Saturday, April 29, 2006
Friday, April 28, 2006
Mechanics of Materials Research Impacts US Aluminum Industry, Energy, and Environment
The fundamental inability to reduce or eliminate these recovery losses is “lack of the integrated models that relate structural properties to manufacturing processes”. Currently, processing parameters are determined by trial and error and largely based on experience. This makes it difficult to optimize the process even on the macroscale level, and almost impossible from microstructure level. Research in the following areas are desirable:
- Develop integrated models to link microstructures to macroscopic properties of aluminum and rolling process parameters.
- Predict temperature, stress, strain, strain rate history, and damage revolution in hot rolling.
- Optimize processing parameters to reduce scrap in hot rolling, and validate the integrated models.
- Demonstrate the predictive ability of integrated model as a process optimization tool for hot rolling.
Tuesday, April 25, 2006
NSF Call for Proposal: Cyberinfrastructure Training, Education, Advancement, and Mentoring for Our 21st Century Workforce (CI-TEAM)
This NSF solicitation supports "Demonstration and Implementation Projects", e.g., research over multiple scales or across multiple disciplines.
Due date: 5 June 2006
Monday, April 24, 2006
The primary goal of the Predictive Science Academic Alliance Program (PSAAP) is to establish validated, large-scale, multidisciplinary, simulation-based "Predictive Science² as a major academic and applied research program. The Program Statement lays out the goals for a multiyear program as a follow-on to the present ASC Alliance program. This ³Predictive Science² is the application of verified and validated computational simulations to predict properties and dynamics of complex systems. This process is potentially applicable to a variety of applications, from nuclear weapons effects to efficient manufacturing, global economics, to a basic understanding of the universe. Each of these simulations requires the integration of a diverse set of disciplines; each discipline in its own right is an important component of many applications. Success requires both software and algorithmic frameworks for integrating models and code from multiple disciplines into a single application and significant disciplinary strength and depth to make that integration effective.
A pre-proposal meeting has been scheduled on May 16-17 at the Hyatt Regency at Dallas-Fort Worth Airport. For details. please refer to the website:
Sunday, April 23, 2006
Saturday, April 22, 2006
Merlot: a catalog of online learning materials for high education
But who has time for all this work? And how can we build an online community? Teng Li has begun to talk about these essential issues.
Perhaps a good starting point for us is to learn from successful Internet projects. I've written about Wikipedia and Slashdot. In this entry, I'd like to talk about Merlot.
Standing for Multimedia Educational Resource for Learning and Online Teaching, Merlot is a website that aggregates online learning materials for high education. Merlot was initiated in 1997 by the California State University Center for Distributed Learning. Today Merlot lists 499 items in Arts, 2407 in Business, 2052 in Education, 2257 in Humanities, 1130 in Mathematics and Statistics, 5699 in Science and Technology, and 979 in Social Sciences.
To learn how Merlot works, I clicked “DNA from the Beginning”, the fourth item listed in the category of Science and Technology. Listed on this Merlot page was an excellent website created by Cold Spring Harbor Laboratory. This item was added to Merlot in 2000 by a user named Jeff Bell, and reviewed in 2002 by the Merlot Biology Panel, which gave the item a rating of five stars. A total of seven users left comments, and all ranked the item with five stars. Four users created assignments to go along with the item. This item was collected by 104 users, whose personal collections I could also view.
I searched in Merlot using the keyword “mechanics”, and found 87 items, mostly on classical mechanics, quantum mechanics and statistical mechanics. I did find a number of items on applied mechanics, including ones on Strength of Materials, created by Mehrdad Negahban, of the University of Nebraska at Lincoln; and by Alan Zehnder, of Cornell University.
Anybody can view most of Merlot, but only members can submit new items, leave comments, etc. I signed on as a member, and submitted Applied Mechanics News as an item, which now has its own Merlot page. If you sign on as a member of Merlot, you can comment on this item, collect it, and submit new items.
You might want to explore the history of Merlot, and the structure of the Merlot community. To learn how to pronounce Merlot and hear a few sound bites, you might want to watch this short video.
We can learn many lessons from Merlot, but before we talk about these lessons, we ought to first spend more time to experiment with it. The number of excellent items is just astonishing, and Merlot has found ways to encourage users to participate.
Friday, April 21, 2006
Two reports on research directions in mechanics
Research in Fluid Dynamics: Meeting National Needs, prepared by a subcommittee of the US National Committee on Theoretical and Applied Mechanics.
Thursday, April 20, 2006
Saturday, April 15, 2006
AMN will link to blogs of individual mechanicians
As a part of the experiment, we’ll select each blog using the following criteria:
- The blog is actively maintained by one or a group of mechanicians.
- Entries of the blog are of interest to a large segment of the international community of Applied Mechanics.
- The blog will reciprocate by linking to Applies Mechanics News.
Friday, April 14, 2006
Ramblings on Solid Mechanics-Quantum Mechanics Link
In between writing proposals (—which apparently is what assistant professors mostly do now-a-days!), I read the entry by Professor Zhigang Suo on our identity as mechanicians. I found it very interesting and thought provoking. My senior mechanics colleagues inform me that this topic has, over the time, quite frequently been a subject of debate—as evident in Professor Budiansky’s Timoshenko speech in 1989. Zhigang’s particular blog post led me to think of the “mechanics” in another big mechanics area: “quantum mechanics”. While as a mechanics group we have been very active in seeking inroads into diverse fields (e.g. bio, electronic) it is interesting to note that with a few exceptions we have left untouched this fertile research area of quantum mechnics. There is a lot of “solid mechanics” to be done in “quantum mechanics”. A simple example is how mechanical strain impacts the band structure and hence opto-electronic properties of the exotic quantum dots. Ben Freund from Brown and Harley Johnson from UIUC were perhaps the first mechanicians to foray into this and, despite its extraordinary importance to nanotechnologies, applied and fundamental physics, only a few other mechanicians have since looked further into this. This example is symptomatic of a bigger issue. In recent years, physicists have become very preoccupied with mechanical effects and their coupling to quantum mechanical phenomena (and not just in quantum dots). Many essentially have become elasticians in a different guise; same subject but speaking a different language! –as evidence by numerous elastic effects articles that now appear in physics journals. Sometimes the solid mechanics is handled correctly but, in many instances, it is quite clear that the weight and might of decades of progress in solid mechanics (not readily on the radar screens of physicists) could be brought to bear on some of these problems.
Of course a major hurdle is that most mechanicians are not routinely trained in quantum mechanics. I contend though that if we can learn elasticity, quantum mechanics is yet easier! As an interesting aside, I note a beautiful and relatively lesser known paper by the famous mechanician, J.D. Eshelby (“The Interaction of Kinks and Elastic Waves”—Proc. Royal. Soc. Lond. A, Vol 266, n1325, 222, 1962). In this work he analyzes the movement of a dislocation kink. After a “conventional” mechanics approach---employed in typical Eshelby style to “extract maximal insights with minimal work”, he proceeds to analytically solve the same problem using quantum mechanics. That brief section in his paper, while perhaps obvious to many, was an epiphany moment for me that forever provided a link between the quantum and continuum world.
Although strongly biased (and constrained by my limited knowledge) I list here a few topics (among many others) that I think straddle quantum mechanics and elasticity. Hopefully other blog-members can add to the list or make one of their own fashioned after their own interests.
(1) Mechanical strain effects in quantum confinement in quantum dots, wires and wells—the easiest starting point is the book by Davies, (The physics of low dimensional nanostructures). Extensive work is available on strain effects on quantum dots in archival literature. In the mechanics community, Johnson and Freund have a few articles that are a good starting point. I have a review article on my webpage but that unfortunately only talks about strain calculations and not really the coupling to quantum effects. To my mind, given the all pervasive effects of strain in nanostructures in general, quantum dots are where solid mechanics meets head-on with quantum mechanics.
(3) A somewhat related issue to #1, is spin manipulations using strain. Traditionally, spintronics or possibly making advanced computers using electronic spin has been based on the use of magnetic fields. Two nice articles appeared in Nature that suggest how to manipulate spintronics using elastic strain: Flatte, “Relativity on a chip”, Nature, Vol 427, p 21, January 2004 and, Kato et. al., “Coherent Spin Manipulation without Magnetic Fields in Strained Semiconductors”, Nature, Vol 427, p 50, January 2004.
(3) Despite the passage of almost seventy years (when this topic first emerged), the precise definition of “quantum stress” still remains controversial. Here I am not referring to the so-called virial definition of stress used in empirical molecular dynamics but a quantum notion of stress. There is certainly a lot of scope for mechanicians to weigh in on this matter. The landmark paper on this appears to be, Nielsen, O.H. and Martin, R.M. ” Quantum-mechanical Theory of Stress and Force.” Phys. Rev. B 32(6), 3780-3791, 1985. The paper apart from clarifying several issues also gave rise to some controversies (some of which still remain unresolved as far as I can tell especially the issue of uniqueness of stress). Interested readers my wish to look at a review article I co-authored recently on this topic (available on my website). More recently, Rogers and Rappe have made a nice attempt to provide a geometric definition of the quantum notion of stress: Rogers, C.L. and Rappe, A. M., “Geometric formulation of quantum stress fields.” Phys. Rev. B 65(22), 224117 -224124, 2002
(4) What happens to Helium close to 0 K? At such small temperatures, liquid helium becomes a so-called “super-fluid” i.e. it can flow through narrow pores without resistance. A more exotic “supersolid” phase has been predicted theoretically with some controversial experimental evidence. Elasticity is expected to play a major role although I have not seen anything yet which puts this issue to rest—perhaps a mechanician can oblige? A good starting point and recent reference is: A. T. Dorsey, P. M. Goldbart, and J. Toner, ``Squeezing superfluid from a stone: Coupling superfluidity and elasticity in a supersolid,'' Phys. Rev. Lett. 96, 055301 (2006)
Thursday, April 13, 2006
What can mechanics community learn from the success of Google?
At $6 billion a year in revenue and $7.6 billion in cash, Google is a success. What’s more important to the rest of us, Google is running its business in a way that may change the world. Through its never-about-average products (i.e., Google search, Google Earth (and Mars too), Google Map, and more recently, Writely), Google is radically redefining the ways we obtain, organize, use, store, and share information.
So what’s Google’s secret to success? Quentin Hardy, of Forbes, interviewed Google CEO, Eric Schmidt and several VPs for answers. Here are excerpts from Hardy’s article:
- “The mission overall: to collect ‘all the world's information’ and make it accessible to everyone."
- “One true god rules at Google: data. The more you collect, the more you know and the more certain your decisions can be."
- “…this company loves to talk it out, jettison hierarchy, business silos and layers of management for a flatter, ‘networked’ structure where the guy with the best data wins.”
- “It shares all the information it can with as many employees as possible, encouraging debate but insisting on like-minded cooperation.”
- “Tackles most big projects in small, tightly focused teams.”
The information world Google is dealing with is, of course, many scales larger than the knowledge we mechanicians possess. The subject of mechanics, as part of the information world, however, shares many self-similarities with its matrix, such as
- “…accumulated over millennia has remarkable depth and richness. This large quantity of knowledge has made it hard for any individual to master (and to add to) the subject.” as described in Suo’s post.
- the knowledge in different disciplines of mechanics are largely scattered, instead of networked.
- an effective platform to exchange knowledge and stimulate interactions among mechanicians is desired.
- A startpage with Applied Mechanics News and its sister blogs keeps us updated with recent progress and latest events in our community;
- Applied Mechanics Discuss Group provides mechanicians a platform for information exchange and in-depth discussion;
- The Wikimechanics Project, when it is launched, will allow every mechanician to contribute in organizing the subject of mechanics.
Since these engineers at Google may change the world by exchanging ideas on weekly basis, we mechanicians may revitalize our community if everyone makes a contribution to the Internet-Based Mechanics (or iMech) project on a monthly basis. Not hard at all, right? It’s our community, let’s just do it.
My daughter is now at her curious-about-everything age. Why can she blow out bubbles from soap water but not from tap water? Why can Curious George ride his bicycle with just rear wheel on ground? You can imagine my difficulty in rephrasing surface tension and gyroscope effects in kid's language. I hope, if she raises similar questions in several years, I can just tell her, "Go ask iMech."
Tuesday, April 11, 2006
Internet as a platform for public outreach
The National Science Foundation has long been urging researchers to reach out to the public. The cause is noble and important, and most researchers love to share knowledge with others. However, developing successful modules takes time, which few are inclined to spend, especially if the modules are only used once or twice. As a result, many outreach efforts do not reach very far, if not outright perfunctory. This apparent problem seems to suggest an opportunity.
The use of a central repository such as the Internet to create, store and disseminate knowledge is truly a unique opportunity that has recently become available to millions of people of all ages. As a young academic interested in developing new ways to teach and also interest students in the sciences and engineering at an early stage, I am convinced that the Internet can play a significant role towards this effort.
The idea of creating webpages that discuss science to the non-scientists (or to students interested in identifying interesting fields outside of their core disciplines) can be a great way to interest school kids and undergrads to learn about applications of science and engineering in daily life. The Internet can thus be used as a popular means to introduce education early on which can often be very helpful to engage children and develop long term interest in the sciences.
In addition, the Internet can be used as a means to disseminate prepared information to a wide audience in multiple locations at different times. For example, a short presentation on device principles that are used to make a popular consumer electronics product such as iPod memory component can be used at schools or museums to discuss the contribution of an electrical engineer or a materials scientist to a young audience. This can in turn motivate students to potentially learn more about the science behind commonly used technologies that can in the future not only attract more students to pursue advanced studies in science or engineering but also in general to develop a scientific bent of mind. This can also help in general problem solving.
While the Internet already has a lot of information on many topics, it will be helpful to create well-designed portals of short courses that contain basic principles of a scientific discipline that can in turn be developed over a period of time by contributions from academics, students and teachers.
This entry includes suggestions from Zhigang Suo.
Sunday, April 09, 2006
Broadening the Reach of Mechanics
Who is touched by mechanics? Here are some obvious ones: mechanics academicians, students, regular users of mechanics in engineering practice, and workers in other fields that could benefit from mechanics insights.
Better educating students in engineering, and in mechanics in particular, is certainly one area that can benefit from the Internet. But, I want to offer thoughts on the last two groups, which get even less attention than students.
Once our students graduate and become engineering practitioners, are they served in any continuing way by the research output in our field? I suspect not, but perhaps this was not always the case. A friend, who is a retired VP from an aerospace company, has told me that he would follow the technical literature early in his career in industry, after completing his PhD. Later, he found less and less that spoke to his needs, and he eventually abandoned it. If that is the norm (and I suspect it is), are we happy? Maybe that is the norm in any mature field, with scholarly contributions far ahead of (but hopefully not irrelevant forever to) practice. But there is a gap, and only we can fill it.
Here is what I have believed is at least a part of the problem. Mechanics is a field that is broad and deep; not often do we push the edges in ways that are fundamental and broadly useful. But, we try. Still, why is that the only work product we value? This partially keeps us from serving practitioners. In my own experience, problems often arise in practice that do not demand a fundamental advance in mechanics or engineering science generally. They do require skill (sometimes approaching artistry) in integrating and adapting existing ideas and approaches. Could that knowledge and experience be recorded and retrievable (aside from issues of confidentiality)? Perhaps this becomes more feasible as we move to publishing modes that go beyond journals and include larger repositories. There is also a separate, non-negligible issue that the academy would need to devise some way of recognizing and rewarding insightful contributions that advance practice.
Why should we be concerned with researchers in other fields? I’ll pick on a personal example: my colleagues and I work on the problem of fracture during cryopreservation of biological tissues . (Others can point to their own examples of fields outside of mechanics that intersect their work.) Many of our papers are published in the cryobiology literature, and are intended to serve the community of cryobiologists. While the problem we address is viewed as highly significant by cryobiologists, we have a long way to go in helping them to understand our findings. More generally, how can we help potential scientific collaborators take advantage of the lessons of mechanics and be more effective collaborators with mechanicians? Of course, we should learn about their domain. But we must also make our ways of thinking more transparent to them.
In sum, I think we need both discussions: how our field can leverage the Internet and what goals should be served. One goal might be to make the insights of mechanics more widely appreciated. To do that, we must learn to better communicate what we do.
Saturday, April 08, 2006
Let us seize the greatest opportunity of our time
"The popular conviction that papers are doomed may cause owners and shareholders to prefer the cash-cow approach, accepting eventual oblivion while continuing to harvest billions of dollars in profits. Settling for a tolerable short-term future, newspapers could end up writing themselves out of the long-term one. Yet it’s also clear that this moment of supposed doom represents a sizable opportunity for newspapers, a chance to reinvigorate their product and, eventually, improve the economics of their business."
The newspaper industry is not the only one that faces crisis. So do many other established industries, as well as many academic disciplines. I'm not the first one to realize that, in Chinese, the word crisis means "danger and opportunity". When I first came to the United States for graduate study, twenty years ago, a popular topic was China's population. How would the country feed so many people? Well, we all know how by now. Instead of dwelling on the problem of feeding people, China has turned the people into consumers and manufacturers of the world. The problem of a large number has now turned into a great opportunity, and not for the Chinese alone.
Another popular topic twenty years ago was information explosion. How can we hand down knowledge to the next generation? How can a piece of information serve the public if few know it? Now Google and others have turned this problem into a hugely profitable business. What we see today in search and data mining, of course, is just the tip of an iceberg. Again, the problem of a large quantity is turning into a great opportunity, not just for a few companies, but for us all.
Let us mechanicians stop dwelling on our problems, of which there are many, but few are unique to the discipline of Mechanics. Let us think of ways to seize opportunities. Quite a few opportunities have been touched upon in earlier entries of Applied Mechanics News: Mechanics in Biology and Medicine, Integrated Structures, Simulation-Based Engineering Science, etc. You can add more to this list.
To me, the greatest opportunity presented to mechanicians of our time is the Internet. Ours is a subject with a long and complicated history. The knowledge accumulated over millennia has remarkable depth and richness. This large quantity of knowledge has made it hard for any individual to master (and to add to) the subject. However, nobody has ever questioned the value of Mechanics to a broad range of human activities today and to our posterity.
In a previous entry, I argued for initiating a Wikimechanics Project to organize, on the Internet, in a useful way, everything known about mechanics, from everyday experience to esoteric theories, and everything in between.
I have since discussed the matter with a number of colleagues, who have made suggestions. As a starting exercise, we can build an online community of mechanicians by creating and editing entries on Applied Mechanics in Wikipedia. As another exercise, we can take a subject like Strength of Materials, which is taught almost at every university, and involve mechanicians of several institutions and with different expertise to produce an iBook that incorporates texts, equations, pictures, movies and, yes, simulations like the web-based finite element simulations developed by Paul Steif and co-workers. Such an iBook will not be a clone of a paper book, but a platform for integrated and evolving learning tools.
The goal of these exercises will be to help us mechanicians develop an architecture of online collaboration, an architecture that
- motivates many mechanicians to contribute,
- produces quality products, and
- is scalable to more complex subjects.
True, the opportunity of the Internet is not specific to Mechanics, but the opportunity is almost exclusively ours to use the Internet to organize Mechanics, bountiful and beautiful. Computer Scientists will not do it for us, although they have a lot to offer. Nor will anybody else.
The Internet will enable us mechanicians to turn a large part of human knowledge into a huge opportunity: an old, complex, and useful discipline has its own advantage. We may call this opportunity Internet-Based Mechanics (IBM; or iMech, to be in tune with time).
If well done, Internet-Based Mechanics will make enormous impact on industries, education and public outreach, for many years to come, on a larger scale than the finite element method has done. It will also fundamentally alter how we conduct research in Mechanics. It forces us to be young and creative again.
Allow me to paraphrase a better known Bostonian. And so, my fellow mechanicians: ask not what the Internet can do for you - ask what you can do for the Internet. Let us seize the greatest opportunity of our time. The opportunity is for us all.
Acknowledgements. I've benefited from discussions with Paul Steif, John Hutchinson, Joost Vlassak, and Shriram Ramanathan.
Monday, April 03, 2006
Now everyone can post to the community
- Using an email address and a password to create a Google Account (if you don't already have one).
- Click "Sign in" at the upper-right corner of the Applied Mechanics Discussion Group. This leads you to a page where you can fill in the email address and the password of your Google Account.
- To post an item in the Discussion Group, click “Start a new topic”.
- To discuss any existing topic, click "Reply" at the bottom of each topic.
- You can get the RSS feed of the Discussion Group.
If you have further questions, email me. Give this Discussion Group a try!
Note added on 5 April 2006: The Applied Mechanics Discussion Group uses a free service called Google Group. In exchange for this service, Google inserts into the Discussion Group many ads, from which we receive no revenue. The ads, however, looks relevant to our community.