This dissertation describes and tests an Object-Oriented framework, written in Fortran 90, for the Sequential Function Approximation (SFA) algorithm. The SFA algorithm is a meshless method which places its basis functions in the domain sequentially, using optimization techniques. The framework described herein allows the user to define the domain, boundary conditions, and governing equations of 1-D and 2-D problems with minimal user coding, and to solve them using the SFA method. This work advances the state of knowledge in the fields of meshless methods in general and of the SFA method in particular. Unsteady transport problems are solved for the first time with the SFA method: diffusive, convective-diffusive, and purely convective problems are solved using a semi-discrete approach and stabilized with the Streamline-Upwind Petrov-Galerkin (SUPG) technique. Additionally, some light is shed on the role of consistency. SFA is placed within the broader context of meshless methods, and made consistent by transforming it into a sequentially solved Partition of Unity (POU) method. Consistency is experimentally found to improve the convergence behavior of all model problems solved. The improvement is most notable in problems with convection phenomena, although some improvement is seen even in purely diffusive problems. Other hypotheses regarding the SFA method are investigated as well.

The optical response of sulfuric acid anodized 5657 aluminum alloy coatings was determined to be greatly dependent upon trace and alloying element concentration. An improved method for WDS analysis of anodized coatings was developed to preclude processing errors and improve spatial resolution since it was shown that the possibility of contamination and/or coating modification must be considered in the development of sample preparation procedures and electron beam parameters. Measured element concentrations were compared with reflectance data to determine the affect of each on absorptance. Silicon and zinc concentrations were much higher than expected, the source of these elements being the substrate 5657 Al alloy. Both of these elements play a role in absorptance and the glass forming abilities of silicon may also affect the structural characteristics of SAA coatings produced on 5657 Al alloy.

This research presents the concept of an Enhanced and Synthetic Vision System (ESVS) that could help aircraft pilots see in low visibility conditions. The basic idea is that synthetic and infrared imagery would be fused to maximize image content. Three fusion algorithms were implemented and tuned for this particular purpose. Artificially generated infrared images as well as synthetic images were used to evaluate the algorithms' performance. An observer experiment, based on a typical search and rescue scenario, showed that image fusion leads to an increase in useful information. Different registration conditions were also simulated to investigate their effect on a potential ESVS.

In order to keep up with the ever-increasing demand in communications, photonic technology, that has potential benefits in low power consumption, large bandwidth, reduction in payload mass and volume, and electromagnetic interference immunity, offers an alternative approach for the future communication satellites. An optical multi-carrier demultiplexer/demodulator (MCDD) system using acousto-optic technology has been built and characterized for satellite on-board processing (OBP). In this work, the design and implementation of this demonstrator are presented. The challenges for introducing the optical technologies are also discussed for the optics, optical packaging, and opto-electronics. The system was characterized and demonstrated a channel capacity of 438 channels with a power consumption of 63.9mW per channel.

<p> The need to identify the factors that influence the overall safety environment and compliance with safety procedures within airline operations is substantial. This study examines the relationships between job satisfaction, the overall perception of the safety culture, and compliance with safety rules and regulations of airline employees working in flight operations. A survey questionnaire administered via the internet gathered responses which were converted to numerical values for quantitative analysis. The results were grouped to provide indications of overall average levels in each of the three categories, satisfaction, perceptions, and compliance. Correlations between data in the three sets were tested for statistical significance using two-sample t-tests assuming equal variances. Strong statistical significance was found between job satisfaction and compliance with safety rules and between perceptions of the safety environment and safety compliance. The relationship between job satisfaction and safety perceptions did not show strong statistical significance.</p>

<p> Nanofluids, stable colloidal suspensions of nanoparticles in a base fluid, have potential applications in the heat transfer, combustion and propulsion, manufacturing, and medical fields. Experiments were conducted to determine the evaporation rate of room temperature, millimeter-sized pendant drops of ethanol laden with varying amounts (0-3% by weight) of 40-60 nm aluminum nanoparticles (nAl). Time-resolved high-resolution drop images were collected for the determination of early-time evaporation rate (D²/D₀² > 0.75), shown to exhibit D-square law behavior, and surface tension. Results show an asymptotic decrease in pendant drop evaporation rate with increasing nAl loading. The evaporation rate decreases by approximately 15% at around 1% to 3% nAl loading relative to the evaporation rate of pure ethanol. Surface tension was observed to be unaffected by nAl loading up to 3% by weight. </p><p> A model was developed to describe the evaporation of the nanofluid pendant drops based on D-square law analysis for the gas domain and a description of the reduction in liquid fraction available for evaporation due to nanoparticle agglomerate packing near the evaporating drop surface. Model predictions are in relatively good agreement with experiment, within a few percent of measured nanofluid pendant drop evaporation rate. </p><p> The evaporation of pinned nanofluid sessile drops was also considered via modeling. It was found that the same mechanism for nanofluid evaporation rate reduction used to explain pendant drops could be used for sessile drops. That mechanism is a reduction in evaporation rate due to a reduction in available ethanol for evaporation at the drop surface caused by the packing of nanoparticle agglomerates near the drop surface. Comparisons of the present modeling predictions with sessile drop evaporation rate measurements reported for nAl/ethanol nanofluids by Sefiane and Bennacer [11] are in fairly good agreement. Portions of this abstract previously appeared as: W. J. Gerken, A. V. Thomas, N. Koratkar and M. A. Oehlschlaeger, Int. J. Heat Mass Transfer, vol. 74, no. 1, pp. 263-268, July 2014. W. J. Gerken, M. A. Oehlschlaeger, "Nanofluid Pendant Droplet Evaporation", in Proceedings of the ASME 2013 Summer Heat Transfer Conference, Minneapolis, MN, 2013, pp. V001T03A018.</p>

The research work presented in this thesis deals with flight control problems. Based on robust control techniques such as H infinity control and mu-synthesis, we develop control laws that are efficient in reducing gust loads on flexible aircraft. Uncertainty models for flexible aircraft are proposed and shown to be well adapted for robust control design, while tightly covering unknown but bounded variations of flexible mode parameters. One of the models presented introduces a new complex-rational controller design methodology that takes advantage of the uncertain plant structure and achieves good performance criteria. Other uncertainty models are presented for the first time for the purpose of closed-loop reduction of flexible models. We propose a new model/controller order reduction method for flexible aircraft preserving robust performance in closed loop. Two case studies of complex aircraft are presented with the objective of full flight envelope control. Solutions for scheduled control laws are given to maintain performance objectives along the entire flight envelope. We adapt to our complex aircraft case study known gain scheduling techniques such as observer-form controller scheduling, and we propose new gain scheduling techniques, including a robust performance blending/interpolation design, an optimal multi-switching methodology and a scheduled-partitioned controller.

This thesis presents a more accurate and efficient method for the study of finite span wings in steady and unsteady supersonic flows with more computing efficiency. / For steady flows, the boundary conditions are expressed in terms of the source distributions over wing surfaces. Specific theoretical solutions are derived for the calculations of pressure coefficient distribution and the lift, pitching moment, and rolling moment coefficients. The present solutions have been validated for delta and trapezoidal wings by comparison with high order conical flow results based on the theory developed by Carafoli, Mateescu, and Nastase. An excellent agreement was found between these results. / For unsteady flows, the boundary conditions of finite span wings are modeled by using pulsating sources distributing over the wing surface. The present method leads to more accurate solutions for rigid wings executing harmonic oscillations in translation, pitching rotation, and rolling rotation of various oscillating frequencies. These solutions were found in very good agreement with the available high order conical flow solutions obtained by Carafoli, Mateescu, and Nastase. / Then the method has been used to obtain solutions for the flexible wings executing flexural oscillations, which are of interest for the aeroelastic studies in the aeronautical applications.

Thesis (Ph.D.)--California Institute of Technology, 2005. / (UnM)AAI3197372. Source: Dissertation Abstracts International, Volume: 66-11, Section: B, page: 6095. Adviser: Dale I. Pullin.

Thesis (Ph.D.)--California Institute of Technology, 2005. / (UnM)AAI3197342. Source: Dissertation Abstracts International, Volume: 66-12, Section: B, page: 6748. Adviser: D. I. Pullin.