Compendium of fracture mechanics problems

Fracture mechanics analysis results are presented from the following structures/components analyzed at Marshall Space Flight Center (MSFC) between 1982 and 1989: space shuttle main engine (SSME), Hubble Space Telescope (HST), external tank attach ring, B-1 stand LOX inner tank, and solid rocket booster (SRB). Results from the SSME high pressure fuel turbopump (HPFTP) second stage blade parametric analysis determine a critical flaw size for a wide variety of stress intensity values. The engine 0212 failure analysis was a time dependent fracture life assessment. Results indicated that the disk ruptured due to an overspeed condition. Results also indicated that very small flaws in the curvic coupling area could propagate and lead to failure under normal operating conditions. It was strongly recommended that a nondestructive evaluation inspection schedule be implemented. The main ring of the HST, scheduled to launch in 1990, was analyzed by safe-life and fail-safe analyses. First safe-life inspection criteria curves for the ring inner and outer skins and the fore and aft channels were derived. Afterwards the skins and channels were determined to be fail-safe by analysis. A conservative safe-life analysis was done on the 270 redesign external tank attach ring. Results from the analysis were used to determine the nondestructive evaluation technique required

Examining The Communication Strategies Utilized During An Organizational Change Within Universities’ Branch Campuses

In this interpretive phenomenological study, the researcher sought to understand the lived experiences of branch campus administrators’ perceptions of the communication strategies utilized during a pervasive organizational change. Minimal research has been conducted surrounding the specifics of the communication strategies that have effectively and successfully matriculated branch campus administrators through an organizational change. To gain a better understanding of the lived experiences and perceptions of the communication strategies utilized during a branch campus organizational change, 35 members of the National Association of Branch Campus Administrators completed a qualifying survey. A semistructured interview was conducted with 10 branch campus administrators who had worked at a nonprofit, 4-year, regionally accredited university within the United States and had experienced a branch campus organizational change within the last five years. Data collected from the interviews revealed that there were connections between the organizational relationship of the main campus with its branch campuses and participant perceptions of the effectiveness of the communication strategies utilized. Furthermore, branch campus leaders played an intricate role in how well their teams received information, remained motivated during the organizational change, and successfully matriculated through the change. Lastly, empathetic communication emerged as a necessary component when branch campus administrators engaged with their staff throughout the organizational change

Mesoscopic phase separation in Nax_xCoO2_2 (0.65≤x≤0.750.65\leq x\leq 0.75)

NMR, EPR and magnetization measurements in Na$_x$CoO$_2$ for $0.65\leq x\leq 0.75$ are presented. While the EPR signal arises from Co$^{4+}$ magnetic moments ordering at $T_c\simeq 26$ K, $^{59}$Co NMR signal originates from cobalt nuclei in metallic regions with no long range magnetic order and characterized by a generalized susceptibility typical of strongly correlated metallic systems. This phase separation in metallic and magnetic insulating regions is argued to occur below $T^*(x)$ ($220 - 270$ K). Above $T^*$ an anomalous decrease in the intensity of the EPR signal is observed and associated with the delocalization of the electrons which for $T<T^*$ were localized on Co$^{4+}$ $d_{z^2}$ orbitals. It is pointed out that the in-plane antiferromagnetic coupling $J\ll T^*$ cannot be the driving force for the phase separation.Comment: 14 figure

Nano-Particle Enhanced Polymer Materials for Space Flight Applications

Recent advances in materials technology both in polymer chemistry and nano-materials warrant development of enhanced structures for space flight applications. This work aims to develop spacecraft structures based on polymer matrix composites (PMCs) that utilize these advancements.. Multi-wall carbon nano-tubes (MWCNTs) are expected to increase mechanical performance, lower coefficient of thermal expansion (CTE), increase electrical conductivity (mitigate electrostatic charge), increase thermal conductivity, and reduce moisture absorption of the resultant space structures. In this work, blends of MWCNTs with PETI-330 were prepared and characterized. The nano-reinforced resins were then resin transfer molded (RTM) into composite panels using M55J carbon fabric and compared to baseline panels fabricated from a cyanate ester (RS-3) or a polyimide (PETI-330) resin containing no MWCNTs. In addition, methods of pre-loading the fabric with the MWCNTs were also investigated. The effects of the MWCNTs on the resin processing properties and on the composite end-use properties were also determined

An exploratory study to examine intentions to adopt an evidence-based HIV linkage-to-care intervention among state health department AIDS directors in the United States

<p>Abstract</p> <p>Background</p> <p>Widespread dissemination and implementation of evidence-based human immunodeficiency virus (HIV) linkage-to-care (LTC) interventions is essential for improving HIV-positive patients' health outcomes and reducing transmission to uninfected others. To date, however, little work has focused on identifying factors associated with intentions to adopt LTC interventions among policy makers, including city, state, and territory health department AIDS directors who play a critical role in deciding whether an intervention is endorsed, distributed, and/or funded throughout their region.</p> <p>Methods</p> <p>Between December 2010 and February 2011, we administered an online questionnaire with state, territory, and city health department AIDS directors throughout the United States to identify factors associated with intentions to adopt an LTC intervention. Guided by pertinent theoretical frameworks, including the Diffusion of Innovations and the "push-pull" capacity model, we assessed participants' attitudes towards the intervention, perceived organizational and contextual demand and support for the intervention, likelihood of adoption given endorsement from stakeholder groups (<it>e.g</it>., academic researchers, federal agencies, activist organizations), and likelihood of enabling future dissemination efforts by recommending the intervention to other health departments and community-based organizations.</p> <p>Results</p> <p>Forty-four participants (67% of the eligible sample) completed the online questionnaire. Approximately one-third (34.9%) reported that they intended to adopt the LTC intervention for use in their city, state, or territory in the future. Consistent with prior, related work, these participants were classified as LTC intervention "adopters" and were compared to "nonadopters" for data analysis. Overall, adopters reported more positive attitudes and greater perceived demand and support for the intervention than did nonadopters. Further, participants varied with their intention to adopt the LTC intervention in the future depending on endorsement from different key stakeholder groups. Most participants indicated that they would support the dissemination of the intervention by recommending it to other health departments and community-based organizations.</p> <p>Conclusions</p> <p>Findings from this exploratory study provide initial insight into factors associated with public health policy makers' intentions to adopt an LTC intervention. Implications for future research in this area, as well as potential policy-related strategies for enhancing the adoption of LTC interventions, are discussed.</p

Health risk behaviours among adolescents in the English-speaking Caribbean: a review

<p>Abstract</p> <p>Background</p> <p>The aim of this paper was to review and summarize research on prevalence of health risk behaviours, their outcomes as well as risk and protective factors among adolescents in the English-speaking Caribbean.</p> <p>Methods</p> <p>Searching of online databases and the World Wide Web as well as hand searching of the <it>West Indian Medical Journal </it>were conducted. Papers on research done on adolescents aged 10 – 19 years old and published during the period 1980 – 2005 were included.</p> <p>Results</p> <p>Ninety-five relevant papers were located. Five papers were published in the 1980s, 47 in the 1990s, and from 2000–2005, 43 papers. Health risk behaviours and outcomes were divided into seven themes. Prevalence data obtained for these, included lifetime prevalence of <b>substance use</b>: cigarettes-24% and marijuana-17%; <b>high risk sexual behaviour</b>: initiation of sexual activity ≤ 10 years old-19% and those having more than six partners-19%; <b>teenage pregnancy</b>: teens account for 15–20% of all pregnancies and one-fifth of these teens were in their second pregnancy; <b>Sexually-Transmitted Infections (STIs)</b>: population prevalence of gonorrhoea and/or chlamydia in 18–21 year-olds was 26%; <b>mental health</b>: severe depression in the adolescent age group was 9%, and attempted suicide-12%; <b>violence and juvenile delinquency</b>: carrying a weapon to school in the last 30 days-10% and almost always wanting to kill or injure someone-5%; <b>eating disorders and obesity</b>: overweight-11%, and obesity-7%. Many of the risk behaviours in adolescents were shown to be related to the adolescent's family of origin, home environment and parent-child relationships. Also, the protective effects of family and school connectedness as well as increased religiosity noted in studies from the United States were also applicable in the Caribbean.</p> <p>Conclusion</p> <p>There is a substantial body of literature on Caribbean adolescents documenting prevalence and correlates of health risk behaviours. Future research should emphasize the designing and testing of interventions to alleviate this burden.</p

Understanding Communication of Sustainability Reporting: Application of Symbolic Convergence Theory (SCT)

The purpose of this paper is to investigate the nature of rhetoric and rhetorical strategies that are implicit in the standalone sustainability reporting of the top 24 companies of the Fortune 500 Global. We adopt Bormann’s (Q J Speech 58(4):396–407, 1972) SCT framework to study the rhetorical situation and how corporate sustainability reporting (CSR) messages can be communicated to the audience (public). The SCT concepts in the sustainability reporting’s communication are subject to different types of legitimacy strategies that are used by corporations as a validity and legitimacy claim in the reports. A content analysis has been conducted and structural coding schemes have been developed based on the literature. The schemes are applied to the SCT model which recognizes the symbolic convergent processes of fantasy among communicators in a Society. The study reveals that most of the sample companies communicate fantasy type and rhetorical vision in their corporate sustainability reporting. However, the disclosure or messages are different across locations and other taxonomies of the SCT framework. This study contributes to the current CSR literature about how symbolic or fantasy understandings can be interpreted by the users. It also discusses the persuasion styles that are adopted by the companies for communication purposes. This study is the theoretical extension of the SCT. Researchers may be interested in further investigating other online communication paths, such as human rights reports and director’s reports

Developing Authentic Leadership In Novice Principals Through Leadership Coaching

The principalship today challenges the most experienced and capable of leaders. The increasingly rigorous demands of educating a diverse population for a highly competitive global world necessitates exceptional school leadership. Training novice principals before their leadership begins and continuing to support their development during their first several years has become an urgent responsibility for universities and school districts. This study employed a mixed-methods approach to explore the relationship between leadership coaching and the development of Authentic Leadership, a leadership construct that stresses the importance of leadership grounded in values and self-awareness. An online administration of the Authentic Leadership Questionnaire was administered to two groups of novice principals. One group had received leadership coaching and the other had not. Responses were examined for differences in Authentic Leadership traits between the groups. Semi-structured interviews with coaches and coachees provide a qualitative look at the impact of leadership coaching on leadership development. The research findings provide insight for districts looking to enhance their principal development programs.Educational Leadership and Policy Studies, Department o