Development of improved-durability plasma sprayed ceramic coatings for gas turbine engines

As part of a NASA program to reduce fuel consumption of current commercial aircraft engines, methods were investigated for improving the durability of plasma sprayed ceramic coatings for use on vane platforms in the JT9D turbofan engine. Increased durability concepts under evaluation include use of improved strain tolerant microstructures and control of the substrate temperature during coating application. Initial burner rig tests conducted at temperatures of 1010 C (1850 F) indicate that improvements in cyclic life greater than 20:1 over previous ceramic coating systems were achieved. Three plasma sprayed coating systems applied to first stage vane platforms in the high pressure turbine were subjected to a 100-cycle JT9D engine endurance test with only minor damage occurring to the coatings

Examining cognitive, motivational and environmental factors that relate to reading performance for children with English as a first or additional language

Mixed findings exist in the literature regarding the reading skills of children with English as an Additional Language (EAL). Moreover, little research has considered how related literacy skills, motivation, and environmental factors may differ between EAL children and English monolinguals, and how these factors may contribute to reading outcomes. The present study compared 36 children with EAL and 31 monolingual English children (mean age 9 years) on measures of reading, phonology, vocabulary, motivation and environmental factors. No group differences were found in word reading and reading fluency, phonological awareness, expressive vocabulary, reading motivation, time spent reading with a parent and independently, and parental attitudes to reading. However, maternal education was lower in the EAL group and these children had more children’s books at home than their monolingual peers. The findings confirm the importance of phonological awareness and expressive vocabulary for reading performance in both groups, as well as suggesting that maternal education may indirectly relate to EAL children’s reading abilities through maternal attitudes towards reading. In contrast, in the case of monolingual children, maternal education related to number of books in the home. Implications and suggestions for future research are discussed

Experimental Investigation of Optimized Cold-formed Steel Compression Members

In the past, standard C - shaped metal studs have been the only option for designers and contractors when selecting a cross section for load bearing compression members. T he sigma shaped section has recently emerged as an alternative to the C - section. The sigma shaped section is very similar to the C - shape, with the exception of having an intermediate web return and complex stiffeners. The experimental results of concentric axial compression tests of fifty - eight sigma shaped members are reported. Specimen s were tested at various lengths to force global, distortional, and local buckling failure modes. Additionally, the test program contained members with and without web holes. Comparisons of experimental results with the American Iron and Steel Institute ( AISI) design methods, Effective Width Method (EWM) and Direct Strength Method (DSM), are discussed

The Fenian Narrative Corpus, c.600–c.2000: A Reassessment

This dissertation traces the historical development of the Fenian narrative tradition—i.e. the vast body of story and song, some of it well over a millennium old, about the Gaelic hero, Fionn Mac Cumhaill and his roving warrior band. The first chapter traces the history of the tradition from the early medieval period up to Macpherson’s monumental publications. The nature of the literary manifestations of Fenian topics and such evidence as there is for an oral tradition prior to modern attestations are discussed. In a demonstration of the cultural relevance of the tradition, the ways in which socially and politically relevant meanings may have been woven into the extant texts are also explored. The focus then shifts in the second chapter to a consideration of the approaches taken to Fenian literature and lore in the Macphersonic period. Macpherson’s cultural milieu, motivations, and creative process are investigated, and his adaptations are situated in their national and international contexts. Their influence and sociopolitical import within a trans-Gaelic sphere in the century after their publication are then addressed. The third and final chapter examines the Fenian tradition in the post-Macphersonic period, with a particular focus on the sociopolitical significance of modern approaches to the Fenian tradition. This is the period of folklore collection, and of primary importance are the motivations and activities of folklore collectors in the Gaelic regions. Also explored are modern publications, adaptations, and overt politicizations of Fenian material, particularly in Ireland. The image of the Fenian tradition that emerges from this tripartite consideration is one of a dynamic and multifaceted body of story and song that has remained relevant over the centuries due to constant adaptation.Celtic Languages and Literature

Flow dynamics and mixing processes in hydraulic jump arrays: Implications for channel-lobe transition zones

A detailed field investigation of a saline gravity current in the southwest Black Sea has enabled the first complete analysis of three-dimensional flow structure and dynamics of a series of linked hydraulic jumps in stratified, density-driven, flows. These field observations were collected using an acoustic Doppler current profiler mounted on an autonomous underwater vehicle, and reveal that internal mixing processes in hydraulic jumps, including flow expansion and recirculation, provide a previously unrecognised mechanism for grain-size sorting and segregation in stratified density-driven flows. Field observations suggest a newly identified type of hydraulic jump, that is a stratified low Froude number (< 1.5–2) subaqueous hydraulic jump, with an enhanced ability to transport sediment downstream of the jump, in comparison to hydraulic jumps in other subaerial and submarine flows. These novel field data underpin a new process-based conceptual model of channel lobe transition zones (CLTZs) that explains the scattered offset nature of scours within such settings, the temporal variations in infill and erosion between adjacent scours, how bed shear stresses are maintained across the CLTZ, and why the locus of deposition is so far downstream of the scour zone

A molecular concept of caste in insect societies

The term ‘caste’ is used to describe the division of reproductive labour that defines eusocial insect societies. The definition of ‘caste’ has been debated over the last 50 years, specifically with respect to the simplest insect societies; this raises the question of whether a simple categorisation of social behaviour by reproductive state alone is helpful. Gene-level analyses of behaviours of individuals in hymenopteran social insect societies now provide a new empirical base-line for defining caste and understanding the evolution and maintenance of a reproductive division of labour. We review this literature to identify a set of potential molecular signatures that, combined with behavioural, morphological and physiological data, help define caste more precisely; these signatures vary with the type of society, and are likely to be influenced by ecology, life-history, and stage in the colony cycle. We conclude that genomic approaches provide us with additional ways to help quantify and categorise caste, and behaviour in general

Racial differences between African-American and white women in insulin resistance and visceral adiposity are associated with differences in apoCIII containing apoAI and apoB lipoproteins

Background: African-Americans have higher HDL, less visceral adipose tissue (VAT) and lower triglyceride (TG) and apoCIII concentrations than whites, despite being more insulin-resistant. We studied in African-American and white women the influences of insulin resistance and VAT on the apoAI concentrations of two HDL subspecies, one that contains apoCIII that is associated with increased risk of coronary heart disease (CHD) and one that does not have apoCIII that is associated with decreased CHD; and on the apoCIII concentrations of HDL and of the apoB lipoproteins. Methods: The participants were 32 women (14 African-Americans, 18 white) of similar age (39 ± 12 vs. 42 ± 11y). Mean BMI was 34 kg/m2 in the African-Americans compared to 30 in the whites. A standard diet (33% fat, 52% carbohydrate, 15% protein) was provided for 7 days followed by a test meal (40% fat, 40% carbohydrate, 20% protein) on Day 8. Insulin sensitivity index (SI) was calculated from the minimal model. Results: After controlling for SI, African-Americans have a higher mean apoAI level in HDL with apoCIII compared with whites (12.9 ± 2.8 and 10.9 ± 2.9 mg/dL, respectively, P = 0.05). SI was associated with higher apoAI in HDL with apoCIII, whereas VAT was not associated with this HDL subspecies. This pattern of results was reversed for apoCIII concentrations in apoB lipoproteins. After adjusting for SI, African-Americans had lower apoCIII in apoB lipoproteins. SI was associated with lower apoCIII in total apoB lipoproteins, whereas VAT was associated with higher apoCIII in all the apoB lipoproteins. Additional adjustment for VAT tended to reduce the difference in apoCIII between the groups. Conclusions: African-American women have a higher HDL with apoCIII level than whites when controlled for insulin sensitivity. African-Americans have lower insulin sensitivity. Insulin sensitivity is associated with higher levels of HDL with apoCIII. ApoCIII levels in VLDL are lower in African-American women than whites, also affected by insulin sensitivity which is associated with low apoCIII in VLDL. VAT has a strong association with apoCIII in apoB lipoproteins but not with apoAI in HDL with apoCIII. Trial registration ClinicalTrials.gov Identifier: NCT0048486

Collimation and asymmetry of the hot blast wave from the recurrent nova V745 Scorpii

The recurrent symbiotic nova V745 Sco exploded on 2014 February 6 and was observed on February 22 and 23 by the Chandra X-ray Observatory Transmission Grating Spectrometers. By that time the supersoft source phase had already ended and Chandra spectra are consistent with emission from a hot, shock-heated circumstellar medium with temperatures exceeding 10^7K. X-ray line profiles are more sharply peaked than expected for a spherically-symmetric blast wave, with a full width at zero intensity of approximately 2400 km/s, a full width at half maximum of 1200 +/- 30 km/s and an average net blueshift of 165 +/- 10 km/s. The red wings of lines are increasingly absorbed toward longer wavelengths by material within the remnant. We conclude that the blast wave was sculpted by an aspherical circumstellar medium in which an equatorial density enhancement plays a role, as in earlier symbiotic nova explosions. Expansion of the dominant X-ray emitting material is aligned close to the plane of the sky and most consistent with an orbit seen close to face-on. Comparison of an analytical blast wave model with the X-ray spectra, Swift observations and near-infrared line widths indicates the explosion energy was approximately 10^43 erg, and confirms an ejected mass of approximately 10^-7 Msun. The total mass lost is an order of magnitude lower than the accreted mass required to have initiated the explosion, indicating the white dwarf is gaining mass and is a supernova Type 1a progenitor candidate.Comment: To appear in the Astrophysical Journa

Are harvest forecasts news? USDA announcements and futures market reactions

Futures market price data for maize and soyabeans are used to examine reactions to US Department of Agriculture harvest forecasts. These forecasts are widely known and reasonably accurate, so failure to find significant reaction would indicate that the USDA did not contribute additional news relative to information already possessed by traders. Various t-tests, f-tests, and nonparametric chi-square tests indicate rejection of the null hypothesis of no significant difference between means of absolute values or variances of changes in closing prices on days following a USDA announcement and other days. Thus, the data indicate that significant information is contained in the forecast

The algebra of the general Markov model on phylogenetic trees and networks

It is known that the Kimura 3ST model of sequence evolution on phylogenetic trees can be extended quite naturally to arbitrary split systems. However, this extension relies heavily on mathematical peculiarities of the K3ST model, and providing an analogous augmentation of the general Markov model has thus far been elusive. In this paper we rectify this shortcoming by showing how to extend the general Markov model on trees to to include arbitrary splits; and even further to more general network models. This is achieved by exploring the algebra of the generators of the continuous-time Markov chain together with the "splitting" operator that generates the branching process on phylogenetic trees. For simplicity we proceed by discussing the two state case and note that our results are easily extended to more states with little complication. Intriguingly, upon restriction of the two state general Markov model to the parameter space of the binary symmetric model, our extension is indistinguishable from the previous approach only on trees; as soon as any incompatible splits are introduced the two approaches give rise to differing probability distributions with disparate structure. Through exploration of a simple example, we give a tentative argument that our approach to extending to more general networks has desirable properties that the previous approaches do not share. In particular, our construction allows for the possibility of convergent evolution of previously divergent lineages; a property that is of significant interest for biological applications.Comment: 17 pages, 5 figure