Iron (Fe) is an important limiting nutrient that can affect the rate of ocean primary production because it is required by phytoplankton as an enzymatic cofactor in photosynthesis, nitrogen fixation, and other essential metabolic functions. Most Fe reaches the surface of the open ocean via atmospheric dust deposition, which is...
One of the principal drivers of climate change is the concentration of greenhouse gases such as CO2 in the atmosphere. A large portion of this CO2 ends up in the waters off the continental coasts where it transforms into biomass. The major sink for this matter is the ocean sediments...
Copper and iron are essential micronutrients that are required by marine primary producers for a variety of metabolic processes. Over 99% of both copper and iron are bound within organic complexes in the marine environment, however the molecular identity of many of these complexes remains unknown. The speciation of these...
Environmental archives provide records of natural and anthropogenic variation in the environment at different temporal and spatial scales. Lead (Pb) concentrations and isotopic ratios are useful tracers of anthropogenic emissions from industrial activities including mining, smelting, and leaded gasoline use, however, methods of measuring Pb are largely limited in low...
This thesis presents the development of dynamic control strategies for the
brushless doubly-fed machine (BDFM). A simple open-loop scalar controller is first
investigated and its response is found to be oscillatory. Using the speed feedback
signal, an improved closed loop scalar control algorithm is designed. Steady state
performance is controlled...
A sucrose density-gradient ultracentrifugation technique for
obtaining microsomes has been developed. This technique has
advantages over the classic differential centrifugation technique, in
that it is faster, is better suited to work with small quantities of
tissue, and offers the opportunity to work with a defined microsomal
sub-cellular fraction, rather than...
In the cockroach Leucophaea maderae, a centre in the brain controls the female's acceptance of courting males. This centre is affected by starvation. A brief exposure to food can induce mating but is inadequate for oocyte development. In fed L. maderae there appears to be a synergistic action of nutrition...
An AC/AC converter has been designed and implemented for the purpose of
providing a modular drive system with a Brushless Doubly-Fed Machine (BDFM.) This
converter is to be used in laboratory testing and also as part of a demonstration system in
the field.
All hardware needed to start and run...
The Brushless Doubly-Fed Machine (BDFM) has recently become an
important research topic in the field of variable-speed AC drives. In
recent studies, the BDFM has shown significant potential for improving the
reliability and performance of AC drive systems, as well as reducing total
system cost. While the BDFM offers several...
The alternators in today's automobiles are of the claw-pole or Lundell
construction, which is a readily manufactured, low-cost derivative of the conventional
rotating dc field synchronous generator. The efficiency of the Lundell system is low due
to a complicated magnetic circuit of predominantly solid steel and a high windage rotor...