21,950 research outputs found
Rocket nozzle test method Patent
Method for testing rocket nozzles at high tensile stress level
Stress-testing of the throat of a rocket's nozzle
Test motor in which high initial pressure can be reduced suddenly provides a method of testing stress effects in the throat of a rockets nozzle. Motors operating pressure is increased to aggravate tensile stresses in a submerged throat. Opposing compression stresses are limited by control of the operating pressure
Thematic relations affect similarity via commonalities
Thematic relations are an important source of perceived similarity. For instance, the rowing theme of boats and oars increases their perceived similarity. The mechanism of this effect, however, has not been specified previously. We investigated whether thematic relations affect similarity by increasing commonalities or by decreasing differences. In Experiment 1, thematic relations affected similarity more than difference, thereby producing a non-inversion of similarity and difference. Experiment 2 revealed substantial individual variability in the preference for thematic relations and, consequently in the non-inversion of ratings. In sum, the experiments demonstrated a non-inversion of similarity and difference that was caused by thematic relations and exhibited primarily by a subgroup of participants. These results indicate that thematic relations affect perceived similarity by increasing the contribution of commonalities rather than by decreasing the contribution of differences
Automatic vigilance for negative words in lexical decision and naming : comment on Larsen, Mercer, and Balota (2006)
An automatic vigilance hypothesis states that humans preferentially attend to negative stimuli, and this attention to negative valence disrupts the processing of other stimulus properties. Thus, negative words typically elicit slower color naming, word naming, and lexical decisions than neutral or positive words. Larsen, Mercer, and Balota (see record 2006-04603-006) analyzed the stimuli from 32 published studies, and they found that word valence was confounded with several lexical factors known to affect word recognition. Indeed, with these lexical factors covaried out, Larsen et al. found no evidence of automatic vigilance. The authors report a more sensitive analysis of 1011 words. Results revealed a small but reliable valence effect, such that negative words (e.g., "shark") elicit slower lexical decisions and naming than positive words (e.g., "beach"). Moreover, the relation between valence and recognition was categorical rather than linear; the extremity of a word's valence did not affect its recognition. This valence effect was not attributable to word length, frequency, orthographic neighborhood size, contextual diversity, first phoneme, or arousal. Thus, the present analysis provides the most powerful demonstration of automatic vigilance to date
Automatic vigilance for negative words is categorical and general
With other factors controlled, negative words elicit slower lexical decisions and naming than positive words (Estes & Adelman, 2008; see record 2008-09984-001). Moreover, this marked difference in responding to negative words and to positive words (i.e., between-category discontinuity) was accompanied by relatively uniform responding among negative words (i.e., within-category equivalence), thus suggesting a categorical model of automatic vigilance. Larsen, Mercer, Balota, and Strube (this issue; see record 2008-09984-002) corroborated our observation that valence predicts lexical decision and word naming latencies. However, on the basis of an interaction between linear arousal and linear valence, they claim that automatic vigilance does not occur among arousing stimuli and they purport to reject the categorical model. Here we show that (a) this interaction is logically irrelevant to whether automatic vigilance is categorical; (b) the linear interaction is statistically consistent with the categorical model; (c) the interaction is not observed within the categorical model; and (d) despite having 5 fewer parameters, the categorical model predicts word recognition times as well as the interaction model. Thus, automatic vigilance is categorical and generalizes across levels of arousa
Investigation of plasma contactors for use with orbiting wires
The results of a number of orbital simulations for a 300km orbital height and 28 degrees orbital inclination are included to emphasize the importance of the choice of the timing of the experiments. The bulk of the effort has gone into trying to determine the shape, size, and other optical properties of the plasma clouds that will be emitted by the hollow cathodes
Integrative priming occurs rapidly and uncontrollably during lexical processing
Lexical priming, whereby a prime word facilitates recognition of a related target word (e.g., nurse ? doctor), is typically attributed to association strength, semantic similarity, or compound familiarity. Here, the authors demonstrate a novel type of lexical priming that occurs among unassociated, dissimilar, and unfamiliar concepts (e.g., horse ? doctor). Specifically, integrative priming occurs when a prime word can be easily integrated with a target word to create a unitary representation. Across several manipulations of timing (stimulus onset asynchrony) and list context (relatedness proportion), lexical decisions for the target word were facilitated when it could be integrated with the prime word. Moreover, integrative priming was dissociated from both associative priming and semantic priming but was comparable in terms of both prevalence (across participants) and magnitude (within participants). This observation of integrative priming challenges present models of lexical priming, such as spreading activation, distributed representation, expectancy, episodic retrieval, and compound cue models. The authors suggest that integrative priming may be explained by a role activation model of relational integration
Finite temperature holographic duals of 2-dimensional BCFTs
We consider holographic duals of -dimensional conformal field theories in
the presence of a boundary, interface, defect and/or junction, referred to
collectively as BCFTs. In general, the presence of a boundary reduces the
conformal symmetry to and the dual geometry is realized as
a warped product of the form , where is not
compact. In particular, it will contain points where the warp factor of the
space diverges, leading to asymptotically regions. We show that
the space-time may always be replaced with an -"black-hole"
space-time. We argue the resulting geometry describes the BCFT at finite
temperature. To motivate this claim, we compute the entanglement entropy
holographically for a segment centered around the defect or ending on the
boundary and find agreement with a known universal formula.Comment: 16 pages, 2 figures; minor corrections and references adde
Holographic two-point functions for Janus interfaces in the CFT
This paper investigates scalar perturbations in the top-down supersymmetric
Janus solutions dual to conformal interfaces in the CFT, finding
analytic closed-form solutions. We obtain an explicit representation of the
bulk-to-bulk propagator and extract the two-point correlation function of the
dual operator with itself, whose form is not fixed by symmetry alone. We give
an expression involving the sum of conformal blocks associated with the
bulk-defect operator product expansion and briefly discuss finite-temperature
extensions. To our knowledge, this is the first two-point function computation
for a fully-backreacted, top-down holographic defect.Comment: 30 pages, PDFLaTe
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