Publications

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

The United States produces only about 1/3 of the more than 20 million barrels of petroleum that it consumes daily. Oil imports into the country are roughly equivalent to the amount consumed in the transportation sector. Hence the nation in general, and the transportation sector in particular, is vulnerable to supply disruptions and price shocks. The situation is anticipated to worsen as the competition for limited global supplies increases and oil-rich nations become increasingly willing to manipulate the markets for this resource as a means to achieve political ends. The goal of this project was the development and improvement of technologies and the knowledge base necessary to produce and qualify a universal fuel from diverse feedstocks readily available in North America and elsewhere (e.g. petroleum, natural gas, coal, biomass) as a prudent and positive step towards mitigating this vulnerability. Three major focus areas, feedstock transformation, fuel formulation, and fuel characterization, were identified and each was addressed. The specific activities summarized herein were identified in consultation with industry to set the stage for collaboration. Two activities were undertaken in the area of feedstock transformation. The first activity focused on understanding the chemistry and operation of autothermal reforming, with an emphasis on understanding, and therefore preventing, soot formation. The second activity was focused on improving the economics of oxygen production, particularly for smaller operations, by integrating membrane separations with pressure swing adsorption. In the fuel formulation area, the chemistry of converting small molecules readily produced from syngas directly to fuels was examined. Consistent with the advice from industry, this activity avoided working on improving known approaches, giving it an exploratory flavor. Finally, the fuel characterization task focused on providing a direct and quantifiable comparison of diesel fuel and JP-8.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

This paper introduces and develops the concept of "Type X" and "Type Y" errors in model validation and calibration, and their implications on extrapolative prediction. Type X error is non-detection of model bias because it is effectively hidden by the uncertainty in the experiments. Possible deleterious effects of Type X error can be avoided by mapping uncertainty into the model until it envelopes the potential model bias, but this likely assigns a larger uncertainty than is needed to account for the actual bias (Type Y error). A philosophy of Best Estimate + Uncertainty modeling and prediction is probably best supported by taking the conservative choice of guarding against Type X error while accepting the downside of incurring Type Y error. An associated methodology involving data-and model-conditioning is presented and tested on a simple but rich test problem. The methodology is shown to appropriately contend with model bias under conditions of systematic experimental input uncertainty in the test problem. The methodology effectively bounds the uncertain model bias and brings a correction into the model that extrapolates very well under a large variety of extrapolation conditions. The methodology has been straightforwardly applied to considerably more complex real problems where system response is likewise jointly monotonic in the input uncertainties. The methodology also allows for other types of systematic and random uncertainty in the experiments and model as discussed herein. Copyright © 2008 SAE International.

We demonstrate the first high-speed second-order silicon microdisk bandpass switch. The switch, constructed of a pair of 3μm radii active microdisks possesses ~40GHz flat-top passbands, a 4.2THz free-spectral-range, and a 2.4ns switching time. © 2008 Optical Society of America.

Abstract not provided.

Predicting and controlling the evolution of materials microstructure is one of the central challenges of materials science. The simulation of microstructural evolution requires a detailed knowledge of the properties, including energies and mobilities, of interfaces in the material. We present the results of molecular dynamics simulations of these interfacial properties for a large set of boundaries.

Abstract not provided.

This paper reports post-CMOS compatible aluminum nitride dual mode resonator filters that realize 4th order band-pass filters in a single resonator device. Dual mode filters at 106 MHz operating in their fundamental mode are reported with insertion losses as low as 5.5 dB when terminated with 150 Ω. A notching technique is demonstrated for varying the 3 dB bandwidth of these filters from 0.15 to 0.7%, overcoming a significant limitation of previous work. Dual mode filters operating at their 5th and 10th overtones are reported scaling the operating frequencies of this class of device to 0.55 and 1.1 GHz.

Electrothermal actuation has been used in microelectromechanical systems where low actuation voltage and high contact force are required. Power consumption to operate electrothermal actuators has typically been higher than with electrostatic actuation. A method of designing and processing electrothermal actuators is presented that leads to an order of magnitude reduction in required power while maintaining the low voltage, high force advantages. The substrate was removed beneath the actuator beams, thereby discarding the predominant power loss mechanism and reducing the required actuation power by an order of magnitude. Measured data and theoretical results from electrothermally actuated switches are presented to confirm the method. © 2008 Society of Photo-Optical Instrumentation Engineers.

This work presents a new type of MEMS resonator based on launching an acoustic wave around a ring. Its maximum frequency is set by electrode spacing and can therefore provide a means for developing resonators with center frequencies in the GHz. In addition since the center frequency is dependent on the average radius it is not subject to lithographic process variations in ring width. We have demonstrated several Ring Waveguide (RWG) Resonators with center frequencies at 484 MHz and 1 GHz. In addition we have demonstrated a 4th order filter based on a RWG design.