Wright-Patterson Air Force Base

About: Wright-Patterson Air Force Base is a other organization based out in Wright-Patterson AFB, Ohio, United States. It is known for research contribution in the topics: Laser & Microstructure. The organization has 5817 authors who have published 9157 publications receiving 292559 citations. The organization is also known as: Wright-Patterson AFB & FFO.

An adaptive array for interference rejection

Abstract: An adaptive array that rejects undesired or interfering signals is presented. The array pattern is controlled by an adaptive feedback system based on a steepest descent minimization of mean-square error. Error is defined as the difference between the array output and a locally generated reference signal. Minimization of mean-square error is closely related to maximization of signal-to-noise ratio (SNR). A two-element adaptive array has been built, and its experimental performance is discussed. Typical patterns for various desired and interfering signals are shown, as well as measured transient response. Finally, some experiments showing the array behavior with modulated signals are described. The results show that such an antenna system is capable of automatically rejecting interfering signals, subject only to certain basic constraints. No a priori information about the angles of arrival of the signals is required, Detailed knowledge of the waveforms of the desired and interfering signals is also not needed, although the spectral characteristics of the desired signal must be known.

Fitting Models to Composite Materials Fatigue Data

Abstract: A new procedure for fitting fatigue models (consisting of a deterministic equation defining the shape of the S-N curve and a probabilistic description of the data scatter) is presented. The procedure consists of (1) transforming the fatigue data into equivalent static strength data by using the deterministic equation in the fatigue model with unknown parameters, (2) obtaining the maximum-likelihood estimates for the parameters of the (two-parameter Weibull) distribution describing the equivalent static strength data, and (3) repeating Steps 1 and 2 until the largest maximum-likelihood estimate of the shape parameter is obtained. The procedure can handle runouts and tab failures through progressive censoring. Finally, the procedure is well defined when small fatigue data samples are available.

Role of Flow Visualization in the Development of UNICORN

Abstract: This paper describes how visualizations have been used in the development and evaluation of a reacting-flow-simulation model known as UNICORN (UNsteady Ignition and COmbustion with ReactioNs). UNICORN, which solves full Navier-Stokes equations, has evolved over a 6-year period and is perhaps one of the most thoroughly evaluated codes of its kind. It evolved hand-in-hand with experiments that have been conducted to test its ability to predict ignition, extinction, and the dynamic characteristics of diffusion and premixed flames of hydrogen, methane, and propane fuels and that are stabilized in different ways. This paper also describes how UNICORN has been used, in conjunction with experiments, to provide new insights into combusting flows. Also, predictions of unobserved phenomena that were later confirmed by experiments are described. This paper demonstrates that the judicious use of a well-validated simulation in conjunction with laser based diagnostics is an effective way of understanding complex combusting flows.

Exploration of Plasma-Enhanced Chemical Vapor Deposition as a Method for Thin-Film Fabrication with Biological Applications

Abstract: Chemical vapor deposition (CVD) has been used historically for the fabrication of thin films composed of inorganic materials. But the advent of specialized techniques such as plasma-enhanced chemical vapor deposition (PECVD) has extended this deposition technique to various monomers. More specifically, the deposition of polymers of responsive materials, biocompatible polymers, and biomaterials has made PECVD attractive for the integration of biotic and abiotic systems. This review focuses on the mechanisms of thin-film growth using low-pressure PECVD and current applications of classic PECVD thin films of organic and inorganic materials in biological environments. The last part of the review explores the novel application of low-pressure PECVD in the deposition of biological materials.