Acoustical evaluation of the NASA Langley full-scale wind tunnel

Determining types of acoustical measurements suitable for test section of NASA Langley wind tunne

Abundance, behavior, and movement patterns of western gray whales in relation to a 3-D seismic survey, Northeast Sakhalin Island, Russia

A geophysical seismic survey was conducted in the summer of 2001 off the northeastern coast of Sakhalin Island, Russia. The area of seismic exploration was immediately adjacent to the Piltun feeding grounds of the endangered western gray whale (Eschrichtius robustus). This study investigates relative abundance, behavior, and movement patterns of gray whales in relation to occurrence and proximity to the seismic survey by employing scan sampling, focal follow, and theodolite tracking methodologies. These data were analyzed in relation to temporal, environmental, and seismic related variables to evaluate potential disturbance reactions of gray whales to the seismic survey. The relative numbers of whales and pods recorded from five shore-based stations were not significantly different during periods when seismic surveys were occurring compared to periods when no seismic surveys were occurring and to the post-seismic period. Univariate analyses indicated no significant statistical correlation between seismic survey variables and any of the eleven movement and behavior variables. Multiple regression analyses indicated that, after accounting for temporal and environmental variables, 6 of 11 movement and behavior variables (linearity, acceleration, mean direction, blows per surfacing, and surface-dive blow rate) were not significantly associated with seismic survey variables, and 5 of 11 variables (leg speed, reorientation rate, distance-from-shore, blow interval, and dive time) were significantly associated with seismic survey variables. In summary, after accounting for environmental variables, no correlation was found between seismic survey variables and the linearity of whale movements, changes in whale swimming speed between theodolite fixes, mean direction of whale movement, mean number of whale exhalations per minute at the surface, mean time at the surface, and mean number of exhalations per minute during a whales surface-to-dive cycle. In contrast, at higher received sound energy exposure levels, whales traveled faster, changed directions of movement less, were recorded further from shore, and stayed under water longer between respirations

A western gray whale mitigation and monitoring program for a 3-D seismic survey, Sakhalin Island, Russia

The introduction of anthropogenic sounds into the marine environment can impact some marine mammals. Impacts can be greatly reduced if appropriate mitigation measures and monitoring are implemented. This paper concerns such measures undertaken by Exxon Neftegas Limited, as operator of the Sakhalin-1 Consortium, during the Odoptu 3-D seismic survey conducted during 17 August’ September 2001. The key environmental issue was protection of the critically endangered western gray whale (Eschrichtius robustus), which feeds in summer and fall primarily in the Piltun feeding area off northeast Sakhalin Island. Existing mitigation and monitoring practices for seismic surveys in other jurisdictions were evaluated to identify best practices for reducing impacts on feeding activity by western gray whales. Two buffer zones were established to protect whales from physical injury or undue disturbance during feeding. A 1 km buffer protected all whales from exposure to levels of sound energy potentially capable of producing physical injury. A 4’ km buffer was established to avoid displacing western gray whales from feeding areas. Trained Marine Mammal Observers (MMOs) on the seismic ship Nordic Explorer had the authority to shut down the air guns if whales were sighted within these buffers

Challenges for the closure and natural rehabilitation of bauxite residue disposal sites

In the Bayer process, bauxite ore is digested with NaOH at high temperature and pressure, which results in the production of alumina and the recrystallisation of various residual minerals ending up in a bauxite residue. The main minerals in this residue, which is commonly referred to as ‘red mud’, are iron and aluminium oxides (goethite, hematite, gibbsite and boehmite), Na- and Ca-aluminosilicate phases (e.g. sodalite and cancrinite) and titanium oxide. The main challenges facing the natural rehabilitation (direct revegetation) of bauxite residues are related to inherent physicochemical properties of the bauxite residue, in particular alkalinity, salinity, sodicity and low hydraulic conductivity. Physical restrictions to growth of vegetation in bauxite residue material include low hydraulic conductivity (low transport of water), poor drainage (water logging) and restricted root growth. Additionally, in dry periods, capillary rise of water and dissolved salts can occur, salts may accumulate at the cap surface, and drying cracks will occur. Pilot studies have been initiated to compare different closure solutions that take into consideration the physical, chemical and biological limitations of bauxite residues. Methods include the use of different liners, geomembranes, drainage systems and topsoil covers. Gypsum amendment and the addition of organic matter are studied as potential natural rehabilitation methods that can limit the use of pristine soil in the construction of the top cover. The study is part of the Norwegian Geotechnical Institute’s research program on sustainable mine tailings, which comprises studies on material properties, modelling and prediction of physical and chemical stability, remote sensing for long-term monitoring and risk-informed decision-making.publishedVersio

Challenges for the closure and natural rehabilitation of bauxite residue disposal sites

In the Bayer process, bauxite ore is digested with NaOH at high temperature and pressure, which results in the production of alumina and the recrystallisation of various residual minerals ending up in a bauxite residue. The main minerals in this residue, which is commonly referred to as ‘red mud’, are iron and aluminium oxides (goethite, hematite, gibbsite and boehmite), Na- and Ca-aluminosilicate phases (e.g. sodalite and cancrinite) and titanium oxide. The main challenges facing the natural rehabilitation (direct revegetation) of bauxite residues are related to inherent physicochemical properties of the bauxite residue, in particular alkalinity, salinity, sodicity and low hydraulic conductivity. Physical restrictions to growth of vegetation in bauxite residue material include low hydraulic conductivity (low transport of water), poor drainage (water logging) and restricted root growth. Additionally, in dry periods, capillary rise of water and dissolved salts can occur, salts may accumulate at the cap surface, and drying cracks will occur. Pilot studies have been initiated to compare different closure solutions that take into consideration the physical, chemical and biological limitations of bauxite residues. Methods include the use of different liners, geomembranes, drainage systems and topsoil covers. Gypsum amendment and the addition of organic matter are studied as potential natural rehabilitation methods that can limit the use of pristine soil in the construction of the top cover. The study is part of the Norwegian Geotechnical Institute’s research program on sustainable mine tailings, which comprises studies on material properties, modelling and prediction of physical and chemical stability, remote sensing for long-term monitoring and risk-informed decision-making