Evaluation of the global-blockage effect on power performance through simulations and measurements

Blockage effects due to the interaction of five wind turbines in a row are investigated through both Reynolds-averaged Navier-Stokes simulations and site measurements. Since power performance tests are often carried out at sites consisting of several turbines in a row, the objective of this study is to evaluate whether the power performance of the five turbines differs from that of an isolated turbine. A number of simulations are performed, in which we vary the turbine inter-spacing (1.8, 2 and 3 rotor diameters) and the inflow angle between the incoming wind and the orthogonal line to the row (from 0° to 45°). Different values of the free-stream velocity are considered to cover a broad wind speed range of the power curve. Numerical results show consistent power deviations for all the five turbines when compared to the isolated case. The amplitude of these deviations depends on the location of the turbine within the row, the inflow angle, the inter-spacing and the power curve region of operation. We show that the power variations do not cancel out when averaging over a large inflow sector (from −45° to +45°) and find an increase in the power output of up to +1 % when compared to the isolated case. We simulate power performance ‘measurements’ with both a virtual mast and nacelle-mounted lidar and find a combination of power output increase and upstream velocity reduction, which causes an increase of +4 % of the power coefficient. We also use measurements from a real site consisting of a row of five wind turbines to validate the numerical results. From the analysis of the measurements, we also show that the power performance is impacted by the neighboring turbines. Compared to when the inflow is perpendicular to the row, the power output varies of +1.8 % and −1.8 % when the turbine is the most downwind and upwind of the line, respectively.

EXPTIME Hardness of an n by n Custodian Capture Game

Custodian capture occurs when a player has placed two of his pieces on the opposite sides of an orthogonal line of the opponent’s men. Each piece moves like the rook in Chess. Different cultures played it from pre-modern times in two-player strategy board games, Ludus Latrunculorum (Kowalski’s reconstruction), Hasami shogi in Japan, Mak-yek in Thailand and Myanmar, Ming Mang in Tibet, and so on. We prove that a custodian capture game on n×n square board is EXPTIME hard if the first player to capture five or more men in total wins.

Selective Activity-Based Probes Targeting Fibroblast Activation Protein (FAP)

Fibroblast activation protein (FAP) is a type II transmembrane serine protease that belongs to the dipeptidyl peptidase (DPP) family. Although FAP expression is practically non-existent in the majority of healthy adult tissues, it is clearly upregulated in tissue remodeling processes associated with several diseases. These include cancer, atherosclerosis, arthritis, hepatic, and pulmonary fibrosis. This finding has recently sparked intensive research aiming at the clinical implementation of FAP as a diagnostic and/or prognostic biomarker for the aforementioned diseases. Several immunochemical approaches have been reported that can quantify FAP expression. The main drawback of these approaches, however, lies in the fact that some of the commercially available FAP antibodies have been reported to lack specificity. On the other hand, an orthogonal line of research focuses on the quantification of the enzymatically active fraction of FAP, generally relying on peptidic activity-based probes. Developing a selective activity-based assay for FAP has proven to be challenging, owing to the frequently encountered lack of probe selectivity towards prolyl oligopeptidase (PREP, PO). In response, we report a novel series of activity-based FAP probes, based on our potent and selective inhibitor UAMC-1110.

Generalized transformations and coordinates for static spherically symmetric general relativity

We examine a static, spherically symmetric solution of the empty space field equations of general relativity with a non-orthogonal line element which gives rise to an opportunity that does not occur in the standard derivations of the Schwarzschild solution. In these derivations, convenient coordinate transformations and dynamical assumptions inevitably lead to the Schwarzschild solution. By relaxing these conditions, a new solution possibility arises and the resulting formalism embraces the Schwarzschild solution as a special case. The new solution avoids the coordinate singularity associated with the Schwarzschild solution and is achieved by obtaining a more suitable coordinate chart. The solution embodies two arbitrary constants, one of which can be identified as the Newtonian gravitational potential using the weak field limit. The additional arbitrary constant gives rise to a situation that allows for generalizations of the Eddington–Finkelstein transformation and the Kruskal–Szekeres coordinates.