Wave disturbance filtering in dynamic positioning systems

Three different approaches to wave disturbance filtering in dynamic positioning systems are studied in this paper. It is shown that a conventional design based on notch filters leads to approximately the same achievable performance of the total control system as can be achieved with an observer based design. It is also shown that a proposed passivity based design leads to a conventional filter with PD-controller. However, there is a relation between the parameters in the filter and the PD-controller, which ensures the passivity properties of the control system

Silver nanoparticles‐tragacanth gel as a green membrane for effective extraction and determination of capecitabine

A novel eco-friendly and effective electromembrane extraction method combining high-performance liquid chromatography with UV detection was developed for the enrichment and determination of capecitabine. Tragacanth-silver nanoparticles conjugated gel was prepared by dissolving the tragacanth powder in synthesized silver nanoparticles solution and was used as a green membrane in electromembrane extraction. The porosity and presence of silver nanoparticles in the gel were characterized by field emission scanning electron microscopy. This new electromembrane extraction approach uses neither organic solvent nor carrier agents to extract the target analyte. The best electromembrane extraction efficiency was obtained by using 4.0 mm membrane gel thickness containing 2.5% w/v of tragacanth gum, donor phase pH = 5.0, acceptor phase pH = 3.0, applied voltage 50 V, extraction time 20 min, and agitation rate 500 rpm. During method validation under the optimized conditions, good linearity dynamic range between 1 and 500 ng/mL with the coefficient of determination (R-2) = 0.998 was obtained. Limit of detection and Limit of quantitation were estimated to be 0.84 and 1.0 ng/mL, respectively. Finally, the applicability of this method in real samples was confirmed by an acceptable performance in extraction and determination of capecitabine in human plasma samples