[en] Cosmogenic noble gas isotope 21Ne in terrestrial rocks has been used primarily to determine timing and rates of the Earth’s surface evolution. Here we explore the ability of detrital 21Ne as a provenance tracer, considering that Ne isotopes produced in source rocks could be preserved in minerals over geological time and might be predominant in total Ne inventory of sediments sunk in basins. This ability is predicated on potential source terranes of a given stratigraphic section with distinct neon isotopic signatures. Here we analyze neon isotopes of a well-dated Miocene–Pleistocene sedimentary archives in Kuqa foreland basin of southern Tianshan. The data suggest that the neon isotopic signature, which is expressed as εNe and defined in this work as the excess 21Ne/20Ne-ratio relative to atmospheric ratio, is stratigraphically sensitive to changes in local source terranes. This result is compatible with U/Pb provenance analysis and also supported by evidences from sandstone petrography and heavy mineral analysis. Influence of other non-source related 21Ne components in sedimentary archives on sensitivity of εNe has proven to be negligible. Furthermore, the integrated stratigraphic signatures of neon isotope and U/Pb age permit the detection of differential erosion in drainage basin, by which the tectonic or climatic effects on geomorphic evolution could be deciphered.

[en] Materials of choice for offshore structures and the marine industry have been increasingly favoring materials that offer high strength-to-weight ratios. One of the most promising families of light-weight materials is titanium alloys, but these do have two potential Achilles' heels: (i) the passive film may not form or may be unstable in low oxygen environments, leading to rapid corrosion; and (ii) titanium is a strong hydride former, making it vulnerable to hydrogen embrittlement (cracking) at high temperatures in low oxygen environments. Unfortunately, such environments exist at deep sea well-heads; temperatures can exceed 120 °C, and oxygen levels can drop below 1 ppm. The present study demonstrates the results of investigations into the corrosion behavior of a range of titanium alloys, including newly developed alloys containing rare earth additions for refined microstructure and added strength, in artificial seawater over the temperature range of 25 °C to 200 °C. Tests include potentiodynamic polarization, crevice corrosion, and U-bend stress corrosion cracking

No abstract available

[en] Doses due to stray radiation produced by high energy electrons are calculated for the shielding materials lead, iron, heavy and ordinary concrete, and sand. Source terms and absorption coefficients were determined using the Monte Carlo program EGS4 for 12 different target configurations, for primary energies between 0.15 and 50 GeV, and for the target materials iron and aluminium. The dependencies on the primary energy, target configurations, and angle of observation were studied. The results are compared with experimental values at 5 GeV; the agreement is good. The results are parameterised to facilitate dose calculations. (author)

[en] Doses due to electrons and photons behind beam absorbers are calculated for beam energies between 0.15 and 50 GeV using the Monte Carlo program EGS4. Absorber materials are sand, ordinary concrete, heavy concrete, copper and lead. At 6 GeV the results are compared with experimental values. From all results a simple formula is deduced to facilitate dose calculations. (author)

[en] This paper studies the output properties of GeV electron bunches driven by ultra-intense lasers in vacuum based on the mechanism of capture and violent acceleration scenario [CAS, see e.g. J.X. Wang, et al., Phys. Rev. E 58 (1998) 6575]. We find that the output of the acceleration mechanism is a GeV electron macro-pulse which consists of many micro-pulses corresponding to the periodicity of the laser wave. The outgoing electrons can generally be divided into two groups. One spreads greatly in space and the other is a high-energy bunch with limited spread in space. Provided that the incoming electron bunch with comparable sizes as that of the laser pulse synchronously impinges on the laser pulse, the total fraction of CAS electrons can reach more than 20% of the incident electrons. These results demonstrate that the CAS is a pretty effective accelerator mechanism

[en] By taking account of the high-order corrections to the paraxial approximation of a Gaussian beam, it has been verified that for a focused laser beam propagating in vacuum, there indeed exists a subluminous wave phase velocity region surrounding the laser beam axis. The magnitude of the phase velocity scales as V_φm∼c(1+b/(kw₀)²), where V_φm is the phase velocity of the wave, c is the speed of light in vacuum, w₀ is the beam width at focus. This feature gives a reasonable explanation for the mechanism of capture and acceleration scenario

No abstract available

[en] The use of high hydrogen levels in the primary circuit of a pressurized water reactor (PWR) is believed to be a possible cause of cracking of Alloy 600 steam generator tubes and other components fabricated from a variety of stainless steels and nickel-base alloys. Cracking occurs due to the electrochemical potential (ECP) being in the region for hydrogen-induced cracking, or in a region for stress corrosion cracking. In order to estimate the corrosion potential of these alloys in PWR primary environments, a series of algorithms has been developed. These algorithms have been used to determine the pH of aqueous LiOH + B(OH)₃ solutions, to calculate the concentration of radiolysis products produced in the core due to the neutron and γ-photon fluxes, and to estimate the ECP under simulated operating conditions. From these calculations, the ECP for various hydrogen concentrations, lithium to boron ratios (as specified by a given pH), and dose rates were evaluated. The authors show that under the prescribed operating conditions for PWRs ([H₂] = 25--50 cc/kg), the corrosion potential is more negative than the critical potential (-0.8 V_SHE) for the onset of hydrogen induced intergranular cracking in Alloy 600. However, by lowering the hydrogen concentration to less than 4 cc/kg at a pH of 7.5 and to less than 10 cc/kg at a pH of 7.0, the authors predict that it would be possible to protect Alloy 600 from fracture

[en] This preliminary report was undertaken in order to determine at a high level the range of nuclear power workers, electricity generation capacity, and plant technologies to be considered in future more detailed plant specific workforce and cost benefit analysis scenarios for Australia by 2050. Previous studies of nuclear power deployment in Australia took into consideration the economic and environmental benefits. An Australian governmentcommissioned report (UMPNER, 2006) revealed the economic and environmental costs and benefits of alternative scenarios for developing nuclear power capacity in Australia. To this date there has been no attempt to estimate the associated workforce requirements under these scenarios. This paper reports preliminary estimates of the workforce requirements, direct and indirect employment opportunities, education and skilling challenges under alternative nuclear power scenarios. Combining data from the UMPNER report generation capacity scenarios with data on occupation-specific workforce requirements from IAEA workforce averages of existing nuclear power industries, estimates are made on Australia’s nuclear workforce requirements under a number of assumed generation capacity scenarios. These estimates are provided on a sufficiently disaggregated basis to allow the identification of the specific direct and indirect skill requirements over the period 2020 to 2050. These estimates provide Australian policy makers with the basis for designing a training and workforce planning program that would be required in the event of nuclear power becoming part of Australia’s low-emission energy mix. While the workforce estimates in this report attempt to allow for a sufficient number of occupation requirements to be anticipated, industry representatives noted that ongoing consideration of the impacts of an ageing nuclear power workforce was crucial in order to avoid the potential skill shortages that are currently threatening nations with mature nuclear power industries. (author).