70 Years of Aeropropulsion Research at NASA Glenn Research Center

This paper presents a brief overview of air-breathing propulsion research conducted at the NASA Glenn Research Center (GRC) over the past 70 years. It includes a historical perspective of the center and its various stages of propulsion research in response to the countrys different periods of crises and growth opportunities. GRCs research and technology development covered a broad spectrum, from a short-term focus on improving the energy efficiency of aircraft engines to advancing the frontier technologies of high-speed aviation in the supersonic and hypersonic speed regimes. This paper highlights major research programs, showing their impact on industry and aircraft propulsion, and briefly discusses current research programs and future aeropropulsion technology trends in related area

An Overview of Low-Emission Combustion Research at NASA Glenn

An overview of research efforts at NASA Glenn Research Center (GRC) in low-emission combustion technology that have made a significant impact on the nitrogen oxides (NOx) emission reduction in aircraft propulsion is presented. The technology advancements and their impact on aircraft emissions are discussed in the context of NASA's Aeronautics Research Mission Directorate (ARMD) high-level goals in fuel burn, noise and emission reductions. The highlights of the research presented here show how the past and current efforts laid the foundation for the engines that are flying today as well as how the continued technology advancements will significantly influence the next generation of aviation propulsion system designs

ESSAYS ON TRADE, IMMIGRATION, AND MICROFINANCE

This dissertation consists of three papers analyzing the effect of the South Asian free trade agreement, identifying various factors that influence the settlement of illegal immigrants and the impact of microfinance on investment in children's education. The first article estimates the effect of a free trade agreement on export flows among member countries of the South Asian Free Trade Area (SAFTA) using panel data from 2001 - 2010. This paper also compares the average growth of exports of SAFTA countries with neighboring non-SAFTA countries using difference-in-differences Poisson Pseudo Maximum Likelihood gravity estimator. Results show that the share of intraregional exports has grown within SAFTA during the post-SAFTA period compared to the pre-SAFTA period by 107 percent. But I find that the increase in exports in SAFTA is not statistically different from the increase in exports of the Association of Southeast Asian Nations.The second study identifies various important characteristics that determine the location of illegal immigrants within the United States. I use random effect model to investigate the various reasons why illegal immigrants decide to settle in different states including socioeconomic, network, welfare, political, and enforcement effects. I find that illegal immigrants settle in states with network effects, where the enforcement is higher; and are less likely to be in states with a higher welfare effects. I used a logit model to examine personal characteristics on the illegal immigrants. I find that illegal immigrants are more likely to be males, with low education levels, working in the construction sector.The third study estimates how the probability of taking a microfinance loan and the total amount of loan from microfinance institutions by Self Help Groups members affects their children's education in India. The objective of this study is to identify the factors that determine the probability of getting a loan from microfinance institutions using probit model. Results show that household income has positive impact on probability of getting a microfinance loan, but did not find any effect on savings and expenditure. The analysis did not find any evidence of the impact of microfinance credit of household members on investment in children's education

Theta-Pinch Thruster for Piloted Deep Space Exploration

A new high-power propulsion concept that combines a rapidly pulsed theta-pinch discharge with upstream particle reflection by a magnetic mirror was evaluated under a Phase 1 grant awarded through the NASA Institute for Advanced Concepts. Analytic and numerical models were developed to predict the performance of a theta-pinch thruster operated over a wide range of initial gas pressures and discharge periods. The models indicate that a 1 m radius, 10 m long thruster operated with hydrogen propellant could provide impulse-bits ranging from 1 N-s to 330 N-s with specific impulse values of 7,500 s to 2,500 s, respectively. A pulsed magnetic field strength of 2 T is required to compress and heat the preionized hydrogen over a 10(exp -3) second discharge period, with about 60% of the heated plasma exiting the chamber each period to produce thrust. The unoptimized thruster efficiency is low, peaking at approximately 16% for an initial hydrogen chamber pressure of 100 Torr. The specific impulse and impulse-bit at this operating condition are 3,500 s and 90 N-s, respectively, and the required discharge energy is approximately 9x10(exp 6) J. For a pulse repetition rate of 10 Hz, the engine would produce an average thrust of 900 N at 3,500 s specific impulse. Combined with the electrodeless nature of the device, these performance parameters indicate that theta-pinch thrusters could provide unique, long-life propulsion systems for piloted deep space mission applications

Antimatter Production at a Potential Boundary

Current antiproton production techniques rely on high-energy collisions between beam particles and target nuclei to produce particle and antiparticle pairs, but inherently low production and capture efficiencies render these techniques impractical for the cost-effective production of antimatter for space propulsion and other commercial applications. Based on Dirac's theory of the vacuum field, a new antimatter production concept is proposed in which particle-antiparticle pairs are created at the boundary of a steep potential step formed by the suppression of the local vacuum fields. Current antimatter production techniques are reviewed, followed by a description of Dirac's relativistic quantum theory of the vacuum state and corresponding solutions for particle tunneling and reflection from a potential barrier. The use of the Casimir effect to suppress local vacuum fields is presented as a possible technique for generating the sharp potential gradients required for particle-antiparticle pair creation

Disaster Assistance and Crop Insurance Participation in US

This research examined factors influencing farmer purchase of crop insurance and receipt of disaster assistance payments using survey data for more than 13,000 farms across 27 U.S. states. Using a bivariate probit model some main findings are as follows. The probability of participating in federal crop insurance programs is (a) lower for farmers more than 65 years of age; (b) increasing with farmer education and farm sales; (c) lower for farms where farm income is a small share of household income; and (d) higher in states with higher average temperatures and lower average precipitation. The probability of receiving disaster payments (a) increases as farms depend more on farm income for their total household income; (b)increases with sales in peanut farming and cattle ranching; (c) greater in states experiencing drier or wetter than normal hydrologic conditions; and (d) greater in states experiencing warmer than normal temperatures. In addition, previous research using state-level data found agricultural disaster payments were higher in states with congressional representation on subcommittees overseeing USDA’s direct disaster payment program. The farm-level analysis of this thesis supports this earlier finding. Farmers in states with such representation had higher probabilities of receiving disaster payments, controlling for other factors

High Power MPD Thruster Development at the NASA Glenn Research Center

Propulsion requirements for large platform orbit raising, cargo and piloted planetary missions, and robotic deep space exploration have rekindled interest in the development and deployment of high power electromagnetic thrusters. Magnetoplasmadynamic (MPD) thrusters can effectively process megawatts of power over a broad range of specific impulse values to meet these diverse in-space propulsion requirements. As NASA's lead center for electric propulsion, the Glenn Research Center has established an MW-class pulsed thruster test facility and is refurbishing a high-power steady-state facility to design, build, and test efficient gas-fed MPD thrusters. A complimentary numerical modeling effort based on the robust MACH2 code provides a well-balanced program of numerical analysis and experimental validation leading to improved high power MPD thruster performance. This paper reviews the current and planned experimental facilities and numerical modeling capabilities at the Glenn Research Center and outlines program plans for the development of new, efficient high power MPD thrusters