175 research outputs found
Wind-Tunnel Investigation of the Effects of Profile Modification and Tabs on the Characteristics of Ailerons on a Low-Drag Airfoil
An investigation has been made to determine the effect of control-surface profile modifications on the aerodynamic characteristics of an NACA low-drag airfoil equipped with a 0.20-chord and a 0.15-chord aileron. Tab characteristics have been obtained for 0.20-aileron chord tabs on two of the 0.20-chord ailerons. Basic data are presented from which the effect of tabs can be calculated for specific cases. The data are sufficient for the solution of problems of fixed tabs with a differential linkage, as well as simple and spring-linked balancing tabs
Design of a differential housing and components of differential assembly
Each year the Society of Automotive Engineers (SAE) holds a competition in Pontiac,
Michigan called Formula SAE (FSAE). Each year SAE releases a revised rulebook outlining the
constraints of the upcoming year’s competition. The racecar to be designed is an open-wheeled,
mid-engine, rear-wheel drive racecar. This year’s Drexel FSAE team has approached us with a
project to design a completely symmetrical differential assembly using a Torsen differential.
This differential will be mounted to the rear of the engine, placing no stress on the rear chassis of
the racecar. This will design will allow a shorter wheelbase and narrower track, as well as
bringing the center of gravity of the racecar closer to its centerline. We intent to manufacture a
prototype differential assembly and rear chassis for testing and use on the 2005 Drexel Formula
SAE racecar
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Selecting Optimal Screening Items for Delirium: An Application of Item Response Theory
Background: Delirium (acute confusion), is a common, morbid, and costly complication of acute illness in older adults. Yet, researchers and clinicians lack short, efficient, and sensitive case identification tools for delirium. Though the Confusion Assessment Method (CAM) is the most widely used algorithm for delirium, the existing assessments that operationalize the CAM algorithm may be too long or complicated for routine clinical use. Item response theory (IRT) models help facilitate the development of short screening tools for use in clinical applications or research studies. This study utilizes IRT to identify a reduced set of optimally performing screening indicators for the four CAM features of delirium. Methods: Older adults were screened for enrollment in a large scale delirium study conducted in Boston-area post-acute facilities (n = 4,598). Trained interviewers conducted a structured delirium assessment that culminated in rating the presence or absence of four features of delirium based on the CAM. A pool of 135 indicators from established cognitive testing and delirium assessment tools were assigned by an expert panel into two indicator sets per CAM feature representing (a) direct interview questions, including cognitive testing, and (b) interviewer observations. We used IRT models to identify the best items to screen for each feature of delirium. Results: We identified 10 dimensions and chose up to five indicators per dimension. Preference was given to items with peak psychometric information in the latent trait region relevant for screening for delirium. The final set of 48 indicators, derived from 39 items, maintains fidelity to clinical constructs of delirium and maximizes psychometric information relevant for screening. Conclusions: We identified optimal indicators from a large item pool to screen for delirium. The selected indicators maintain fidelity to clinical constructs of delirium while maximizing psychometric information important for screening. This reduced item set facilitates development of short screening tools suitable for use in clinical applications or research studies. This study represents the first step in the establishment of an item bank for delirium screening with potential questions for clinical researchers to select from and tailor according to their research objectives
Signal transduction in light-oxygen-voltage receptors lacking the adduct- forming cysteine residue
Light–oxygen–voltage (LOV) receptors sense blue light through the
photochemical generation of a covalent adduct between a flavin-nucleotide
chromophore and a strictly conserved cysteine residue. Here we show that,
after cysteine removal, the circadian-clock LOV-protein Vivid still undergoes
light-induced dimerization and signalling because of flavin photoreduction to
the neutral semiquinone (NSQ). Similarly, photoreduction of the engineered LOV
histidine kinase YF1 to the NSQ modulates activity and downstream effects on
gene expression. Signal transduction in both proteins hence hinges on flavin
protonation, which is common to both the cysteinyl adduct and the NSQ. This
general mechanism is also conserved by natural cysteine-less, LOV-like
regulators that respond to chemical or photoreduction of their flavin
cofactors. As LOV proteins can react to light even when devoid of the adduct-
forming cysteine, modern LOV photoreceptors may have arisen from ancestral
redox-active flavoproteins. The ability to tune LOV reactivity through
photoreduction may have important implications for LOV mechanism and
optogenetic applications
For the Progress of “Faustus and Helen”: Crane, Whitman, and the Metropolitan Progress Poem
This essay is meant to invigorate a critical discussion of the progress poem—a genre that, while prevalent in American literature, has been virtually ignored by critics and scholars. In lieu of tackling the genre in its entirety, a project too large for just one article, the author focuses the argument through the well-known alignment between Walt Whitman and Hart Crane on the subject of the modern city. It is through the progress poem genre that Crane and Whitman’s peculiar place in metropolitan poetics can best be understood, and it is through their poetry that scholars can begin to approach the broader issue of the progress poem’s place in American literature.
Cet article vise à soulever un débat critique au sujet de la poésie du progrès, un genre courant dans la littérature étatsunienne, mais pratiquement ignoré par les critiques et les commentateurs. Plutôt que d’aborder le genre dans son entièreté – un projet qui déborde du cadre d’un article –, l’auteur resserre l’argumentation autour du parallèle bien connu entre Walt Whitman et Hart Crane concernant le traitement de la ville moderne. C’est la poésie du progrès en tant que genre qui permet le mieux de comprendre la place particulière qu’occupent ces deux auteurs dans la poésie métropolitaine, et c’est par leurs poèmes que les chercheurs peuvent aborder la question plus vaste de la place du poème sur le progrès dans la littérature étatsunienne
Transcriptional Profiling of Aging in Human Muscle Reveals a Common Aging Signature
We analyzed expression of 81 normal muscle samples from humans of varying ages, and have identified a molecular profile for aging consisting of 250 age-regulated genes. This molecular profile correlates not only with chronological age but also with a measure of physiological age. We compared the transcriptional profile of muscle aging to previous transcriptional profiles of aging in the kidney and the brain, and found a common signature for aging in these diverse human tissues. The common aging signature consists of six genetic pathways; four pathways increase expression with age (genes in the extracellular matrix, genes involved in cell growth, genes encoding factors involved in complement activation, and genes encoding components of the cytosolic ribosome), while two pathways decrease expression with age (genes involved in chloride transport and genes encoding subunits of the mitochondrial electron transport chain). We also compared transcriptional profiles of aging in humans to those of the mouse and fly, and found that the electron transport chain pathway decreases expression with age in all three organisms, suggesting that this may be a public marker for aging across species
Effects of improved home heating on asthma in community dwelling children: randomised controlled trial
Objective To assess whether non-polluting, more effective home heating (heat pump, wood pellet burner, flued gas) has a positive effect on the health of children with asthma
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