Progress in materials and structures at Lewis Research Center

The development of power and propulsion system technology is discussed. Specific emphasis is placed on the following: high temperature materials; composite materials; advanced design and life prediction; and nondestructive evaluation. Future areas of research are also discussed

Dwell Sensitivity Fatigue Behaviour of High Temperature Materials

The dwell sensitivity fatigue behavior of six high temperature materials is examined in this paper: two stainless steels, 304L and 304, two tantalum alloys, Τ- Ι 11 and ASTAR 811C, pure nickel Ni 201 and a single crystal nickel-base superalloy, PWA 1480. The stainless steel alloys were found to be tensile dwell sensitive; however, a saturation in dwell sensitivity was found with the increase in strain range for all materials examined. At lower strain ranges the dwell cycles were producing lower lives than at higher strains, as found in the case of AISI SS 304 and two tantalum based alloys, T-lll and ASTAR 811C. Trends in various normalized life curves were found to be strain dependent for ASTAR 811C, in which below 0.2% inelastic strain range, dwell effects were more deleterious than above it. Mechanistic aspects under different test conditions were summarized

Can Skills Training Prevent Relationship Problems in At-Risk Couples? Four-Year Effects of a Behavioral Relationship Education Program

Eighty-three couples were stratified into groups at high and low risk for relationship distress and randomized to either the Self-Regulatory Prevention and Relationship Enhancement Program (Self-PREP) or a control condition. As predicted, there were differential effects of Self-PREP on high-risk and low-risk couples. Because of low statistical power, results must be interpreted cautiously, but at 1-year follow-up high-risk couples in Self-PREP showed trends toward better communication than control couples. However, there was no difference in the communication of Self-PREP and control low-risk couples. High-risk couples receiving Self-PREP exhibited higher relationship satisfaction at 4 years than control couples, but in low-risk couples relationship satisfaction was higher in the control condition. High-risk couples seemed to benefit from skills-based relationship education, but low-risk couples did not

Parental divorce and premarital couple communication

On the basis of a social learning analysis, it was hypothesized that a history of parental divorce would predispose partners to difficulties in managing conflict. Ninety-three engaged couples were videotaped while they discussed two areas of conflict. Each partner then completed a video-mediated recall procedure, an assessment of cognition during the interactions, which was then coded and analyzed. As predicted, couples in which the woman's parents had divorced showed more negative communication and cognitions during conflict discussions than did couples in which neither partner's parents had divorced. Contrary to predictions, couples in which the man's parents had divorced did not differ from couples in which neither partner's parents had divorced. The current research shows that, at least for women, a history of parental divorce is associated with more negative couple communication before marriage

A comparison of the generalization of behavioral marital therapy and enhanced behavioral marital therapy

This study examined the generalization of behavioral marital therapy (BMT) and enhanced behavioral marital therapy (EBMT), which added cognitive restructuring, affect exploration, and generalization training to BMT. Couples’ communication and cognitions were assessed in the clinic and at home. Both BMT and EBMT were effective in decreasing negative communication behaviors and cognition across settings, but there was little evidence of differential generalization or change between the treatments. A series of regression equations showed no significant association between the extent of change in communication or cognitions and change in frequency of marital disagreements or marital satisfaction. It is concluded that BMT results in impressive generalization of communication and cognitive change, but it remains to be demonstrated that these changes are crucial to improvements in marital satisfaction

Behavioral Marital Therapy: An Evaluation of Treatment Effects Across High and Low Risk Settings

The present study examined the generalization of treatment effects of a cognitive- behavioral treatment program for marital distress. Following a baseline phase, each of four couples received two phases of marital therapy within a multiple baseline across subject design. The first phase of treatment was behavioral marital therapy (BMT) focusing on communication and problem solving skills. The second phase was cognitive- behavioral marital therapy (CBMT) which focused on conflict management skills in high risk interactive settings at home. Couples’ communication was assessed in a training setting in the clinic and each of two generalization probe settings at home (a low risk and a high risk) setting. The BMT phase produced a clear reduction in communication negativity in the training setting which generalized to both the low and the high risk setting. The CMBT phase produced little additional changes in communication, however, it was associated with changes on a measure of positive and negative partner- referent thoughts

What is the value of short? Exploring the benefits of episodic volunteer experiences for college students

This exploratory study is designed to understand the civic outcomes (e.g., civic-mindedness, intentions to volunteer in the future, and intentions to donate money in the future) for college students who participate in a “Day of Service”. Understanding civic outcomes for college student episodic volunteers helps to justify the investment of staff time devoted to planning and implementing short-term volunteer events by both campus and community-based organizations

Dynamics and consequences of DNA looping by the FokI restriction endonuclease

Genetic events often require proteins to be activated by interacting with two DNA sites, trapping the intervening DNA in a loop. While much is known about looping equilibria, only a few studies have examined DNA-looping dynamics experimentally. The restriction enzymes that cut DNA after interacting with two recognition sites, such as FokI, can be used to exemplify looping reactions. The reaction pathway for FokI on a supercoiled DNA with two sites was dissected by fast kinetics to reveal, in turn: the initial binding of a protein monomer to each site; the protein–protein association to form the dimer, trapping the loop; the subsequent phosphodiester hydrolysis step. The DNA motion that juxtaposes the sites ought on the basis of Brownian dynamics to take ∼2 ms, but loop capture by FokI took 230 ms. Hence, DNA looping by FokI is rate limited by protein association rather than DNA dynamics. The FokI endonuclease also illustrated activation by looping: it cut looped DNA 400 times faster than unlooped DNA

Trauma symptoms, communication, and relationship satisfaction in military couples

Trauma symptoms are negatively correlated with couple relationship satisfaction, which is of particular importance in the relationships of military personnel who are often exposed to trauma whilst on overseas deployment. This study tested a model in which communication mediated an association between trauma symptoms and low relationship satisfaction. Thirty-one Australian military couples were observationally assessed during a communication task, and assessed on their relationship satisfaction and individual functioning. As expected, trauma symptoms in the male military spouse were associated with low satisfaction in both spouses. Females’ low positive communication fully mediated the relationship between males’ trauma symptoms and low female satisfaction, but not male relationship satisfaction. Unexpectedly, males’ negative communication behaviors were associated with high male relationship satisfaction, and partially mediated the association between trauma symptoms and male satisfaction. Discussion focused on how some communication usually thought of as negative might be associated with relationship satisfaction in military couples