PC programs for the prediction of the linear stability behavior of liquid propellant propulsion systems and application to current MSFC rocket engine test programs, volume 1

Research on propulsion stability (chugging and acoustic modes), and propellant valve control was investigated. As part of the activation of the new liquid propulsion test facilities, it is necessary to analyze total propulsion system stability. To accomplish this, several codes were built to run on desktop 386 machines. These codes enable one to analyze the stability question associated with the propellant feed systems. In addition, further work was adapted to this computing environment and furnished along with other codes. This latter inclusion furnishes those interested in high frequency oscillatory combustion behavior (that does not couple to the feed system) a set of codes for study of proposed liquid rocket engines

DIEL PERIODICITY OF MALE SEX PHEROMONE RESPONSE AND FEMALE ATTRACTIVENESS IN THE GYPSY MOTH (LEPIDOPTERA: LYMANTRIIDAE)

In field studies gypsy moth males were attracted to synthetic cis-7,8-epoxy-2-methyloctadecane (disparlure), the female sex pheromone, and virgin females from 0900 to 2000 (Eastern Standard Time). The greatest numbers of males were lured to the synthetic attractant or the calling female from 1100 to 1500. These periods of male response are longer than reported in previous (1896 and 1932) New England investigations and suggest the possible recent evolution of a new diel rhythm of male sex pheromone respons

Propulsion stability codes for liquid propellant propulsion systems developed for use on a PC computer

Research into component modeling and system synthesis leading to the analysis of the major types of propulsion system instabilities and the characterization of various components characteristics are presented. Last year, several programs designed to run on a PC were developed for Marshall Space Flight Center. These codes covered the low, intermediate, and high frequency modes of oscillation of a liquid rocket propulsion system. No graphics were built into these programs and only simple piping layouts were supported. This year's effort was to add run time graphics to the low and intermediate frequency codes, allow new types of piping elements (accumulators, pumps, and split pipes) in the low frequency code, and develop a new code for the PC to generate Nyquist plots

Stability codes for a liquid rocket implemented for use on a PC

The high frequency code has been made an interactive code using FORTRAN 5.0. The option to plot n-tau curves was added using the graphics routines of FORTRAN 5.0 and GRAFMATIC. The user is now able to run with input values non-dimensional (as in the original code) or dimensional. Input data may be modified from the keyboard. The low and intermediate frequency codes have been run through a set of variations. This will help the user to understand how the stability of a configuration will change if any of the input data changes

Attractancy of Racemic Disparlure and Certain Analogues to Male Gypsy Moths and the Effect of Trap Placement

Traps hung on small trees of 3-8 cm diam and baited with racemic epoxides, hydrocarbons and other analogues related to racemic cis-7,8-epoxy-2-methyloctadecane (disparlure) resulted in male Lymantria dispar L. (gypsy moth) catches statistically indistinguishable from those of unbaited traps. Only (±)-disparlure yielded trap catches statistically above the level of unbaited traps. However, trap placement on trees of ca. 0.5 m diam produced appreciable trap catches, even in unbaited trap

Problematizing Choice: Responsible consumers and sceptical citizens

About the book: Governance, Consumers and Citizens is the first book to bring together a study of governance with consumption, examining the changing place of the consumer as citizen in recent trends in governance, the tensions between competing ideas and practices of consumerism and the active role consumers play in the construction and practice of governance. Radically pushing forward the debate on consumers and governance, this collection outlines new conceptions and posits new policy agendas. Bringing together international experts from political science, history, geography, social policy and media studies, this study shows how governance and consumption are intertwined in crucial aspects of public policy and contemporary politics

Development and Testing of a High Stability Engine Control (HISTEC) System

Flight tests were recently completed to demonstrate an inlet-distortion-tolerant engine control system. These flight tests were part of NASA's High Stability Engine Control (HISTEC) program. The objective of the HISTEC program was to design, develop, and flight demonstrate an advanced integrated engine control system that uses measurement-based, real-time estimates of inlet airflow distortion to enhance engine stability. With improved stability and tolerance of inlet airflow distortion, future engine designs may benefit from a reduction in design stall-margin requirements and enhanced reliability, with a corresponding increase in performance and decrease in fuel consumption. This paper describes the HISTEC methodology, presents an aircraft test bed description (including HISTEC-specific modifications) and verification and validation ground tests. Additionally, flight test safety considerations, test plan and technique design and approach, and flight operations are addressed. Some illustrative results are presented to demonstrate the type of analysis and results produced from the flight test program

The Impact of Laser Control on The Porosity And Microstructure of Selective Laser Melted Nickel Superalloy 718

Additively manufacturing high performance metals by laser processing represents an exciting opportunity to exploit localized properties by varying input parameters throughout the process. This work explores the solidification and microstructural properties of selectively laser melted (SLM) Inconel 718 (IN718) using unique processing parameters. By employing traditional pulsed laser physics techniques, samples were manufactured with a continuous wave laser to study a potential ubiquitous approach. While the overall power density was controlled, the power, speed, and hatch spacing were varied. The porosity and grain sizes of the samples were characterized by optical and scanning electron microscopes. The influence of processing parameters showed physical differences in the final samples. Sample degradation was observed in higher power processes with porosity up 10%, likely due to increased temperatures and more intense thermal gradients

Status of the PICASSO Project

The Picasso project is a dark matter search experiment based on the superheated droplet technique. Preliminary runs performed at the Picasso Lab in Montreal have showed the suitability of this detection technique to the search for weakly interacting cold dark matter particles. In July 2002, a new phase of the project started. A batch of six 1-liter detectors with an active mass of approximately 40g was installed in a gallery of the SNO observatory in Sudbury, Ontario, Canada at a depth of 6,800 feet (2,070m). We give a status report on the new experimental setup, data analysis, and preliminary limits on spin-dependent neutralino interaction cross section.Comment: 3 pages, 2 figures. To appear in the Proceedings of the TAUP 2003 conference, 5-9 September, 2003, University of Washington, Seattle, US