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226Ra, 238U, 4 K, and 232Th (228Ra) activity concentrations of 61 soil samples distributed surrounding the rare earth element mine (NORM), MH, Lao Cai, Vietnam have been measured by HPGe detector. The activity concentrations of 226Ra, 238U, 4 K, and 232Th (228Ra) range from 1179 to 6291 Bq/kg, from 1024 to 8351 Bq/kg, from 260 to 3519 Bq/kg, and from 1476 to 35546 Bq/kg in the ore body and from 21.3 to 964 Bq/kg, from 23.4 to 1635 Bq/kg, from 124 to 3788 Bq/kg, and from 40.9 to 6107 Bq/kg outside the ore body in respective. The study area is considered as the high local natural background radiation with the concentration of 226Ra, 238U, 4 K, and 232Th (228Ra) of 156, 254, 647, and 908 Bq/kg in respective. Regarding the spatial distribution, the measured radionuclide concentrations are independent of the distance from measured points to the ore body. With regard to the hazard indices, the average calculated radiological hazard indices, including absorbed gamma dose rate, effective dose equivalent, and excess lifetime cancer risk significantly exceed the global average values. There is a disequilibrium between 238U/226Ra concentrations in studied soil samples. The results also found that the 232Th (228Ra) concentration and total absorbed gamma dose rate show a strong positive correlation (coefficient of determination, R2 = 1).

A numerical model was developed of beach morphological evolution in the vicinity of coastal structures. The model includes five sub-models for random wave transformation, surface roller development, nearshore wave-induced currents, sediment transport, and morphological evolution. The model was validated using high-quality data sets obtained during experiments with a T-head groin and a detached breakwater in the basin of the Large-scale Sediment Transport Facility at the Coastal and Hydraulics Laboratory in Vicksburg, Miss, USA. The simulations showed that the model reproduced well the wave conditions, wave-induced currents, and beach morphological evolution in the vicinity of coastal structures. Both salient and tombolo formation behind a T-head groin and a detached breakwater were simulated with good agreement compared to the measurements. (C) 2011 Elsevier B.V. All rights reserved.

A new numerical model was developed to simulate regional sediment transport and shoreline response in the vicinity of tidal inlets based on the one-line theory combined with the reservoir analogy approach for volumetric evolution of inlet shoals. Sand bypassing onshore and sheltering effects on wave action from the inlet bar and shoals were taken into account. The model was applied to unique field data from the south coast of Long Island, United States, including inlet opening and closure. The simulation area extended from Montauk Point to Fire Island Inlet, including Shinnecock and Moriches Inlets. A 20-year long time series of hindcast wave data at three stations along the coast were used as input data to the model. The capacity of the inlet shoals and bars to store sand was estimated based on measured cross-sectional areas of the inlets as well as on comprehensive bathymetric surveys of the areas around the inlet. Several types of sediment sources and sinks were represented, including beach fills, groin systems, jetty blocking, inlet bypassing, and flood shoal and ebb shoal feeding. The model simulations were validated against annual net longshore transport rates reported in the literature, measured shorelines, and recorded sediment volumes in the flood and ebb shoal complexes. Overall, the model simulations were in good agreement with the measured data.