High-energy neutrinos from a lunar observatory

The detection of high-energy (HE) cosmic and solar-flare neutrions near the lunar surface would be feasible at energies much lower than for a terrestrial observatory. At these lower energies ( 10 to the 9th eV), the neutrino background is drastically reduced below that generated by cosmic rays in the Earth's atmosphere. Because of the short mean free path ( 1m) of the progenitor pi and K mesons against nuclear interactions in lunar rocks, the neutrino background would be quite low. At 1 GeV, less than 1% of the pions would decay; at 10 GeV, 0.1%. Thus, if the neutrino flux to be observed is intense enough, and its spectrum is steep enough, then the signal-to-noise ratio is very favorable. The observation of HE neutrinos from solar flares would be dramatically enhanced, especially at lower energies, since the flare spectra are very steep. Detection of these neutrinos on Earth does not appear to be feasible. A remarkable feature of solar flares as viewed in HE neutrinos from a lunar base is that the entire surface of the Sun would be visible

Standoff Detection via Single-Beam Spectral Notch Filtered Pulses

We demonstrate single-beam coherent anti-Stokes Raman spectroscopy (CARS), for detecting and identifying traces of solids, including minute amounts of explosives, from a standoff distance (>50 m) using intense femtosecond pulses. Until now, single-beam CARS methods relied on pulse-shapers in order to obtain vibrational spectra. Here we present a simple and easy-to-implement detection scheme, using a commercially available notch filter, that does not require the use of a pulse-shaper.Comment: 3 pages, 3 figure

Impact of carbon dioxide on Ivanić oilfield in tertiary oil recovery phase

Godišnja proizvodnja nafte u Hrvatskoj s više od 30 naftnih polja je nešto veća od 500 000 tona. Tijekom proteklih 50 godina iz naftnih ležišta u Hrvatskoj ostvaren je prosječan iscrpak nafte od 32,6% utvrđenih rezervi nafte. Sadašnja cijena nafte na svjetskom tržištu potencira primjenu tercijarnih metoda povećanja iscrpka nafte. Ukoliko se iz postojećih ležišta nafte u Hrvatskoj uz te metode poveća iscrpak nafte za 3%, to dovodi do povećanja godišnje proizvodnje od 15 000 tona nafte. U svjetskoj praksi sve zastupljenija je proizvodnja nafte tercijarnim metodama pri čemu utiskivanje ugljičnog dioksida u naftna ležišta ima najveću primjenu. Na temelju laboratorijskih ispitivanja primjene tercijarnih metoda povećanja iscrpka iz naftnih ležišta u Hrvatskoj utiskivanje ugljičnog dioksida je odabrano kao najpovoljnija metoda povećanja iscrpka nafte iz ležišta naftnog polja Ivanić. Tijekom utiskivanja ugljičnog dioksida u naftno ležište mijenja se njegovo agregatno stanje iz kapljevitog u plinsko ili pregrijano stanje. Mjereni podaci o ugljičnom dioksidu u laboratorijskim uvjetima i uvjetima utiskivanja u ležište nažalost odstupaju. S obzirom na to da su mjerenja u bušotinskim uvjetima skupa, a neki puta i tehnološki neizvediva, za poznavanje stanja ugljičnog dioksida u bušotinskim uvjetima uzimaju se različite aproksimacije uz upotrebu raznovrsnih jednadžbi stanja. Izmjereni podaci o faznom stanju ugljičnog dioksida u širokom rasponu p,T uvjeta tijekom njegova utiskivanja u ležišta naftnog polja Ivanić tijekom pilot projekta željeli su se aproksimirati nekom od brojnih jednadžbi stanja i ne mogu se na nekom drugom ležištu koristiti. Od brojnih kubičnih jednadžbi stanja odabrane su van der Waalsova, Redlich-Kwongova, Soave-Redlich-Kwongova, Peng-Robinsonova, Valderrama-Cisternasova, Patel-Tejina, Lawal-Lake- Silberbergova i Martin-Houova jednadžba. Nakon sveobuhvatne analize mjerenih i računatih vrijednosti u širokom rasponu p,T uvjeta preporučene su jednadžbe stanja za proračunavanje faznih stanja ugljičnog dioksida kod njegova utiskivanja u ležišta naftnog polja Ivanić.Current annual oil production in Croatia on more than 30 oilfields, amounts to a little more than 0.5 million t per year. In the last 50 years, the realized oil recovery factor from the oil reservoirs has on average amounted to 32.6% of original oil in place. The currently favourable oil price increases the need for higher oil recovery from existing oilfields through the implementation of tertiary oil recovery methods. As for Croatia, a 3% increase in the oil recovery factor from current oil reservoirs, obtained due to the implementation of tertiary oil recovery methods, increases annual oil production by 15 000 t. Although tertiary oil recovery methods (EOR methods) are becoming more common worldwide, carbon dioxide injection in oil reservoirs is the most implemented EOR method. Based on the laboratory test results of the applications of tertiary oil recovery methods on oil reservoirs in Croatia, the carbon dioxide injection process was chosen as an appropriate method for increasing oil production on the Ivanić oil field. During the injection stage, carbon dioxide changes the state of the matter from liquid to gaseous or supercritical state. Unfortunately, the measured carbon dioxide injection results and laboratory test results differ. In situ measurements are very expensive and sometimes impractical; therefore, various approximations are taken into account with numerous equations of state. The aim was to approximate an equation of state on the measured data, for a wide range of p,T conditions, during a pilot project of carbon dioxide injection on the Ivanić oilfield reservoir. Among numerous cubic equations of state, van der Waals, Redlich-Kwong, Soave-Redlich-Kwong, Peng-Robinson, Valderrama-Cisternas, Patel-Teja, Lawal-Lake- Silberberg and Matin and Hou equation of state. After comprehensive comparisons and analysis of the values measured and calculated for a wide range of p,T conditions during carbon dioxide injection on the Ivanić oilfield, some of equations of state were recommended for determinations carbon dioxide changes of state

The cosmic-ray contribution to galactic abundances of the light elements: Interpretation of GCR LiBeB abundance measurements from ACE/CRIS

Inelastic collisions between the galactic cosmic rays (GCRs) and the interstellar medium (ISM) are responsible for producing essentially all of the light elements Li, Be, and B (LiBeB) observed in the cosmic rays. Previous calculations (e.g., [1]) have shown that GCR fragmentation can explain the bulk of the existing LiBeB abundance in the present day Galaxy. However, elemental abundances of LiBeB in old halo stars indicate inconsistencies with this explanation. We have used a simple leaky-box model to predict the cosmic-ray elemental and isotopic abundances of LiBeB in the present epoch. We conducted a survey of recent scientific literature on fragmentation cross sections and have calculated the amount of uncertainty they introduce into our model. The predicted particle intensities of this model were compared with high energy (E_(ISM) = 200–500 MeV/nucleon) cosmic-ray data from the Cosmic Ray Isotope Spectrometer (CRIS), which indicates fairly good agreement with absolute fluxes for Z ≥ 5 and relative isotopic abundances for all LiBeB species

Quantum simulation of decoherence in optical waveguide lattices

We suggest that propagation of nonclassical light in lattices of optical waveguides can provide a laboratory tool to simulate quantum decoherence phenomena with high non-Markovian features. As examples, we study decoherence of optical Schr\"{o}dinger cats in a lattice that mimics a dissipative quantum harmonic oscillator coupled to a quantum bath, showing fractional decoherence in the strong coupling regime, and Bloch oscillations of optical Schr\"{o}dinger cats, where damped revivals of the coherence can be observed.Comment: 5 pages, 2 figures (to appear in Optics Letters