This study demonstrates a high-performance capillary electrophoresis electrochemical (CE-EC) microchip featuring embedded the palladium nanoelectrode ensemble (Pd-NEE) as the decoupler. The Pd-NEE is fabricated utilizing a new composition of electroless plating bath for depositing palladium in the porous polycarbonate thin film. Palladium has the adsorbability and permeability to hydrogen, such that the produced Pd-NEE is able to eliminate the hydrogen formation from the high separation voltage and to reduce the background current for electrochemical detection. Moreover, this study adopts the oxygen plasma to etch the nanoelectrode ensemble to enlarge the exposed surface areas to further enhance the decoupling performance of the Pd-NRE. Experimental results show that the developed Pd-NEE decoupler is capable of decoupling the electrophoretic current such that the hydrogen formation on the electrochemical electrodes was suppressed. Results indicate the developed Pd-NEE decoupler greatly enhance the S/N ratio for the electrochemical signal and lower the detectable concentration for the bio-sample of the dopamine and catechol. The detection limit of dopamine and catechol are 50 nM and 100 nM using the microchip with the Pd-NEE decoupler. Furthermore, results also indicate that the palladium nanorod ensemble (Pd-NRE) decoupler produced using the oxygen plasma etching of Pd-NEE have better electrochemical detection performance in compared with the Pd-NEE decoupler. The background current of the electrochemical detection obtained with the microchip with Pd-NRE decoupler is about 5.6 pA at applied electric field of 800 V/cm electric field. In addition, combining the gold nanorod ensemble (GNRE) as the working electrode, the detection limit is lower to 10 nM and 50 nM, respectively. This study presents a high efficiency CE-EC microchip with a Pd-NRE decoupler and a GNRE working electrode which not only decreases the background current but improves the detection limit.

A new numerical methodology to examine fluid-structure interaction of a wing/pylon/store system has been developed. The aeroelastic equation of motion of the complete system is solved iteratively in the time domain using a two-entity numerical code comprised of ABAQUS/Standard and the Unsteady-Vortex-Lattice Method. Both codes communicate through an iterative handshake procedure during which displacements and air loads are updated. For each increment in time the force/displacement equilibrium is found in this manner. The wing, pylon, and store data considered in this analysis are based on an F16 configuration that was identified to induce flutter in flight at subsonic speeds. The wing structure is modeled as an elastic plate and pylon and store are rigid bodies. The store body is connected to the pylon through an elastic joint exercising pitch and yaw degrees of freedom. Vortex-Lattice theory featuring closed ring-vortices and continuous vortex shedding to form the wakes is employed to model the aerodynamics of wing, store, and pylon. The methodology was validated against published data demonstrating excellent agreement with documented key phenomena of fluid-structure iteration. The model correctly predicts the effects of the pylon induced lateral flow disruption as well as wing-tip-vortex effects. It can identify the presence of aerodynamic interference between the store, pylon, and wing wakes and examine its significance with respect to the pressure and lift forces on the participating bodies. An elementary flutter study was undertaken to examine the dynamic characteristics of a stiff production pylon at near-critical airspeeds versus those of a soft-in-pitch pylon. The simulation reproduced the stabilizing effect of the stiffness reduction in the pitch motion. This idea is based on the concept of the decoupler pylon, introduced by Reed and Foughner in 1978 and flight tested in the early 1980's. NOTE: (3/07) An updated copy of this ETD was added after there were patron reports of problems with the file. / Ph. D.

In recent years, combat aircraft with external stores have experienced a decrease in their mission capabilities due to lack of robustness of the current passive wing/store flutter suppression system to both structured as well as unstructured uncertainties. The research program proposed here is to investigate the feasibility of using a piezoceramic wafer actuator for active control of store flutter with the goal of producing a robust feedback system that demonstrates increased performance as well as robustness to modeling errors. This approach treats the actuator as an active soft-decoupling tie between the wing and store, thus isolating the wing from store pitch inertia effects. Advanced control techniques are used to assess the nominal performance and robustness of wing/store system to flutter critical uncertainties. NOTE: (10/2009) An updated copy of this ETD was added after there were patron reports of problems with the file. / Ph. D.

Inertial stabilized platforms consisting of a two-axis gimbal assembly are often modelled as two independent SISO systems, describing the dynamics of the elevation axis and the azimuth axis respectively. In reality the state of the elevation channel and the state of the azimuth channel affect each other. Hence, the system is better modelled as a MIMO system with coupled dynamics, which means that the system has multiple inputs and outputs, where each input can affect multiple outputs. Since the couplings between the elevation channel and the azimuth channel have a deteriorating effect on control it is of interest to analyse what gives rise to the coupled dynamics and if control performance can be improved by considering the coupled dynamics. For this purpose, this thesis attempts to derive a dynamic model of the system of interest, both with the aid of physical modeling and system identification. Both modeling methods result in models with similar dynamics which seem to capture the coupled dynamics in the relevant frequency range. From the physical modeling it can be inferred that the degree of coupled dynamics depends on the mass distribution of the two-axis gimbal assembly. For the specific configuration of the system used in this investigation, the degree of coupled dynamics proved to be relatively small with relatively small impact on control. Based on the derived models, three types of controllers were implemented, decentralized control, decentralized control with a decoupler and decentralized control with an inner loop for rejection of mutual disturbances acting between the elevation axis and azimuth axis. Compared to standard decentralized control, the decoupler resulted in a somewhat better reference tracking and in a somewhat worsened disturbance rejection. Compared to standard decentralized control, the inner loop disturbance compensator resulted in a somewhat better performance for reference and disturbance rejection. / Inertialstabiliserade plattformar bestående av en tvåaxlig gimbal modelleras ofta som två oberoende SISO system som beskriver dynamiken för rörelse kring elevationsaxeln respektive azimutaxeln. I verkligheten påverkar tillstånden i elevationskanalen samt azimutkanalen varandra. Därmed kan systemet bättre modelleras som ett kopplat MIMO system, vilket innebär ett system med multipla in och utsignaler, där varje insignal kan påverka flera utsignaler. Eftersom den kopplade dynamiken har en försämrande effekt på systemets reglerprestanda är det av intresse att undersöka varför den kopplade dynamiken uppkommer, samt om reglerprestanda kan förbättras genom att beakta den kopplade dynamiken. För att undersöka detta söker denna rapport att med fysikalisk modellering samt systemidentifiering bygga en modell av systemet som innehåller den kopplade dynamiken. Båda metoderna resulterar i modeller med liknande dynamik, som verkar fånga den kopplade dynamiken i det relevanta frekvensspannet. Från den fysikaliska modelleringen kan det härledas att graden av kopplad dynamik beror på massfördelningen av systemet. För den specifika konfigurationen av systemet som var föremål för denna undersökning visar det sig att den kopplade dynamiken är relativt svag med relativt liten inverkan på reglerprestanda. Baserat på de framtagna modellerna implementerades och undersöktes tre typer av controllers, decentralized control, decentralized control med en decoupler, samt decentralized control med en inre loop för kompensering av störningar mellan elevations- och azimutaxeln. Jämfört med endast decentralized control gav decouplern något bättre reglerprestanda med avseende på reference tracking, men något sämre reglerprestanda med avseende på disturbance rejection. Jämfört med endast decentralized control gav en inre loop för kompensering av störningar mellan elevations- och azimutaxeln något bättre reglerprestanda med avseende på reference tracking samt disturbance rejection.