WobLog

Catching up on old magazines, I caught an article in the August 2008 issue of Physics Today on the physics behind Speedo's LZR Racer swimsuits, which made such a big "splash" at the 2008 Olympics:

Competition in the pool at this month's Beijing Olympics will be not only among world-class swimmers but also their swimsuits. Since its debut in February, the low-drag hydrophobic Fastskin LZR Racer swimsuit from Speedo International Ltd has had more than 44 world records broken in it; critics allege that the $600 "space-age" suit, in part developed by NASA scientists, gives its wearers an unfair boost in buoyancy and amounts to "technological doping." The company claims a 5% decrease in drag over the previous model but no buoyancy increase, and the suit, along with competing models, has been approved for Olympic competition by FINA, the international swimming federation.

The LZR Racer is a descendant of the full-body swimsuit Speedo introduced in 2000 to mimic the viscous-drag-reducing denticles on a shark's skin. The shark suit proved that surface-engineered synthetic materials can be made to have lower drag than a swimmer's shaved skin. The next move for Speedo's internal R&D unit was to form a team of external partners led by Barry Bixler, the late Honeywell Corp engineer and computational fluid dynamics (CFD) expert, to further cut the passive drag.

[...]

"There is still debate as to what the primary source of drag is for a shark, but for a swimmer, it is primarily form drag," says Amy Lang, an experimental fluid dynamicist at the University of Alabama. From CFD simulations and studies in a swimming flume, the researchers determined that total drag is reduced when low-drag polyurethane panels are inserted to compress the chest, upper thighs, and other areas of the swimmer's body where form drag is most pronounced. "We spent a lot of time [on the previous model] drag testing anatomically accurate mannequins" in the flume, says David Pease, a biomechanist at the University of Otago in New Zealand. "This time around involved quite a bit more actual athlete testing in order to test differences in compression and support provided by the new suit."

The article goes on to describe some of the work going on in preparation for the 2012 Olympics, extending research from minimizing drag during the glide phase of a stroke to include combating drag during the active phase of each stroke.

Posted by Don Roberts at 10:10 PM | Permalink | Comments (0)

Michael Phelps appeared Thursday night, December 11 on FOX News' Hannity & Colmes to talk about his new book, No Limits: The Will to Succeed. He talked about his childhood ADHD and about how many calories a day he really eats. You can watch the interview at FOXNews.com

Posted by Don Roberts at 7:10 AM | Permalink | Comments (0)

We all know that windmills kill birds. Now even some homes are not safe:

Ice-Tossing Turbines: Myth or Hazard?

By KATE GALBRAITH, New York Times

How do wind turbines fare in winter weather?

Not so well, according to one little town in England. The Wisbech Standard reports a harrowing tale in which "lumps of ice three or four feet long flew through the air" and smashed into a carpet showroom and a parking lot.

They apparently came off the spinning blades of a 410-foot-tall wind turbine.

[...] a 2006 publication by G.E. Energy, a maker of large wind turbines, warns that "rotating turbine blades may propel ice fragments some distance from the turbine -- up to several hundred meters if conditions are right."

Posted by Don Roberts at 12:51 PM | Permalink | Comments (0)

I recently upgraded our blog software to the latest version of MovableType (v.4.23). Not a painless process, and I'm not done yet. To take full advantage of the new version's capabilities, I need to upgrade all our blog templates. That won't happen for a while.

Anyway, the new blog software broke the old CAPTCHA module that I'd been using (SCode). However, the new one (reCAPTCHA) has a nice benefit: its CAPTCHA's come from digitized books. It uses words that were not recognized by OCR software. Basically, everyone who uses this module is helping to get books into digital form. Cool, huh?

Posted by Don Roberts at 4:05 PM | Permalink | Comments (1)

Over at the New Liturgical Movement, they have an interesting entry on the origin of the Christmas carol "O Come, O Come, Emmanuel"

The well-known Advent hymn O Come, O Come, Emmanuel belongs to the ever-growing repertoire of popular hymns known, loved, and sung all over the English-speaking world. It made its first appearance as far back as 1854, in Part II of the Hymnal Noted, edited by Thomas Helmore. The English words are based on a free Latin paraphrase of the great O Antiphons, which are sung with the Magnificat at Vespers on the days leading up to Christmas Eve. These antiphons themselves came into existence at least as early as the eighth century. The paraphrase can he traced back to the seventh edition of the Psalteriolum Cantionum Catholicarum, published in Cologne in 1710. The present splendid English translation was made by Thomas Alexander Lacey (1853-1931) for the English Hymna1 (1906), of which he was joint editor.

The familiar melody was said by Thomas Helmore to have been "copied by the late J. M. Neale from a French Missal" which he located “in the National Library, Lisbon." But in a letter to the press in 1909, H. Jenner claimed that his father, Bishop Jenner, had copied both the tune and the words in Lisbon in 1853. All attempts to track it down, however, failed: neither a "French Missal," nor indeed any service-book from Lisbon could be produced to justify either claim. The compilers of the 1909 historical edition of Hymns Ancient and Modern drew a complete blank, and, more recently, one scholar even made the ingenious suggestion that Thomas Helmore had perhaps composed the tune himself, coyly hiding his identity behind the pretence that it was an ancient tune gleaned from a Continental source.

I was able, however, in 1966, to vindicate his honor. My attention had been drawn to a small fifteenth century processional in the Paris Bibliothèque Nationale. It was Franciscan in origin and probably intended far the use of nuns rather than friars. Turning the pages I discovered, on folio 89v ff, a number of troped verses for the funeral responsory Libera me in the form of a litany, beginning with the words "Bone iesu, dulcis cunctis.” The melody of these tropes was none other than the tune of O come, O come Emmanuel. It appeared in square notation on the left-hand page, and on the opposite page there was a second part that fitted exactly, like a mirror-image, in note-against-note harmony with the hymn-tune. The book would thus have been shared by two sisters, each singing her own part as they processed.

So it would seem that this great Advent hymn-tune was not, in the first instance, associated with Advent at all, but with a funeral litany of the saints in verse, interspersed between the sections of a well-known responsory. Perhaps it is a measure of Helmore's genius that he detected in this melody an appropriate Advent sound as well, one which conveys an unmistakable sense of solemn expectancy, not only for the Nativity of Christ, but also for his Second Coming as judge and as savior. Helmore was shrewd enough, also, to have been aware that an indubitable link exists between the theology of Advent and a procession marking the passage from death to eternal life.

Posted by Don Roberts at 10:45 AM | Permalink | Comments (2)