HOST instrumentation R and D program overview

The HOST Instrumentation R and D program is focused on two categories of instrumentation. One category is that required to characterize the environment imposed on the hot section components of turbine engines. This category includes instruments for measuring gas flow, gas temperature, and heat flux. The second category is that for measuring the effect of the environment on the hot section components. This category includes strain measuring instruments and an optical system for viewing the interior of an operating combustor to detect cracks, buckling, carbon buildup, etc

Research instrumentation for hot section components of turbine engines

Programs to develop research instrumentation for use on hot section components of turbine engines are discussed. These programs can be separated into two categories: one category includes instruments which can measure the environment within the combustor and turbine components, the other includes instruments which measure the response of engine components to the imposed environment. Included in the first category are instruments to measure total heat flux and fluctuating gas temperature. High temperature strain measuring systems, thin film sensors (e.g., turbine blade thermocouples) and a system to view the interior of a combustor during engine operation are programs which comprise the second category. The paper will describe the state of development of these sensors and measuring systems and, in some cases, show examples of measurements made with this instrumentation. The discussion will cover work done at NASA Lewis and at various contractor facilities

Nonlinear Temporal Dynamics of Strongly Coupled Quantum Dot-Cavity System

We theoretically analyze and simulate the temporal dynamics of strongly coupled quantum dot-cavity system driven by a resonant laser pulse. We observe the signature of Rabi oscillation in the time resolved response of the system (i.e., in the numerically calculated cavity output), derive simplified linear and non-linear semi-classical models that approximate well the system's behavior in the limits of high and low power drive pulse, and describe the role of quantum coherence in the exact dynamics of the system. Finally, we also present experimental data showing the signature of the Rabi oscillation in time domain

Dynamics of short pressure probes

Report presents practical information for incorporating particle impact protection features and average total pressure measurement into probe design while optimizing probe transient response. Computer program calculates probe response, based on Bergh-Tijdeman equation

Advanced high temperature instrument for hot section research applications

Programs to develop research instrumentation for use in turbine engine hot sections are described. These programs were initiated to provide improved measurements capability as support for a multidisciplinary effort to establish technology leading to improved hot section durability. Specific measurement systems described here include heat flux sensors, a dynamic gas temperature measuring system, laser anemometry for hot section applications, an optical system for viewing the interior of a combustor during operation, thin film sensors for surface temperature and strain measurements, and high temperature strain measuring systems. The state of development of these sensors and measuring systems is described, and, in some cases, examples of measurements made with these instruments are shown. Work done at the NASA Lewis Research Center and at various contract and grant facilities is covered

The infinite line pressure probe

The infinite line pressure probe provides a means for measuring high frequency fluctuating pressures in difficult environments. A properly designed infinite line probe does not resonate; thus its frequency response is not limited by acoustic resonance in the probe tubing, as in conventional probes. The characteristics of infinite line pressure probes are reviewed and some applications in turbine engine research are described. A probe with a flat-oval cross section, permitting a constant-impedance pressure transducer installation, is described. Techniques for predicting the frequency response of probes with both circular and flat-oval cross sections are also cited

Sinusoidal-pressure generator for testing dynamic pressure probes

Generator can produce sinusoidal pressures at frequencies from 300 to 5000 Hz and peak-to-peak amplitudes up to 5.6 lbs/sq in. Amplitude and phase-angle measurements made at various frequencies are compared with measurements from a piezoelectric transducer mounted flush with the resonant tube wall

An Exploration of the Status Quo Bias in Nonhuman Primates

A status quo bias is a tendency to resist change and keep things as they are. This bias is robust in humans and likely a byproduct of heuristic decision-making mechanisms, indicating that it may be an evolutionarily-conserved process that is phylogenetically widespread. However, few status quo bias studies have been conducted with nonhuman animals, and the evidence was mixed. Studying this question with animals could help inform welfare decisions for animals directly and it can shed light on the degree to which a status quo bias (as seen in humans) may be a result of human-unique experiences or the consequence of more fundamental decision-making mechanisms. The goal of this study was to explore whether other primates exhibit a preference for the status quo after controlling for reinforcement history, and to explore the relative influence of several different factors that may moderate the status quo bias effect. To test these questions, I conducted two experiments. In Experiment 1, capuchin monkeys and macaques made choices among computerized tasks, where one task was presented as the ‘default’ option (i.e., it could be played continuously without having to select it from a menu), after forced runs of trials that varied in length and which included trials of either a single task type or a mix of task types. I predicted that the monkeys would demonstrate a general preference for the default task over non- default alternatives, and that this preference would increase in magnitude after longer forced runs of the default task. In Experiment 2, lemurs and tamarins learned that boxes could be opened in two ways (lifting or sliding). I explored whether animals could be influenced to open the box by using one particular mechanism after recent exposure to that mechanism (i.e., establishing it as the ‘status quo’) while controlling overall reinforcement history for both mechanisms. The results indicated that the animals did not exhibit a status quo bias in these paradigms; other factors such as variety and task preference (E1) and approach angle (E2) had greater influence on animals’ choice behavior than the established status quo

Global atmospheric sampling program

Automated instruments were installed on a commercial B-747 aircraft, during the program, to obtain baseline data and to monitor key atmospheric constituents associated with emissions of aircraft engines in order to determine if aircraft are contributing to pollution of the upper atmosphere. Data thus acquired on a global basis over the commercial air routes for 5 to 10 years will be analyzed. Ozone measurements in the 29,000 to 45,000 foot altitude were expanded over what has been available from ozonesondes. Limited aerosol composition measurements from filter samples show low levels of sulfates and nitrates in the upper troposphere. Recently installed instruments for measurement of carbon monoxide and condensation nuclei are beginning to return data