Archive for September, 2008

On John Stuart Mill

September 29, 2008

Adam Gopnik reviews a biography of John Stuart Mill by Richard Reeves; wherein, he refers to Mill’s work at East India Company, which I found interesting:

At the age of seventeen, he became a clerk at the East India Company, the private corporation that then ran India, and remained at its headquarters in London for thirty-five years, administering Indian affairs at a distance—a servant of British imperialism, but a benevolent kind. (When, later, the government tried to cut funds for Indian colonial colleges teaching Arabic and Sanskrit, Mill fought to keep the practice going, for fear of losing all contact with the élites. “Without knowing the language of a people, we never really know their thoughts, their feelings, and their type of character,” he wrote.)

Interesting piece; take a look!

A couple of articles on Delhi Iron Pillar

September 28, 2008

Prof. Bala is no stranger to this blog; nor are his pieces on archaeometallurgy; he alerts me about a couple of papers on Delhi Iron Pilalr that he published, recently, in Current Science.

The first one is about the materials science aspects of cannon ball impact on iron pillar (pdf):

The Delhi Iron Pillar was struck by a cannon ball with the specific aim of breaking the pillar into two. The history of the cannon ball strike has been traced briefly. The trajectory of the cannon ball has been established from the surface features of cannon ball indentation area as well as from the direction of shock wave propagation. The materials science aspects related to the pillar’s response to the cannon ball strike have been explained. The nature and origin of cracks surrounding the cannon ball indentation area have been analysed. Visual evidences have been provided to support the sequence of events that followed the cannon ball impact, in a time period of about a microsecond. These included intense plastic deformation leading to creation and propagation of plastic shock wave, initiation of crack at the rear, spallation of material, horizontal propagation of the main crack, and finally branching of the main crack along lump-lump interfaces. The analysis concludes that the fracture of the pillar was avoided by deflection of the propagating horizontal crack that originated from the rear end, diametrically opposite the cannon impact area, along the axial direction of the Pillar through the lump-lump interfaces.

As you might have guessed from the abstract, it might be of interest to the materials science oriented readers of this blog.

The second paper is on a sort of dimensional analysis of the Delhi Iron Pillar and the ratios of some of the numbers that appear in such an analysis (pdf):

The dimensions of the 1600-year-old Delhi Iron Pillar have been re-analysed in light of new scholarship on the traditional Indian unit of measurement. The dimensions of the pillar can be well reconciled considering the basic unit of measurement as 17.63mm. The low percentage errors between the theoretical and actual measurements provide further support to this analysis. The significant mathematical ratios embedded in the relative dimensions of the pillar have also been set forth. The close association of the basic unit of measurement and the mathematical ratios with those of the Harappan civilization offers evidence for continuity of scientific ideas and traditions from the Harappan civilization to the Ganga civilization. Analysis of the dimensions of the characters of the Gupta-Brahmi inscription revealed the possible use of the decimal system.

This paper might be of more general interest, and some of the reported results are very intriguing, to say the least.

Have fun!

Gandhi’s debt to Tagore

September 28, 2008

Guha in The Hindu on Gandhi-Tagore debates on nationalism (with a nice photo to boot):

Eighty years on, the Tagore-Gandhi debate still makes for compelling reading. The Mahatma insisted that a colonised nation had first to discover itself before discovering the world. The poet answered that there was a thin line between nationalism and xenophobia —besides, hatred of the foreigner could later turn into a hatred of Indians different from oneself (he was particularly sceptical of the claim that non-co-operation had or would dissolve Hindu-Muslim differences). Both men come out well; Tagore slightly better perhaps. He stood his ground, whereas Gandhi shifted his, somewhat. Pressed and challenged by Tagore, he broadened his nationalism to allow in winds from all parts of the world.

This, perhaps is not new to those who have heard Ram Guha on Tagore and Gandhi, or the readers of Ashish Nandy’s extraordinary book, The illegitimacy of nationalism. But, it still is a nice, short summary!

India’s greatest gift to itself (and the man who facilitated it)

September 27, 2008

Ram Guha in The Telegraph:

Back in 1957, Shankar’s Weekly had argued that along with the philosophy of Panchsheel, free elections were India’s greatest gift to Asia. No one believes in Panchsheel anymore, but electoral democracy has endured. It is, as it were, India’s greatest gift to itself. For while politicians in India are now anything but wise or patriotic, their misdeeds are kept somewhat in check by the mighty machine forged and welded by Sukumar Sen. Perhaps it is time that his fellow Bengalis properly honoured him. They might wish to name a major street in Calcutta after him. Or they might press the government of India to confer on Sukumar Sen a posthumous Bharat Ratna, to which his claims are far stronger than of some previous recipients of that award.

For the readers of India after Gandhi, Sukumar Sen might not be a stranger — but this is a nice, short piece with some more information on the man and his achievements; take a look!

Chabon on the American persidential election oratory

September 26, 2008

Chabon writes about his experience of attending the DNC in Denver and the role of spoken language and oratory in American politics (link via Laila Lalami):

The entire party convention is a collective act of that kind. It’s a throwback, a holdover, a relic, like baseball. It’s also, weirdly, a formal, public celebration of spoken language, a kind of political eisteddfod. A lot of the language I heard in the roughly thirty-seven speeches to which I listened was undoubtedly banal. The technique known as “staying on message”—picking one or two or at the most six things to talk about, and talking about them ceaselessly and in unvarying terms until they are no longer questioned, challenged, or even, really, remarked as they waft past the listener’s ear—is hell on poetry. The decimated vocabulary of modern American politics, confined to dwell on those islands called Family, Patriotism, Change, Future, and the Choices (Right and Dangerous), beggars most speeches down to their rhetorical rags and bones. In Denver the nearby presence of the Rockies tempted many of the speechwriters to pile up mountains of cliché.

Staying on message also tends to diminish the content of oratory. Most of the speakers offered up pretty much the same things, mutatis mutandi for region and generation and role in society, as those who preceded or followed them. The Message of a campaign is like a textured soy protein that appears at every meal in the guise of chicken or pork or the governor of Indiana, nutritious in its way but ultimately jading to the palate. “That is not the change we need,” Evan Bayh said, speaking of Senator McCain. And Amanda Kubik, a twenty-seven-year-old delegate from Fargo, North Dakota, said, “Barack Obama is the change we need.” In his acceptance speech, Joe Biden employed the phrase “that’s the change we need” five times in epistrophic succession.

I wondered if Obama ever wearied of the sham and extravagance and artifice. I wondered if his writerly ear rebelled at the nightly catalog of corn, platitudes, and dead language, or if perhaps the pragmatism so routinely underestimated by Obama’s opponents took satisfaction in the seamless forcefield of message generated nightly by the well-vetted objects of his speechwriters’ attentions. Or maybe, I thought, with his lyric grasp of US history, Obama enjoyed as much as I did the interstitial bits of procedural prose (“Ladies and gentlemen, fellow Democrats and friends, we bring you greetings from the great state of Georgia, the thirteenth state in our union, birthplace of Dr. Martin Luther King Jr….where we look to the future with an optimistic gaze…we, the empire state of the South, the jewel of the South, the great state of Georgia…), scenting the convention with their panatela reek of mock pomposity, the all but inaudible echoed trumpetings of the electoral past. Mostly, like everyone, I found myself wondering about the speech that he was going to give on Thursday night.

… Oratory demands not only stagecraft and poetry but the creation of a persona, and in this sense Michelle Obama’s speech carried twice the burden of any other speaker at the convention: she had to define herself, and in so doing, help to more sharply define her husband.

A very interesting piece; take a look!

Brad DeLong’s new guru!

September 26, 2008

Brad DeLong has a special self-smackdown edition:

For a decade now, I have been a follower of Greenspanism[1]–the doctrine that I name after former Fed Chair Alan Greenspan that the constraint on expansionary monetary policy is inflation and inflation alone. The idea is that the first priority of the central bank is to maintain low consumer price inflation, and that the second priority is–given low current and forecast consumer price inflation–to maintain maximum employment and purchasing power–and the third priority of the central bank is that there is no other third priority.

Opposing Greenspanism is what I call Mussaism[2]. Mussaism–the doctrine I name after former IMF Chief Economist Michael Mussa–holds that there are two constraints on central bank activity. The central bank must insure:

  1. No large asset bubbles.
  2. Consumer price stability.

Only after it has successfully achieved these two higher priorities can it then even begin to worry about:

(3) Maximum employment and purchasing power.

The Greenspanist retort to the Mussaites–a retort I would have said I believed 100% a year and a half ago, 90% a year ago, and 60% last March–is that creating unemployment and idle factories because you are scared of what might happen when irrational exuberance dies away and asset prices collapse is a crime; that modern central banks are powerful; that they can successfully manage whatever crisis is provoked when it happens; and that it is easier to sweep after the elephants have gone through than to try to stop them–especially when stopping them requires the destruction of millions of jobs.

I don’t see how I can maintain my belief in Greenspanism today[3].

Therefore I abjure, I recant, and I do penance. I transfer my allegiance and fealty to Michael Mussa, who is my new guru.

By the way, that I read blogposts like this is what makes me take offence when I see sentences like this (especially from a blogger for whom I have plenty of respect):

Could this be circumstantial evidence that economics, while dismal, is not a science? Otherwise, an economist would just assume that oversight would be part of the deal, right?

    Ultrasmooth mirrors for a new microscope

    September 25, 2008

    Nature News reports that a new ultrasmooth mirror could herald the birth of a new microscope:

    Electron microscopes can produce highly magnified images, but they have serious drawbacks. The samples must conduct electricity; electrons penetrate into the sample, leading to an image that doesn’t accurately represent the surface; and, worst of all, the very-high-energy electron beams can obliterate the precious samples.

    An atomic microscope with a low-energy beam of helium atoms could get around these problems. Neutral helium can bounce off any surface, conducting or insulating, and the beam would be deflected by the electrons at the very edge of the sample, giving a true image of the surface. But an atomic microscope demands a focused beam of helium atoms — and that requires a mirror that reflects the beam with very little scattering of the atoms.

    A metal coating would reflect and focus helium much more tightly, but metals grown on silicon tend to clump into islands that scatter incoming atoms in all directions. “The point is to try to reproduce the perfection of the underlying surface,” says Miranda.

    Miranda managed this by exploiting a quantum stabilization effect previously seen in ultrathin lead films. For certain thicknesses of lead, the metal’s electrons can sit in very stable energy levels so that, under the right conditions, the surface simply smooths itself out to a continuous thickness.

    The resulting 2-centimetre-wide flat mirror is atomically smooth, even after it has warmed up to room temperature, and it can reflect 15% of incoming helium atoms.

    A very interesting piece; take a look!

    Research Ethics and Project Proposal Reviews

    September 24, 2008

    Dr. Free-Ride at Adventures in Ethics and Science has a must-read essay (which, I understand is the first in a series of two posts) on research ethics:

    In the U.S., the federal agencies that fund scientific research usually discuss scientific misconduct in terms of the big three of fabrication, falsification, and plagiarism (FFP). These three are the “high crimes” against science, so far over the line as to be shocking to one’s scientific sensibilities.

    But there are lots of less extreme ways to cross the line that are still — by scientists’ own lights — harmful to science. Those “normal misbehaviors” emerge in a 2006 study by Raymond De Vries, Melissa S. Anderson, and Brian C. Martinson [1]:

    We found that while researchers were aware of the problems of FFP, in their eyes misconduct is generally associated with more mundane, everyday problems in the work environment. These more common problems fall into four categories: the meaning of data, the rules of science, life with colleagues, and the pressures of production in science. (43)

    This rather lengthy post discusses the first two aspects of misbehaviour stated above, namely, meaning of data and rules of science, and as I said, is a must-read. I look forward to the next piece in the series.

    Drug Monkey tackles the question, namely, whether junior reviewers are too focussed on details while reviewing project proposals, and whether such obsession with details, if any, affects the reviewing process and quality (well, the short answers are may be and no):

    The argument against the more-junior reviewers on NIH study section review that is the most amenable to discussion is that the younger people are unable to see the forest for the trees. Unable to take the broad view. Have a tendency to focus on details and grantsmanship issues in preference to the quality of the science (wot, wot?). I will note the evidence for this is quite lame, as there are never any studies or CSR datasets being referenced. What I do hear generally follows the following trends.

    1. The comically flawed assumption that the PI in question knows which of the critiques of their grants were written by less-tried investigators.
    2. The perspective of the PI’s experience with the (1?, 3?) Assistant Professors in their Department who give them informal comments on their own grant.
    3. Occasionally some direct study section experiences in which it is claimed that the Assistant Professors focus on detail too narrowly.

    For argument’s sake, let us credit these observations and ask why this might be the case.

    Take a look!

    Update: The second part of Dr. Free-Ride’s post is also up. Needless to say, a must-read too.

    Deformation of metal micropillars

    September 24, 2008

    Sometime back, I linked to an article on the mechanisms of plasticity in Ni pillars under compression, and how the dislocation starvation in these systems leads to higher yield strengths. I understand that there is also a competing model which attributes the strengthening of micropillars to the internal pinning points and their effect on dislocation propagation.

    In a recent paper in PNAS, C R Weinberger and W Cai try to resolve this controversy by trying to answer a more basic question, namely, how does a single dislocation, once nucleated move inside the micropillars.

    Weinberger and Cai use computer simulations to study dislocation propagation in micropillars with FCC and BCC crystal structures and show that the crystal structure has a crucial role to play; here are their conclusions:

    In summary, we discovered a new mechanism in which a single dislocation can multiply itself repeatedly in a BCC micropillar but not in an FCC micropillar. The mechanism is the combined result of both the surface-induced image stress and surface-dominated dislocation mobility at small scales. This discovery points to the necessity of different interpretations for the size-dependent yield stress on FCC and BCC micropillars. It also points to the importance of carefully accounting for surface effects on both the stress field and dislocation mobility in the dislocation dynamics modeling of plasticity at the microscale.

    The paper, titled Surface-controlled dislocation multiplication in metal micropillars is available here ; and, here is the abstract:

    Understanding the plasticity and strength of crystalline materials in terms of the dynamics of microscopic defects has been a goal of materials research in the last 70 years. The size-dependent yield stress observed in recent experiments of submicrometer metallic pillars provides a unique opportunity to test our theoretical models, allowing the predictions from defect dynamics simulations to be directly compared with mechanical strength measurements. Although depletion of dislocations from submicrometer face-centered-cubic (FCC) pillars provides a plausible explanation of the observed size-effect, we predict multiplication of dislocations in body-centered-cubic (BCC) pillars through a series of molecular dynamics and dislocation dynamics simulations. Under the combined effects from the image stress and dislocation core structure, a dislocation nucleated from the surface of a BCC pillar generates one or more dislocations moving in the opposite direction before it exits from the surface. The process is repeatable so that a single nucleation event is able to produce a much larger amount of plastic deformation than that in FCC pillars. This self-multiplication mechanism suggests a need for a different explanation of the size dependence of yield stress in FCC and BCC pillars.

    Take a look!

    Ross, Adichie — among MacArthur 2008 fellows

    September 23, 2008

    Via Maud; here is the Foundation page with the announcement. Another interesting fellow I noticed is Marin Soljocic:

    Optical Physicist demonstrating both theoretically and experimentally that power can be transmitted wirelessly, potentially leading to a range of electrical devices that can operate without batteries or wall connections.

    Take a look!