You are browsing the archives of 2008 December.

Kansas State University and Peregrine Semiconductors are demonstrating a battery-free technology that could improve embedded multi-sensor systems such as those that might be used to detect deterioration in busy bridge. “This type of radio technology may exist in your house, for instance if you have a temperature sensor outside that radios data to a display inside,” Kuhn said. “But those devices need to have their batteries changed. This radio doesn’t.” Peregrine Semiconductor says applications could include monitoring stress, temperature and pressure on bridges and other structures. K-State and Peregrine have already developed highly integrated, low power radio chips for NASA’s Jet Propulsion Laboratory using Peregrine’s UltraCMOS silicon-on-sapphire technology. The team has constructed a demonstration board using inexpensive solar cells to power the radio, but says they are also looking at piezoelectric, electrochemical and thermal energy approaches.

Again, we  present another beloved classroom demonstration in materials science. This one is a non-intuitive display of surface tension, residual stress, interior tension, potential energy and tempered glass.

To create a Prince Rupert drop, molten glass is dropped into cold water. The glass rapidly forms into teardrop shape with a extended, fine tail. The material in the exterior of the drop cools and hardens nearly immediate while the interior material cools slowly. As the interior material cools, it contracts and sets up powerful compressive stresses on the surface.

The residual stress within the drop gives rise to unique properties that every demonstrator loves: The drop can be hammered on the fat end without breaking, but disintegrates explosively if the tail end is even slightly damaged. This illustrates the release of the potential energy contained within the drop’s amorphous atomic structure.

The process of the “explosion” has been studied closely and shows that fractures move from the tail through the material at very high speed. Purdue University’s Srinivasan Chandrasekar used extremely high speed video to record how the “crack front” propagates in a disintegrating drop at up to 4,200 miles per hour.

The drops were supposedly discovered around the 1640s by Prince Rupert of the Rhine (1619–1682). The story is told that Rupert would use the drops as a practical joke in his court. He would give a drop to someone in his audience and then surreptitiously break the tail causing a small and surprising explosion.

We have actually combined two videos. The second part is slightly repititious but provides both a slo-mo view of the shattering process and a lovely image of namesake Rupert.

[flashvideo filename=wp-content/video/rupert_drop.flv image=wp-content/video/rupert_drop.jpg /]

Readers have expressed significant interest in our Dec. 5 post on the world’s third hardest material - BAM. Currently being tested at DOE’s Ames Laboratory as a nanocoating for machinery, BAM is thought to reduce machine friction and wear and, thus, make machinery operate more smoothly and energy efficiently. Because inquiring minds wanted to know more about BAM, I went back to the Ames researchers who discovered the new material and asked a few more questions. Here’s what I learned: 1.  There’s more than one type of BAM nanocoating. In fact, Alan Russell, an Ames researcher, co-discoverer of BAM and a professor of materials science and engineering at Iowa State University, says there’s “quite a range of compositions.” Russell notes the use of pure AIMgB₁₄ and AIMgB₁₄ + TiB₂ with varying ratios of AIMgB₁₄ to TiB₂. He says Ames is applying it by pulsed laser deposition but it can also be applied by magnetron sputtering, a technique better suited to commercial operations. 2. Long-term testing has been conducted on a range of rotating and sliding parts. These tests have compared bare steel, steel coated with diamond-like carbon and steel coated with BAM and BAM plus TiB₂. Russell says, while all coated parts “showed improvements in mechanical-running efficiency and start-up efficiency of one to eight percent,” BAM-coated parts performed best in two out of three tests. 3. While no definite answers are in yet, researchers do have some idea why BAM is so hard and slippery. Again, Russell is our information source:

“BAM’s high hardness is believed to result primarily from short, strong boron bonds and the small grain and phase size of the BAM and  TiB₂materials.”

He believes BAM’s slipperiness is the result of the “formation of hydrated boron oxide forming at the material’s surface from oxygen and water vapor in the air.” He notes, however, that “future tests of friction in high vacuum may refute or support [the hydrated boron-oxide] theory.” For those of you wondering about BAM’s potential application in combustion motor applications such as two-stroke engines, there does seem to be some promise:

“It’s almost as if it’s a self-lubricating surface. You don’t need to add oil or other lubricants. It’s inherently slippery,” he says, noting that “future tests of friction in high vacuum may refute or support [the hydrated boron-oxide] theory.”

4. I asked if he was concerned that BAM might one day prove harmful to workers, Russell responded:

“While boron has some mild toxic effects in extremely high doses, it is not generally deemed a hazardous material. Normal handling of bulk borides or coated parts is not considered a workplace hazard, nor is the dispersion of boron debris during use of the products.”

5. When I asked BAM’s other co-discoverer and Ames Lab researcher Bruce Cook when BAM nanocoatings might be taken to market, he reiterated that an Iowa-based start-up company, Newtech Ceramics, had licensed the BAM technology. He added, however:

“To my knowledge, there is no material in commercial use yet, although it appears this may change during 2009.”

To review a complete and updated version of the BAM story, check out the upcoming January issue of the Bulletin, ACerS monthly member magazine.

Duravit - a sanitaryware manufacturer with attitude - is on a mission. The company is determined to make toilets more visible and to change people’s attitudes about them so the humble “W.C.” gets more respect. This is the reason Duravit told famed French designer Philippe Stark to use a giant ceramic toilet as the centerpiece for its new design center in Hornberg, Germany. And Stark being Stark, did just that - creating a toilet several stories high - so large, in fact, it doubles as an observation tower where visitors gather to peer out on the surrounding town (see above). This is also the reason Duravit has done what no bathroom manufacturer has ever done before - opened a showroom for toilets and other sanitaryware on Madison Avenue, one of New York City’s toniest addresses in the very heart of its fashion district.

Known as “Duravit New York,” the new facility is designed to convey a sense of “water, air and sky metaphorically converged to produce a vast and weightless atmosphere where conventional intersections between wall, floor and ceiling fade away seamlessly,” a company press release says. Created by the German architectural firm of Schmutz & Partner, the showroom features carefully planned “D-cubes” - special areas built with their own roofs, floors, and ceilings, enabling them to reflect a wide range of changing surfaces and materials selected to “translate Duravit’s living bathroom environments into tangible bathroom vignettes,” as the firm’s press release describes. Special attention has also been given to the showroom’s paint and the arrangement of interior seating installations, media displays and product platforms. The result, Duravit believes, is a space that represents the successful marriage of two opposites - an expansive multi-sensorial showroom evoking wellness and tranquility, located in the heart of one of the world’s most hectic and fast-moving cities. The showroom and Duravit’s novel design center are only two of the attention-grabbing facilities Duravit has built throughout the world. The company also operates impressive flagship stores and showrooms calling attention to toilets and the other bathroom fixtures that Duravit manufactures in Meissen, Germany; Cairo, Egypt; Paris, France; and Shanghai, China.  

New plant in India: Now Duravit is out to conquer a new city. Only a month before its opening its New York showroom, the company laid the cornerstone for a new production facility it plans to build in Tarapur, India

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Scheduled for completion by the end of 2009, the new plant will employ 250 people and have a capacity of about 500,000 sanitaryware pieces per year, reports Franz Kook, chairman of Duravit’s management board. Kook says Duravit currently has production plants operating in Germany, France, Egypt, Turkey, China and Tunisia, in addition to distribution centers scattered throughout the world. Since Duravit has conducted business in Asia since 2003, Kook believes the firm has already established itself in the Indian luxury sector. The challenge for the Tarapur plant, he says, will be to open up a mid-priced market aimed at India’s rapidly-growing middle-class. Kook is also interested in developing “high-quality collaborations with local fitters and market partners.”  To accomplish this, the company will offer training seminars to show local craftsmen the fine points of bathroom installation and planning. One such seminar in 2007, attracted more than 500 attendees drawn from seven Indian cities, Kook says.

Opening new doors: “The bathroom is currently undergoing a major transformation as the notion of ‘living bathrooms’ gains momentum,” Kook states. “In contrast to the demands of everyday life, it offers modern users the desired space for relaxation and regeneration.” And, so, Duravit continues - one bathroom at a time around the world - boosting awareness and changing people’s attitudes about toilets and the rooms that house them.

Cellphones charged by voice sound waves. Drug delivery systems enabled by minute body movements. Military equipment powered by the motion of soldiers walking? Self-powered devices like these are now one step closer to reality thanks to a Texas A&M professor’s discovery that when certain piezoelectric materials are produced at the nanoscale - specifically at about 21 nanometers in thickness – they double their ability to convert mechanical energy into electrical energy. Conversely, when these piezoelectric materials are produced in sizes larger or smaller than about 20 to 23 nanometers, they lose substantial amounts of this energy-converting ability, says Tahir Cagin, the nanotechnology specialist who made the discovery, together with partners at the University of Houston. A pioneer in power harvesting - a field aimed at creating self-energized devices that don’t need power supplies replaced or recharged - Cagin has detailed his findings in a fall 2008 article in Physical Review B, published by the American Physical Society. As reported, the science of piezoelectrics is central to Cagin’s work.

Discovered by French scientists in the 1880s, piezoelectric materials - usually crystals or ceramics - generate voltage when a form of mechanical pressure is applied. Employed in World War I sonar devices, the technology is hardly new. Piezo materials are routinely used today in microphones, quartz watches, cigarette lighters and even in a handful of European nightclubs where dance floors have been built to transform energy from footsteps into lighting power and in a Hong Kong gym where exercisers’ energy is helping to power both lights and music. If the technology isn’t new, however, Cagin’s approach to it is. His focus is specifically on nano-sized piezoelectric materials. “When materials are brought down to the nanoscale dimension, their properties for some performance characteristics dramatically change,” says the past recipient of the Foresight Nanotech Institute’s prestigious Feynman Prize in Nanotechnology.

This finding and the knowledge that nanoscale materials are more “pliable and susceptible to change from their surrounding environment” have confirmed Cagin’s belief that miniscule changes in motion, presure and sound can be used to trigger nanoscale piezoelectric devices capable of powering everything from the delivery of drugs to the human body to the collection and conversion of sound vibrations into energy for cellphones, PDAs, laptops, mp3 players and an almost endless list of other low-powered electronic devices. “Even the disturbances in the form of sound waves such as pressure waves in gases, liquids and solids may be harvested for powering nano- and micro devices of the future if these materials are processed and manufactured appropriately for this purpose,” Cagin notes.