Surface protection of graphite fabric/PMR-15 composites subjected to thermal oxidation

Graphite fabric/PMR-15 laminates develop matrix cracks during long-term exposure in air at temperatures in the range of 500 to 600 F. This study was performed to demonstrate the effectiveness of incorporating graphite mat surface plies as a means of reducing the developing of matrix cracks. Celion 3000 graphite fabric/PMR-15 laminates were fabricated with graphite or graphite mat/325-mesh boron powder surface plies. Laminates without mat surface plies were also fabricated for control purposes. Composite flexural strength, flexural modulus, and interlaminar shear strength were determined at 288 C before and after long-term exposure (up to 1500 hr) in air at 316 C. The results of this study showed that the incorporation of graphite mat surface plies reduces matrix cracking and improves the elevated temperature mechanical property retention characteristics of the composites

Helium compressors for closed-cycle, 4.5-Kelvin refrigerators

An improved helium compressor for traveling-wave maser and closed-cycle refrigerator systems was developed and is currently being supplied to the DSN. This new 5-hp compressor package is designed to replace the current 3-hp DSN compressors. The new compressor package was designed to retrofit into the existing 3-hp compressor frame and reuse many of the same components, therefore saving the cost of documenting and fabricating these components when implementing a new 5-hp compressor

Equations to assess the impact resistance of fiber composites

Numerical analysis of impact resistance of composite materials containing fibers is discussed. Mathematical model of longitudinal impact resistance is presented. Potential impact resistance of various fiber composites as obtained by numerical analysis is presented as plotted curve

Bonding of strain gages to fiber reinforced composite plastic materials

Strain gage is installed during molding of composite and utilizes the adhesive properties of the matrix resin in the composite to bond the strain gage in place. Gages thus embedded provide data at all temperatures that the matrix can withstand

Criteria for selecting resin matrices for improved composite strength

Area under matrix of typical stress-strain diagram bounded by one percent strain is good index for priority assessment of matrix contribution to composite strength. Initial tangent modulus to stress-strain curve is useful parameter in translating matrix properties to composite properties

Social support, social control and health behavior change in spouses

Our work on support processes in intimate relationships has focused on how partners in committed relationships help one another contend with personal difficulties, and how partners elicit and provide support in their day-to-day interactions. We are particularly interested in how these support skills relate to marital outcomes (Pasch & Bradbury, 1998; Pasch, Harris, Sullivan, & Bradbury, 2004; Sullivan, Pasch, Eldridge, & Bradbury, 1998) and how they relate to behavior change in spouses (Sullivan, Pasch, Johnson, & Bradbury, 2006), especially health behavior changes. In this chapter, we review research examining the effects of social support and social control on spouses\u27 health behaviors, propose a theory to account for discrepancies in these findings, and report initial data examining the usefulness of this theory in understanding the relationship between social support, social control, and partner health behavior