Development of microwave NDT inspection techniques for large solid propellant rocket motors Final report

Microwave nondestructive testing techniques for large solid propellant rocket engine

Low-speed wind tunnel investigation of the lateral-directional characterisitcs of a large-scale variable wing-sweep fighter model in the high-lift configuration

The low-speed characteristics of a large-scale model of the F-14A aircraft were studied in tests conducted in the Ames Research Center 40- by 80-Foot Wind Tunnel. The primary purpose of the present tests was the determination of lateral-directional stability levels and control effectiveness of the aircraft in its high-lift configuration. Tests were conducted at wing angles of attack between minus 2 deg and 30 deg and with sideslip angles between minus 12 deg and 12 deg. Data were taken at a Reynolds number of 8.0 million based on a wing mean aerodynamic chord of 2.24 m (7.36 ft). The model configuration was changed as required to show the effects of direct lift control (spoilers) at yaw, yaw angle with speed brake deflected, and various amounts and combinations of roll control

Thermal stability and grain growth behavior of mechanically alloyed nanocrystalline Fe-Cu alloys

X-ray diffraction, transmission electron microscopy, and differential scanning calorimetry were used to study the thermal stability of highly supersaturated nanocrystalline FexCu100−x alloys (10~80. For 60<=x<=80 fcc and bcc phases coexist. Heating to elevated temperatures leads to structural relaxation, phase separation, and grain growth of the metastable nanocrystalline solid solutions. Single-phase fcc and bcc alloys undergo significant strain release but no appreciable grain growth prior to phase separation. After phase separation pronounced grain growth sets in. In contrast, samples in the two-phase region show some grain growth and significant chemical redistribution even at low temperatures. The phase separation of single-phase fcc and bcc alloys proceeds via different mechanisms: fcc solid solutions decompose by forming small Fe precipitates, while demixing in bcc alloys starts by segregation of Cu atoms to bcc grain boundaries before nucleation of Cu precipitates. These results show that the stability and grain growth behavior of nanocrystalline alloys is strongly affected by the microstructure of the material

Parameter trails

Successful communication is vital for the success of any design project. However, communication often fails, adversely affecting design process efficiency and product quality.understand the connections between different aspects of design and don–t know where to find out more information or who to talk to. This paper presents a new model, developed from current project planning techniques, which supports communication using parameter-specific data. It enables designers to question information, inform their colleagues pro-actively and assess the impact of changing parameter values on subsequent design tasks. Such interaction is critical in allowing designers to see how their own tasks fit into the overall product design

Hermetically sealed motion transmitter

Transmitter allows transmission of rotational or single planar arc motion through hermetically sealed chamber without use of dynamic seals or complex mechanisms. Device may interest pressure vessel designers and those who need to isolate equipment from a hostile environment

Ultracold atomic Bose and Fermi spinor gases in optical lattices

We investigate magnetic properties of Mott-insulating phases of ultracold Bose and Fermi spinor gases in optical lattices. We consider in particular the F=2 Bose gas, and the F=3/2 and F=5/2 Fermi gases. We derive effective spin Hamiltonians for one and two atoms per site and discuss the possibilities of manipulating the magnetic properties of the system using optical Feshbach resonances. We discuss low temperature quantum phases of a 87Rb gas in the F=2 hyperfine state, as well as possible realizations of high spin Fermi gases with either 6Li or 132Cs atoms in the F=3/2 state, and with 173Yb atoms in the F=5/2 state.Comment: 15 pages, 5 figures; a completely new and substantially expanded version with several errors correcte

OYSTER ( Crassostrea virginica ) RECRUITMENT STUDIES IN THE GREAT BAY ESTUARY, NEW HAMPSHIRE

Oyster populations in New Hampshire’s Great Bay Estuary have experienced dramatic declines similar to populations along the east coast. These declines have caused ecosystem degradation in estuaries and prompted a focus on oyster reef restoration. Despite the large use of procured funds dedicated for oyster reef restoration, few quantifiable successes have occurred. Currently, there is no rigorous method for determining where a restored reef would have the highest probability for long-term success. However, consistent and substantial natural recruitment is a major factor to consider. In this research, I identify historic trends in oyster populations, quantify the success and failures of restored reefs, and examine how proximity to a native oyster reef affects recruitment. Oyster populations throughout the Great Bay Estuary declined significantly after the introduction of two diseases, MSX and Dermo, in 1995. Although, populations rebounded after large spatfall events, three to four years after these events population levels declined, probably mainly a result of disease. My results suggest oyster recruitment is significantly greater on natural oyster reefs compared to restored reefs. There was also a significant increase in recruitment on restoration reefs less than 1 km from a native reef compared to restoration reefs greater than 1 km from a native reef. Furthermore, recruitment decreased significantly as proximity from a native reef increased. Results suggest that restoration efforts should consider extending the natural boundary of native oyster reefs to provide the greatest potential for natural recruitment and thus long-term reef development