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Blobrana


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Mass production of mirrors
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Title: Cold-shaping of thin glass foils as novel method for mirrors processing. From the basic concepts to mass production of mirrors
Authors: Rodolfo Canestrari, Giovanni Pareschi, Giancarlo Parodi, Francesco Martelli, Nadia Missaglia, Robert Banham

We present a method for the production of segmented optics. It is a novel processing developed at INAF-Osservatorio Astronomico di Brera (INAF-OAB) employing commercial of-the-shelf materials. It is based on the shaping of thin glass foils by means of forced bending, this occurring at room temperature (cold-shaping). The glass is then assembled into a sandwich structure for retaining the imposed shape. The principal mechanical features of the mirrors are the very low weight, rigidity and environmental robustness. The cost and production time also turns to be very competitive. In this paper we sum up the results achieved during the r&d performed in the past years. We have investigated the theoretical limits of the structural components by means of parametric finite elements analyses; we also discuss the effects caused by the most common structural loads. Finally, the process implementation, the more significant validation tests and the mass production at the industry is described.

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Blobrana


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RE: Transparent glass mirror
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Archaeological evidence suggests that glass was first made in the Middle East sometime around 3000 B.C. However, almost 5,000 years later, scientists are still perplexed about how glassy materials make the transition from a molten state to a solid. Richard Wool, professor of chemical engineering at UD, thinks he has the answer.
What distinguishes glasses from other materials is that even after hardening, they retain the molecular disorder of a liquid. In contrast, other liquids--for example, water--assume an ordered crystal pattern when they harden. Glass does not undergo such a neat phase transition; rather, the molecules simply slow down gradually until they are stuck in an odd state somewhere between a liquid and a solid.

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Blobrana


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Imagine a plane that has wings made out of glass. Thanks to a major breakthrough in understanding the nature of glass by scientists at the University of Bristol, this has just become a possibility.
Despite its solid appearance, glass is actually a jammed state of matter that moves very slowly. Like cars in a traffic jam, atoms in a glass cant reach their destination because the route is blocked by their neighbours, so it never quite becomes a proper solid.
For more than 50 years most scientists have tried to understand just what glass is. Work so far has concentrated on trying to understand the traffic jam, but now Dr Paddy Royall from the University of Bristol, with colleagues in Canberra and Tokyo, has shown that the problem really lies with the destination, not with the traffic jam.

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Blobrana


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Through the Looking Glass
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A whole new world came to life for Alice when she passed through the looking glass beetles with bad attitudes, Tweedledee and Tweedledum, smiling cats, talking tiger lilies and much more.
Mirrors have special powers in the real world too, especially in the hands of an astronomer. In fact, modern astronomy depends on mirrors. Almost every telescope uses a mirror, sometimes several mirrors, to gather and guide starlight toward some super-sensitive digital detector where a breathtaking image can be formed. Without mirrors, it would be almost impossible to study the universe.

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Blobrana


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Corning Museum of Glass
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Take one giant scoop of science and a heaping serving of art, add on a topping of hands-on arts and crafts and place it all in one fabulous package. Now you have the perfect recipe that makes the Corning Museum of Glass such a gem.
This spring, a new ingredient has been added to the mix: history.
On April 1, the museum, 75 miles west of Binghamton on Route 17, debuted the show "Curiosities in Glassmaking." While it may sound like an homage to the weird, the show is, in fact, a great way to learn all about world history, through the peculiar glass concoctions humans devised at various times.

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Blobrana


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High-performance mirror
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Engineers at the University of California, Berkeley, have created a new high-performance mirror that could dramatically improve the design and efficiency of the next generation of devices relying upon laser optics, including high-definition DVD players, computer circuits and laser printers.
The new mirror packs the same 99.9 percent reflective punch as current high-grade mirrors, called distributed Bragg reflectors (DBRs), but it does so in a package that is at least 20 times thinner, functional in a considerably wider spectrum of light frequencies, and easier to manufacture. All these characteristics present critical advantages for today's ever smaller integrated optical devices.

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Blobrana


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Glass
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In medieval European cathedrals, the glass sometimes looks odd. Some panes are thicker at the bottom than they are at the top. The seemingly solid glass appears to have melted. This is evidence, say tour guides, Internet rumours and even high school chemistry teachers, that glass is actually a liquid. And, because glass is hard, it must be a supercooled liquid.
Glass, however, is actually neither a liquid—supercooled or otherwise—nor a solid. It is an amorphous solid—a state somewhere between those two states of matter. And yet glass's liquidlike properties are not enough to explain the thicker-bottomed windows, because glass atoms move too slowly for changes to be visible.

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Blobrana


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Transparent glass mirror
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Although windows can naturally heat buildings in the cold seasons, during the summer they can easily overheat a building. To help with this problem, Japanese scientists at AIST recently developed a thin film which can make transparent glass turn into mirrors. The use of such a window in buildings or automobiles could reduce the energy consumed by air conditioners by more than 30%. The scientists, Kazuki Yoshimura and Shanhu Bao developed the thin film material. Previous research works have focused on the use of thin films made of magnesium-nickel alloy that behave as switchable mirrors: these, however, all have a yellow tinge in their transparent state.
The switching mechanism in Yoshimura and Bao’s window, is created by altering the gas content between the two glass panes. By introducing a small amount of hydrogen into the atmosphere between the panes, the glass acts as a transparent window. Alternatively, adding a small amount of oxygen with no hydrogen forms a reflecting mirror

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