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Groundwater contains dissolved He, and its concentration increases with the residence time of the groundwater. Thus, if the 4He accumulation rate is constant, the dissolved 4He concentration in ground-water is equivalent to the residence time. Since accumulation mechanisms are not easily separated in the field, we estimate the total He accumulation rate during the half-life of 36Cl (3.01 × 105 years). We estimated the 4He accumulation rate, calibrated using both cosmogenic and subsurface-produced 36Cl, in the Great Artesian Basin (GAB), Australia, and the subsurface-produced 36Cl increase at the Äspö Hard Rock Laboratory, Sweden. 4He accumulation rates range from (1.9±0.3) × 10−11 to (15±6) × 10−11 ccSTP·cm−3·y−1 in GAB and (1.8 ±0.7) × 10−8 ccSTP·cm−3·y−1 at Äspö. We confirmed a ground-water flow with a residence time of 0.7-1.06 Ma in GAB and stagnant groundwater with the long residence time of 4.5 Ma at Äspö. Therefore, the groundwater residence time can be deduced from the dissolved 4He concentration and the 4He accumulation rate calibrated by 36Cl, provided that 4He accumulation, groundwater flow, and other geo-environmental conditions have remained unchanged for the required amount of geological time.

The kinetics of the photodarkening effect is analyzed for amorphous selenium (s-Se) layers at room temperature and at an elevated temperature close to the glass transition. The energy barrier responsible for the relaxation of the reversible component at room temperature is the same as at 35 degree Celsius, indicating that the energy barrier has represented a fundamental feature of the photoinduced structural metastability in amorphous selenium.

We investigate the rearrangement of the director in thin films of nematic liquid crystals caused by tightly focusing circularly polarized laser beams. We find either target or spiral patterns, depending on the topology of the director configuration at the position of the beam focus. The induced rearrangements of the director are governed by the viscosity of the media, the handedness of circular polarization, and the irradiation power of the laser. Experimental observations are interpreted using a model derived from nematic continuum theory. [ABSTRACT FROM AUTHOR]

An in-beam gamma-ray spectroscopy study, following a fusion reaction induced by a neutron-rich secondary beam, 46Ar + 9Be, is presented. A low-energy secondary beam of 46Ar at ∼ 5 MeV/ A was developed in order to induce fusion reactions. Gamma-gamma coincidence and excitation function analysis was performed to study high-spin states in the vicinity of 48Ca, 49-52Ti . [ABSTRACT FROM AUTHOR]

We estimated the groundwater age from 228Ra/226Ra ratios in young groundwater and relevant rocks in the volcanic area of the Kakitagawa River around Mount Fuji, Japan, and compared our results with those from 3H/3He age determination. The groundwater residence time estimated from the 228Ra/226Ra activity ratio in groundwater and relevant rocks agreed well with the 3H/3He age, suggesting that the 228Ra/226Ra ratio of groundwater can be used to estimate residence time of young groundwater in volcanic areas.