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Today I am linking to videos mainly because they are cool and not because they have a strong tie to materials science. These short looping videos, which are oddly hypnotic (for me, anyway), are the work of Jean Rajchenbach, Didier Clamond, and Alphonse Leroux, whose paper on “Observation of star-shaped surface gravity waves,” is slated for a future issue of Physical Review Letters (preprint pdf).
The authors work at CNRS, in France, and their paper reports on their observation of new types of standing waves. Nonlinear effects in certain fluids, according to an email from the American Physical Society, “can give rise to remarkable phenomena such as ‘freak,’ ‘horse-shoe,’ and ’solitary’ waves (solitons), which sometimes are found to have important counterparts in other domains of physics, from optics to cold-atom physics. … The shapes of the waves are entirely determined by gravity, rather than surface tension, and can display a star-like or a polygonal shape, depending on the amplitude and frequency of the driving vibration. The resulting wave patterns, according to the authors’ model, stem from the resonant and nonlinear interactions between multiple waves traversing the liquid.”
As it it turns out, the emergence of the idea that solitons actually exist is a great example of early computer modeling and simulation. According to a separate APS story, the 1965 discovery and explanation for solitons was a direct result of the nascent computer technology available in federal lab. The story goes:
In 1955 Enrico Fermi, John Pasta, and Stanislaw Ulam (FPU) came across a puzzling result when using the MANIAC I computer at what was then called the Los Alamos Scientific Laboratory in New Mexico. They wrote a program to follow the motion of up to 64 masses connected by springs in a horizontal line. Each mass could move only in the direction of the line, stretching or compressing the two springs connected to it.
The team started the simulation by displacing each mass from its initial position in a pattern that formed one half of a sine wave, with the end masses having zero displacement and the middle masses having the greatest displacement. The masses would then oscillate, and if the springs were strictly linear—that is, if their force were proportional to the amount of stretch or compression—then a snapshot of the motion at any time in the future would show the masses still in a sine wave pattern. But Fermi and his colleagues added a small degree of nonlinearity to the springs’ force, expecting it to break up the sine wave and cause the oscillation energy to become, in time, equally distributed among all the masses.
That’s not what happened. Although the sine wave indeed evolved into a more complex oscillation, the motion of the masses never became completely disorderly, and in fact it periodically returned to the initial state.
A decade later, Norman Zabusky, then at Bell Labs in Whippany, N.J., collaborated with Martin Kruskal of Princeton University to re-examine the FPU work. They transformed the discrete masses-and-springs equation into one for a continuous system similar to water waves. The team then programmed a computer to calculate the wave motion over a fixed horizontal distance but in such a way that a disturbance passing out of one side of the range reappeared at the other side. Like FPU, Zabusky and Kruskal set the system in motion with an initial sine wave pattern. As the wave rolled along, its leading edge became steadily steeper and then developed smaller-wavelength ripples. These ripples eventually grew into individual waves that moved independently, with a velocity that depended on their height. Remarkably, when these new waves occasionally collided, they passed through each other, emerging almost wholly unscathed from their encounters. In addition, the waves would regularly align to reproduce the initial sine wave, momentarily, before separating again and repeating—not quite perfectly—the same cycle. This phenomenon was similar to the periodic return to the initial state that FPU had observed.
The discovery may have brought a sense of relief to those who had reported (documented sightings go back to the 1830s) seeing single waves in oceans and canals.
At $299 this is pretty pricey, however, I think the Nectar Mobile Power System, based on a mini solid oxide fuel cell that Lillipution Systems introduced this week at the CES show, could represent something of a breakthrough for consumer thinking about impact what larger-scale SOFCs could have once the technology matures.
What I mean is that, while I think a lot of people have heard about SOFCs (maybe from all the Bloom Energy publicity a while back), not many people have been able to see one up close and at a scale that they relate to.
The basic operations of the Nectar unit are pretty well demonstrated above. From what I understand, the attempt by Lilliputian to bring a mini SOFC to market goes back several years, and a Technology Review story in September reports that the company had first hoped it would occur in 2010. But, as is often the case, finding the right form factor and procuring several rounds of investments to allow for testing and ramping up production (while cutting costs) are well known bugaboos for developers. Lilliputian has been able to hang in there with big-league supporters, such as Intel and the venture cap group Kleiner Perkins Caufield & Byers. Another big investor is Rusnano, a Russian government-owned venture cap group.
The fuel cell itself starts life as a standard 8-inch silicon wafer, and is manufactured like a chip. This gives them fine control of the physical structures, if you can make sub-micron structures for a CPU, fuel cells are not a big deal to draw. Minute features and surface texturing that are impossible through conventional manufacturing processes are not just possible in a fab, they are almost trivial compared to a modern CPU. This is MEMS at best.
There are a few advances that Lilliputian has brought to the market, sealing tech and thermal management are two of the biggest. To generate 2.5W of electricity at a claimed 25% efficiency, you are going to need to dissipate 7.5W or so of heat. That is easy enough given the size of a pod, but the fuel cell needs temperatures of 600°C to operate, more is better. Getting rid of the heat isn’t the problem, keeping it in long enough is.
To this end, the cell itself operates under a vacuum to prevent thermal transfer. Keeping a vacuum in place over time is hard, but doing so with repeated thermal cycles to almost 1,000°C is very hard. Lilliputian came up with a novel glass sealing technology to do this, and since they have products coming to market, it appears to work.
The other way that you lose thermal energy is IR radiation, and for this, the cell is coated internally with reflective coatings, and hot spots are shielded with other structures to absorb IR wherever possible.
According to the Lilliputian website, the company was a startup launched by researchers who had been at MIT’s Microsystems Technology Laboratory who licensed technology from MIT and the Lawrence Livermore National Lab.
Is two weeks of cell-phone charging capability worth $300 to consumers. I am guessing there are a few, but not a lot. Lilliputian originally predicted a price point of around $100, which would probably snag quite a few more tech geeks. On the other hand, my guess is that this type of product first finds real interest in defense-oriented applications, and, there, money tends to be less important than performance. If the DOD isn’t interested, maybe the Russian army is.
“Massive open online courses” initiatives will not be confined to the West. India, via YouTube, has just launched a fairly impressive array of free, organized, undergraduate-level lectures that appear to be aimed, in large part, at providing broad public access to fundamental materials science and engineering topics, including a separate series of 50-60 minute lectures that focused on basic core glass and ceramics topics.
The reference to “India” isn’t a generic term; these online courses are part of an impressive national effort to broaden access to science and engineering education opportunities that stems from a specific policy and the creation of the country’s National Program on Technology Enhanced Learning (NPTEL). According to a 2007 agency document (pdf), NPTEL is ”a project funded by the Ministry of Human Resource Development [that] was first conceived in 1999 to pave the way for introducing multimedia and web technology to enhance learning of basic science and engineering concepts. …The broad aim of the project NPTEL is to facilitate the competitiveness of Indian industry in the global markets through improving the quality and reach of engineering education.”
One of the key NPTEL strategies is to leverage the knowledge and communications infrastructure of the Indian Institutes of Technology (IIT), the Technical Teacher Training Institutes (TTTI), and the Indian Institute of Science (IISc). During what it describes as “Phase 1,” NPTEL developed an initial set of videos and over 260 web-based courses available only through its website. With Phase 2, the program has expanded the availability of offerings to YouTube and is attempting to expand the course offerings to over 1,000 topics.
For example, the IIT and IISc in recent days have posted their “Processing of Non Metals” modules, which includes two lectures on “Engineering Materials and Processing,” plus specific series on glass (Module 2), ceramics (Module 3), and ceramic matrix composites processing (Module 6). Modules on plastics, polymers, and secondary processing of composite materials are also offered.
Here are some of the relevant videos (note: these can all be found on YouTube, directly, but NPTEL has aggregated links for the modules and lectures on a single page.
Mod-01 Lec-01 Engineering Materials and Processing Techniques: Introduction
Mod-01 Lec-02 Properties of Non-Metals
Mod-02 Lec-01 Glass Structure and Properties
Mod-02 Lec-02 Glass Processing—I
Mod-02 Lec-03 Glass Processing—II
Mod-03 Lec-01 Ceramics: I
Mod-03 Lec-02 Ceramics: II
Mod-03 Lec-03 Ceramic Powder Preparation
Mod-03 Lec-04 Ceramic Powder Preparation—I
Mod-03 Lec-05 Processing of Ceramic Parts—Pressing
Mod-03 Lec-06 Processing of Ceramic Parts—II
Mod-03 Lec-07 Ceramics: Secondary Processing
Mod-06 Lec-01 Ceramic Matrix Composites
Mod-06 Lec-02 Ceramic Matrix Composites: Fundamentals and Properties
Mod-06 Lec-03 Powder Processing: Ceramic Matrix Composites
Mod-06 Lec-04 Chemical Vapor Infiltration
Mod-06 Lec-05 Ceramic Matrix Composites: Processing—1
Mod-06 Lec-06 Ceramic Matrix Composites: Post Processing
While the production values of the videos aren’t groundbreaking, and are along the lines of a talking head and PowerPoint slides, this still seems to be a remarkable effort (although I would definitely delete the spinning NPTEL logo that appears throughout each lecture). Most of the lectures feature Inderdeep Singh, an assistant professor in mechanical and industrial engineering from IIT Roorkee.
In addition, within the past few days, NPTEL also has posted courses on chemical engineering design, special topics in atomic physics, spintronics, fuel cell technology, nuclear science and engineering, hypersonic aerodynamics, and advanced engineering thermodynamics.
Finally, NPTEL is starting to establish a schedule of “live” online courses during certain weeks of 2013. The courses will consist of two live online lectures (with quizzes) per week, plus graded assigned topics, midterm and final exams, discussion forums, and assistance from TAs. NPTEL is using Adobe’s Connect e-learning system to deliver these courses. While NPTEL says it only can provide a certificate for successful completion of the courses, it also is encouraging colleges and university to provide course credit wherever possible.
Speaking of India, I should point out that The American and Indian Ceramic Societies have been working to increase their ties and exchanges between the two organizations. As part of this cooperative effort, one of my colleagues, Megan Bricker, ACerS membership and marketing director, leaves tomorrow for an extended trip to India to confer with InCerS leaders and attend the Global Ceramics Leadership Roundtable Conference in Greater Noida. ACerS Immediate Past President George Wicks, plus Jay Singh and Tatsuki Ohji, leaders from the Society’s Engineering Ceramics Division, will join Bricker on this trip.
Bricker has promised to correspond with us during her trip, and I look forward to her reports.
Just as I finished my previous story on Gorilla Glass 3, Corning began a video dump onto YouTube. The one above is about the ion exchange chemical strengthening I wrote about earlier, and is sort of like an animated schematic. The title, “Why Glass Breaks,” is unfortunate, because that is a much longer and different topic.
Another one, below, elaborates on Corning’s other big product for CES, an optical cable that can unleash the real power of displays, computers, storage devices and other electronic gizmos that are starting to contain Thunderbolt ports (part of Intel’s Light Peak all-optical system). Current Thunderbolt connectors are really just copper cables and necessarily cannot exceed about 10 feet in length (3 meters). Most Thunderbolt systems will support transfer speeds of 10Gps, which is roughly equivalent to what the new USB 3.0 is supposed to deliver, but Thunderbolt/Light Peak can be jacked to 100Gps.
For several years, I’ve been hearing companies in the refractory services sector tout their ability to automate a lot of the steps of lining furnaces, but I have never witnessed it in person, nor seen exactly how its done, until I stumbled upon this video.
Various companies have their own proprietary systems, so there are many ways to accomplish the task, but I thought this video, produced by Gradmatic Equipment, at last gave me a good sense about how such systems could work.
Clearly, a lot of the equipment available is application-specific, and this video is only about installing refractory linings for coreless induction heating furnaces. The company does indicate that various furnace diameters can be accommodated and that it’s possible to use a similar system with ladles.
Regardless, I think the video does a nice job of contrasting manual methods to an automated system, and discusses health and safety issues, extension of lining life, materials requirements and labor costs.
I have no idea what a set of Gradmatic’s lining installation machines cost, and given the large variances in labor costs and concerns about worker silica exposure that exist around the world, there is no universal way to estimate payback times for such investments. But, the company says its customers report that lining life can improve by more than 67 percent, and, with the two-person system, the workforce can be reduced by more than 57 percent. An added measure is that Gradmatic says its customers report that the hours of labor required to replace a lining can be reduced by nearly 75 percent.
Gradmatic describes the emphasis on decreasing exposure to hazardous materials and more efficient use of materials as key parts of the “Green Foundry Concept.”