28 research outputs found
Research on the application of renewable energy in power system based on adaptive hierarchical fuzzy logic maintenance
Condition-based maintenance is very desirable for minimizing the maintenance and failure costs of power systems without sacrificing reliability. A systematic approach including an adaptive maintenance advisor and a system maintenance optimizer is proposed here for effectively handling the operational variations and uncertainties for condition-based maintenance. First, the maintenance advisor receives and implements the maintenance plans for its key components from the system maintenance optimizer, which optimizes the maintenance schedules with multi-objective evolutionary algorithm, considering only major system variables and the overall system performance. During operation, the offshore substation will experience continuing ageing and shifts in control, weather and load factors, measurement and human judgment detected from the connected grid and all other equipments with uncertainties. Then, the advisor estimates the changes of reliability indices due to operational variations and uncertainties of its key components by hierarchical fuzzy logic and sends the changes back to the maintenance optimizer. The maintenance optimizer will upgrade the load-point reliability and report any drastic deterioration of reliability within each substation, which may lead to re-optimization of the substation's maintenance activities for meeting its desired reliability. The offshore substation connected to a medium-sized onshore grid will be studied here to demonstrate the ability of this proposed approach in dealing with uncertainties in the implementation of maintenance with significant reduction of computational complexity and rule base
Engineering the Structure and Properties of DNA-Nanoparticle Superstructures Using Polyvalent Counterions
DNA assembly of nanoparticles is
a powerful approach to control
their properties and prototype new materials. However, the structure
and properties of DNA-assembled nanoparticles are labile and sensitive
to interactions with counterions, which vary with processing and application
environment. Here we show that substituting polyamines in place of
elemental counterions significantly enhanced the structural rigidity
and plasmonic properties of DNA-assembled metal nanoparticles. These
effects arose from the ability of polyamines to condense DNA and cross-link
DNA-coated nanoparticles. We further used polyamine wrapped DNA nanostructures
as structural templates to seed the growth of polymer multilayers
via layer-by-layer assembly, and controlled the degree of DNA condensation,
plasmon coupling efficiency, and material responsiveness to environmental
stimuli by varying polyelectrolyte composition. These results highlight
counterion engineering as a versatile strategy to tailor the properties
of DNA-nanoparticle assemblies for various applications, and should
be applicable to other classes of DNA nanostructures