150 anys després: des de l’Ictíneo (1859) fins a l’Ictíneo 3, un submarí modern per a treballs científics

El 1859, Narcís Monturiol va avarar el seu primer submarí a Barcelona. L’Ictíneo («peix vaixell», en grec) era un el·lipsoide de fusta d’olivera i coure dins d’un casc exterior. El submarí, de set metres de llarg i deu tones de desplaçament, podia encabir fins a sis persones i estava dissenyat per a profunditats de fins a cinquanta metres. El 1864 es va construir un segon Ictíneo, de disset metres de llarg i setanta-dues tones de desplaçament, que emprava un motor anaeròbic capaç de produir vapor per a la propulsió i oxigen respirable. En els dos vaixells, Monturiol hi va introduir solucions innovadores per aquell temps i el tractat que va escriure establia les bases per a la navegació submarina moderna. Després de cent cinquanta anys, l’empresa Ictineu Submarins està desenvolupant un submarí científic modern. Es submergirà fins a mil dos-cents metres i podrà acollir un equip de tres persones. S’anomenarà Ictíneo 3, en homenatge al seu antecessor

The Ictineu 3 project: A modern manned submersible for scientific research and intervention.

This paper describes the current state of Ictineu 3, the first project of Ictineu Submarins S.L., which aims at designing, building and operating a modern manned submersible for scientific research and intervention at a maximum depth of 1200m. This will be the first manned scientific submersible to be built and operated in the Iberian peninsula since the Ictíneo of Narcís Monturiol, and will help reduce the gap in our ocean exploration and intervention capabilities as well as pay a tribute to its old ancestor. This new submersible will employ state of the art technologies in areas such as material engineering, energy storage, navigation, control, and communication systems. Its main applications will range from deep seabed research, science dissemination, environmental protection, and archaeology to salvage operations and support to the offshore industry. The first sea trials are scheduled for the second half of 2010.Peer Reviewe

Unquenched lattice upsilon spectroscopy

A non-relativistic effective theory of QCD (NRQCD) is used in calculations of the upsilon spectrum. Simultaneous multi-correlation fitting routines are used to yield lattice channel energies and amplitudes. The lattice configurations used were both dynamical, with two flavours of sea quarks included in the action; and quenched, with no sea quarks. These configurations were generated by the UKQCD collaboration. The dynamical configurations used were ''matched'', having the same lattice spacing, but differing in the sea quark mass. Thus, it was possible to analyse trends of observables with sea quark mass, in the certainty that the trend isn't partially due to varying lattice spacing. The lattice spacing used for spectroscopy was derived from the lattice 1"1P_1 - 1"3S_1 splitting. On each set of configurations two lattice bare b quark masses were used, giving kinetic masses bracketing the physical #UPSILON# mass. The only quantity showing a strong dependence on these masses was the hyperfine splitting, so it was interpolated to the real #UPSILON# mass. The radial and orbital splittings gave good agreement with experiment. The hyperfine splitting results showed a clear signal for unquenching and the dynamical hyperfine splitting results were extrapolated to a physical sea quark mass. This result, combined with the quenched result yielded a value for the hyperfine splitting at n_f = 3, predicting an #eta#_b mass of 9.517(4) GeV. The NRQCD technique for obtaining a value of the strong coupling constant in the M-barS-bar scheme was followed. Using quenched and dynamical results a value was extrapolated to n_f = 3. Employing a three loop beta function to run the coupling, with suitable matching conditions at heavy quark thresholds, the final result was obtained for n_f = 5 at a scale equal to the Z boson mass. This result was #alpha#(5)/MS(Mz)=0.110(4). Two methods for finding the mass of the b quark in the MS scheme were employed. The results of both methods agree within error but the errors were too large to see any clear signal of unquenching in m-bar_b. The best result obtained was 4.42(33) GeV. (author)Available from British Library Document Supply Centre-DSC:DXN042099 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo