8 research outputs found
Revealing inflow and wake conditions of a 6 MW floating turbine
We investigate the characteristics of the inflow and the wake of a 6 MW floating wind turbine from the Hywind Scotland offshore wind farm, the world's first floating wind farm. We use two commercial nacelle-mounted lidars to measure the up- and downwind conditions with a fixed and a scanning measuring geometry, respectively. In the analysis, the effect of the pitch and roll angles of the nacelle on the lidar measuring location is taken into account. The upwind conditions are parameterized in terms of the mean horizontal wind vector at hub height, the shear and veer of the wind profile along the upper part of the rotor, and the induction of the wind turbine rotor. The wake characteristics are studied in two narrow wind speed intervals between 8.5–9.5 and 12.5–13.5 m s−1, corresponding to below and above rotor rated speeds, respectively, and for turbulence intensity values between 3.3 %–6.4 %. The wake flow is measured along a horizontal plane by a wind lidar scanning in a plan position indicator mode, which reaches 10 D downwind. This study focuses on the downstream area between 3 and 8 D. In this region, our observations show that the transverse profile of the wake can be adequately described by a self-similar wind speed deficit that follows a Gaussian distribution. We find that even small variations (∼1 %–2 %) in the ambient turbulence intensity can result in an up to 10 % faster wake recovery. Furthermore, we do not observe any additional spread of the wake due to the motion of the floating wind turbine examined in this study.</p
Simulation of porosity field using wavelet Bayesian inversion of crosswell GPR and log data
Multiple scale porosity simulation using wavelet decomposition of GPR tomographies and hydrogeophysical analogues
Stochastic Borehole Radar Velocity and Attenuation Tomographies Using Cokriging and Cosimulation
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The effect of intake on protein metabolism across splanchnic tissues in growing beef steers
The contribution of the total splanchnic tissue (TSP; portal-drained viscera (PDV) plus liver) to whole-body protein metabolism was estimated in relation to intake (0×6, 1×0 and 1×6 maintenance requirements), in six multicatheterized growing beef steers used in a double 3x3 Latin square design. At the end of each 21 d experimental period, [1-13C]leucine was infused into a jugular vein (1×05 mmol/h for 5 h, preceded by a priming dose of 1×05 mmol). Arterial, portal and hepatic blood samples were collected hourly during the infusion. The increment in TSP leucine irreversible loss rate (ILR) observed with increasing intake reached significance (P,0×10) only for PDV, while whole-body ILR increased markedly (P,0×001) with intake. The relative contribution of TSP to whole-body leucine ILR averaged 44% (25% from PDV and 19% from the liver). Although these proportions were not affected by intake, on an incremental basis more than 70% of the increase of whole-body leucine ILR between the 0×6 and 1×0 X maintenance originated from the changes in TSP ILR, while the corresponding value was below 13% between 1×0 and 1×6 ´ maintenance. Total whole-body leucine oxidation and fractional oxidation increased (P,0×05) with intake. Protein retention increased with intake (P,0×01), as a result of a greater increase in protein synthesis compared with protein degradation. Protein breakdown had a major impact on protein turnover as 65% of the protein synthesized was degraded when intake varied from 1×0 to 1×6 x maintenance. Net leucine portal absorption increased (P,0×001) with intake and represented 1, 16 and 23% of whole body leucine ILR, for 0×6, 1×0 and 1×6 ´ maintenance, respectively. Although leucine oxidation was not a major component of whole body ILR (9×3–19×9 %), it represented 69% of the net available leucine (portal absorption) even at 1×6 ´ maintenance. The lower relative contribution of the TSP to whole-body leucine ILR at higher intake indicates the proportional increase in the metabolic activity of peripheral tissues as the animals moved into positive protein balance