R. Salgado's Blog

Science, Engineering and Technology.

Friday, June 20, 2008

Academic Dishonesty According to Bloomberg

Scientific Fraud May Be More Widespread Than Thought, Poll Says
By Elizabeth Lopatto

June 18 (Bloomberg) -- About 1,000 potential incidents of fabrication, falsification or plagiarism in scientific research go unreported every year, according to a survey that suggests such misconduct is far more prevalent than suspected.

More...

Saturday, May 24, 2008

Jubilee Issue of Geotechnique Available

The foundation engineering paper in the 60th anniversary jubilee issue of Geotechnique can be downloaded from here.

Friday, March 28, 2008

U.S. News Ranking of Civil Engineering Programs

2008
1 University of California--Berkeley 4.7
2.University of Illinois--Urbana-Champaign 4.7
3 Stanford University 4.5
4 Massachusetts Institute of Technology 4.4
5 University of Texas--Austin 4.4
6 Georgia Institute of Technology 4.3
7 Purdue University 4.2
8 California Institute of Technology 4.1
9 University of Michigan--Ann Arbor 4.1
10 Cornell University 4.0 and Virginia Tech 4.0

2007
1. University of California–Berkeley 4.8
2. University of Illinois–Urbana-Champaign 4.6
3. Stanford University (CA) 4.5
4. Georgia Institute of Technology 4.4
5. University of Texas–Austin 4.4
6. Massachusetts Institute of Technology 4.3
7. Purdue University–West Lafayette (IN) 4.2
8. University of Michigan–Ann Arbor 4.2
9. California Institute of Technology 4.0
10. Cornell University (NY) 3.9 Northwestern University (McCormick) (IL) 3.9 Virginia Tech

Saturday, February 09, 2008

New NAE Members

New NAE Members:

Amadei, Bernard
Armstrong, Robert C.

Arvind

Assanis, Dennis N.

Austin, Wanda M.

Baughman, Ray Henry

Bhattacharya, Pallab K.

Blumberg, Paul N.

Brown, Gerald G.

Bruschi, Howard J.

Calabrese, Gary S.

Chang, Mau-Chung Frank

Cheng, Stephen Z.D.

Cundall, Peter A.

Dodds Jr., Robert H.

Dwork, Cynthia
Dzombak, David A.

Fiorato, Anthony E.

Fogarty, Thomas J.

Foley, James D.

Fu, Lee-Lueng
Grest, Gary Stephen

Grosz, Barbara J.

Haderle, Donald J.

Harrison, J. Michael

Hudson, John L.

Hunkapiller, Michael W.

Iglesia, Enrique
Kleinberg, Jon M.

Kurtz, Anthony David

Lin, Burn-Jeng

Lipo, Thomas Anthony

Livanos, Alexis C.

Lockett, Michael J.

Luenberger, David G.

Malkin, Stephen
Marr Jr., W. Allen

Martin, John C.

Miller, James A.

Mills, David L.

Nayar, Shree K.

Nikias, Chrysostomos L. 'Max'

O'Neill, Malcolm R.

Raghavan, Prabhakar
Rahmat-Samii, Yahya
Raibert, Marc
Rath, Bhakta B.

Richards-Kortum, Rebecca Rae

Robinson, Stephen M.

Rokhlin, Vladimir
Russell, Thomas P.

Sawyer, Robert F.

Sethian, James A.

Siegel, Paul H.

Singh, R. Paul

Sinha, Kumares C.

Sites, Richard L.

Spaepen, Frans
Suo, Zhigang
Tirrell, David A.

Walt, David R.

Weiner, Andrew Marc

Yeh, William W-G.

Yoon, Roe-Hoan
Yortsos, Yannis C.


New NAE Foreign Associates:


Akasaki, Isamu
Dowling, Ann P.

Healy, Thomas W.

Inoue, Akihisa
Leontiev, Alexander I.

Milner, Arthur John Robin Gorell

Ramm, Ekkehard
van Santen, Rutger Anthony

Watanabe, Tadashi

Sunday, October 28, 2007

Seeing the future (Forbes)

WWW Map

Tuesday, October 09, 2007

Calculus: Newton and Leibniz or Archimedes?

Saturday, October 06, 2007

What looks like a serious attempt at quantifying the quality of Ph.D. programs

This company has attempted to rank Ph.D. programs based on objective criteria (journal publications, grants, awards, etc.). It will be interesting to see how well that is done. I haven't had access to it yet.

Monday, September 24, 2007

From a 12th century Baghdad scholar to modern-day web-based software

This NYT article discusses the concept of an algorithm and its ubiquitous presence on modern-day websites.

Sunday, June 24, 2007

Metric_system.png (PNG Image, 1427x628 pixels) - Scaled (70%)

A little over two hundred years ago, the SI (International System) of units came into being. Although a bit abused (mainly in the US, where it is often referred to as the "metric" system), it has taken over the world. Well, almost all of it. The figure shows the countries that have not adopted it. Good geography practice too!

Metric_system.png (PNG Image, 1427x628 pixels) - Scaled (70%)

Saturday, June 02, 2007

BBC NEWS | Science/Nature | Nuclear reactor secrets revealed

This is rather interesting, in my view. It shows how, for these scientists, the concern for the consequences of their research clearly outweighed an interest in publishing. Extrapolating, this bigger-picture considerations should be more important to a scientist than publishing, securing research funds or any of the other things that academics tend to seek.

BBC NEWS | Science/Nature | Nuclear reactor secrets revealed

Tuesday, May 29, 2007

Outsourcing Versus Immigration - Forbes.com

Interesting reading for all "knowledge workers". Knowledge, being abstract, is easy to have flow through the Internet, which means these occupations are each time less protected from worldwide competition. The articles has an Atlas showing the countries that are participating in this new way of trading in services.

Outsourcing Versus Immigration - Forbes.com

Sunday, May 20, 2007

Web 2.0

After the pop of the internet bubble, survivors and a number of new companies started pursuing a set of concepts that has become known as Web 2.0. A bit controversial, the term in general applies to the increasing use of the web as a platform for activities that one in the past
would do in a PC or workstation, using DOS or Windows or UNIX and to the increased interactivity and participation of users in shaping services. In a series of brief posts, I will try to very simply outline a number of examples of such activities.

One trend that has been in place for a few years is the mashup or repackaging of existing services. An entertaining example is Gahooyoogle. This service displays both the Yahoo and Google search results side by side. There are plenty more, from the trivial to the more elaborate.

The Surprising Truth Behind the Construction of the Great Pyramids | LiveScience

Thursday, May 17, 2007

Will Universal Search Mean Universal Domination?

Sunday, May 06, 2007

The difficulty of making predictions

I have this habit of trying to spot trends. This is useful because trends, despite the absence of any proof, do develop because of something similar to Newton's laws of mechanics. Unless an "external force" comes into the picture, trends tend to stay in place because more and more people jump on the bandwagon, until the "supply" of people finally ends. Spotting trends is helpful in not making wrong predictions. But, as someone said, making predictions is hard, "especially about the future", as the following illustrate. This list expands on the one linked to here.


"Man will never reach the moon regardless of all future scientific advances."
-Dr. Lee DeForest, "Father of Radio & Grandfather of Television."

"The Atomic bomb will never go off. I speak as an expert in explosives."
-Admiral William Leahy, US Atomic Bomb Project

"There is no likelihood man can ever tap the power of the atom."
-Robert Millikan, Nobel Prize in Physics, 1923

"Computers in the future may weigh no more than 1.5 tons."
-Popular Mechanics, forecasting the relentless march of science, 1949

"I think there is a world market for maybe five computers ."
-Thomas Watson, chairman of IBM, 1943

"I have traveled the length and breadth of this country and talked with the best people, and I can assure you that data processing is a fad that won't last out the year."
-The editor in charge of business books for Prentice Hall, 1957

"But what is it good for?"
-Engineer at the Advanced ComputingSystems Division of IBM, 1968, commenting on the microchip.

"640K ought to be enough for anybody."
-Bill Gates, 1981

"This 'telephone' has too many shortcomings to be seriously considered as a means of communication. The device is inherently of no value to us,"
-Western Union internal memo, 1876

"The wireless music box has no imaginable commercial value. Who would pay for a message sent to nobody in particular?"
-David Sarnoff's associates in response to his urgings for investment in the radio in the 1920s.

"The concept is interesting and well-formed, but in order to earn better than a 'C,' the idea must be feasible,"
-A Yale University management professor in response to Fred Smith's paper proposing reliable overnight delivery service. (Smith went on to found Federal Express Corp.)

"I'm just glad it'll be Clark Gable who's falling on his face and not Gary Cooper,"
-Gary Cooper on his decision not to take the leading role in "Gone With The Wind."

"A cookie store is a bad idea. Besides, the market research reports say America likes crispy cookies, not soft and chewy cookies like you make,"
-Response to Debbi Fields' idea of starting Mrs. Fields' Cookies.

"We don't like their sound, and guitar music is on the way out,"
-Decca Recording Co. rejecting the Beatles, 1962.

"Heavier-than-air flying machines are impossible,"
-Lord Kelvin, president, Royal Society, 1895.

"If I had thought about it, I wouldn't have done the experiment. The literature was full of examples that said you can't do this,"
-Spencer Silver on the work that led to the unique adhesives for 3-M "Post-It" Notepads.

"Drill for oil? You mean drill into the ground to try and find oil? You're crazy,"
-Drillers who Edwin L. Drake tried to enlist to his project to drill for oil in 1859.

"Stocks have reached what looks like a permanently high plateau."
-Irving Fisher, Professor of Economics, Yale University, 1929.

"Airplanes are interesting toys but of no military value,"
-Marechal Ferdinand Foch, Professor of Strategy, Ecole Superieure de Guerre, France.

"Everything that can be invented has been invented,"
-Charles H. Duell, Commissioner, US Office of Patents, 1899.

"The super computer is technologically impossible. It would take all of the water that flows over Niagara Falls to cool the heat generated by the number of vacuum tubes required."
-Professor of Electrical Engineering, New York University

"I don't know what use any one could find for a machine that would make copies of documents. It certainly couldn't be a feasible business by itself."
-the head of IBM, refusing to back the idea, forcing the inventor to found Xerox.

"Louis Pasteur's theory of germs is ridiculous fiction."
-Pierre Pachet, Professor of Physiology at Toulouse, 1872

"The abdomen, the chest, and the brain will forever be shut from the intrusion of the wise and humane surgeon,"
-Sir John Eric Ericksen, British surgeon, appointed Surgeon-Extraordinary to Queen Victoria 1873.

"There is no reason anyone would want a computer in their home."
-Ken Olson, president, chairman and founder of Digital Equipment Corp., 1977



Source: bigpicture.typepad.com

Wednesday, May 02, 2007

DRM lobby scrambles to block HD DVD crack - 02 May 2007 - Computing.co.uk

Monday, April 30, 2007

Big Money in Little Screens - New York Times

Open Culture: 10 Unexpected Uses of the iPod

Thursday, April 26, 2007

Latin phrases used in English

Tuesday, April 24, 2007

Digg.com reveals news stories fade after 1 hour - tech - 24 April 2007 - New Scientist Tech

Monday, April 23, 2007

Some very funny and totally wrong predictions of the past | Thought Mechanics

Monday, April 09, 2007

Big Bang at the atomic lab after scientists get their maths wrong-News-UK-TimesOnline

Sunday, April 08, 2007

Speedup Windows XP in Minutes! | Mobile Pedia

Robert Heinlein at One Hundred @ Blogcritics.org

Saturday, April 07, 2007

Building The Infinite Internet - Forbes.com

How Number Nifty Are You? - Forbes.com

Impressive origami

The Best of Origami

The first time I paid any attention to origami was when I was presented with a gift by Prof. Madhav on one of his visits to Purdue. The gift was a chicken, standing elegantly on its two legs (it has since lost its balance, despite my attempts to set it right by bending it here and there). So I return the gift...

Sunday, April 01, 2007

Reuters AlertNet - FACTBOX-Reports by the U.N. climate panel

University of Illinois Joins with RIAA

George Orwell, Big Brother is watching your house | News | This is London

Monday, March 26, 2007

collision detection: How scientific language erodes public trust in science

What's in word? If the word is theory, there is a biad that comes with it that many scientists would wish were not there: How scientific language erodes public trust in science

Tuesday, February 06, 2007

Neatorama » Blog Archive » 11 Most Important Philosophical Quotations.

Saturday, January 27, 2007

US answer to global warming: smoke and giant space mirrors | Climate change | Guardian Unlimited Environment

Tuesday, January 16, 2007

New Scientist: In the beginning was the bit

dilbert.linux.gif (GIF Image, 600x384 pixels)

Saturday, January 13, 2007

Some Interesting and Fun Links

The economic implications of the Web and the Internet are often discussed. What may be missed in the calculations is how much time people "waste" learning about oddities that they would never have learned about before (and that would not have made any difference to know anyway). This particular one is interesting because every mechanician has to draw a Mohr circle once in a while. When I draw them, I usually warn students that my circles are the worst in the world (a slight exaggeration). This gentleman does not need to do that, and everyone seems to have a lot of fun with his skill. I am sure his teaching evaluations go up by a point or two because of his circle-drawing ability!

Scientists have something to say about doomsday.

The importance of perspective: is there something wrong with this structure?

For aspirng experimentalists and EE students: how to solder.

Struggling with passwords is a real problem. You don't want to write them down for obvious reasons. Then you forget them and have to ask them e-mailed back to you, and then waste considerable time generating a new one because the one that was send to you is absolutely beyond anyone's capacity to remember (of course, as I say this, there will be someone that will show up on youtube with limitless memory...). I am no cryptography expert, but this does seem like the ultimate solution for password troubles and time waste.

Every engineer knows that China has become the manufacturing center of the world, and India the IT/Services center of the world. There have been some other smaller players participating. The news is that China is now becoming too expensive to manufacture the cheap things ("junk") that people in the U.S., in particular, have become used to consuming (note: consume is the right word; we are literally consuming away our planet, but that is another subject).

Apple would like us "Inside the Image" to show us "How scientists see the world".

Missing university lectures? Wanting to watch PBS documentaries without ever leaving your computer? No problem, this site has it all for you. Speaking of never leaving your computer, http://www.sellsbrothers.com/ brings us the figure below. So true...



Sunday, January 07, 2007

ABC News: The Science of Evil

Saturday, December 30, 2006

Ancient ice shelf snaps and breaks free from Canadian Arctic - Americas - International Herald Tribune

Some links to start the year with. Happy 2007!

Another year is behind us. I decided to end the year looking at some of what the Web has of interest that falls on the light side of things. There is bad news out there, including many that are closely related to science and technology (notably global warming and the bird flu), but this is not the time for that.

After the Nasdaq bubble burst of 2000, there was considerable doubt about which companies would survive and what would be of internet companies. A new generation of companies is out with very good stuff, and many new websites and new ideas are out there now. Time magazine has a list of what they consider the 50 coolest websites. Many of these are built on the basis that people want to participate and share and that others are interested in what the first group have to contribute. This led to the controversial, to settle for an uncontroversial word, selection of you as Time Person of the Year.

When I think of the difficulties of being a scientist in the true sense of the word, I always think of Weggener, and the difficulties he met going against the prevailing paradigm in geology in his time when he proposal his continental drift ideas, which eventually led to plate tectonics theory. Tnings have gotten harded in our days. Bureaucratic pressures can make it really difficult for someone intent on doing independent, objective scientific work. A few months ago I saw a 60 minutes' interview with a scientist whose reports were being heavily edited by his superiors, with deletion of anything that sounded conclusive regarding the existence of global warming. Now this about the Grand Canyon puts some geologists in a difficult position.

Back to global warming, I finally saw Al Gore's movie, An Inconvenient Truth, a few weeks back. It was really well done, and I believe it can be credited with the improvement of the tone of coverage of the global warming issue in the media. Now perhaps he no longer needs to claim credit for having invented the internet, for this movie was a very positive contribution.

Looking for something to do with you head these last days of the year? Try this calculation (in your head!): Take 1000 and add 40 to it. Now add another 1000. Now add 30. Add another 1000. Now add 20. Now add another 1000. Now add 10. What is the total? 5000? For an answer that is surprising to most who try this and other mind-tripping questions, go here. This comes out of digg.com, one of the 50 "coolest" sites I mentioned earlier, in which news are listed in the order in which they are voted. The website seems to be visited by computer-oriented people in significant numbers, which gives it a nice tech (sometimes nerdy) bias.

Interested in succeeding in 2007? Lots of advice from well known people could help. However, I always consider such things in the context of the role chance plays in life (the best book discussing this in a scientific literate manner is Taleb's Fooled by Randomness).

If you are into best- or worst-of-the-year type lists, this will have what you want.

Finally, a small Chirstmas gift that will help type those foreign characters in the titles of papers written in foreign languages in the list of references of your next paper.

Happy 2007!

Monday, December 25, 2006

The Year Ahead: Tech Predictions For 2007 - Tech News - Playfuls.com - Science & Technology

The Year Ahead: Tech Predictions For 2007 - Tech News - Playfuls.com - Science & Technology: "What's ahead in the world of technology in 2007? No one can say for sure, but that doesn't make the tradition of making predictions any less enjoyable. More than many other areas, technology is all about transition. And the year ahead promises transitions in tech that are nothing short of dramatic. "

Sunday, December 17, 2006

Healthbolt » What Happens To Your Body If You Drink A Coke Right Now?

Although I never read it, there was a book many years ago, called Sugar Blues, which described in detail the effects of the consumption of sugar to one's body. A nice timeline of these effects, for a Coke drink, can be found here.

Tuesday, December 12, 2006

Noise in Computing: A Primer | silentpcreview.com

In the past, in looking for performance, I found noise in a newly purchased computer. This article discusses computer noise in the context of background noise. In summary, a gamers' PC or a high-performance computational system, unless purchased from special shops, will produce noise of at least 40dB. A good general-purpose system can be purchased that will produce less than 30dB of noise from regular commercial outfits (Dell's Optiplex series, for example, is fairly silent).


SPL (dB) TYPICAL ENVIRONMENT AVERAGE DESCRIPTION

140 30 meters from military aircraft at take off Threshold of pain
120 Boiler shop (maximum levels)
Ships engine room (full speed) Almost intolerable
100 Automatic lathe shop
Platform of underground station (maximum levels)
Printing press room Extremely noisy
80 Curbside of busy street
Office with tabulating machines Very noisy
60 Restaurant, Department Store; Noisiest Gamer PC Noisy
50 Conversational speech at 1 meter; Noisy workstation Clearly audible
35 - 45 Quiet office or library; Typical PC Subdued
25 - 30 Bedroom at night, Quiet PC Quiet
20 - 25 Quiet whisper; Very quiet PC
Background in TV and recording studios Very quiet
15 - 20 Super quiet / fanless PC Barely audible
<15 Sounds of internal organs Normally inaudible
0 'Normal' threshold of hearing Not audible

Sunday, December 03, 2006

Ten Tips for Smarter Google Searches > Tip #1: Use the Correct Methodology

Ten Tips for Smarter Google Searches > Tip #1: Use the Correct Methodology: "Most people use Google in a very inefficient and often ineffective manner. If all you do is enter a few keywords and click the search button, you're one of those users who don't get as much out of Google as you could. In this article, Google expert Michael Miller shows you how to search smarter — and more effectively."

Blade Runner and Philip K. Dick

In 1982, almost 25 years ago, I came from Brazil to visit my sister, who was an exchange student at the time. During a couple days spent in New York City, we somehow ended up in a movie theater, of all places, to watch Blade Runner. That was the first of several times I watched the movie, which I consider a masterpiece, on a par with 2001 - A Space Odissey, in the science fiction genre.

Blade Runner is based on a novel by Philip K. Dick, a Berkeley author with what I consider rare creativity. His novels are rich in ideas and imagery (according to reports, helped by Dick's use of drugs) but are quick reads. There isn't a lot of time put into character development, for example, but the stories do get you to think. "Blade Runner", the movie (yahoo; amazon), deals with tremendouly appealing issues to me: what constitutes our identity, how we should treat those different from us, the dehumanization of people who authority wants to destroy, the possibility of understanding the meaning of the world and of life to a degree that we transcend ego, and the impact that technology and its close association with profit will have on our world as population growth magnifies the market for technology and thus its role? The movie is, in addition, visually stunning, and way ahead of its time. The acid rain, that never stops falling, hints at problems we have today, with the ever-growing concentration of CO2 in the atmosphere responsible for global warming and for increasing acidity of our oceans. The soundtrack, by Greek composer Vangelis, is the best of any movie I have seen.

Interestingly, reception to the movie was initially cool, to say the least. It took some time for people to recognize the quality of this movie and the strength of its story. Eventually, the movie rekindled interest in Dick, with many more of his stories made into movies, A Scanner Darkly being the most recent one.

What got me going with this? I ran into this documentary on google video, which is very well done:

http://video.google.com/videoplay?docid=3807826142091223684

Sunday, November 26, 2006

What the future holds, or so they think...

Sunday, November 19, 2006

Online lectures - various universities

A View from Above

Some very beautiful photos of a variety of things, from volcanoes to residential neighborhoods, from a very consistent angle...

WebПарк.ру: Мир сверху (55 фото)

Saturday, November 04, 2006

Bloomberg.com: Worldwide

Bloomberg.com: Worldwide: "World Fisheries Risk Collapse by 2048, Scientists Say (Update2)

By Alex Morales

Nov. 3 (Bloomberg) -- The world's ocean fishing grounds may be almost exhausted by 2048 if catches and pollution aren't limited, according to scientists who conducted a four-year study.

The rate at which stocks in the fishing areas have collapsed is accelerating, the scientists led by Boris Worm of Canada's Dalhousie University said today in the journal Science. A seafood species is said to have collapsed when the catch falls below 10 percent of the maximum annual haul. By 2003, 29 percent of seafood species were in that category, the scientists said."

Saturday, October 28, 2006

Image:Snowflake 300um LTSEM, 13368.jpg - Wikipedia, the free encyclopedia

Sunday, October 22, 2006

RealEstateJournal | Ten Innovations That Will Reduce The Amount of Energy We Use

I'd like to comment on this but need to find the time...

RealEstateJournal | Ten Innovations That Will Reduce The Amount of Energy We Use

Thursday, October 12, 2006

A Nice Tool for Dealing with File Type Inflation

Wednesday, October 11, 2006

Seed: Science 2006

Sunday, October 01, 2006

A New website on higher-education jobs

This relatively recent website seems well put together and may be useful to those seeking academic jobs:

Higher Education Jobs

Friday, September 22, 2006

Rodrigo Salgado - Science, Engineering and Technology Blog

I am teaching theoretical geomechanics this semester. I've compiled this list for my students, which may be of interest to those visiting who have an interest in mechanics:

Rodrigo Salgado - Science, Engineering and Technology Blog

Through our own eyes

From the NYT, 20060922 , a quote from Chomsky that I wish to save: “We should look at ourselves through our own eyes and not other people’s eyes". This he apparently said to the NYT reporter who called his home to check whether he was alive. The Venezuelan president Hugo Chavez had indicated in a news conference that he regretted not having had met Chomsky before his death, all of this related to Chavez's recommendation of Chomsky's book, which was propelled by this recommendation to the absolute No. 1 Amazon's bestseller. At any rate, what focused my attention on this quote is the fact that much of the workings of academia is based on looking at yourself through other peoples' eyes and yet here is an academic saying otherwise. Much of academia is based on staying with the program, with the prevailing paradigms, for this brings the fastest benefits, whether it be accepted papers or funded proposals, but most of the great progress in science came from breaking with the prevailing paradigms. I think that this is worth pondering.

Sunday, July 16, 2006

Best Scientists

It was unavoidable that, given what is happening in the world, a quote by Noam Chomsky would find its way to my computer screen: "The best scientists aren't the ones who know the most data; they're the ones who know what they're looking for." I think this is mostly right. It speaks to focus and to reluctance on going off on tangents when you have a clear research goal. There are of course times when one should allow oneself the freedom to scan, and read and take those tangents to see where they might lead, but consistently doing that will probably lead to very few results.

Friday, July 14, 2006

This blog appears as 18th of 100 top engineering blogs:

18: R. Salgado's Blog BlogShares profile
Last Indexed: 11:20 13 Jul 2006

Saturday, July 08, 2006

Where in the world?

Where in the world are people searching for the terms "foundation engineering on Google? See here.

Saturday, June 03, 2006

Top Ten Engineering Flops

This list of the top ten engineering mistakes ever made illustrates the need for fully visualizing everything that could wrong with a design so that these outcomes may be prevented.

Sunday, May 28, 2006

What amazing things a knowledge of mechanics, skill and experience let you do!

This is one of the coolest videos I have seen: can you poor someone a drink while upside down?

Saturday, May 27, 2006

Transitioning from a linear to a non-linear world: what doors does that open?

I practice in a field that deals with strongly nonlinear materials (granular media). These materials have in esence no linear elastic range to speak of. They can also both strain-harden and strain-soften, depening on conditions. So constitutive models must be very complex in order to capture all the nuances of mechanical response. Numerical challenges also exist. For example, shear strains tend to localize intensely for strain-softening materials. The numerical models needs to capture that. Other numerical challenges include dealing with action near the yield surface. Today, although still expensive, analyses of boundary-value problems using such models and techniques are possible. This will open doors, answer questions in rigorous and realist ways. But will practitioners wish to walk through these doors?

The Geo-Engineering profession has long dealt with the inability of analysis (which has typically been based on linear elasticity and/or perfect plasticity) to provide realistic answers by discounting analysis as simply a tool to provide general guidance. Empiricism has, as a result, dominated. This has left us with a traditional approach to graduate education that has left many unprepared to reap the benefits of the hard work that has been put into arriving to where we are by a generation of mechanicians and analysts. In 5 years or so, the analyses I spoke of will likely be much more economical to perform. The question for me is: will our engineers embrace these analyses and the benefits that can result from them or will they shun them and stick with traditional practices?

Saturday, April 29, 2006

The Gutenberg Project

http://www.gutenberg.org/browse/scores/top

Sunday, April 02, 2006

U.S. News and World Report Rankings: Engineering Schools

When I was a graduate student at UC Berkeley, the U.S. News Rankings were not yet established as an important reference for students, faculty and administrators. They are now. The new engineering rankings are:

1. Massachusetts Institute of Technology
2. Stanford University
3. University of California - Berkeley
4. Georgia Institute of Technology
5. University of Illinois - Urbana-Champaign
6. Purdue University - West Lafayette
University of Michigan - Ann Arbor
8. Carnegie Mellon University
9. University of Southern California (Viterbi)
10. California Institute of Technology


As pointed out by Mark H. Karwan, the engineering dean at Buffalo, some of the criteria used in the U.S. News rankings reward schools that have higher numbers of faculty and students. So a Dean, to have her school climb in the rankings, may simply negotiate for a larger number of faculty positions, for example, so that the ascension in the rankings may not necessarily reflect a qualitative improvement in the College. In contrast, in the specialty rankings, perception is everything, as programs are ranked based on an assessment by peer departments at other universities. The question then is: what has changed in a given school to justify the rise or fall in the rankings. Just a few of the questions to ponder when using rankings as a factor in decision making.

Sunday, March 26, 2006

Britain, UK news from The Times and The Sunday Times - Times Online

Britain, UK news from The Times and The Sunday Times - Times Online: "DOZENS of the world’s cities, including London and New York, could be flooded by the end of the century, according to research which suggests that global warming will increase sea levels more rapidly than was previously thought.

The first study to combine computer models of rising temperatures with records of the ancient climate has indicated that sea levels could rise by up to 20ft (6m) by 2100, placing millions of people at risk."

Monday, March 20, 2006

Applied Mechanics Research and Researchers

Applied Mechanics Research and Researchers: "Recently I attended the annual American Physical Society conference held in Baltimore (during the week of March 13th). One of the non-technical sessions included presentations by the APS journal editors--Physical Review A/B/C/D/E and Letters---and a panel discussion related to these journals. Since many of our mechanics and materials colleagues nowadays are interested in publishing in these journals, I thought I should post a link to some of the slides (from the editors presentation) that I found interesting. Many of the slides presented at APS are in the linked pdf file that also includes additional (humorous slides!) regarding reviewer issues.

Essentially, the graphs in the presentation depict a telling trend regarding globalization of research. Until 1995, US submissions to PRL dominated with western Europe and rest of the world following (in that order). In 1995, western Europe overtook US. Since last year, the rest of the world has overtaken BOTH western Europe and US. By the 'rest of the world', the editor is essentially referring largely to China, and partly to India and eastern Europe."

Applied Mechanics Research and Researchers: Continuum Mechanics books, Abramowitz and Stegun, downloadable

Applied Mechanics Research and Researchers: Continuum Mechanics books, Abramowitz and Stegun, downloadable: "Books on continuum mechanics freely available on the web. Of particular note,

'Introduction to Continuum Mechanics for Engineers' by Ray M. Bowen
http://www1.mengr.tamu.edu/rbowen

'Continuum Mechanics' by George Backus
'Continuum Mechanics' by Brian Kennett
both at http://samizdat.mines.edu
The samizdat site has links to many other texts, particularly in geophysical applications.

Not continuum mechanics but useful if you have ever used the hard copy:
'Abramowitz and Stegun: Handbook of Mathematical Functions'
The copyright is in the public domain. The book can be downloaded from http://www.math.sfu.ca/~cbm/aands
Keep the html version on your PC and you can get that Bessel function relation in no time."

Tuesday, March 14, 2006

The Laws of Thermodynamics

The first law of thermodynamics states that the energy of a system increases by an amount equal to the heat transferred into it less any work done by the system on its surroundings.

The second law of thermodynamics states that the entropy of a (theromdynamicall isolated) system tends to increase over time, even in the absence of any heat change. Systems may be classified as:

  1. Isolated Systems - matter and energy may not cross the boundary.
  2. Adiabatic Systems - heat and matter may not cross the boundary.
  3. Closed Systems - matter may not cross the boundary.
  4. Open Systems - heat, work, and matter may cross the boundary.

Dimensionally, entropy has units of heat per absolute temperature. Should heat increase by some small increment, the entropy of the system increases by an amount equal to heat increment divided by the absolute temperature. A more general definition is required for irreversible processes.

Entropy - A Powerful Concept

Entropy is a powerful concept. In thermodynamics, it represents the amount of energy in a system that cannot do useful work. For example, let us say a system initially was not in equilibrium and, as a result, one part of the system may have moved against the other (doing work) or the temperatures of the two parts were different intially but then equalized. After these processes are over, the system will be in equilibrium, will still have some energy, but this energy will not be usable to perform any additional functions. The system's entropy is a measure of that unusable energy.

An analogous, and, some suggest, more general concept was proposed by Claude Shannon in the paper from which information theory sprang. Entropy in the context of information theory is related to how much of the content of any signal (which could include a typed page of text, which is nothing mroe than a string of characters) is random and therefore has no information content. The concept has also found applications in fields apparently so disconnected as genetics and trading/investing. More on that some other time.

Monday, March 13, 2006

THE SOMETIMES OVERWHELMING TERMINOLOGY OF CONTINUUM MECHANICS


I am teaching a plasticity theory course at Purdue University this semester (Spring 07). It is a challenging course for most graduate students. They come across many new concepts and many new terms. Among the most challenging are terms that refer to different classes of constitutive models that we may use to model different materials under different sets of conditions and that define, in a way, separate "branches" of continuum mechanics. They are the following:

  • Elasticity

  • Hypoelasticity

  • Hyperelasticity

  • Visco-elasticity

  • Visco-plasticity

  • Hypoplasticity

  • Plasticity

  • Hyperplasticity

I thought I would write briefly about each, without getting into mathematical formulations, to hopefully ease some of the difficulty.

An elastic material is a material for which the stress is uniquely determined by the strain. It is customary to define a natural, reference or unstrained configuration (one for which the strains are zero) for a body such that the stress for that configuration is zero.

An inelatic material is a material for which a unique relationship between stress and strain does not exist.

A hyperleastic material is one for which the stress is obtained from differentiation of a strain energy function wrt the corresponding strain. We are using stress and strain here to mean stress and strain components (components of the stress and strain tensors). This relationshipo between stress and strain follows from the equality of the integral of the strain energy function over any region R contained in the body to the internal potential energy in R.

A linear elastic material is a hyperleastic material with a quadratic strain energy function, such that stress and strain are linearly related.

A hypoelastic material is one for which a linear relationship exists between stress and strain time rates at a given value of stress. For every different stress value, the relationship changes. This allows consideration of path dependance and non-linearity in stress-strain response. However, a hypoelastic material does not follow the laws of thermodynamics (i.e., unloading the material to zero stress will not return it to its original state).

A hypoplastic material is also one for which a relationship exists between stress and strain time rates at a given value of stress but this relationship depends on more than jsut the current stress. Hypoplasticity can be viewed as a generalization of the concepts of hypoelasticity.

A hyperplastic material is one for which the first and second laws of thermodynamics are explicitly written as two state equations. One of the equations is a dissipative relationship (the energy dissipated during shearing or yield) that is obtained from a yield function in classical plasticity. In this case, it is possible to obtain a yield fuction from the dissipative relationship, the reverse of what is usually done.

A visco-elastic material is an inelastic material for which the inelastic strain is defined with basis on a rate equation. This rate equation expresses how the time rate of the strain varies with the applied stress. The relationship contains the viscosity (see Netson's law of viscosity for more on this).

A visco-plastic material is an inelastic material for which the inelastic strain is also defined with basis on a rate equation. The rate equation in this case is more general than for a visco-elastic material, storngly non-linear, with the possible existence of a yield surface separating elastic from inelastic response and the rate being directly related to the distance of the stress state from that yield surface on the inelastic side.

What is meant by a plastic material is a visco-plastic material for which changes in the rate of loading does not lead to changed response. Mathematically, this is handled by stating that the stress state is on the yield surface, and so the rate of loading is zero. The terms classical plasticity and rate-independent plasticity are also used.

Finally, a perfectly plastic material is one whose strength (whose yield surface) does not change upon shearing (i.e., the material neither hardens nor softens).

Friday, March 10, 2006

WSJ.com - The Numbers Guy

It seems that all the talk about how we are lagging behind in science in the U.S. may have some truth in it after all. This, from the WSJ, the "Numbers Guy", shows that even leading execs at tech companies could have used a probability class.


WSJ.com - The Numbers Guy: "Google Inc. reads, indexes and searches through billions of Web pages. On any given day, eBay Inc.'s more than 100 million members are listing millions of items for sale. Yet when it comes to the law of large numbers, executives at both tech powerhouses have committed statistical misdemeanors.

The law of large numbers says that the more times you measure something, the truer your results, and less they are affected by random variation. Flip a coin a million times, and you're likely to get heads half of the time (or very close to it). But flip that coin five times, and you might get heads four times, twice, or never.

But in corporate-speak, the 'law of large numbers' has been misused as a catch-all explanation for slowing growth as companies mature: It's harder to maintain high growth rates from a larger base. Last week, Google finance chief George Reyes told a Merrill Lynch & Co. investor conference that the company is 'getting to a point where the law of large numbers starts to take root.' (The Online Journal's MarketBeat column pointed out that Mr. Reyes meant the law of diminishing returns.) And in a January appearance on CNBC, eBay chief executive Meg Whitman said, 'Now, our businesses are getting larger and we will obviously face the law of large numbers, but we have actually changed the trajectory of the growth curve in our two largest businesses over the last three quarters." (She used the term correctly in a 1999 appearance on CNBC.) Several other executives have misused the term.

Misstating a statistics law isn't a federal offense, and lots of analysts make the same mistake when posing questions about disappointing earnings, in effect providing companies with an excuse for slow growth (reporters, including those at The Wall Street Journal, have also used the term incorrectly).

An eBay spokesman told me the term is "common corporate vernacular." Google declined to comment."


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The law of large numbers was propsed by Jacob Bernoulli in his "Art of Conjecture", which was published in 1713, 8 years after his death, after revisions done by his nephew Nicolaus. For more on Bernoulli and the law of large numbers, go here.

Wednesday, December 21, 2005

Best wishes for 2006!

We end the year among family, friends and colleagues in Brazil. I sat on a Ph.D. defense on the mechanics of unsaturated, collapsible soil. There is plenty of that in Brazil, and the precise modeling of these materials is still not possible, so it does offer its opportunities for research. I found our friends in Brazil quite active and was impressed with the faculty, program and students. In addition to visits with Adriano Bica, Luiz Bressani, Nilo Consoli and Fernando Schnaid, we spent some pleasant time with Beatrice Baudet and Matthew Coop, who were visiting from Europe. We are in discussions to have some of the students and faculty visit us at Purdue University for stimulating research.

As we come to the end of one each year, I try to reflect on what has passed, what I have learned from it, and what lies ahead. It is undeniable that things continue to move quite fast (faster than ever), and that we need to keep up or lose touch altogether. However, just as someone who drives at 120 miles an hour misses many of the details of the landscape and gets so focused on arriving that the joy of the trip is lost, the same can be said about life and everything that goes with it, including work. I believe strongly that if we are involved in activities that are right for us, we will do well, produce at rates we will be satisfied with, and enjoy greatly making the contributions we are sure to make. And the speed will feel right; it won't feel like 120mph. If the stress level is high, if we work more for awards or recognitions we covet and not for the joy of developing our talents and contributing to the world, something is amiss. So, most definitely, what I wish the most to all my friends and to visitors of this blog is that they find what they like and do well in life and that, in doing it, they find the greatest satisfaction of all: that of making contributions to friends, colleagues and society, of being of service. The exchange of ideas and experiences with others is another great source of satisfaction. While it is obviously gratifying to have our work recognized, it is also true that, in the history of science and engineering, it has often happened that recognition for significant contributions have not always come during someone's lifetime. That is only natural, for, as George Bernard Shaw once said, "All great truths begin as blasphemies." So if all the focus is on recognition, and one wants to find great truths, one may live in frustration an entire life!

Aside from our work as scientists and engineering, we deal with a lot more that goes along with it. We interact with people at all levels, and are therefore subject to the pressures from something psychologists referred to as "group think". In the words of one of the key researchers (Janus 1972) into this phenomenon: groupthink is "a deterioration of mental efficiency, reality testing, and moral judgment that results from in-group pressures." Experiments have shown how a person may state and even believe that a clearly shorter ruler is longer than a second one just because everyone else has said so (as directed by a researcher). Groupthink is one of the main reasons for many wrongs in this world, and will probably continue to be so. However, to be successful as professionals and human beings, we need the independence of thought. As Emerson put it: the great person is one who in the midst of the crowd keeps with perfect sweetness the independence of solitude. Independence of thought should be treasured in us and others. It is from diversity of knowledge, thoughts and opinions that most of what is good in life comes. As stated by Thoreau, "if a man does not keep pace with his companions, perhaps it is because he hears a different drummer. Let him step to the music which he hears, however measured or far away." In this light, let's enjoy the music, and let others enjoy theirs.

Happy 2006!


References:

Janis, Irving L. (1972). Victims of Groupthink, Houghton Mifflin Co., Boston.

Friday, November 25, 2005

What this blog is about

I intend this blog to focus on issues that are important to engineers, scientists and investors in technology. I will periodically discuss mechanics, design methods, software and a variety of science topics.

Thursday, November 24, 2005

Some Books Worth a Read

Gladwell, Malcom (2002). The Tipping Point. BackBay Books, 301 pp.
Goodman, Richard E. (1999).
Karl Terzaghi: The Engineer as Artist, ASCE.

The Power of Example

As an undergraduate student, I didn't rely on examples to learn new subjects. It is true that teaching at UFRGS in Brazil did not emphasize examples as much as we do in the U.S., but I leaned towards learning the fundamentals, learning the theory, and then solving problems only with that knowledge. I would, for example, learn calculus by studying the definitions and the theorems, including their proofs, but not spend time going through examples.

I later developed an appreciation for the power of example. This power comes through even in our language, as in "leading by example" and "monkey see monkey do" (a reference that some might find unflattering, although it is simply realistic, to our biological links to the champions of learning by mimicking). Consider a study by Prof. David Phillips of U.C. San Diego, as reported in Malcom Gladwell's excellent book, "The Tipping Point", that showed the strong correlation between number and nature of suicides and the appearance of front-page news of suicides in newspapers. Given the propensity of some to commit suicide by driving their cars onto something (including other cars), there was even a correlation between that type of news and the numbers of traffic accidents. And, not only that, but also between the type of suicide (suicide by a single person or murder of others followed by suicide) and the nature of the car accident (single-car or multi-car). So, in our lives, it is clear that example has a pervasive and powerful impact, for the good or for the bad.

Staying still in the world of science, example by influential individuals can set the course for a discipline for a long time. Being an engineer and a geotechnical engineer, I can comment on the history of my own discipline. The discipline came into existence to a large extent due to the efforts of an individual named Karl Terzaghi (for more on Terzaghi, there is a rather interesting biography of him written by Dr. R. Goodman, formerly of U.C. Berkeley). Early on, as Terzaghi was developing what would later become the theory of consolidation, a theory that aims to predict the rate at which saturated soils change volume, he was very keen about finding a suitable mathematical framework (what people sometimes refer to as "theory") for the results of his experiments. That continued for a time. But later in his career, more or less at the time of his conversion from primarily an academic to primarily a consultant, as a resident of the U.S. at the time, he started critizing theoreticians. Goodman's book has some interesting quotes that illustrate the earlier respect for and the later distaste for "theory". A respect for the underlying science and for the mathematics that allow for better predictions and calculations is healthy for the development of an engineering field, but Terzaghi's example caught on, and we still see today in the U.S. a bias towards the empirical and a certain disbelief in what "theory" can do for engineers. I believe this will change over the next years as the greater availability and quality of geotechnical software has been winning over the skeptics.

So examples are indeed important. As scientists, engineers or students, we use them to enrich a lecture, a paper or a book. In fact, when we provide something as evidence of the validity of an idea, hypothesis or theory, that something is often a good example of the validity or usefulness of the idea as well. But examples are far more than that. They can have wide and long-lasting effects on the way the world works.