Optimal design application on the advanced aeroelastic rotor blade

The vibration and performance optimization procedure using regression analysis was successfully applied to an advanced aeroelastic blade design study. The major advantage of this regression technique is that multiple optimizations can be performed to evaluate the effects of various objective functions and constraint functions. The data bases obtained from the rotorcraft flight simulation program C81 and Myklestad mode shape program are analytically determined as a function of each design variable. This approach has been verified for various blade radial ballast weight locations and blade planforms. This method can also be utilized to ascertain the effect of a particular cost function which is composed of several objective functions with different weighting factors for various mission requirements without any additional effort

The K Band Luminosity Functions of Galaxies in High Redshift Clusters

K band luminosity functions (LFs) of three, massive, high redshift clusters of galaxies are presented. The evolution of K*, the characteristic magnitude of the LF, is consistent with purely passive evolution, and a redshift of forma tion z = 1.5-2.Comment: 3 pages, to appear in Proceedings of IAU Colloquium 195 - Outskirts of Galaxy Clusters: intense life in the suburb

Climate resilience in the United Kingdom wine production sector: CREWS-UK

As cool climate viticulture rapidly expands, the England and Wales wine sector is winning international acclaim, particularly for its sparkling wines, and is attracting significant investment. Supported by warming climate trends during the growing season, wine producers are establishing new vineyards planted predominantly with Pinot Noir and Chardonnay. Grape-friendly weather conditions in 2018 led to a record harvest and may be a sign of good things to come. Long term (100-years) Growing Season Average Temperatures (GSTs) in south-east and south-central England have noticeably increased with 6 of the top 10 warmest growing seasons (April–October), over the last 100 years, occurring since 2005. However, weather and growing season conditions fluctuate markedly from year to year, meaning that yields and grape quality continue to vary significantly. Weather extremes are anticipated to become more frequent under future climate change, further threatening the stability of production. Current uncertainty over future climatic conditions during the growing season and their potential effects on viticulture in the UK exposes both existing producers and potential investors to unquantified risks and opportunities. The CREWS-UK climate resilience research project is generating actionable information on how climate change may affect the wine production sector, to support better decision-making and investment

Can Memoirs Be Used For Spiritual Development in a Book Group?

Biographies have historically been used by Christians for instruction and encouragement. The current trend in biographical writing is the memoir. Can spiritual memoirs be used as an effective tool for learning more about Scripture, doctrine or the Christian life? Approximately twenty spiritual memoirs were read and evaluated to determine if there was a central theme or series of themes that provided a story-based context for exploring greater biblical truths. This article reviews the genre of spiritual memoirs, discusses their strengths and weaknesses, and suggests a method for preparing them for a book group format

Undergraduate research in primary care: Is it sustainable?

To describe the research project component of the BSc in Primary Health Care and to discuss the issues faced by students and faculty in attempting to complete a student-led research project. Medical schools increasingly expect medical students to undertake research as part of intercalated BSc’s or in self-selected study modules. This research has historically been laboratory based, ‘piggybacking’ onto existing projects. Projects initiated by students themselves and studies in primary care or community settings are more unusual. A qualitative study, based on interviews with students and examiners, triangulated with data from the peer review process and personal observations on the running of the course. A London medical school, running an intercalated BSc in Primary Health Care. We interviewed 24 of 26 students and two external examiners during the interview period of the study. Students successfully undertook research, from initial question through to publication. Overall, 90 dissertations were completed since 1997, of which half used a qualitative methodology (45/90). Ten projects have subsequently been published; there were also 16 conference presentations and 6 research letters. Themes from the interview data include: the students’ strong sense of project ownership, the difficulties of being a novice researcher, the difficulties posed by the research governance hurdles, the beneficial and for some students adverse impact (stress and coping with unsuccessful projects) and finally, the impact on their careers. Students gain considerably from this learning process, not only by undertaking their own research, but they also gain in terms of acquisition of transferable skills such as critical appraisal and improved self-directedness. Project completion and publication rates suggest that programmes developing undergraduate initiated research projects can be as successful as those for other novice researchers. The student-led project is a fragile endeavour, but currently is sustainable. © 2008, Cambridge University Press. All rights reserved

Repair techniques for celion/LARC-160 graphite/polyimide composite structures

The large stiffness-to-weight and strength-to-weight ratios of graphite composite in combination with the 600 F structural capability of the polyimide matrix can reduce the total structure/TPS weight of reusable space vehicles by 20-30 percent. It is inevitable that with planned usage of GR/PI structural components, damage will occur either in the form of intrinsic flaw growth or mechanical damage. Research and development programs were initiated to develop repair processes and techniques specific to Celion/LARC-160 GR/PI structure with emphasis on highly loaded and lightly loaded compression critical structures for factory type repair. Repair processes include cocure and secondary bonding techniques applied under vacuum plus positive autoclave pressure. Viable repair designs and processes are discussed for flat laminates, honeycomb sandwich panels, and hat-stiffened skin-stringer panels. The repair methodology was verified through structural element compression tests at room temperature and 315 C (600 F)

Development of Auditory Selective Attention: Why Children Struggle to Hear in Noisy Environments

Children’s hearing deteriorates markedly in the presence of unpredictable noise. To explore why, 187 school-age children (4–11 years) and 15 adults performed a tone-in-noise detection task, in which the masking noise varied randomly between every presentation. Selective attention was evaluated by measuring the degree to which listeners were influenced by (i.e., gave weight to) each spectral region of the stimulus. Psychometric fits were also used to estimate levels of internal noise and bias. Levels of masking were found to decrease with age, becoming adult-like by 9–11 years. This change was explained by improvements in selective attention alone, with older listeners better able to ignore noise similar in frequency to the target. Consistent with this, age-related differences in masking were abolished when the noise was made more distant in frequency to the target. This work offers novel evidence that improvements in selective attention are critical for the normal development of auditory judgments

Determination of the oxidative stability of perfluoropolyalkyl ethers and correlation with chemical structure

The oxidative stabilities of several perfluoropolyalkyl ethers (PFPAE) with related chemical structures were determined by thermal gravimetric analysis and correlated with their chemical structures. These results show that oxidative stability increases as the number of difluoroformal groups decreases and as trifluoromethyl substituents are added. They are also consistent with a recently proposed intramolecular disproportionation reaction mechanism involving coordination of successive ether oxygens to a Lewis acid. Since polytetrafluoroethylene contains no oxygen, it provides an indication of the upper limit to oxidative stability of PFPAE fluids. These results also show that oxidative decomposition of PFPAE fluids requires the presence of an active metal as well as air. Consequently, it may be possible to minimize decomposition and thus improve oxidative stability by passivating reactive metal surfaces

Determination of the thermal stability of perfluoroalkylethers

The thermal decomposition temperatures of several commercial and custom synthesized perfluoroalkylether fluids were determined with a computerized tensimeter. In general, the decomposition temperatures of the commercial fluids were all similar and significantly higher than those for custom synthesized fluids. Correlation of the decomposition temperatures with the molecular structures of the primary components of the commercial fluids revealed that the stability of the fluids is not affected by intrinsic factors such as carbon chain length, branching, or cumulated difluoroformal groups. Instead, correlation with extrinsic factors revealed that the stability may be limited by the presence of small quantities of thermally unstable material and/or chlorine-containing material arising from the use of chlorine-containing solvents during synthesis. Finally, correlation of decomposition temperatures with molecular weights for Demnum and Krytox fluids supports a chain cleavage reaction mechanism for Demnum fluids and an unzipping reaction mechanism for Krytox fluids