Browsing by Author "Sequeira, C."
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- Application of simple harmonic motion theory to the prediction of floating wind turbine first order motionsPublication . Mackie, G.; Pacheco, André; Sequeira, C.An alternative solution for achieving a high stability floating foundation for supporting large horizontal axis wind turbines is compared against current floating offshore wind solutions. The testing of a 1:36th scale model of the solution, called Starfloat, in the wind/wave basin of the Cantabria Coastal and Ocean Basin, Santander and the design of this physical model, including scaling issues, is discussed. A method for calculating the added mass of entrained water in heave and surge and the added mass moment of inertia in pitch for semi-submerged cy-lindrical columns is presented and the computed natural periods of motion are compared against physical trial measurements obtained from motion decay tests. The wave forces exciting the simple harmonic motion are calculated and the resultant approximate solution for the uncoupled floating platform motions in heave, pitch and surge are compared against response amplitude operator curves obtained from the physical model trials, showing reasonable correlation. The importance of depth correction for wave particle velocities and accelera-tions is very evident and emphasises the need for physical models to be exposed to the correct orbital particle motions over the water column if measured pitch and surge motions are to be a realistic representation of full scale performance.
- Large scale evaluation of primers for diagnosis of rupestris stem pitting associated virus-1Publication . Nolasco, Gustavo; Mansinho, A.; Santos, M. T.; Soares, C.; Sequeira, Z.; Sequeira, C.; Correia, P. K.; Sequeira, O. A.The unavailability of adequate immunological reagents has prevented the use of ELISA for the diagnosis of rupestris stem pitting disorder of grapevines. In this work, the performance of five primer pairs for broad-scale detection of rupestris stem pitting associated virus-1 by RT-PCR using ds-RNA templates was compared and contrasted with biological indexing. The virus was widespread among the budwood of 35 Portuguese grapevine varieties assayed, with a prevalence of 85%. The biological assay proved to be unreliable as an index of infection due to the high number of false negatives. Five sets of primers were assayed and compared by means of their relative sensitivity and negative predictive value. The primer pair specific for the coat protein gene was excluded because of the difficulty in identifying the specific amplified product. From the other four primer pairs, those specific for the helicase domain of the putative polymerase gene had the highest sensitivity and negative predictive value. However, a high confidence in the assay, as desirable for a certification scheme, could not be obtained by the sole use of this primer pair. An additional pair should be used in a separate or in a multiplex RT-PCR reaction.