this off because atoms at the edges of the grains can shift slightly as the grains move, filling up any gaps before cracks form. This doesn't happen with large-grain ceramics, Siegel says, because the atoms at the interfaces move very slowly ,and if the grains are large , it takes an impossibly long time for the atoms to move far enough to fill in the gaps between the grains. Even with nanometer size grains, the process is not quick. 15 hours of steady pressure at high temperatures to mash his titania soup can. Value of nanocrystalline materials. Powerful magnets might have coils of superhard copper that resist being stretched by the strong magnetic field. Since nanoscale powders of palladium have lots of surface area to suppor tchemical reactions they might serve as catalysts in the chemical industry. Siegel expects nanocrystalline semiconductors and composites. even nanoplastics. Siegel formed Nanophase Technologies corporation (phase refers to any form of matter). So far can churn out tens of tons of ceramic powder a year. Nanophase ceramics can be deformed which means the parts could in theory be pressed into shape in a die. The finished pieces would be indistinguishable from a normal ceramic, except that they would be cheaper. Nanophase iron oxide absorbs light without scattering it, so provides color but not opacity. The makeup "imparts a rich transparent color" to the skin. /*---------------------------------------------------------------------*/ Amazing All-Natural Light Machine How plants conduct photosynthesis has been one of the great mysteries of science. A team of biochemists in Glasgow has shed light on the process, with the discovery of an exceedingly pretty little molecule, carried by bacteria in a very unlovely pond. LH2 (LH2 is a molecule critical in lightharvesting device). A minuscule antenna designed to capture energy from atmospheric light and channel it into the microscopic factory where a photosynthetic cell first stores it, then uses it to manufacture substances like sugars and proteins. The molecule is 3 ten-millionths of an inch across - LH2 is a hollow cylinder, a doughnut rubber washer. LH2 ringlike outer edges and central holes face the atmosphere and down in the cell. Between them inner and outer colonnades embrace the works of LH2 - the pigment compounds that pick up and transmit light energy. These are versions of chlorophyll, and carotenoids. Chlorophylls - LH2 has more of them, 9 chlorophyll molecules circle the outer wall of the complex, The schemese real beauty. The elegant circular fretwork into which the proteins weave the chlorophylls makes those pigments adept at cathcing and transmitting light energy. The protein columns hold them in a chemical grip that helps determine what sort of light energy they pick up, and also place them in a configuration that helps them pass that energy from molecule to molecule, down into the cell's reaction center, where photosynthesis takes place. Imagine 8 LH2s each with its circle of 850 nanometer chlorophylls, suspended in the complex and glowing with stored energy. The story would end, but a larger antenna device the LH1. A holow cylinder, submicroscopic dynamo in which the energy gathered by LH1 and LH2 is put to final use. The ring of 850nanometer chlorophylls in Lh2 unit is aligned with a ring of 875 nanometer chlorophylls circline the LH1, which allows light energy to hop easily aboard LH1 from any LH2. Like an antenna dish, with the LH2 on the outer edges, the LH1 in the middle, the reaction center in the middle of that. That's where a key step in photosynthesis happens : the energy gathered by LH1 and LH2 pulls an electron out of still another chlorophyll molecules and attaches it to an "acceptor molecule" curiously, the only time anything but energy ever moves in the whole process is the moment when an electron is pulled from its donor and attached to ana acceptor. Once that happens, the energy it took to achieve the transfer is stored in chemical form in the acceptor molecule and available for the final work of photosynthesis : the dark reactions, so names because they happen after light has been converted into energy. The dark reactions change carbon dioxide into carbohydrates and make sugars and proteins. /*---------------------------------------------------------------------*/ 96 Infinity plus 1 , surreal numbers The sqrt (infinity). 1/infinit. Just have to use the right numbers, open to surreal experiences /*---------------------------------------------------------------------*/ Personal Tech 3D TV Parvis Soltan - physicist. Hold a transparent cube, the TV screen of the future, see 3D images from any direction. Lab at US Navy C&C and Ocean surveillance center. 3' tall glass cylinder. Images come to life in 3D. Unlike holograms Soltan's volumetric display recreates a little 3D world in miniature. You can stand on tiptoe and look down at the scene, squat down and peer up at it, or walk around it to see the other side. Cables link soltan's cylinder to 2 foot square box of lasers, optics, and computers to produce 3D images. Glass cylinder encloses a short, squat plastic double helix 18inches high 24 inches in diameter. Helix spins 10 times/second fast enough to make it invisible. Mirrors at the top of the cylinder reflect pulses of light from a dozen red, green and blue laser beams down into the helix. The helix creates a visible point of light by rereflecting a beam. Constructs images by creating 120000 points. Voxels, volume picture elements 20times / second. Key breakthrough was to find a direct laser beams and make them voxels for a decent image. Hit upon tellurium dioxide crystals. Key characterisitc is that light passing through it tends to slow down as the density of the crystal increases. Soltan could bend a laser beam passing through the crystal simply by modifying the pressure on the crystal with ordinary sound waves. All that was left was to convert data representing 3D image into sound waves to control the laser beams. Machine turns the sound on turns it off repositions everything does it all over again in microseconds. A computer tracks the helix blade passing a zero point and how fast it is going. Sends the right voxel to the right place the right time. Airport controls , $85000 by dec. 1996 Hopes to use TV to convert magnetic resonance snapshots of patients tissue into 3D pictures. Switch to a cub shaped display solid glass or plastic cube is infused with rare earth phosphors which emit light when struck by 2 infrared laser beams. So can put a voxel anywhere in the cube. /*---------------------------------------------------------------------*/ Breakthroughs cyberwasps - how do social insects construct elaborate nests? French team showed just a small number of rules can construct a variety of nests. Bonabeau, Guy Theraulaz at National Center of Scientific research . If ou see a brick above you and to the left deposit a brick right where you are. if the insect doesn't find a pattern resembling the bricks around it, it wanders until it does. doesn't know that it is building a wall or a floor , merely obeys the rules triggered by the local shape of the hive. Health - post partum blues, hypothalamus secretes corticotropin- hormone CRH to fight stress. Raises blood sugar maintains normal blood pressure helps us perform well under stress.