302 research outputs found
Quiet Clean Short-haul Experimental Engine (QCSEE) under-the-wing engine composite fan blade design report
A total of 38 quiet clean short haul experimental engine under the wing composite fan blades were manufactured for various component tests, process and tooling, checkout, and use in the QCSEE UTW engine. The component tests included frequency characterization, strain distribution, bench fatigue, platform static load, whirligig high cycle fatigue, whirligig low cycle fatigue, whirligig strain distribution, and whirligig over-speed. All tests were successfully completed. All blades planned for use in the engine were subjected to and passed a whirligig proof spin test
Impact absorbing blade mounts for variable pitch blades
A variable pitch blade and blade mount are reported that are suitable for propellers, fans and the like and which have improved impact resistance. Composite fan blades and blade mounting arrangements permit the blades to pivot relative to a turbine hub about an axis generally parallel to the centerline of the engine upon impact of a large foreign object, such as a bird. Centrifugal force recovery becomes the principal energy absorbing mechanism and a blade having improved impact strength is obtained
Program for impact testing of spar-shell fan blades, test report
Six filament-wound, composite spar-shell fan blades were impact tested in a whirligig relative to foreign object damage resulting from ingestion of birds into the fan blades of a QCSEE-type engine. Four of the blades were tested by injecting a simulated two pound bird into the path of the rotating blade and two were tested by injecting a starling into the path of the blade
First beam test of Laser Engineered Surface Structures (LESS) at cryogenic temperature in CERN SPS accelerator
Electron cloud mitigation is an essential requirement for accelerators of positive particles with high intensity beams to guarantee beam stability and limited heat load in cryogenic systems. Laser Engineered Surface Structures (LESS) are being considered, within the High Luminosity upgrade of the LHC collider at CERN (HL-LHC), as an option to reduce the Secondary Electron Yield (SEY) of the surfaces facing the beam, thus suppressing the elec-tron cloud phenomenon. As part of this study, a 2.2 m long Beam Screen (BS) with LESS has been tested at cryogenic temperature in the COLD bore EXperiment (COLDEX) facility in the SPS accelerator at CERN. In this paper, we describe the manufacturing procedure of the beam screen, the employed laser treatment technique and discuss our first observations in COLDEX confirming electron cloud suppression.Electron cloud mitigation is an essential requirement for accelerators of positive particles with high intensity beams to guarantee beam stability and limited heat load in cryogenic systems. Laser Engineered Surface Structures (LESS) are being considered, within the High Luminosity upgrade of the LHC collider at CERN (HL-LHC), as an option to reduce the Secondary Electron Yield (SEY) of the surfaces facing the beam, thus suppressing the electron cloud phenomenon. As part of this study, a 2.2 m long Beam Screen (BS) with LESS has been tested at cryogenic temperature in the COLD bore EXperiment (COLDEX) facility in the SPS accelerator at CERN. In this paper, we describe the manufacturing procedure of the beam screen, the employed laser treatment technique and discuss our first observations in COLDEX confirming electron cloud suppression
The Rubber Hand Illusion: Two's a company, but three's a crowd
On the one hand, it is often assumed that the Rubber Hand Illusion (RHI) is constrained by a structural body model so that one cannot implement supernumerary limbs. On the other hand, several recent studies reported illusory duplication of the right hand in subjects exposed to two adjacent rubber hands. The present study tested whether spatial constraints may affect the possibility of inducing the sense of ownership to two rubber hands located side by side to the left of the subject's hand. We found that only the closest rubber hand appeared both objectively (proprioceptive drift) and subjectively (ownership rating) embodied. Crucially, synchronous touch of a second, but farther, rubber hand disrupted the objective measure of the RHI, but not the subjective one. We concluded that, in order to elicit a genuine RHI for multiple rubber hands, the two rubber hands must be at the same distance from the subject's hand/body
Structures performance, benefit, cost-study
New technology concepts and structural analysis development needs which could lead to improved life cycle cost for future high-bypass turbofans were studied. The NASA-GE energy efficient engine technology is used as a base to assess the concept benefits. Recommended programs are identified for attaining these generic structural and other beneficial technologies
A condição da docência universitária no contexto atual das universidades: marcas históricas, realidade e perspectivas
O artigo tem como objetivo refletir sobre alguns aspectos teóricos acerca da condição da docência e dos docentes universitários, seus saberes, seu trabalho e as relações construídas historicamente com esse fazer. Apresentamos um percurso da consolidação do ideário da universidade pública brasileira e os desdobramentos na costura da docência universitária como condição diferenciada para se realizar o trabalho, entendido por nós como sendo o ambiente de desenvolver-se profissionalmente, ao mesmo tempo em que é o lócus provocador de mudança da própria universidade, da própria condição docente e de sua relação com a sociedade. O projeto inacabado de universidade pública brasileira está sujeito, mais uma vez, ao enfrentamento da lógica do neoliberalismo, de aligeirar-se, despir-se de tempo para conhecimento, para produção, para qualidade do fazer pedagógico, na medida que sua pouca autonomia conquistada começa a ser retirada através do falso discurso da não ou da baixa produtividade a serviço do mercado e das demandas do capital não atendidas. O impacto dessas ameaças está diretamente ligado à conformação que a docência assume e submete-se para tentar sobreviver. Professores cansados, desanimados, produzindo, muitas vezes, trabalhos com qualidade duvidosa e submetendo-se às péssimas condições de trabalho, salários que não correspondem com a condição e exigência da profissão, ou, ainda, editais que nem sempre aportam recursos que validem um montante significativo de financiamento para pesquisa e ou para o aumento no número de pesquisadores, põem a mostra da realidade atual, que carece de mudanças conceituais sobre o que é a universidade e de suas condições para construir a docência universitária.
 
The identification of tyrosine as a common key residue in unrelated H-2Kd restricted antigenic peptides
we have compared the activity of several Kd-or Ld-restricted antigenic peptides as competitors in a functional competition assay using cytolytic T lymphocyte (CTL) clones. All of four unrelated Kd-restricted peptides tested could compete with each other but not with the Ld-restricted peptide P91A-.12-24 (P91A). Moreover, the P91A peptide falled to compete with the four Kd-restricted peptides. In contrast, another Ld-restricted peptide[mouse cytomegalovirus (MCMV) pp89 167-176] could clearly compete with both Kd- and Ld-restricted peptides. The comparison of a series of modified MCMV pp89 peptides suggested that distinct structural features allow the Interaction of the peptide with the two different MHC class I molecules. We showed previously that the competitor activity of two different Kd-restricted antigenic peptides was reduced substantially upon Ala substitution of the single Tyr residues present in these peptides. We now show a similar effect for two additional Kd-restricted peptides. Our results thus suggest that Tyr may function as an ‘anchor' residue for many antigentic peptides that bind to the Kdmolecule. Molecular modeling of the presumed antigen-binding site of the Kdmolecule revealed the presence of two deep cavities that may be involved in binding peptide amino acid side chains. A model Illustrating one possible interaction of a Tyr-containing peptide with the Kdmolecule is presente
Age-specific prevalence of the different clinical presentations of AD and FTD in young-onset dementia
Background Studies have shown that the prevalence of all-variants Alzheimer's disease (AD) and frontotemporal dementia (FTD) both increase with age, even before the age of 65. However, it is not known whether their different clinical presentations all increase in prevalence with age in the same way.Methods We studied the prevalence of the different clinical presentations of young-onset AD and FTD by 5-year age groups in a population-based study identifying all dementia patients with a diagnosis of AD and FTD and symptoms onset before age 65 in the Modena province, Italy. By using regression models of cumulative occurrences, we also estimated age-specific prevalence and compared the growth curves of the clinical presentations.Results The prevalence of all-variants AD increased with age, from 18/1,000,000 in the 40-44 age group to 1411/1,000,000 in the 60-64 age group. The prevalence of all-variants FTD also increased with age, from 18/1,000,000 to 866/1,000,000. An estimation of age-specific prevalence functions of each clinical presentation showed that atypical non-amnestic AD and aphasic FTD grew the most in early ages, followed by the behavioural variant of FTD (bvFTD). Then, around the age of 60, amnestic AD took over and its age-specific prevalence continued to increase disproportionally compared to all the other clinical variants of AD and FTD, which, instead, started to decrease in prevalence.Conclusions Amnestic AD is the clinical presentation that increases the most with advancing age, followed by bvFTD, suggesting that there is a differential vulnerability to the effect of ageing within the same neurodegenerative disease
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