Quantification of condition monitoring benefit for offshore wind turbines

Condition monitoring (CM) systems are increasingly installed in wind turbines with the goal of providing component-specific information to wind farm operators, theoretically increasing equipment availability via maintenance and operating actions based on this information. In the offshore case, economic benefits of CM systems are often assumed to be substantial, as compared with experience of onshore systems. Quantifying this economic benefit is non-trivial, especially considering the general lack of utility experience with large offshore wind farms. A quantitative measure of these benefits is therefore of value to utilities and operations and maintenance (O & M) groups involved in planning and operating future offshore wind farms. The probabilistic models presented in this paper employ a variety of methods including discrete-time Markov Chains, Monte Carlo methods and time series modelling. The flexibility and insight provided by this framework captures the necessary operational nuances of this complex problem, thus enabling evaluation of wind turbine CM offshore. The paper concludes with a study of baseline CM benefit, sensitivity to O & M costs and finally effectiveness of the CM system itself

Modifying the red cell surface: towards an ABO-universal blood supply

Eliminating the risk for ABO-incompatible transfusion errors and simplifying logistics by creating a universal blood inventory is a challenging idea. Goldstein and co-workers pioneered the field of enzymatic conversion of blood group A and B red blood cells (RBCs) to O (ECO). Using alpha-galactosidase from coffee beans to produce B-ECO RBCs, proof of principle for this revolutionary concept was achieved in clinical trials. However, because this enzyme has poor kinetic properties and low pH optimum the process was not economically viable. Conversion of group A RBCs was only achieved with the weak A(2) subgroup with related enzymes having acidic pH optima. More recently, the identification of entirely new families of bacterial exoglycosidases with remarkably improved kinetic properties for cleaving A and B antigens has reinvigorated the field. Enzymatic conversion of groups A, B and AB RBCs with these novel enzymes resulting in ECO RBCs typing as O can now be achieved with low enzyme protein consumption, short incubation times and at neutral pH. Presently, clinical trials evaluating safety and efficacy of ECO RBCs are ongoing. Here, we review the status of the ECO technology, its impact and potential for introduction into clinical component preparation laboratories