A term in oceanography: brinicle for a salty ice stalactite

The term brinicle immediately raises associations with the words brine and icicle: a brinicle looks like an icicle and forms in cold or icy solutions of salt in water. Due to the fluid mechanics of cold, freezing seawater the overall form of a brinicle resembles more the shape of a tornado funnel than that of a straight, downward-pointing icicle.

Jeremy Berlin describes a brinicle descending about seven feet from the surface ice in antarctic waters, which was filmed by two British cameramen as it formed [1].  Ice stalactites look like they are out of a science fiction novel or computer animation, but they occur for real. American oceanographers Paul Dayton and Seelye Martin described them in 1971. Brinicles were successfully generated in a laboratory study by injecting cold, dense brine into an insulated tank of sea water held at its freezing point [2]. 

Sea water in polar regions, freezing at the ocean surface, can concentrate brine entrapments to very high salinities. Such brine pockets, which can have complex geometries, result into drainage tubes. When conditions are right, high-salinity drainage may descend as brine plume, “forming long, delicate, thin-walled hollow ice stalactites that on occasion can extend up to 6 m below the bottom of the sea ice ...” [3]

Brinicles are too slow forming to freeze anything in. There is no danger to submarines [1]. Brinicles are fragile and can be broken apart by currents as well as seals and divers. 

Keywords: fluid dynamics, frigid waters, seawater, dense brine.

References and more to explore
[1] Jeremy Berlin: In the frigid waters of Antarctica, briny tubes of ice can stretch down to the seafloor. National Geographic May 2012, 221 (5), pp. 30-31.
[2] Martin Seelye: Ice stalactites: comparison of a laminar flow theory with experiment. Journal of Fluid Mechanics 1974, 63, pp. 51-79. DOI: 10.1017/S0022112074001017.
[3] Austin Kovacs: Sea Ice. Part I. Bulk Salinity Versus Ice Floe Thickness. US Army Corps of Engineers - Cold Regions Research & Engineering Laboratory, CRREL Report 96-7, June 1996; Figure 3 [www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA312027].

Tourmaline: a gemstone name with Singhalese roots

The gemstone name tourmaline is though to derive form a Singhalese (Sinhalese, Cingalese) word or a variant thereof: turmali, tourmali, turamali, thuramali and thoramali are some of its spellings that can be found in the literature, buyer's guides and on websites [1-5]. The name means “mixed parcel,” referring to the large variety of color combinations in which its gemstone specimens occur [3,4]. Originally, the term tourmaline was applied to zircon and other gems by jewelers of Ceylon (now Sri Lanka) [5].

Localities for tourmaline specimens include places in Asia, Europe, Africa, North and South America and even Antarctica (map in [2]). Dutch traders, shipping tourmaline stones from Sri Lanka to Europe, called them Aschentrecker (“ash puller”) due to their pyroelectric properties [1]. Tourmaline is also thought to be identical with lyngurium, described by the ancient Greek scholar Theophrastus of Eresus  (c. 371-285 BC) in his work on stones, De lapidibus,—mistaken as solidified lynx urine.

Classified as a semi-precious stone, tourmaline actually comes in different species and varieties. The Dictionary of Geology and Mineralogy [6] defines tourmaline as “any of a group of cyclosilicate minerals with a complex chemical composition, vitreous to resinous luster, and variable color, crystallizes in the ditrigonal-pyramidal class of the hexagonal system, has piezoelectric properties, and is used as a gemstone.” The dictionary gives the general formala,

(Na,Ca)(Al,Fe,Li,Mg)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄,

which has to be modified to a more specific one when particular species are considered. To better understand the crystal structure of tourmalines, one may, for example, consult the CrystalMaker®-generated drawings by  Darrell Hennry and Barbara Dutrow (page 20 in [1]), depicting structural features of one of the most common tourmaline species, schorl (NaFe²⁺₃,Al₆Si₆O₁₈(BO₃)₃(OH)₃OH). Their figures demonstrate ion and polyhedra arrangement and, in particular, the cyclosilicate-coordinated structure based on rings of six SiO₄ tetraeder (the Si₆O₁₈ unit in the formula). Further, these authors explain the composition and color zoning structure of tourmalines and their significance as forensic objects in earth science and natural history. 

Keywords: geology, mineralogy, gemstones, lapidary, crystal morphology, linguistics, terminology.

References and more to explore
[1] Darrell J. Henry and Barbara L. Dutrow: The Tourmaline Diaries. Natural History March 2012, 120 (3), 16-27.
[2] mindat.org: Tourmaline [www.mindat.org/min-4003.html].
[3] Richard W. Hughes: Palegems.com Tourmaline Buying Guide [www.palagems.com/tourmaline_buyers_guide.htm].
[4] gemselect.com: Tourmaline's name... [www.gemselect.com/gem-info/tourmaline/tourmaline-info.php].
[5] Richard Scott Mitchell: Mineral Names. What do they mean? Van Nostrand Reinhold Company, New York, 1979; page 192.
[6] Dictionary of Geology & Mineralogy. Second Edition. McGraw Hill, New York, 2003.

Lyngurium, meaning solidified lynx urine

The term Lyngurium means “solidified lynx urine.” Lyngurium was first mentioned by the Greek philosopher and naturalist Theophrastus of Eresus (c. 371-285 BC) in his work on stones, De lapidibus, in which he described the origin of a mineral by solidificaton of urine—preferably from a wild, male lynx [1,2]. This mineral is today known as tourmaline.

The false folklore believing in a gemstone made of frozen lynx urine was passed on into the Middle Ages. How do we (think we) know that Theophrastus was actually referring to tourmaline? Steven Watson puts it this way [1]:

Modern consensus assigns the name lyngurium to some form of clear amber or else a type of tourmaline, given its yellow colour and well-known static elctrical properties, even though Theophrastus says it is like amber, implying that it is not amber, and despite the fact he discusses the two stones in two clearly distinct sections of De lapidibus. Such ‘rationalist’ attempt at identification need not concern us here, since our interest is not in what the stone lyngurium was, but, rather, how and why knowledge about it was transmitted from the classical world to the Middle Ages and Renaissance.

Being concerned what lyngurium was, most scientists stick with the alternate possibility. The alternative to ruled-out amber is tourmaline, based on the unusual properties (“unusual powers”) that Theophrastus attributed “his lynx-stone” with.

Keywords: geology, ethnomineralogy, gemstones, lapidary, folklore, misconception, knowledge transfer, philosophy.

References and more to explore
[1] Steven A. Walton: Theophrastus on Lyngurium: Medieval and Early Modern Lore from the Classical Lapidary Tradition. Annals of Science 2001, 58, pp. 357-379 [pennstate.academia.edu/StevenAWalton/Papers/576107/Theophrastus_on_lyngurium_Medieval_and_early_modern_lore_from_the_classical_lapidary_tradition].
[2] Darrell J. Henry and Barbara L. Dutrow: The Tourmaline Diaries. Natural History March 2012, 120 (3), 16-27.

Mobart, Tasmania

You won't find Mobart on a traditional map of Tasmania. But this nickname rhymes with the name of the capital of the Australian island state of Tasmania: Hobart (founded in 1804 as a British penal colony). The name Mobart is a play on Hobart's current transformation from a quiet down-under town into a hip and sexy destination offering performing and provoking arts, including the nearby Wunderkammer complex called Museum of Old and New Art (MONA) [1-3].

“A decade ago, Tasmania had no pulse, but now young people are staying.” says Christine Scott, curator at Hobart's Henry Jones Art Hotel (page 39 in [1a]). The national parks and reserves of Tasmania have attracted outdoor adventurers for a long time. Bushwalking and wilderness challenges can now be complemented by museum walking and experience of offbeat culture—in town and on the banks of the Derwent River, where the MONA is located.

The man behind the MONA, millionaire David Walsh, calls his museum “a subversive adult Disneyland.“ (page 39 in [1a]). The emphasis is probably not as much on “Disneyland“ as it is on “adult.“ MONA offers after-hours naked tours through the maze of artworks to confront the depictions on a raised level of alert and excitement. However, don't get undressed yet. There is a waiting list!

Thinking history, say Hobart. Thinking museum, say Mobart. Thinking nudity, say Nobart! 

Keywords: Australia, museology, hipster renaissance, entertainment, curiosity.

Note:  The art world loves playing with words, spelling and writing. Not only down under, but in every city with suitable urban space,  MobArt, may pop up. MobArt is an art gallery with a twist; it's mobile as suggested by the name: www.mobartgallery.com. The next MobArt show may happen in Hong Kong, [H,M,N]obart or in your town.

References and more to explore
[1] Tony Perrotet: (a): Tasmania's New Devil. Smithsonian Magazine May 2012, pp.36-48; (b) Nudity, Art, Sex and Death - Tasmania Awaits You: www.smithsonianmag.com/travel/Nudity-Art-Sex-and-Death-Tasmania-Awaits-You.html.
[2] Drew Martin: Holy Shit Tasmania! April 21, 2012 [museumofperipheralart.blogspot.com/2012/04/holy-shit-tasmania.html].
[3] Video tour: ArtBreak MONA,  Australia's largest privately owned gallery, breaking convention by exhibiting old and new art alongside each other rather than chronological order [www.youtube.com/watch?v=nNe1sfcsd8c].

Sarcodes sanguinea: scientific name for snow plant referring to texture and color

Sarcodes sanguinea is the scientific name for the snow plant or snow flower, which is a parasitic plant in the heath family (Ericaceae), found in Oregon, California and northwest Nevada. The genus name Sarcodes derives from the Greek word sarx for “flesh” and oeides for “like,” describing the snow plant's flesh-like texture. Its deep red color is denoted by the Latin word sanguinea, meaning “blood-red.” The brilliant red makes the snow flower unforgettable, once seen on the forest floor between coniferous trees, through which the rays of sunlight may break their path to the plant that is unable to use them for photosynthesis.  

Since the snow plant is the only member of  the genus Sarcodes, it is sometimes simply mentioned by its genus name, especially in foreign languages. Species and genus was first described by John Torrey in 1853; hence the extended scientific name Sarcodes sanguinea Torr. John Torrey (1796-1873) was an American botanist.

More about the snow plant
In English: Snow plant (Sarcodes sanguinea).
In German: Schneepflanze (Sarcodes sanguinea).

Nomenclature references
Sarcodes: Sarc'odes.
sanguinea: sanguin'ea/sanguin'eum/sanguin'eus.
John Torrey:  Encyclopedia Britannica: Torrey, John.

The names of moon rovers

Red Rover, Euroluna, JURBAN, Odyssey Moon, Synergy Moon, Italia, Puli Space and White Land Space are just a few names for moon rovers. In fact, they represent ambitious projects of designing and building rovers to compete in the Google Lunar X PRIZE (GLPX), also called Moon 2.0 [1-4]. To win, a participating team has to get its moonbot to the lunar surface by 2015 and guide it around. Sponsored by Google and organized by the X Prize Foundation, you will not be surprised that successful moon missions have to send images and other data back to Earth: from moonbot to Googlebot. Teams are from Brazil, Canada, Chile, China, Denmark, Germany, Hungary, Malaysia, the Netherlands, India, Israel, Italy, Russia, Spain and the United States of America.

 Not only is there a diverse mix of competitors, but also a diversity in design and technology. The Hungarian Puli Space rover with its dreadlocks, for example, looks like a sea urchin. The approximate radial symmetry will allow the Puli Space rover to conquer moon territory by rolling around via its flexible spines [5]. Another interesting approach is the swarm-bot design of  JURBAN with its individually moving parts that can line up and form a robotic earthworm [6]—better call it moonworm! The Jurban team, comprised of high school to doctoral students, designed redundancies in each of the semi-autonomous segments, such that, if one part fails, the swarm or centipede-like moonworm can split up, rearrange and still operate.

What a change from the 1960s and 1970s when only Soviet and US space invaders were competing cold-war style. Back then, the Soviet remote-controlled lunar rover named Lunokhods was the only robot that survived the temperature extremes on the moon, where surface temperatures can change from 248 degrees Fahrenheit at daytime to -274 deg. F. at night [4]. Planning a successful mission to and on the moon is not just rocket science, but materials science as well.     

In case you want to follow the ranging rovers you should be able to: they will send e-mails, twitter about their twists and targets and also post on Facebook. It is time to make the rovers your friends.

Keywords: astrobotics, lunabotics, moonbots, rocket science, engineering, terminology.

References, inspirations and more to explore
[1] Google Lunar X PRIZE: www.googlelunarxprize.org/.
[2] Wikipedia: Google Lunar X Prize [en.wikipedia.org/wiki/Google_Lunar_X_Prize].
[3] X Prize Foundation: Google Lunar X PRIZE Announces Official Roster of Teams Competing in the $30 Million Race to the Moon. February 17, 2011. Listing of  29 participants: www.xprize.org/press-release/google-lunar-x-prize-announces-official-roster-teams-competing-30-million-race-moon.
[4] Michael Belfiore: Bound for the Moon. Scientific American April 2012, 306 (4), pp. 54-59. Also see: Shooting for the Moon [http://www.scientificamerican.com/article.cfm?id=x-prize-astrobotic-gallery].
[5] Watch the Puli Space urchin rolling on the moon source with Hungarian Rhapsody music: www.youtube.com/watch?v=tSrAR_Gtaa4.
[6] Don't Count Out GLXP Team JURBAN: www.marstravel.org/2012/01/dont-count-out-glxp-team-jurban.html.

Acronym in mathematics: AM-GM for arithmetic-mean/geometric-mean

The mathematical acronym AM-GM for arithmetic-mean/geometric-mean is frequently used while referring to the AM-GM inequality. The “means” are defined as

A_n = (x₁ +...+ x_n)/n   and   
G_n = (x₁ ⋅...⋅ x_n)^1/n

for all  x_k ≥ 0. The AM-GM inequality states that

A_n ≥ G_n .

The AM-GM equality is sometimes called the Cauchy inequality. In a recent note, Lech Maligranda shows that the AM-GM inequality is equivalent to what now is called the Bernoulli inequality [1]. The latter was proved in the 17th century by Isaac Barrow and Jacob Bernoulli:

xⁿ ≥ 1 + n(x - 1)

for any natural number n  and x > 0.

Our acronym expands to AM-GM-HM, when the harmonic mean (HM or H_n) is included. In the AM-GM-HM inequalitiy the “means”are related as follows [2]:

  A_n ≥ G_n  ≥ H_n .

Keywords: mathematics, statements, relationships, inequalities, equivalence.

References and details
[1] L. Maligranda: The AM-GM Inequality is Equivalent to the Bernoulli Inequality. The Mathematical Intelligencer 2012, 34 (1), page 1. DOI: 10.1007/s00283-011-9266-8.
[2] Physics Forums > Mathematics > Calculus/Analysis > Inequalities > AM-GM-HM inequality: www.physicsforums.com/library.php?do=view_item&itemid=14.

Note: the harmonic mean is defined as

H_n = n/(1/x₁ +...+ 1/x_n).