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Sample records for left-edge prosodic boundaries

Brain response to prosodic boundary cues depends on boundary position

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Julia eHolzgrefe

2013-07-01

Full Text Available Prosodic information is crucial for spoken language comprehension and especially for syntactic parsing, because prosodic cues guide the hearer’s syntactic analysis. The time course and mechanisms of this interplay of prosody and syntax are not yet well understood. In particular, there is an ongoing debate whether local prosodic cues are taken into account automatically or whether they are processed in relation to the global prosodic context in which they appear. The present study explores whether the perception of a prosodic boundary is affected by its position within an utterance. In an event-related potential (ERP study we tested if the brain response evoked by the prosodic boundary differs when the boundary occurs early in a list of three names connected by conjunctions (i.e., after the first name as compared to later in the utterance (i.e., after the second name. A closure positive shift (CPS — marking the processing of a prosodic phrase boundary — was elicited only for stimuli with a late boundary, but not for stimuli with an early boundary. This result is further evidence for an immediate integration of prosodic information into the parsing of an utterance. In addition, it shows that the processing of prosodic boundary cues depends on the previously processed information from the preceding prosodic context.
Prosodic boundaries in writing: Evidence from a keystroke analysis

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Susanne Fuchs

2016-11-01

Full Text Available The aim of the paper is to investigate duration between successive keystrokes during typing in order to examine whether prosodic boundaries are expressed in the process of writing. In particular, we are interested in interkey durations that occur next to punctuation marks (comma and full stops while taking keystrokes between words as a reference, since these punctuation marks are often realized with minor or major prosodic boundaries during reading. A two-part experiment was conducted: first, participants’ keystrokes on a computer keyboard were recorded while writing an email to a close friend (in two conditions: with and without time pressure. Second, participants read the email they just wrote. Interkey durations were compared to pause durations at the same locations during read speech. Results provide evidence of significant differences between interkey durations between words, at commas and at full stops (from shortest to longest. These durations were positively correlated with silent pause durations during reading. A more detailed analysis of interkey durations revealed patterns that can be interpreted with respect to prosodic boundaries in speech production, namely as phrase-final and phrase-initial lengthening occurring at punctuation marks. This work provides initial evidence that prosodic boundaries are reflected in the writing process.
Prosodic Boundaries in Writing: Evidence from a Keystroke Analysis.

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Fuchs, Susanne; Krivokapić, Jelena

2016-01-01

The aim of the paper is to investigate duration between successive keystrokes during typing in order to examine whether prosodic boundaries are expressed in the process of writing. In particular, we are interested in interkey durations that occur next to punctuation marks (comma and full stops while taking keystrokes between words as a reference), since these punctuation marks are often realized with minor or major prosodic boundaries during overt reading. A two-part experiment was conducted: first, participants' keystrokes on a computer keyboard were recorded while writing an email to a close friend (in two conditions: with and without time pressure). Second, participants read the email they just wrote. Interkey durations were compared to pause durations at the same locations during read speech. Results provide evidence of significant differences between interkey durations between words, at commas and at full stops (from shortest to longest). These durations were positively correlated with silent pause durations during overt reading. A more detailed analysis of interkey durations revealed patterns that can be interpreted with respect to prosodic boundaries in speech production, namely as phrase-final and phrase-initial lengthening occurring at punctuation marks. This work provides initial evidence that prosodic boundaries are reflected in the writing process.
Prosodic Marking of Narrow Focus in Seoul Korean

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Hae-Sung Jeon

2017-01-01

Full Text Available This paper explores prosodic marking of narrow (corrective focus in Seoul Korean. Korean lacks lexical stress and it has a phonologized association between the Accentual Phrase (AP initial segment and intonation. In the experiment, 4 speakers read sentences including a two-item list which were designed to elicit either an L or H AP-initial tone. The durational variations, the pitch events at prosodic boundaries, and 'F''0 'span in 32 sentences read neutrally and 64 sentences read with one of the items under focus were analyzed. The results show that the focused constituent consistently initiates a new prosodic phrase. In comparison to the neutrally spoken or defocused counterpart, the focused constituent was more likely to be realized as an Intonational Phrase (IP in some contexts. Bitonal IP boundary tones were more likely to occur under focus than monotonal tones. In addition, in focused constituents, durational expansion particularly at the phrase-edges, expansion in 'F''0 'span, and raising of the phrase-initial pitch were observed. On the other hand, defocused constituents were not phonetically reduced compared to the neutral counterparts. The results imply that the phonetic cues spreading over the focused constituent complement the exaggerated prosodic boundaries.
The nature of hemispheric specialization for linguistic and emotional prosodic perception: a meta-analysis of the lesion literature.

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Witteman, Jurriaan; van Ijzendoorn, Marinus H; van de Velde, Daan; van Heuven, Vincent J J P; Schiller, Niels O

2011-11-01

It is unclear whether there is hemispheric specialization for prosodic perception and, if so, what the nature of this hemispheric asymmetry is. Using the lesion-approach, many studies have attempted to test whether there is hemispheric specialization for emotional and linguistic prosodic perception by examining the impact of left vs. right hemispheric damage on prosodic perception task performance. However, so far no consensus has been reached. In an attempt to find a consistent pattern of lateralization for prosodic perception, a meta-analysis was performed on 38 lesion studies (including 450 left hemisphere damaged patients, 534 right hemisphere damaged patients and 491 controls) of prosodic perception. It was found that both left and right hemispheric damage compromise emotional and linguistic prosodic perception task performance. Furthermore, right hemispheric damage degraded emotional prosodic perception more than left hemispheric damage (trimmed g=-0.37, 95% CI [-0.66; -0.09], N=620 patients). It is concluded that prosodic perception is under bihemispheric control with relative specialization of the right hemisphere for emotional prosodic perception. Copyright Â© 2011 Elsevier Ltd. All rights reserved.
Interactivity in prosodic representations in children.

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Goffman, Lisa; Westover, Stefanie

2013-11-01

The aim of this study was to determine, using speech error and articulatory analyses, whether the binary distinction between iambs and trochees should be extended to include additional prosodic subcategories. Adults, children who are normally developing, and children with specific language impairment (SLI) participated. Children with SLI were included because they exhibit prosodic and motor deficits. Children, especially those with SLI, showed the expected increase in omission errors in weak initial syllables. Movement patterning analyses revealed that speakers produced differentiated articulatory templates beyond the broad categories of iamb and trochee. Finally, weak-weak prosodic sequences that crossed word boundaries showed increased articulatory variability when compared with strong-weak alternations. The binary distinction between iamb and trochee may be insufficient, with additional systematic prosodic subcategories evident, even in young children with SLI. Findings support increased interactivity in language processing.
Effects of gender and regional dialect on prosodic patterns in American English

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Clopper, Cynthia G.; Smiljanic, Rajka

2011-01-01

While cross-dialect prosodic variation has been well established for many languages, most variationist research on regional dialects of American English has focused on the vowel system. The current study was designed to explore prosodic variation in read speech in two regional varieties of American English: Southern and Midland. Prosodic dialect variation was analyzed in two domains: speaking rate and the phonetic expression of pitch movements associated with accented and phrase-final syllables. The results revealed significant effects of regional dialect on the distributions of pauses, pitch accents, and phrasal-boundary tone combinations. Significant effects of talker gender were also observed on the distributions of pitch accents and phrasal-boundary tone combinations. The findings from this study demonstrate that regional and gender identity features are encoded in part through prosody, and provide further motivation for the close examination of prosodic patterns across regional and social varieties of American English. PMID:21686317
Phrase Lengths and the Perceived Informativeness of Prosodic Cues in Turkish.

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Dinçtopal Deniz, Nazik; Fodor, Janet Dean

2017-12-01

It is known from previous studies that in many cases (though not all) the prosodic properties of a spoken utterance reflect aspects of its syntactic structure, and also that in many cases (though not all) listeners can benefit from these prosodic cues. A novel contribution to this literature is the Rational Speaker Hypothesis (RSH), proposed by Clifton, Carlson and Frazier. The RSH maintains that listeners are sensitive to possible reasons for why a speaker might introduce a prosodic break: "listeners treat a prosodic boundary as more informative about the syntax when it flanks short constituents than when it flanks longer constituents," because in the latter case the speaker might have been motivated solely by consideration of optimal phrase lengths. This would effectively reduce the cue value of an appropriately placed prosodic boundary. We present additional evidence for the RSH from Turkish, a language typologically different from English. In addition, our study shows for the first time that the RSH also applies to a prosodic break which conflicts with the syntactic structure, reducing its perceived cue strength if it might have been motivated by length considerations. In this case, the RSH effect is beneficial. Finally, the Turkish data show that prosody-based explanations for parsing preferences such as the RSH do not take the place of traditional syntax-sensitive parsing strategies such as Late Closure. The two sources of guidance co-exist; both are used when available.
An influence of extremal edges on boundary extension.

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Hale, Ralph G; Brown, James M; McDunn, Benjamin A; Siddiqui, Aisha P

2015-08-01

Studies have shown that people consistently remember seeing more of a studied scene than was physically present (e.g., Intraub & Richardson Journal of Experimental Psychology: Learning, Memory, and Cognition, 15, 179-187, 1989). This scene memory error, known as boundary extension, has been suggested to occur due to an observer's failure to differentiate between the contributing sources of information, including the sensory input, amodal continuation beyond the view boundaries, and contextual associations with the main objects and depicted scene locations (Intraub, 2010). Here, "scenes" made of abstract shapes on random-dot backgrounds, previously shown to elicit boundary extension (McDunn, Siddiqui, & Brown Psychonomic Bulletin & Review, 21, 370-375, 2014), were compared with versions made with extremal edges (Palmer & Ghose Psychological Science, 19, 77-84, 2008) added to their borders, in order to examine how boundary extension is influenced when amodal continuation at the borders' view boundaries is manipulated in this way. Extremal edges were expected to reduce boundary extension as compared to the same scenes without them, because extremal edge boundaries explicitly indicate an image's end (i.e., they do not continue past the view boundary). A large and a small difference (16 % and 40 %) between the close and wide-angle views shown during the experiment were tested to examine the effects of both boundary extension and normalization with and without extremal edges. Images without extremal edges elicited typical boundary extension for the 16 % size change condition, whereas the 40 % condition showed signs of normalization. With extremal edges, a reduced amount of boundary extension occurred for the 16 % condition, and only normalization was found for the 40 % condition. Our findings support and highlight the importance of amodal continuation at the view boundaries as a component of boundary extension.
Predicting prosodic structure by morphosyntactic category: A case study of Blackfoot

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Joseph W. Windsor

2017-02-01

Full Text Available This study examines phonetic correlates to three prosodic categories in Blackfoot: the syllable (σ, the prosodic word (ω, and the phonological phrase (φ. I provide evidence that the Blackfoot σ is recognizable by an obligatory process of vowel coalescence and the φ is recognizable by an obligatory process of right edge aspiration. The ω can be distinguished from these other two prosodic constituents by an optional phonetic process which mimics intersyllabic vowel coalescence, but does not apply obligatorily. The prosodic categories investigated in this study are then correlated to three morphosyntactic categories: morphological agreement suffixes, lexical morphemes (adjectives and nouns, and demonstratives. This correlation is used to argue that morphological and syntactic processes function differently at the interface with phonology (cf. Russell 1999, ultimately raising questions with “word-internal syntax” analyses of Blackfoot suffixation which are derived through cyclic head movement (Bliss 2013; Wiltschko 2014 using the Mirror Principle (Baker 1985. This article is part of theSpecial Collection: Prosody and costituent structure
Word segmentation with universal prosodic cues.

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Endress, Ansgar D; Hauser, Marc D

2010-09-01

When listening to speech from one's native language, words seem to be well separated from one another, like beads on a string. When listening to a foreign language, in contrast, words seem almost impossible to extract, as if there was only one bead on the same string. This contrast reveals that there are language-specific cues to segmentation. The puzzle, however, is that infants must be endowed with a language-independent mechanism for segmentation, as they ultimately solve the segmentation problem for any native language. Here, we approach the acquisition problem by asking whether there are language-independent cues to segmentation that might be available to even adult learners who have already acquired a native language. We show that adult learners recognize words in connected speech when only prosodic cues to word-boundaries are given from languages unfamiliar to the participants. In both artificial and natural speech, adult English speakers, with no prior exposure to the test languages, readily recognized words in natural languages with critically different prosodic patterns, including French, Turkish and Hungarian. We suggest that, even though languages differ in their sound structures, they carry universal prosodic characteristics. Further, these language-invariant prosodic cues provide a universally accessible mechanism for finding words in connected speech. These cues may enable infants to start acquiring words in any language even before they are fine-tuned to the sound structure of their native language. Copyright © 2010. Published by Elsevier Inc.
The integration of prosodic speech in high functioning autism: a preliminary FMRI study.

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Isabelle Hesling

2010-07-01

Full Text Available Autism is a neurodevelopmental disorder characterized by a specific triad of symptoms such as abnormalities in social interaction, abnormalities in communication and restricted activities and interests. While verbal autistic subjects may present a correct mastery of the formal aspects of speech, they have difficulties in prosody (music of speech, leading to communication disorders. Few behavioural studies have revealed a prosodic impairment in children with autism, and among the few fMRI studies aiming at assessing the neural network involved in language, none has specifically studied prosodic speech. The aim of the present study was to characterize specific prosodic components such as linguistic prosody (intonation, rhythm and emphasis and emotional prosody and to correlate them with the neural network underlying them.We used a behavioural test (Profiling Elements of the Prosodic System, PEPS and fMRI to characterize prosodic deficits and investigate the neural network underlying prosodic processing. Results revealed the existence of a link between perceptive and productive prosodic deficits for some prosodic components (rhythm, emphasis and affect in HFA and also revealed that the neural network involved in prosodic speech perception exhibits abnormal activation in the left SMG as compared to controls (activation positively correlated with intonation and emphasis and an absence of deactivation patterns in regions involved in the default mode.These prosodic impairments could not only result from activation patterns abnormalities but also from an inability to adequately use the strategy of the default network inhibition, both mechanisms that have to be considered for decreasing task performance in High Functioning Autism.
A Kinematic Study of Prosodic Structure in Articulatory and Manual Gestures: Results from a Novel Method of Data Collection

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Jelena Krivokapić

2017-03-01

Full Text Available The primary goal of this work is to examine prosodic structure as expressed concurrently through articulatory and manual gestures. Specifically, we investigated the effects of phrase-level prominence (Experiment 1 and of prosodic boundaries (Experiments 2 and 3 on the kinematic properties of oral constriction and manual gestures. The hypothesis guiding this work is that prosodic structure will be similarly expressed in both modalities. To test this, we have developed a novel method of data collection that simultaneously records speech audio, vocal tract gestures (using electromagnetic articulometry and manual gestures (using motion capture. This method allows us, for the first time, to investigate kinematic properties of body movement and vocal tract gestures simultaneously, which in turn allows us to examine the relationship between speech and body gestures with great precision. A second goal of the paper is thus to establish the validity of this method. Results from two speakers show that manual and oral gestures lengthen under prominence and at prosodic boundaries, indicating that the effects of prosodic structure extend beyond the vocal tract to include body movement.1
New Methods for Prosodic Transcription: Capturing Variability as a Source of Information

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Jennifer Cole

2016-06-01

Full Text Available Understanding the role of prosody in encoding linguistic meaning and in shaping phonetic form requires the analysis of prosodically annotated speech drawn from a wide variety of speech materials. Yet obtaining accurate and reliable prosodic annotations for even small datasets is challenging due to the time and expertise required. We discuss several factors that make prosodic annotation difficult and impact its reliability, all of which relate to 'variability': in the patterning of prosodic elements (features and structures as they relate to the linguistic and discourse context, in the acoustic cues for those prosodic elements, and in the parameter values of the cues. We propose two novel methods for prosodic transcription that capture variability as a source of information relevant to the linguistic analysis of prosody. The first is 'Rapid Prosody Transcription '(RPT, which can be performed by non-experts using a simple set of unary labels to mark prominence and boundaries based on immediate auditory impression. Inter-transcriber variability is used to calculate continuous-valued prosody ‘scores’ that are assigned to each word and represent the perceptual salience of its prosodic features or structure. RPT can be used to model the relative influence of top-down factors and acoustic cues in prosody perception, and to model prosodic variation across many dimensions, including language variety,speech style, or speaker’s affect. The second proposed method is the identification of individual cues to the contrastive prosodic elements of an utterance. Cue specification provides a link between the contrastive symbolic categories of prosodic structures and the continuous-valued parameters in the acoustic signal, and offers a framework for investigating how factors related to the grammatical and situational context influence the phonetic form of spoken words and phrases. While cue specification as a transcription tool has not yet been explored as
Preparation of edge states by shaking boundaries

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Shi, Z.C. [Department of Physics, Fuzhou University, Fuzhou 350002 (China); Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun 130024 (China); Hou, S.C. [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan (China); Wang, L.C. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Yi, X.X., E-mail: yixx@nenu.edu.cn [Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun 130024 (China)

2016-10-15

Preparing topological states of quantum matter, such as edge states, is one of the most important directions in condensed matter physics. In this work, we present a proposal to prepare edge states in Aubry–André–Harper (AAH) model with open boundaries, which takes advantage of Lyapunov control to design operations. We show that edge states can be obtained with almost arbitrary initial states. A numerical optimalization for the control is performed and the dependence of control process on the system size is discussed. The merit of this proposal is that the shaking exerts only on the boundaries of the model. As a by-product, a topological entangled state is achieved by elaborately designing the shaking scheme.
The Nature of Hemispheric Specialization for Linguistic and Emotional Prosodic Perception: A Meta-Analysis of the Lesion Literature

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Witteman, Jurriaan; van IJzendoorn, Marinus H.; van de Velde, Daan; van Heuven, Vincent J. J. P.; Schiller, Niels O.

2011-01-01

It is unclear whether there is hemispheric specialization for prosodic perception and, if so, what the nature of this hemispheric asymmetry is. Using the lesion-approach, many studies have attempted to test whether there is hemispheric specialization for emotional and linguistic prosodic perception by examining the impact of left vs. right…
Edge states in a ferromagnetic honeycomb lattice with armchair boundaries

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Pantaleón, Pierre A.; Xian, Y.

2018-02-01

We investigate the properties of magnon edge states in a ferromagnetic honeycomb lattice with armchair boundaries. In contrast with fermionic graphene, we find novel edge states due to the missing bonds along the boundary sites. After introducing an external on-site potential at the outermost sites we find that the energy spectra of the edge states are tunable. Additionally, when a non-trivial gap is induced, we find that some of the edge states are topologically protected and also tunable. Our results may explain the origin of the novel edge states recently observed in photonic lattices. We also discuss the behavior of these edge states for further experimental confirmations.
Edge Plasma Boundary Layer Generated By Kink Modes in Tokamaks

International Nuclear Information System (INIS)

Zakharov, L.E.

2010-01-01

This paper describes the structure of the electric current generated by external kink modes at the plasma edge using the ideally conducting plasma model. It is found that the edge current layer is created by both wall touching and free boundary kink modes. Near marginal stability, the total edge current has a universal expression as a result of partial compensation of the (delta)-functional surface current by the bulk current at the edge. The resolution of an apparent paradox with the pressure balance across the plasma boundary in the presence of the surface currents is provided.
Modeling of Airfoil Trailing Edge Flap with Immersed Boundary Method

DEFF Research Database (Denmark)

Zhu, Wei Jun; Shen, Wen Zhong; Sørensen, Jens Nørkær

2011-01-01

The present work considers incompressible flow over a 2D airfoil with a deformable trailing edge. The aerodynamic characteristics of an airfoil with a trailing edge flap is numerically investigated using computational fluid dynamics. A novel hybrid immersed boundary (IB) technique is applied...... to simulate the moving part of the trailing edge. Over the main fixed part of the airfoil the Navier-Stokes (NS) equations are solved using a standard body-fitted finite volume technique whereas the moving trailing edge flap is simulated with the immersed boundary method on a curvilinear mesh. The obtained...... results show that the hybrid approach is an efficient and accurate method for solving turbulent flows past airfoils with a trailing edge flap and flow control using trailing edge flap is an efficient way to regulate the aerodynamic loading on airfoils....
Hybrid immersed boundary method for airfoils with a trailing-edge flap

DEFF Research Database (Denmark)

Zhu, Wei Jun; Behrens, Tim; Shen, Wen Zhong

2013-01-01

In this paper, a hybrid immersed boundary technique has been developed for simulating turbulent flows past airfoils with moving trailing-edge flaps. Over the main fixed part of the airfoil, the equations are solved using a standard body-fitted finite volume technique, whereas the moving trailing......-edge flap is simulated using the immersed boundary method on a curvilinear mesh. An existing in-house-developed flow solver is employed to solve the incompressible Reynolds-Averaged Navier-Stokes equations together with the k-ω turbulence model. To achieve consistent wall boundary conditions at the immersed...... boundaries the k-ωturbulence model is modified and adapted to the local conditions associated with the immersed boundary method. The obtained results show that the hybrid approach is an efficient and accurate method for solving turbulent flows past airfoils with a trailing-edge flap and that flow control...

Zebra finches are sensitive to prosodic features of human speech.

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Spierings, Michelle J; ten Cate, Carel

2014-07-22

Variation in pitch, amplitude and rhythm adds crucial paralinguistic information to human speech. Such prosodic cues can reveal information about the meaning or emphasis of a sentence or the emotional state of the speaker. To examine the hypothesis that sensitivity to prosodic cues is language independent and not human specific, we tested prosody perception in a controlled experiment with zebra finches. Using a go/no-go procedure, subjects were trained to discriminate between speech syllables arranged in XYXY patterns with prosodic stress on the first syllable and XXYY patterns with prosodic stress on the final syllable. To systematically determine the salience of the various prosodic cues (pitch, duration and amplitude) to the zebra finches, they were subjected to five tests with different combinations of these cues. The zebra finches generalized the prosodic pattern to sequences that consisted of new syllables and used prosodic features over structural ones to discriminate between stimuli. This strong sensitivity to the prosodic pattern was maintained when only a single prosodic cue was available. The change in pitch was treated as more salient than changes in the other prosodic features. These results show that zebra finches are sensitive to the same prosodic cues known to affect human speech perception. © 2014 The Author(s) Published by the Royal Society. All rights reserved.
Boundaries in ground beetle (Coleoptera: Carabidae) and environmental variables at the edges of forest patches with residential developments.

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Davis, Doreen E; Gagné, Sara A

2018-01-01

Few studies of edge effects on wildlife objectively identify habitat edges or explore non-linear responses. In this paper, we build on ground beetle (Coleoptera: Carabidae) research that has begun to address these domains by using triangulation wombling to identify boundaries in beetle community structure and composition at the edges of forest patches with residential developments. We hypothesized that edges are characterized by boundaries in environmental variables that correspond to marked discontinuities in vegetation structure between maintained yards and forest. We expected environmental boundaries to be associated with beetle boundaries. We collected beetles and measured environmental variables in 200 m by 200 m sampling grids centered at the edges of three forest patches, each with a rural, suburban, or urban context, in Charlotte, North Carolina, USA. We identified boundaries within each grid at two spatial scales and tested their significance and overlap using boundary statistics and overlap statistics, respectively. We complemented boundary delineation with k -means clustering. Boundaries in environmental variables, such as temperature, grass cover, and leaf litter depth, occurred at or near the edges of all three sites, in many cases at both scales. The beetle variables that exhibited the most pronounced boundary structure in relation to edges were total species evenness, generalist abundance, generalist richness, generalist evenness, and Agonum punctiforme abundance. Environmental and beetle boundaries also occurred within forest patches and residential developments, indicating substantial localized spatial variation on either side of edges. Boundaries in beetle and environmental variables that displayed boundary structure at edges significantly overlapped, as did boundaries on either side of edges. The comparison of boundaries and clusters revealed that boundaries formed parts of the borders of patches of similar beetle or environmental condition. We
Boundaries in ground beetle (Coleoptera: Carabidae and environmental variables at the edges of forest patches with residential developments

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Doreen E. Davis

2018-01-01

Full Text Available Background Few studies of edge effects on wildlife objectively identify habitat edges or explore non-linear responses. In this paper, we build on ground beetle (Coleoptera: Carabidae research that has begun to address these domains by using triangulation wombling to identify boundaries in beetle community structure and composition at the edges of forest patches with residential developments. We hypothesized that edges are characterized by boundaries in environmental variables that correspond to marked discontinuities in vegetation structure between maintained yards and forest. We expected environmental boundaries to be associated with beetle boundaries. Methods We collected beetles and measured environmental variables in 200 m by 200 m sampling grids centered at the edges of three forest patches, each with a rural, suburban, or urban context, in Charlotte, North Carolina, USA. We identified boundaries within each grid at two spatial scales and tested their significance and overlap using boundary statistics and overlap statistics, respectively. We complemented boundary delineation with k-means clustering. Results Boundaries in environmental variables, such as temperature, grass cover, and leaf litter depth, occurred at or near the edges of all three sites, in many cases at both scales. The beetle variables that exhibited the most pronounced boundary structure in relation to edges were total species evenness, generalist abundance, generalist richness, generalist evenness, and Agonum punctiforme abundance. Environmental and beetle boundaries also occurred within forest patches and residential developments, indicating substantial localized spatial variation on either side of edges. Boundaries in beetle and environmental variables that displayed boundary structure at edges significantly overlapped, as did boundaries on either side of edges. The comparison of boundaries and clusters revealed that boundaries formed parts of the borders of patches of
The influence of boundary features on grassland-edge communities of Alta Murgia

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Cassano, Stefania; Alignier, Audrey; Forte, Luigi; Labadessa, Rocco; Mairota, Paola

2016-01-01

Many studies suggest the importance of boundary features on plant community dynamics. Our aim was to investigate the influence of boundary features on edge plant assemblages in semi-natural dry grasslands. For this purpose we selected 16 grassland edges in the central portion of the Natura 2000 site Murgia Alta, in southeastern Italy. These sites were selected according to a combination of boundary features, i.e. the adjoining land use type (road or cereal crop), slope (grassland tilted towar...
Social Boundaries and Secularism in the Lebanese Left

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Haugbølle, Sune

2013-01-01

This article explores the social meaning of boundaries in Lebanon through debates about secularism in and around the Lebanese Left. The aim is to elucidate the political and social meaning of ‘Left’ in a Lebanese context, and the positioning of liminal political subjectivity in a system organized...... along sectarian boundaries. Based on readings of debates about secularism in 1975 and 1976, the article proposes that the Left has since that year been forced to embrace secularism as its primary ideological marker. This experience in turn has become constitutive for what it means to be a leftist...
Prosodic Perception Problems in Spanish Dyslexia

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Cuetos, Fernando; Martínez-García, Cristina; Suárez-Coalla, Paz

2018-01-01

The aim of this study was to investigate the prosody abilities on top of phonological and visual abilities in children with dyslexia in Spanish that can be considered a syllable-timed language. The performances on prosodic tasks (prosodic perception, rise-time perception), phonological tasks (phonological awareness, rapid naming, verbal working…
Prosodic Similarity Effects in Short-Term Memory in Developmental Dyslexia.

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Goswami, Usha; Barnes, Lisa; Mead, Natasha; Power, Alan James; Leong, Victoria

2016-11-01

Children with developmental dyslexia are characterized by phonological difficulties across languages. Classically, this 'phonological deficit' in dyslexia has been investigated with tasks using single-syllable words. Recently, however, several studies have demonstrated difficulties in prosodic awareness in dyslexia. Potential prosodic effects in short-term memory have not yet been investigated. Here we create a new instrument based on three-syllable words that vary in stress patterns, to investigate whether prosodic similarity (the same prosodic pattern of stressed and unstressed syllables) exerts systematic effects on short-term memory. We study participants with dyslexia and age-matched and younger reading-level-matched typically developing controls. We find that all participants, including dyslexic participants, show prosodic similarity effects in short-term memory. All participants exhibited better retention of words that differed in prosodic structure, although participants with dyslexia recalled fewer words accurately overall compared to age-matched controls. Individual differences in prosodic memory were predicted by earlier vocabulary abilities, by earlier sensitivity to syllable stress and by earlier phonological awareness. To our knowledge, this is the first demonstration of prosodic similarity effects in short-term memory. The implications of a prosodic similarity effect for theories of lexical representation and of dyslexia are discussed. © 2016 The Authors. Dyslexia published by John Wiley & Sons Ltd. © 2016 The Authors. Dyslexia published by John Wiley & Sons Ltd.
Prosodic Parallelism – comparing spoken and written language

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Richard Wiese

2016-10-01

Full Text Available The Prosodic Parallelism hypothesis claims adjacent prosodic categories to prefer identical branching of internal adjacent constituents. According to Wiese and Speyer (2015, this preference implies feet contained in the same phonological phrase to display either binary or unary branching, but not different types of branching. The seemingly free schwa-zero alternations at the end of some words in German make it possible to test this hypothesis. The hypothesis was successfully tested by conducting a corpus study which used large-scale bodies of written German. As some open questions remain, and as it is unclear whether Prosodic Parallelism is valid for the spoken modality as well, the present study extends this inquiry to spoken German. As in the previous study, the results of a corpus analysis recruiting a variety of linguistic constructions are presented. The Prosodic Parallelism hypothesis can be demonstrated to be valid for spoken German as well as for written German. The paper thus contributes to the question whether prosodic preferences are similar between the spoken and written modes of a language. Some consequences of the results for the production of language are discussed.
Effect of leading-edge geometry on boundary-layer receptivity to freestream sound

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Lin, Nay; Reed, Helen L.; Saric, W. S.

1991-01-01

The receptivity to freestream sound of the laminar boundary layer over a semi-infinite flat plate with an elliptic leading edge is simulated numerically. The incompressible flow past the flat plate is computed by solving the full Navier-Stokes equations in general curvilinear coordinates. A finite-difference method which is second-order accurate in space and time is used. Spatial and temporal developments of the Tollmien-Schlichting wave in the boundary layer, due to small-amplitude time-harmonic oscillations of the freestream velocity that closely simulate a sound wave travelling parallel to the plate, are observed. The effect of leading-edge curvature is studied by varying the aspect ratio of the ellipse. The boundary layer over the flat plate with a sharper leading edge is found to be less receptive. The relative contribution of the discontinuity in curvature at the ellipse-flat-plate juncture to receptivity is investigated by smoothing the juncture with a polynomial. Continuous curvature leads to less receptivity. A new geometry of the leading edge, a modified super ellipse, which provides continuous curvature at the juncture with the flat plate, is used to study the effect of continuous curvature and inherent pressure gradient on receptivity.
Robust emotion recognition using spectral and prosodic features

CERN Document Server

Rao, K Sreenivasa

2013-01-01

In this brief, the authors discuss recently explored spectral (sub-segmental and pitch synchronous) and prosodic (global and local features at word and syllable levels in different parts of the utterance) features for discerning emotions in a robust manner. The authors also delve into the complementary evidences obtained from excitation source, vocal tract system and prosodic features for the purpose of enhancing emotion recognition performance. Features based on speaking rate characteristics are explored with the help of multi-stage and hybrid models for further improving emotion recognition performance. Proposed spectral and prosodic features are evaluated on real life emotional speech corpus.
Prosodic structure as a parallel to musical structure

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Christopher Cullen Heffner

2015-12-01

Full Text Available What structural properties do language and music share? Although early speculation identified a wide variety of possibilities, the literature has largely focused on the parallels between musical structure and syntactic structure. Here, we argue that parallels between musical structure and prosodic structure deserve more attention. We review the evidence for a link between musical and prosodic structure and find it to be strong. In fact, certain elements of prosodic structure may provide a parsimonious comparison with musical structure without sacrificing empirical findings related to the parallels between language and music. We then develop several predictions related to such a hypothesis.
Executive Functions and Prosodic Abilities in Children With High-Functioning Autism

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Marisa G. Filipe

2018-03-01

Full Text Available Little is known about the relationship between prosodic abilities and executive function skills. As deficits in executive functions (EFs and prosodic impairments are characteristics of autism, we examined how EFs are related to prosodic performance in children with high-functioning autism (HFA. Fifteen children with HFA (M = 7.4 years; SD = 1.12, matched to 15 typically developing peers on age, gender, and non-verbal intelligence participated in the study. The Profiling Elements of Prosody in Speech-Communication (PEPS-C was used to assess prosodic performance. The Children’s Color Trails Test (CCTT-1, CCTT-2, and CCTT Interference Index was used as an indicator of executive control abilities. Our findings suggest no relation between prosodic abilities and visual search and processing speed (assessed by CCTT-1, but a significant link between prosodic skills and divided attention, working memory/sequencing, set-switching, and inhibition (assessed by CCTT-2 and CCTT Interference Index. These findings may be of clinical relevance since difficulties in EFs and prosodic deficits are characteristic of many neurodevelopmental disorders. Future studies are needed to further investigate the nature of the relationship between impaired prosody and executive (dysfunction.
Minimal prosodic stems/words in Malawian Tonga: A Morpheme ...

African Journals Online (AJOL)

the level of prosodic stem analysis in this language (see Mtenje,. 2006; Mkochi ..... results into the generation of the surface minimal prosodic stems/words in. ciTonga. .... asymmetry. Natural Language and Linguistic Theory (2006) 24, 179-.
Palatalization and Intrinsic Prosodic Vowel Features in Russian

Science.gov (United States)

Ordin, Mikhail

2011-01-01

The presented study is aimed at investigating the interaction of palatalization and intrinsic prosodic features of the vowel in CVC (consonant+vowel+consonant) syllables in Russian. The universal nature of intrinsic prosodic vowel features was confirmed with the data from the Russian language. It was found that palatalization of the consonants…
Deriving prosodic structures

NARCIS (Netherlands)

Günes, Güliz

2015-01-01

When we speak, we speak in prosodic chunks. That is, in the speech flow, we produce sound strings that are systematically parsed into intonational units. The parsing procedure not only eases the production of the speaker, but it also provides the hearer clues about how units of meaning interact in
Early Verb Constructions in French: Adjacency on the Left Edge

Science.gov (United States)

Veneziano, Edy; Clark, Eve V.

2016-01-01

Children acquiring French elaborate their early verb constructions by adding adjacent morphemes incrementally at the left edge of core verbs. This hypothesis was tested with 2657 verb uses from four children between 1;3 and 2;7. Consistent with the Adjacency Hypothesis, children added clitic subjects frst only to present tense forms (as in…
On the asymptotic of solutions of elliptic boundary value problems in domains with edges

International Nuclear Information System (INIS)

Nkemzi, B.

2005-10-01

Solutions of elliptic boundary value problems in three-dimensional domains with edges may exhibit singularities. The usual procedure to study these singularities is by the application of the classical Mellin transformation or continuous Fourier transformation. In this paper, we show how the asymptotic behavior of solutions of elliptic boundary value problems in general three-dimensional domains with straight edges can be investigated by means of discrete Fourier transformation. We apply this approach to time-harmonic Maxwell's equations and prove that the singular solutions can fully be described in terms of Fourier series. The representation here can easily be used to approximate three-dimensional stress intensity factors associated with edge singularities. (author)
Boundaries in ground beetle (Coleoptera: Carabidae) and environmental variables at the edges of forest patches with residential developments

OpenAIRE

Davis, Doreen E.; Gagné, Sara A.

2018-01-01

Background Few studies of edge effects on wildlife objectively identify habitat edges or explore non-linear responses. In this paper, we build on ground beetle (Coleoptera: Carabidae) research that has begun to address these domains by using triangulation wombling to identify boundaries in beetle community structure and composition at the edges of forest patches with residential developments. We hypothesized that edges are characterized by boundaries in environmental variables that correspond...
Phonological abilities in literacy-impaired children: Brain potentials reveal deficient phoneme discrimination, but intact prosodic processing

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Claudia Männel

2017-02-01

Full Text Available Intact phonological processing is crucial for successful literacy acquisition. While individuals with difficulties in reading and spelling (i.e., developmental dyslexia are known to experience deficient phoneme discrimination (i.e., segmental phonology, findings concerning their prosodic processing (i.e., suprasegmental phonology are controversial. Because there are no behavior-independent studies on the underlying neural correlates of prosodic processing in dyslexia, these controversial findings might be explained by different task demands. To provide an objective behavior-independent picture of segmental and suprasegmental phonological processing in impaired literacy acquisition, we investigated event-related brain potentials during passive listening in typically and poor-spelling German school children. For segmental phonology, we analyzed the Mismatch Negativity (MMN during vowel length discrimination, capturing automatic auditory deviancy detection in repetitive contexts. For suprasegmental phonology, we analyzed the Closure Positive Shift (CPS that automatically occurs in response to prosodic boundaries. Our results revealed spelling group differences for the MMN, but not for the CPS, indicating deficient segmental, but intact suprasegmental phonological processing in poor spellers. The present findings point towards a differential role of segmental and suprasegmental phonology in literacy disorders and call for interventions that invigorate impaired literacy by utilizing intact prosody in addition to training deficient phonemic awareness.
Effects of suture position on left ventricular fluid mechanics under mitral valve edge-to-edge repair.

Science.gov (United States)

Du, Dongxing; Jiang, Song; Wang, Ze; Hu, Yingying; He, Zhaoming

2014-01-01

Mitral valve (MV) edge-to-edge repair (ETER) is a surgical procedure for the correction of mitral valve regurgitation by suturing the free edge of the leaflets. The leaflets are often sutured at three different positions: central, lateral and commissural portions. To study the effects of position of suture on left ventricular (LV) fluid mechanics under mitral valve ETER, a parametric model of MV-LV system during diastole was developed. The distribution and development of vortex and atrio-ventricular pressure under different suture position were investigated. Results show that the MV sutured at central and lateral in ETER creates two vortex rings around two jets, compared with single vortex ring around one jet of the MV sutured at commissure. Smaller total orifices lead to a higher pressure difference across the atrio-ventricular leaflets in diastole. The central suture generates smaller wall shear stresses than the lateral suture, while the commissural suture generated the minimum wall shear stresses in ETER.

Acoustic constituents of prosodic typology

Science.gov (United States)

Komatsu, Masahiko

Different languages sound different, and considerable part of it derives from the typological difference of prosody. Although such difference is often referred to as lexical accent types (stress accent, pitch accent, and tone; e.g. English, Japanese, and Chinese respectively) and rhythm types (stress-, syllable-, and mora-timed rhythms; e.g. English, Spanish, and Japanese respectively), it is unclear whether these types are determined in terms of acoustic properties, The thesis intends to provide a potential basis for the description of prosody in terms of acoustics. It argues for the hypothesis that the source component of the source-filter model (acoustic features) approximately corresponds to prosody (linguistic features) through several experimental-phonetic studies. The study consists of four parts. (1) Preliminary experiment: Perceptual language identification tests were performed using English and Japanese speech samples whose frequency spectral information (i.e. non-source component) is heavily reduced. The results indicated that humans can discriminate languages with such signals. (2) Discussion on the linguistic information that the source component contains: This part constitutes the foundation of the argument of the thesis. Perception tests of consonants with the source signal indicated that the source component carries the information on broad categories of phonemes that contributes to the creation of rhythm. (3) Acoustic analysis: The speech samples of Chinese, English, Japanese, and Spanish, differing in prosodic types, were analyzed. These languages showed difference in acoustic characteristics of the source component. (4) Perceptual experiment: A language identification test for the above four languages was performed using the source signal with its acoustic features parameterized. It revealed that humans can discriminate prosodic types solely with the source features and that the discrimination is easier as acoustic information increases. The
Imitated prosodic fluency predicts reading comprehension ability in good and poor high school readers

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Mara Breen

2016-07-01

Full Text Available Researchers have established a relationship between beginning readers’ silent comprehension ability and their prosodic fluency, such that readers who read aloud with appropriate prosody tend to have higher scores on silent reading comprehension assessments. The current study was designed to investigate this relationship in two groups of high school readers: Specifically Poor Comprehenders (SPCs, who have adequate word level and phonological skills but poor reading comprehension ability, and a group of age- and decoding skill-matched controls. We compared the prosodic fluency of the two groups by determining how effectively they produced prosodic cues to syntactic and semantic structure in imitations of a model speaker’s production of syntactically and semantically varied sentences. Analyses of pitch and duration patterns revealed that speakers in both groups produced the expected prosodic patterns; however, controls provided stronger durational cues to syntactic structure. These results demonstrate that the relationship between prosodic fluency and reading comprehension continues past the stage of early reading instruction. Moreover, they suggest that prosodically fluent speakers may also generate more fluent implicit prosodic representations during silent reading, leading to more effective comprehension.
Interaction between the intrinsic edge state and the helical boundary state of topological insulator phase in bilayer graphene

Energy Technology Data Exchange (ETDEWEB)

Lü, Xiaoling [School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Jiang, Liwei [National Laboratory of Superhard Materials, Department of Physics, Jilin University, Changchun 130012 (China); Zheng, Yisong, E-mail: zhengys@jlu.edu.cn [National Laboratory of Superhard Materials, Department of Physics, Jilin University, Changchun 130012 (China)

2016-04-22

Graphene has intrinsic edge states localized at zigzag edge or lattice defect. Helical boundary states can also be established in such a two-dimensional carbon material at the boundary of topological insulator (TI) phase realized by the extrinsic Rashba spin–orbital coupling (SOC) in gated bilayer graphene. We theoretically investigate the interaction between these two kinds of edge (boundary) states when they coexist in a bilayer graphene. We find that this interaction gives rise to some very interesting results. In a zigzag edged nanoribbon of bilayer graphene, it is possible that the TI helical state does not localize at the TI phase boundary. Instead it moves to the nanoribbon edge even though the SOC is absent therein. In a bulk lattice of bilayer graphene embedded with two line defects, the numbers of helical state subbands at the two line defects are not equal to each other. In such a case, the backscattering lacking is still forbidden since the Kramers pairs are valley polarized. - Highlights: • The TI helical state moves to nanoribbon edge in a gated ZENR-BG. • The gapless modes of LD-BG at the two line defects are not equal to each other. • The Kramers pairs are still valley polarized in a gated LD-BG.
Prosodic Contrasts in Ironic Speech

Science.gov (United States)

Bryant, Gregory A.

2010-01-01

Prosodic features in spontaneous speech help disambiguate implied meaning not explicit in linguistic surface structure, but little research has examined how these signals manifest themselves in real conversations. Spontaneously produced verbal irony utterances generated between familiar speakers in conversational dyads were acoustically analyzed…
Kinematic differentiation of prosodic categories in normal and disordered language development.

Science.gov (United States)

Goffman, Lisa

2004-10-01

Prosody is complex and hierarchically organized but is realized as rhythmic movement sequences. Thus, observations of the development of rhythmic aspects of movement can provide insight into links between motor and language processes, specifically whether prosodic distinctions (e.g., feet and prosodic words) are instantiated in rhythmic movement output. This experiment examined 4-7-year-old children's (both normally developing and specifically language impaired) and adults' productions of prosodic sequences that were controlled for phonetic content but differed in morphosyntactic structure (i.e., content vs. function words). Primary analyses included kinematic measures of rhythmic structure (i.e., amplitude and duration of movements in weak vs. strong syllables) across content and function contexts. Findings showed that at the level of articulatory movement, adults produced distinct rhythmic categories across content and function word contexts, whereas children did not. Children with specific language impairment differed from normally developing peers only in their ability to produce well-organized and stable rhythmic movements, not in the differentiation of prosodic categories.
Leading edge effect in laminar boundary layer excitation by sound

International Nuclear Information System (INIS)

Leehey, P.; Shapiro, P.

1980-01-01

Essentially plane pure tone sound waves were directed downstream over a heavily damped smooth flat plate installed in a low turbulence (0.04%) subsonic wind tunnel. Laminar boundary layer disturbance growth rates were measured with and without sound excitation and compared with numerical results from spatial stability theory. The data indicate that the sound field and Tollmien-Schlichting (T-S) waves coexist with comparable amplitudes when the latter are damped; moreover, the response is linear. Higher early growth rates occur for excitation by sound than by stream turbulence. Theoretical considerations indicate that the boundary layer is receptive to sound excitation primarily at the test plate leading edge. (orig.)
Suppression of large edge-localized modes in high-confinement DIII-D plasmas with a stochastic magnetic boundary.

Science.gov (United States)

Evans, T E; Moyer, R A; Thomas, P R; Watkins, J G; Osborne, T H; Boedo, J A; Doyle, E J; Fenstermacher, M E; Finken, K H; Groebner, R J; Groth, M; Harris, J H; La Haye, R J; Lasnier, C J; Masuzaki, S; Ohyabu, N; Pretty, D G; Rhodes, T L; Reimerdes, H; Rudakov, D L; Schaffer, M J; Wang, G; Zeng, L

2004-06-11

A stochastic magnetic boundary, produced by an applied edge resonant magnetic perturbation, is used to suppress most large edge-localized modes (ELMs) in high confinement (H-mode) plasmas. The resulting H mode displays rapid, small oscillations with a bursty character modulated by a coherent 130 Hz envelope. The H mode transport barrier and core confinement are unaffected by the stochastic boundary, despite a threefold drop in the toroidal rotation. These results demonstrate that stochastic boundaries are compatible with H modes and may be attractive for ELM control in next-step fusion tokamaks.
Accelerated carrier recombination by grain boundary/edge defects in MBE grown transition metal dichalcogenides

Science.gov (United States)

Chen, Ke; Roy, Anupam; Rai, Amritesh; Movva, Hema C. P.; Meng, Xianghai; He, Feng; Banerjee, Sanjay K.; Wang, Yaguo

2018-05-01

Defect-carrier interaction in transition metal dichalcogenides (TMDs) plays important roles in carrier relaxation dynamics and carrier transport, which determines the performance of electronic devices. With femtosecond laser time-resolved spectroscopy, we investigated the effect of grain boundary/edge defects on the ultrafast dynamics of photoexcited carrier in molecular beam epitaxy (MBE)-grown MoTe2 and MoSe2. We found that, comparing with exfoliated samples, the carrier recombination rate in MBE-grown samples accelerates by about 50 times. We attribute this striking difference to the existence of abundant grain boundary/edge defects in MBE-grown samples, which can serve as effective recombination centers for the photoexcited carriers. We also observed coherent acoustic phonons in both exfoliated and MBE-grown MoTe2, indicating strong electron-phonon coupling in this materials. Our measured sound velocity agrees well with the previously reported result of theoretical calculation. Our findings provide a useful reference for the fundamental parameters: carrier lifetime and sound velocity and reveal the undiscovered carrier recombination effect of grain boundary/edge defects, both of which will facilitate the defect engineering in TMD materials for high speed opto-electronics.
Accelerated carrier recombination by grain boundary/edge defects in MBE grown transition metal dichalcogenides

Directory of Open Access Journals (Sweden)

Ke Chen

2018-05-01

Full Text Available Defect-carrier interaction in transition metal dichalcogenides (TMDs plays important roles in carrier relaxation dynamics and carrier transport, which determines the performance of electronic devices. With femtosecond laser time-resolved spectroscopy, we investigated the effect of grain boundary/edge defects on the ultrafast dynamics of photoexcited carrier in molecular beam epitaxy (MBE-grown MoTe2 and MoSe2. We found that, comparing with exfoliated samples, the carrier recombination rate in MBE-grown samples accelerates by about 50 times. We attribute this striking difference to the existence of abundant grain boundary/edge defects in MBE-grown samples, which can serve as effective recombination centers for the photoexcited carriers. We also observed coherent acoustic phonons in both exfoliated and MBE-grown MoTe2, indicating strong electron-phonon coupling in this materials. Our measured sound velocity agrees well with the previously reported result of theoretical calculation. Our findings provide a useful reference for the fundamental parameters: carrier lifetime and sound velocity and reveal the undiscovered carrier recombination effect of grain boundary/edge defects, both of which will facilitate the defect engineering in TMD materials for high speed opto-electronics.
ANALYZING THE SPEECH EXPRESSIVENESS USING PROSODIC DYNAMIC CONTROL

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Valentin Eugen Ghisa

2018-04-01

Full Text Available At the level of verbal communication, the prosodic support and emotional space is modelled as a nonlinear system described through some parameters extracted from the spectral model of vocal wave, respectively the outline of the fundamental frequency, the time and energy of sonorous segments, the duration of non-acoustic segments and breaks, the voice timbre etc. Through the discretised addressing of the spectral model, the aim is to optimise the prosodic characteristics extracted from local variations of the fundamental frequency, by a method of dynamic control.
Pauses in theatrical interpretation: delimitation of prosodic constituents

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Lourenço Chacon

2014-07-01

Full Text Available We intend to observe the function of a linguistic resource – the pause – in theatrical interpretation. Connected to the field of speech therapy, we search for theoretical support in the Linguistics field, mainly in prosodic phonology – specifically, we highlight intonational phrase and phonological utterance, prosodic constituents –, proposing a dialogue between these fields, regarding the work with actors. In speech therapy literature, the work with actors focuses, centrally, in organic issues involved in the vocal process, such as “misuse” or “voice abuse”. To a smaller extent, we find, in this literature, researches that emphasize issues regarding interpretation and expressive resources, besides a few emphasizing the importance of linguistic resources in interpretation. Differently, in linguistics literature, the pause is approached, to a larger extent, from the phonetic perspective, related to several language levels. In this research, we analyzed audio recordings of four actors from a same theatrical group, acting the theatrical text Brutas flores, focused on these aims: (1 detect the place where pauses happen in the interpretation of a single text by four actors; (2 survey physical characteristics of length of these pauses; (3 check to what extent the length of a pause is related to the place where it happens, regarding the prosodic limits of intonational phrases (I and phonological utterance (U. We could observe that, although the interpretation is characterized by the subjectivity of the actor, the interpretation is constructed based in the possibilities offered by the prosodic organization of the text itself, being more or less flexible.We were also able to confirm, by considering the length of VVs units containing pauses, the prosodic hierarchy proposed by Nespor & Vogel, once the length of these units in U's limits was significantly higher than the length in I's limits. Thus, our results reinforce the premise that a
The electron edge of the low latitude boundary layer during accelerated flow events

International Nuclear Information System (INIS)

Gosling, J.T.; Thomsen, M.F.; Bame, S.J.; Onsager, T.G.; Russel, C.T.

1990-01-01

Magnetosheath plasma entering the Earth's magnetosphere to populate the low latitude boundary layer, LLBL, is often accelerated to speeds considerably greater than are observed in the adjacent magnetosheath. Measurements made during such accelerated flow events reveal separate electron and ion edges to the LLBL, with the electron edge being found earthward of the ion edge. Plasma electron velocity distributions observed at the earthward edge of the LLBL are often highly structured, exhibiting large asymmetries parallel and antiparallel, as well as perpendicular, to the local magnetic field. These features can consistently be interpreted as time-of-flight effects on recently reconnected field lines, and thus are strong evidence in support of the reconnection interpretation of accelerated plasma flow events
Prosodic Focus Marking in Bai.

NARCIS (Netherlands)

Liu, Zenghui; Chen, A.; Van de Velde, Hans

2014-01-01

This study investigates prosodic marking of focus in Bai, a Sino-Tibetan language spoken in the Southwest of China, by adopting a semi-spontaneous experimental approach. Our data show that Bai speakers increase the duration of the focused constituent and reduce the duration of the post-focus
Classification with an edge: Improving semantic image segmentation with boundary detection

Science.gov (United States)

Marmanis, D.; Schindler, K.; Wegner, J. D.; Galliani, S.; Datcu, M.; Stilla, U.

2018-01-01

We present an end-to-end trainable deep convolutional neural network (DCNN) for semantic segmentation with built-in awareness of semantically meaningful boundaries. Semantic segmentation is a fundamental remote sensing task, and most state-of-the-art methods rely on DCNNs as their workhorse. A major reason for their success is that deep networks learn to accumulate contextual information over very large receptive fields. However, this success comes at a cost, since the associated loss of effective spatial resolution washes out high-frequency details and leads to blurry object boundaries. Here, we propose to counter this effect by combining semantic segmentation with semantically informed edge detection, thus making class boundaries explicit in the model. First, we construct a comparatively simple, memory-efficient model by adding boundary detection to the SEGNET encoder-decoder architecture. Second, we also include boundary detection in FCN-type models and set up a high-end classifier ensemble. We show that boundary detection significantly improves semantic segmentation with CNNs in an end-to-end training scheme. Our best model achieves >90% overall accuracy on the ISPRS Vaihingen benchmark.
A novel prosodic-information synthesizer based on recurrent fuzzy neural network for the Chinese TTS system.

Science.gov (United States)

Lin, Chin-Teng; Wu, Rui-Cheng; Chang, Jyh-Yeong; Liang, Sheng-Fu

2004-02-01

In this paper, a new technique for the Chinese text-to-speech (TTS) system is proposed. Our major effort focuses on the prosodic information generation. New methodologies for constructing fuzzy rules in a prosodic model simulating human's pronouncing rules are developed. The proposed Recurrent Fuzzy Neural Network (RFNN) is a multilayer recurrent neural network (RNN) which integrates a Self-cOnstructing Neural Fuzzy Inference Network (SONFIN) into a recurrent connectionist structure. The RFNN can be functionally divided into two parts. The first part adopts the SONFIN as a prosodic model to explore the relationship between high-level linguistic features and prosodic information based on fuzzy inference rules. As compared to conventional neural networks, the SONFIN can always construct itself with an economic network size in high learning speed. The second part employs a five-layer network to generate all prosodic parameters by directly using the prosodic fuzzy rules inferred from the first part as well as other important features of syllables. The TTS system combined with the proposed method can behave not only sandhi rules but also the other prosodic phenomena existing in the traditional TTS systems. Moreover, the proposed scheme can even find out some new rules about prosodic phrase structure. The performance of the proposed RFNN-based prosodic model is verified by imbedding it into a Chinese TTS system with a Chinese monosyllable database based on the time-domain pitch synchronous overlap add (TD-PSOLA) method. Our experimental results show that the proposed RFNN can generate proper prosodic parameters including pitch means, pitch shapes, maximum energy levels, syllable duration, and pause duration. Some synthetic sounds are online available for demonstration.
Prosodic cues to word order: what level of representation?

Directory of Open Access Journals (Sweden)

Carline eBernard

2012-10-01

Full Text Available Within language, systematic correlations exist between syntactic structure and prosody. Prosodic prominence, for instance, falls on the complement and not the head of syntactic phrases, and its realization depends on the phrasal position of the prominent element. Thus, in Japanese, a functor-final language, prominence is phrase-initial and realized as increased pitch (^Tōkyō ni ‘Tokyo to’, whereas in French, English or Italian, functor-initial languages, it manifests itself as phrase-final lengthening (to Rome. Prosody is readily available in the linguistic signal even to the youngest infants. It has, therefore, been proposed that young learners might be able to exploit its correlations with syntax to bootstrap language structure. In this study, we tested this hypothesis, investigating how 8-month-old monolingual French infants processed an artificial grammar manipulating the relative position of prosodic prominence and word frequency. In Condition 1, we created a speech stream in which the two cues, prosody and frequency, were aligned, frequent words being prosodically non-prominent and infrequent ones being prominent, as is the case in natural language (functors are prosodically minimal compared to content words. In Condition 2, the two cues were misaligned, with frequent words carrying prosodic prominence, unlike in natural language. After familiarization with the aligned or the misaligned stream in a headturn preference procedure, we tested infants’ preference for test items having a frequent word initial or a frequent word final word order. We found that infants’ familiarized with the aligned stream showed the expected preference for the frequent word initial test items, mimicking the functor-initial word order of French. Infants in the misaligned condition showed no preference. These results suggest that infants are able to use word frequency and prosody as early cues to word order and they integrate them into a coherent
Self-similar spectral structures and edge-locking hierarchy in open-boundary spin chains

International Nuclear Information System (INIS)

Haque, Masudul

2010-01-01

For an anisotropic Heisenberg (XXZ) spin chain, we show that an open boundary induces a series of approximately self-similar features at different energy scales, high up in the eigenvalue spectrum. We present a nonequilibrium phenomenon related to this fractal structure, involving states in which a connected block near the edge is polarized oppositely to the rest of the chain. We show that such oppositely polarized blocks can be 'locked' to the edge of the spin chain and that there is a hierarchy of edge-locking effects at various orders of the anisotropy. The phenomenon enables dramatic control of quantum-state transmission and magnetization control.
SUPPESSION OF LARGE EDGE LOCALIZED MODES IN HIGH CONFINEMENT DIII-D PLASMAS WITH A STOCHASTIC MAGNETIC BOUNDARY

International Nuclear Information System (INIS)

EVANS, TE; MOYER, RA; THOMAS, PR; WATKINS, JG; OSBORNE, TH; BOEDO, JA; FENSTERMACHER, ME; FINKEN, KH; GROEBNER, RJ; GROTH, M; HARRIS, JH; LAHAYE, RJ; LASNIER, CJ; MASUZAKI, S; OHYABU, N; PRETTY, D; RHODES, TL; REIMERDES, H; RUDAKOV, DL; SCHAFFER, MJ; WANG, G; ZENG, L.

2003-01-01

OAK-B135 A stochastic magnetic boundary, produced by an externally applied edge resonant magnetic perturbation, is used to suppress large edge localized modes (ELMs) in high confinement (H-mode) plasmas. The resulting H-mode displays rapid, small oscillations with a bursty character modulated by a coherent 130 Hz envelope. The H-mode transport barrier is unaffected by the stochastic boundary. The core confinement of these discharges is unaffected, despite a three-fold drop in the toroidal rotation in the plasma core. These results demonstrate that stochastic boundaries are compatible with H-modes and may be attractive for ELM control in next-step burning fusion tokamaks
Contrast-Marking Prosodic Emphasis in Williams Syndrome: Results of Detailed Phonetic Analysis

Science.gov (United States)

Ito, Kiwako; Martens, Marilee A.

2017-01-01

Background: Past reports on the speech production of individuals with Williams syndrome (WS) suggest that their prosody is anomalous and may lead to challenges in spoken communication. While existing prosodic assessments confirm that individuals with WS fail to use prosodic emphasis to express contrast, those reports typically lack detailed…
Effects of boundary-layer separation controllers on a desktop fume hood.

Science.gov (United States)

Huang, Rong Fung; Chen, Jia-Kun; Hsu, Ching Min; Hung, Shuo-Fu

2016-10-02

A desktop fume hood installed with an innovative design of flow boundary-layer separation controllers on the leading edges of the side plates, work surface, and corners was developed and characterized for its flow and containment leakage characteristics. The geometric features of the developed desktop fume hood included a rearward offset suction slot, two side plates, two side-plate boundary-layer separation controllers on the leading edges of the side plates, a slanted surface on the leading edge of the work surface, and two small triangular plates on the upper left and right corners of the hood face. The flow characteristics were examined using the laser-assisted smoke flow visualization technique. The containment leakages were measured by the tracer gas (sulphur hexafluoride) detection method on the hood face plane with a mannequin installed in front of the hood. The results of flow visualization showed that the smoke dispersions induced by the boundary-layer separations on the leading edges of the side plates and work surface, as well as the three-dimensional complex flows on the upper-left and -right corners of the hood face, were effectively alleviated by the boundary-layer separation controllers. The results of the tracer gas detection method with a mannequin standing in front of the hood showed that the leakage levels were negligibly small (≤0.003 ppm) at low face velocities (≥0.19 m/s).

Comparison of Bayesian clustering and edge detection methods for inferring boundaries in landscape genetics

Science.gov (United States)

Safner, T.; Miller, M.P.; McRae, B.H.; Fortin, M.-J.; Manel, S.

2011-01-01

Recently, techniques available for identifying clusters of individuals or boundaries between clusters using genetic data from natural populations have expanded rapidly. Consequently, there is a need to evaluate these different techniques. We used spatially-explicit simulation models to compare three spatial Bayesian clustering programs and two edge detection methods. Spatially-structured populations were simulated where a continuous population was subdivided by barriers. We evaluated the ability of each method to correctly identify boundary locations while varying: (i) time after divergence, (ii) strength of isolation by distance, (iii) level of genetic diversity, and (iv) amount of gene flow across barriers. To further evaluate the methods' effectiveness to detect genetic clusters in natural populations, we used previously published data on North American pumas and a European shrub. Our results show that with simulated and empirical data, the Bayesian spatial clustering algorithms outperformed direct edge detection methods. All methods incorrectly detected boundaries in the presence of strong patterns of isolation by distance. Based on this finding, we support the application of Bayesian spatial clustering algorithms for boundary detection in empirical datasets, with necessary tests for the influence of isolation by distance. ?? 2011 by the authors; licensee MDPI, Basel, Switzerland.
The coordination of boundary tones and its interaction with prominence.

Science.gov (United States)

Katsika, Argyro; Krivokapić, Jelena; Mooshammer, Christine; Tiede, Mark; Goldstein, Louis

2014-05-01

This study investigates the coordination of boundary tones as a function of stress and pitch accent. Boundary tone coordination has not been experimentally investigated previously, and the effect of prominence on this coordination, and whether it is lexical (stress-driven) or phrasal (pitch accent-driven) in nature is unclear. We assess these issues using a variety of syntactic constructions to elicit different boundary tones in an Electromagnetic Articulography (EMA) study of Greek. The results indicate that the onset of boundary tones co-occurs with the articulatory target of the final vowel. This timing is further modified by stress, but not by pitch accent: boundary tones are initiated earlier in words with non-final stress than in words with final stress regardless of accentual status. Visual data inspection reveals that phrase-final words are followed by acoustic pauses during which specific articulatory postures occur. Additional analyses show that these postures reach their achievement point at a stable temporal distance from boundary tone onsets regardless of stress position. Based on these results and parallel findings on boundary lengthening reported elsewhere, a novel approach to prosody is proposed within the context of Articulatory Phonology: rather than seeing prosodic (lexical and phrasal) events as independent entities, a set of coordination relations between them is suggested. The implications of this account for prosodic architecture are discussed.
Relations between segmental and motor variability in prosodically complex nonword sequences.

Science.gov (United States)

Goffman, Lisa; Gerken, Louann; Lucchesi, Julie

2007-04-01

To assess how prosodic prominence and hierarchical foot structure influence segmental and articulatory aspects of speech production, specifically segmental accuracy and variability, and oral movement trajectory variability. Thirty individuals participated: 10 young adults, 10 children who are normally developing, and 10 children diagnosed with specific language impairment. Segmental error and segmental variability and movement trajectory variability were compared in low and high prosodic prominence conditions (i.e., strong and weak syllables) and in different prosodic foot structures. Between-participants findings were that both groups of children showed more segmental error and segmental variability and more movement trajectory variability than did adults. A similar within-participant pattern of results was observed for all 3 groups. Prosodic prominence influenced both segmental and motor levels of analysis, with weak syllables produced less accurately and with more lip and jaw movement trajectory variability than strong syllables. However, hierarchical foot structure affected segmental but not motor measures of speech production accuracy and variability. Motor and segmental variables were not consistently aligned. This pattern of results has clinical implications because inferences about motor variability may not directly follow from observations of segmental variability.
Development of a prosodic database for standard Arabic

International Nuclear Information System (INIS)

Chouireb, F.; Nail, M.; Dimeh, Y.; Guerti, M.

2007-01-01

The quality of a Text-To-Speech (Tts) synthesis system depends on the naturalness and the intelligibility of the generated speech. For this reason, a high quality automatic generator of prosody is necessary. Among the most recent developments in this field, there is a growing interest for machine learning techniques, such as neural networks, classification and regression trees, Hidden Markov Models (Hamm) and other stochastic methods. All these techniques are based on the analysis of phonetically and prosodic ally labeled speech corpora. The objective of our research is to realize a prosodic a speech database for Arabic such as those available for other languages (the database Timet for English and Bosons for French etc.). (author)
The coordination of boundary tones and its interaction with prominence1

Science.gov (United States)

Katsika, Argyro; Krivokapić, Jelena; Mooshammer, Christine; Tiede, Mark; Goldstein, Louis

2014-01-01

This study investigates the coordination of boundary tones as a function of stress and pitch accent. Boundary tone coordination has not been experimentally investigated previously, and the effect of prominence on this coordination, and whether it is lexical (stress-driven) or phrasal (pitch accent-driven) in nature is unclear. We assess these issues using a variety of syntactic constructions to elicit different boundary tones in an Electromagnetic Articulography (EMA) study of Greek. The results indicate that the onset of boundary tones co-occurs with the articulatory target of the final vowel. This timing is further modified by stress, but not by pitch accent: boundary tones are initiated earlier in words with non-final stress than in words with final stress regardless of accentual status. Visual data inspection reveals that phrase-final words are followed by acoustic pauses during which specific articulatory postures occur. Additional analyses show that these postures reach their achievement point at a stable temporal distance from boundary tone onsets regardless of stress position. Based on these results and parallel findings on boundary lengthening reported elsewhere, a novel approach to prosody is proposed within the context of Articulatory Phonology: rather than seeing prosodic (lexical and phrasal) events as independent entities, a set of coordination relations between them is suggested. The implications of this account for prosodic architecture are discussed. PMID:25300341
Prosodic differences between declaratives and interrogatives in infant-directed speech.

Science.gov (United States)

Geffen, Susan; Mintz, Toben H

2017-07-01

In many languages, declaratives and interrogatives differ in word order properties, and in syntactic organization more broadly. Thus, in order to learn the distinct syntactic properties of the two sentence types, learners must first be able to distinguish them using non-syntactic information. Prosodic information is often assumed to be a useful basis for this type of discrimination, although no systematic studies of the prosodic cues available to infants have been reported. Analysis of maternal speech in three Standard American English-speaking mother-infant dyads found that polar interrogatives differed from declaratives on the patterning of pitch and duration on the final two syllables, but wh-questions did not. Thus, while prosody is unlikely to aid discrimination of declaratives from wh-questions, infant-directed speech provides prosodic information that infants could use to distinguish declaratives and polar interrogatives. We discuss how learners could leverage this information to identify all question forms, in the context of syntax acquisition.
Production and Comprehension of Prosodic Markers in Sign Language Imperatives

Directory of Open Access Journals (Sweden)

Diane Brentari

2018-05-01

Full Text Available In signed and spoken language sentences, imperative mood and the corresponding speech acts such as for instance, command, permission or advice, can be distinguished by morphosyntactic structures, but also solely by prosodic cues, which are the focus of this paper. These cues can express paralinguistic mental states or grammatical meaning, and we show that in American Sign Language (ASL, they also exhibit the function, scope, and alignment of prosodic, linguistic elements of sign languages. The production and comprehension of prosodic facial expressions and temporal patterns therefore can shed light on how cues are grammaticalized in sign languages. They can also be informative about the formal semantic and pragmatic properties of imperative types not only in ASL, but also more broadly. This paper includes three studies: one of production (Study 1 and two of comprehension (Studies 2 and 3. In Study 1, six prosodic cues are analyzed in production: temporal cues of sign and hold duration, and non-manual cues including tilts of the head, head nods, widening of the eyes, and presence of mouthings. Results of Study 1 show that neutral sentences and commands are well distinguished from each other and from other imperative speech acts via these prosodic cues alone; there is more limited differentiation among explanation, permission, and advice. The comprehension of these five speech acts is investigated in Deaf ASL signers in Study 2, and in three additional groups in Study 3: Deaf signers of German Sign Language (DGS, hearing non-signers from the United States, and hearing non-signers from Germany. Results of Studies 2 and 3 show that the ASL group performs significantly better than the other 3 groups and that all groups perform above chance for all meaning types in comprehension. Language-specific knowledge, therefore, has a significant effect on identifying imperatives based on targeted cues. Command has the most cues associated with it and is the
Structural characteristics of the shock-induced boundary layer separation extended to the leading edge

Science.gov (United States)

Tao, Y.; Liu, W. D.; Fan, X. Q.; Zhao, Y. L.

2017-07-01

For a better understanding of the local unstart of supersonic/hypersonic inlet, a series of experiments has been conducted to investigate the shock-induced boundary layer separation extended to the leading edge. Using the nanoparticle-based planar laser scattering, we recorded the fine structures of these interactions under different conditions and paid more attention to their structural characteristics. According to their features, these interactions could be divided into four types. Specifically, Type A wave pattern is similar to the classic shock wave/turbulent boundary layer interaction, and Type B wave configuration consists of an overall Mach reflection above the large scale separation bubble. Due to the gradual decrease in the size of the separation bubble, the separation bubble was replaced by several vortices (Type C wave pattern). Besides, for Type D wave configuration which exists in the local unstart inlet, there appears to be some flow spillage around the leading edge.
Linguo-cognitive and pragmatic features of the prosodic organization of English parables

Directory of Open Access Journals (Sweden)

Musiienko Yulia

2017-06-01

Full Text Available This paper highlights the results of an investigation of the cognitive and pragmatic features of prosodic loading in English parables. The analysis of the prosodic organization of directive intentions in a parable was performed by applying systematization and classification of the pragmatic aspect, structural and semantic, functional and pragmatic specificity in order to examine the process of producing and understanding the texts of English parables.
Good, bad and ugly word stress--fMRI evidence for foot structure driven processing of prosodic violations.

Science.gov (United States)

Domahs, Ulrike; Klein, Elise; Huber, Walter; Domahs, Frank

2013-06-01

Using a stress violation paradigm, we investigated whether metrical feet constrain the way prosodic patterns are processed and evaluated. Processing of correctly versus incorrectly stressed words was associated with activation in left posterior angular and retrosplenial cortex, indicating the recognition of an expected and familiar pattern, whereas the inverse contrast yielded enhanced bilateral activation in the superior temporal gyrus, reflecting higher costs in auditory (re-)analysis. More fine-grained analyses of severe versus mild stress violations revealed activations of the left superior temporal and left anterior angular gyrus whereas the opposite contrast led to frontal activations including Broca's area and its right-hemisphere homologue, suggesting that detection of mild violations lead to increased effort in working memory and deeper phonological processing. Our results provide first evidence that different incorrect stress patterns are processed in a qualitatively different way and that the underlying foot structure seems to determine potential stress positions in German words. Copyright © 2013 Elsevier Inc. All rights reserved.
Prosodic Abilities in Spanish and English Children with Williams Syndrome: A Cross-Linguistic Study

Science.gov (United States)

Martinez-Castilla, Pastora; Stojanovik, Vesna; Setter, Jane; Sotillo, Maria

2012-01-01

The aim of this study was to compare the prosodic profiles of English- and Spanish-speaking children with Williams syndrome (WS), examining cross-linguistic differences. Two groups of children with WS, English and Spanish, of similar chronological and nonverbal mental age, were compared on performance in expressive and receptive prosodic tasks…
[Edge influence of soil moisture at farmland-grassland boundary in agriculture-pasturage ecotone of northern China].

Science.gov (United States)

Liu, Hong-lai; Zhang, Wei-hua; Wang, Kun; Zhao, Na

2009-03-01

In the agriculture-pasturage ecotone of Northern China, a typical zone with linear boundary of cropland and grassland was chosen to investigate its soil moisture regime, and the moving split-window technique was adopted to study the edge influence of soil moisture at the boundary. The results showed that the edge influence was 10 m, from 6 m within grassland and 4 m within cropland, and was categorized as the acute change type boundary. Accordingly, the farmland-grassland landscape boundary could be divided into three functional zones, i.e., grassland zone, farmland zone, and compositional ecotone zone. Soil moisture content varied abruptly in the ecotone zone, but presented linear distribution in both grassland zone and farmland zone. The average soil moisture content in grassland was about 1 g x g(-1) higher than that in farmland, which was mainly caused by the decreased capillary moisture capacity of farmland. Owing to the different vegetation cover, farmland and grassland had different transpiration and evaporation, which led to the diverse soil moisture regime, making soil water potential changed and water movement from one ecosystem to another possible.
The neural substrates of impaired prosodic detection in schizophrenia and its sensorial antecedents.

Science.gov (United States)

Leitman, David I; Hoptman, Matthew J; Foxe, John J; Saccente, Erica; Wylie, Glenn R; Nierenberg, Jay; Jalbrzikowski, Maria; Lim, Kelvin O; Javitt, Daniel C

2007-03-01

Individuals with schizophrenia show severe deficits in their ability to decode emotions based upon vocal inflection (affective prosody). This study examined neural substrates of prosodic dysfunction in schizophrenia with voxelwise analysis of diffusion tensor magnetic resonance imaging (MRI). Affective prosodic performance was assessed in 19 patients with schizophrenia and 19 comparison subjects with the Voice Emotion Identification Task (VOICEID), along with measures of basic pitch perception and executive processing (Wisconsin Card Sorting Test). Diffusion tensor MRI fractional anisotropy valves were used for voxelwise correlation analyses. In a follow-up experiment, performance on a nonaffective prosodic perception task was assessed in an additional cohort of 24 patients and 17 comparison subjects. Patients showed significant deficits in VOICEID and Distorted Tunes Task performance. Impaired VOICEID performance correlated significantly with lower fractional anisotropy values within primary and secondary auditory pathways, orbitofrontal cortex, corpus callosum, and peri-amygdala white matter. Impaired Distorted Tunes Task performance also correlated with lower fractional anisotropy in auditory and amygdalar pathways but not prefrontal cortex. Wisconsin Card Sorting Test performance in schizophrenia correlated primarily with prefrontal fractional anisotropy. In the follow-up study, significant deficits were observed as well in nonaffective prosodic performance, along with significant intercorrelations among sensory, affective prosodic, and nonaffective measures. Schizophrenia is associated with both structural and functional disturbances at the level of primary auditory cortex. Such deficits contribute significantly to patients' inability to decode both emotional and semantic aspects of speech, highlighting the importance of sensorial abnormalities in social communicatory dysfunction in schizophrenia.
Electrophysiology of Sentence Processing in Aphasia: Prosodic Cues and Thematic Fit

Directory of Open Access Journals (Sweden)

Shannon M. Sheppard

2015-05-01

* [ ] Indicates prosodic contour Methods: Twenty-four healthy college-age control participants (YNCs and ten adults with a Broca’s aphasia participated in this study. Each sentence was presented aurally to the participants over headphones. ERP Data Recording & Analysis. ERPs were recorded from 32-electrode sites across the scalp according to the 10-20 system. ERPs were averaged (100ms prestimulus baseline from artifact free trials time-locked to critical words (i.e., the point of disambiguation “pleased” in the prosodic comparison, and the NP “the song”/”the beer” in the semantic comparison. Mean amplitudes were calculated in two windows: 300-500ms for the N400 effects and 500-1000ms for the P600 effects. Results: The data from our YNCs revealed a biphasic N400-P600 complex in the prosody comparison (Figure 1A. We also found an N400 effect immediately at the NP in the incongruent relative to congruent thematic fit comparison. For the prosodic comparison in the PWA group, a delayed N400 effect was found one word downstream relative to the YNC data in the prosody comparison (Figure 1B. Additionally, an N400 effect was observed in the thematic fit comparison. Discussion: The results suggests that PWA possess a delayed sensitivity to prosodic cues, which then may affect their ability to recover from misanalysis from an incorrect parse. The results also indicate that PWA are sensitive to thematic fit information and have the capacity to process this information similarly to YNCs.
The Influence of Prosodic Stress Patterns and Semantic Depth on Novel Word Learning in Typically Developing Children.

Science.gov (United States)

Gladfelter, Allison; Goffman, Lisa

2013-01-01

The goal of this study was to investigate the effects of prosodic stress patterns and semantic depth on word learning. Twelve preschool-aged children with typically developing speech and language skills participated in a word learning task. Novel words with either a trochaic or iambic prosodic pattern were embedded in one of two learning conditions, either in children's stories (semantically rich) or picture matching games (semantically sparse). Three main analyses were used to measure word learning: comprehension and production probes, phonetic accuracy, and speech motor stability. Results revealed that prosodic frequency and density influence the learnability of novel words, or that there are prosodic neighborhood density effects. The impact of semantic depth on word learning was minimal and likely depends on the amount of experience with the novel words.
Robust boundary detection of left ventricles on ultrasound images using ASM-level set method.

Science.gov (United States)

Zhang, Yaonan; Gao, Yuan; Li, Hong; Teng, Yueyang; Kang, Yan

2015-01-01

Level set method has been widely used in medical image analysis, but it has difficulties when being used in the segmentation of left ventricular (LV) boundaries on echocardiography images because the boundaries are not very distinguish, and the signal-to-noise ratio of echocardiography images is not very high. In this paper, we introduce the Active Shape Model (ASM) into the traditional level set method to enforce shape constraints. It improves the accuracy of boundary detection and makes the evolution more efficient. The experiments conducted on the real cardiac ultrasound image sequences show a positive and promising result.
A purely nonlinear route to transition approaching the edge of chaos in a boundary layer

International Nuclear Information System (INIS)

Cherubini, S; De Palma, P; Robinet, J-Ch; Bottaro, A

2012-01-01

The understanding of transition in shear flows has recently progressed along new paradigms based on the central role of coherent flow structures and their nonlinear interactions. We follow such paradigms to identify, by means of a nonlinear optimization of the energy growth at short time, the initial perturbation which most easily induces transition in a boundary layer. Moreover, a bisection procedure has been used to identify localized flow structures living on the edge of chaos, found to be populated by hairpin vortices and streaks. Such an edge structure appears to act as a relative attractor for the trajectory of the laminar base state perturbed by the initial finite-amplitude disturbances, mediating the route to turbulence of the flow, via the triggering of a regeneration cycle of Λ and hairpin structures at different space and time scales. These findings introduce a new, purely nonlinear scenario of transition in a boundary-layer flow. (paper)
Prosodic Markers of Saliency in Humorous Narratives

Science.gov (United States)

Pickering, Lucy; Corduas, Marcella; Eisterhold, Jodi; Seifried, Brenna; Eggleston, Alyson; Attardo, Salvatore

2009-01-01

Much of what we think we know about the performance of humor relies on our intuitions about prosody (e.g., "it's all about timing"); however, this has never been empirically tested. Thus, the central question addressed in this article is whether speakers mark punch lines in jokes prosodically and, if so, how. To answer this question,…
Tuning of turbulent boundary layer anisotropy for improved surface pressure and trailing-edge noise modeling

DEFF Research Database (Denmark)

Bertagnolio, Franck; Fischer, Andreas; Zhu, Wei Jun

2014-01-01

The modeling of the surface pressure spectrum beneath a turbulent boundary layer is investigated, focusing on the case of airfoil flows and associated trailing edge noise prediction using the so-called TNO model. This type of flow is characterized by the presence of an adverse pressure gradient...... along the airfoil chord. It is shown that discrepancies between measurements and results from the TNO model increase as the pressure gradient increases. The original model is modified by introducing anisotropy in the definition of the turbulent vertical velocity spectrum across the boundary layer...
A boundary integral method for numerical computation of radar cross section of 3D targets using hybrid BEM/FEM with edge elements

Science.gov (United States)

Dodig, H.

2017-11-01

This contribution presents the boundary integral formulation for numerical computation of time-harmonic radar cross section for 3D targets. Method relies on hybrid edge element BEM/FEM to compute near field edge element coefficients that are associated with near electric and magnetic fields at the boundary of the computational domain. Special boundary integral formulation is presented that computes radar cross section directly from these edge element coefficients. Consequently, there is no need for near-to-far field transformation (NTFFT) which is common step in RCS computations. By the end of the paper it is demonstrated that the formulation yields accurate results for canonical models such as spheres, cubes, cones and pyramids. Method has demonstrated accuracy even in the case of dielectrically coated PEC sphere at interior resonance frequency which is common problem for computational electromagnetic codes.

Explaining Phonology and Reading in Adult Learners: Introducing Prosodic Awareness and Executive Functions to Reading Ability

Science.gov (United States)

Chan, Jessica S.; Wade-Woolley, Lesly

2018-01-01

Background: This study was designed to extend our understanding of phonology and reading to include suprasegmental awareness using measures of prosodic awareness, which are complex tasks that tap into the rhythmic aspects of phonology. By requiring participants to access, reflect on and manipulate word stress, the prosodic awareness measures used…
Development of Streamwise Counter-Rotating Vortices in Flat Plate Boundary Layer Pre-set by Leading Edge Patterns

KAUST Repository

Hasheminejad, S.M.; Mitsudharmadi, Hatsari; Winoto, S.H.; Low, H.T.; Lua, K.B.

2017-01-01

Development of streamwise counter-rotating vortices induced by leading edge patterns with different pattern shape is investigated using hot-wire anemometry in the boundary layer of a flat plate. A triangular, sinusoidal and notched patterns
Understanding the Contributions of Prosodic Phonology to Morphological Development: Implications for Children with Specific Language Impairment

Science.gov (United States)

Demuth, Katherine; Tomas, Ekaterina

2016-01-01

A growing body of research with typically developing children has begun to show that the acquisition of grammatical morphemes interacts not only with a developing knowledge of syntax, but also with developing abilities at the interface with prosodic phonology. In particular, a Prosodic Licensing approach to these issues provides a framework for…
Prosodic Awareness and Punctuation Ability in Adult Readers

Science.gov (United States)

Heggie, Lindsay; Wade-Woolley, Lesly

2018-01-01

We examined the relationship between two metalinguistic tasks: prosodic awareness and punctuation ability. Specifically, we investigated whether adults' ability to punctuate was related to the degree to which they are aware of and able to manipulate prosody in spoken language. English-speaking adult readers (n = 115) were administered a receptive…
Prosodic constraints on inflected words: an area of difficulty for German-speaking children with specific language impairment?

Science.gov (United States)

Kauschke, Christina; Renner, Lena; Domahs, Ulrike

2013-08-01

Recent studies suggest that morphosyntactic difficulties may result from prosodic problems. We therefore address the interface between inflectional morphology and prosody in typically developing children (TD) and children with SLI by testing whether these groups are sensitive to prosodic constraints that guide plural formation in German. A plural elicitation task was designed consisting of 60 words and 20 pseudowords. The performance of 14 German-speaking children with SLI (mean age 7.5) was compared to age-matched controls and to younger children matched for productive vocabulary. TD children performed significantly better than children with SLI. Error analyses revealed that children with SLI produced more forms that did not meet the optimal shape of a noun plural. Beyond the fact that children with SLI have deficits in plural marking, the findings suggest that they also show reduced sensitivity to prosodic requirements. In other words, the prosodic structure of inflected words seems to be vulnerable in children with SLI.
Low-Speed Wind-Tunnel Investigation of Blowing Boundary-Layer Control on Leading- and Trailing-Edge Flaps of a Large-Scale, Low-Aspect-Ratio, 45 Swept-wing Airplane Configuration

Science.gov (United States)

Maki, Ralph L.

1959-01-01

Blowing boundary-layer control was applied to the leading- and trailing-edge flaps of a 45 deg sweptback-wing complete model in a full-scale low-speed wind-tunnel study. The principal purpose of the study was to determine the effects of leading-edge flap deflection and boundary-layer control on maximum lift and longitudinal stability. Leading-edge flap deflection alone was sufficient to maintain static longitudinal stability without trailing-edge flaps. However, leading-edge flap blowing was required to maintain longitudinal stability by delaying leading-edge flow separation when trailing-edge flaps were deflected either with or without blowing. Partial-span leading-edge flaps deflected 60 deg with moderate blowing gave the major increase in maximum lift, although higher deflection and additional blowing gave some further increase. Inboard of 0.4 semispan leading-edge flap deflection could be reduced to 40 deg and/or blowing could be omitted with only small loss in maximum lift. Trailing-edge flap lift increments were increased by boundary-layer control for deflections greater than 45 deg. Maximum lift was not increased with deflected trailing-edge flaps with blowing.
Acquisition of Prosodic Focus Marking by English, French, and German Three-, Four-, Five- and Six-Year-Olds

Science.gov (United States)

Szendroi, Kriszta; Bernard, Carline; Berger, Frauke; Gervain, Judit; Hohle, Barbara

2018-01-01

Previous research on young children's knowledge of prosodic focus marking has revealed an apparent paradox, with comprehension appearing to lag behind production. Comprehension of prosodic focus is difficult to study experimentally due to its subtle and ambiguous contribution to pragmatic meaning. We designed a novel comprehension task, which…
Modelling of Edge Insulation Depending on Boundary Conditions for the Ground Level

Science.gov (United States)

Stolarska, Agata; Strzałkowski, Jarosław

2017-10-01

The article presents results of CFD software aided simulations of a thermal bridge, existing at the wall-slab on ground connection. Calculations were made for different variants of the edge insulation location. Schemes without any edge insulation, with some vertical insulation, horizontal, diagonal, and diagonal combined with insulation used as formwork under the slab on ground were analysed. Each variant was differentiated with boundary conditions for the ground. Vertical borders of the model in the ground, as well as the lower border were described in the first solution as adiabatic, while in the second case, a variable temperature value, depending on the ground depth, was set. For comparison, additional calculations were conducted for non-stationary conditions, in which the initial temperature of the ground was set to the average annual temperature of air. The calculations were based on the location of Szczecin, for which the outside air temperature was set to -16.0°C. Results obtained from the simulation were then used to determine the thermal bridge parameters, in particular, thermal coupling coefficient and linear thermal transmittance. The effect of the set of boundary conditions is clearly seen. In general, for all the five variants, lower values of heat fluxes and linear thermal transmittances were obtained, when variable temperature in the ground was assumed. From the point of view of energy balance, it is more favourable to use the values of ψg obtained when the ground temperature is taken into account. The data breakdown shows that application of the actual temperature distribution in the ground to a model has a strong effect on distribution of the 0.0°C isotherm. The adiabatic model indicates that the ground under the slab freezes, while the model, which takes into account the temperature of the ground, shows that the ground under the floor has positive temperatures and the 0.0°C isotherm reaches only the edge of the outer wall. Moreover, the
Criteria for Labelling Prosodic Aspects of English Speech.

Science.gov (United States)

Bagshaw, Paul C.; Williams, Briony J.

A study reports a set of labelling criteria which have been developed to label prosodic events in clear, continuous speech, and proposes a scheme whereby this information can be transcribed in a machine readable format. A prosody in a syllabic domain which is synchronized with a phonemic segmentation was annotated. A procedural definition of…
Evidence for a perception of prosodic cues in bat communication: contact call classification by Megaderma lyra.

Science.gov (United States)

Janssen, Simone; Schmidt, Sabine

2009-07-01

The perception of prosodic cues in human speech may be rooted in mechanisms common to mammals. The present study explores to what extent bats use rhythm and frequency, typically carrying prosodic information in human speech, for the classification of communication call series. Using a two-alternative, forced choice procedure, we trained Megaderma lyra to discriminate between synthetic contact call series differing in frequency, rhythm on level of calls and rhythm on level of call series, and measured the classification performance for stimuli differing in only one, or two, of the above parameters. A comparison with predictions from models based on one, combinations of two, or all, parameters revealed that the bats based their decision predominantly on frequency and in addition on rhythm on the level of call series, whereas rhythm on level of calls was not taken into account in this paradigm. Moreover, frequency and rhythm on the level of call series were evaluated independently. Our results show that parameters corresponding to prosodic cues in human languages are perceived and evaluated by bats. Thus, these necessary prerequisites for a communication via prosodic structures in mammals have evolved far before human speech.
Charisma in business speeches -- A contrastive acoustic-prosodic analysis of Steve Jobs and Mark Zuckerberg

OpenAIRE

Niebuhr, Oliver; Brem, Alexander; Novák-Tót, Eszter; Voße, Jana

2016-01-01

Charisma is a key component of spoken language interaction; and it is probably for this reason that charismatic speech has been the subject of intensive research for centuries. However, what is still largely missing is a quantitative and objective line of research that, firstly, involves analyses of the acoustic-prosodic signal, secondly, focuses on business speeches like product presentations, and, thirdly, in doing so, advances the still fairly fragmentary evidence on the prosodic correlate...
Conversational quality is affected by and reflected in prosodic entrainment

DEFF Research Database (Denmark)

Michalsky, Jan; Niebuhr, Oliver; Schoormann, Heike

2018-01-01

Prosodic entrainment is connected to various forms of communicative success. One possibility to assess successful communication in non-task-oriented everyday conversations is through the participants’ perception of conversational quality. In this study we investigate whether a speaker’s degree of...
Analysis of engagement behavior in children during dyadic interactions using prosodic cues.

Science.gov (United States)

Gupta, Rahul; Bone, Daniel; Lee, Sungbok; Narayanan, Shrikanth

2016-05-01

Child engagement is defined as the interaction of a child with his/her environment in a contextually appropriate manner. Engagement behavior in children is linked to socio-emotional and cognitive state assessment with enhanced engagement identified with improved skills. A vast majority of studies however rely solely, and often implicitly, on subjective perceptual measures of engagement. Access to automatic quantification could assist researchers/clinicians to objectively interpret engagement with respect to a target behavior or condition, and furthermore inform mechanisms for improving engagement in various settings. In this paper, we present an engagement prediction system based exclusively on vocal cues observed during structured interaction between a child and a psychologist involving several tasks. Specifically, we derive prosodic cues that capture engagement levels across the various tasks. Our experiments suggest that a child's engagement is reflected not only in the vocalizations, but also in the speech of the interacting psychologist. Moreover, we show that prosodic cues are informative of the engagement phenomena not only as characterized over the entire task (i.e., global cues), but also in short term patterns (i.e., local cues). We perform a classification experiment assigning the engagement of a child into three discrete levels achieving an unweighted average recall of 55.8% (chance is 33.3%). While the systems using global cues and local level cues are each statistically significant in predicting engagement, we obtain the best results after fusing these two components. We perform further analysis of the cues at local and global levels to achieve insights linking specific prosodic patterns to the engagement phenomenon. We observe that while the performance of our model varies with task setting and interacting psychologist, there exist universal prosodic patterns reflective of engagement.
Prosodic characteristics of read speech before and after treadmill running

NARCIS (Netherlands)

Trouvain, Jürgen; Truong, Khiet Phuong

Physical activity leads to a respiratory behaviour that is very different to a resting state and that influences speech production. How speech parameters are exactly affected by physical activity remains largely unknown. Hence, we investigated how several prosodic parameters change under influence
Prosodic Function Row in Persian Poetry

Directory of Open Access Journals (Sweden)

Majid Mansouri

2017-04-01

The main reason for the emergence of rows in Persian poetry is its prosodic function that has already been paid less. I just found something in the book Ghosn al-ban which the author had some similar view to the row. In this study, we made our attempt to show another reason for the entry and spread of the row in Persian poetry by means of a new approach. It should also be noted that in these lines to avoid as much as possible the repetitive and stereotyped points regarding the row.
A k · p treatment of edge states in narrow 2D topological insulators, with standard boundary conditions for the wave function and its derivative.

Science.gov (United States)

Klipstein, P C

2018-07-11

For 2D topological insulators with strong electron-hole hybridization, such as HgTe/CdTe quantum wells, the widely used 4 × 4 k · p Hamiltonian based on the first electron and heavy hole sub-bands yields an equal number of physical and spurious solutions, for both the bulk states and the edge states. For symmetric bands and zero wave vector parallel to the sample edge, the mid-gap bulk solutions are identical to the edge solutions. In all cases, the physical edge solution is exponentially localized to the boundary and has been shown previously to satisfy standard boundary conditions for the wave function and its derivative, even in the limit of an infinite wall potential. The same treatment is now extended to the case of narrow sample widths, where for each spin direction, a gap appears in the edge state dispersions. For widths greater than 200 nm, this gap is less than half of the value reported for open boundary conditions, which are called into question because they include a spurious wave function component. The gap in the edge state dispersions is also calculated for weakly hybridized quantum wells such as InAs/GaSb/AlSb. In contrast to the strongly hybridized case, the edge states at the zone center only have pure exponential character when the bands are symmetric and when the sample has certain characteristic width values.
Phrase-Final Words in Greek Storytelling Speech: A Study on the Effect of a Culturally-Specific Prosodic Feature on Short-Term Memory.

Science.gov (United States)

Loutrari, Ariadne; Tselekidou, Freideriki; Proios, Hariklia

2018-02-27

Prosodic patterns of speech appear to make a critical contribution to memory-related processing. We considered the case of a previously unexplored prosodic feature of Greek storytelling and its effect on free recall in thirty typically developing children between the ages of 10 and 12 years, using short ecologically valid auditory stimuli. The combination of a falling pitch contour and, more notably, extensive final-syllable vowel lengthening, which gives rise to the prosodic feature in question, led to statistically significantly higher performance in comparison to neutral phrase-final prosody. Number of syllables in target words did not reveal substantial difference in performance. The current study presents a previously undocumented culturally-specific prosodic pattern and its effect on short-term memory.
H-mode edge rotation in W7-AS

International Nuclear Information System (INIS)

Hirsch, M.; Baldzuhn, J.; Ehmler, H.; Grigull, P.; Maassberg, H.; McCormick, K.; Wagner, F.; Wobig, H.

2005-01-01

In W7-AS three regimes of improved confinement exist which base on negative radial electric fields at the plasma edge resulting there from ion-root conditions of the ambipolar radial fluxes. Experimental control besides the magnetic configuration is given via the edge density profile i.e. the recycling and fuelling conditions. However, the ordering element seems to be the radial electric field profile (respectively its shear) and its interplay with the gradients of ion temperature and density. At low to medium densities the so called optimum confinement regime occurs with maximum density gradients located well inside the plasma boundary and large negative values of E r extending deep in the bulk plasma. For a large inner fraction of the bulk the ion temperature can be sufficiently high that ion transport conditions already can be explained by neoclassics. This regime delivers maximum values of T i , τ e and n τ e T i . Density gradients located right inside the plasma boundary result in the classical H-mode phenomena reminiscent to other toroidal devices with the capability of an edge layer with nearly complete suppression of turbulence either quasi stationary (in a quiescent H-mode) or intermittently (in between ELMs). At even higher densities and highly collisional plasmas with the maximum of ∇n shifted to or even out of the plasma boundary the High Density H-mode (HDH) opens access to steady state conditions with no measurable impurity accumulation. These improved confinement regimes are accessed and left via significant transitions of the transport properties albeit these transitions occur on rather different timescales. A comprehensive picture of improved edge confinement regimes in W7-AS is drawn based on the assumption that a weak edge bounded transport barrier resulting from the ion root conditions (thus E r <0) is the ground state of the (turbulent) edge plasma and already behaves as a barrier for anomalous transport. On top of that the classical H
Processing of prosodic changes in natural speech stimuli in school-age children.

Science.gov (United States)

Lindström, R; Lepistö, T; Makkonen, T; Kujala, T

2012-12-01

Speech prosody conveys information about important aspects of communication: the meaning of the sentence and the emotional state or intention of the speaker. The present study addressed processing of emotional prosodic changes in natural speech stimuli in school-age children (mean age 10 years) by recording the electroencephalogram, facial electromyography, and behavioral responses. The stimulus was a semantically neutral Finnish word uttered with four different emotional connotations: neutral, commanding, sad, and scornful. In the behavioral sound-discrimination task the reaction times were fastest for the commanding stimulus and longest for the scornful stimulus, and faster for the neutral than for the sad stimulus. EEG and EMG responses were measured during non-attentive oddball paradigm. Prosodic changes elicited a negative-going, fronto-centrally distributed neural response peaking at about 500 ms from the onset of the stimulus, followed by a fronto-central positive deflection, peaking at about 740 ms. For the commanding stimulus also a rapid negative deflection peaking at about 290 ms from stimulus onset was elicited. No reliable stimulus type specific rapid facial reactions were found. The results show that prosodic changes in natural speech stimuli activate pre-attentive neural change-detection mechanisms in school-age children. However, the results do not support the suggestion of automaticity of emotion specific facial muscle responses to non-attended emotional speech stimuli in children. Copyright © 2012 Elsevier B.V. All rights reserved.
Reduction of airfoil trailing edge noise by trailing edge blowing

International Nuclear Information System (INIS)

Gerhard, T; Carolus, T; Erbslöh, S

2014-01-01

The paper deals with airfoil trailing edge noise and its reduction by trailing edge blowing. A Somers S834 airfoil section which originally was designed for small wind turbines is investigated. To mimic realistic Reynolds numbers the boundary layer is tripped on pressure and suction side. The chordwise position of the blowing slot is varied. The acoustic sources, i.e. the unsteady flow quantities in the turbulent boundary layer in the vicinity of the trailing edge, are quantified for the airfoil without and with trailing edge blowing by means of a large eddy simulation and complementary measurements. Eventually the far field airfoil noise is measured by a two-microphone filtering and correlation and a 40 microphone array technique. Both, LES-prediction and measurements showed that a suitable blowing jet on the airfoil suction side is able to reduce significantly the turbulence intensity and the induced surface pressure fluctuations in the trailing edge region. As a consequence, trailing edge noise associated with a spectral hump around 500 Hz could be reduced by 3 dB. For that a jet velocity of 50% of the free field velocity was sufficient. The most favourable slot position was at 90% chord length

Edge states and conformal boundary conditions in super spin chains and super sigma models

International Nuclear Information System (INIS)

Bondesan, Roberto; Jacobsen, Jesper L.; Saleur, Hubert

2011-01-01

The sigma models on projective superspaces CP N+M-1|N with topological angle θ=πmod2π flow to non-unitary, logarithmic conformal field theories in the low-energy limit. In this paper, we determine the exact spectrum of these theories for all open boundary conditions preserving the full global symmetry of the model, generalizing recent work on the particular case M=0 [C. Candu et al., JHEP 1002 (2010) 015]. In the sigma model setting, these boundary conditions are associated with complex line bundles, and are labelled by an integer, related with the exact value of θ. Our approach relies on a spin chain regularization, where the boundary conditions now correspond to the introduction of additional edge states. The exact values of the exponents then follow from a lengthy algebraic analysis, a reformulation of the spin chain in terms of crossing and non-crossing loops (represented as a certain subalgebra of the Brauer algebra), and earlier results on the so-called one- and two-boundary Temperley-Lieb algebras (also known as blob algebras). A remarkable result is that the exponents, in general, turn out to be irrational. The case M=1 has direct applications to the spin quantum Hall effect, which will be discussed in a sequel.
Edge states and conformal boundary conditions in super spin chains and super sigma models

Energy Technology Data Exchange (ETDEWEB)

Bondesan, Roberto, E-mail: roberto.bondesan@cea.f [LPTENS, Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris (France); Institute de Physique Theorique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Jacobsen, Jesper L. [LPTENS, Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris (France); Universite Pierre et Marie Curie, 4 place Jussieu, 75252 Paris (France); Saleur, Hubert [Institute de Physique Theorique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Physics Department, USC, Los Angeles, CA 90089-0484 (United States)

2011-08-11

The sigma models on projective superspaces CP{sup N+M-1{vert_bar}N} with topological angle {theta}={pi}mod2{pi} flow to non-unitary, logarithmic conformal field theories in the low-energy limit. In this paper, we determine the exact spectrum of these theories for all open boundary conditions preserving the full global symmetry of the model, generalizing recent work on the particular case M=0 [C. Candu et al., JHEP 1002 (2010) 015]. In the sigma model setting, these boundary conditions are associated with complex line bundles, and are labelled by an integer, related with the exact value of {theta}. Our approach relies on a spin chain regularization, where the boundary conditions now correspond to the introduction of additional edge states. The exact values of the exponents then follow from a lengthy algebraic analysis, a reformulation of the spin chain in terms of crossing and non-crossing loops (represented as a certain subalgebra of the Brauer algebra), and earlier results on the so-called one- and two-boundary Temperley-Lieb algebras (also known as blob algebras). A remarkable result is that the exponents, in general, turn out to be irrational. The case M=1 has direct applications to the spin quantum Hall effect, which will be discussed in a sequel.
The role of prominence in determining the scope of boundary-related lengthening in Greek.

Science.gov (United States)

Katsika, Argyro

2016-03-01

This study aims at examining and accounting for the scope of the temporal effect of phrase boundaries. Previous research has indicated that there is an interaction between boundary-related lengthening and prominence such that the former extends towards the nearby prominent syllable. However, it is unclear whether this interaction is due to lexical stress and/or phrasal prominence (marked by pitch accent) and how far towards the prominent syllable the effect extends. Here, we use an electromagnetic articulography (EMA) study of Greek to examine the scope of boundary-related lengthening as a function of lexical stress and pitch accent separately. Boundaries are elicited by the means of a variety of syntactic constructions.. The results show an effect of lexical stress. Phrase-final lengthening affects the articulatory gestures of the phrase-final syllable that are immediately adjacent to the boundary in words with final stress, but is initiated earlier within phrase-final words with non-final stress. Similarly, the articulatory configurations during inter-phrasal pauses reach their point of achievement later in words with final stress than in words with non-final stress. These effects of stress hold regardless of whether the phrase-final word is accented or de-accented. Phrase-initial lengthening, on the other hand, is consistently detected on the phrase-initial constriction, independently of where the stress is within the preceding, phrase-final, word. These results indicate that the lexical aspect of prominence plays a role in determining the scope of boundary-related lengthening in Greek. Based on these results, a gestural account of prosodic boundaries in Greek is proposed in which lexical and phrasal prosody interact in a systematic and coordinated fashion. The cross-linguistic dimensions of this account and its implications for prosodic structure are discussed.
Does incongruence of lexicosemantic and prosodic information cause discernible cognitive conflict?

Science.gov (United States)

Mitchell, Rachel L C

2006-12-01

We are often required to interpret discordant emotional signals. Whereas equivalent cognitive paradigms cause noticeable conflict via their behavioral and psychophysiological effects, the same may not necessarily be true for discordant emotions. Skin conductance responses (SCRs) and heart rates (HRs) were measured during a classic Stroop task and one in which the emotions conveyed by lexicosemantic content and prosody were congruent or incongruent. The participants' task was to identify the emotion conveyed by lexicosemantic content or prosody. No relationship was observed between HR and congruence. SCR was higher during incongruent than during congruent conditions of the experimental task (as well as in the classic Stroop task), but no difference in SCR was observed in a comparison between congruence effects during lexicosemantic emotion identification and those during prosodic emotion identification. It is concluded that incongruence between lexicosemantic and prosodic emotion does cause notable cognitive conflict. Functional neuroanatomic implications are discussed.
The semantics of prosody: acoustic and perceptual evidence of prosodic correlates to word meaning.

Science.gov (United States)

Nygaard, Lynne C; Herold, Debora S; Namy, Laura L

2009-01-01

This investigation examined whether speakers produce reliable prosodic correlates to meaning across semantic domains and whether listeners use these cues to derive word meaning from novel words. Speakers were asked to produce phrases in infant-directed speech in which novel words were used to convey one of two meanings from a set of antonym pairs (e.g., big/small). Acoustic analyses revealed that some acoustic features were correlated with overall valence of the meaning. However, each word meaning also displayed a unique acoustic signature, and semantically related meanings elicited similar acoustic profiles. In two perceptual tests, listeners either attempted to identify the novel words with a matching meaning dimension (picture pair) or with mismatched meaning dimensions. Listeners inferred the meaning of the novel words significantly more often when prosody matched the word meaning choices than when prosody mismatched. These findings suggest that speech contains reliable prosodic markers to word meaning and that listeners use these prosodic cues to differentiate meanings. That prosody is semantic suggests a reconceptualization of traditional distinctions between linguistic and nonlinguistic properties of spoken language. Copyright © 2009 Cognitive Science Society, Inc.
Beat gestures and prosodic prominence: impact on learning

OpenAIRE

Kushch, Olga

2018-01-01

Previous research has shown that gestures are beneficial for language learning. This doctoral thesis centers on the effects of beat gestures– i.e., hand and arm gestures that are typically associated with prosodically prominent positions in speech - on such processes. Little is known about how the two central properties of beat gestures, namely how they mark both information focus and rhythmic positions in speech, can be beneficial for learning either a first or a second language. The main go...
A Closer Look at Formulaic Language: Prosodic Characteristics of Swedish Proverbs

Science.gov (United States)

Hallin, Anna Eva; Van Lancker Sidtis, Diana

2017-01-01

Formulaic expressions (such as idioms, proverbs, and conversational speech formulas) are currently a topic of interest. Examination of prosody in formulaic utterances, a less explored property of formulaic expressions, has yielded controversial views. The present study investigates prosodic characteristics of proverbs, as one type of formulaic…
Intrinsic Compressive Stress in Polycrystalline Films is Localized at Edges of the Grain Boundaries

Science.gov (United States)

Vasco, Enrique; Polop, Celia

2017-12-01

The intrinsic compression that arises in polycrystalline thin films under high atomic mobility conditions has been attributed to the insertion or trapping of adatoms inside grain boundaries. This compression is a consequence of the stress field resulting from imperfections in the solid and causes the thermomechanical fatigue that is estimated to be responsible for 90% of mechanical failures in current devices. We directly measure the local distribution of residual intrinsic stress in polycrystalline thin films on nanometer scales, using a pioneering method based on atomic force microscopy. Our results demonstrate that, at odds with expectations, compression is not generated inside grain boundaries but at the edges of gaps where the boundaries intercept the surface. We describe a model wherein this compressive stress is caused by Mullins-type surface diffusion towards the boundaries, generating a kinetic surface profile different from the mechanical equilibrium profile by the Laplace-Young equation. Where the curvatures of both profiles differ, an intrinsic stress is generated in the form of Laplace pressure. The Srolovitz-type surface diffusion that results from the stress counters the Mullins-type diffusion and stabilizes the kinetic surface profile, giving rise to a steady compression regime. The proposed mechanism of competition between surface diffusions would explain the flux and time dependency of compressive stress in polycrystalline thin films.
The edge of space time

International Nuclear Information System (INIS)

Hawking, S.

1993-01-01

What happened at the beginning of the expansion of the universe. Did space time have an edge at the Big Bang. The answer is that, if the boundary conditions of the universe are that it has no boundary, time ceases to be well-defined in the very early universe as the direction ''north'' ceases to be well defined at the North Pole of the Earth. The quantity that we measure as time has a beginning but that does not mean spacetime has an edge, just as the surface of the Earth does not have an edge at the North Pole. 8 figs
Facial and prosodic emotion recognition in social anxiety disorder.

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Tseng, Huai-Hsuan; Huang, Yu-Lien; Chen, Jian-Ting; Liang, Kuei-Yu; Lin, Chao-Cheng; Chen, Sue-Huei

2017-07-01

Patients with social anxiety disorder (SAD) have a cognitive preference to negatively evaluate emotional information. In particular, the preferential biases in prosodic emotion recognition in SAD have been much less explored. The present study aims to investigate whether SAD patients retain negative evaluation biases across visual and auditory modalities when given sufficient response time to recognise emotions. Thirty-one SAD patients and 31 age- and gender-matched healthy participants completed a culturally suitable non-verbal emotion recognition task and received clinical assessments for social anxiety and depressive symptoms. A repeated measures analysis of variance was conducted to examine group differences in emotion recognition. Compared to healthy participants, SAD patients were significantly less accurate at recognising facial and prosodic emotions, and spent more time on emotion recognition. The differences were mainly driven by the lower accuracy and longer reaction times for recognising fearful emotions in SAD patients. Within the SAD patients, lower accuracy of sad face recognition was associated with higher severity of depressive and social anxiety symptoms, particularly with avoidance symptoms. These findings may represent a cross-modality pattern of avoidance in the later stage of identifying negative emotions in SAD. This pattern may be linked to clinical symptom severity.
Physics constraints on tokamak edge operational space and extrapolation to ITER

International Nuclear Information System (INIS)

Igitkhanov, Yu.; Janeschitz, G.; Sugihara, M.; Pacher, H.D.; Post, D.E.; Pacher, G.W.; Pogutse, O.P.

1998-01-01

This paper emphasises the theoretical understanding of the physical processes in the edge tokamak plasma and their attendant uncertainties and constraints. The various operational boundaries are represented in the edge operational space (EOS) diagram, the space of edge density and temperature, defined at the top of the H-mode transport barrier. The EOS is governed by four boundaries representing physical constraints for the edge plasma parameters. The first boundary represents the onset of type I ELM instabilities in terms of a critical pressure gradient for MHD stability at the edge which defines the maximum pedestal temperature for a given density once the width of the H-mode transport barrier at the edge (pedestal width) is known. The ideal ballooning mode is a candidate for this instability. The second boundary defines the boundary between type III ELM's, which are probably resistive MHD modes, and the ELM-free region. (orig.)
Prosodic Abilities of Spanish-Speaking Adolescents and Adults with Williams Syndrome

Science.gov (United States)

Martinez-Castilla, Pastora; Sotillo, Maria; Campos, Ruth

2011-01-01

In spite of the relevant role of prosody in communication, and in contrast with other linguistic components, there is paucity of research in this field for Williams syndrome (WS). Therefore, this study performed a systematic assessment of prosodic abilities in WS. The Spanish version of the Profiling Elements of Prosody in Speech-Communication…
Prosodic Skills in Children with Down Syndrome and in Typically Developing Children

Science.gov (United States)

Zampini, Laura; Fasolo, Mirco; Spinelli, Maria; Zanchi, Paola; Suttora, Chiara; Salerni, Nicoletta

2016-01-01

Background: Many studies have analysed language development in children with Down syndrome to understand better the nature of their linguistic delays and the reason why these delays, particularly those in the morphosyntactic area, seem greater than their cognitive impairment. However, the prosodic characteristics of language development in…
The assessment and treatment of prosodic disorders and neurological theories of prosody.

Science.gov (United States)

Diehl, Joshua J; Paul, Rhea

2009-08-01

In this article, we comment on specific aspects of Peppé (Peppé, 2009). In particular, we address the assessment and treatment of prosody in clinical settings and discuss current theory on neurological models of prosody. We argue that in order for prosodic assessment instruments and treatment programs to be clinical effective, we need assessment instruments that: (1) have a representative normative comparison sample and strong psychometric properties; (2) are based on empirical information regarding the typical sequence of prosodic acquisition and are sensitive to developmental change; (3) meaningfully subcategorize various aspects of prosody; (4) use tasks that have ecological validity; and (5) have clinical properties, such as length and ease of administration, that allow them to become part of standard language assessment batteries. In addition, we argue that current theories of prosody processing in the brain are moving toward network models that involve multiple brain areas and are crucially dependent on cortical communication. The implications of these observations for future research and clinical practice are outlined.
Age-related changes to spectral voice characteristics affect judgments of prosodic, segmental, and talker attributes for child and adult speech

Science.gov (United States)

Dilley, Laura C.; Wieland, Elizabeth A.; Gamache, Jessica L.; McAuley, J. Devin; Redford, Melissa A.

2013-01-01

Purpose As children mature, changes in voice spectral characteristics covary with changes in speech, language, and behavior. Spectral characteristics were manipulated to alter the perceived ages of talkers’ voices while leaving critical acoustic-prosodic correlates intact, to determine whether perceived age differences were associated with differences in judgments of prosodic, segmental, and talker attributes. Method Speech was modified by lowering formants and fundamental frequency, for 5-year-old children’s utterances, or raising them, for adult caregivers’ utterances. Next, participants differing in awareness of the manipulation (Exp. 1a) or amount of speech-language training (Exp. 1b) made judgments of prosodic, segmental, and talker attributes. Exp. 2 investigated the effects of spectral modification on intelligibility. Finally, in Exp. 3 trained analysts used formal prosody coding to assess prosodic characteristics of spectrally-modified and unmodified speech. Results Differences in perceived age were associated with differences in ratings of speech rate, fluency, intelligibility, likeability, anxiety, cognitive impairment, and speech-language disorder/delay; effects of training and awareness of the manipulation on ratings were limited. There were no significant effects of the manipulation on intelligibility or formally coded prosody judgments. Conclusions Age-related voice characteristics can greatly affect judgments of speech and talker characteristics, raising cautionary notes for developmental research and clinical work. PMID:23275414
Plasma boundary phenomena in tokamaks

International Nuclear Information System (INIS)

Stangeby, P.C.

1989-06-01

The focus of this review is on processes occurring at the edge, and on the connection between boundary plasma - the scrape-off layer (SOL) and the radiating layer - and central plasma processes. Techniques used for edge diagnosis are reviewed and basic experimental information (n e and T e ) is summarized. Simple models of the SOL are summarized, and the most important effects of the boundary plasma - the influence on the fuel particles, impurities, and energy - on tokamak operation dealt with. Methods of manipulating and controlling edge conditions in tokamaks and the experimental data base for the edge during auxiliary heating of tokamaks are reviewed. Fluctuations and asymmetries at the edge are also covered. (9 tabs., 134 figs., 879 refs.)
Prosodic influences on speech production in children with specific language impairment and speech deficits: kinematic, acoustic, and transcription evidence.

Science.gov (United States)

Goffman, L

1999-12-01

It is often hypothesized that young children's difficulties with producing weak-strong (iambic) prosodic forms arise from perceptual or linguistically based production factors. A third possible contributor to errors in the iambic form may be biological constraints, or biases, of the motor system. In the present study, 7 children with specific language impairment (SLI) and speech deficits were matched to same age peers. Multiple levels of analysis, including kinematic (modulation and stability of movement), acoustic, and transcription, were applied to children's productions of iambic (weak-strong) and trochaic (strong-weak) prosodic forms. Findings suggest that a motor bias toward producing unmodulated rhythmic articulatory movements, similar to that observed in canonical babbling, contribute to children's acquisition of metrical forms. Children with SLI and speech deficits show less mature segmental and speech motor systems, as well as decreased modulation of movement in later developing iambic forms. Further, components of prosodic and segmental acquisition develop independently and at different rates.
Urbanization impacts on mammals across urban-forest edges and a predictive model of edge effects.

Science.gov (United States)

Villaseñor, Nélida R; Driscoll, Don A; Escobar, Martín A H; Gibbons, Philip; Lindenmayer, David B

2014-01-01

With accelerating rates of urbanization worldwide, a better understanding of ecological processes at the wildland-urban interface is critical to conserve biodiversity. We explored the effects of high and low-density housing developments on forest-dwelling mammals. Based on habitat characteristics, we expected a gradual decline in species abundance across forest-urban edges and an increased decline rate in higher contrast edges. We surveyed arboreal mammals in sites of high and low housing density along 600 m transects that spanned urban areas and areas turn on adjacent native forest. We also surveyed forest controls to test whether edge effects extended beyond our edge transects. We fitted models describing richness, total abundance and individual species abundance. Low-density housing developments provided suitable habitat for most arboreal mammals. In contrast, high-density housing developments had lower species richness, total abundance and individual species abundance, but supported the highest abundances of an urban adapter (Trichosurus vulpecula). We did not find the predicted gradual decline in species abundance. Of four species analysed, three exhibited no response to the proximity of urban boundaries, but spilled over into adjacent urban habitat to differing extents. One species (Petaurus australis) had an extended negative response to urban boundaries, suggesting that urban development has impacts beyond 300 m into adjacent forest. Our empirical work demonstrates that high-density housing developments have negative effects on both community and species level responses, except for one urban adapter. We developed a new predictive model of edge effects based on our results and the literature. To predict animal responses across edges, our framework integrates for first time: (1) habitat quality/preference, (2) species response with the proximity to the adjacent habitat, and (3) spillover extent/sensitivity to adjacent habitat boundaries. This framework will
Effect of magnetic boundary on edge plasma profiles studied using probe measurements in EXTRAP T2R

OpenAIRE

Moustaphawi, Hawra

2012-01-01

In this Master’s thesis project, several experiments are conducted under three different conditions in order to study their effect on the edge plasma profiles. In the first case, the standard case, there is no external interference and the plasma is studied under normal lab environments. In the second case, the plasma position inside the EXTRAP T2R device is changed by a few millimeters and in the third case a magnetic boundary is inserted into the experiment. For each set of the experiment, ...
Do Persian Native Speakers Prosodically Mark Wh-in-situ Questions?

Science.gov (United States)

Shiamizadeh, Zohreh; Caspers, Johanneke; Schiller, Niels O

2018-02-01

It has been shown that prosody contributes to the contrast between declarativity and interrogativity, notably in interrogative utterances lacking lexico-syntactic features of interrogativity. Accordingly, it may be proposed that prosody plays a role in marking wh-in-situ questions in which the interrogativity feature (the wh-phrase) does not move to sentence-initial position, as, for example, in Persian. This paper examines whether prosody distinguishes Persian wh-in-situ questions from declaratives in the absence of the interrogativity feature in the sentence-initial position. To answer this question, a production experiment was designed in which wh-questions and declaratives were elicited from Persian native speakers. On the basis of the results of previous studies, we hypothesize that prosodic features mark wh-in-situ questions as opposed to declaratives at both the local (pre- and post-wh part) and global level (complete sentence). The results of the current study confirm our hypothesis that prosodic correlates mark the pre-wh part as well as the complete sentence in wh-in-situ questions. The results support theoretical concepts such as the frequency code, the universal dichotomous association between relaxation and declarativity on the one hand and tension and interrogativity on the other, the relation between prosody and pragmatics, and the relation between prosody and encoding and decoding of sentence type.

The Edge Detectors Suitable for Retinal OCT Image Segmentation

Directory of Open Access Journals (Sweden)

Su Luo

2017-01-01

Full Text Available Retinal layer thickness measurement offers important information for reliable diagnosis of retinal diseases and for the evaluation of disease development and medical treatment responses. This task critically depends on the accurate edge detection of the retinal layers in OCT images. Here, we intended to search for the most suitable edge detectors for the retinal OCT image segmentation task. The three most promising edge detection algorithms were identified in the related literature: Canny edge detector, the two-pass method, and the EdgeFlow technique. The quantitative evaluation results show that the two-pass method outperforms consistently the Canny detector and the EdgeFlow technique in delineating the retinal layer boundaries in the OCT images. In addition, the mean localization deviation metrics show that the two-pass method caused the smallest edge shifting problem. These findings suggest that the two-pass method is the best among the three algorithms for detecting retinal layer boundaries. The overall better performance of Canny and two-pass methods over EdgeFlow technique implies that the OCT images contain more intensity gradient information than texture changes along the retinal layer boundaries. The results will guide our future efforts in the quantitative analysis of retinal OCT images for the effective use of OCT technologies in the field of ophthalmology.
Cross-Linguistic Differences in Prosodic Cues to Syntactic Disambiguation in German and English

Science.gov (United States)

O'Brien, Mary Grantham; Jackson, Carrie N.; Gardner, Christine E.

2014-01-01

This study examined whether late-learning English-German second language (L2) learners and late-learning German-English L2 learners use prosodic cues to disambiguate temporarily ambiguous first language and L2 sentences during speech production. Experiments 1a and 1b showed that English-German L2 learners and German-English L2 learners used a…
Clinical Focus on Prosodic, Discursive and Pragmatic Treatment for Right Hemisphere Damaged Adults: What's Right?

Directory of Open Access Journals (Sweden)

Perrine Ferré

2011-01-01

Full Text Available Researchers and clinicians acknowledge today that the contribution of both cerebral hemispheres is necessary to a full and adequate verbal communication. Indeed, it is estimated that at least 50% of right brain damaged individuals display impairments of prosodic, discourse, pragmatics and/or lexical semantics dimensions of communication. Since the 1990's, researchers have focused on the description and the assessment of these impairments and it is only recently that authors have shown interest in planning specific intervention approaches. However, therapists in rehabilitation settings still have very few available tools. This review of recent literature demonstrates that, even though theoretical knowledge needs further methodological investigation, intervention guidelines can be identified to target right hemisphere damage communication impairments in clinical practice. These principles can be incorporated by speech and language pathologists, in a structured intervention framework, aiming at fully addressing prosodic, discursive and pragmatic components of communication.
Urbanization impacts on mammals across urban-forest edges and a predictive model of edge effects.

Directory of Open Access Journals (Sweden)

Nélida R Villaseñor

Full Text Available With accelerating rates of urbanization worldwide, a better understanding of ecological processes at the wildland-urban interface is critical to conserve biodiversity. We explored the effects of high and low-density housing developments on forest-dwelling mammals. Based on habitat characteristics, we expected a gradual decline in species abundance across forest-urban edges and an increased decline rate in higher contrast edges. We surveyed arboreal mammals in sites of high and low housing density along 600 m transects that spanned urban areas and areas turn on adjacent native forest. We also surveyed forest controls to test whether edge effects extended beyond our edge transects. We fitted models describing richness, total abundance and individual species abundance. Low-density housing developments provided suitable habitat for most arboreal mammals. In contrast, high-density housing developments had lower species richness, total abundance and individual species abundance, but supported the highest abundances of an urban adapter (Trichosurus vulpecula. We did not find the predicted gradual decline in species abundance. Of four species analysed, three exhibited no response to the proximity of urban boundaries, but spilled over into adjacent urban habitat to differing extents. One species (Petaurus australis had an extended negative response to urban boundaries, suggesting that urban development has impacts beyond 300 m into adjacent forest. Our empirical work demonstrates that high-density housing developments have negative effects on both community and species level responses, except for one urban adapter. We developed a new predictive model of edge effects based on our results and the literature. To predict animal responses across edges, our framework integrates for first time: (1 habitat quality/preference, (2 species response with the proximity to the adjacent habitat, and (3 spillover extent/sensitivity to adjacent habitat boundaries. This
Calculation of the Capture Edge in the OGMS Superconducting Separator

International Nuclear Information System (INIS)

Kozak, S.

1998-01-01

Many ferromagnetic particles, that should be deflected, are captured on the wall of an OGMS (Open Gradient Magnetic Separation) separator. This ferromagnetic material influences magnetic and hydrodynamic conditions in the separator working area. The problem how to calculate the capture edge can be defined as the search for the geometry of a nonlinear system at known boundary conditions. The boundary conditions on the capture edge are the function of the capture edge geometry. The experimental results of the separation recovery are given. The capture edge calculation has been performed by FLUX 2D and the results are presented. (author)
The "Globularization Hypothesis" of the Language-ready Brain as a Developmental Frame for Prosodic Bootstrapping Theories of Language Acquisition.

Science.gov (United States)

Irurtzun, Aritz

2015-01-01

In recent research (Boeckx and Benítez-Burraco, 2014a,b) have advanced the hypothesis that our species-specific language-ready brain should be understood as the outcome of developmental changes that occurred in our species after the split from Neanderthals-Denisovans, which resulted in a more globular braincase configuration in comparison to our closest relatives, who had elongated endocasts. According to these authors, the development of a globular brain is an essential ingredient for the language faculty and in particular, it is the centrality occupied by the thalamus in a globular brain that allows its modulatory or regulatory role, essential for syntactico-semantic computations. Their hypothesis is that the syntactico-semantic capacities arise in humans as a consequence of a process of globularization, which significantly takes place postnatally (cf. Neubauer et al., 2010). In this paper, I show that Boeckx and Benítez-Burraco's hypothesis makes an interesting developmental prediction regarding the path of language acquisition: it teases apart the onset of phonological acquisition and the onset of syntactic acquisition (the latter starting significantly later, after globularization). I argue that this hypothesis provides a developmental rationale for the prosodic bootstrapping hypothesis of language acquisition (cf. i.a. Gleitman and Wanner, 1982; Mehler et al., 1988, et seq.; Gervain and Werker, 2013), which claim that prosodic cues are employed for syntactic parsing. The literature converges in the observation that a large amount of such prosodic cues (in particular, rhythmic cues) are already acquired before the completion of the globularization phase, which paves the way for the premises of the prosodic bootstrapping hypothesis, allowing babies to have a rich knowledge of the prosody of their target language before they can start parsing the primary linguistic data syntactically.
The globularization hypothesis of the language-ready brain as a developmental frame for prosodic bootstrapping theories of language acquisition

Directory of Open Access Journals (Sweden)

Aritz eIrurtzun

2015-12-01

Full Text Available In recent research Boeckx & Benítez-Burraco (2014a,b have advanced the hypothesis that our species-specific language-ready brain should be understood as the outcome of developmental changes that occurred in our species after the split from Neanderthals-Denisovans, which resulted in a more globular braincase configuration in comparison to our closest relatives, who had elongated endocasts. According to these authors, the development of a globular brain is an essential ingredient for the language faculty and in particular, it is the centrality occupied by the thalamus in a globular brain that allows its modulatory or regulatory role, essential for syntactico-semantic computations. Their hypothesis is that the syntactico-semantic capacities arise in humans as a consequence of a process of globularization, which significantly takes place postnatally (cf. Neubauer et al. (2010. In this paper, I show that Boeckx & Benítez-Burraco’s hypothesis makes an interesting developmental prediction regarding the path of language acquisition: it teases apart the onset of phonological acquisition and the onset of syntactic acquisition (the latter starting significantly later, after globularization. I argue that this hypothesis provides a developmental rationale for the prosodic bootstrapping hypothesis of language acquisition (cf. i.a. Gleitman & Wanner (1982; Mehler et al. (1988, et seq.; Gervain & Werker (2013, which claim that prosodic cues are employed for syntactic parsing. The literature converges in the observation that a large amount of such prosodic cues (in particular, rhythmic cues are already acquired before the completion of the globularization phase, which paves the way for the premises of prosodic bootstrapping hypothesis, allowing babies to have a rich knowledge of the prosody of their target language before they can start parsing the primary linguistic data syntactically.
Simulation of Moving Trailing Edge Flaps on a Wind Turbine Blade using a Navier-Stokes based Immersed Boundary Method

DEFF Research Database (Denmark)

Behrens, Tim

. Simulations demonstrated the feasibility and robustness of the approach. The hybrid immersed boundary approach proved to be able to handle 3D airfoil sections with span-wise flap gaps. The flow around and in the wake of a deflected flap at a Reynolds number of 1.63mio was investigated for steady inflow......As the rotor diameter of wind turbines increases, turbine blades with distributed aerodynamic control surfaces promise significant load reductions. Therefore, they are coming into focus in relation to research in academia and industry. Trailing edge flaps are of particular interest in terms...... conditions. A control for two span-wise independent flaps was implemented and first load reductions could be achieved. The hybrid method has demonstrated to be a versatile tool in the research of moving trailing edge flaps. The results shall serve as the basis for future investigations of the unsteady flow...
Effects of Edge on-Site Potential in a Honeycomb Topological Magnon Insulator

Science.gov (United States)

Pantaleón, Pierre A.; Xian, Yang

2018-06-01

While the deviation of the edge on-site potential from the bulk values in a magnonic topological honeycomb lattice leads to the formation of edge states in a bearded boundary, this is not the case for a zigzag termination, where no edge state is found. In a semi-infinite lattice, the intrinsic on-site interactions along the boundary sites generate an effective defect and this gives rise to Tamm-like edge states. If a nontrivial gap is induced, both Tamm-like and topologically protected edge states appear in the band structure. The effective defect can be strengthened by an external on-site potential, and the dispersion relation, velocity and magnon density of the edge states all become tunable.
A combined prosodic and linguistic treatment approach for language-communication skills in children with autism spectrum disorders: A proof-of-concept study

Directory of Open Access Journals (Sweden)

Silva Kuschke

2016-07-01

Full Text Available This study aimed to determine whether the use of prosodically varied speech within a traditional language therapy framework had any effect on the listening skills, pragmatic skills and social interaction behaviour of three children with autism spectrum disorder (ASD. A single participant multiple baseline design across behaviours was implemented. Three participants with ASD were selected for this research. The listening skills, pragmatic skills and social interaction behaviour of the participants were compared before treatment, after a 3-week period of treatment and after a 2-week withdrawal period from treatment, utilising prosodically varied speech within a traditional language therapy approach. Statistical significance was not calculated for each individual due to the limited data, but visual inspection indicated that all the participants showed positive behavioural changes in performance across all areas after 3 weeks of treatment, independent of their pre-treatment performance level. The use of prosodically varied speech within a traditional language therapy framework appears to be a viable form of treatment for children with ASD.
Edge enhancement improves disruptive camouflage by emphasising false edges and creating pictorial relief.

Science.gov (United States)

Egan, John; Sharman, Rebecca J; Scott-Brown, Kenneth C; Lovell, Paul George

2016-12-06

Disruptive colouration is a visual camouflage composed of false edges and boundaries. Many disruptively camouflaged animals feature enhanced edges; light patches are surrounded by a lighter outline and/or a dark patches are surrounded by a darker outline. This camouflage is particularly common in amphibians, reptiles and lepidopterans. We explored the role that this pattern has in creating effective camouflage. In a visual search task utilising an ultra-large display area mimicking search tasks that might be found in nature, edge enhanced disruptive camouflage increases crypsis, even on substrates that do not provide an obvious visual match. Specifically, edge enhanced camouflage is effective on backgrounds both with and without shadows; i.e. this is not solely due to background matching of the dark edge enhancement element with the shadows. Furthermore, when the dark component of the edge enhancement is omitted the camouflage still provided better crypsis than control patterns without edge enhancement. This kind of edge enhancement improved camouflage on all background types. Lastly, we show that edge enhancement can create a perception of multiple surfaces. We conclude that edge enhancement increases the effectiveness of disruptive camouflage through mechanisms that may include the improved disruption of the object outline by implying pictorial relief.
L’unité intonative dans les textes oralisés // Intonation unit in read speech

Directory of Open Access Journals (Sweden)

Lea Tylečková

2015-12-01

Full Text Available Prosodic phrasing, i.e. division of speech into intonation units, represents a phenomenon which is central to language comprehension. Incorrect prosodic boundary markings may lead to serious misunderstandings and ambiguous interpretations of utterances. The present paper investigates prosodic competencies of Czech students of French in the domain of prosodic phrasing in French read speech. Two texts of different length are examined through a perceptual method to observe how Czech speakers of French (B1–B2 level of CEFR divide read speech into prosodic units compared to French native speakers.
South African Identities on the Edge: Lauren Beukes's Moxyland ...

African Journals Online (AJOL)

We follow the work of various critics and argue that the text presents identity as fractured, riven and characterized by sharp edges. The edges in question refer to the boundaries of personal, corporeal, national and corporate identity. These edges may be considered symptomatic of the individual and social demands placed ...
Production planning and coronal stop deletion in spontaneous speech

Directory of Open Access Journals (Sweden)

James Tanner

2017-06-01

Full Text Available Many phonological processes can be affected by segmental context spanning word boundaries, which often lead to variable outcomes. This paper tests the idea that some of this variability can be explained by reference to production planning. We examine coronal stop deletion (CSD, a variable process conditioned by preceding and upcoming phonological context, in a corpus of spontaneous British English speech, as a means of investigating a number of variables associated with planning: Prosodic boundary strength, word frequency, conditional probability of the following word, and speech rate. From the perspective of production planning, (1 prosodic boundaries should affect deletion rate independently of following context; (2 given the locality of production planning, the effect of the following context should decrease at stronger prosodic boundaries; and (3 other factors affecting planning scope should modulate the effect of upcoming phonological material above and beyond the modulating effect of prosodic boundaries. We build a statistical model of CSD realization, using pause length as a quantitative proxy for boundary strength, and find support for these predictions. These findings are compatible with the hypothesis that the locality of production planning constrains variability in speech production, and have practical implications for work on CSD and other variable processes.
A Joint Prosodic Origin of Language and Music

Directory of Open Access Journals (Sweden)

Steven Brown

2017-10-01

Full Text Available Vocal theories of the origin of language rarely make a case for the precursor functions that underlay the evolution of speech. The vocal expression of emotion is unquestionably the best candidate for such a precursor, although most evolutionary models of both language and speech ignore emotion and prosody altogether. I present here a model for a joint prosodic precursor of language and music in which ritualized group-level vocalizations served as the ancestral state. This precursor combined not only affective and intonational aspects of prosody, but also holistic and combinatorial mechanisms of phrase generation. From this common stage, there was a bifurcation to form language and music as separate, though homologous, specializations. This separation of language and music was accompanied by their (reunification in songs with words.
Effect of a serrated trailing edge on sound radiation from nearby quadrupoles.

Science.gov (United States)

Karimi, Mahmoud; Croaker, Paul; Kinns, Roger; Kessissoglou, Nicole

2017-05-01

A periodic boundary element technique is implemented to study the noise reduction capability of a plate with a serrated trailing edge under quadrupole excitation. It is assumed for this purpose that the quadrupole source tensor is independent of the trailing edge configuration and that the effect of the trailing edge shape is to modify sound radiation from prescribed boundary layer sources. The flat plate is modelled as a continuous structure with a finite repetition of small spanwise segments. The matrix equation formulated by the periodic boundary element method for this 3D acoustic scattering problem is represented as a block Toeplitz matrix. The discrete Fourier transform is employed in an iterative algorithm to solve the block Toeplitz system. The noise reduction mechanism for a serrated trailing edge in the near field is investigated by comparing contour plots obtained from each component of the quadrupole for unserrated and serrated trailing edge plate models. The noise reduction due to the serrated trailing edge is also examined as a function of the source location.
Discursive Maps at the Edge of Chaos

Science.gov (United States)

2017-05-25

Discursive Maps at the Edge of Chaos A Monograph by Major Mathieu Primeau Canadian Army, Royal Canadian Engineer School of Advanced Military...Master’s Thesis 3. DATES COVERED (From - To) JUN 2016 – MAY 2017 4. TITLE AND SUBTITLE Discursive Maps at the Edge of Chaos 5a. CONTRACT NUMBER 5b...meaning of boundaries and polarize conflict towards violence. The edge of chaos is the fine line between disorder and coherence. Discursive maps
Stability of boundary layer flow based on energy gradient theory

Science.gov (United States)

Dou, Hua-Shu; Xu, Wenqian; Khoo, Boo Cheong

2018-05-01

The flow of the laminar boundary layer on a flat plate is studied with the simulation of Navier-Stokes equations. The mechanisms of flow instability at external edge of the boundary layer and near the wall are analyzed using the energy gradient theory. The simulation results show that there is an overshoot on the velocity profile at the external edge of the boundary layer. At this overshoot, the energy gradient function is very large which results in instability according to the energy gradient theory. It is found that the transverse gradient of the total mechanical energy is responsible for the instability at the external edge of the boundary layer, which induces the entrainment of external flow into the boundary layer. Within the boundary layer, there is a maximum of the energy gradient function near the wall, which leads to intensive flow instability near the wall and contributes to the generation of turbulence.
Development of Streamwise Counter-Rotating Vortices in Flat Plate Boundary Layer Pre-set by Leading Edge Patterns

KAUST Repository

Hasheminejad, S.M.

2017-04-03

Development of streamwise counter-rotating vortices induced by leading edge patterns with different pattern shape is investigated using hot-wire anemometry in the boundary layer of a flat plate. A triangular, sinusoidal and notched patterns with the same pattern wavelength λ of 15mm and the same pattern amplitude A of 7.5mm were examined for free-stream velocity of 3m/s. The results show a good agreement with earlier studies. The inflection point on the velocity profile downstream of the trough of the patterns at the beginning of the vortex formation indicates that the vortices non-linearly propagate downstream. An additional vortex structure was also observed between the troughs of the notched pattern.
Numerical Investigation of Flow Control Feasibility with a Trailing Edge Flap

International Nuclear Information System (INIS)

Zhu, W J; Shen, W Z; Sørensen, J N

2014-01-01

This paper concerns a numerical study of employing an adaptive trailing edge flap to control the lift of an airfoil subject to unsteady inflow conditions. The periodically varying inflow is generated by two oscillating airfoils, which are located upstream of the controlled airfoil. To establish the control system, a standard PID controller is implemented in a finite volume based incompressible flow solver. An immersed boundary method is applied to treat the problem of simulating a deformable airfoil trailing edge. The flow field is solved using a 2D Reynolds averaged Navier-Stokes finite volume solver. In order to more accurately simulate wall bounded flows around the immersed boundary, a modified boundary condition is introduced in the k- ω turbulence model. As an example, turbulent flow over a NACA 64418 airfoil with a deformable trailing edge is investigated. Results from numerical simulations are convincing and may give some highlights for practical implementations of trailing edge flap to a wind turbine rotor blade

Brief Report: A Mobile Application to Treat Prosodic Deficits in Autism Spectrum Disorder and Other Communication Impairments: A Pilot Study.

Science.gov (United States)

Simmons, Elizabeth Schoen; Paul, Rhea; Shic, Frederick

2016-01-01

This study examined the acceptability of a mobile application, SpeechPrompts, designed to treat prosodic disorders in children with ASD and other communication impairments. Ten speech-language pathologists (SLPs) in public schools and 40 of their students, 5-19 years with prosody deficits participated. Students received treatment with the software over eight weeks. Pre- and post-treatment speech samples and student engagement data were collected. Feedback on the utility of the software was also obtained. SLPs implemented the software with their students in an authentic education setting. Student engagement ratings indicated students' attention to the software was maintained during treatment. Although more testing is warranted, post-treatment prosody ratings suggest that SpeechPrompts has potential to be a useful tool in the treatment of prosodic disorders.
Trailing Edge Noise Model Validation and Application to Airfoil Optimization

DEFF Research Database (Denmark)

Bertagnolio, Franck; Aagaard Madsen, Helge; Bak, Christian

2010-01-01

The aim of this article is twofold. First, an existing trailing edge noise model is validated by comparing with airfoil surface pressure fluctuations and far field sound pressure levels measured in three different experiments. The agreement is satisfactory in one case but poor in two other cases...... across the boundary layer near the trailing edge and to a lesser extent by a smaller boundary layer displacement thickness. ©2010 American Society of Mechanical Engineers...
Numerical Investigation of Flow Control Feasibility with a Trailing Edge Flap

DEFF Research Database (Denmark)

Zhu, Wei Jun; Shen, Wen Zhong; Sørensen, Jens Nørkær

2014-01-01

the control system, a standard PID controller is implemented in a finite volume based incompressible flow solver. An immersed boundary method is applied to treat the problem of simulating a deformable airfoil trailing edge. The flow field is solved using a 2D Reynolds averaged Navier-Stokes finite volume...... solver. In order to more accurately simulate wall bounded flows around the immersed boundary, a modified boundary condition is introduced in the k- ω turbulence model. As an example, turbulent flow over a NACA 64418 airfoil with a deformable trailing edge is investigated. Results from numerical...
Asymptotic theory of two-dimensional trailing-edge flows

Science.gov (United States)

Melnik, R. E.; Chow, R.

1975-01-01

Problems of laminar and turbulent viscous interaction near trailing edges of streamlined bodies are considered. Asymptotic expansions of the Navier-Stokes equations in the limit of large Reynolds numbers are used to describe the local solution near the trailing edge of cusped or nearly cusped airfoils at small angles of attack in compressible flow. A complicated inverse iterative procedure, involving finite-difference solutions of the triple-deck equations coupled with asymptotic solutions of the boundary values, is used to accurately solve the viscous interaction problem. Results are given for the correction to the boundary-layer solution for drag of a finite flat plate at zero angle of attack and for the viscous correction to the lift of an airfoil at incidence. A rational asymptotic theory is developed for treating turbulent interactions near trailing edges and is shown to lead to a multilayer structure of turbulent boundary layers. The flow over most of the boundary layer is described by a Lighthill model of inviscid rotational flow. The main features of the model are discussed and a sample solution for the skin friction is obtained and compared with the data of Schubauer and Klebanoff for a turbulent flow in a moderately large adverse pressure gradient.
Edge effects at an induced forest-grassland boundary: forest birds in ...

African Journals Online (AJOL)

Bird species diversity and guild composition between the edge (5-10 m from the margin) of primary forest abutting grassland and the deep interior (> 500 m from the margin) in the Dngoye Forest Reserve were compared. Edge and interior sites were chosen that were homogeneous with respect to habitat physiognomy i.e. ...
Applying prosodic speech features in mental health care: An exploratory study in a life-review intervention for depression

NARCIS (Netherlands)

Lamers, S.M.A.; Truong, Khiet Phuong; Steunenberg, B.; Steunenberg, B.; de Jong, Franciska M.G.; Westerhof, Gerben Johan

2014-01-01

The present study aims to investigate the application of prosodic speech features in a psychological intervention based on lifereview. Several studies have shown that speech features can be used as indicators of depression severity, but these studies are mainly based on controlled speech recording
Boundaries immersed in a scalar quantum field

International Nuclear Information System (INIS)

Actor, A.A.; Bender, I.

1996-01-01

We study the interaction between a scalar quantum field φ(x), and many different boundary configurations constructed from (parallel and orthogonal) thin planar surfaces on which φ(x) is constrained to vanish, or to satisfy Neumann conditions. For most of these boundaries the Casimir problem has not previously been investigated. We calculate the canonical and improved vacuum stress tensors left angle T μv (x) right angle and left angle direct difference μv (x) right angle of φ(x) for each example. From these we obtain the local Casimir forces on all boundary planes. For massless fields, both vacuum stress tensors yield identical attractive local Casimir forces in all Dirichlet examples considered. This desirable outcome is not a priori obvious, given the quite different features of left angle T μv (x) right angle and left angle direct difference μv (x) right angle. For Neumann conditions, left angle T μv (x) right angle and left angle direct difference μv (x) right angle lead to attractive Casimir stresses which are not always the same. We also consider Dirichlet and Neumann boundaries immersed in a common scalar quantum field, and find that these repel. The extensive catalogue of worked examples presented here belongs to a large class of completely solvable Casimir problems. Casimir forces previously unknown are predicted, among them ones which might be measurable. (orig.)
Image processing of x-ray left ventricular cineangiocardiograms and displays of cardiac functions

International Nuclear Information System (INIS)

Eiho, Shigeru; Yamada, Shigeru; Kuwahara, Michiyoshi

1980-01-01

Cineangiocardiography has been often used as one of the highly helpful techniques to examine the cardiac function. This paper deals with the method of tracing automatically the boundaries of the left ventricle on cineangiocardiograms, the method to evaluate and display various cardiac functions, the method to reconstruct the left ventricular cavity from biplane cineangiocardiograms and the method to display a 3-dimensional shape of the left ventricle reconstructed. Our algorithm of boundary tracing is based on a heuristic search for a local maximum of the changing rate in the gray level of cineangiocardiogram. The boundaries of endocardial margins of the left ventricle on 80 to 120 consecutive frames are automatically traced by our method. By using the detected boundaries of the left ventricle, a lot of quantitative information may be established on the cardiac function. The volume change, the wall motions and the %-shortening are displayed graphically. The motion of the boundary of the left ventricle is displayed on a CRT as a moving picture. The left ventricular cavity is reconstructed from the detected boundaries of the left ventricle on biplane cineangiocardiograms. A reconstructed image can be shown as superimposed lines or halftone planes to produce a 3-dimensional perspective. The %-shortening which shows the contractility of the regional myocardium is displayed on a silhouette of the left ventricle. We can easily recognize the abnormal area of contraction and the level and spread of abnormality from this displayed image. With the use of the system described in this paper, we can grasp the movement of the left ventricle exactly and evaluate the cardiac function quantitatively. (author)
Thermal Shock In Periodic Edge-Cracked Plate Supported By Elastic Foundation

OpenAIRE

Abd El-Fattah A. Rizk

2012-01-01

The study of the transient thermal stress problem for a periodic edge cracks in an elastic plate on an elastic foundations is investigated. This study may also be applied for circumferentially periodic cracked hollow cylinder under transient thermal stresses. Based on previous studies, the cylindrical shell may be modeled by a plate on an elastic foundation. The thermal stresses are generated due to sudden convective cooling on the boundary containing the edge cracks while the other boundary ...
Valley-filtered edge states and quantum valley Hall effect in gated bilayer graphene.

Science.gov (United States)

Zhang, Xu-Long; Xu, Lei; Zhang, Jun

2017-05-10

Electron edge states in gated bilayer graphene in the quantum valley Hall (QVH) effect regime can carry both charge and valley currents. We show that an interlayer potential splits the zero-energy level and opens a bulk gap, yielding counter-propagating edge modes with different valleys. A rich variety of valley current states can be obtained by tuning the applied boundary potential and lead to the QVH effect, as well as to the unbalanced QVH effect. A method to individually manipulate the edge states by the boundary potentials is proposed.
Tunable Acoustic Valley-Hall Edge States in Reconfigurable Phononic Elastic Waveguides

Science.gov (United States)

Liu, Ting-Wei; Semperlotti, Fabio

2018-01-01

We investigate the occurrence of acoustic topological edge states in a 2D phononic elastic waveguide due to a phenomenon that is the acoustic analog of the quantum valley Hall effect. We show that a topological transition takes place between two lattices having broken space-inversion symmetry due to the application of a tunable strain field. This condition leads to the formation of gapless edge states at the domain walls, as further illustrated by the analysis of the bulk-edge correspondence and of the associated topological invariants. Interestingly, topological edge states can also be triggered at the boundary of a single domain, when boundary conditions are properly selected. We also show that the static modulation of the strain field allows us to tune the response of the material between the different supported edge states. Although time-reversal symmetry is still intact in this material system, the edge states are topologically protected when intervalley mixing is either weak or negligible. This characteristic enables selective valley injection, which is achieved via synchronized source strategy.
Bragg-edge neutron transmission strain tomography for in situ loadings

Energy Technology Data Exchange (ETDEWEB)

Wensrich, C.M., E-mail: christopher.wensrich@newcastle.edu.au [School of Engineering, The University of Newcastle, Callaghan, NSW 2308 (Australia); Hendriks, J.N.; Gregg, A. [School of Engineering, The University of Newcastle, Callaghan, NSW 2308 (Australia); Meylan, M.H. [School of Mathematical and Physical Sciences, The University of Newcastle, Callaghan, NSW 2308 (Australia); Luzin, V. [Bragg Institute, Australian Nuclear Science and Technology Organisation (ANSTO), Kirrawee, NSW 2232 (Australia); Tremsin, A.S. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)

2016-09-15

An approach for tomographic reconstruction of three-dimensional strain distributions from Bragg-edge neutron transmission strain images is outlined and investigated. This algorithm is based on the link between Bragg-edge strain measurements and the Longitudinal Ray Transform, which has been shown to be sensitive only to boundary displacement. By exploiting this observation we provide a method for reconstructing boundary displacement from sets of Bragg-edge strain images. In the case where these displacements are strictly the result of externally applied tractions, corresponding internal strain fields can then be found through traditional linear-static finite element methods. This approach is tested on synthetic data in two-dimensions, where the rate of convergence in the presence of measurement noise and beam attenuation is examined.
Communicative dynamism and prosodic prominence in presentation sentences with initial rhematic subjects

Directory of Open Access Journals (Sweden)

Martin Adam

2017-08-01

Full Text Available Within the framework of the theory of functional sentence perspective (Firbas 1992, the distinction between presentation and quality scale sentences plays a vital role. The present paper proposes to shed light on one of the most common configurations of presentation sentences, viz. structures with initial rhematic subject (e.g. an uninvited dwarf came, examining the way native speakers place the intonation centre in such structures, i.e. to map the correspondence between the degrees of communicative dynamism and prosodic prominence. For the purpose of the investigation selected chapters from Tolkien’s The Hobbit are used.
Swords with Blunt Edges

Science.gov (United States)

Popham, W. James

2004-01-01

Many U.S. educators now wonder whether they're teachers or targets. This mentality stems from the specter of their school being sanctioned for failing the state accountability tests mandated under No Child Left Behind (NCLB). According to this author, most of those tests are like blunt-edged swords: They function badly in two directions. While…
Ground observations of magnetospheric boundary layer phenomena

International Nuclear Information System (INIS)

McHenry, M.A.; Clauer, C.R.; Friis-Christensen, E.; Newell, P.T.; Kelly, J.D.

1990-01-01

Several classes of traveling vortices in the dayside ionospheric convection have been detected and tracked using the Greenland magnetometer chain (Friis-Christensen et al., 1988, McHenry et al., 1989). One class observed during quiet times consists of a continuous series of vortices moving generally anti-sunward for several hours at a time. The vortices strength is seen to be approximately steady and neighboring vortices rotate in opposite directions. Sondrestrom radar observations show that the vortices are located at the ionospheric convection reversal boundary. Low altitude DMSP observations indicate the vortices are on field lines which map to the inner edge of the low latitude boundary layer. Because the vortices are conjugate to the boundary layer, repeat in a regular fashion and travel antisunward, the authors argue that this class of vortices is caused by the Kelvin-Helmholtz instability of the inner edge of the magnetospheric boundary layer
Quantization of edge currents for continuous magnetic operators

CERN Document Server

Kellendonk, J

2003-01-01

For a magnetic Hamiltonian on a half-plane given as the sum of the Landau operator with Dirichlet boundary conditions and a random potential, a quantization theorem for the edge currents is proven. This shows that the concept of edge channels also makes sense in presence of disorder. Moreover, gaussian bounds on the heat kernel and its covariant derivatives are obtained.
Parametric boundary reconstruction algorithm for industrial CT metrology application.

Science.gov (United States)

Yin, Zhye; Khare, Kedar; De Man, Bruno

2009-01-01

High-energy X-ray computed tomography (CT) systems have been recently used to produce high-resolution images in various nondestructive testing and evaluation (NDT/NDE) applications. The accuracy of the dimensional information extracted from CT images is rapidly approaching the accuracy achieved with a coordinate measuring machine (CMM), the conventional approach to acquire the metrology information directly. On the other hand, CT systems generate the sinogram which is transformed mathematically to the pixel-based images. The dimensional information of the scanned object is extracted later by performing edge detection on reconstructed CT images. The dimensional accuracy of this approach is limited by the grid size of the pixel-based representation of CT images since the edge detection is performed on the pixel grid. Moreover, reconstructed CT images usually display various artifacts due to the underlying physical process and resulting object boundaries from the edge detection fail to represent the true boundaries of the scanned object. In this paper, a novel algorithm to reconstruct the boundaries of an object with uniform material composition and uniform density is presented. There are three major benefits in the proposed approach. First, since the boundary parameters are reconstructed instead of image pixels, the complexity of the reconstruction algorithm is significantly reduced. The iterative approach, which can be computationally intensive, will be practical with the parametric boundary reconstruction. Second, the object of interest in metrology can be represented more directly and accurately by the boundary parameters instead of the image pixels. By eliminating the extra edge detection step, the overall dimensional accuracy and process time can be improved. Third, since the parametric reconstruction approach shares the boundary representation with other conventional metrology modalities such as CMM, boundary information from other modalities can be directly
Transaortic edge-to-edge mitral valve repair for moderate secondary/functional mitral regurgitation in patients undergoing aortic root/valve intervention.

Science.gov (United States)

Choudhary, Shiv Kumar; Abraham, Atul; Bhoje, Amol; Gharde, Parag; Sahu, Manoj; Talwar, Sachin; Airan, Balram

2017-11-01

The present study evaluates the feasibility, safety, and efficacy of edge-to-edge repair for moderate secondary/functional mitral regurgitation in patients undergoing aortic valve/root interventions. Sixteen patients underwent transaortic edge-to-edge mitral valve repair. Mitral regurgitation was 2+ in 8 patients and 3+ in 6 patients. Two patients in whom cardiac arrest developed preoperatively had severe (4+) mitral regurgitation. Patients underwent operation for severe aortic regurgitation ± aortic root lesions. The mean left ventricular systolic and diastolic diameters were 51.5 ± 12.8 mm and 70.7 ± 10.7 mm, respectively. Left ventricular ejection fraction ranged from 20% to 60%. Primary surgical procedure included Bentall's ± hemiarch replacement in 10 patients, aortic valve replacement in 5 patients, and noncoronary sinus replacement with aortic valve repair in 1 patient. Severity of mitral regurgitation decreased to trivial or zero in 13 patients, 1+ in 2 patients, and 2+ in 1 patient. There were no gradients across the mitral valve in 9 patients, less than 5 mm Hg in 6 patients, and 9 mm Hg in 1 patient. There was no operative mortality. Follow-up ranged from 2 weeks to 54 months. Echocardiography showed trivial or no mitral regurgitation in 12 patients, 1+ in 2 patients, and 2+ in 2 patients. None of the patients had significant mitral stenosis. The mean left ventricular systolic and diastolic diameters decreased to 40.5 ± 10.3 mm and 58.7 ± 11.6 mm, respectively. Ejection fraction also improved slightly (22%-65%). Transaortic edge-to-edge mitral valve repair is a safe and effective technique to abolish secondary/functional mitral regurgitation. However, its impact on overall survival needs to be studied. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.
Long coherence times for edge spins

Science.gov (United States)

Kemp, Jack; Yao, Norman Y.; Laumann, Christopher R.; Fendley, Paul

2017-06-01

We show that in certain one-dimensional spin chains with open boundary conditions, the edge spins retain memory of their initial state for very long times, even at infinite temperature. The long coherence times do not require disorder, only an ordered phase. In the integrable Ising and XYZ chains, the presence of a strong zero mode means the coherence time is infinite. When Ising is perturbed by interactions breaking the integrability, the coherence time remains exponentially long in the perturbing couplings. We show that this is a consequence of an edge ‘almost’ strong zero mode that almost commutes with the Hamiltonian. We compute this operator explicitly, allowing us to estimate accurately the plateau value of edge spin autocorrelator.
Edge effects in composites

International Nuclear Information System (INIS)

Guz, A.N.; Kokhanenko, Yu.V.

1995-01-01

In the present article we survey papers on edge effects investigated by the rigorous approach. We interpret edge effects as stressed states created in a composite as a result of zones in which the stresses exhibit a rapidly changing behavior in comparison with the slow variation of the stresses outside such zones. Here the range of the edge effect is defined as the distance from the point of its inception to the boundary of the edge zone in a given direction. The transition of the stresses to the slowly varying state is determined within prescribed error limits. The size and configuration of the edge zone depends on the tolerated error. Clearly, the main difficulty associated with the rigorous approach is finding solutions of the elasticity problems. The finite-difference approach is suggested for the approximate solution of these problems. In light of the comparative time consumption of the finite-difference approach, it is best directed at certain classes of problems rather than at particular individual problems. Not too many papers on the investigation of edge effects by the rigorous approach have been published to date. Below, following in their footsteps, we formulate edge effect problems in composites, determine classes of problems, and investigate edge effects in composite materials and structural elements using them in Cartesian (planar and three-dimensional problems) and cylindrical (axisymmetric problems) coordinate frames. We note that the division of approaches to the study of edge effects into qualitative (nonrigorous) and quantitative (rigorous) reflects the authors own point of view. Of course, other schemes of classification of the approaches to the investigation of the regions of rapidly varying states in composites are possible

Low scatter edge blackening compounds for refractive optical elements

International Nuclear Information System (INIS)

Lewis, I.T.; Telkamp, A.R.; Ledebuhr, A.G.

1989-01-01

This paper reports on low scatter edge blackening compounds for refractive optical elements. Perkin-Elmer's Applied Optics Operation recently delivered several prototype wide-field-of-view (WFOV), F/2.8, 250 mm efl, near diffraction limited, concentric lenses toLawrence Livermore National Laboratory (LLNL). In these lenses, special attention was paid to reducing stray light to allow viewing of very dim objects. Because of the very large FOV, the use of a long baffle to eliminate direct illumination of lens edges was not practical. With the existing relatively short baffle design, one-bounce stray light paths off the element edges are possible. The scattering off the inside edges thus had to be kept to an absolute minimum. While common means for blackening the edges of optical elements are easy to apply and quite cost effective for normal lens assemblies, their blackening effect is limited by the Fresnel reflection due to the index of refraction mismatch at the glass boundary. At high angles of incidence, total internal reflection (TIR) might occur ruining the effect of the blackening process. An index-match absorbing medium applied to the edges of such elements is the most effective approach for reducing the amount of undesired light reflection or scattered off these edges. The presence of such a medium provides an extended path outside the glass boundary in which an absorptive non-scattering dye can be used to eliminate light that might otherwise have propagated to the focal plane
A model for managing edge effects in harvest scheduling using spatial optimization

Science.gov (United States)

Kai L. Ross; Sándor F. Tóth

2016-01-01

Actively managed forest stands can create new forest edges. If left unchecked over time and across space, forest operations such as clear-cuts can create complex networks of forest edges. Newly created edges alter the landscape and can affect many environmental factors. These altered environmental factors have a variety of impacts on forest growth and structure and can...
Streamwise counter-rotating vortices generated by triangular leading edge pattern in flat plate boundary layer

KAUST Repository

Hasheminejad, S. M.

2016-01-05

A series of flow visualizations were conducted to qualitatively study the development of streamwise counter-rotating vortices over a flat plate induced by triangular patterns at the leading edge of a flat plate. The experiments were carried out for a Reynolds number based on the pattern wavelength (λ) of 3080. The results depict the onset, development and breakdown of the vortical structures within the flat plate boundary layer. Moreover, the effect of one spanwise array of holes with diameter of 0.2λ (=3 mm) was examined. This investigation was done on two different flat plates with holes placed at the location x/λ = 2 downstream of the troughs and peaks. The presence of holes after troughs does not show any significant effect on the vortical structures. However, the plate with holes after peaks noticeably delays the vortex breakdown. In this case, the “mushroom-like” vortices move away from the wall and propagate downstream with stable vortical structures. The vortex growth is halted further downstream but start to tilt aside.
Heat Transfer and Friction Studies in a Tilted and Rib-Roughened Trailing-Edge Cooling Cavity with and without the Trailing-Edge Cooling Holes

Directory of Open Access Journals (Sweden)

M. E. Taslim

2014-01-01

Full Text Available Local and average heat transfer coefficients and friction factors were measured in a test section simulating the trailing-edge cooling cavity of a turbine airfoil. The test rig with a trapezoidal cross-sectional area was rib-roughened on two opposite sides of the trapezoid (airfoil pressure and suction sides with tapered ribs to conform to the cooling cavity shape and had a 22-degree tilt in the flow direction upstream of the ribs that affected the heat transfer coefficients on the two rib-roughened surfaces. The radial cooling flow traveled from the airfoil root to the tip while exiting through 22 cooling holes along the airfoil trailing-edge. Two rib geometries, with and without the presence of the trailing-edge cooling holes, were examined. The numerical model contained the entire trailing-edge channel, ribs, and trailing-edge cooling holes to simulate exactly the tested geometry. A pressure-correction based, multiblock, multigrid, unstructured/adaptive commercial software was used in this investigation. Realizable k-ε turbulence model in conjunction with enhanced wall treatment approach for the near wall regions was used for turbulence closure. The applied thermal boundary conditions to the CFD models matched the test boundary conditions. Comparisons are made between the experimental and numerical results.
Impurity production and transport in the boundary layer of tokamaks

International Nuclear Information System (INIS)

McCracken, G.M.

1987-01-01

The processes by which impurities are produced and enter the discharge are discussed. Emphasis is placed on sputtering at the limiter and an analytical global model is described which incorporates the self-stabilizing effects whch control the edge temperature. Predictions of the scaling of edge temperature and of total radiated power are compared with experimental data from JET and other tokamaks operating with limiters. Under many conditions the scaling of the edge conditions and of the radiated power is accurately predicted. Impurity transport in the boundary and the question of how to control the boundary layer is then discussed. The example of the Impurity Control Limiter on DITE is described. (author)
Edge currents in frustrated Josephson junction ladders

Science.gov (United States)

Marques, A. M.; Santos, F. D. R.; Dias, R. G.

2016-09-01

We present a numerical study of quasi-1D frustrated Josephson junction ladders with diagonal couplings and open boundary conditions, in the large capacitance limit. We derive a correspondence between the energy of this Josephson junction ladder and the expectation value of the Hamiltonian of an analogous tight-binding model, and show how the overall superconducting state of the chain is equivalent to the minimum energy state of the tight-binding model in the subspace of one-particle states with uniform density. To satisfy the constraint of uniform density, the superconducting state of the ladder is written as a linear combination of the allowed k-states of the tight-binding model with open boundaries. Above a critical value of the parameter t (ratio between the intra-rung and inter-rung Josephson couplings) the ladder spontaneously develops currents at the edges, which spread to the bulk as t is increased until complete coverage is reached. Above a certain value of t, which varies with ladder size (t = 1 for an infinite-sized ladder), the edge currents are destroyed. The value t = 1 corresponds, in the tight-binding model, to the opening of a gap between two bands. We argue that the disappearance of the edge currents with this gap opening is not coincidental, and that this points to a topological origin for these edge current states.
Hierarquia prosódica e hierarquia melódica na canção Gabriela Prosodic hierarchy and melodic hierarchy in Gabriela

Directory of Open Access Journals (Sweden)

José Roberto do Carmo Jr

2010-01-01

Full Text Available O presente artigo propõe uma investigação das relações de interface entre o componente linguístico - prosódico - e o componente musical na palavra cantada. Tomando como objeto a canção Gabriela, de Tom Jobim, investigamos as relações que se estabelecem entre a hierarquia prosódica (Nespor & Vogel, 1986 e a hierarquia melódica (Carmo Jr 2007. Mostramos que no caso de incompatibilidade entre a estrutura prosódica e melódica, os processos fonológicos do português brasileiro de elisão, degeminação, ditongação e retração acentual podem violar seus domínios prosódicos de aplicação, mas ainda assim são organizados de acordo com os domínios melódicos.In this article we investigate the relation between the linguistic (prosodic component and the musical grammar in lyrics. Specifically, by analyzing Gabriela, by Tom Jobim, we discuss the relation between the Prosodic Hierarchy (Nespor & Vogel 1986 and the Melodic Hierarchy (Carmo Jr 2007. We show that when there is a mismatch between these two hierarchies, the phonological processes of elision, degemination, dipthongation and stress retraction in Brazilian Portuguese may not comply with the prosodic domain for their application, while still satisfying the restrictions related to the melodic domains.
Brief Report: A Mobile Application to Treat Prosodic Deficits in Autism Spectrum Disorder and Other Communication Impairments: A Pilot Study

Science.gov (United States)

Simmons, Elizabeth Schoen; Paul, Rhea; Shic, Frederick

2016-01-01

This study examined the acceptability of a mobile application, "SpeechPrompts," designed to treat prosodic disorders in children with ASD and other communication impairments. Ten speech-language pathologists (SLPs) in public schools and 40 of their students, 5-19 years with prosody deficits participated. Students received treatment with…
Effect of explicit teaching of prosodic features on the development of listening comprehension by Farsi-English interpreter trainees : An experimental study

NARCIS (Netherlands)

Yenkimaleki, M.; Vincent, van Heuven J.

2016-01-01

This study investigates the effect of explicit teaching of prosodic features on developing listening comprehension by interpreter trainees. Two groups of student interpreters were formed. All were native speakers of Farsi who studied English translation and interpreting at the BA level at the State
High-confinement-mode edge stability of Alcator C-mod plasmas

International Nuclear Information System (INIS)

Mossessian, D.A.; Snyder, P.; Hubbard, A.; Hughes, J.W.; Greenwald, M.; La Bombard, B.; Snipes, J.A.; Wolfe, S.; Wilson, H.

2003-01-01

For steady state high-confinement-mode (H-mode) operation, a relaxation mechanism is required to limit build-up of the edge gradient and impurity content. Alcator C-Mod [Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] sees two such mechanisms--EDA (enhanced D-alpha H mode) and grassy ELMs (edge localized modes), but not large type I ELMs. In EDA the edge relaxation is provided by an edge localized quasicoherent (QC) electromagnetic mode that exists at moderate pedestal temperature T 95 >3.5, and does not limit the buildup of the edge pressure gradient. The q boundary of the operational space of the mode depends on plasma shape, with the q 95 limit moving down with increasing plasma triangularity. At high edge pressure gradients and temperatures the mode is replaced by broadband fluctuations ( f<50 kHz) and small irregular ELMs are observed. Ideal MHD (magnetohydrodynamic) stability analysis that includes both pressure and current driven edge modes shows that the discharges where the QC mode is observed are stable. The ELMs are identified as medium n (10< n<50) coupled peeling/ballooning modes. The predicted stability boundary of the modes as a function of pedestal current and pressure gradient is reproduced in experimental observations. The measured dependence of the ELMs' threshold and amplitude on plasma triangularity is consistent with the results of ideal MHD analysis performed with the linear stability code ELITE [Wilson et al., Phys. Plasmas 9, 1277 (2002)
Edge detection in landing budgerigars (Melopsittacus undulatus.

Directory of Open Access Journals (Sweden)

Partha Bhagavatula

Full Text Available BACKGROUND: While considerable scientific effort has been devoted to studying how birds navigate over long distances, relatively little is known about how targets are detected, obstacles are avoided and smooth landings are orchestrated. Here we examine how visual features in the environment, such as contrasting edges, determine where a bird will land. METHODOLOGY/PRINCIPAL FINDINGS: Landing in budgerigars (Melopsittacus undulatus was investigated by training them to fly from a perch to a feeder, and video-filming their landings. The feeder was placed on a grey disc that produced a contrasting edge against a uniformly blue background. We found that the birds tended to land primarily at the edge of the disc and walk to the feeder, even though the feeder was in the middle of the disc. This suggests that the birds were using the visual contrast at the boundary of the disc to target their landings. When the grey level of the disc was varied systematically, whilst keeping the blue background constant, there was one intermediate grey level at which the budgerigar's preference for the disc boundary disappeared. The budgerigars then landed randomly all over the test surface. Even though this disc is (for humans clearly distinguishable from the blue background, it offers very little contrast against the background, in the red and green regions of the spectrum. CONCLUSIONS: We conclude that budgerigars use visual edges to target and guide landings. Calculations of photoreceptor excitation reveal that edge detection in landing budgerigars is performed by a color-blind luminance channel that sums the signals from the red and green photoreceptors, or, alternatively, receives input from the red double-cones. This finding has close parallels to vision in honeybees and primates, where edge detection and motion perception are also largely color-blind.
Magnetic X-points, edge localized modes, and stochasticity

International Nuclear Information System (INIS)

Sugiyama, L. E.; Strauss, H. R.

2010-01-01

Edge localized modes (ELMs) near the boundary of a high temperature, magnetically confined toroidal plasma represent a new type of nonlinear magnetohydrodynamic (MHD) plasma instability that grows through a coherent plasma interaction with part of a chaotic magnetic field. Under perturbation, the freely moving magnetic boundary surface with an X-point splits into two different limiting asymptotic surfaces (manifolds), similar to the behavior of a hyperbolic saddle point in Hamiltonian dynamics. Numerical simulation using the extended MHD code M3D shows that field-aligned plasma instabilities, such as ballooning modes, can couple to the ''unstable'' manifold that forms helical, field-following lobes around the original surface. Large type I ELMs proceed in stages. Initially, a rapidly growing ballooning outburst involves the entire outboard side. Large plasma fingers grow well off the midplane, while low density regions penetrate deeply into the plasma. The magnetic field becomes superficially stochastic. A secondary inboard edge instability causes inboard plasma loss. The plasma gradually relaxes back toward axisymmetry, with diminishing cycles of edge instability. Poloidal rotation of the interior and edge plasma may be driven. The magnetic tangle constrains the early nonlinear ballooning, but may encourage the later inward penetration. Equilibrium toroidal rotation and two-fluid diamagnetic drifts have relatively small effects on a strong MHD instability. Intrinsic magnetic stochasticity may help explain the wide range of experimentally observed ELMs and ELM-free behavior in fusion plasmas, as well as properties of the H-mode and plasma edge.
Expansion of Prosodic Abilities at the Transition From Babble to Words: A Comparison Between Children With Cochlear Implants and Normally Hearing Children.

Science.gov (United States)

Pettinato, Michèle; Clerck, Ilke De; Verhoeven, Jo; Gillis, Steven

This longitudinal study examined the effect of emerging vocabulary production on the ability to produce the phonetic cues to prosodic prominence in babbled and lexical disyllables of infants with cochlear implants (CI) and normally hearing (NH) infants. Current research on typical language acquisition emphasizes the importance of vocabulary development for phonological and phonetic acquisition. Children with CI experience significant difficulties with the perception and production of prosody, and the role of possible top-down effects is, therefore, particularly relevant for this population. Isolated disyllabic babble and first words were identified and segmented in longitudinal audio-video recordings and transcriptions for nine NH infants and nine infants with CI interacting with their parents. Monthly recordings were included from the onset of babbling until children had reached a cumulative vocabulary of 200 words. Three cues to prosodic prominence, fundamental frequency (f0), intensity, and duration, were measured in the vocalic portions of stand-alone disyllables. To represent the degree of prosodic differentiation between two syllables in an utterance, the raw values for intensity and duration were transformed to ratios, and for f0, a measure of the perceptual distance in semitones was derived. The degree of prosodic differentiation for disyllabic babble and words for each cue was compared between groups. In addition, group and individual tendencies on the types of stress patterns for babble and words were also examined. The CI group had overall smaller pitch and intensity distances than the NH group. For the NH group, words had greater pitch and intensity distances than babbled disyllables. Especially for pitch distance, this was accompanied by a shift toward a more clearly expressed stress pattern that reflected the influence of the ambient language. For the CI group, the same expansion in words did not take place for pitch. For intensity, the CI group gave
Edge detection based on computational ghost imaging with structured illuminations

Science.gov (United States)

Yuan, Sheng; Xiang, Dong; Liu, Xuemei; Zhou, Xin; Bing, Pibin

2018-03-01

Edge detection is one of the most important tools to recognize the features of an object. In this paper, we propose an optical edge detection method based on computational ghost imaging (CGI) with structured illuminations which are generated by an interference system. The structured intensity patterns are designed to make the edge of an object be directly imaged from detected data in CGI. This edge detection method can extract the boundaries for both binary and grayscale objects in any direction at one time. We also numerically test the influence of distance deviations in the interference system on edge extraction, i.e., the tolerance of the optical edge detection system to distance deviation. Hopefully, it may provide a guideline for scholars to build an experimental system.
X-point effect on edge stability

International Nuclear Information System (INIS)

Saarelma, S; Kirk, A; Kwon, O J

2011-01-01

We study the effects of the X-point configuration on edge localized mode (ELM) triggering peeling and ballooning modes using fixed boundary equilibria and modifying the plasma shape to approach the limit of a true X-point. The current driven pure peeling modes are asymptotically stabilized by the X-point while the stabilizing effect on ballooning modes depends on the poloidal location of the X-point. The coupled peeling-ballooning modes experience the elimination of the peeling component as the X-point is introduced. This can significantly affect the edge stability diagrams used to analyse the ELM triggering mechanisms.
A new boundary control scheme for simultaneous achievement of H-mode and radiative cooling (SHC boundary)

International Nuclear Information System (INIS)

Ohyabu, N.

1995-05-01

We have proposed a new boundary control scheme (SHC boundary), which could allow simultaneous achievement of the H-mode type confinement improvement and radiative cooling with wide heat flux distribution. In our proposed configuration, a low m island layer sharply separates a plasma confining region from an open 'ergodic' boundary. The degree of openness in the ergodic boundary must be high enough to make the plasma pressure constant along the field line, which in turn separates low density plasma just outside the plasma confining region (the key external condition for achieving a good H-mode discharge) from very high density, cold radiative plasma near the wall (required for effective edge radiative cooling). Examples of such proposed SHC boundaries for Heliotron typed devices and tokamaks are presented. (author)
Oscillations of a Turbulent Jet Incident Upon an Edge

Energy Technology Data Exchange (ETDEWEB)

J.C. Lin; D. Rockwell

2000-09-19

For the case of a jet originating from a fully turbulent channel flow and impinging upon a sharp edge, the possible onset and nature of coherent oscillations has remained unexplored. In this investigation, high-image-density particle image velocimetry and surface pressure measurements are employed to determine the instantaneous, whole-field characteristics of the turbulent jet-edge interaction in relation to the loading of the edge. It is demonstrated that even in absence of acoustic resonant or fluid-elastic effects, highly coherent, self-sustained oscillations rapidly emerge above the turbulent background. Two clearly identifiable modes of instability are evident. These modes involve large-scale vortices that are phase-locked to the gross undulations of the jet and its interaction with the edge, and small-scale vortices, which are not phase-locked. Time-resolved imaging of instantaneous vorticity and velocity reveals the form, orientation, and strength of the large-scale concentrations of vorticity approaching the edge in relation to rapid agglomeration of small-scale vorticity concentrations. Such vorticity field-edge interactions exhibit rich complexity, relative to the simplified pattern of vortex-edge interaction traditionally employed for the quasi-laminar edgetone. Furthermore, these interactions yield highly nonlinear surface pressure signatures. The origin of this nonlinearity, involving coexistence of multiple frequency components, is interpreted in terms of large- and small-scale vortices embedded in distributed vorticity layers at the edge. Eruption of the surface boundary layer on the edge due to passage of the large-scale vortex does not occur; rather apparent secondary vorticity concentrations are simply due to distension of the oppositely-signed vorticity layer at the tip of the edge. The ensemble-averaged turbulent statistics of the jet quickly take on an identity that is distinct from the statistics of the turbulent boundary layer in the channel
Effects of cognitive impairment on prosodic parameters of speech production planning in multiple sclerosis.

Science.gov (United States)

De Looze, Céline; Moreau, Noémie; Renié, Laurent; Kelly, Finnian; Ghio, Alain; Rico, Audrey; Audoin, Bertrand; Viallet, François; Pelletier, Jean; Petrone, Caterina

2017-05-24

Cognitive impairment (CI) affects 40-65% of patients with multiple sclerosis (MS). CI can have a negative impact on a patient's everyday activities, such as engaging in conversations. Speech production planning ability is crucial for successful verbal interactions and thus for preserving social and occupational skills. This study investigates the effect of cognitive-linguistic demand and CI on speech production planning in MS, as reflected in speech prosody. A secondary aim is to explore the clinical potential of prosodic features for the prediction of an individual's cognitive status in MS. A total of 45 subjects, that is 22 healthy controls (HC) and 23 patients in early stages of relapsing-remitting MS, underwent neuropsychological tests probing specific cognitive processes involved in speech production planning. All subjects also performed a read speech task, in which they had to read isolated sentences manipulated as for phonological length. Results show that the speech of MS patients with CI is mainly affected at the temporal level (articulation and speech rate, pause duration). Regression analyses further indicate that rate measures are correlated with working memory scores. In addition, linear discriminant analysis shows the ROC AUC of identifying MS patients with CI is 0.70 (95% confidence interval: 0.68-0.73). Our findings indicate that prosodic planning is deficient in patients with MS-CI and that the scope of planning depends on patients' cognitive abilities. We discuss how speech-based approaches could be used as an ecological method for the assessment and monitoring of CI in MS. © 2017 The British Psychological Society.
The Influence of Prosodic Input in the Second Language Classroom: Does It Stimulate Child Acquisition of Word Order and Function Words?

Science.gov (United States)

Campfield, Dorota E.; Murphy, Victoria A.

2017-01-01

This paper reports on an intervention study with young Polish beginners (mean age: 8 years, 3 months) learning English at school. It seeks to identify whether exposure to rhythmic input improves knowledge of word order and function words. The "prosodic bootstrapping hypothesis", relevant in developmental psycholinguistics, provided the…
Structure and motion of junctions between coherent and incoherent twin boundaries in copper

Energy Technology Data Exchange (ETDEWEB)

Brown, J.A. [Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095 (United States); Ghoniem, N.M., E-mail: ghoniem@ucla.edu [Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095 (United States)

2009-09-15

The atomic mechanisms of twin boundary migration in copper under externally applied mechanical loads and during thermal annealing are investigated utilizing molecular dynamics computer simulations. The migration dynamics of the incoherent {Sigma}=3[110](112) twin boundary (ITB), pinned between two {Sigma}=3[110](111) twin boundaries, is determined. A three-dimensional structural model is described for the junction between intersecting coherent and incoherent twin boundaries, and migration velocities are calculated under thermal annealing conditions. It is shown that the coherent twin boundary (CTB)/ITB junction results in breaking the crystal symmetry by creation of either an edge dislocation or a mixed (edge/screw) at the intersection. These two types of defects can lead to pronounced differences in the observed migration (and hence annealing) rates of ICT/CTB junctions. The annealing rate resulting from the migration of ITBs with a mixed dislocation is found to be more than twice that of the edge dislocation. The mechanism of ITB motion is shown to be governed by successive kink-like motion of neighboring atomic columns, each of which is shifted by 1/4[1 1 0], followed by structural relaxation to accommodate boundary motion.

Structure and motion of junctions between coherent and incoherent twin boundaries in copper

International Nuclear Information System (INIS)

Brown, J.A.; Ghoniem, N.M.

2009-01-01

The atomic mechanisms of twin boundary migration in copper under externally applied mechanical loads and during thermal annealing are investigated utilizing molecular dynamics computer simulations. The migration dynamics of the incoherent Σ=3[110](112) twin boundary (ITB), pinned between two Σ=3[110](111) twin boundaries, is determined. A three-dimensional structural model is described for the junction between intersecting coherent and incoherent twin boundaries, and migration velocities are calculated under thermal annealing conditions. It is shown that the coherent twin boundary (CTB)/ITB junction results in breaking the crystal symmetry by creation of either an edge dislocation or a mixed (edge/screw) at the intersection. These two types of defects can lead to pronounced differences in the observed migration (and hence annealing) rates of ICT/CTB junctions. The annealing rate resulting from the migration of ITBs with a mixed dislocation is found to be more than twice that of the edge dislocation. The mechanism of ITB motion is shown to be governed by successive kink-like motion of neighboring atomic columns, each of which is shifted by 1/4[1 1 0], followed by structural relaxation to accommodate boundary motion.
From prosodic structure to acoustic saliency: A fMRI investigation of speech rate, clarity, and emphasis

Science.gov (United States)

Golfinopoulos, Elisa

Acoustic variability in fluent speech can arise at many stages in speech production planning and execution. For example, at the phonological encoding stage, the grouping of phonemes into syllables determines which segments are coarticulated and, by consequence, segment-level acoustic variation. Likewise phonetic encoding, which determines the spatiotemporal extent of articulatory gestures, will affect the acoustic detail of segments. Functional magnetic resonance imaging (fMRI) was used to measure brain activity of fluent adult speakers in four speaking conditions: fast, normal, clear, and emphatic (or stressed) speech. These speech manner changes typically result in acoustic variations that do not change the lexical or semantic identity of productions but do affect the acoustic saliency of phonemes, syllables and/or words. Acoustic responses recorded inside the scanner were assessed quantitatively using eight acoustic measures and sentence duration was used as a covariate of non-interest in the neuroimaging analysis. Compared to normal speech, emphatic speech was characterized acoustically by a greater difference between stressed and unstressed vowels in intensity, duration, and fundamental frequency, and neurally by increased activity in right middle premotor cortex and supplementary motor area, and bilateral primary sensorimotor cortex. These findings are consistent with right-lateralized motor planning of prosodic variation in emphatic speech. Clear speech involved an increase in average vowel and sentence durations and average vowel spacing, along with increased activity in left middle premotor cortex and bilateral primary sensorimotor cortex. These findings are consistent with an increased reliance on feedforward control, resulting in hyper-articulation, under clear as compared to normal speech. Fast speech was characterized acoustically by reduced sentence duration and average vowel spacing, and neurally by increased activity in left anterior frontal
The effect of small streamwise velocity distortion on the boundary layer flow over a thin flat plate with application to boundary layer stability theory

Science.gov (United States)

Goldstein, M. E.; Leib, S. J.; Cowley, S. J.

1990-01-01

Researchers show how an initially linear spanwise disturbance in the free stream velocity field is amplified by leading edge bluntness effects and ultimately leads to a small amplitude but linear spanwise motion far downstream from the edge. This spanwise motion is imposed on the boundary layer flow and ultimately causes an order-one change in its profile shape. The modified profiles are highly unstable and can support Tollmein-Schlichting wave growth well upstream of the theoretical lower branch of the neutral stability curve for a Blasius boundary layer.
Boundary Plasma Turbulence Simulations for Tokamaks

International Nuclear Information System (INIS)

Xu, X.; Umansky, M.; Dudson, B.; Snyder, P.

2008-05-01

The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T e ; T i ) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics
Unified bulk-boundary correspondence for band insulators

Science.gov (United States)

Rhim, Jun-Won; Bardarson, Jens H.; Slager, Robert-Jan

2018-03-01

The bulk-boundary correspondence, a topic of intensive research interest over the past decades, is one of the quintessential ideas in the physics of topological quantum matter. Nevertheless, it has not been proven in all generality and has in certain scenarios even been shown to fail, depending on the boundary profiles of the terminated system. Here, we introduce bulk numbers that capture the exact number of in-gap modes, without any such subtleties in one spatial dimension. Similarly, based on these 1D bulk numbers, we define a new 2D winding number, which we call the pole winding number, that specifies the number of robust metallic surface bands in the gap as well as their topological character. The underlying general methodology relies on a simple continuous extrapolation from the bulk to the boundary, while tracking the evolution of Green's function's poles in the vicinity of the bulk band edges. As a main result we find that all the obtained numbers can be applied to the known insulating phases in a unified manner regardless of the specific symmetries. Additionally, from a computational point of view, these numbers can be effectively evaluated without any gauge fixing problems. In particular, we directly apply our bulk-boundary correspondence construction to various systems, including 1D examples without a traditional bulk-boundary correspondence, and predict the existence of boundary modes on various experimentally studied graphene edges, such as open boundaries and grain boundaries. Finally, we sketch the 3D generalization of the pole winding number by in the context of topological insulators.
Grain boundaries and defects in superconducting Bi-Sr-Ca-Cu-O ceramics

International Nuclear Information System (INIS)

Ramesh, R.; Bagley, B.G.; Tarascon, J.M.; Green, S.M.; Rudee, M.L.; Luo, H.L.

1990-01-01

Defects and structural interfaces in superconducting Bi-Sr-Ca-Cu-O have been characterized by transmission electron microscopy. The superconducting phase exhibits frequent variations in the stacking sequence (polytypoids). Dislocations, observed inside the grains, either introduce or accommodate the shear in the a-b plane and the local composition fluctuations. In general, the grains exhibit a platelike morphology with the a-b plane as the grain boundary plane. Grain boundaries along the short edge are generally disordered, whereas those near the long edge generally have a thin layer of the lower T c polytypoid. Coherent intragranular boundaries are also observed
Towards understanding edge localised mode mitigation by resonant magnetic perturbations in MAST

Energy Technology Data Exchange (ETDEWEB)

Chapman, I. T.; Kirk, A.; Ham, C. J.; Harrison, J. R.; Liu, Y. Q.; Saarelma, S.; Scannell, R.; Thornton, A. J.; Team, MAST [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Becoulet, M.; Orain, F. [Association Euratom/CEA, CEA Cadarache, IRFM, F-13108, St. Paul-lez-Durance (France); Cooper, W. A. [CRPP, Association EURATOM/Confédération Suisse, EPFL, 1015 Lausanne (Switzerland); Pamela, S. [IIFS-PIIM. Aix Marseille Université—CNRS, 13397 Marseille Cedex 20 (France)

2013-05-15

Type-I Edge Localised Modes (ELMs) have been mitigated in MAST through the application of n=3,4, and 6 resonant magnetic perturbations. For each toroidal mode number of the non-axisymmetric applied fields, the frequency of the ELMs has been increased significantly, and the peak heat flux on the divertor plates reduced commensurately. This increase in ELM frequency occurs despite a significant drop in the edge pressure gradient, which would be expected to stabilise the peeling-ballooning modes thought to be responsible for type-I ELMs. Various mechanisms which could cause a destabilisation of the peeling-ballooning modes are presented, including pedestal widening, plasma rotation braking, three dimensional corrugation of the plasma boundary, and the existence of radially extended lobe structures near to the X-point. This leads to a model aimed at resolving the apparent dichotomy of ELM control, which is to say ELM suppression occurring due to the pedestal pressure reduction below the peeling-ballooning stability boundary, whilst the reduction in pressure can also lead to ELM mitigation, which is ostensibly a destabilisation of peeling-ballooning modes. In the case of ELM mitigation, the pedestal broadening, 3d corrugation, or lobes near the X-point degrade ballooning stability so much that the pedestal recovers rapidly to cross the new stability boundary at lower pressure more frequently, whilst in the case of suppression, the plasma parameters are such that the particle transport reduces the edge pressure below the stability boundary, which is only mildly affected by negligible rotation braking, small edge corrugation or short, broad lobe structures.
Flow distortion at a dense forest edge

DEFF Research Database (Denmark)

Dellwik, Ebba; Bingöl, Ferhat; Mann, Jakob

2014-01-01

The flow near tall forest edges is complex, yet poorly described. A field experiment using two meteorological masts equipped with sonic anemometers and a horizontally staring lidar was performed upwind and downwind of the interface between an open flat farmland and a tall (hc = 24 m) beech forest......, relative to the measurements upwind of the edge. The lidar data taken at several positions between the masts at 1.25hc show that the minimum wind speed occurred just upwind of the edge. At the 1.25hc level, at the forest mast, the momentum flux (\\documentclass...... qualitatively be explained with the concept of eddy‐blocking by the canopy top, which could also explain the observed increase in lateral variance and the decrease in the vertical variance. Despite the short distance to the edge of approximately 1.5hc, the beginning of a new internal boundary layer was visible...
Prosodic Zhafat based in an exact discipline

Directory of Open Access Journals (Sweden)

Ali Heydari

2015-04-01

Full Text Available Abstract Zahf means farness from the orgion and delay from the purpose and goal. In term of prosody, every change that is occurred in afaeel pricipals is called zahaf. In ancient prosody books, sometime zahafs of persion prosody have been classified in a particular method and approximately scientific, but this method used as a sample for the earliest accoding to different reasons such as: unuseful complications, being of little importance in learning prosody, etc. Maybe these matters are the reason why honorable authors didn’t try to classify them. Among predecessors, Khaja Nasir od-Din has done useful efforts. But his efforts are not enough. The fact is that learning prosodic zahafs in the way mentioned in the most of prosody books is very difficult and probably impossible. Paying attention to these classifications, we can consider zahafs as one of prosody problems in zahafs section. In this essay, to facilitate learning and more importantly to make it long-lasting in the memory, we divide these zahafs in a different way. In a general classification, changes of zahafs in prosody afa’eel are either singular or compound. Singular zahaf: In this case one or some of syllables (short or long in the beginning or at the end are deleted. One syllable is added. One syllebe from beginning, middle or end is changed to a short one. Compound zahaf: In this cases two or three zahaf which have been concurrent by the methods of part one simultanously occurred in a foot, or all of the changes are from one method (for example long different syllable have been shortened two times, or simultaneously a syllable deleted and other syllable is shortened and… that in the most cases for this zahaf obtained from all of those zahafs is created another name or sometimes is not. It’s clear that in the part one (1.1 (shortening long syllable which are the most famous and practical in prosodic zahaf in Persian, each of prosody afaeel (Mafa’eelon, Faelaton
Anderson localization of light near boundaries of disordered photonic lattices

International Nuclear Information System (INIS)

Jovic, Dragana M.; Kivshar, Yuri S.; Denz, Cornelia; Belic, Milivoj R.

2011-01-01

We study numerically the effect of boundaries on Anderson localization of light in truncated two-dimensional photonic lattices in a nonlinear medium. We demonstrate suppression of Anderson localization at the edges and corners, so that stronger disorder is needed near the boundaries to obtain the same localization as in the bulk. We find that the level of suppression depends on the location in the lattice (edge vs corner), as well as on the strength of disorder. We also discuss the effect of nonlinearity on various regimes of Anderson localization.
What is the critical height of leading edge roughness for aerodynamics?

DEFF Research Database (Denmark)

Bak, Christian; Gaunaa, Mac; Olsen, Anders Smærup

2016-01-01

-C2-18 and at three different Reynolds numbers with two different leading edge roughness tape heights. Firstly, an analysis of the momentum thickness as function of Reynolds number was carried out based on the boundary layer theory by Thwaites. Secondly, the wind tunnel measurements combined......In this paper the critical leading edge roughness height is analyzed in two cases: 1) leading edge roughness influencing the lift-drag ratio and 2) leading edge roughness influencing the maximum lift. The analysis was based on wind tunnel measurements on the airfoils NACA0015, Risoe-B1-18 and Risoe...
X-ray imaging characterization of active edge silicon pixel sensors

International Nuclear Information System (INIS)

Ponchut, C; Ruat, M; Kalliopuska, J

2014-01-01

The aim of this work was the experimental characterization of edge effects in active-edge silicon pixel sensors, in the frame of X-ray pixel detectors developments for synchrotron experiments. We produced a set of active edge pixel sensors with 300 to 500 μm thickness, edge widths ranging from 100 μm to 150 μm, and n or p pixel contact types. The sensors with 256 × 256 pixels and 55 × 55 μm 2 pixel pitch were then bump-bonded to Timepix readout chips for X-ray imaging measurements. The reduced edge widths makes the edge pixels more sensitive to the electrical field distribution at the sensor boundaries. We characterized this effect by mapping the spatial response of the sensor edges with a finely focused X-ray synchrotron beam. One of the samples showed a distortion-free response on all four edges, whereas others showed variable degrees of distortions extending at maximum to 300 micron from the sensor edge. An application of active edge pixel sensors to coherent diffraction imaging with synchrotron beams is described
Bulk-edge correspondence in topological transport and pumping

Science.gov (United States)

Imura, Ken-Ichiro; Yoshimura, Yukinori; Fukui, Takahiro; Hatsugai, Yasuhiro

2018-03-01

The bulk-edge correspondence (BEC) refers to a one-to-one relation between the bulk and edge properties ubiquitous in topologically nontrivial systems. Depending on the setup, BEC manifests in different forms and govern the spectral and transport properties of topological insulators and semimetals. Although the topological pump is theoretically old, BEC in the pump has been established just recently [1] motivated by the state-of-the-art experiments using cold atoms [2, 3]. The center of mass (CM) of a system with boundaries shows a sequence of quantized jumps in the adiabatic limit associated with the edge states. Despite that the bulk is adiabatic, the edge is inevitably non-adiabatic in the experimental setup or in any numerical simulations. Still the pumped charge is quantized and carried by the bulk. Its quantization is guaranteed by a compensation between the bulk and edges. We show that in the presence of disorder the pumped charge continues to be quantized despite the appearance of non-quantized jumps.
Determination of graphene's edge energy using hexagonal graphene quantum dots and PM7 method.

Science.gov (United States)

Vorontsov, Alexander V; Tretyakov, Evgeny V

2018-05-18

Graphene quantum dots (GQDs) are important for a variety of applications and designs, and the shapes of GQDs rely on the energy of their boundaries. Presently, many methods have been developed for the preparation of GQDs with the required boundaries, shapes and edge terminations. However, research on the properties of GQDs and their applications is limited due to the unavailability of these compounds in pure form. In the present computational study, the standard enthalpy of formation, the standard enthalpy of formation of edges and the standard enthalpy of hydrogenation are studied for hexagonal GQDs with purely zigzag and armchair edges in non-passivated and H-passivated forms using the semiempirical quantum chemistry method pm7. The standard enthalpy of formation of the edge is found to remain constant for GQDs studied in the range of 1 to 6 nm, and the enthalpies of edge C atoms are 32.4 and 35.5 kcal mol-1 for armchair and zigzag edges, respectively. In contrast to some literature data, the standard enthalpy of formation of hydrogenated edges is far from zero, and the values are 7.3 and 8.0 kcal mol-1 C for armchair and zigzag edges, respectively. The standard enthalpy of hydrogenation is found to be -10.2 and -9.72 eV nm-1 for the armchair and zigzag edges, respectively.
Trapping of low-mass planets outside the truncated inner edges of protoplanetary discs

Science.gov (United States)

Miranda, Ryan; Lai, Dong

2018-02-01

We investigate the migration of a low-mass (≲10 M⊕) planet near the inner edge of a protoplanetary disc using two-dimensional viscous hydrodynamics simulations. We employ an inner boundary condition representing the truncation of the disc at the stellar corotation radius. As described by Tsang, wave reflection at the inner disc boundary modifies the Type I migration torque on the planet, allowing migration to be halted before the planet reaches the inner edge of the disc. For low-viscosity discs (α ≲ 10-3), planets may be trapped with semi-major axes as large as three to five times the inner disc radius. In general, planets are trapped closer to the inner edge as either the planet mass or the disc viscosity parameter α increases, and farther from the inner edge as the disc thickness is increased. This planet trapping mechanism may impact the formation and migration history of close-in compact multiplanet systems.
IMAGE ANALYSIS BASED ON EDGE DETECTION TECHNIQUES

Institute of Scientific and Technical Information of China (English)

纳瑟; 刘重庆

2002-01-01

A method that incorporates edge detection technique, Markov Random field (MRF), watershed segmentation and merging techniques was presented for performing image segmentation and edge detection tasks. It first applies edge detection technique to obtain a Difference In Strength (DIS) map. An initial segmented result is obtained based on K-means clustering technique and the minimum distance. Then the region process is modeled by MRF to obtain an image that contains different intensity regions. The gradient values are calculated and then the watershed technique is used. DIS calculation is used for each pixel to define all the edges (weak or strong) in the image. The DIS map is obtained. This help as priority knowledge to know the possibility of the region segmentation by the next step (MRF), which gives an image that has all the edges and regions information. In MRF model,gray level l, at pixel location i, in an image X, depends on the gray levels of neighboring pixels. The segmentation results are improved by using watershed algorithm. After all pixels of the segmented regions are processed, a map of primitive region with edges is generated. The edge map is obtained using a merge process based on averaged intensity mean values. A common edge detectors that work on (MRF) segmented image are used and the results are compared. The segmentation and edge detection result is one closed boundary per actual region in the image.
Generic boundary scattering in the open XXZ chain

International Nuclear Information System (INIS)

Doikou, Anastasia

2008-01-01

The open critical XXZ spin chain with a general right boundary and a trivial diagonal left boundary is considered. Within this framework we propose a simple computation of the exact generic boundary S-matrix (with diagonal and non-diagonal entries), starting from the 'bare' Bethe ansatz equations. Our results as anticipated coincide with the ones obtained by Ghoshal and Zamolodchikov, after assuming suitable identifications of the bulk and boundary parameters
Phonon cross-plane transport and thermal boundary resistance: effect of heat source size and thermal boundary resistance on phonon characteristics

Science.gov (United States)

Ali, H.; Yilbas, B. S.

2016-09-01

Phonon cross-plane transport across silicon and diamond thin films pair is considered, and thermal boundary resistance across the films pair interface is examined incorporating the cut-off mismatch and diffusive mismatch models. In the cut-off mismatch model, phonon frequency mismatch for each acoustic branch is incorporated across the interface of the silicon and diamond films pair in line with the dispersion relations of both films. The frequency-dependent and transient solution of the Boltzmann transport equation is presented, and the equilibrium phonon intensity ratios at the silicon and diamond film edges are predicted across the interface for each phonon acoustic branch. Temperature disturbance across the edges of the films pair is incorporated to assess the phonon transport characteristics due to cut-off and diffusive mismatch models across the interface. The effect of heat source size, which is allocated at high-temperature (301 K) edge of the silicon film, on the phonon transport characteristics at the films pair interface is also investigated. It is found that cut-off mismatch model predicts higher values of the thermal boundary resistance across the films pair interface as compared to that of the diffusive mismatch model. The ratio of equilibrium phonon intensity due to the cut-off mismatch over the diffusive mismatch models remains >1 at the silicon edge, while it becomes <1 at the diamond edge for all acoustic branches.
Objective voice and speech analysis of persons with chronic hoarseness by prosodic analysis of speech samples.

Science.gov (United States)

Haderlein, Tino; Döllinger, Michael; Matoušek, Václav; Nöth, Elmar

2016-10-01

Automatic voice assessment is often performed using sustained vowels. In contrast, speech analysis of read-out texts can be applied to voice and speech assessment. Automatic speech recognition and prosodic analysis were used to find regression formulae between automatic and perceptual assessment of four voice and four speech criteria. The regression was trained with 21 men and 62 women (average age 49.2 years) and tested with another set of 24 men and 49 women (48.3 years), all suffering from chronic hoarseness. They read the text 'Der Nordwind und die Sonne' ('The North Wind and the Sun'). Five voice and speech therapists evaluated the data on 5-point Likert scales. Ten prosodic and recognition accuracy measures (features) were identified which describe all the examined criteria. Inter-rater correlation within the expert group was between r = 0.63 for the criterion 'match of breath and sense units' and r = 0.87 for the overall voice quality. Human-machine correlation was between r = 0.40 for the match of breath and sense units and r = 0.82 for intelligibility. The perceptual ratings of different criteria were highly correlated with each other. Likewise, the feature sets modeling the criteria were very similar. The automatic method is suitable for assessing chronic hoarseness in general and for subgroups of functional and organic dysphonia. In its current version, it is almost as reliable as a randomly picked rater from a group of voice and speech therapists.
Electrophysiology of prosodic and lexical-semantic processing during sentence comprehension in aphasia.

Science.gov (United States)

Sheppard, Shannon M; Love, Tracy; Midgley, Katherine J; Holcomb, Phillip J; Shapiro, Lewis P

2017-12-01

Event-related potentials (ERPs) were used to examine how individuals with aphasia and a group of age-matched controls use prosody and themattic fit information in sentences containing temporary syntactic ambiguities. Two groups of individuals with aphasia were investigated; those demonstrating relatively good sentence comprehension whose primary language difficulty is anomia (Individuals with Anomic Aphasia (IWAA)), and those who demonstrate impaired sentence comprehension whose primary diagnosis is Broca's aphasia (Individuals with Broca's Aphasia (IWBA)). The stimuli had early closure syntactic structure and contained a temporary early closure (correct)/late closure (incorrect) syntactic ambiguity. The prosody was manipulated to either be congruent or incongruent, and the temporarily ambiguous NP was also manipulated to either be a plausible or an implausible continuation for the subordinate verb (e.g., "While the band played the song/the beer pleased all the customers."). It was hypothesized that an implausible NP in sentences with incongruent prosody may provide the parser with a plausibility cue that could be used to predict syntactic structure. The results revealed that incongruent prosody paired with a plausibility cue resulted in an N400-P600 complex at the implausible NP (the beer) in both the controls and the IWAAs, yet incongruent prosody without a plausibility cue resulted in an N400-P600 at the critical verb (pleased) only in healthy controls. IWBAs did not show evidence of N400 or P600 effects at the ambiguous NP or critical verb, although they did show evidence of a delayed N400 effect at the sentence-final word in sentences with incongruent prosody. These results suggest that IWAAs have difficulty integrating prosodic cues with underlying syntactic structure when lexical-semantic information is not available to aid their parse. IWBAs have difficulty integrating both prosodic and lexical-semantic cues with syntactic structure, likely due to a

Longitudinal vortices in a transitioning boundary layer

International Nuclear Information System (INIS)

Anders, J.B.; Backwelder, R.F.

1980-01-01

Naturally occurring spanwise variations of the streamwise velocity component, characteristic of longitudinal vortices embedded in a transitioning boundary layer were explored using hot-wire anemometers. A vibrating ribbon introduced stable or unstable Tollmien-Schlichting waves into the laminar boundary layer. These damped or growing disturbances always developed a strong three-dimensional pattern even though no spanwise perturbations were artificially induced. Changing the radius of the leading edge and other modifications to the flat plate, wind tunnel and boundary layer did not alter the spanwise wavelength of the vortices. (orig.)
Detection of left ventricular epi- and endocardial borders using coupled active contours

NARCIS (Netherlands)

Spreeuwers, Lieuwe Jan; Breeuwer, M.

2003-01-01

Active contours are a popular method for extraction of object boundaries in medical images. However, they may fail to give correct results if there are other edges in the neighbourhood. To handle and even exploit a geometrical relation between neighbouring boundaries, we propose to use a set of
The effect of L1 prosodic backgrounds of Cantonese and Japanese speakers on the perception of Mandarin tones after training

Science.gov (United States)

So, Connie K.

2005-04-01

The present study investigated to what extent ones' L1 prosodic backgrounds affect their learning of a new tonal system. The question as to whether native speakers of a tone language perform differently from those of a pitch accent language will be addressed. Twenty native speakers of Hong Kong Cantonese (a tone language) and Japanese (a pitch accent language) were assigned to two groups. All of them had had no prior knowledge of Mandarin, and had never received any form of musical training before they participated in the study. Their performance of the identification of Mandarin tones before and after a short-term training was compared. Analysis of listeners' tonal confusions in the pretest, posttest, and generalization tests revealed that both Cantonese and Japanese listeners had more confusion for two contrastive tone pairs: Tone 1-Tone 4, and Tone 2-Tone 3. Moreover, Cantonese speakers consistently had greater difficulty than Japanese speakers in distinguishing the tones in each pair. These imply that listeners L1 prosodic backgrounds are at work during the process of learning a new tonal system. The findings will be further discussed in terms of the Perceptual Assimilation Model (Best, 1995). [Work supported by SSHRC.
Initial experience with percutaneous edge-to-edge transcatheter mitral valve repair in a tertiary medical center in Taiwan

Directory of Open Access Journals (Sweden)

Ching-Wei Lee

2018-04-01

Full Text Available Background: The transcatheter edge-to-edge mitral valve repair, using MitraClip, has been a safe and effective treatment for severe mitral regurgitation (SMR in the westerners. However, the therapeutic results of the MitralClip in Taiwan remained elucidated. Methods: Patients with symptomatic SMR were evaluated by the heart team. For those with high or prohibitive surgical risks, transcatheter mitral valve repair was performed in hybrid operation room. During procedure, continuous hemodynamic monitoring was conducted. Transthoracic echocardiography (TTE, blood tests, and six-minute walk test (6MWT were performed before and 1-month after surgery. Results: A total of 20 patients (73.4 ± 11.1 years, 85% male with a mean Euroscore II of 13.2 ± 17.7% and a mean STS score of 8.7 ± 9.0% for mortality were enrolled. After a mean procedural time of 239 ± 95 min, an average of 1.8 ± 0.7 clips were used in each procedure. The procedural successful rate was 95% to achieve mild residual mitral regurgitation. Cardiac output was increased from 3.6 ± 0.9 to 4.6 ± 1.4 (p = 0.008 and V-wave of left atrial pressure declined from 24.4 ± 9.8 to 19.3 ± 7.1 (p = 0.030 immediately during the index procedure. There was no peri-procedural death, myocardial infarction, stroke or any events requiring emergent cardiac surgery. All patients experienced significant improvement in heart failure symptoms. The 6-min walk distance increased from 219.6 ± 118.4 m to 279.1 ± 111.6 (p = 0.04 at 1 month. The echocardiogram further showed significant improvements of mitral regurgitation, pulmonary artery systolic pressure, and the left ventricular end-diastolic volume. Conclusion: Trans-catheter edge-to-edge mitral valve repairs are safe and effective in Asians with symptomatic SMR, regarding the improvements of clinical symptoms and exercise capacities. MitraClips is also associated with reverse remodeling of pulmonary hypertension and left
Experimental investigation of heat transfer and friction factor characteristics of thermosyphon solar water heater system fitted with spacer at the trailing edge of Left-Right twisted tapes

International Nuclear Information System (INIS)

Jaisankar, S.; Radhakrishnan, T.K.; Sheeba, K.N.; Suresh, S.

2009-01-01

Experimental investigation of heat transfer and friction factor characteristics of thermosyphon solar water heater with full length Left-Right twist, twist fitted with rod and spacer at the trailing edge for lengths of 100, 200 and 300 mm for twist ratio 3 and 5 has been studied. The experimental data for plain tube collector has been compared with fundamental equation within a discrepancy of ±7.41% and ±14.97% for Nusselt number and friction factor, respectively. Result shows that the Nusselt number decreases by 11% and 19% for twist fitted with rod and twist with spacer, respectively, when compared with full length twist. Friction factor also decreases by 18% and 29% for twist fitted with rod and spacer, respectively, as compared with full length twist. The heat enhancement in twist fitted with rod at the trailing edge is maximum when compared with twist fitted with spacer because the swirl flow is maintained throughout the length of rod.
A Novel Approach for Automatic Machining Feature Recognition with Edge Blend Feature

OpenAIRE

Keong Chen Wong; Yusof Yusri

2017-01-01

This paper presents an algorithm for efficiently recognizing and determining the convexity of an edge blend feature. The algorithm first recognizes all of the edge blend features from the Boundary Representation of a part; then a series of convexity test have been run on the recognized edge blend features. The novelty of the presented algorithm lies in, instead of each recognized blend feature is suppressed as most of researchers did, the recognized blend features of this research are gone th...
Keeping the band together: evidence for false boundary disruptive coloration in a butterfly.

Science.gov (United States)

Seymoure, B M; Aiello, A

2015-09-01

There is a recent surge of evidence supporting disruptive coloration, in which patterns break up the animal's outline through false edges or boundaries, increasing survival in animals by reducing predator detection and/or preventing recognition. Although research has demonstrated that false edges are successful for reducing predation of prey, research into the role of internal false boundaries (i.e. stripes and bands) in reducing predation remains warranted. Many animals have stripes and bands that may function disruptively. Here, we test the possible disruptive function of wing band patterning in a butterfly, Anartia fatima, using artificial paper and plasticine models in Panama. We manipulated the band so that one model type had the band shifted to the wing margin (nondisruptive treatment) and another model had a discontinuous band located on the wing margin (discontinuous edge treatment). We kept the natural wing pattern to represent the false boundary treatment. Across all treatment groups, we standardized the area of colour and used avian visual models to confirm a match between manipulated and natural wing colours. False boundary models had higher survival than either the discontinuous edge model or the nondisruptive model. There was no survival difference between the discontinuous edge model and the nondisruptive model. Our results demonstrate the importance of wing bands in reducing predation on butterflies and show that markings set in from the wing margin can reduce predation more effectively than marginal bands and discontinuous marginal patterns. This study demonstrates an adaptive benefit of having stripes and bands. © 2015 European Society For Evolutionary Biology.
Theory of Magnetic Edge States in Chiral Graphene Nanoribbons

Science.gov (United States)

Capaz, Rodrigo; Yazyev, Oleg; Louie, Steven

2011-03-01

Using a model Hamiltonian approach including electron Coulomb interactions, we systematically investigate the electronic structure and magnetic properties of chiral graphene nanoribbons. We show that the presence of magnetic edge states is an intrinsic feature of any smooth graphene nanoribbons with chiral edges, and discover a number of structure-property relations. Specifically, we describe how the edge-state energy gap, zone-boundary edge-state energy splitting, and magnetic moment per edge length depend on the nanoribbon width and chiral angle. The role of environmental screening effects is also studied. Our results address a recent experimental observation of signatures of magnetic ordering at smooth edges of chiral graphene nanoribbons and provide an avenue towards tuning their properties via the structural and environmental degrees of freedom. This work was supported by National Science Foundation Grant No. DMR10-1006184, the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and the ONR MURI program. RBC acknowledges financial support from Brazilian agencies CNPq, FAPERJ and INCT-Nanomateriais de Carbono.
The energetic ion substorm injection boundary

International Nuclear Information System (INIS)

Lopez, R.E.; Sibeck, D.G.; McEntire, R.W.; Krimigis, S.M.

1990-01-01

The substorm injection boundary model has enjoyed considerable success in explaining plasma signatures in the near-geosynchronous region. However, the injection boundary has remained primarily a phenomenological model. In this paper the authors examine 167 dispersionless energetic ion injections which were observed by AMPTE CCE. The radial and local time distribution of the events as a function of Kp is qualitatively similar to that envisioned in the injection boundary model of Mauk and McIlwain (1974). They argue that particles observed during dispersionless injections are locally energized during the disruption of the cross-tail current sheet. Therefore they identify the injection boundary, as derived from the spatial distribution of dispersionless injections, with the earthward edge of the region of the magnetotail which undergoes current sheet disruption during the substorm expansion phase. The authors show that this qualitative model for the generation of the injection boundary can provide an explanation for the dispersionless nature, the double spiral shape, and the Kp dependence of the boundary
On the Dynamics of Edge-core Coupling

Energy Technology Data Exchange (ETDEWEB)

Hahm,T.S.; Diamond, P.H.; Lin, Z.; Rewoldt, G.; Gurcan, O.; Ethier, S.

2005-08-26

One of the nagging, unresolved questions in fusion theory is concerned with the extent of the edge. Gyrokinetic particle simulations of toroidal ion temperature gradient (ITG) turbulence spreading using the Gyrokinetic Toroidal Code (GTC) [Z. Lin et al., Science 281, 1835 (1998)] and its related dynamical model have been extended to a system with radially varying ion temperature gradient, in order to study the inward spreading of edge turbulence toward the core plasma. Due to such spreading, the turbulence intensity in the core region is significantly enhanced over the value obtained from simulations of the core region only, and the precise boundary of the edge region is blurred. Even when the core gradient is within the Dimits shift regime (i.e., dominated by self-generated zonal flows which reduce the transport to a negligible value), a significant level of turbulence can penetrate to the core due to spreading from the edge. The scaling of the turbulent front propagation speed is closer to the prediction from a nonlinear diffusion model than from one based on linear toroidal coupling.
Research, Boundaries, and Policy in Networked Learning

DEFF Research Database (Denmark)

This book presents cutting-edge, peer reviewed research on networked learning organized by three themes: policy in networked learning, researching networked learning, and boundaries in networked learning. The "policy in networked learning" section explores networked learning in relation to policy...... networks, spaces of algorithmic governance and more. The "boundaries in networked learning" section investigates frameworks of students' digital literacy practices, among other important frameworks in digital learning. Lastly, the "research in networked learning" section delves into new research methods...
Prosodic Zhafat based in an exact discipline

Directory of Open Access Journals (Sweden)

Ali Heydari

2015-03-01

Full Text Available Abstract Zahf means farness from the orgion and delay from the purpose and goal. In term of prosody, every change that is occurred in afaeel pricipals is called zahaf. Â In ancient prosody books, sometime zahafs of persion prosody have been classified in a particular method and approximately scientific, but this method used as a sample for the earliest accoding to different reasons such as: unuseful complications, being of little importance in learning prosody, etc.Â Maybe these matters are the reason why honorable authors didnât try to classify them. Â Among predecessors, Khaja Nasir od-Din has done useful efforts. But his efforts are not enough. The fact is that learning prosodic zahafs in the way mentioned in the most of prosody books is very difficult and probably impossible. Paying attention to these classifications, we can consider zahafs as one of prosody problems in zahafs section. Â In this essay, to facilitate learning and more importantly to make it long-lasting in the memory, we divide these zahafs in a different way. In a general classification, changes of zahafs in prosody afaâeel are either singular or compound. Singular zahaf: In this case one or some of syllables (short or long in the beginning or at the end are deleted. One syllable is added. One syllebe from beginning, middle or end is changed to a short one. Compound zahaf: In this cases two or three zahaf which have been concurrent by the methods of part one simultanously occurred in a foot, or all of the changes are from one method (for example long different syllable have been shortened two times, or simultaneously a syllable deleted and other syllable is shortened andâ¦ that in the most cases for this zahaf obtained from all of those zahafs is created another name or sometimes is not. Itâs clear that in the part one (1.1 (shortening long syllable which are the most famous and practical in prosodic zahaf in Persian, each of prosody afaeel
BSLIC: SLIC Superpixels Based on Boundary Term

Directory of Open Access Journals (Sweden)

Hai Wang

2017-02-01

Full Text Available A modified method for better superpixel generation based on simple linear iterative clustering (SLIC is presented and named BSLIC in this paper. By initializing cluster centers in hexagon distribution and performing k-means clustering in a limited region, the generated superpixels are shaped into regular and compact hexagons. The additional cluster centers are initialized as edge pixels to improve boundary adherence, which is further promoted by incorporating the boundary term into the distance calculation of the k-means clustering. Berkeley Segmentation Dataset BSDS500 is used to qualitatively and quantitatively evaluate the proposed BSLIC method. Experimental results show that BSLIC achieves an excellent compromise between boundary adherence and regularity of size and shape. In comparison with SLIC, the boundary adherence of BSLIC is increased by at most 12.43% for boundary recall and 3.51% for under segmentation error.
Network Unfolding Map by Vertex-Edge Dynamics Modeling.

Science.gov (United States)

Verri, Filipe Alves Neto; Urio, Paulo Roberto; Zhao, Liang

2018-02-01

The emergence of collective dynamics in neural networks is a mechanism of the animal and human brain for information processing. In this paper, we develop a computational technique using distributed processing elements in a complex network, which are called particles, to solve semisupervised learning problems. Three actions govern the particles' dynamics: generation, walking, and absorption. Labeled vertices generate new particles that compete against rival particles for edge domination. Active particles randomly walk in the network until they are absorbed by either a rival vertex or an edge currently dominated by rival particles. The result from the model evolution consists of sets of edges arranged by the label dominance. Each set tends to form a connected subnetwork to represent a data class. Although the intrinsic dynamics of the model is a stochastic one, we prove that there exists a deterministic version with largely reduced computational complexity; specifically, with linear growth. Furthermore, the edge domination process corresponds to an unfolding map in such way that edges "stretch" and "shrink" according to the vertex-edge dynamics. Consequently, the unfolding effect summarizes the relevant relationships between vertices and the uncovered data classes. The proposed model captures important details of connectivity patterns over the vertex-edge dynamics evolution, in contrast to the previous approaches, which focused on only vertex or only edge dynamics. Computer simulations reveal that the new model can identify nonlinear features in both real and artificial data, including boundaries between distinct classes and overlapping structures of data.
Information processing in patterned magnetic nanostructures with edge spin waves.

Science.gov (United States)

Lara, Antonio; Robledo Moreno, Javier; Guslienko, Konstantin Y; Aliev, Farkhad G

2017-07-17

Low dissipation data processing with spins is one of the promising directions for future information and communication technologies. Despite a significant progress, the available magnonic devices are not broadband yet and have restricted capabilities to redirect spin waves. Here we propose a breakthrough approach to spin wave manipulation in patterned magnetic nanostructures with unmatched characteristics, which exploits a spin wave analogue to edge waves propagating along a water-wall boundary. Using theory, micromagnetic simulations and experiment we investigate spin waves propagating along the edges in magnetic structures, under an in-plane DC magnetic field inclined with respect to the edge. The proposed edge spin waves overcome important challenges faced by previous technologies such as the manipulation of the spin wave propagation direction, and they substantially improve the capability of transmitting information at frequencies exceeding 10 GHz. The concept of the edge spin waves allows to design a broad of logic devices such as splitters, interferometers, or edge spin wave transistors with unprecedented characteristics and a potentially strong impact on information technologies.
Left Dislocation in North-Eastern Neo-Aramaic dialects

African Journals Online (AJOL)

Andrason, A, Dr

Such initial items have all the semantic and functional properties of normal grammatical subjects. These are referred to as LD1 structures. A distinct type of construction is where the initial item is less integrated prosodically and/or structurally with what follows. This is referred to as an LD2 structure. This includes cases where ...
External kink mode stability of tokamaks with finite edge current density in plasma outside separatrix

International Nuclear Information System (INIS)

Degtyarev, L.; Martynov, A.; Medvedev, S.; Troyon, F.; Villard, L.

1996-01-01

Large pressure gradients and current density at the plasma edge and accompanying edge-localized MHD instabilities are typical for H-mode discharges. Low-n external kink modes are a possible cause of the instabilities. The paper mostly deals with external kink modes driven by a finite current density at the plasma boundary (so called peeling modes). It was shown earlier that for a single axis plasma embedded into vacuum the peeling modes are stabilized when separatrix is approaching the plasma boundary. For doublet configurations a finite current density at the internal separatrix does not necessarily lead to external kink instability when the current density vanishes at the boundary. However, a finite current density at the plasma boundary outside the separatrix can drive outer peeling modes. The stability properties and structure of these modes depend on the plasma equilibrium outside the separatrix. The influence of plasma shear and pressure gradient at the boundary on the stability of the outer peeling modes in doublets is studied. The stability of kink modes in divertor configurations with plasma outside the separatrix is very sensitive to the boundary conditions set at open field lines. The choice of the boundary conditions and kink mode stability calculations for the divertor configurations are discussed. (author) 4 figs., 5 refs
Algorithms for boundary detection in radiographic images

International Nuclear Information System (INIS)

Gonzaga, Adilson; Franca, Celso Aparecido de

1996-01-01

Edge detecting techniques applied to radiographic digital images are discussed. Some algorithms have been implemented and the results are displayed to enhance boundary or hide details. An algorithm applied in a pre processed image with contrast enhanced is proposed and the results are discussed
Overview of edge turbulence and zonal flow studies on TEXTOR

International Nuclear Information System (INIS)

Xu, Y.; Kraemer-Flecken, A.; Reiser, D.

2008-01-01

In the TEXTOR tokamak, the edge turbulence properties and turbulence-associated zonal flows have been systematically investigated both experimentally and theoretically. The experimental results include the investigation of self-organized criticality (SOC) behavior, the intermittent blob transport and the geodesic acoustic mode (GAM) zonal flows. During the Dynamic Ergodic Divertor (DED) operation in TEXTOR, the impact of an ergodized plasma boundary on edge turbulence, turbulent transport and the fluctuation propagation has also been studied in detail. The results show substantial influence by the DED on edge turbulence. The theoretical simulations for TEXTOR parameters show characteristic features of the GAM flows and strong reduction of the blob transport by the DED at the plasma periphery. Moreover, the modelling reveals the importance of the Reynolds stress in driving mean (or zonal) flows at the plasma edge in the ohmic discharge phase in TEXTOR. (author)
How disturbance, competition, and dispersal interact to prevent tree range boundaries from keeping pace with climate change.

Science.gov (United States)

Liang, Yu; Duveneck, Matthew J; Gustafson, Eric J; Serra-Diaz, Josep M; Thompson, Jonathan R

2018-01-01

Climate change is expected to cause geographic shifts in tree species' ranges, but such shifts may not keep pace with climate changes because seed dispersal distances are often limited and competition-induced changes in community composition can be relatively slow. Disturbances may speed changes in community composition, but the interactions among climate change, disturbance and competitive interactions to produce range shifts are poorly understood. We used a physiologically based mechanistic landscape model to study these interactions in the northeastern United States. We designed a series of disturbance scenarios to represent varied disturbance regimes in terms of both disturbance extent and intensity. We simulated forest succession by incorporating climate change under a high-emissions future, disturbances, seed dispersal, and competition using the landscape model parameterized with forest inventory data. Tree species range boundary shifts in the next century were quantified as the change in the location of the 5th (the trailing edge) and 95th (the leading edge) percentiles of the spatial distribution of simulated species. Simulated tree species range boundary shifts in New England over the next century were far below (usually change (usually more than 110 km over 100 years) under a high-emissions scenario. Simulated species` ranges shifted northward at both the leading edge (northern boundary) and trailing edge (southern boundary). Disturbances may expedite species' recruitment into new sites, but they had little effect on the velocity of simulated range boundary shifts. Range shifts at the trailing edge tended to be associated with photosynthetic capacity, competitive ability for light and seed dispersal ability, whereas shifts at the leading edge were associated only with photosynthetic capacity and competition for light. This study underscores the importance of understanding the role of interspecific competition and disturbance when studying tree range

A simple highly accurate field-line mapping technique for three-dimensional Monte Carlo modeling of plasma edge transport

International Nuclear Information System (INIS)

Feng, Y.; Sardei, F.; Kisslinger, J.

2005-01-01

The paper presents a new simple and accurate numerical field-line mapping technique providing a high-quality representation of field lines as required by a Monte Carlo modeling of plasma edge transport in the complex magnetic boundaries of three-dimensional (3D) toroidal fusion devices. Using a toroidal sequence of precomputed 3D finite flux-tube meshes, the method advances field lines through a simple bilinear, forward/backward symmetric interpolation at the interfaces between two adjacent flux tubes. It is a reversible field-line mapping (RFLM) algorithm ensuring a continuous and unique reconstruction of field lines at any point of the 3D boundary. The reversibility property has a strong impact on the efficiency of modeling the highly anisotropic plasma edge transport in general closed or open configurations of arbitrary ergodicity as it avoids artificial cross-field diffusion of the fast parallel transport. For stellarator-symmetric magnetic configurations, which are the standard case for stellarators, the reversibility additionally provides an average cancellation of the radial interpolation errors of field lines circulating around closed magnetic flux surfaces. The RFLM technique has been implemented in the 3D edge transport code EMC3-EIRENE and is used routinely for plasma transport modeling in the boundaries of several low-shear and high-shear stellarators as well as in the boundary of a tokamak with 3D magnetic edge perturbations
Dynamics of edge currents in a linearly quenched Haldane model

Science.gov (United States)

Mardanya, Sougata; Bhattacharya, Utso; Agarwal, Amit; Dutta, Amit

2018-03-01

In a finite-time quantum quench of the Haldane model, the Chern number determining the topology of the bulk remains invariant, as long as the dynamics is unitary. Nonetheless, the corresponding boundary attribute, the edge current, displays interesting dynamics. For the case of sudden and adiabatic quenches the postquench edge current is solely determined by the initial and the final Hamiltonians, respectively. However for a finite-time (τ ) linear quench in a Haldane nanoribbon, we show that the evolution of the edge current from the sudden to the adiabatic limit is not monotonic in τ and has a turning point at a characteristic time scale τ =τ0 . For small τ , the excited states lead to a huge unidirectional surge in the edge current of both edges. On the other hand, in the limit of large τ , the edge current saturates to its expected equilibrium ground-state value. This competition between the two limits lead to the observed nonmonotonic behavior. Interestingly, τ0 seems to depend only on the Semenoff mass and the Haldane flux. A similar dynamics for the edge current is also expected in other systems with topological phases.
Grain-size distributions and grain boundaries of chalcopyrite-type thin films

International Nuclear Information System (INIS)

Abou-Ras, D.; Schorr, S.; Schock, H.W.

2007-01-01

CuInSe 2 , CuGaSe 2 , Cu(In,Ga)Se 2 and CuInS 2 thin-film solar absorbers in completed solar cells were studied in cross section by means of electronbackscatter diffraction. From the data acquired, grain-size distributions were extracted, and also the most frequent grain boundaries were determined. The grain-size distributions of all chalcopyrite-type thin films studied can be described well by lognormal distribution functions. The most frequent grainboundary types in these thin films are 60 - left angle 221 right angle tet and 71 - left angle 110 right angle tet (near) Σ3 twin boundaries. These results can be related directly to the importance of {112} tet planes during the topotactical growth of chalcopyrite-type thin films. Based on energetic considerations, it is assumed that the most frequent twin boundaries exhibit a 180 - left angle 221 right angle tet constellation. (orig.)
Immediate integration of prosodic information from speech and visual information from pictures in the absence of focused attention: a mismatch negativity study.

Science.gov (United States)

Li, X; Yang, Y; Ren, G

2009-06-16

Language is often perceived together with visual information. Recent experimental evidences indicated that, during spoken language comprehension, the brain can immediately integrate visual information with semantic or syntactic information from speech. Here we used the mismatch negativity to further investigate whether prosodic information from speech could be immediately integrated into a visual scene context or not, and especially the time course and automaticity of this integration process. Sixteen Chinese native speakers participated in the study. The materials included Chinese spoken sentences and picture pairs. In the audiovisual situation, relative to the concomitant pictures, the spoken sentence was appropriately accented in the standard stimuli, but inappropriately accented in the two kinds of deviant stimuli. In the purely auditory situation, the speech sentences were presented without pictures. It was found that the deviants evoked mismatch responses in both audiovisual and purely auditory situations; the mismatch negativity in the purely auditory situation peaked at the same time as, but was weaker than that evoked by the same deviant speech sounds in the audiovisual situation. This pattern of results suggested immediate integration of prosodic information from speech and visual information from pictures in the absence of focused attention.
Test and Analysis Correlation of Form Impact onto Space Shuttle Wing Leading Edge RCC Panel 8

Science.gov (United States)

Fasanella, Edwin L.; Lyle, Karen H.; Gabrys, Jonathan; Melis, Matthew; Carney, Kelly

2004-01-01

Soon after the Columbia Accident Investigation Board (CAIB) began their study of the space shuttle Columbia accident, "physics-based" analyses using LS-DYNA were applied to characterize the expected damage to the Reinforced Carbon-Carbon (RCC) leading edge from high-speed foam impacts. Forensic evidence quickly led CAIB investigators to concentrate on the left wing leading edge RCC panels. This paper will concentrate on the test of the left-wing RCC panel 8 conducted at Southwest Research Institute (SwRI) and the correlation with an LS-DYNA analysis. The successful correlation of the LS-DYNA model has resulted in the use of LS-DYNA as a predictive tool for characterizing the threshold of damage for impacts of various debris such as foam, ice, and ablators onto the RCC leading edge for shuttle return-to-flight.
Topology and transport in the edge region of RFX-mod helical regimes

International Nuclear Information System (INIS)

Scarin, P.; Vianello, N.; Agostini, M.; Spizzo, G.; Spolaore, M.; Zuin, M.; Cappello, S.; Carraro, L.; Cavazzana, R.; De Masi, G.; Martines, E.; Moresco, M.; Munaretto, S.; Puiatti, M. E.; Valisa, M.

2011-01-01

New edge diagnostics and detailed analysis of magnetic topology have significantly improved the comprehension of the processes developing at the boundary of a reversed-field pinch (RFP) plasma in RFX-mod (a = 0.46 m, R = 2 m). An upper critical density n C ∼ 0.4 n G (n G Greenwald density) is found to limit the operational space for the improved quasi-single helical (QSH) regime: magnetic topology reconstructions and diagnostic observations suggest that this limit is due to a helical plasma-wall interaction which determines toroidally and poloidally localized edge density accumulation and cooling. The experimental evidence is provided by a variety of diagnostics: the magnetic boundary as reconstructed from equilibrium codes reveals a helical deformation, which is well correlated with the modulation of edge pressure profile as reconstructed from the thermal helium beam diagnostic. Correlations with the helical deformation are also observed on the space- and time-resolved patterns of the floating potential measured at the wall, and with the edge plasma flow, obtained from different diagnostics. The relevance of these findings is that understanding the mechanisms that limit the operational space of QSH is decisive in achieving the goal of high-density stationary helical RFP equilibrium.
Helmholtz bright and boundary solitons

International Nuclear Information System (INIS)

Christian, J M; McDonald, G S; Chamorro-Posada, P

2007-01-01

We report, for the first time, exact analytical boundary solitons of a generalized cubic-quintic nonlinear Helmholtz (NLH) equation. These solutions have a linked-plateau topology that is distinct from conventional dark soliton solutions; their amplitude and intensity distributions are spatially delocalized and connect regions of finite and zero wave-field disturbances (suggesting also the classification as 'edge solitons'). Extensive numerical simulations compare the stability properties of recently derived Helmholtz bright solitons, for this type of polynomial nonlinearity, to those of the new boundary solitons. The latter are found to possess a remarkable stability characteristic, exhibiting robustness against perturbations that would otherwise lead to the destabilizing of their bright-soliton counterparts
Edge maps: Representing flow with bounded error

KAUST Repository

Bhatia, Harsh

2011-03-01

Robust analysis of vector fields has been established as an important tool for deriving insights from the complex systems these fields model. Many analysis techniques rely on computing streamlines, a task often hampered by numerical instabilities. Approaches that ignore the resulting errors can lead to inconsistencies that may produce unreliable visualizations and ultimately prevent in-depth analysis. We propose a new representation for vector fields on surfaces that replaces numerical integration through triangles with linear maps defined on its boundary. This representation, called edge maps, is equivalent to computing all possible streamlines at a user defined error threshold. In spite of this error, all the streamlines computed using edge maps will be pairwise disjoint. Furthermore, our representation stores the error explicitly, and thus can be used to produce more informative visualizations. Given a piecewise-linear interpolated vector field, a recent result [15] shows that there are only 23 possible map classes for a triangle, permitting a concise description of flow behaviors. This work describes the details of computing edge maps, provides techniques to quantify and refine edge map error, and gives qualitative and visual comparisons to more traditional techniques. © 2011 IEEE.
Turbulent Helicity in the Atmospheric Boundary Layer

Science.gov (United States)

Chkhetiani, Otto G.; Kurgansky, Michael V.; Vazaeva, Natalia V.

2018-05-01

We consider the assumption postulated by Deusebio and Lindborg (J Fluid Mech 755:654-671, 2014) that the helicity injected into the Ekman boundary layer undergoes a cascade, with preservation of its sign (right- or alternatively left-handedness), which is a signature of the system rotation, from large to small scales, down to the Kolmogorov microscale of turbulence. At the same time, recent direct field measurements of turbulent helicity in the steppe region of southern Russia near Tsimlyansk Reservoir show the opposite sign of helicity from that expected. A possible explanation for this phenomenon may be the joint action of different scales of atmospheric flows within the boundary layer, including the sea-breeze circulation over the test site. In this regard, we consider a superposition of the classic Ekman spiral solution and Prandtl's jet-like slope-wind profile to describe the planetary boundary-layer wind structure. The latter solution mimics a hydrostatic shallow breeze circulation over a non-uniformly heated surface. A 180°-wide sector on the hodograph plane exists, within which the relative orientation of the Ekman and Prandtl velocity profiles favours the left rotation with height of the resulting wind velocity vector in the lowermost part of the boundary layer. This explains the negative (left-handed) helicity cascade toward small-scale turbulent motions, which agrees with the direct field measurements of turbulent helicity in Tsimlyansk. A simple turbulent relaxation model is proposed that explains the measured positive values of the relatively minor contribution to turbulent helicity from the vertical components of velocity and vorticity.
Receptivity of a high-speed boundary layer to temperature spottiness

OpenAIRE

Fedorov, A. V.; Ryzhov, A. A.; Soudakov, V. G.; Utyuzhnikov, S. V.

2013-01-01

Two-dimensional direct numerical simulation (DNS) of the receptivity of a flat-plate boundary layer to temperature spottiness in the Mach 6 free stream is carried out. The influence of spottiness parameters on the receptivity process is studied. It is shown that the temperature spots propagating near the upper boundary-layer edge generate mode F inside the boundary layer. Further downstream mode F is synchronized with unstable mode S (Mack second mode) and excites the latter via the inter-mod...
EXTRACTION OF BUILDING BOUNDARY LINES FROM AIRBORNE LIDAR POINT CLOUDS

Directory of Open Access Journals (Sweden)

Y.-H. Tseng

2016-10-01

Full Text Available Building boundary lines are important spatial features that characterize the topographic maps and three-dimensional (3D city models. Airborne LiDAR Point clouds provide adequate 3D spatial information for building boundary mapping. However, information of boundary features contained in point clouds is implicit. This study focuses on developing an automatic algorithm of building boundary line extraction from airborne LiDAR data. In an airborne LiDAR dataset, top surfaces of buildings, such as roofs, tend to have densely distributed points, but vertical surfaces, such as walls, usually have sparsely distributed points or even no points. The intersection lines of roof and wall planes are, therefore, not clearly defined in point clouds. This paper proposes a novel method to extract those boundary lines of building edges. The extracted line features can be used as fundamental data to generate topographic maps of 3D city model for an urban area. The proposed method includes two major process steps. The first step is to extract building boundary points from point clouds. Then the second step is followed to form building boundary line features based on the extracted boundary points. In this step, a line fitting algorithm is developed to improve the edge extraction from LiDAR data. Eight test objects, including 4 simple low buildings and 4 complicated tall buildings, were selected from the buildings in NCKU campus. The test results demonstrate the feasibility of the proposed method in extracting complicate building boundary lines. Some results which are not as good as expected suggest the need of further improvement of the method.
The L-H transition and the stability of the edge pedestal

International Nuclear Information System (INIS)

Rogers, B.N.; Drake, J.F.; Zeiler, A.

2001-01-01

Based on three-dimensional simulations of the Braginskii equations, we identify two main parameters which control transport in the edge of tokamaks: the MHD ballooning parameter and a diamagnetic parameter. The space defined by these parameters delineates regions where typical L-mode levels of transport arise, where the transport is catastrophically large (density limit) and where the plasma spontaneously forms a transport barrier (H-mode). Ion diamagnetic effects allow the edge pedestal to steepen well beyond the first ideal MHD stability boundary. (author)
Properties on the edge: graphene edge energies, edge stresses, edge warping, and the Wulff shape of graphene flakes

International Nuclear Information System (INIS)

Branicio, Paulo S; Jhon, Mark H; Gan, Chee Kwan; Srolovitz, David J

2011-01-01

It has been shown that the broken bonds of an unreconstructed graphene edge generate compressive edge stresses leading to edge warping. Here, we investigate edge energies and edge stresses of graphene nanoribbons with arbitrary orientations from armchair to zigzag, considering both flat and warped edge shapes in the presence and absence of hydrogen. We use the second generation reactive empirical bond order potential to calculate the edge energies and stresses for clean and hydrogenated edges. Using these energies, we perform a Wulff construction to determine the equilibrium shapes of flat graphene flakes as a function of hydrogen chemical potential. While edge stresses for clean, flat edges are compressive, they become tensile if allowed to warp. Conversely, we find that edge energies change little (∼1%) with edge warping. Hydrogenation of the edges virtually eliminates both the edge energy and edge stresses. For warped edges an approximately linear relationship is found between amplitudes and wavelengths. The equilibrium shape of a graphene flake is determined by the value of the hydrogen chemical potential. For very small (and large) values of it the flakes have a nearly hexagonal (dodecagon) shape with zigzag oriented edges, while for intermediate values graphene flakes are found with complex shapes
Numerical solution of fuzzy boundary value problems using Galerkin ...

Indian Academy of Sciences (India)

1 College of Mathematics and Statistics, Chongqing University, Chongqing 401331, China. 2 Department of ... exact solution of fuzzy first-order boundary value problems. (BVPs). ...... edge partial financial support by the Ministerio de Economıa.
The Trapping of Helium at a Low Angle Tilt Boundary in Molybdenum

NARCIS (Netherlands)

Evans, J.H.; Veen, A. van; Hosson, J.Th.M. De; Bullough, R.; Willis, J.R.

1984-01-01

This paper presents experimental evidence of helium trapping at a set of b = [100] edge dislocations defining a low angle tilt boundary in molybdenum together with theoretical results on two aspects of helium-dislocation behaviour. The low angle boundary, with a misfit angle of ≈1/5 °, was found
Boundary layer measurements of the NACA0015 and implications for noise modeling

Energy Technology Data Exchange (ETDEWEB)

Bertagnolio, F.

2011-01-15

A NACA0015 airfoil section instrumented with an array of high frequency microphones flush-mounted beneath its surface was measured in the wind tunnel at LM Wind Power in Lunderskov. Various inflow speeds and angles of attack were investigated. In addition, a hot-wire device system was used to measure the velocity profiles and turbulence characteristics in the boundary layer near the trailing edge of the airfoil. The measured boundary layer data are presented in this report and compared with CFD results. A relative good agreement is observed, though a few discrepancies also appear. Comparisons of surface pressure fluctuations spectra are used to analyze and improve trailing edge noise modeling by the so-called TNO model. Finally, a pair of hot-wires were placed on each side of the trailing edge in order to measure the radiated trailing edge noise. However, there is no strong evidence that such noise could be measured in the higher frequency range. Nevertheless, low-frequency noise could be measured and related to the presence of the airfoil but its origin is unclear. (Author)
Intelligent identification of remnant ridge edges in region west of Yongxing Island, South China Sea

Science.gov (United States)

Wang, Weiwei; Guo, Jing; Cai, Guanqiang; Wang, Dawei

2018-02-01

Edge detection enables identification of geomorphologic unit boundaries and thus assists with geomorphical mapping. In this paper, an intelligent edge identification method is proposed and image processing techniques are applied to multi-beam bathymetry data. To accomplish this, a color image is generated by the bathymetry, and a weighted method is used to convert the color image to a gray image. As the quality of the image has a significant influence on edge detection, different filter methods are applied to the gray image for de-noising. The peak signal-to-noise ratio and mean square error are calculated to evaluate which filter method is most appropriate for depth image filtering and the edge is subsequently detected using an image binarization method. Traditional image binarization methods cannot manage the complicated uneven seafloor, and therefore a binarization method is proposed that is based on the difference between image pixel values; the appropriate threshold for image binarization is estimated according to the probability distribution of pixel value differences between two adjacent pixels in horizontal and vertical directions, respectively. Finally, an eight-neighborhood frame is adopted to thin the binary image, connect the intermittent edge, and implement contour extraction. Experimental results show that the method described here can recognize the main boundaries of geomorphologic units. In addition, the proposed automatic edge identification method avoids use of subjective judgment, and reduces time and labor costs.
Edge Pedestal Control in Quiescent H-Mode Discharges in DIII-D Using Co Plus Counter Neutral Beam Injection

International Nuclear Information System (INIS)

Burrell, K.H.; Osborne, T.H.; Snyder, P.B.; West, W.P.; Chu, M.S.; Fenstermacher, M.E.; Gohil, P.; Solomon, W.M.

2008-01-01

We have made two significant discoveries in our recent studies of quiescent H-mode (QH-mode) plasmas in DIII-D. First, we have found that we can control the edge pedestal density and pressure by altering the edge particle transport through changes in the edge toroidal rotation. This allows us to adjust the edge operating point to be close to, but below the ELM stability boundary, maintaining the ELM-free state while allowing up to a factor of two increase in edge pressure. The ELM boundary is significantly higher in more strongly shaped plasmas, which broadens the operating space available for QH-mode and leads to improved core performance. Second, for the first time on any tokamak, we have created QH-mode plasmas with strong edge co-rotation; previous QH-modes in all tokamaks had edge counter rotation. This result demonstrates that counter NBI and edge counter rotation are not essential conditions for QH-mode. Both these investigations benefited from the edge stability predictions based on peeling-ballooning mode theory. The broadening of the ELM-stable region with plasma shaping is predicted by that theory. The theory has also been extended to provide a model for the edge harmonic oscillation (EHO) that regulates edge transport in the QH-mode. Many of the features of that theory agree with the experimental results reported either previously or in the present paper. One notable example is the prediction that co-rotating QH-mode is possible provided sufficient shear in the edge rotation can be created
On the location of spectral edges in \\mathbb {Z}-periodic media

KAUST Repository

Exner, Pavel; Kuchment, Peter; Winn, Brian

2010-01-01

Periodic second-order ordinary differential operators on ℝ are known to have the edges of their spectra to occur only at the spectra of periodic and antiperiodic boundary value problems. The multi-dimensional analog of this property is false, as was shown in a 2007 paper by some of the authors of this paper. However, one sometimes encounters the claims that in the case of a single periodicity (i.e., with respect to the lattice ℤ), the 1D property still holds, and spectral edges occur at the periodic and anti-periodic spectra only. In this work, we show that even in the simplest case of quantum graphs this is not true. It is shown that this is true if the graph consists of a 1D chain of finite graphs connected by single edges, while if the connections are formed by at least two edges, the spectral edges can already occur away from the periodic and anti-periodic spectra. © 2010 IOP Publishing Ltd.
On the location of spectral edges in \\mathbb {Z}-periodic media

KAUST Repository

Exner, Pavel

2010-11-09

Periodic second-order ordinary differential operators on ℝ are known to have the edges of their spectra to occur only at the spectra of periodic and antiperiodic boundary value problems. The multi-dimensional analog of this property is false, as was shown in a 2007 paper by some of the authors of this paper. However, one sometimes encounters the claims that in the case of a single periodicity (i.e., with respect to the lattice ℤ), the 1D property still holds, and spectral edges occur at the periodic and anti-periodic spectra only. In this work, we show that even in the simplest case of quantum graphs this is not true. It is shown that this is true if the graph consists of a 1D chain of finite graphs connected by single edges, while if the connections are formed by at least two edges, the spectral edges can already occur away from the periodic and anti-periodic spectra. © 2010 IOP Publishing Ltd.

One-dimensional in-plane edge domain walls in ultrathin ferromagnetic films

Science.gov (United States)

Lund, Ross G.; Muratov, Cyrill B.; Slastikov, Valeriy V.

2018-03-01

We study existence and properties of 1D edge domain walls in ultrathin ferromagnetic films with uniaxial in-plane magnetic anisotropy. In these materials, the magnetization vector is constrained to lie entirely in the film plane, with the preferred directions dictated by the magnetocrystalline easy axis. We consider magnetization profiles in the vicinity of a straight film edge oriented at an arbitrary angle with respect to the easy axis. To minimize the micromagnetic energy, these profiles form transition layers in which the magnetization vector rotates away from the direction of the easy axis to align with the film edge. We prove existence of edge domain walls as minimizers of the appropriate 1D micromagnetic energy functional and show that they are classical solutions of the associated Euler-Lagrange equation with a Dirichlet boundary condition at the edge. We also perform a numerical study of these 1D domain walls and uncover further properties of these domain wall profiles.
Edge compression techniques for visualization of dense directed graphs.

Science.gov (United States)

Dwyer, Tim; Henry Riche, Nathalie; Marriott, Kim; Mears, Christopher

2013-12-01

We explore the effectiveness of visualizing dense directed graphs by replacing individual edges with edges connected to 'modules'-or groups of nodes-such that the new edges imply aggregate connectivity. We only consider techniques that offer a lossless compression: that is, where the entire graph can still be read from the compressed version. The techniques considered are: a simple grouping of nodes with identical neighbor sets; Modular Decomposition which permits internal structure in modules and allows them to be nested; and Power Graph Analysis which further allows edges to cross module boundaries. These techniques all have the same goal--to compress the set of edges that need to be rendered to fully convey connectivity--but each successive relaxation of the module definition permits fewer edges to be drawn in the rendered graph. Each successive technique also, we hypothesize, requires a higher degree of mental effort to interpret. We test this hypothetical trade-off with two studies involving human participants. For Power Graph Analysis we propose a novel optimal technique based on constraint programming. This enables us to explore the parameter space for the technique more precisely than could be achieved with a heuristic. Although applicable to many domains, we are motivated by--and discuss in particular--the application to software dependency analysis.
Preliminary results of structural profiling of the Kras edge and Istria (Kozina – Srmin Motorway, Sečovlje

Directory of Open Access Journals (Sweden)

2002-06-01

Full Text Available On the section Kozina-Srmin the new motorway Ljubljana-Koper is crossing the Kras edge, which in geologic terminology is refered to as the Kras thrust edge. In the widest sense it comprises the area between the edge of the Trieste-Komen plateau and the Savudrija ridge, creating the boundary between the Adriatic foreland and the External Dinarides. Detailed geologic mapping of the motorway section Kozina-Srmin slowed that the Kras thrust edge is not a monophase tectonic structure, but has been formed through several different deformation phases from the Eocene until today. Besides smaller onesthese phases include responses of three significant events; the Dinaric nappe thrusting, displacements along the strice-slipe faults with NW-SE trending and underthrusting of the Istria toward the NE. The latter event destroyed the primary of the SW boundary ofthe External Dinarides between Southern Alps and the Velebit arc.
Edge-spin-derived magnetism in few-layer MoS2 nanomeshes

Directory of Open Access Journals (Sweden)

G. Kondo

2017-12-01

Full Text Available Magnetism arising from edge spins is highly interesting, particularly in 2D atomically thin materials in which the influence of edges becomes more significant. Among such materials, molybdenum disulfide (MoS2; one of the transition metal dichalcogenide (TMD family is attracting significant attention. The causes for magnetism observed in the TMD family, including in MoS2, have been discussed by considering various aspects, such as pure zigzag atomic-structure edges, grain boundaries, and vacancies. Here, we report the observation of ferromagnetism (FM in few-layer MoS2 nanomeshes (NMs; honeycomb-like array of hexagonal nanopores with low-contamination and low-defect pore edges, which have been created by a specific non-lithographic method. We confirm robust FM arising from pore edges in oxygen(O-terminated MoS2-NMs at room temperature, while it disappears in hydrogen(H-terminated samples. The observed high-sensitivity of FM to NM structures and critical annealing temperatures suggest a possibility that the Mo-atom dangling bond in pore edge is a dominant factor for the FM.
Delineation of peatland lagg boundaries from airborne LiDAR

Science.gov (United States)

Langlois, Melanie N.; Richardson, Murray C.; Price, Jonathan S.

2017-09-01

In Canada, peatlands are the most common type of wetland, but boundary delineation in peatland complexes has received little attention in the scientific literature. Typically, peatland boundaries are mapped as crisp, absolute features, and the transitional lagg zone—the ecotone found between a raised bog and the surrounding mineral land—is often overlooked. In this study, we aim (1) to advance existing approaches for detecting and locating laggs and lagg boundaries using airborne LiDAR surveys and (2) to describe the spatial distribution of laggs around raised bog peatlands. Two contrasting spatial analytical approaches for lagg detection were tested using five LiDAR-derived topographic and vegetation indices: topography, vegetation height, topographic wetness index, the standard deviation of the vegetation's height (as a proxy for the complexity of the vegetation's structure), and local indices of elevation variance. Using a dissimilarity approach (edge-detection, split-moving window analysis), no one variable accurately depicted both the lagg-mineral land and bog-lagg boundaries. Some indicators were better at predicting the bog-lagg boundary (i.e., vegetation height) and others at finding the lagg-mineral land boundary (i.e., topography). Dissimilarity analysis reinforces the usefulness of derived variables (e.g., wetness indices) in locating laggs, especially for those with weak topographic and vegetation gradients. When the lagg was confined between the bog and the adjacent upland, it took a linear form, parallel to the peatland's edge and was easier to predict. When the adjacent mineral land was flat or sloping away from the peatland, the lagg was discontinuous and intermittent and more difficult to predict.
Self-consistent model of the low-latitude boundary layer

International Nuclear Information System (INIS)

Phan, T.D.; Sonnerup, B.U.Oe.; Lotko, W.

1989-01-01

A simple two-dimensional, steady state, viscous model of the dawnside and duskside low-latitude boundary layer (LLBL) has been developed. It incorporates coupling to the ionosphere via field-aligned currents and associated field-aligned potential drops, governed by a simple conductance law, and it describes boundary layer currents, magnetic fields, and plasma flow in a self-consistent manner. The magnetic field induced by these currents leads to two effects: (1) a diamagnetic depression of the magnetic field in the equatorial region and (2) bending of the field lines into parabolas in the xz plane with their vertices in the equatorial plane, at z = 0, and pointing in the flow direction, i.e., tailward. Both effects are strongest at the magnetopause edge of the boundary layer and vanish at the magnetospheric edge. The diamagnetic depression corresponds to an excess of plasma pressure in the equatorial boundary layer near the magnetopause. The boundary layer structure is governed by a fourth-order, nonlinear, ordinary differential equation in which one nondimensional parameter, the Hartmann number M, appears. A second parameter, introduced via the boundary conditions, is a nondimensional flow velocity v 0 * at the magnetopause. Numerical results from the model are presented and the possible use of observations to determine the model parameters is discussed. The main new contribution of the study is to provide a better description of the field and plasma configuration in the LLBL itself and to clarify in quantitative terms the circumstances in which induced magnetic fields become important
Characterization of topological phases of dimerized Kitaev chain via edge correlation functions

Science.gov (United States)

Wang, Yucheng; Miao, Jian-Jian; Jin, Hui-Ke; Chen, Shu

2017-11-01

We study analytically topological properties of a noninteracting modified dimerized Kitaev chain and an exactly solvable interacting dimerized Kitaev chain under open boundary conditions by analyzing two introduced edge correlation functions. The interacting dimerized Kitaev chain at the symmetry point Δ =t and the chemical potential μ =0 can be exactly solved by applying two Jordan-Wigner transformations and a spin rotation, which permits us to calculate the edge correlation functions analytically. We demonstrate that the two edge correlation functions can be used to characterize the trivial, Su-Schrieffer-Heeger-like topological and topological superconductor phases of both the noninteracting and interacting systems and give their phase diagrams.
Helmholtz bright and boundary solitons

Energy Technology Data Exchange (ETDEWEB)

Christian, J M [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); McDonald, G S [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); Chamorro-Posada, P [Departmento de TeorIa de la Senal y Comunicaciones e IngenierIa Telematica, Universidad de Valladolid, ETSI Telecomunicacion, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)

2007-02-16

We report, for the first time, exact analytical boundary solitons of a generalized cubic-quintic nonlinear Helmholtz (NLH) equation. These solutions have a linked-plateau topology that is distinct from conventional dark soliton solutions; their amplitude and intensity distributions are spatially delocalized and connect regions of finite and zero wave-field disturbances (suggesting also the classification as 'edge solitons'). Extensive numerical simulations compare the stability properties of recently derived Helmholtz bright solitons, for this type of polynomial nonlinearity, to those of the new boundary solitons. The latter are found to possess a remarkable stability characteristic, exhibiting robustness against perturbations that would otherwise lead to the destabilizing of their bright-soliton counterparts.
Prosodic Transfer in Learner and Contact Varieties: Speech Rhythm and Intonation of Buenos Aires Spanish and L2 Castilian Spanish Produced by Italian Native Speakers

Science.gov (United States)

Gabriel, Christoph; Kireva, Elena

2014-01-01

A remarkable example of Spanish-Italian contact is the Spanish variety spoken in Buenos Aires (Porteño), which is said to be prosodically "Italianized" due to migration-induced contact. The change in Porteño prosody has been interpreted as a result of transfer from the first language (L1) that occurred when Italian immigrants learned…
A survey of problems in divertor and edge plasma theory

International Nuclear Information System (INIS)

Boozer, A.; Braams, B.; Weitzner, H.; Hazeltine, R.; Houlberg, W.; Oktay, E.; Sadowski, W.; Wootton, A.

1992-01-01

Theoretical physics problems related to divertor design are presented, organized by the region in which they occur. Some of the open questions in edge physics are presented from a theoretician's point of view. After a cursory sketch of the fluid models of the edge plasma and their numerical realization, the following topics are taken up: time-dependent problems, non-axisymmetric effects, anomalous transport in the scrape-off layer, edge kinetic theory, sheath effects and boundary conditions in divertors, electric field effects, atomic and molecular data issues, impurity transport in the divertor region, poloidally localized power dissipation (MARFEs and dense gas targets), helium ash removal, and neutral transport. The report ends with a summary of selected problems of particular significance and a brief bibliography of survey articles and related conference proceedings
Flight Investigation of the Low-Speed Characteristics of a 45 deg Swept-Wing Fighter-Type Airplane with Blowing Boundary-Layer Control Applied to the Leading- and Trailing-Edge Flaps

Science.gov (United States)

Quigley, Hervey C.; Anderson, Seth B.; Innis, Robert C.

1960-01-01

A flight investigation has been conducted to study how pilots use the high lift available with blowing-type boundary-layer control applied to the leading- and trailing-edge flaps of a 45 deg. swept-wing airplane. The study includes documentation of the low-speed handling qualities as well as the pilots' evaluations of the landing-approach characteristics. All the pilots who flew the airplane considered it more comfortable to fly at low speeds than any other F-100 configuration they had flown. The major improvements noted were the reduced stall speed, the improved longitudinal stability at high lift, and the reduction in low-speed buffet. The study has shown the minimum comfortable landing-approach speeds are between 120.5 and 126.5 knots compared to 134 for the airplane with a slatted leading edge and the same trailing-edge flap. The limiting factors in the pilots' choices of landing-approach speeds were the limits of ability to control flight-path angle, lack of visibility, trim change with thrust, low static directional stability, and sluggish longitudinal control. Several of these factors were found to be associated with the high angles of attack, between 13 deg. and 15 deg., required for the low approach speeds. The angle of attack for maximum lift coefficient was 28 deg.
Evaluation of potential substrates for restenosis and thrombosis in overlapped versus edge-to-edge juxtaposed bioabsorbable scaffolds: Insights from a computed fluid dynamic study.

Science.gov (United States)

Rigatelli, Gianluca; Zuin, Marco; Dell'Avvocata, Fabio; Cardaioli, Paolo; Vassiliev, Dobrin; Ferenc, Miroslaw; Nghia, Nguyen Tuan; Nguyen, Thach; Foin, Nicholas

2018-04-01

Multiple BRSs and specifically the Absorb scaffold (BVS) (Abbott Vascular, Santa Clara, CA USA) have been often used to treat long diffuse coronary artery lesions. We evaluate by a computational fluid dynamic(CFD) study the impact on the intravascular fluid rheology on multiple bioabsorbable scaffolds (BRS) by standard overlapping versus edge-to-edge technique. We simulated the treatment of a real long significant coronary lesion (>70% luminal narrowing) involving the left anterior descending artery (LAD) treated with a standard or edge-to-edge technique, respectively. Simulations were performed after BVS implantations in two different conditions: 1) Edge-to-edge technique, where the scaffolds are kissed but not overlapped resulting in a luminal encroachment of 0.015cm (150μm); 2) Standard overlapping, where the scaffolds are overlapped resulting in a luminal encroachment of 0.030cm (300μm). After positioning the BVS across the long lesion, the implantation procedure was performed in-silico following all the usual procedural steps. Analysis of the wall shear stress (WSS) suggested that at the vessel wall level the WSS were lower in the overlapping zones overlapping compared to the edge-to-edge zone (∆=0.061Pa, p=0.01). At the struts level the difference between the two WSS was more striking (∆=1.065e-004 p=0.01) favouring the edge-to-edge zone. Our study suggested that at both vessel wall and scaffold struts levels, there was lowering WSS when multiple BVS were implanted with the standard overlapping technique compared to the "edge-to-edge" technique. This lower WSS might represent a substrate for restenosis, early and late BVS thrombosis, potentially explaining at least in part the recent evidences of devices poor performance. Copyright © 2017 Elsevier Inc. All rights reserved.
Habitat edges have weak effects on duck nest survival at local spatial scales

Science.gov (United States)

Raquel, Amelia J; Ringelman, Kevin M.; Ackerman, Joshua T.; Eadie, John M.

2015-01-01

Edge effects on nesting success have been documented in breeding birds in a variety of contexts, but there is still uncertainty in how edge type and spatial scale determine the magnitude and detectability of edge effects. Habitat edges are often viewed as predator corridors that surround or penetrate core habitat and increase the risk of predation for nearby nests. We studied the effects of three different types of potential predator corridors (main perimeter roads, field boundaries, and ATV trails within fields) on waterfowl nest survival in California. We measured the distance from duck nests to the nearest edge of each type, and used distance as a covariate in a logistic exposure analysis of nest survival. We found only weak evidence for edge effects due to predation. The best supported model of nest survival included all three distance categories, and while all coefficient estimates were positive (indicating that survival increased with distance from edge), 85% coefficient confidence intervals approached or bounded zero indicating an overall weak effect of habitat edges on nest success. We suggest that given the configuration of edges at our site, there may be few areas far enough from hard edges to be considered ‘core’ habitat, making edge effects on nest survival particularly difficult to detect.
Flow Control Over Sharp-Edged Wings

Science.gov (United States)

2007-07-01

Gad-el-Hak (2001) as the ability to actively or passively manipulate a flow field to effect a desired change. The challenge is to achieve that change...combinations. Been able to independently control both is a great challenge . These requirements may appear too stringent for the sharp- edged airfoils...06 0𔄁 08 09 lic Vlc Figure 22: Pressure distributions for Model B at a=13 °. Stations I (left); 2 (right) 1 , -2 1 F - [12 1 -6a -16 08 -08 06 -06
Sensitivity of quantum walks to a boundary of two-dimensional lattices: approaches based on the CGMV method and topological phases

International Nuclear Information System (INIS)

Endo, Takako; Konno, Norio; Obuse, Hideaki; Segawa, Etsuo

2017-01-01

In this paper, we treat quantum walks in a two-dimensional lattice with cutting edges along a straight boundary introduced by Asboth and Edge (2015 Phys. Rev . A 91 022324) in order to study one-dimensional edge states originating from topological phases of matter and to obtain collateral evidence of how a quantum walker reacts to the boundary. Firstly, we connect this model to the CMV matrix, which provides a 5-term recursion relation of the Laurent polynomial associated with spectral measure on the unit circle. Secondly, we explicitly derive the spectra of bulk and edge states of the quantum walk with the boundary using spectral analysis of the CMV matrix. Thirdly, while topological numbers of the model studied so far are well-defined only when gaps in the bulk spectrum exist, we find a new topological number defined only when there are no gaps in the bulk spectrum. We confirm that the existence of the spectrum for edge states derived from the CMV matrix is consistent with the prediction from a bulk-edge correspondence using topological numbers calculated in the cases where gaps in the bulk spectrum do or do not exist. Finally, we show how the edge states contribute to the asymptotic behavior of the quantum walk through limit theorems of the finding probability. Conversely, we also propose a differential equation using this limit distribution whose solution is the underlying edge state. (paper)
Stability of hypersonic boundary-layer flows with chemistry

Science.gov (United States)

Reed, Helen L.; Stuckert, Gregory K.; Haynes, Timothy S.

1993-01-01

The effects of nonequilibrium chemistry and three dimensionality on the stability characteristics of hypersonic flows are discussed. In two-dimensional (2-D) and axisymmetric flows, the inclusion of chemistry causes a shift of the second mode of Mack to lower frequencies. This is found to be due to the increase in size of the region of relative supersonic flow because of the lower speeds of sound in the relatively cooler boundary layers. Although this shift in frequency is present in both the equilibrium and nonequilibrium air results, the equilibrium approximation predicts modes which are not observed in the nonequilibrium calculations (for the flight conditions considered). These modes are superpositions of incoming and outgoing unstable disturbances which travel supersonically relative to the boundary-layer edge velocity. Such solutions are possible because of the finite shock stand-off distance. Their corresponding wall-normal profiles exhibit an oscillatory behavior in the inviscid region between the boundary-layer edge and the bow shock. For the examination of three-dimensional (3-D) effects, a rotating cone is used as a model of a swept wing. An increase of stagnation temperature is found to be only slightly stabilizing. The correlation of transition location (N = 9) with parameters describing the crossflow profile is discussed. Transition location does not correlate with the traditional crossflow Reynolds number. A new parameter that appears to correlate for boundary-layer flow was found. A verification with experiments on a yawed cone is provided.
Study on impurity screening in stochastic magnetic boundary of the Large Helical Device

International Nuclear Information System (INIS)

Kobayashi, M.; Morita, S.; Feng, Y.

2008-10-01

The impurity transport characteristics in the scrape-off layer associated with a stochastic magnetic boundary of LHD are analyzed. The remnant islands with very small internal field line pitch in the stochastic region play a key role in reducing the impurity influx. The thermal force driven impurity influx is significantly suppressed when the perpendicular energy flux exceeds the parallel one inside the islands due to the small pitch. Application of the 3D edge transport code, EMC3-EIRENE, confirmed the impurity retention (screening) effect in the edge region. It is also found that the edge surface layers are the most effective region to retain (screen) impurities because of the flow acceleration and plasma cooling via short flux tubes. The carbon emission obtained in experiments is in good agreement with the modelling results, showing the impurity retention (screening) potential of the stochastic magnetic boundary. (author)
The edge of entanglement: getting the boundary right for non-minimally coupled scalar fields

Energy Technology Data Exchange (ETDEWEB)

Herzog, Christopher P. [C.N. Yang Institute for Theoretical Physics,Department of Physics and Astronomy, Stony Brook University,Stony Brook, NY 11794 (United States); Nishioka, Tatsuma [Department of Physics, Faculty of Science, The University of Tokyo,Bunkyo-ku, Tokyo 113-0033 (Japan)

2016-12-27

In entanglement computations for a free scalar field with coupling to background curvature, there is a boundary term in the modular Hamiltonian which must be correctly specified in order to get sensible results. We focus here on the entanglement in flat space across a planar interface and (in the case of conformal coupling) other geometries related to this one by Weyl rescaling of the metric. For these “half-space entanglement” computations, we give a new derivation of the boundary term and revisit how it clears up a number of puzzles in the literature, including mass corrections and twist operator dimensions. We also discuss how related boundary terms may show up in other field theories.
D0 data processing within EDG/LCG

International Nuclear Information System (INIS)

Harenberg, Torsten; Wuppertal U.; Bos, Kors; NIKHEF, Amsterdam; Byrom, Rob; Fisher, Steve; Rutherford; Groep, David; van Leeuwen, Willem; NIKHEF, Amsterdam; Mattig, Peter; Wuppertal U.; Templon, Jeff; NIKHEF, Amsterdam

2004-01-01

In September 2003, the D0 experiment at TEvatron has launched a reprocessing effort. In total 519,212,822 of the experiment's events have been reprocessed to use the new perceptions of the detector's behavior. Out of these events 97,619,114 have been reprocessed at remote sites. For the first time, the European DataGRID has been used to re-process a part of these events as an evaluation of the EDG application testbed. They used EDG's own R-GMA database for monitoring and bookkeeping and constructed four tables: (1) submission table--records the submission of jobs to the Resource Broker; (2) job start table--holds the time the job started on a Worker Node together with process ID and many more; (3) job end table--information is published immediately before the job stops; and (4) command table--a command list table for debugging purposes. As D0 has its own data management system called ''SAM'', some sort of channel between SAM and the EDG data management system is required. The approach used is shown to the left, were a certain storage area, physically present on a back-end server machine, is visible both from a SAM-enabled machine (''SAM station'') and from EDG machines at the same site. This has bene achieved at NIKHEF. The D0 software has been adapted to run in the EDG framework. Only a few changes has to be made. Missing libraries were included and some extra packages were shipped (pyxml and Python 2.1). However, arounding wrapper scripts were written to handle the in- and output and put/get it from/to EDG's Data Management System (DMS)
Trans-Boundary Edge Effects in the Western Carpathians: The Influence of Hunting on Large Carnivore Occupancy

Science.gov (United States)

Váňa, Martin; Suchomel, Josef; Chapron, Guillaume; López-Bao, José Vicente

2016-01-01

The conservation and management of wolves Canis lupus in the periphery of their distribution is challenging. Edges of wolf distribution are characterized by very few and intermittent occurrences of individuals, which are modulated by multiple factors affecting the overall population such as human-caused mortality, management targets and food availability. The knowledge of population dynamics in the edges becomes crucial when hunting takes place nearby the edges, which may preclude population expansion. Here, using as example the occurrence of wolves in the Beskydy Mountains (Czech-Slovak border), which are the edge distribution of the wolf and Eurasian lynx Lynx lynx populations in the West Carpathians, we explored how food availability and hunting in the Slovakian core area affected the dynamics of wolves in the edges of this population. During 2003–2012, we monitored large carnivore occurrence by snow-tracking surveys and tested potential differences in the occurrence of these species in Beskydy Mountains and potential mechanisms behind detected patterns. Despite the proximity to the core area, with several wolf reproductions being confirmed at least in recent years, the wolf was a very rare species in Beskydy and was recorded 14 times less often than the lynx. The expected abundance of wolves in the Beskydy Mountains was inversely related to prey availability in the Slovakian core area. Wolf hunting the year before influenced the expected abundance of wolves in Beskydy area. We discuss how different life histories and legal status of both species probably account for most of the observed difference of occurrence at range margins. PMID:28002475

Trans-Boundary Edge Effects in the Western Carpathians: The Influence of Hunting on Large Carnivore Occupancy.

Science.gov (United States)

Kutal, Miroslav; Váňa, Martin; Suchomel, Josef; Chapron, Guillaume; López-Bao, José Vicente

2016-01-01

The conservation and management of wolves Canis lupus in the periphery of their distribution is challenging. Edges of wolf distribution are characterized by very few and intermittent occurrences of individuals, which are modulated by multiple factors affecting the overall population such as human-caused mortality, management targets and food availability. The knowledge of population dynamics in the edges becomes crucial when hunting takes place nearby the edges, which may preclude population expansion. Here, using as example the occurrence of wolves in the Beskydy Mountains (Czech-Slovak border), which are the edge distribution of the wolf and Eurasian lynx Lynx lynx populations in the West Carpathians, we explored how food availability and hunting in the Slovakian core area affected the dynamics of wolves in the edges of this population. During 2003-2012, we monitored large carnivore occurrence by snow-tracking surveys and tested potential differences in the occurrence of these species in Beskydy Mountains and potential mechanisms behind detected patterns. Despite the proximity to the core area, with several wolf reproductions being confirmed at least in recent years, the wolf was a very rare species in Beskydy and was recorded 14 times less often than the lynx. The expected abundance of wolves in the Beskydy Mountains was inversely related to prey availability in the Slovakian core area. Wolf hunting the year before influenced the expected abundance of wolves in Beskydy area. We discuss how different life histories and legal status of both species probably account for most of the observed difference of occurrence at range margins.
Code-code comparisons of DIVIMP's 'onion-skin model' and the EDGE2D fluid code

International Nuclear Information System (INIS)

Stangeby, P.C.; Elder, J.D.; Horton, L.D.; Simonini, R.; Taroni, A.; Matthews, O.F.; Monk, R.D.

1997-01-01

In onion-skin modelling, O-SM, of the edge plasma, the cross-field power and particle flows are treated very simply e.g. as spatially uniform. The validity of O-S modelling requires demonstration that such approximations can still result in reasonable solutions for the edge plasma. This is demonstrated here by comparison of O-SM with full 2D fluid edge solutions generated by the EDGE2D code. The target boundary conditions for the O-SM are taken from the EDGE2D output and the complete O-SM solutions are then compared with the EDGE2D ones. Agreement is generally within 20% for n e , T e , T i and parallel particle flux density Γ for the medium and high recycling JET cases examined and somewhat less good for a strongly detached CMOD example. (orig.)
The significance of a grassy field boundary for the spatial distribution of carabids within two cereal fields

NARCIS (Netherlands)

Saska, P.; Vodde, M.; Heijerman, Th.; Westerman, P.R.; Werf, van der W.

2007-01-01

This paper investigated how distance from the field edge affects overall activity-density, species richness and distribution of individual carabid (Coleoptera: Carabidae) species. Carabid beetles were sampled using pitfall traps at six different locations: grassy field boundary, 0 (field edge), 4,
Neurology of Affective Prosody and Its Functional-Anatomic Organization in Right Hemisphere

Science.gov (United States)

Ross, Elliott D.; Monnot, Marilee

2008-01-01

Unlike the aphasic syndromes, the organization of affective prosody in brain has remained controversial because affective-prosodic deficits may occur after left or right brain damage. However, different patterns of deficits are observed following left and right brain damage that suggest affective prosody is a dominant and lateralized function of…
Conservation of boundary extension mechanisms between plants and animals

OpenAIRE

Mathur, Jaideep

2005-01-01

Locomotion clearly sets plants and animals apart. However, recent studies in higher plants reveal cell-biological and molecular features similar to those observed at the leading edge of animal cells and suggest conservation of boundary extension mechanisms between motile animal cells and nonmotile plant cells.
Effect of gender on results of percutaneous edge-to-edge mitral valve repair with MitraClip system.

Science.gov (United States)

Estévez-Loureiro, Rodrigo; Settergren, Magnus; Winter, Reidar; Jacobsen, Per; Dall'Ara, Gianni; Sondergaard, Lars; Cheung, Gary; Pighi, Michele; Ghione, Matteo; Ihlemann, Nikolaj; Moat, Neil E; Price, Susanna; Streit Rosenberg, Tine; Di Mario, Carlo; Franzen, Olaf

2015-07-15

Knowledge regarding gender-specific results of percutaneous edge-to-edge mitral valve repair is scarce. The aim of this study was to investigate gender differences in outcomes in a cohort of patients treated with MitraClip implantation. A multicenter registry of 173 patients treated with MitraClip prostheses from 2009 to 2012 at 3 experienced centers was performed. One hundred nine patients (63%) were men. Men were younger (mean age 73 ± 10 vs 79 ± 9 years, p = 0.001) and had a higher prevalence of previous coronary bypass graft surgery (34% vs 13%, p = 0.002), previous myocardial infarction (46% vs 20%, p = 0.001), and diabetes mellitus (26% vs 11%, p = 0.020). There were no differences regarding New York Heart Association (NYHA) functional class before the intervention (NYHA class III or IV in 95% of men vs 97% of women, p = 0.472) or the cause of mitral regurgitation (MR) (functional in 58% of men vs 48% of women, p = 0.233). Men exhibited significantly larger ventricles (mean indexed left ventricular end-systolic diameter 2.4 ± 0.8 vs 2.0 ± 1.6 cm/m(2), p = 0.002, and mean indexed left ventricular end-diastolic volume 92.7 ± 46.1 vs 59.9 ± 24.6 ml/m(2), p effective treatment of MR in men and women. Copyright © 2015 Elsevier Inc. All rights reserved.
Flow tilt angles near forest edges - Part 1: Sonic anemometry

DEFF Research Database (Denmark)

Dellwik, Ebba; Mann, Jakob; Larsen, Klaus Steenberg

2010-01-01

distortion and vertical alignment, it was only possible to a limited extent to relate sonic anemometer flow tilt angles to upwind forest edges, but the results by the lidar indicated that an internal boundary layer affect flow tilt angles at 21m above the forest. This is in accordance with earlier studies......-flow angles were assumed for neutral flow, the data was interpreted in relation to upstream and downstream forest edges. Uncertainties caused by flow distortion, vertical misalignment and limited sampling time (statistical uncertainty) were evaluated and found to be highly significant. Since the attack angle...... balance, unless all terms in the carbon dioxide conservation equation can be precisely estimated....
Living on the edge: a toy model for holographic reconstruction of algebras with centers

Energy Technology Data Exchange (ETDEWEB)

Donnelly, William; Marolf, Donald; Michel, Ben; Wien, Jason [Department of Physics, University of California,Santa Barbara, CA 93106 (United States)

2017-04-18

We generalize the Pastawski-Yoshida-Harlow-Preskill (HaPPY) holographic quantum error-correcting code to provide a toy model for bulk gauge fields or linearized gravitons. The key new elements are the introduction of degrees of freedom on the links (edges) of the associated tensor network and their connection to further copies of the HaPPY code by an appropriate isometry. The result is a model in which boundary regions allow the reconstruction of bulk algebras with central elements living on the interior edges of the (greedy) entanglement wedge, and where these central elements can also be reconstructed from complementary boundary regions. In addition, the entropy of boundary regions receives both Ryu-Takayanagi-like contributions and further corrections that model the ((δArea)/(4G{sub N})) term of Faulkner, Lewkowycz, and Maldacena. Comparison with Yang-Mills theory then suggests that this ((δArea)/(4G{sub N})) term can be reinterpreted as a part of the bulk entropy of gravitons under an appropriate extension of the physical bulk Hilbert space.
Living on the edge: a toy model for holographic reconstruction of algebras with centers

International Nuclear Information System (INIS)

Donnelly, William; Marolf, Donald; Michel, Ben; Wien, Jason

2017-01-01

We generalize the Pastawski-Yoshida-Harlow-Preskill (HaPPY) holographic quantum error-correcting code to provide a toy model for bulk gauge fields or linearized gravitons. The key new elements are the introduction of degrees of freedom on the links (edges) of the associated tensor network and their connection to further copies of the HaPPY code by an appropriate isometry. The result is a model in which boundary regions allow the reconstruction of bulk algebras with central elements living on the interior edges of the (greedy) entanglement wedge, and where these central elements can also be reconstructed from complementary boundary regions. In addition, the entropy of boundary regions receives both Ryu-Takayanagi-like contributions and further corrections that model the ((δArea)/(4G N )) term of Faulkner, Lewkowycz, and Maldacena. Comparison with Yang-Mills theory then suggests that this ((δArea)/(4G N )) term can be reinterpreted as a part of the bulk entropy of gravitons under an appropriate extension of the physical bulk Hilbert space.
Boundary layer effects on the vortex shedding in a Donaldson- type hydrofoil

International Nuclear Information System (INIS)

Fontanals, A; Guardo, A; Egusquiza, E; Zobeiri, A; Farhat, M; Avellan, F

2014-01-01

Fluid - Structure Interaction (FSI) phenomena is becoming a relevant study field for the design or revamping of hydropower plants. The generalized trend of increasing flow rates and reducing rotor blades/stay vanes thickness in order to improve the efficiency of the machine together with a major push from plant owners/operators for production flexibility (partial load operation is more common nowadays) make the FSI between the vortex shedding phenomenon and the vanes/blades of the machine an area of interest. From a design point of view, the machine structure has to resist all the hydrodynamic forces generated and maintain tension stresses under the fatigue limit to ensure a machine lifetime of several decades. To accomplish that goal, designers have to assure there is no presence of strong coupling phenomena (lock-in) between the vortex shedding frequency and the eigenfrequencies of the structure. As the vortex street is directly related to the state of the boundary layer along the hydrofoil, in this paper the effect of the boundary layer on the vortex shedding in a Donaldson-type hydrofoil is studied using Computational Fluid Dynamics (CFD). The development of the boundary layer along the Donaldson trailing edge hydrofoil chord is presented under lock-off conditions. The results are validated against previously obtained experimental results. Since the Donaldson trailing edge is non-symmetric, the boundary layer velocity profiles are reported for the suction and pressure side of the hydrofoil. In addition, the effect of the Donaldson trailing edge on laminar-to-turbulent transition on both sides of the hydrofoil is studied
Left-right entanglement entropy of Dp-branes

Energy Technology Data Exchange (ETDEWEB)

Zayas, Leopoldo A. Pando [The Abdus Salam International Centre for Theoretical Physics,Strada Costiera 11, 34014 Trieste (Italy); Michigan Center for Theoretical Physics, Randall Laboratory of Physics,The University of Michigan,450 Church Street, Ann Arbor, MI 48109-1120 (United States); Quiroz, Norma [Departamento de Ciencias Exactas, Tecnología y Metodología,Centro Universitario del Sur, Universidad de Guadalajara,Enrique Arreola Silva 883, C.P. 49000, Cd. Guzmán, Jalisco (Mexico)

2016-11-04

We compute the left-right entanglement entropy for Dp-branes in string theory. We employ the CFT approach to string theory Dp-branes, in particular, its presentation as coherent states of the closed string sector. The entanglement entropy is computed as the von Neumann entropy for a density matrix resulting from integration over the left-moving degrees of freedom. We discuss various crucial ambiguities related to sums over spin structures and argue that different choices capture different physics; however, we advance a themodynamic argument that seems to favor a particular choice of replica. We also consider Dp branes on compact dimensions and verify that the effects of T-duality act covariantly on the Dp brane entanglement entropy. We find that generically the left-right entanglement entropy provides a suitable generalization of boundary entropy and of the D-brane tension.
The Extraction of Road Boundary from Crowdsourcing Trajectory Using Constrained Delaunay Triangulation

Directory of Open Access Journals (Sweden)

YANG Wei

2017-02-01

Full Text Available Extraction of road boundary accurately from crowdsourcing trajectory lines is still a hard work.Therefore,this study presented a new approach to use vehicle trajectory lines to extract road boundary.Firstly, constructing constrained Delaunay triangulation within interpolated track lines to calculate road boundary descriptors using triangle edge length and Voronoi cell.Road boundary recognition model was established by integrating the two boundary descriptors.Then,based on seed polygons,a regional growing method was proposed to extract road boundary. Finally, taxi GPS traces in Beijing were used to verify the validity of the novel method, and the results also showed that our method was suitable for GPS traces with disparity density,complex road structure and different time interval.
Gap states and edge properties of rectangular graphene quantum dot in staggered potential

Science.gov (United States)

Jeong, Y. H.; Eric Yang, S.-R.

2017-09-01

We investigate edge properties of a gapful rectangular graphene quantum dot in a staggered potential. In such a system gap states with discrete and closely spaced energy levels exist that are spatially located on the left or right zigzag edge. We find that, although the bulk states outside the energy gap are nearly unaffected, spin degeneracy of each gap state is lifted by the staggered potential. We have computed the occupation numbers of spin-up and -down gap states at various values of the strength of the staggered potential. The electronic and magnetic properties of the zigzag edges depend sensitively on these numbers. We discuss the possibility of applying this system as a single electron spintronic device.
The effective action for edge states in higher-dimensional quantum Hall systems

International Nuclear Information System (INIS)

Karabali, Dimitra; Nair, V.P.

2004-01-01

We show that the effective action for the edge excitations of a quantum Hall droplet of fermions in higher dimensions is generically given by a chiral bosonic action. We explicitly analyze the quantum Hall effect on complex projective spaces CP k , with a U(1) background magnetic field. The edge excitations are described by Abelian bosonic fields on S 2k-1 with only one spatial direction along the boundary of the droplet relevant for the dynamics. Our analysis also leads to an action for edge excitations for the case of the Zhang-Hu four-dimensional quantum Hall effect defined on S 4 with an SU(2) background magnetic field, using the fact that CP 3 is an S 2 -bundle over S 4
Bilayer graphene: gap tunability and edge properties

International Nuclear Information System (INIS)

Castro, Eduardo V; Santos, J M B Lopes dos; Peres, N M R; Guinea, F; Castro Neto, A H

2008-01-01

Bilayer graphene - two coupled single graphene layers stacked as in graphite - provides the only known semiconductor with a gap that can be tuned externally through electric field effect. Here we use a tight binding approach to study how the gap changes with the applied electric field. Within a parallel plate capacitor model and taking into account screening of the external field, we describe real back gated and/or chemically doped bilayer devices. We show that a gap between zero and midinfrared energies can be induced and externally tuned in these devices, making bilayer graphene very appealing from the point of view of applications. However, applications to nanotechnology require careful treatment of the effect of sample boundaries. This being particularly true in graphene, where the presence of edge states at zero energy - the Fermi level of the undoped system - has been extensively reported. Here we show that also bilayer graphene supports surface states localized at zigzag edges. The presence of two layers, however, allows for a new type of edge state which shows an enhanced penetration into the bulk and gives rise to band crossing phenomenon inside the gap of the biased bilayer system.
Immersed boundary simulation of flow through arterial junctions

Indian Academy of Sciences (India)

Dwaipayan Sarkar

haemodynamic activities in regions like carotid arteries, encephalic regions and ... immersed boundary method (IBM), has gained attention in the last few years .... the flow from left inlet and the flow is subsequently divided among the two ...
Fundamental solutions and dual boundary element methods for fracture in plane Cosserat elasticity.

Science.gov (United States)

Atroshchenko, Elena; Bordas, Stéphane P A

2015-07-08

In this paper, both singular and hypersingular fundamental solutions of plane Cosserat elasticity are derived and given in a ready-to-use form. The hypersingular fundamental solutions allow to formulate the analogue of Somigliana stress identity, which can be used to obtain the stress and couple-stress fields inside the domain from the boundary values of the displacements, microrotation and stress and couple-stress tractions. Using these newly derived fundamental solutions, the boundary integral equations of both types are formulated and solved by the boundary element method. Simultaneous use of both types of equations (approach known as the dual boundary element method (BEM)) allows problems where parts of the boundary are overlapping, such as crack problems, to be treated and to do this for general geometry and loading conditions. The high accuracy of the boundary element method for both types of equations is demonstrated for a number of benchmark problems, including a Griffith crack problem and a plate with an edge crack. The detailed comparison of the BEM results and the analytical solution for a Griffith crack and an edge crack is given, particularly in terms of stress and couple-stress intensity factors, as well as the crack opening displacements and microrotations on the crack faces and the angular distributions of stresses and couple-stresses around the crack tip.
Formation of Stone-Wales edge: Multistep reconstruction and growth mechanisms of zigzag nanographene.

Science.gov (United States)

Dang, Jing-Shuang; Wang, Wei-Wei; Zheng, Jia-Jia; Nagase, Shigeru; Zhao, Xiang

2017-10-05

Although the existence of Stone-Wales (5-7) defect at graphene edge has been clarified experimentally, theoretical study on the formation mechanism is still imperfect. In particular, the regioselectivity of multistep reactions at edge (self-reconstruction and growth with foreign carbon feedstock) is essential to understand the kinetic behavior of reactive boundaries but investigations are still lacking. Herein, by using finite-sized models, multistep reconstructions and carbon dimer additions of a bared zigzag edge are introduced using density functional theory calculations. The zigzag to 5-7 transformation is proved as a site-selective process to generate alternating 5-7 pairs sequentially and the first step with largest barrier is suggested as the rate-determining step. Conversely, successive C 2 insertions on the active edge are calculated to elucidate the formation of 5-7 edge during graphene growth. A metastable intermediate with a triple sequentially fused pentagon fragment is proved as the key structure for 5-7 edge formation. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Suppression of large edge localized modes in high confinement DIII-D plasmas with a stochastic magnetic boundary

Energy Technology Data Exchange (ETDEWEB)

Evans, T.E. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)]. E-mail: evans@fusion.gat.com; Moyer, R.A. [University of California at San Diego, La Jolla, CA 92093-0417 (United States); Watkins, J.G. [Sandia National Laboratories, Albuquerque, NM 87185-1129 (United States); Thomas, P.R. [Association Euratom-CEA, CEA Cadarache, F-13108, St. Paul-lez-Durance (France); Osborne, T.H. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Boedo, J.A. [University of California at San Diego, La Jolla, CA 92093-0417 (United States); Fenstermacher, M.E. [Lawrence Livermore National Laborabory, Livermore, CA 94550 (United States); Finken, K.H. [Forschungszentrum Juelich, Institute for Plasma Physics, D52425 Juelich (Germany); Groebner, R.J. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Groth, M. [Lawrence Livermore National Laborabory, Livermore, CA 94550 (United States); Harris, J. [Australian National University, Canberra (Australia); Jackson, G.L. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Haye, R.J. La [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Lasnier, C.J. [Lawrence Livermore National Laborabory, Livermore, CA 94550 (United States); Schaffer, M.J. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Wang, G. [University of California, Los Angeles, California (United States); Zeng, L. [University of California, Los Angeles, California (United States)

2005-03-01

Large 70 Hz Type-I edge localized modes (ELMs) are converted into small 130 Hz oscillations using edge resonant magnetic perturbations (RMPs) from a coil with currents 0.4% I {sub p} in double null DIII-D plasmas. When the RMP is properly phased with respect to the background field errors, all but a few isolated ELM-like events are suppressed. The impulsive pedestal energy loss {delta}E {sub ELM}/{delta}t {sup 1/2} to the scrape-of layer is reduced a factor of 20 relative to the Type-I ELMs and the core confinement is unaffected by the perturbation field. Significant changes in the properties of the ELMs are also observed when edge RMPs are applied to lower single null plasmas but the nature of these changes are much more complex. Both lower single null and double null plasmas are being studied to determine how ELM control techniques based on the application of edge RMPs can be expected to scale to future devices such as ITER.
Development of polygon elements based on the scaled boundary finite element method

International Nuclear Information System (INIS)

Chiong, Irene; Song Chongmin

2010-01-01

We aim to extend the scaled boundary finite element method to construct conforming polygon elements. The development of the polygonal finite element is highly anticipated in computational mechanics as greater flexibility and accuracy can be achieved using these elements. The scaled boundary polygonal finite element will enable new developments in mesh generation, better accuracy from a higher order approximation and better transition elements in finite element meshes. Polygon elements of arbitrary number of edges and order have been developed successfully. The edges of an element are discretised with line elements. The displacement solution of the scaled boundary finite element method is used in the development of shape functions. They are shown to be smooth and continuous within the element, and satisfy compatibility and completeness requirements. Furthermore, eigenvalue decomposition has been used to depict element modes and outcomes indicate the ability of the scaled boundary polygonal element to express rigid body and constant strain modes. Numerical tests are presented; the patch test is passed and constant strain modes verified. Accuracy and convergence of the method are also presented and the performance of the scaled boundary polygonal finite element is verified on Cook's swept panel problem. Results show that the scaled boundary polygonal finite element method outperforms a traditional mesh and accuracy and convergence are achieved from fewer nodes. The proposed method is also shown to be truly flexible, and applies to arbitrary n-gons formed of irregular and non-convex polygons.

Impact ejecta at the Paleocene-Eocene boundary.

Science.gov (United States)

Schaller, Morgan F; Fung, Megan K; Wright, James D; Katz, Miriam E; Kent, Dennis V

2016-10-14

Extraterrestrial impacts have left a substantial imprint on the climate and evolutionary history of Earth. A rapid carbon cycle perturbation and global warming event about 56 million years ago at the Paleocene-Eocene (P-E) boundary (the Paleocene-Eocene Thermal Maximum) was accompanied by rapid expansions of mammals and terrestrial plants and extinctions of deep-sea benthic organisms. Here, we report the discovery of silicate glass spherules in a discrete stratigraphic layer from three marine P-E boundary sections on the Atlantic margin. Distinct characteristics identify the spherules as microtektites and microkrystites, indicating that an extraterrestrial impact occurred during the carbon isotope excursion at the P-E boundary. Copyright © 2016, American Association for the Advancement of Science.
Code improvements and applications of a two-dimensional edge plasma model for toroidal devices

International Nuclear Information System (INIS)

Baelmans, M.

1994-03-01

This thesis focuses mainly on plasma behaviour in boundary layers of magnetically confined plasmas. Increasing emphasis has been put on edge studies during the last decade, as it became evident that some aspects of Tokamak operations are largely controlled, or even dominated, by edge processes. Therefore, the motivation for this research is to improve understanding of plasma behaviour in general, and edge plasma behaviour in particular, firstly in present experiments, and also to predict edge plasma conditions in future nuclear fusion devices. In a first section some fundamental concepts and principles of controlled fusion are described. Two different types of plasma confinement concepts which have promising features with regard to the above mentioned goal are outlined in a next section, 1.2. In section 1.3 an introduction to plasma edge phenomena is given. In a last section, 1.4, the outline of the thesis is described. (orig.)
Analysis of Windward Side Hypersonic Boundary Layer Transition on Blunted Cones at Angle of Attack

Science.gov (United States)

2017-01-09

correlated with PSE/LST N-Factors. 15. SUBJECT TERMS boundary layer transition, hypersonic, ground test 16. SECURITY CLASSIFICATION OF: 17. LIMITATION ...Maccoll) solution e condition at boundary layer edge w condition at wall, viscous ∞ condition in freestream Conventions LST Linear Stability Theory PSE...STATES AIR FORCE AFRL-RQ-WP-TP-2017-0169 ANALYSIS OF WINDWARD SIDE HYPERSONIC BOUNDARY LAYER TRANSITION ON BLUNTED CONES AT ANGLE OF ATTACK Roger
On the effect of leading edge blowing on circulation control airfoil aerodynamics

Science.gov (United States)

Mclachlan, B. G.

1987-01-01

In the present context the term circulation control is used to denote a method of lift generation that utilizes tangential jet blowing over the upper surface of a rounded trailing edge airfoil to determine the location of the boundary layer separation points, thus setting an effective Kutta condition. At present little information exists on the flow structure generated by circulation control airfoils under leading edge blowing. Consequently, no theoretical methods exist to predict airfoil performance under such conditions. An experimental study of the flow field generated by a two dimensional circulation control airfoil under steady leading and trailing edge blowing was undertaken. The objective was to fundamentally understand the overall flow structure generated and its relation to airfoil performance. Flow visualization was performed to define the overall flow field structure. Measurements of the airfoil forces were also made to provide a correlation of the observed flow field structure to airfoil performance. Preliminary results are presented, specifically on the effect on the flow field structure of leading edge blowing, alone and in conjunction with trailing edge blowing.
Role of edge effect on small mammal populations in a forest fragment

International Nuclear Information System (INIS)

Wike, L.D.

2000-01-01

In many cases, edge effect may determine the distribution and densities of small mammal populations. In 1995 and 1998, a mark and recapture study was conducted at the Savannah River Site (SRS), Aiken, SC, to evaluate the role of forest edge habitat. The area studied was an abandoned home site that had been recently isolated by a timber harvest. Harvest activities left a distinct edge of old field and planted pine contrasting with a relatively xeric, mixed hardwood stand. Trapping was conducted for 17 days in 1995 and 14 days in 1998. Three 30 m by 150 m grids were placed in the clear-cut, edge, and hardwood interior habitats. For both years the principal species captured were Peromyscus gossypinus, P. polionotus, and Neotoma floridana. The edge habitat accounted for approximately 55 percent of all captures and nearly four times as many recaptures as the interior and clear-cut habitats. In 1998, greater numbers of N. floridana were trapped than in 1995. The results indicate that the use of edge habitat can be pronounced even within simple communities. Stewards of managed or restored habitats need to carefully consider the role of edge in these systems. In managed areas such as waste sites, movement of material within the food chain could be reduced by minimizing edge habitat around the points of contamination
Left passage probability of Schramm-Loewner Evolution

Science.gov (United States)

Najafi, M. N.

2013-06-01

SLE(κ,ρ⃗) is a variant of Schramm-Loewner Evolution (SLE) which describes the curves which are not conformal invariant, but are self-similar due to the presence of some other preferred points on the boundary. In this paper we study the left passage probability (LPP) of SLE(κ,ρ⃗) through field theoretical framework and find the differential equation governing this probability. This equation is numerically solved for the special case κ=2 and hρ=0 in which hρ is the conformal weight of the boundary changing (bcc) operator. It may be referred to loop erased random walk (LERW) and Abelian sandpile model (ASM) with a sink on its boundary. For the curve which starts from ξ0 and conditioned by a change of boundary conditions at x0, we find that this probability depends significantly on the factor x0-ξ0. We also present the perturbative general solution for large x0. As a prototype, we apply this formalism to SLE(κ,κ-6) which governs the curves that start from and end on the real axis.
Thinking out Loud about Teaching Bioethics: A Contribution from the Edge

Science.gov (United States)

Solberg, Mary M.

2005-01-01

Teaching bioethics might be likened to a rollercoaster ride of twists, turns, and dips that invite teachers and students to experience something of their own edges of fear and comfort. Here the author provides readers with a glimpse into her distinctive approach to teaching bioethics that encourages students to move beyond boundaries of personal…
Ablative overlays for Space Shuttle leading edge ascent heat protection

Science.gov (United States)

Strauss, E. L.

1975-01-01

Ablative overlays were evaluated via a plasma-arc simulation of the ascent pulse on the leading edge of the Space Shuttle Orbiter. Overlay concepts included corkboard, polyisocyanurate foam, low-density Teflon, epoxy, and subliming salts. Their densities ranged from 4.9 to 81 lb per cu ft, and the thicknesses varied from 0.107 to 0.330 in. Swept-leading-edge models were fabricated from 30-lb per cu ft silicone-based ablators. The overlays were bonded to maintain the surface temperature of the base ablator below 500 F during ascent. Foams provided minimum-weight overlays, and subliming salts provided minimum-thickness overlays. Teflon left the most uniform surface after ascent heating.
Assessment of stent edge dissections by fractional flow reserve.

Science.gov (United States)

Chung, Ju-Hyun; Ann, Soe Hee; Koo, Bon-Kwon; Nam, Chang-Wook; Doh, Joon-Hyung; Singh, Gillian Balbir; Kim, Hyung Il; Shin, Eun-Seok

2015-04-15

Edge dissections after intervention have been studied with imaging techniques, however, functional assessment has not been studied yet. We investigated the relationship between fractional flow reserve (FFR) and the angiographic type of stent edge dissections and tried to assess the use of FFR-guided management for edge dissection. 51 edge dissections assessed by FFR were included in this prospective observational study. FFR was measured for each type of edge dissection and compared with quantitative coronary angiographic findings. Clinical outcomes were evaluated based on FFR measurements. Edge dissections were classified as type A (47.1%; 24/51), type B (41.2%; 21/51), type C (2.0%; 1/51) and type D (9.8%; 5/51). Mean FFR in type A dissection was 0.87 ± 0.09, in type B 0.86 ± 0.07, in type C 0.72 and in type D 0.57 ± 0.08. All type C and D dissections (6/51) had FFR ≤ 0.8 and were treated with additional stents. Among the 45 type A and B dissections, 8 had a FFR ≤ 0.8 (17.8%), and 50% received additional stenting. All dissections with FFR >0.8 were left untreated except one long dissection case. There was no death, myocardial infarction or target lesion revascularization during hospitalization or the follow-up period (median 152 days; IQR 42-352 days). FFR correlates well with an angiographic type of edge dissection. Angiographic findings are sufficient for deciding the treatment of severe dissections such as types C and D, while FFR-guided management may be safe and effective for mild edge dissections such as types A and B. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
The perception of lexical stress in German: effects of segmental duration and vowel quality in different prosodic patterns.

Science.gov (United States)

Kohler, Klaus J

2012-01-01

Several decades of research, focusing on English, Dutch and German, have set up a hierarchy of acoustic properties for cueing lexical stress. It attributes the strongest cue to criterial-level f0 change, followed by duration, but low weight to energy and to stressed-vowel spectra. This paper re-examines the established view with new data from German. In the natural productions of the German word pair Kaffee 'coffee' - Café 'locality' (with initial vs. final stress in a North German pronunciation), vowel duration was manipulated in a complementary fashion across the two syllables in five steps, spanning the continuum from initial to final stress on each word. The two base words provided different vowel qualities as the second variable, the intervocalic fricative was varied in two values, long and short, taken from Café and Kaffee, and the generated test words were inserted in a low f0 tail and in a high f0 hat-pattern plateau, which both eliminated f0 change as a cue to lexical stress. The sentence stimuli were judged in two listening experiments by 16 listeners in each as to whether the first or the second syllable of the test word was stressed. The results show highly significant effects of vowel duration, vowel quality and fricative duration. The combined vowel-quality and fricative variable can outweigh vowel duration as a cue to lexical stress. The effect of the prosodic frame is only marginal, especially related to a rhythmic factor. The paper concludes that there is no general hierarchy with a fixed ranking of the variables traditionally adduced to signal lexical stress. Every prosodic embedding of segmental sequences defines the hierarchy afresh. Copyright © 2012 S. Karger AG, Basel.
Origin of spin-polarization in edge boron doped zigzag graphene nanoribbon: a potential spin filter.

Science.gov (United States)

Chakrabarty, Soubhik; Wasey, A H M Abdul; Thapa, Ranjit; Das, Gour Prasad

2018-06-04

To realize the graphene based spintronic device the prime challenge is to control the electronic structure of edges. In this work we find the origin of spin filtering property in edge boron doped zigzag graphene nanoribbon (ZGNRs) and provide a guide to prepare the graphene based next generation spin filter based device. Here we unveil the role of orbital (p-electron) to tune the electronic, magnetic and transport properties of the edge B doped ZGNRs. When all the edge carbon atoms at one of the edges of ZGNRs are replaced by B (100% edge B-doping), the system undergoes semiconductor to metal transition. The role of passivation of the edge with single/double atomic hydrogen on the electronic properties and its relation with the p electron is correlated in-depth. 50% edge B-doped ZGNRs (50% of the edge C atoms at one of the edges are replaced by B) also shows half-metallicity when the doped edge is left unpassivated. The half-metallic systems show 100% spin-filtering efficiency for a wide range of bias voltages. Zero bias transmission function of the other configurations shows asymmetric behavior for the up and down spin channels, thereby indicating their possible application potential in nano-spintronics. © 2018 IOP Publishing Ltd.
Edge detection of barium-filled stomach picture by one-dimensional collation method

International Nuclear Information System (INIS)

Nakamura, Shizuo

1983-01-01

The method for the contour edge detection of barium- filled stomach pictures by X-ray for the automatic screening is described using computer technique. It is necessary for the automatic screening of barium- filling pictures to detect accurately the outline of stomachs because the analysis of repletion pictures is performed by checking the disorder of marginal contours and abnormal stomach shapes. However, the detection of the coutour lines is difficult to be successful for the reason that the contrast of stomach pictures to background is low, a stomach is not necessarily filled completely with barium and the shadow of barium flowing into intestines is superimposed on stomach images and the shading is likely to occur. The engineering processing against these problems is not yet solved. In order to reduce the noise due to differential operator, the proposed method determines the boundary of a thing generally by the threshold value of density, and defines the edge of the thing from the differential waveform of density in the vicinity of the boundary. In addition, the method corrects the detection error caused by the local nonconformity of parameters by comparing the edges between the adjacent lines. As a result, in spite of its simple algorithm, the edges with good continuity and less noise can be detected, and the method is not much affected by shading. This method was found to be applicable to the images of others than stomachs. The extraction of the contour of barium- filling pictures requires the high level recognition processing instead of the simple conditioning. (Wakatsuki, Y.)
Influence of slice thickness on the determination of left ventricular wall thickness and dimension by magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Ohnishi, Shusaku; Fukui, Sugao; Atsumi, Chisato and others

1989-02-01

Wall thickness of the ventricular septum and left ventricle, and left ventricular cavity dimension were determined on magnetic resonance (MR) images with slices 5 mm and 10 mm in thickness. Subjects were 3 healthy volunteers and 7 patients with hypertension (4), hypertrophic cardiomyopathy (one) or valvular heart disease (2). In visualizing the cardiac structures such as left ventricular papillary muscle and right and left ventricles, 5 mm-thick images were better than 10 mm-thick images. Edges of ventricular septum and left ventricular wall were more clearly visualized on 5 mm-thick images than 10 mm-thick images. Two mm-thick MR images obtained from 2 patients yielded the most excellent visualization in end-systole, but failed to reveal cardiac structures in detail in end-diastole. Phantom studies revealed no significant differences in image quality of 10 mm and 5 mm in thickness in the axial view 80 degree to the long axis. In the axial view 45 degree to the long axis, 10 mm-thick images were inferior to 5 mm-thick images in detecting the edge of the septum and the left ventricular wall. These results indicate that the selection of slice thickness is one of the most important determinant factors in the measurement of left ventricular wall thickness and cavity dimension. (Namekawa, K).
Influence of slice thickness on the determination of left ventricular wall thickness and dimension by magnetic resonance imaging

International Nuclear Information System (INIS)

Ohnishi, Shusaku; Fukui, Sugao; Atsumi, Chisato

1989-01-01

Wall thickness of the ventricular septum and left ventricle, and left ventricular cavity dimension were determined on magnetic resonance (MR) images with slices 5 mm and 10 mm in thickness. Subjects were 3 healthy volunteers and 7 patients with hypertension (4), hypertrophic cardiomyopathy (one) or valvular heart disease (2). In visualizing the cardiac structures such as left ventricular papillary muscle and right and left ventricles, 5 mm-thick images were better than 10 mm-thick images. Edges of ventricular septum and left ventricular wall were more clearly visualized on 5 mm-thick images than 10 mm-thick images. Two mm-thick MR images obtained from 2 patients yielded the most excellent visualization in end-systole, but failed to reveal cardiac structures in detail in end-diastole. Phantom studies revealed no significant differences in image quality of 10 mm and 5 mm in thickness in the axial view 80 degree to the long axis. In the axial view 45 degree to the long axis, 10 mm-thick images were inferior to 5 mm-thick images in detecting the edge of the septum and the left ventricular wall. These results indicate that the selection of slice thickness is one of the most important determinant factors in the measurement of left ventricular wall thickness and cavity dimension. (Namekawa, K)
Selective Population of Edge States in a 2D Topological Band System.

Science.gov (United States)

Galilo, Bogdan; Lee, Derek K K; Barnett, Ryan

2015-12-11

We consider a system of interacting spin-one atoms in a hexagonal lattice under the presence of a synthetic gauge field. Quenching the quadratic Zeeman field is shown to lead to a dynamical instability of the edge modes. This, in turn, leads to a spin current along the boundary of the system which grows exponentially fast in time following the quench. Tuning the magnitude of the quench can be used to selectively populate edge modes of different momenta. Implications of the intrinsic symmetries of the Hamiltonian on the dynamics are discussed. The results hold for atoms with both antiferromagnetic and ferromagnetic interactions.
Evaluation of global and regional left ventricular function obtained by quantitative gated SPECT using {sup 99m}Tc-tetrofosmin for left ventricular dysfunction

Energy Technology Data Exchange (ETDEWEB)

Ban, Kazunobu; Nakajima, Tohru; Iseki, Harukazu; Abe, Sumihisa; Handa, Shunnosuke; Suzuki, Yutaka [Tokai Univ., Isehara, Kanagawa (Japan). School of Medicine

2000-08-01

The quantitative gated SPECT (QGS) software is able to calculate LV volumes and visualize LV wall motion and perfusion throughout the cardiac cycle using an automatic edge detection algorithm of the left ventricle. We evaluated the reliability of global and regional LV function assessment derived from QGS by comparing it with the results from left ventriculo-cineangiography (LVG). In 20 patients with left ventricular dysfunction who underwent ECG gated {sup 99m}Tc-tetrofosmin SPECT, the end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) were calculated. The QGS-assessed regional wall motion was determined using the cinematic display. QGS-derived EDV, ESV and LVEF correlated well with those by LVG (p<0.001 for each). There was a good correlation between wall motion score (WMS) derived from the QGS and the LVG (r=0.40, p<0.05). In some patients with extensive myocardial infarction, there was a discrepancy in the regional wall motion results between QGS and LVG. The ECG-gated SPECT using QGS is useful to evaluate global and regional LV functions in left ventricular dysfunction. (author)
Boundary Effect of Planar Glow Dielectric Barrier Discharge and Its Influence on the Discharge Structure

International Nuclear Information System (INIS)

Xu Shaowei; Li Lulu; Ouyang Jiting

2015-01-01

The dielectric barrier discharge (DBD) in the glow regime in neon has been investigated by experiment and two-dimensional (2D) fluid modeling. The discharge was carried out in a planar DBD system with segmented-electrodes driven by square-wave voltage. The results show that the glow DBD originates in the center of the electrode and expands outward to the electrode edge during each half cycle of the voltage, forming a radial structure. The discharge decays firstly in the inner area but sustains longer in the edge area, showing a reversed discharge area. The discharge cannot completely cover the entire electrode surface, but remains a border of non- or weak discharge. The fluid modeling shows a similar result in agreement with the experiments. The simulations indicate that the electric field in the edge area is distorted due to the boundary effect so that the electric field and charge distribution are different from that in the inner part. The distorted field reduces the longitudinal component near the edge and causes the local field to be lower than that in the center, and hence makes the discharge behindhand. It also induces a transverse field that makes the discharge extend radially outward to the edge. The boundary effect plays an important role in the glow DBD structure. (paper)
Finite size effects on the helical edge states on the Lieb lattice

International Nuclear Information System (INIS)

Chen Rui; Zhou Bin

2016-01-01

For a two-dimensional Lieb lattice, that is, a line-centered square lattice, the inclusion of the intrinsic spin–orbit (ISO) coupling opens a topologically nontrivial gap, and gives rise to the quantum spin Hall (QSH) effect characterized by two pairs of gapless helical edge states within the bulk gap. Generally, due to the finite size effect in QSH systems, the edge states on the two sides of a strip of finite width can couple together to open a gap in the spectrum. In this paper, we investigate the finite size effect of helical edge states on the Lieb lattice with ISO coupling under three different kinds of boundary conditions, i.e., the straight, bearded and asymmetry edges. The spectrum and wave function of edge modes are derived analytically for a tight-binding model on the Lieb lattice. For a strip Lieb lattice with two straight edges, the ISO coupling induces the Dirac-like bulk states to localize at the edges to become the helical edge states with the same Dirac-like spectrum. Moreover, it is found that in the case with two straight edges the gapless Dirac-like spectrum remains unchanged with decreasing the width of the strip Lieb lattice, and no gap is opened in the edge band. It is concluded that the finite size effect of QSH states is absent in the case with the straight edges. However, in the other two cases with the bearded and asymmetry edges, the energy gap induced by the finite size effect is still opened with decreasing the width of the strip. It is also proposed that the edge band dispersion can be controlled by applying an on-site potential energy on the outermost atoms. (paper)
Spatial and temporal patterns of microclimates at an urban forest edge and their management implications.

Science.gov (United States)

Li, Yingnan; Kang, Wanmo; Han, Yiwen; Song, Youngkeun

2018-01-23

Fragmented forests generate a variety of forest edges, leading to microclimates in the edge zones that differ from those in the forest interior. Understanding microclimatic variation is an important consideration for managers because it helps when making decisions about how to restrict the extent of edge effects. Thus, our study attempted to characterize the changing microclimate features at an urban forest edge located on Mt. Gwanak, Seoul, South Korea. We examined edge effects on air temperature, relative humidity, soil temperature, soil moisture, and photosynthetically active radiation (PAR) during the hottest three consecutive days in August 2016. Results showed that each variable responded differently to the edge effects. This urban forest edge had an effect on temporal changes at a diurnal scale in all microclimate variables, except soil moisture. In addition, all variables except relative humidity were significantly influenced by the edge effect up to 15 m inward from the forest boundary. The relative humidity fluctuated the most and showed the deepest extent of the edge effect. Moreover, the edge widths calculated from the relative humidity and air temperature both peaked in the late afternoon (16:00 h). Our findings provide a reference for forest managers in designing urban forest zones and will contribute to the conservation of fragmented forests in urban areas.
Red-edge position of habitable exoplanets around M-dwarfs.

Science.gov (United States)

Takizawa, Kenji; Minagawa, Jun; Tamura, Motohide; Kusakabe, Nobuhiko; Narita, Norio

2017-08-08

One of the possible signs of life on distant habitable exoplanets is the red-edge, which is a rise in the reflectivity of planets between visible and near-infrared (NIR) wavelengths. Previous studies suggested the possibility that the red-edge position for habitable exoplanets around M-dwarfs may be shifted to a longer wavelength than that for Earth. We investigated plausible red-edge position in terms of the light environment during the course of the evolution of phototrophs. We show that phototrophs on M-dwarf habitable exoplanets may use visible light when they first evolve in the ocean and when they first colonize the land. The adaptive evolution of oxygenic photosynthesis may eventually also use NIR radiation, by one of two photochemical reaction centers, with the other center continuing to use visible light. These "two-color" reaction centers can absorb more photons, but they will encounter difficulty in adapting to drastically changing light conditions at the boundary between land and water. NIR photosynthesis can be more productive on land, though its evolution would be preceded by the Earth-type vegetation. Thus, the red-edge position caused by photosynthetic organisms on habitable M-dwarf exoplanets could initially be similar to that on Earth and later move to a longer wavelength.

Stability of edge states and edge magnetism in graphene nanoribbons

OpenAIRE

Kunstmann, Jens; Özdoğan, Cem; Quandt, Alexander; Fehske, Holger

2010-01-01

We critically discuss the stability of edge states and edge magnetism in zigzag edge graphene nanoribbons (ZGNRs). We point out that magnetic edge states might not exist in real systems, and show that there are at least three very natural mechanisms - edge reconstruction, edge passivation, and edge closure - which dramatically reduce the effect of edge states in ZGNRs or even totally eliminate them. Even if systems with magnetic edge states could be made, the intrinsic magnetism would not be ...
The prosody of Swedish underived nouns: No lexical tones required

Directory of Open Access Journals (Sweden)

Bruce Morén-Duolljá

2013-02-01

Full Text Available This paper provides a detailed representational analysis of the morpho-prosodic system of underived nouns in a dialect of Swedish. It shows that the morphology, stress and tonal patterns are not as complex as they first appear once the data are looked at in sufficient detail. Further, it shows that the renowned Swedish "lexical pitch accent" is not the result of lexical tones/tonemes. Rather, Swedish is like all other languages and uses tones to mark the edges of prosodic constituents on the surface. "Accent 2" occurs when tones mark the edge of a structural uneven trochee (i.e. recursive foot and "accent 1" occurs elsewhere. This analysis is counter all other treatments of North Germanic tones and denies the almost unquestioned assumption that there is an underlying tone specification on roots and/or affixes in many North Germanic varieties. At the same time, it unifies the intuitions behind the three previous approaches found in the literature.
Edge states of a periodic chain with four-band energy spectrum

International Nuclear Information System (INIS)

Eliashvili, Merab; Kereselidze, Davit; Tsitsishvili, George; Tsitsishvili, Mikheil

2017-01-01

Tight-binding model on a finite chain is studied with four-fold alternated hopping parameters t_1_,_2_,_3_,_4. Imposing the open boundary conditions, the corresponding recursion is solved analytically with special attention paid to the occurrence of edge states. Corresponding results are strongly corroborated by numeric calculations. It is shown that in the system there exist four different edge phases if the number of sites is odd, and eight edges phases if the chain comprises even number of sites. Phases are labelled by σ_1 ≡ sgn(t_1t_3 − t_2t_4), σ_2 ≡ sgn(t_1t_4 − t_2t_3), and σ_3 ≡ sgn(t_1t_2 − t_3t_4). It is shown that σ_1_,_2_,_3 represent gauge invariant topological indices emerging in the corresponding infinite chains. (author)
Categorical perception of color: evidence from secondary category boundary

Directory of Open Access Journals (Sweden)

Al-rasheed AS

2015-11-01

Full Text Available Abdulrahman Saud Al-rasheed Department of Psychology, King Saud University, Riyadh, Kingdom of Saudi Arabia Abstract: Despite a plethora of behavioral research exploring the phenomenon of color categorical perception (CP known as "better discrimination between pair of colors stimuli from different categories and pair of colors stimuli from the same category even when the stimulus differences between the pairs of stimuli are equal", most of the evidence for the CP of color was derived from Roman or top-to-down script readers and very rarely from right-to-left script readers in primary category. To date, no studies of color CP have been conducted on right-to-left script readers in secondary category boundary to support this theory. Three experiments have been conducted: Experiments 1 and 2 established the Arabic blue–purple secondary category boundary, and Experiment 3 tested the CP of color in the blue–purple category boundary. Sixty participants (30 men and 30 women took part in this study. All spoke Arabic as their first language, and all were undergraduate or postgraduate students at King Saud University. Their ages ranged from 18–35 years with a mean age of 21.9 years (SD =5.2. The result indicated that for Experiments 1 and 2, it appeared that the Arabic blue–purple category boundary was approximately 10PB and it is in the same location as for English. For Experiment 3, reaction times in the between-categories condition were significantly faster than those in the within-category condition; this suggested that CP of color was shown in the Arabic's blue–purple secondary category boundary. Keywords: categorical perception, CP of color, categorization, blue–purple category boundary, secondary category boundary
Transport in the tokamak plasma edge

International Nuclear Information System (INIS)

Vold, E.L.

1989-01-01

Experimental observations characterize the edge plasma or boundary layer in magnetically confined plasmas as a region of great complexity. Evidence suggests the edge physics plays a key role in plasma confinement although the mechanism remains unresolved. This study focuses on issues in two areas: observed poloidal asymmetries in the Scrape Off Layer (SOL) edge plasma and the physical nature of the plasma-neutral recycling. A computational model solves the coupled two dimensional partial differential equations governing the plasma fluid density, parallel and radial velocities, electron and ion temperatures and neutral density under assumptions of toroidal symmetry, ambipolarity, anomalous diffusive radial flux, and neutral-ion thermal equilibrium. Drift flow and plasma potential are calculated as dependent quantities. Computational results are compared to experimental data for the CCT and TEXTOR:ALT-II tokamak limiter cases. Comparisons show drift flux is a major component of the poloidal flow in the SOL along the tangency/separatrix. Plasma-neutral recycling is characterized in several tokamak divertors, including the C-MOD device using magnetic flux surface coordinates. Recycling is characterized by time constant, τ rc , on the order of tens of milliseconds. Heat flux transients from the core into the edge on shorter time scales significantly increase the plasma temperatures at the target and may increase sputtering. Recycling conditions in divertors vary considerably depending on recycled flux to the core. The high density, low temperature solution requires that the neutral mean free path be small compared to the divertor target to x-point distance. The simulations and analysis support H-mode confinement and transition models based on the recycling divertor solution bifurcation
Theoretic base of Edge Local Mode triggering by vertical displacements

Energy Technology Data Exchange (ETDEWEB)

Wang, Z. T. [Southwestern Institute of Physics, Chengdu 610041 (China); College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China); He, Z. X.; Wang, Z. H. [Southwestern Institute of Physics, Chengdu 610041 (China); Wu, N.; Tang, C. J. [College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China)

2015-05-15

Vertical instability is studied with R-dependent displacement. For Solovev's configuration, the stability boundary of the vertical instability is calculated. The pressure gradient is a destabilizing factor which is contrary to Rebhan's result. Equilibrium parallel current density, j{sub //}, at plasma boundary is a drive of the vertical instability similar to Peeling-ballooning modes; however, the vertical instability cannot be stabilized by the magnetic shear which tends towards infinity near the separatrix. The induced current observed in the Edge Local Mode (ELM) triggering experiment by vertical modulation is derived. The theory provides some theoretic explanation for the mitigation of type-I ELMS on ASDEX Upgrade. The principle could be also used for ITER.
Relevance, Realization and stability of a cold layer at the plasma edge for fusion reactors

International Nuclear Information System (INIS)

1990-09-01

The workshop was dedicated to the realization and stability of a cold layer at the plasma edge for fusion reactors. The subjects of the communications presented were: impurity transport, and control, plasma boundary layers, power balance, radiation control and modifications, limiter discharges, tokamak density limit, Asdex divertor discharges, thermal stability of a radiating diverted plasma, plasma stability, auxiliary heating in Textor, detached plasma in Tore Supra, poloidal divertor tokamak, radiation cooling, neutral-particle transport, plasma scrape-off layer, edge turbulence
Analysis of dimensionality effect on shock wave boundary layer interaction in laminar hypersonic flows

International Nuclear Information System (INIS)

John, Bibin; Surendranath, Srikanth; Natarajan, Ganesh; Kulkarni, Vinayak

2016-01-01

Highlights: • Leading edge bluntness based separation control has been analysed numerically for 2D and axi-symmetric flows. • Differential growth of entropy layer in the streamwise direction in these cases leads to different interaction with respective boundary layers. • Separation control is found possible for planar flows beyond a critical radius called as equivalent radius. • No equivalent radius has been noticed in axi-symmertric flows in the present studies due to thin entropy layer and lack of favourable pressure gradient. - Abstract: Present investigations are centered on passive control of shock wave boundary layer interaction (SWBLI) for double cone and double wedge configurations with leading edge bluntness. This study seeks the differences in the flow physics of SWBLI in case of two dimensional (2D) and axisymmetric flow fields. In-house developed second order accurate finite-volume 2D axisymmetric compressible flow solver is employed for these studies. It is observed that the idea of leading edge bluntness offers reduction in separation bubble for 2D flow fields, whereas it leads to enhanced separation zone in case of axisymmetric flow fields. Relevant flow physics is well explored herein using wall pressure profile and relative thicknesses of boundary layer and entropy layer. Thicker entropy layer and stronger favorable pressure gradient are found responsible for the possibility of separation control in case of 2D flow fields. Thin entropy layer due to three dimensional relieving effect and its swallowing by the boundary layer are attributed for higher separation bubble size in case of cone with range of radii under consideration.
Introducing the Boundary Element Method with MATLAB

Science.gov (United States)

Ang, Keng-Cheng

2008-01-01

The boundary element method provides an excellent platform for learning and teaching a computational method for solving problems in physical and engineering science. However, it is often left out in many undergraduate courses as its implementation is deemed to be difficult. This is partly due to the perception that coding the method requires…
Effects of a sheared toroidal rotation on the stability boundary of the MHD modes in the tokamak edge pedestal

International Nuclear Information System (INIS)

Aiba, N.; Tokuda, S.; Oyama, N.; Ozeki, T.; Furukawa, M.

2009-01-01

Effects of a sheared toroidal rotation are investigated numerically on the stability of the MHD modes in the tokamak edge pedestal, which relate to the type-I edge-localized mode. A linear MHD stability code MINERVA is newly developed for solving the Frieman-Rotenberg equation that is the linear ideal MHD equation with flow. Numerical stability analyses with this code reveal that the sheared toroidal rotation destabilizes edge localized MHD modes for rotation frequencies which are experimentally achievable, though the ballooning mode stability changes little by rotation. This rotation effect on the edge MHD stability becomes stronger as the toroidal mode number of the unstable MHD mode increases when the stability analysis was performed for MHD modes with toroidal mode numbers smaller than 40. The toroidal mode number of the unstable MHD mode depends on the stabilization of the current-driven mode and the ballooning mode by increasing the safety factor. This dependence of the toroidal mode number of the unstable mode on the safety factor is considered to be the reason that the destabilization by toroidal rotation is stronger for smaller edge safety factors.
Critical gradients and plasma flows in the edge plasma of Alcator C-Moda)

Science.gov (United States)

Labombard, B.; Hughes, J. W.; Smick, N.; Graf, A.; Marr, K.; McDermott, R.; Reinke, M.; Greenwald, M.; Lipschultz, B.; Terry, J. L.; Whyte, D. G.; Zweben, S. J.; Alcator C-Mod Team

2008-05-01

Recent experiments have led to a fundamental shift in our view of edge transport physics; transport near the last-closed flux surface may be more appropriately described in terms of a critical gradient phenomenon rather than a diffusive and/or convective paradigm. Edge pressure gradients, normalized by the square of the poloidal magnetic field strength, appear invariant in plasmas with the same normalized collisionality, despite vastly different currents and magnetic fields—a behavior that connects with first-principles electromagnetic plasma turbulence simulations. Near-sonic scrape-off layer (SOL) flows impose a cocurrent rotation boundary condition on the confined plasma when B ×∇B points toward the active x-point, suggesting a link to the concomitant reduction in input power needed to attain high-confinement modes. Indeed, low-confinement mode plasmas are found to attain higher edge pressure gradients in this configuration, independent of the direction of B, evidence that SOL flows may affect transport and "critical gradient" values in the edge plasma.
Three-Dimensional Vibration Analysis of Rectangular Thick Plates on Pasternak Foundation with Arbitrary Boundary Conditions

Directory of Open Access Journals (Sweden)

Huimin Liu

2017-01-01

Full Text Available This paper presents the first known vibration characteristic of rectangular thick plates on Pasternak foundation with arbitrary boundary conditions on the basis of the three-dimensional elasticity theory. The arbitrary boundary conditions are obtained by laying out three types of linear springs on all edges. The modified Fourier series are chosen as the basis functions of the admissible function of the thick plates to eliminate all the relevant discontinuities of the displacements and their derivatives at the edges. The exact solution is obtained based on the Rayleigh–Ritz procedure by the energy functions of the thick plate. The excellent accuracy and reliability of current solutions are demonstrated by numerical examples and comparisons with the results available in the literature. In addition, the influence of the foundation coefficients as well as the boundary restraint parameters is also analyzed, which can serve as the benchmark data for the future research technique.
Voting based object boundary reconstruction

Science.gov (United States)

Tian, Qi; Zhang, Like; Ma, Jingsheng

2005-07-01

A voting-based object boundary reconstruction approach is proposed in this paper. Morphological technique was adopted in many applications for video object extraction to reconstruct the missing pixels. However, when the missing areas become large, the morphological processing cannot bring us good results. Recently, Tensor voting has attracted people"s attention, and it can be used for boundary estimation on curves or irregular trajectories. However, the complexity of saliency tensor creation limits its applications in real-time systems. An alternative approach based on tensor voting is introduced in this paper. Rather than creating saliency tensors, we use a "2-pass" method for orientation estimation. For the first pass, Sobel d*etector is applied on a coarse boundary image to get the gradient map. In the second pass, each pixel puts decreasing weights based on its gradient information, and the direction with maximum weights sum is selected as the correct orientation of the pixel. After the orientation map is obtained, pixels begin linking edges or intersections along their direction. The approach is applied to various video surveillance clips under different conditions, and the experimental results demonstrate significant improvement on the final extracted objects accuracy.
Categorical perception of color: evidence from secondary category boundary

Science.gov (United States)

Al-rasheed, Abdulrahman Saud

2015-01-01

Despite a plethora of behavioral research exploring the phenomenon of color categorical perception (CP) known as “better discrimination between pair of colors stimuli from different categories and pair of colors stimuli from the same category even when the stimulus differences between the pairs of stimuli are equal”, most of the evidence for the CP of color was derived from Roman or top-to-down script readers and very rarely from right-to-left script readers in primary category. To date, no studies of color CP have been conducted on right-to-left script readers in secondary category boundary to support this theory. Three experiments have been conducted: Experiments 1 and 2 established the Arabic blue–purple secondary category boundary, and Experiment 3 tested the CP of color in the blue–purple category boundary. Sixty participants (30 men and 30 women) took part in this study. All spoke Arabic as their first language, and all were undergraduate or postgraduate students at King Saud University. Their ages ranged from 18–35 years with a mean age of 21.9 years (SD =5.2). The result indicated that for Experiments 1 and 2, it appeared that the Arabic blue–purple category boundary was approximately 10PB and it is in the same location as for English. For Experiment 3, reaction times in the between-categories condition were significantly faster than those in the within-category condition; this suggested that CP of color was shown in the Arabic’s blue–purple secondary category boundary. PMID:26648764
Neutral particle transport modeling with a reflective source in the plasma edge

International Nuclear Information System (INIS)

Valenti, M.E.

1992-01-01

A reflective source term is incorporated into the Boltzmann neutral particle transport equation to account for boundary reflection. This reflective neutral model is integrated over a uniform axis and subsequently discretized. The discrete two-dimensional equations are solved iteratively with a computer code. The results of the reflective neutral model computer code are benchmarked with the neutral particle transport code ONEDANT. The benchmark process demonstrates the validity of the reflective neutral model. The reflective neutral model is coupled to the Braams plasma particle and energy transport code. The coupled system generates self-consistent plasma edge transport solutions. These solutions, which utilize the transport equation are similar to solutions which utilize simple plasma edge neutral models when high recycle divertors are modeled. In the high recycle mode, the high electron density at the divertor plate reduces the mean free path of plate neutrals. Hence, the similarity in results. It is concluded that simple neutral models are sufficient for the analysis of high recycle power reactor edge plasmas. Low recycle edge plasmas were not examined
Streamwise counter-rotating vortices generated by triangular leading edge pattern in flat plate boundary layer

KAUST Repository

Hasheminejad, S. M.; Mitsudharmadi, Hatsari; Winoto, S. H.; Lua, K. B.; Low, H. T.

2016-01-01

A series of flow visualizations were conducted to qualitatively study the development of streamwise counter-rotating vortices over a flat plate induced by triangular patterns at the leading edge of a flat plate. The experiments were carried out
Edge physics of the quantum spin Hall insulator from a quantum dot excited by optical absorption.

Science.gov (United States)

Vasseur, Romain; Moore, Joel E

2014-04-11

The gapless edge modes of the quantum spin Hall insulator form a helical liquid in which the direction of motion along the edge is determined by the spin orientation of the electrons. In order to probe the Luttinger liquid physics of these edge states and their interaction with a magnetic (Kondo) impurity, we consider a setup where the helical liquid is tunnel coupled to a semiconductor quantum dot that is excited by optical absorption, thereby inducing an effective quantum quench of the tunneling. At low energy, the absorption spectrum is dominated by a power-law singularity. The corresponding exponent is directly related to the interaction strength (Luttinger parameter) and can be computed exactly using boundary conformal field theory thanks to the unique nature of the quantum spin Hall edge.
An introductory study of the convergence of the direct boundary element method

DEFF Research Database (Denmark)

Juhl, Peter Møller

1997-01-01

of an axisymmetric boundary element formulation is studied using linear, quadratic or superparametric elements. It is demonstrated that the rate of convergence of these formulations is reduced for calculations involving bodies with edges (geometric singularities). Two methods for improving the rate of convergence...
On the stress investigation at the edges of the fixed elastic semi-strip

Directory of Open Access Journals (Sweden)

N. Vaysfeld

2016-10-01

Full Text Available The stress state of the elastic fixed semi-strip with the regarding of the singularities at its edge is investigated in the article. The initial boundary problem is reduced to a vector boundary problem in the transformation’s domain by the use of integral Fourier transformation. The one-dimensional vector boundary problem is solved exactly with the help of matrix differential calculations and Green’s matrix apparatus. The problem’s solving was focused at the solving of the singular integral equation (SIE with the two fixed singularities at the ends of the integration’s interval. The symbol of SIE was constructed and the generalized method of the SIE solving was applied. The stress’ distributions of the semi-strip are investigated
Left atrial isolation associated with mitral valve operations.

Science.gov (United States)

Graffigna, A; Pagani, F; Minzioni, G; Salerno, J; Viganò, M

1992-12-01

Surgical isolation of the left atrium was performed for the treatment of chronic atrial fibrillation secondary to valvular disease in 100 patients who underwent mitral valve operations. From May 1989 to September 1991, 62 patients underwent mitral valve operations (group I); 19, mitral valve operations and DeVega tricuspid annuloplasty (group II); 15, mitral and aortic operations (group III); and 4, mitral and aortic operations and DeVega tricuspid annuloplasty (group IV). Left atrial isolation was performed, prolonging the usual left paraseptal atriotomy toward the left fibrous trigone anteriorly and the posteromedial commissure posteriorly. The incision was conducted a few millimeters apart from the mitral valve annulus, and cryolesions were placed at the edges to ensure complete electrophysiological isolation of the left atrium. Operative mortality accounted for 3 patients (3%). In 79 patients (81.4%) sinus rhythm recovered and persisted until discharge from the hospital. No differences were found between the groups (group I, 80.7%; group II, 68.5%; group III, 86.7%; group IV, 75%; p = not significant). Three late deaths (3.1%) were registered. Long-term results show persistence of sinus rhythm in 71% of group I, 61.2% of group II, 85.8% of group III, and 100% of group IV. The unique risk factor for late recurrence of atrial fibrillation was found to be preoperative atrial fibrillation longer than 6 months. Due to the satisfactory success rate in recovering sinus rhythm, we suggest performing left atrial isolation in patients with chronic atrial fibrillation undergoing valvular operations.

Edge detection of magnetic anomalies using analytic signal of tilt angle (ASTA)

Science.gov (United States)

Alamdar, K.; Ansari, A. H.; Ghorbani, A.

2009-04-01

Magnetic is a commonly used geophysical technique to identify and image potential subsurface targets. Interpretation of magnetic anomalies is a complex process due to the superposition of multiple magnetic sources, presence of geologic and cultural noise and acquisition and positioning error. Both the vertical and horizontal derivatives of potential field data are useful; horizontal derivative, enhance edges whereas vertical derivative narrow the width of anomaly and so locate source bodies more accurately. We can combine vertical and horizontal derivative of magnetic field to achieve analytic signal which is independent to body magnetization direction and maximum value of this lies over edges of body directly. Tilt angle filter is phased-base filter and is defined as angle between vertical derivative and total horizontal derivative. Tilt angle value differ from +90 degree to -90 degree and its zero value lies over body edge. One of disadvantage of this filter is when encountering with deep sources the detected edge is blurred. For overcome this problem many authors introduced new filters such as total horizontal derivative of tilt angle or vertical derivative of tilt angle which Because of using high-order derivative in these filters results may be too noisy. If we combine analytic signal and tilt angle, a new filter termed (ASTA) is produced which its maximum value lies directly over body edge and is easer than tilt angle to delineate body edge and no complicity of tilt angle. In this work new filter has been demonstrated on magnetic data from an area in Sar- Cheshme region in Iran. This area is located in 55 degree longitude and 32 degree latitude and is a copper potential region. The main formation in this area is Andesith and Trachyandezite. Magnetic surveying was employed to separate the boundaries of Andezite and Trachyandezite from adjacent area. In this regard a variety of filters such as analytic signal, tilt angle and ASTA filter have been applied which
Spatially resolved mapping of electrical conductivity across individual domain (grain) boundaries in graphene.

Science.gov (United States)

Clark, Kendal W; Zhang, X-G; Vlassiouk, Ivan V; He, Guowei; Feenstra, Randall M; Li, An-Ping

2013-09-24

All large-scale graphene films contain extended topological defects dividing graphene into domains or grains. Here, we spatially map electronic transport near specific domain and grain boundaries in both epitaxial graphene grown on SiC and CVD graphene on Cu subsequently transferred to a SiO2 substrate, with one-to-one correspondence to boundary structures. Boundaries coinciding with the substrate step on SiC exhibit a significant potential barrier for electron transport of epitaxial graphene due to the reduced charge transfer from the substrate near the step edge. Moreover, monolayer-bilayer boundaries exhibit a high resistance that can change depending on the height of substrate step coinciding at the boundary. In CVD graphene, the resistance of a grain boundary changes with the width of the disordered transition region between adjacent grains. A quantitative modeling of boundary resistance reveals the increased electron Fermi wave vector within the boundary region, possibly due to boundary induced charge density variation. Understanding how resistance change with domain (grain) boundary structure in graphene is a crucial first step for controlled engineering of defects in large-scale graphene films.
A Third-Order p-Laplacian Boundary Value Problem Solved by an SL(3,ℝ Lie-Group Shooting Method

Directory of Open Access Journals (Sweden)

Chein-Shan Liu

2013-01-01

Full Text Available The boundary layer problem for power-law fluid can be recast to a third-order p-Laplacian boundary value problem (BVP. In this paper, we transform the third-order p-Laplacian into a new system which exhibits a Lie-symmetry SL(3,ℝ. Then, the closure property of the Lie-group is used to derive a linear transformation between the boundary values at two ends of a spatial interval. Hence, we can iteratively solve the missing left boundary conditions, which are determined by matching the right boundary conditions through a finer tuning of r∈[0,1]. The present SL(3,ℝ Lie-group shooting method is easily implemented and is efficient to tackle the multiple solutions of the third-order p-Laplacian. When the missing left boundary values can be determined accurately, we can apply the fourth-order Runge-Kutta (RK4 method to obtain a quite accurate numerical solution of the p-Laplacian.
Spatial characterization of the edge barrier in wide superconducting films

Science.gov (United States)

Sivakov, A. G.; Turutanov, O. G.; Kolinko, A. E.; Pokhila, A. S.

2018-03-01

The current-induced destruction of superconductivity is discussed in wide superconducting thin films, whose width is greater than the magnetic field penetration depth, in weak magnetic fields. Particular attention is paid to the role of the boundary potential barrier (the Bin-Livingston barrier) in critical state formation and detection of the edge responsible for this critical state with different mutual orientations of external perpendicular magnetic field and transport current. Critical and resistive states of the film were visualized using the space-resolving low-temperature laser scanning microscopy (LTLSM) method, which enables detection of critical current-determining areas on the film edges. Based on these observations, a simple technique was developed for investigation of the critical state separately at each film edge, and for the estimation of residual magnetic fields in cryostats. The proposed method only requires recording of the current-voltage characteristics of the film in a weak magnetic field, thus circumventing the need for complex LTLSM techniques. Information thus obtained is particularly important for interpretation of studies of superconducting film single-photon light emission detectors.
Statistical Analysis of SSMIS Sea Ice Concentration Threshold at the Arctic Sea Ice Edge during Summer Based on MODIS and Ship-Based Observational Data.

Science.gov (United States)

Ji, Qing; Li, Fei; Pang, Xiaoping; Luo, Cong

2018-04-05

The threshold of sea ice concentration (SIC) is the basis for accurately calculating sea ice extent based on passive microwave (PM) remote sensing data. However, the PM SIC threshold at the sea ice edge used in previous studies and released sea ice products has not always been consistent. To explore the representable value of the PM SIC threshold corresponding on average to the position of the Arctic sea ice edge during summer in recent years, we extracted sea ice edge boundaries from the Moderate-resolution Imaging Spectroradiometer (MODIS) sea ice product (MOD29 with a spatial resolution of 1 km), MODIS images (250 m), and sea ice ship-based observation points (1 km) during the fifth (CHINARE-2012) and sixth (CHINARE-2014) Chinese National Arctic Research Expeditions, and made an overlay and comparison analysis with PM SIC derived from Special Sensor Microwave Imager Sounder (SSMIS, with a spatial resolution of 25 km) in the summer of 2012 and 2014. Results showed that the average SSMIS SIC threshold at the Arctic sea ice edge based on ice-water boundary lines extracted from MOD29 was 33%, which was higher than that of the commonly used 15% discriminant threshold. The average SIC threshold at sea ice edge based on ice-water boundary lines extracted by visual interpretation from four scenes of the MODIS image was 35% when compared to the average value of 36% from the MOD29 extracted ice edge pixels for the same days. The average SIC of 31% at the sea ice edge points extracted from ship-based observations also confirmed that choosing around 30% as the SIC threshold during summer is recommended for sea ice extent calculations based on SSMIS PM data. These results can provide a reference for further studying the variation of sea ice under the rapidly changing Arctic.
The interpretation of prosodic variability in the context of accompanying sociophonetic cues

Directory of Open Access Journals (Sweden)

Paul Warren

2017-05-01

Full Text Available Production data have shown that one of the features distinguishing uptalk rises from question rises in New Zealand English (NZE is the alignment point of the rise start, which is earlier in question utterances realized by younger speakers. Previous research has indicated that listeners are sensitive to this distinction in making a forced-choice decision as to whether an utterance is a statement or a question. NZE is also characterized by an ongoing merger of the NEAR and SQUARE diphthongs, with younger speakers more likely to realize the vowel in a word such as 'care 'with a closer starting point (as in [iɘ], overlapping with their realization of the NEAR vowel, whereas older speakers would have more open starting point (as in [eɘ]. The current study uses the mouse-tracking paradigm to provide evidence that the realization of SQUARE with an innovative vs. a conservative variant in a word early in an utterance affects NZE listeners’ sensitivity firstly to a rise as a potential signal of an uptalked statement and secondly to the early alignment of the rise as a signal of a question. This finding indicates that the interpretation of prosodic variability can depend on speaker characteristics imputed from other sociophonetic cues.
Boundary discontinuous Fourier analysis of thick beams with clamped and simply supported edges via CUF

Directory of Open Access Journals (Sweden)

F.G. CANALES

2017-10-01

Full Text Available This paper presents an analytical solution for static analysis of thick rectangular beams with different boundary conditions. Carrera’s Unified Formulation (CUF is used in order to consider shear deformation theories of arbitrary order. The novelty of the present work is that a boundary discontinuous Fourier approach is used to consider clamped boundary conditions in the analytical solution, unlike Navier-type solutions which are restricted to simply supported beams. Governing equations are obtained by employing the principle of virtual work. The numerical accuracy of results is ascertained by studying the convergence of the solution and comparing the results to those of a 3D finite element solution. Beams subjected to bending due to a uniform pressure load and subjected to torsion due to opposite linear forces are considered. Overall, accurate results close to those of 3D finite element solutions are obtained, which can be used to validate finite element results or other approximate methods.
Simulations of edge and scrape off layer turbulence in mega ampere spherical tokamak plasmas

DEFF Research Database (Denmark)

Militello, F; Fundamenski, W; Naulin, Volker

2012-01-01

The L-mode interchange turbulence in the edge and scrape-off-layer (SOL) of the tight aspect ratio tokamak MAST is investigated numerically. The dynamics of the boundary plasma are studied using the 2D drift-fluid code ESEL, which has previously shown good agreement with large aspect ratio machin...
Electron temperature gradient driven instability in the tokamak boundary plasma

International Nuclear Information System (INIS)

Xu, X.Q.; Rosenbluth, M.N.; Diamond, P.H.

1992-01-01

A general method is developed for calculating boundary plasma fluctuations across a magnetic separatrix in a tokamak with a divertor or a limiter. The slab model, which assumes a periodic plasma in the edge reaching the divertor or limiter plate in the scrape-off layer(SOL), should provide a good estimate, if the radial extent of the fluctuation quantities across the separatrix to the edge is small compared to that given by finite particle banana orbit. The Laplace transform is used for solving the initial value problem. The electron temperature gradient(ETG) driven instability is found to grow like t -1/2 e γmt
Delusional misidentifications and duplications: right brain lesions, left brain delusions.

Science.gov (United States)

Devinsky, Orrin

2009-01-06

When the delusional misidentification syndromes reduplicative paramnesia and Capgras syndromes result from neurologic disease, lesions are usually bifrontal and/or right hemispheric. The related disorders of confabulation and anosognosis share overlapping mechanisms and anatomic pathology. A dual mechanism is postulated for the delusional misidentification syndromes: negative effects from right hemisphere and frontal lobe dysfunction as well as positive effects from release (i.e., overactivity) of preserved left hemisphere areas. Negative effects of right hemisphere injury impair self-monitoring, ego boundaries, and attaching emotional valence and familiarity to stimuli. The unchecked left hemisphere unleashes a creative narrator from the monitoring of self, memory, and reality by the frontal and right hemisphere areas, leading to excessive and false explanations. Further, the left hemisphere's cognitive style of categorization, often into dual categories, leads it to invent a duplicate or impostor to resolve conflicting information. Delusions result from right hemisphere lesions. But it is the left hemisphere that is deluded.
Structure of the low-latitude boundary layer

International Nuclear Information System (INIS)

Sckopke, N.; Paschmann, G.; Haerendel, G.; Sonnerup, B.U.O.; Bame, S.J.; Forbes, T.G.; Hones, E.W. Jr.; Russell, C.T.

1981-01-01

Observations at high temporal resolution of the frontside magnetopause and plasma boundary layer, made with the Los Alamos Scientific Laboratory/Max-Planck-Institut, Institut fuer Extraterrestrische Physik, fast plasma analyzer on board the Isee 1 and 2 spacecraft, have revealed a complex quasi-periodic structure of some of the observed boundary layers: cool tailward streaming boundary layer plasma is seen intermittently, with intervening periods of hot tenuous plasma which has properties similar to the magnetospheric population. While individual encounters with the boundary layer plasma last only a few minutes, the total observation time may extend over 1 hour or more. One such crossing, at 0800 hours local time and 40 0 northern GSM latitude, is examined in detail, including a quantitative comparison of the boundary layer entry and exit times of the two spacecraft. The data are found to be compatible with a boundary layer that is always attached to the magnetopause but where the layer thickness has a large-scale spatial modulation pattern which travels tailward past the spacecraft. Included are periods when the thickness is essentially zero and others when it is of the order of 1 R/sub E/. The duration of these periods is highly variable but is typically in the range of 2--5 min, corresponding to a distance along the magnetopause of the order of 3--8 R/sub E/. The observed boundary layer features include a steep density gradient at the magnetopause, with an approximately constant boundary layer plasma density amounting to about 25% of the magnetosheath density, and a second abrupt density decrease at the inner edge of the layer. It also appears that the purely magnetospheric plasma is ocassionally separated from the boundary layer by a halo region in which the plasma density is somewhat higher, and the temperature somewhat lower, than in the magnetosphere. A tentative model is proposed
Vibration Analysis of Annular Sector Plates under Different Boundary Conditions

Directory of Open Access Journals (Sweden)

Dongyan Shi

2014-01-01

Full Text Available An analytical framework is developed for the vibration analysis of annular sector plates with general elastic restraints along each edge of plates. Regardless of boundary conditions, the displacement solution is invariably expressed as a new form of trigonometric expansion with accelerated convergence. The expansion coefficients are treated as the generalized coordinates and determined using the Rayleigh-Ritz technique. This work allows a capability of modeling annular sector plates under a variety of boundary conditions and changing the boundary conditions as easily as modifying the material properties or dimensions of the plates. Of equal importance, the proposed approach is universally applicable to annular sector plates of any inclusion angles up to 2π. The reliability and accuracy of the current method are adequately validated through numerical examples.
DIII-D Edge Plasma, Disruptions, and Radiative Processes. Final Report

Energy Technology Data Exchange (ETDEWEB)

Boedo, J. A.; Luckhardt, S.C.; Moyer, R. A.

2001-01-01

The scientific goal of the UCSD-DIII-D Collaboration during this period was to understand the coupling of the core plasma to the plasma-facing components through the plasma boundary (edge and scrape-off layer). To achieve this goal, UCSD scientists studied the transport of particles, momentum, energy, and radiation from the plasma core to the plasma-facing components under normal (e.g., L-mode, H-mode, and ELMs), and off-normal (e.g., disruptions) operating conditions.
DIII-D Edge Plasma, Disruptions, and Radiative Processes. Final Report

International Nuclear Information System (INIS)

Boedo, J. A.; Luckhardt, S.C.; Moyer, R. A.

2001-01-01

The scientific goal of the UCSD-DIII-D Collaboration during this period was to understand the coupling of the core plasma to the plasma-facing components through the plasma boundary (edge and scrape-off layer). To achieve this goal, UCSD scientists studied the transport of particles, momentum, energy, and radiation from the plasma core to the plasma-facing components under normal (e.g., L-mode, H-mode, and ELMs), and off-normal (e.g., disruptions) operating conditions
Defects and boundary layers in non-Euclidean plates

International Nuclear Information System (INIS)

Gemmer, J A; Venkataramani, S C

2012-01-01

We investigate the behaviour of non-Euclidean plates with constant negative Gaussian curvature using the Föppl–von Kármán reduced theory of elasticity. Motivated by recent experimental results, we focus on annuli with a periodic profile. We prove rigorous upper and lower bounds for the elastic energy that scales like the thickness squared. In particular we show that are only two types of global minimizers—deformations that remain flat and saddle shaped deformations with isolated regions of stretching near the edge of the annulus. We also show that there exist local minimizers with a periodic profile that have additional boundary layers near their lines of inflection. These additional boundary layers are a new phenomenon in thin elastic sheets and are necessary to regularize jump discontinuities in the azimuthal curvature across lines of inflection. We rigorously derive scaling laws for the width of these boundary layers as a function of the thickness of the sheet. (paper)
Model for adhesion clutch explains biphasic relationship between actin flow and traction at the cell leading edge

Science.gov (United States)

Craig, Erin M.; Stricker, Jonathan; Gardel, Margaret L.; Mogilner, Alex

2015-01-01

Cell motility relies on the continuous reorganization of a dynamic actin-myosin-adhesion network at the leading edge of the cell, in order to generate protrusion at the leading edge and traction between the cell and its external environment. We analyze experimentally measured spatial distributions of actin flow, traction force, myosin density, and adhesion density in control and pharmacologically perturbed epithelial cells in order to develop a mechanical model of the actin-adhesion-myosin self-organization at the leading edge. A model in which the F-actin network is treated as a viscous gel, and adhesion clutch engagement is strengthened by myosin but weakened by actin flow, can explain the measured molecular distributions and correctly predict the spatial distributions of the actin flow and traction stress. We test the model by comparing its predictions with measurements of the actin flow and traction stress in cells with fast and slow actin polymerization rates. The model predicts how the location of the lamellipodium-lamellum boundary depends on the actin viscosity and adhesion strength. The model further predicts that the location of the lamellipodium-lamellum boundary is not very sensitive to the level of myosin contraction. PMID:25969948
Strong Bulk-Edge Coupling in the Compressible Half-Filled Quantum Hall State

International Nuclear Information System (INIS)

Milovanovic, M.V.; Shimshoni, E.

1999-01-01

We studied analytically static correlators in the compressible half-filled quantum Hall state, which characterize the nature of charged excitations in the bulk and on the edge of the system. We employ a modified version of the plasma analogy - namely, a mapping to a classical two-dimensional system of interacting particles - similarly to what has been done in studies of the incompressible (Laughlin) states. However, the 'fake plasma' corresponding to the half-filled state is found to have anomalously weak screening properties. As a consequence, the correlations along the edge do not decay algebraically as in the incompressible case, thus indicating the breakdown of Wen's edge theory. On the other hand, the bulk correlator (which parallels the Girvin-MacDonald algebraic off-diagonal long range order) decays algebraically in a similar way as in the incompressible states, signifying the presence of some kind of bosonic order even in the compressible state. The above results suggest that due to the strong coupling between charged modes on the edge and the neutral Fermions (dipoles) in the bulk, the (attractive) correlation hole is not well defined on the edge. Hence, the system there can be modeled as a free Fermi gas of electrons (with an appropriate boundary condition). A possible experimental indication of a strong bulk-edge coupling at half-filling has been indeed observed in non-local resistance measurements [1]. We also suggest, that while our results contradict the validity of an effective one-dimensional description of the edge excitations on the static level, the dynamics may decouple the edge and bulk so as to recover the Laughlin-like behavior apparent in the experiment of Grayson et al
On the boundary behavior of left-invariant Hitchin and hypo flows

DEFF Research Database (Denmark)

Belgun, Florin; Cortés, Vicente; Freibert, Marco

2015-01-01

We investigate left-invariant Hitchin and hypo flows on 5-, 6- and 7-dimensional Lie groups. They provide Riemannian cohomogeneity-one manifolds of one dimension higher with holonomy contained in SU(3), G2 and Spin(7), respectively, which are in general geodesically incomplete. Generalizing results...... of Conti, we prove that for large classes of solvable Lie groups G these manifolds cannot be completed: a complete Riemannian manifold with parallel SU(3)-, G2- or Spin(7)-structure which is of cohomogeneity one with respect to G is flat, and has no singular orbits. We furthermore classify, on the non...
A hybrid scheme for absorbing edge reflections in numerical modeling of wave propagation

KAUST Repository

Liu, Yang; Sen, Mrinal K.

2010-01-01

We propose an efficient scheme to absorb reflections from the model boundaries in numerical solutions of wave equations. This scheme divides the computational domain into boundary, transition, and inner areas. The wavefields within the inner and boundary areas are computed by the wave equation and the one-way wave equation, respectively. The wavefields within the transition area are determined by a weighted combination of the wavefields computed by the wave equation and the one-way wave equation to obtain a smooth variation from the inner area to the boundary via the transition zone. The results from our finite-difference numerical modeling tests of the 2D acoustic wave equation show that the absorption enforced by this scheme gradually increases with increasing width of the transition area. We obtain equally good performance using pseudospectral and finite-element modeling with the same scheme. Our numerical experiments demonstrate that use of 10 grid points for absorbing edge reflections attains nearly perfect absorption. © 2010 Society of Exploration Geophysicists.
A hybrid scheme for absorbing edge reflections in numerical modeling of wave propagation

KAUST Repository

Liu, Yang

2010-03-01

We propose an efficient scheme to absorb reflections from the model boundaries in numerical solutions of wave equations. This scheme divides the computational domain into boundary, transition, and inner areas. The wavefields within the inner and boundary areas are computed by the wave equation and the one-way wave equation, respectively. The wavefields within the transition area are determined by a weighted combination of the wavefields computed by the wave equation and the one-way wave equation to obtain a smooth variation from the inner area to the boundary via the transition zone. The results from our finite-difference numerical modeling tests of the 2D acoustic wave equation show that the absorption enforced by this scheme gradually increases with increasing width of the transition area. We obtain equally good performance using pseudospectral and finite-element modeling with the same scheme. Our numerical experiments demonstrate that use of 10 grid points for absorbing edge reflections attains nearly perfect absorption. © 2010 Society of Exploration Geophysicists.

Migration energy barriers of symmetric tilt grain boundaries in body-centered cubic metal Fe

International Nuclear Information System (INIS)

Wu, Minghui; Gu, Jianfeng; Jin, Zhaohui

2015-01-01

Graphical abstract: DFT calculated migration energy barrier (left) for symmetric grain boundary in metals is an essential physical property to measure the trend of grain boundary migration, in particular, in terms of the classical homogeneous nucleation model of GB dislocation/disconnection loops (right). - Migration energy barriers of two symmetric tilt grain boundaries in body-centered cubic metal Fe are obtained via first-principles calculations in combination with the nudged elastic band methods. Although the two grain boundaries show similar grain boundary energies, the migration energy barriers are different. Based on a homogeneous nucleation theory of grain-boundary dislocation loops, the calculated energy barrier provides a measure of intrinsic grain-boundary mobility and helps to evaluate effects due to vacancy and interstitial atoms such as carbon
At the edge of the Earth's magnetosphere: a survey by AMPTE-UKS

International Nuclear Information System (INIS)

Bryant, D.A.; Riggs, S.

1989-01-01

A survey is made, by using measurements from the Active Magnetospheric Particle Tracer Explorers - United Kingdom Satellite, of the interaction between plasmas of solar and terrestrial origin at the outer edge of the Earth's magnetosphere. The position of the boundary and its rate of movement are related statistically to solar-wind dynamic pressure and its variations. The first results are presented of a new type of analysis which aims to clarify the nature of the boundary layer that develops between the two plasmas by reordering, on the basis of a consistent relation between electron density and temperature, the normally erratic progress made by a spacecraft across the constantly moving region. Distinctive patterns found consistently for the electron and ion transitions suggest that diffusion, viscosity and loss to the atmosphere govern the boundary layer. Various possibilities are discussed for the topology of the region. Electron acceleration within the boundary layer is identified; its cause and relevance to dayside auroral precipitation are discussed. There is an indication that the transition in the magnetic field, across the magnetopause current layer, lies within, rather than immediately outside, the boundary layer. (author)
Simulation of the effects of grain boundary fission gas during thermal transients

International Nuclear Information System (INIS)

Fenske, G.R.; Emerson, J.E.; Beiersdorf, B.A.

1984-11-01

This report presents the results of an initial set of out-of-cell transient heating experiments performed on unirradiated UO 2 pellets fabricated to simulate the effect of grain boundary fission gas on fuel swelling and cladding failure. The fabrication involved trapping high-pressure argon on internal pores by sintering annular UO 2 pellets in a hot isostatic press (HIP). The pellet stack was subjected to two separate transients (DGF83-03A and -03B). Figures show photomicrographs of HIPped and non-HIPped UO 2 , respectively, and the adjacent cladding after DGF83-03B. Fuel melting occurred at the center of both the HIPped and non-HIPped pellets; however, a dark ring is present near the center in the HIPped fuel but not in the non-HIPped fuel. This dark band is a high-porosity region due to increased grain boundary/edge swelling in that pellet. In contrast, grain boundary/edge swelling did not occur in the non-HIPped pellets. Thus, the presence of the high-pressure argon trapped on internal pores during sintering in the HIP altered the microstructural behavior. Results of these preliminary tests indicate that the microstructural behavior of HIPped fuel during thermal transients is different from the behavior of conventionally fabricated fuel
Novel method for edge detection of retinal vessels based on the model of the retinal vascular network and mathematical morphology

Science.gov (United States)

Xu, Lei; Zheng, Xiaoxiang; Zhang, Hengyi; Yu, Yajun

1998-09-01

Accurate edge detection of retinal vessels is a prerequisite for quantitative analysis of subtle morphological changes of retinal vessels under different pathological conditions. A novel method for edge detection of retinal vessels is presented in this paper. Methods: (1) Wavelet-based image preprocessing. (2) The signed edge detection algorithm and mathematical morphological operation are applied to get the approximate regions that contain retinal vessels. (3) By convolving the preprocessed image with a LoG operator only on the detected approximate regions of retinal vessels, followed by edges refining, clear edge maps of the retinal vessels are fast obtained. Results: A detailed performance evaluation together with the existing techniques is given to demonstrate the strong features of our method. Conclusions: True edge locations of retinal vessels can be fast detected with continuous structures of retinal vessels, less non- vessel segments left and insensitivity to noise. The method is also suitable for other application fields such as road edge detection.
Functional lateralization of speech processing in adults and children who stutter

Directory of Open Access Journals (Sweden)

Yutaka eSato

2011-04-01

Full Text Available Developmental stuttering is a speech disorder in fluency characterized by repetitions, prolongations and silent blocks, especially in the initial parts of utterances. Although their symptoms are motor related, people who stutter show abnormal patterns of cerebral hemispheric dominance in both anterior and posterior language areas. It is unknown whether the abnormal functional lateralization in the posterior language area starts during childhood or emerges as a consequence of many years of stuttering. In order to address this issue, we measured the lateralization of hemodynamic responses in the auditory cortex during auditory speech processing in adults and children who stutter, including preschoolers, with near-infrared spectroscopy (NIRS. We used the analysis-resynthesis technique to prepare two types of stimuli: (i a phonemic contrast embedded in Japanese spoken words (/itta/ vs. /itte/ and (ii a prosodic contrast (/itta/ vs. /itta?/. In the baseline blocks, only /itta/ tokens were presented. In phonemic contrast blocks, /itta/ and /itte/ tokens were presented pseudo-randomly, and /itta/ and /itta?/ tokens in prosodic contrast blocks. In adults and children who do not stutter, there was a clear left-hemispheric advantage for the phonemic contrast compared to the prosodic contrast. Adults and children who stutter, however, showed no significant difference between the two stimulus conditions. A subject-by-subject analysis revealed that not a single subject who stutters showed a left advantage in the phonemic contrast over the prosodic contrast condition. These results indicate that the functional lateralization for auditory speech processing is in disarray among those who stutter, even at preschool age. These results shed light on the neural pathophysiology of developmental stuttering.
Hypersonic Engine Leading Edge Experiments in a High Heat Flux, Supersonic Flow Environment

Science.gov (United States)

Gladden, Herbert J.; Melis, Matthew E.

1994-01-01

A major concern in advancing the state-of-the-art technologies for hypersonic vehicles is the development of an aeropropulsion system capable of withstanding the sustained high thermal loads expected during hypersonic flight. Three aerothermal load related concerns are the boundary layer transition from laminar to turbulent flow, articulating panel seals in high temperature environments, and strut (or cowl) leading edges with shock-on-shock interactions. A multidisciplinary approach is required to address these technical concerns. A hydrogen/oxygen rocket engine heat source has been developed at the NASA Lewis Research Center as one element in a series of facilities at national laboratories designed to experimentally evaluate the heat transfer and structural response of the strut (or cowl) leading edge. A recent experimental program conducted in this facility is discussed and related to cooling technology capability. The specific objective of the experiment discussed is to evaluate the erosion and oxidation characteristics of a coating on a cowl leading edge (or strut leading edge) in a supersonic, high heat flux environment. Heat transfer analyses of a similar leading edge concept cooled with gaseous hydrogen is included to demonstrate the complexity of the problem resulting from plastic deformation of the structures. Macro-photographic data from a coated leading edge model show progressive degradation over several thermal cycles at aerothermal conditions representative of high Mach number flight.
How disturbance, competition and dispersal interact to prevent tree range boundaries from keeping pace with climate change

Science.gov (United States)

Liang, Y.; Duveneck, M.; Gustafson, E. J.; Serra-Diaz, J. M.; Thompson, J. R.

2017-12-01

Climate change is expected to cause geographic shifts in tree species' ranges, but such shifts may not keep pace with climate changes because seed dispersal distances are often limited and competition-induced changes in community composition can be relatively slow. Disturbances may speed changes in community composition, but the interactions among climate change, disturbance and competitive interactions to produce range shifts are poorly understood. We used a physiologically-based mechanistic landscape model to study these interactions in the northeastern United States. We designed a series of disturbance scenarios to represent varied disturbance regimes in terms of both disturbance extent and intensity. We simulated forest succession by incorporating climate change under a high emissions future, disturbances, seed dispersal, and competition using the landscape model parameterized with forest inventory data. Tree species range boundary shifts in the next century were quantified as the change in the location of the 5th (the trailing edge) and 95th (the leading edge) percentiles of the spatial distribution of simulated species. Simulated tree species range boundary shifts in New England over the next century were far below (usually Disturbances may expedite species` recruitment into new sites, but they had little effect on the velocity of simulated range boundary shifts. Range shifts at the trailing edge tended to be associated with photosynthetic capacity, competitive ability for light and seed dispersal ability, whereas shifts at the leading edge were associated only with photosynthetic capacity and competition for light. This study underscores the importance of understanding the role of interspecific competition and disturbance when studying tree range shifts.
Validations and improvements of airfoil trailing-edge noise prediction models using detailed experimental data

DEFF Research Database (Denmark)

Kamruzzaman, M.; Lutz, Th.; Würz, W.

2012-01-01

This paper describes an extensive assessment and a step by step validation of different turbulent boundary-layer trailing-edge noise prediction schemes developed within the European Union funded wind energy project UpWind. To validate prediction models, measurements of turbulent boundary-layer pr...... with measurements in the frequency region higher than 1 kHz, whereas they over-predict the sound pressure level in the low-frequency region. Copyright © 2011 John Wiley & Sons, Ltd.......-layer properties such as two-point turbulent velocity correlations, the spectra of the associated wall pressure fluctuations and the emitted trailing-edge far-field noise were performed in the laminar wind tunnel of the Institute of Aerodynamics and Gas Dynamics, University of Stuttgart. The measurements were...... carried out for a NACA 643-418 airfoil, at Re = 2.5 ×106, angle of attack of −6° to 6°. Numerical results of different prediction schemes are extensively validated and discussed elaborately. The investigations on the TNO-Blake noise prediction model show that the numerical wall pressure fluctuation...
Flow Visualization with Quantified Spatial and Temporal Errors Using Edge Maps

KAUST Repository

Bhatia, H.; Jadhav, S.; Bremer, P.; Guoning Chen,; Levine, J. A.; Nonato, L. G.; Pascucci, V.

2012-01-01

Robust analysis of vector fields has been established as an important tool for deriving insights from the complex systems these fields model. Traditional analysis and visualization techniques rely primarily on computing streamlines through numerical integration. The inherent numerical errors of such approaches are usually ignored, leading to inconsistencies that cause unreliable visualizations and can ultimately prevent in-depth analysis. We propose a new representation for vector fields on surfaces that replaces numerical integration through triangles with maps from the triangle boundaries to themselves. This representation, called edge maps, permits a concise description of flow behaviors and is equivalent to computing all possible streamlines at a user defined error threshold. Independent of this error streamlines computed using edge maps are guaranteed to be consistent up to floating point precision, enabling the stable extraction of features such as the topological skeleton. Furthermore, our representation explicitly stores spatial and temporal errors which we use to produce more informative visualizations. This work describes the construction of edge maps, the error quantification, and a refinement procedure to adhere to a user defined error bound. Finally, we introduce new visualizations using the additional information provided by edge maps to indicate the uncertainty involved in computing streamlines and topological structures. © 2012 IEEE.
Flow Visualization with Quantified Spatial and Temporal Errors Using Edge Maps

KAUST Repository

Bhatia, H.

2012-09-01

Robust analysis of vector fields has been established as an important tool for deriving insights from the complex systems these fields model. Traditional analysis and visualization techniques rely primarily on computing streamlines through numerical integration. The inherent numerical errors of such approaches are usually ignored, leading to inconsistencies that cause unreliable visualizations and can ultimately prevent in-depth analysis. We propose a new representation for vector fields on surfaces that replaces numerical integration through triangles with maps from the triangle boundaries to themselves. This representation, called edge maps, permits a concise description of flow behaviors and is equivalent to computing all possible streamlines at a user defined error threshold. Independent of this error streamlines computed using edge maps are guaranteed to be consistent up to floating point precision, enabling the stable extraction of features such as the topological skeleton. Furthermore, our representation explicitly stores spatial and temporal errors which we use to produce more informative visualizations. This work describes the construction of edge maps, the error quantification, and a refinement procedure to adhere to a user defined error bound. Finally, we introduce new visualizations using the additional information provided by edge maps to indicate the uncertainty involved in computing streamlines and topological structures. © 2012 IEEE.
Catching the news: Processing strategies in listening to dialogs as measured by ERPs

Directory of Open Access Journals (Sweden)

Pannekamp Ann

2007-10-01

Full Text Available Abstract Background The online segmentation of spoken single sentences has repeatedly been associated with a particular event-related brain potential. The brain response could be attributed to the perception of major prosodic boundaries, and was termed Closure Positive Shift (CPS. However, verbal exchange between humans is mostly realized in the form of cooperative dialogs instead of loose strings of single sentences. The present study investigated whether listeners use prosodic cues for structuring larger contextually embedded utterances (i.e. dialogs like in single sentence processing. Methods ERPs were recorded from listeners (n = 22 when presented with question-answer dialogs in German. The prosody of the answer (target sentence either matched the context provided by a question or did not match the context question. Results CPS responses to the processing of the target sentences are elicited, first, when listeners encounter information comprising 'novelties', i.e. information not mentioned in the preceding question but facts corrected between context and target. Thereby it is irrelevant whether the actual prosody of the target sentence is in congruence with the informative status or not. Second, when listeners encounter target sentences which do not convey any novelties but only previously 'given' already known information, the structuring of the speech input is driven by prosody again. The CPS is then elicited when listeners perceive major prosodic boundaries similar as for the processing of context-free single sentences. Conclusion The study establishes a link between the on-line structuring of context-free (single sentences and context-embedded utterances (dialogs as measured by ERPs. Moreover, the impact of prosodic phrasing and accentuation on the perception of spoken utterances on and beyond sentence level is discussed.
Swelling and gas release of grain-boundary pores in uranium dioxide

International Nuclear Information System (INIS)

Schrire, D.I.

1983-12-01

The swelling and gas release of overpressured grain boundary pores is sintered unirradiated uranium dioxide were investigated under isothermal conditions. The pores became overpressured when the ambient pressure was reduced, and the excess pressure driving force caused growth and interconnection of the pores, leading to eventual gas release. Swelling was measured continuously by a linear variable differential transformer, and open and closed porosity fractions were determined after the tests by immersion density and quantitative microscopy measurements. The sinter porosity consisted of pores situated on grain faces, grain edges, and grain corners. Isolated pores maintained their equilibrium shape while growing, without any measurable change in dihedral angle. Interconnection occurred predominantly along grain edges, without any evidence of pore sharpening or crack propagation at low driving forces. Extensive open porosity occurred at a threshold density of about 85% TD. There was an almost linear dependence of the initial swelling rate on the driving force, with an activation energy of 200+- 8 kJ/mole, in good agreement with published values of the activation energy for grain boundary diffusion
Playing on the edge

DEFF Research Database (Denmark)

Cermak-Sassenrath, Daniel

2018-01-01

and specific ways. For instance, gambling for money, party and drinking games, professional play and show sports, art installations, violent and military propaganda computer games, pervasive/mobile gaming, live-action role playing, festivals, performances, and games such as Ghosting and Planking. It is argued......Everything gets more interesting, challenging, or intense the closer it gets to the edge, and so does play. How edgy can play become and still be play? Based on Huizinga’s notion of play, this chapter discusses how a wide range of playful activities pushes the boundaries of play in different...... that in concert with a number of characteristics that mark an activity as play, play is essentially a subjective perspective and individual decision of the player. Huizinga calls this attitude the play spirit, which informs a player’s actions and is in turn sustained by them. Edgy digital or mobile games do...
Determination of uranium in bench test by L_Ⅲ-absorption edge method

International Nuclear Information System (INIS)

Song You; Zheng Weiming; Liu Guijiao; Chen Chen

2014-01-01

By independent research L_Ⅲ--absorption edge densimeter, an analytical method for uranium sample with the concentration from 20 g/L to 200 g/L was developed. The fitting area for uranium measurement was determined through experiment. The left fitting area was 1659-1856 channel, and the right one was 2063-2280 channel. The uranium L_Ⅲ--absorption edge was at 1995 channel. The results show that the influence of HNO_3 concentration lower than 9 mol/L, Al and Fe concentration lower than 10 g/L was negligibly small. The uranium measurement precision is better than 0.5%, and the instrument stability is good. Some samples in bench test of uranium recovery were determined. The results are satisfactory. (authors)
Edge Detection from High Resolution Remote Sensing Images using Two-Dimensional log Gabor Filter in Frequency Domain

International Nuclear Information System (INIS)

Wang, K; Yu, T; Meng, Q Y; Wang, G K; Li, S P; Liu, S H

2014-01-01

Edges are vital features to describe the structural information of images, especially high spatial resolution remote sensing images. Edge features can be used to define the boundaries between different ground objects in high spatial resolution remote sensing images. Thus edge detection is important in the remote sensing image processing. Even though many different edge detection algorithms have been proposed, it is difficult to extract the edge features from high spatial resolution remote sensing image including complex ground objects. This paper introduces a novel method to detect edges from the high spatial resolution remote sensing image based on frequency domain. Firstly, the high spatial resolution remote sensing images are Fourier transformed to obtain the magnitude spectrum image (frequency image) by FFT. Then, the frequency spectrum is analyzed by using the radius and angle sampling. Finally, two-dimensional log Gabor filter with optimal parameters is designed according to the result of spectrum analysis. Finally, dot product between the result of Fourier transform and the log Gabor filter is inverse Fourier transformed to obtain the detections. The experimental result shows that the proposed algorithm can detect edge features from the high resolution remote sensing image commendably
Sensitivity of ITER MHD global stability to edge pressure gradients

International Nuclear Information System (INIS)

Hogan, J.T.; Martynov, A.

1994-01-01

In view of the preliminary nature of boundary models for reactor tokamaks, the sensitivity to edge gradients of the global mode MHD stability of the ITER EDA configuration has been examined. The POLAR-2D equilibrium and TORUS stability codes developed by the Keldysh Institute have been used. Transport-related profiles from the PRETOR transport code (developed by the ITER Joint Central Team) and axisymmetric equilibria for these profiles from the TEQ code (L.D. Pearlstein, LLNL) were taken as a starting point for the study. These baseline profiles are found to have quite high global stability limits, in the range g(Troyon) = 4-5. The major focus of this study is to examine global mode stability assuming small variations about the baseline profiles, changing the pressure gradients near the boundary. Such changes can be expected with an improved boundary model. Reduced stability limits are found in such cases, and unstable cases with g = 2-3 are found. Thus, the assumption of ITER stability limits higher than g = 2 must be treated with caution
The roles of long-term phonotactic and lexical prosodic knowledge in phonological short-term memory.

Science.gov (United States)

Tanida, Yuki; Ueno, Taiji; Lambon Ralph, Matthew A; Saito, Satoru

2015-04-01

Many previous studies have explored and confirmed the influence of long-term phonological representations on phonological short-term memory. In most investigations, phonological effects have been explored with respect to phonotactic constraints or frequency. If interaction between long-term memory and phonological short-term memory is a generalized principle, then other phonological characteristics-that is, suprasegmental aspects of phonology-should also exert similar effects on phonological short-term memory. We explored this hypothesis through three immediate serial-recall experiments that manipulated Japanese nonwords with respect to lexical prosody (pitch-accent type, reflecting suprasegmental characteristics) as well as phonotactic frequency (reflecting segmental characteristics). The results showed that phonotactic frequency affected the retention not only of the phonemic sequences, but also of pitch-accent patterns, when participants were instructed to recall both the phoneme sequence and accent pattern of nonwords. In addition, accent pattern typicality influenced the retention of the accent pattern: Typical accent patterns were recalled more accurately than atypical ones. These results indicate that both long-term phonotactic and lexical prosodic knowledge contribute to phonological short-term memory performance.
The interaction of He with 1/2 110 edge dislocation in W and Mo

International Nuclear Information System (INIS)

Hosson, J.Th.M. de; Sleeswyk, A.W.; Caspers, L.M.; Heugten, W. van; Veen, A. van.

1976-01-01

The positions of the metal atoms around a 1/2 [110] edge dislocation in Mo and W are calculated using the Wilson-Johnson potentials. The boundary conditions are given by anisotropic elasticity theory. The He-metal potential, also developed by Wilson and Johnson, is used to calculate the position with maximum energy gain for a He-atom. (author)
Clear Speech - Mere Speech? How segmental and prosodic speech reduction shape the impression that speakers create on listeners

DEFF Research Database (Denmark)

Niebuhr, Oliver

2017-01-01

of reduction levels and perceived speaker attributes in which moderate reduction can make a better impression on listeners than no reduction. In addition to its relevance in reduction models and theories, this interplay is instructive for various fields of speech application from social robotics to charisma...... whether variation in the degree of reduction also has a systematic effect on the attributes we ascribe to the speaker who produces the speech signal. A perception experiment was carried out for German in which 46 listeners judged whether or not speakers showing 3 different combinations of segmental...... and prosodic reduction levels (unreduced, moderately reduced, strongly reduced) are appropriately described by 13 physical, social, and cognitive attributes. The experiment shows that clear speech is not mere speech, and less clear speech is not just reduced either. Rather, results revealed a complex interplay...
Optimization of the poro-serrated trailing edges for airfoil broadband noise reduction.

Science.gov (United States)

Chong, Tze Pei; Dubois, Elisa

2016-08-01

This paper reports an aeroacoustic investigation of a NACA0012 airfoil with a number of poro-serrated trailing edge devices that contain porous materials of various air flow resistances at the gaps between adjacent members of the serrated-sawtooth trailing edge. The main objective of this work is to determine whether multiple-mechanisms on the broadband noise reduction can co-exist on a poro-serrated trailing edge. When the sawtooth gaps are filled with porous material of low-flow resistivity, the vortex shedding tone at low-frequency could not be completely suppressed at high-velocity, but a reasonably good broadband noise reduction can be achieved at high-frequency. When the sawtooth gaps are filled with porous material of very high-flow resistivity, no vortex shedding tone is present, but the serration effect on the broadband noise reduction becomes less effective. An optimal choice of the flow resistivity for a poro-serrated configuration has been identified, where it can surpass the conventional serrated trailing edge of the same geometry by achieving a further 1.5 dB reduction in the broadband noise while completely suppressing the vortex shedding tone. A weakened turbulent boundary layer noise scattering at the poro-serrated trailing edge is reflected by the lower-turbulence intensity at the near wake centreline across the whole spanwise wavelength of the sawtooth.

Theoretical and experimental investigations of stochastic boundaries in tokamaks

International Nuclear Information System (INIS)

Ghendrih, Ph.; Grosman, A.; Capes, H.

1996-01-01

The physics of stochastic boundaries are reviewed. The stochastic properties of magnetic field lines are recalled and related to the spectrum of the radial magnetic perturbation. The stochastic region, referred to as the divertor volume, is shown to be bounded to the edge plasma. Theoretical predictions for the transport of energy, current and particles in the divertor volume are analysed for both the laminar and ergodic regimes. (K.A.)
Transaortic Alfieri Edge-to-Edge Repair for Functional Mitral Regurgitation.

Science.gov (United States)

Imasaka, Ken-Ichi; Tayama, Eiki; Morita, Shigeki; Toriya, Ryohei; Tomita, Yukihiro

2018-03-01

There is controversy about handling functional mitral regurgitation in patients undergoing aortic valve or proximal aortic operations. We describe a transaortic Alfieri edge-to-edge repair for functional mitral regurgitation that reduces operative excessive invasion and prolonged cardiopulmonary bypass time. Between May 2013 and December 2016, 10 patients underwent transaortic Alfieri edge-to-edge mitral repair. There were no operative deaths. The severity of mitral regurgitation immediately after the operation by transesophageal echocardiography was none or trivial in all patients. A transaortic Alfieri edge-to-edge repair for functional mitral regurgitation is a simple and safe approach. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
Leading-Edge Velocities and Lifted Methane Jet Flame Stability

Directory of Open Access Journals (Sweden)

W. Wang

2010-01-01

Full Text Available Current interest exists in understanding reaction-zone dynamics and mechanisms with respect to how they counterpropagate against incoming reactants. Images of flame position and flow-field morphology are presented from flame chemiluminescence and particle image velocimetry (PIV measurements. In the present study, PIV experiments were carried out to measure the methane jet lifted-flame flow-field velocities in the vicinity of the flame leading edge. Specifically, velocity fields within the high-temperature zone were examined in detail, which complements previous studies, whose prime focus is the flow-field upstream of the high-temperature boundary. PIV data is used not only to determine the velocities, but, along with chemiluminescence images, to also indicate the approximate location of the reaction zone (further supported by/through the leading-edge flame velocity distributions. The velocity results indirectly support the concept that the flame is anchored primarily through the mechanism of partially premixed flame propagation.
Suppression of large edge localized modes with a stochastic magnetic boundary in high confinement DIII-D plasmas

Energy Technology Data Exchange (ETDEWEB)

Thomas, P.R.; Boedo, J.A. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Evans, T.E.; Osborne, T.H.; Groebner, R.J.; La Haye, R.J.; Schaffer, M.J.; West, W.P. [General Atomic, San Diego (United States); Moyer, R.A.; Rudakov, D.L. [California Univ., San Diego, La Jolla, CA (United States); Watkins, J.G. [Sandia National Labs., Albuquerque, NM (United States); Fenstermacher, M.E.; Groth, M.; Lasnier, C.J. [Lawrence Livermore National Lab., CA (United States); Finken, K.H. [FZ-Julich Euratom Association, Julich (Germany); Harris, J.H.; Pretty, D.G. [Australian National Univ., Canberra, ACT (Australia); Masuzaki, S.; Ohyabu, N. [National Institute for Fusion Science, Gifu-ken (Japan); Rhodes, T.L.; Wang, G.; Zeng, L. [California Univ., Los Angeles, CA (United States); Reimerdes, H. [Columbia Univ., New York, NY (United States); Wade, M. [Oak Ridge National Lab., TN (United States)

2004-07-01

This work started from the point of view that a robust way of actively suppressing type I ELMs (edge localized modes) is both mandatory and practical in ITER. We report some considerable experimental success in exploring this proposition, using a magnetic perturbation generated by the I-coils in DIII-D. The hypothesis was tested that an external magnetic perturbation, whose toroidal and poloidal spectrum is in resonance with field lines at the edge, increases transport there, reduces the pressure gradient and, thereby, eliminates the drive for the MHD instabilities that cause ELMs. Holding the pressure gradient just below the threshold at which ELMs are triggered, should bring good fusion performance without the penalty of ELMs. (authors)
At the edge of the earth's magnetosphere: a survey by the AMPTE UKS spacecraft

International Nuclear Information System (INIS)

Bryant, D.A.; Riggs, S.

1988-10-01

A survey is made, using measurements from the AMPTE-UKS spacecraft, of the interaction between plasmas of solar and terrestrial origin at the outer edge of the Earth's magnetosphere. The first results are presented of a new type of analysis which aims to clarify the nature of the boundary layer that develops between the two plasmas by re-ordering, on the basis of a consistent relationship between electron density and temperature and the normally erratic progress made by a spacecraft across the constantly moving region. Distinctive patterns found consistently for the electron and ion transitions suggest that diffusion, viscosity and loss to the atmosphere govern the boundary layer. Electron acceleration within the boundary layer is identified; and its cause, and relevance to dayside auroral precipitation are discussed. (author)
Formation of the wave compressional boundary in the earth's foreshock

Science.gov (United States)

Skadron, George; Holdaway, Robert D.; Lee, Martin A.

1988-01-01

Using an evolutionary model and allowing for nonuniform proton injection and wave growth rates, the compressional wave boundaries corresponding to IMF inclinations to the solar wind of theta(BV) equal to 45 and 25 deg were located. The compressional boundaries deduced from this model were found to support the results of Greenstadt and Baum (1986) who have concluded that the observed compressional boundaries are incompatible with wave growth at a fixed growth rate, due to the interaction of a uniform beam with the solar wind. The results indicate, however, that the compressional boundaries are quite compatible with nonuniform beams and growth rates which result from the coupled evolution of the energetic protons and the waves with which they interact. It was found that, in the solar wind frame, the dominant wave-particle interaction in the outer foreshock is the damping of inward propagating (toward the shock) left-polarized waves, producing a magnetically quiet region immediately downstream of the foreshock boundary.
A Method for Extracting Road Boundary Information from Crowdsourcing Vehicle GPS Trajectories.

Science.gov (United States)

Yang, Wei; Ai, Tinghua; Lu, Wei

2018-04-19

Crowdsourcing trajectory data is an important approach for accessing and updating road information. In this paper, we present a novel approach for extracting road boundary information from crowdsourcing vehicle traces based on Delaunay triangulation (DT). First, an optimization and interpolation method is proposed to filter abnormal trace segments from raw global positioning system (GPS) traces and interpolate the optimization segments adaptively to ensure there are enough tracking points. Second, constructing the DT and the Voronoi diagram within interpolated tracking lines to calculate road boundary descriptors using the area of Voronoi cell and the length of triangle edge. Then, the road boundary detection model is established integrating the boundary descriptors and trajectory movement features (e.g., direction) by DT. Third, using the boundary detection model to detect road boundary from the DT constructed by trajectory lines, and a regional growing method based on seed polygons is proposed to extract the road boundary. Experiments were conducted using the GPS traces of taxis in Beijing, China, and the results show that the proposed method is suitable for extracting the road boundary from low-frequency GPS traces, multi-type road structures, and different time intervals. Compared with two existing methods, the automatically extracted boundary information was proved to be of higher quality.
A Method for Extracting Road Boundary Information from Crowdsourcing Vehicle GPS Trajectories

Directory of Open Access Journals (Sweden)

Wei Yang

2018-04-01

Full Text Available Crowdsourcing trajectory data is an important approach for accessing and updating road information. In this paper, we present a novel approach for extracting road boundary information from crowdsourcing vehicle traces based on Delaunay triangulation (DT. First, an optimization and interpolation method is proposed to filter abnormal trace segments from raw global positioning system (GPS traces and interpolate the optimization segments adaptively to ensure there are enough tracking points. Second, constructing the DT and the Voronoi diagram within interpolated tracking lines to calculate road boundary descriptors using the area of Voronoi cell and the length of triangle edge. Then, the road boundary detection model is established integrating the boundary descriptors and trajectory movement features (e.g., direction by DT. Third, using the boundary detection model to detect road boundary from the DT constructed by trajectory lines, and a regional growing method based on seed polygons is proposed to extract the road boundary. Experiments were conducted using the GPS traces of taxis in Beijing, China, and the results show that the proposed method is suitable for extracting the road boundary from low-frequency GPS traces, multi-type road structures, and different time intervals. Compared with two existing methods, the automatically extracted boundary information was proved to be of higher quality.
Modeling of the heat transfer in bypass transitional boundary-layer flows

Science.gov (United States)

Simon, Frederick F.; Stephens, Craig A.

1991-01-01

A low Reynolds number k-epsilon turbulence model and conditioned momentum, energy and turbulence equations were used to predict bypass transition heat transfer on a flat plate in a high-disturbance environment with zero pressure gradient. The use of conditioned equations was demonstrated to be an improvement over the use of the global-time-averaged equations for the calculation of velocity profiles and turbulence intensity profiles in the transition region of a boundary layer. The approach of conditioned equations is extended to include heat transfer and a modeling of transition events is used to predict transition onset and the extent of transition on a flat plate. The events, which describe the boundary layer at the leading edge, result in boundary-layer regions consisting of: (1) the laminar, (2) pseudolaminar, (3) transitional, and (4) turbulent boundary layers. The modeled transition events were incorporated into the TEXSTAN 2-D boundary-layer code which is used to numerically predict the heat transfer. The numerical predictions in general compared well with the experimental data and revealed areas where additional experimental information is needed.
Edge-functionalization of armchair graphene nanoribbons with pentagonal-hexagonal edge structures.

Science.gov (United States)

Ryou, Junga; Park, Jinwoo; Kim, Gunn; Hong, Suklyun

2017-06-21

Using density functional theory calculations, we have studied the edge-functionalization of armchair graphene nanoribbons (AGNRs) with pentagonal-hexagonal edge structures. While the AGNRs with pentagonal-hexagonal edge structures (labeled (5,6)-AGNRs) are metallic, the edge-functionalized (5,6)-AGNRs with substitutional atoms opens a band gap. We find that the band structures of edge-functionalized (5,6)-N-AGNRs by substitution resemble those of defect-free (N-1)-AGNR at the Γ point, whereas those at the X point show the original ones of the defect-free N-AGNR. The overall electronic structures of edge-functionalized (5,6)-AGNRs depend on the number of electrons, supplied by substitutional atoms, at the edges of functionalized (5,6)-AGNRs.
Flow Phenomena in the Very Near Wake of a Flat Plate with a Circular Trailing Edge

Science.gov (United States)

Rai, Man Mohan

2014-01-01

The very near wake of a flat plate with a circular trailing edge, exhibiting pronounced shedding of wake vortices, is investigated with data from a direct numerical simulation. The separating boundary layers are turbulent and statistically identical thus resulting in a wake that is symmetric in the mean. The focus here is on the instability of the detached shear layers, the evolution of rib-vortex induced localized regions of reverse flow that detach from the main body of reverse flow in the trailing edge region and convect downstream, and phaseaveraged velocity statistics in the very near wake. The detached shear layers are found to exhibit unstable behavior intermittently, including the development of shear layer vortices as in earlier cylinder flow investigations with laminar separating boundary layers. Only a small fraction of the separated turbulent boundary layers undergo this instability, and form the initial shed vortices. Pressure spectra within the shear layers show a broadband peak at a multiple of shedding frequency. Phase-averaged intensity and shear stress distributions of the randomly fluctuating component of velocity are compared with those obtained in the near wake. The distributions of the production terms in the transport equations for the turbulent stresses are also provided.
Modelling the possible interaction between edge-driven convection and the Canary Islands mantle plume

Science.gov (United States)

Negredo, A. M.; Rodríguez-González, J.; Fullea, J.; Van Hunen, J.

2017-12-01

The close location between many hotspots and the edges of cratonic lithosphere has led to the hypothesis that these hotspots could be explained by small-scale mantle convection at the edge of cratons (Edge Driven Convection, EDC). The Canary Volcanic Province hotspot represents a paradigmatic example of this situation due to its close location to the NW edge of the African Craton. Geochemical evidence, prominent low seismic velocity anomalies in the upper and lower mantle, and the rough NE-SW age-progression of volcanic centers consistently point out to a deep-seated mantle plume as the origin of the Canary Volcanic Province. It has been hypothesized that the plume material could be affected by upper mantle convection caused by the thermal contrast between thin oceanic lithosphere and thick (cold) African craton. Deflection of upwelling blobs due to convection currents would be responsible for the broader and more irregular pattern of volcanism in the Canary Province compared to the Madeira Province. In this study we design a model setup inspired on this scenario to investigate the consequences of possible interaction between ascending mantle plumes and EDC. The Finite Element code ASPECT is used to solve convection in a 2D box. The compositional field and melt fraction distribution are also computed. Free slip along all boundaries and constant temperature at top and bottom boundaries are assumed. The initial temperature distribution assumes a small long-wavelength perturbation. The viscosity structure is based on a thick cratonic lithosphere progressively varying to a thin, or initially inexistent, oceanic lithosphere. The effects of assuming different rheologies, as well as steep or gradual changes in lithospheric thickness are tested. Modelling results show that a very thin oceanic lithosphere (models assuming temperature-dependent viscosity and large viscosity variations evolve to large-scale (upper mantle) convection cells, with upwelling of hot material being
Direct Numerical Simulation of an Airfoil with Sand Grain Roughness on the Leading Edge

Science.gov (United States)

Ribeiro, Andre F. P.; Casalino, Damiano; Fares, Ehab; Choudhari, Meelan

2016-01-01

As part of a computational study of acoustic radiation due to the passage of turbulent boundary layer eddies over the trailing edge of an airfoil, the Lattice-Boltzmann method is used to perform direct numerical simulations of compressible, low Mach number flow past an NACA 0012 airfoil at zero degrees angle of attack. The chord Reynolds number of approximately 0.657 million models one of the test conditions from a previous experiment by Brooks, Pope, and Marcolini at NASA Langley Research Center. A unique feature of these simulations involves direct modeling of the sand grain roughness on the leading edge, which was used in the abovementioned experiment to trip the boundary layer to fully turbulent flow. This report documents the findings of preliminary, proof-of-concept simulations based on a narrow spanwise domain and a limited time interval. The inclusion of fully-resolved leading edge roughness in this simulation leads to significantly earlier transition than that in the absence of any roughness. The simulation data is used in conjunction with both the Ffowcs Williams-Hawkings acoustic analogy and a semi-analytical model by Roger and Moreau to predict the farfield noise. The encouraging agreement between the computed noise spectrum and that measured in the experiment indicates the potential payoff from a full-fledged numerical investigation based on the current approach. Analysis of the computed data is used to identify the required improvements to the preliminary simulations described herein.
Molecular dynamics simulation of edge dislocation piled at cuboidal precipitate in Ni-based superalloy

International Nuclear Information System (INIS)

Yashiro, Kisaragi; Naito, Masato; Tomita, Yoshihiro

2003-01-01

In order to clarify the fundamental mechanism of dislocations in the γ/γ' microstructure of Ni-based superalloy, three molecular dynamics simulations are conducted on the behavior of edge dislocations nucleated from a free surface and proceeding in the pure Ni matrix (γ) toward cuboidal Ni 3 Al precipitates (γ') under shear force. One involves dislocations near the apices of two precipitates adjoining each other with the distance of 0.04 μm, as large as the width of the γ channel in real superalloys. Others simulate dislocations piled at the precipitates as well, however, the scale of the microstructure is smaller than that in real superalloys by one order of magnitude, and one of them have precipitates with atomistically sharp edge. Dislocations are pinned at precipitates and bowed-out in the γ channel, then they begin to penetrate into the precipitate at the edge in both the real-scale and smaller microstructures when the precipitates have blunt edges. On the other hand, an edge dislocation splits into a superpartial in the γ' precipitate and a misfit screw dislocation bridging between two adjacent precipitates at the atomistically sharp edge of γ' precipitates. It is also observed that two superpartials glide in the precipitate as a superdislocation with anti-phase boundary (APB), of which the width is evaluated to be about 4 nm. (author)
Edge passivation induced single-edge ferromagnetism of zigzag MoS_2 nanoribbons

International Nuclear Information System (INIS)

Wang, Rui; Sun, Hui; Ma, Ben; Hu, Jingguo; Pan, Jing

2017-01-01

We performed density functional theory study on electronic structure, magnetic properties and stability of zigzag MoS_2 nanoribbons (ZMoS_2NRs) with and without oxygen (O) passivation. The bare ZMoS_2NRs are magnetic metal with ferromagnetic edge states, edge passivation decreases their magnetism because of the decrease of edge unsaturated electrons. Obviously, the electronic structure and magnetic properties of ZMoS_2NRs greatly depend on edge states. When both edges are passivated by O atoms, ZMoS_2NRs are nonmagnetic metals. When either edge is passivated by O atoms, the systems exhibit single-edge ferromagnetism and magnetism concentrates on the non-passivated edge. Edge passivation can not only tune the magnetism of ZMoS_2NRs, but also enhance their stability by eliminating dangling bonds. These interesting findings on ZMoS_2NRs may open the possibility of their application in nanodevices and spintronics. - Highlights: • Edge passivation for tuning magnetism of zigzag MoS_2 nanoribbons (ZMoS_2NRs) is proposed. • Edge passivation can tune ZMoS_2NRs from nonmagnetic metal to ferromagnetic metal. • When either edge is passivated, the systems exhibit single-edge ferromagnetic states. • These findings may inspire great interest in the community of ZMoS_2NRs and motivate numerous experimental researches.
Using Convolutional Neural Network Filters to Measure Left-Right Mirror Symmetry in Images

Directory of Open Access Journals (Sweden)

Anselm Brachmann

2016-12-01

Full Text Available We propose a method for measuring symmetry in images by using filter responses from Convolutional Neural Networks (CNNs. The aim of the method is to model human perception of left/right symmetry as closely as possible. Using the Convolutional Neural Network (CNN approach has two main advantages: First, CNN filter responses closely match the responses of neurons in the human visual system; they take information on color, edges and texture into account simultaneously. Second, we can measure higher-order symmetry, which relies not only on color, edges and texture, but also on the shapes and objects that are depicted in images. We validated our algorithm on a dataset of 300 music album covers, which were rated according to their symmetry by 20 human observers, and compared results with those from a previously proposed method. With our method, human perception of symmetry can be predicted with high accuracy. Moreover, we demonstrate that the inclusion of features from higher CNN layers, which encode more abstract image content, increases the performance further. In conclusion, we introduce a model of left/right symmetry that closely models human perception of symmetry in CD album covers.
Cross-sectional scanning tunneling microscopy of antiphase boundaries in epitaxially grown GaP layers on Si(001)

Energy Technology Data Exchange (ETDEWEB)

Prohl, Christopher; Lenz, Andrea, E-mail: alenz@physik.tu-berlin.de [Technische Universität Berlin, Institut für Festkörperphysik, 10623 Berlin (Germany); Döscher, Henning; Kleinschmidt, Peter; Hannappel, Thomas [Helmholtz Center Berlin for Materials and Energy, 14109 Berlin (Germany)

2016-05-15

In a fundamental cross-sectional scanning tunneling microscopy investigation on epitaxially grown GaP layers on a Si(001) substrate, differently oriented antiphase boundaries are studied. They can be identified by a specific contrast and by surface step edges starting/ending at the position of an antiphase boundary. Moreover, a change in the atomic position of P and Ga atoms along the direction of growth is observed in agreement with the structure model of antiphase boundaries in the GaP lattice. This investigation opens the perspective to reveal the orientation and position of the antiphase boundaries at the atomic scale due to the excellent surface sensitivity of this method.
Development of automatic extraction method of left ventricular contours on long axis view MR cine images

International Nuclear Information System (INIS)

Utsunomiya, Shinichi; Iijima, Naoto; Yamasaki, Kazunari; Fujita, Akinori

1995-01-01

In the MRI cardiac function analysis, left ventricular volume curves and diagnosis parameters are obtained by extracting the left ventricular cavities as regions of interest (ROI) from long axis view MR cine images. The ROI extractions had to be done by manual operations, because automatization of the extraction is difficult. A long axis view left ventricular contour consists of a cardiac wall part and an aortic valve part. The above mentioned difficulty is due to the decline of contrast on the cardiac wall part, and the disappearance of edge on the aortic valve part. In this paper, we report a new automatic extraction method for long axis view MR cine images, which needs only 3 manually indicated points on the 1st image to extract all the contours from the total sequence of images. At first, candidate points of a contour are detected by edge detection. Then, selecting the best matched combination of candidate points by Dynamic Programming, the cardiac wall part is automatically extracted. The aortic valve part is manually extracted for the 1st image by indicating both the end points, and is automatically extracted for the rest of the images, by utilizing the aortic valve motion characteristics throughout a cardiac cycle. (author)
Numerical analysis of the impact of permeability on trailing-edge noise

Science.gov (United States)

Koh, Seong Ryong; Meinke, Matthias; Schröder, Wolfgang

2018-05-01

The impact of porous surfaces on the near-wall turbulent structures and the generated trailing-edge noise is analyzed for several trailing-edge shapes of finite thickness using a high resolution large-eddy simulation (LES)/computational aeroacoustics (CAA) method. The porous surface of the trailing edge is defined by the porosity and the viscous permeability determined by the solution of a turbulent flat plate boundary layer at a Reynolds number 1280 based on the displacement thickness in the inflow cross section. The volume-averaged approach for the homogeneous porous medium shows that the porous impedance scales linearly with the porosity and exponentially with the mean structure size of a porous medium. The drag induced by the porous surface changes the friction velocity and the permeability Reynolds number ReK which determines the porous impedance Rs scaled by ReK-2/3. The trailing-edge noise is analyzed for three solid and three porous trailing edges. The effect of a finite span is investigated by the spanwise correlation model based on the measured coherence distribution. The acoustic prediction shows a good agreement with measurements of the broadband spectrum and the strong tone generated by a finite trailing-edge thickness. The pressure gradient inside the porous media is redistributed by the Darcy drag defined by the viscous permeability and the porosity. The mean pressure increases in the upstream direction inside the porous medium such that the flow acceleration involved in the acoustic generation is reduced inside the porous medium. The noise reduction by a porous medium reaches 11 dB for the trailing-edge shape which possesses a sharp corner for the solid surface. The porous surface applied to a semi-circular trailing edge achieves a 4 dB noise reduction. The directivity pattern for individual components of the acoustic spectrum shows that the massive noise reduction is determined at the tone. Enhanced wave diffraction by the thick flat plate changes
Edge localized modes control: experiment and theory

International Nuclear Information System (INIS)

Becoulet, M.; Huysmans, G.; Thomas, P.; Joffrin, E.; Rimini, F.; Monier-Garbet, P.; Grosman, A.; Ghendrih, P.; Parail, V.; Lomas, P.; Matthews, G.; Wilson, H.; Gryaznevich, M.; Counsell, G.; Loarte, A.; Saibene, G.; Sartori, R.; Leonard, A.; Snyder, P.; Evans, T.; Gohil, P.; Moyer, R.; Kamada, Y.; Oyama, N.; Hatae, T.; Kamiya, K.; Degeling, A.; Martin, Y.; Lister, J.; Rapp, J.; Perez, C.; Lang, P.; Chankin, A; Eich, T.; Sips, A.; Stober, J.; Horton, L.; Kallenbach, A.; Suttrop, W.; Saarelma, S.; Cowley, S.; Loennroth, J.; Shimada, M.; Polevoi, A.; Federici, G.

2005-01-01

The paper reviews recent theoretical and experimental results focussing on the identification of the key factors controlling ELM energy and particle losses both in natural ELMs and in the presence of external controlling mechanisms. Present experiment and theory pointed out the benefit of the high plasma shaping, high q 95 and high pedestal density in reducing the ELM affected area and conductive energy losses in Type I ELMs. Small benign ELMs regimes in present machines (EDA, HRS, Type II, Grassy, QH, Type III in impurity seeded discharges at high δ ) and their relevance for ITER are reviewed. Recent studies of active control of ELMs using stochastic boundaries, small pellets and edge current generation are presented

Education Demographic and Geographic Estimates Program (EDGE): Locale Boundaries User's Manual. NCES 2016-012

Science.gov (United States)

Geverdt, Douglas E.

2015-01-01

The National Center for Education Statistics (NCES) Education Demographic and Geographic Estimates (EDGE) program develops geographic data to help policymakers, program administrators, and the public understand relationships between educational institutions and the communities they serve. One of the commonly used geographic data items is the NCES…
Turbulence induced radial transport of toroidal momentum in boundary plasma of EAST tokamak

International Nuclear Information System (INIS)

Zhao, N.; Yan, N.; Xu, G. S.; Wang, H. Q.; Wang, L.; Ding, S. Y.; Chen, R.; Chen, L.; Zhang, W.; Hu, G. H.; Shao, L. M.; Wang, Z. X.

2016-01-01

Turbulence induced toroidal momentum transport in boundary plasma is investigated in H-mode discharge using Langmuir-Mach probes on EAST. The Reynolds stress is found to drive an inward toroidal momentum transport, while the outflow of particles convects the toroidal momentum outwards in the edge plasma. The Reynolds stress driven momentum transport dominates over the passive momentum transport carried by particle flux, which potentially provides a momentum source for the edge plasma. The outflow of particles delivers a momentum flux into the scrape-off layer (SOL) region, contributing as a momentum source for the SOL flows. At the L-H transitions, the outward momentum transport suddenly decreases due to the suppression of edge turbulence and associated particle transport. The SOL flows start to decelerate as plasma entering into H-mode. The contributions from turbulent Reynolds stress and particle transport for the toroidal momentum transport are identified. These results shed lights on the understanding of edge plasma accelerating at L-H transitions.
Automated kidney morphology measurements from ultrasound images using texture and edge analysis

Science.gov (United States)

Ravishankar, Hariharan; Annangi, Pavan; Washburn, Michael; Lanning, Justin

2016-04-01

In a typical ultrasound scan, a sonographer measures Kidney morphology to assess renal abnormalities. Kidney morphology can also help to discriminate between chronic and acute kidney failure. The caliper placements and volume measurements are often time consuming and an automated solution will help to improve accuracy, repeatability and throughput. In this work, we developed an automated Kidney morphology measurement solution from long axis Ultrasound scans. Automated kidney segmentation is challenging due to wide variability in kidney shape, size, weak contrast of the kidney boundaries and presence of strong edges like diaphragm, fat layers. To address the challenges and be able to accurately localize and detect kidney regions, we present a two-step algorithm that makes use of edge and texture information in combination with anatomical cues. First, we use an edge analysis technique to localize kidney region by matching the edge map with predefined templates. To accurately estimate the kidney morphology, we use textural information in a machine learning algorithm framework using Haar features and Gradient boosting classifier. We have tested the algorithm on 45 unseen cases and the performance against ground truth is measured by computing Dice overlap, % error in major and minor axis of kidney. The algorithm shows successful performance on 80% cases.
Inversion domain boundaries in GaN studied by X-ray microprobe

Energy Technology Data Exchange (ETDEWEB)

Martinez-Criado, Gema; Tucoulou, Remi; Cloetens, Peter; Sans, Juan Angel; Susini, Jean [European Synchrotron Radiation Facility, Experiments Division, Grenoble (France); Somogyi, Andrea [Experiments Division, Synchrotron SOLEIL, Gif-sur-Yvette (France); Alen, Benito [Microelectronics Institute Madrid, CNM-CSIC, Madrid (Spain); Miskys, Claudio [Walter Schottky Institute, Technical University Munich, Garching (Germany)

2010-02-15

In this study, we report on the application of synchrotron spectro-microscopic techniques to the examination of inversion domain boundaries formed intentionally in a GaN-based lateral polarity heterostructure. Using X-ray sub-microbeams, no evidence of field-driven electrodiffusion effects has been observed on spatially separated inversion domain boundaries. In addition, XANES data around the Ga K-edge strongly supported hexagonal Ga site configurations, suggesting high local order reconstruction. Based on inner-shell excited luminescence on the micrometer scale, the uniform spectral distribution of the radiative centers was discussed. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Expanded-boundary approach to impurity control in tokamaks

International Nuclear Information System (INIS)

Ohyabu, N.

1981-01-01

It is proposed to expand the outermost flux surfaces in tokamaks to divert the heat flux emerging from the plasma core. The expanded flux surfaces provide a large volume for radiative cooling. The radiative power at the boundary is enhanced by the effects of plasma flow as well as by a volumetric factor, and the resultant edge cooling and reduced heat load on the limiter may significantly retard impurity generation. Furthermore, it seems to be compatible with reactor engineering requirements. (author)
An evaluation of edge effects in nutritional accessibility and availability measures: a simulation study.

Science.gov (United States)

Van Meter, Emily M; Lawson, Andrew B; Colabianchi, Natalie; Nichols, Michele; Hibbert, James; Porter, Dwayne E; Liese, Angela D

2010-07-27

This paper addresses the statistical use of accessibility and availability indices and the effect of study boundaries on these measures. The measures are evaluated via an extensive simulation based on cluster models for local outlet density. We define outlet to mean either food retail store (convenience store, supermarket, gas station) or restaurant (limited service or full service restaurants). We designed a simulation whereby a cluster outlet model is assumed in a large study window and an internal subset of that window is constructed. We performed simulations on various criteria including one scenario representing an urban area with 2000 outlets as well as a non-urban area simulated with only 300 outlets. A comparison is made between estimates obtained with the full study area and estimates using only the subset area. This allows the study of the effect of edge censoring on accessibility measures. The results suggest that considerable bias is found at the edges of study regions in particular for accessibility measures. Edge effects are smaller for availability measures (when not smoothed) and also for short range accessibility It is recommended that any study utilizing these measures should correct for edge effects. The use of edge correction via guard areas is recommended and the avoidance of large range distance-based accessibility measures is also proposed.
MHD forced and free convection boundary layer flow near the leading edge

International Nuclear Information System (INIS)

Hossain, M.A.; Ahmed, M.

1988-07-01

Magnetohydrodynamic forced and free convection flow of an electrically conducting viscous incompressible fluid past a vertical flat plate with uniform heat flux in the presence of a magnetic field acting normal to the plate that moves with the fluid has been studied near the leading edge of the plate. The coupled non-linear equations are solved by the method of superposition for the values of the Prandtl number ranges from 0.01 to 10.0. The velocity and the temperature profiles are presented graphically and the values of the wall shear-stress as well as the heat transfer rate are presented in tabular form showing the effect of the buoyancy force and the applied magnetic field. To show the accuracy of the present method some typical values are compared with the available one. (author). 17 refs, 3 figs, 2 tabs
Edge effects on understory epiphytic ferns and epiphyllous bryophytes in moist afromontane forests of Ethiopia

Directory of Open Access Journals (Sweden)

Hylander Kristoffer

2013-12-01

Full Text Available Most studies on edge effects in tropical forests have been conducted in landscapes with low human population density and in situations where the edges have been left unused after logging of the adjacent area. Here we studied forest margins heavily used by local farmers in a forest/agriculture mosaic landscape in Ethiopia. We compared forest structure and plant species composition across 41 forest-agriculture ecotones from 200 m out into the agricultural area to 200 m into the forest. There are strong edge effects from the edge and into the forest on canopy cover and number of stumps and apparently these forest-agricultural edges are intensively used by humans. They are penetrated by paths, beehives are found in the trees, timber of various dimensions is harvested and there is sometimes substantial cover of perennial wild (or semi-wild crops such as coffee and spices. The number of understory epiphytic fern species as well as number of epiphyllous (i.e., growing on leaves bryophyte species was lower at 20 m than at 75 m from the edge. The number of fern species was higher in newly created edges and thereafter they declined, which indicates an extinction debt. This pattern was not seen for the epiphyllous bryophytes. It is likely that different human management activities are responsible for many of the found edge effects besides wind and sun effects from the edge. Tropical forest margins provide important resources for people in many landscapes. It is important to understand how such use affects the biota of the forests. This study shows that there are substantial edge effects, but that the edge effects do not seem to become worse over time for epiphyllous bryophytes and only slightly so for ferns.
Investigation of E x B transport with a multi-electrode probe in the plasma boundary of TEXTOR

International Nuclear Information System (INIS)

Ivanov, R.S.; Moyer, R.A.; Nieuwenhove, R. van; Oost, G. van; Fuchs, G.; Hoethker, K.; Samm, U.

1991-01-01

A movable multi-element Langmuir probe was implemented in TEXTOR in order to study properties of the edge and scrape-off plasma. The probe has five graphite electrode pins allowing the simultaneous measurement of main parameters such as plasma densities, electron temperatures, floating potentials, poloidal and radial electric fields. Both time-averaged and fluctuating quantities have been considered in order to evaluate the DC and turbulence-driven cross-field particle fluxes. The spectral analysis of the fluctuating floating potentials at spatially separated probe pins allows to determine the velocity associated with the rotations of the boundary plasma. The investigations have been focused on the variations of plasma boundary properties in plasmas with pure ohmic heating as well as auxiliary heating (ICRH). Special attention has been paid to the change of transport properties with the transition to a detached plasma. In particular, a significant reduction of the poloidal phase velocity at the limited edge has been observed for detached plasmas. Preliminary data on physical effects near the plasma boundary, which occur when the toroidal belt limiter (ALT-II) is biased, are reported. (orig.)
Accuracy of gated equilibrium radioventriculography in measuring left ventricular function in dogs

International Nuclear Information System (INIS)

Valette, H.; Bourguignon, M.H.; Apoil, E.; Syrota, A.; Moyse, D.; Wise, R.A.; Buchanan, J.W.; Wagner, H.N. Jr.

1988-01-01

To assess the precision of gated equilibrium radioventriculography in measuring changes in left ventricular stroke volume (LVSV), we studied five dogs each with a chronically implanted electromagnetic flowmeter on the ascending aorta. Per cent changes in left ventricular stroke counts (LVSC) were compared to those in LVSV following acute changes induced by positive end respiratory pressure. We have compared LVSCs calculated in five different ways: (1) Manual outlining of LV region of interest (LVROI), either single fixed enddiastolic (ED) ROI or ED and end-systolic (ES) ROIs with the aid of functional images (first harmonic of Fourier analysis); (2-5) automatic outlining of LV ROI (the algorithm generated 30 profiles on which the maximum of second derivative delineated the LV edges) was performed either on ED image or both ED and ES images. For these four methods a crescent-shaped ROI for background correction was manually drawn at the border of the LV ROI. The fifth method used an automatically drawn single fixed LVED ROI with interpolative background substraction (IBS) between LV and RV edges. LVSC changes, calculated with the IBS method, correlated better with LVSV changes than the other four methods. Thus assessment of small LVSC changes is highly processing-dependent. (author)
On the edge of language acquisition: inherent constraints on encoding multisyllabic sequences in the neonate brain.

Science.gov (United States)

Ferry, Alissa L; Fló, Ana; Brusini, Perrine; Cattarossi, Luigi; Macagno, Francesco; Nespor, Marina; Mehler, Jacques

2016-05-01

To understand language, humans must encode information from rapid, sequential streams of syllables - tracking their order and organizing them into words, phrases, and sentences. We used Near-Infrared Spectroscopy (NIRS) to determine whether human neonates are born with the capacity to track the positions of syllables in multisyllabic sequences. After familiarization with a six-syllable sequence, the neonate brain responded to the change (as shown by an increase in oxy-hemoglobin) when the two edge syllables switched positions but not when two middle syllables switched positions (Experiment 1), indicating that they encoded the syllables at the edges of sequences better than those in the middle. Moreover, when a 25 ms pause was inserted between the middle syllables as a segmentation cue, neonates' brains were sensitive to the change (Experiment 2), indicating that subtle cues in speech can signal a boundary, with enhanced encoding of the syllables located at the edges of that boundary. These findings suggest that neonates' brains can encode information from multisyllabic sequences and that this encoding is constrained. Moreover, subtle segmentation cues in a sequence of syllables provide a mechanism with which to accurately encode positional information from longer sequences. Tracking the order of syllables is necessary to understand language and our results suggest that the foundations for this encoding are present at birth. © 2015 John Wiley & Sons Ltd.
Transient thermal stress analysis of a near-edge elliptical defect in a semi-infinite plate subjected to a moving heat source

International Nuclear Information System (INIS)

Mingjong Wang; Weichung Wang

1994-01-01

In this paper, the maximum transient thermal stresses on the boundary of a near-edge elliptical defect in a semi-infinite thin plate were determined by the digital photoelastic technique, when the plate edge experiences a moving heat source. The relationships between the maximum transient thermal stresses and the size and inclination of the elliptical defect, the minimum distance from the elliptical defect to the plate edge as well as the speed of the moving heat source were also studied. Finally, by using a statistical analysis package, the variations of the maximum transient thermal stresses were then correlated with the time, the minimum distance between the edge and the elliptical defect, temperature difference, and speed of the moving heat source. (author)
Recognition of facial expressions and prosodic cues with graded emotional intensities in adults with Asperger syndrome.

Science.gov (United States)

Doi, Hirokazu; Fujisawa, Takashi X; Kanai, Chieko; Ohta, Haruhisa; Yokoi, Hideki; Iwanami, Akira; Kato, Nobumasa; Shinohara, Kazuyuki

2013-09-01

This study investigated the ability of adults with Asperger syndrome to recognize emotional categories of facial expressions and emotional prosodies with graded emotional intensities. The individuals with Asperger syndrome showed poorer recognition performance for angry and sad expressions from both facial and vocal information. The group difference in facial expression recognition was prominent for stimuli with low or intermediate emotional intensities. In contrast to this, the individuals with Asperger syndrome exhibited lower recognition accuracy than typically-developed controls mainly for emotional prosody with high emotional intensity. In facial expression recognition, Asperger and control groups showed an inversion effect for all categories. The magnitude of this effect was less in the Asperger group for angry and sad expressions, presumably attributable to reduced recruitment of the configural mode of face processing. The individuals with Asperger syndrome outperformed the control participants in recognizing inverted sad expressions, indicating enhanced processing of local facial information representing sad emotion. These results suggest that the adults with Asperger syndrome rely on modality-specific strategies in emotion recognition from facial expression and prosodic information.
Power spectrum weighted edge analysis for straight edge detection in images

Science.gov (United States)

Karvir, Hrishikesh V.; Skipper, Julie A.

2007-04-01

Most man-made objects provide characteristic straight line edges and, therefore, edge extraction is a commonly used target detection tool. However, noisy images often yield broken edges that lead to missed detections, and extraneous edges that may contribute to false target detections. We present a sliding-block approach for target detection using weighted power spectral analysis. In general, straight line edges appearing at a given frequency are represented as a peak in the Fourier domain at a radius corresponding to that frequency, and a direction corresponding to the orientation of the edges in the spatial domain. Knowing the edge width and spacing between the edges, a band-pass filter is designed to extract the Fourier peaks corresponding to the target edges and suppress image noise. These peaks are then detected by amplitude thresholding. The frequency band width and the subsequent spatial filter mask size are variable parameters to facilitate detection of target objects of different sizes under known imaging geometries. Many military objects, such as trucks, tanks and missile launchers, produce definite signatures with parallel lines and the algorithm proves to be ideal for detecting such objects. Moreover, shadow-casting objects generally provide sharp edges and are readily detected. The block operation procedure offers advantages of significant reduction in noise influence, improved edge detection, faster processing speed and versatility to detect diverse objects of different sizes in the image. With Scud missile launcher replicas as target objects, the method has been successfully tested on terrain board test images under different backgrounds, illumination and imaging geometries with cameras of differing spatial resolution and bit-depth.
Watershed-based Image Segmentation with Region Merging and Edge Detection

Institute of Scientific and Technical Information of China (English)

无

2003-01-01

The clustering technique is used to examine each pixel in the image which assigned to one of the clusters depending on the minimum distance to obtain primary classified image into different intensity regions. A watershed transformation technique is then employes. This includes: gradient of the classified image, dividing the image into markers, checking the Marker Image to see if it has zero points (watershed lines). The watershed lines are then deleted in the Marker Image created by watershed algorithm. A Region Adjacency Graph (RAG) and Region Adjacency Boundary (RAB) are created between two regions from Marker Image. Finally region merging is done according to region average intensity and two edge strengths (T1, T2). The approach of the authors is tested on remote sensing and brain MR medical images. The final segmentation result is one closed boundary per actual region in the image.
Vortex Shedding Characteristics of the Wake of a Thin Flat Plate with a Circular Trailing Edge

Science.gov (United States)

Rai, Man Mohan

2018-01-01

The near and very near wake of a thin flat plate with a circular trailing edge are investigated with direct numerical simulations (DNS). Data obtained for two different Reynolds numbers (based on plate thickness, D) are the main focus of this study. The separating boundary layers are turbulent in both cases. An earlier investigation of one of the cases (Case F) showed shed vortices in the wake that were about 1.0 D to 4.0 D in spanwise length. Considerable variation in both the strength and frequency of these shed vortices was observed. One objective of the present investigation is to determine the important contributors to this variability in strength and frequency of shed vortices and their finite spanwise extent. Analysis of the data shows that streamwise vortices in the separating boundary layer play an important role in strengthening/weakening of the shed vortices and that high/low-speed streaks in the boundary layer are important contributors to variability in shedding frequency. Both these features of the boundary layer contribute to the finite extent of the vortices in the spanwise direction. The second plate DNS (Case G, with 40 percent of the plate thickness of Case F) shows that while shedding intensity is weaker than obtained in Case F, many of the wake features are similar to that of Case F. This is important in understanding the path to the wake of the thin plate with a sharp trailing edge where shedding is absent. Here we also test the efficacy of a functional relationship between the shedding frequency and the Reynolds numbers based on the boundary layer momentum thickness (Re (sub theta) and D (Re (sub D)); data for developing this behavioral model is from Cases F & G and five earlier DNSs of the flat plate wake.
Edge states in the climate system: exploring global instabilities and critical transitions

Science.gov (United States)

Lucarini, Valerio; Bódai, Tamás

2017-07-01

Multistability is a ubiquitous feature in systems of geophysical relevance and provides key challenges for our ability to predict a system’s response to perturbations. Near critical transitions small causes can lead to large effects and—for all practical purposes—irreversible changes in the properties of the system. As is well known, the Earth climate is multistable: present astronomical and astrophysical conditions support two stable regimes, the warm climate we live in, and a snowball climate characterized by global glaciation. We first provide an overview of methods and ideas relevant for studying the climate response to forcings and focus on the properties of critical transitions in the context of both stochastic and deterministic dynamics, and assess strengths and weaknesses of simplified approaches to the problem. Following an idea developed by Eckhardt and collaborators for the investigation of multistable turbulent fluid dynamical systems, we study the global instability giving rise to the snowball/warm multistability in the climate system by identifying the climatic edge state, a saddle embedded in the boundary between the two basins of attraction of the stable climates. The edge state attracts initial conditions belonging to such a boundary and, while being defined by the deterministic dynamics, is the gate facilitating noise-induced transitions between competing attractors. We use a simplified yet Earth-like intermediate complexity climate model constructed by coupling a primitive equations model of the atmosphere with a simple diffusive ocean. We refer to the climatic edge states as Melancholia states and provide an extensive analysis of their features. We study their dynamics, their symmetry properties, and we follow a complex set of bifurcations. We find situations where the Melancholia state has chaotic dynamics. In these cases, we have that the basin boundary between the two basins of attraction is a strange geometric set with a nearly zero
Characterisation of the ELM synchronized H-mode edge pedestal in ASDEX upgrade and DIII-D

Energy Technology Data Exchange (ETDEWEB)

Schneider, Philip A.; Wolfrum, Elisabeth; Guenter, Sibylle; Kurzan, Bernd; Zohm, Hartmut [Max Planck Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Groebner, Rich; Osborne, Tom H.; Ferron, John; Snyder, Philip B. [General Atomics, San Diego, CA (United States); Dunne, Mike G. [Department of Physics, University College Cork, Association Euratom-DCU, Cork (Ireland); Collaboration: ASDEX Upgrade Team; DIII-D Team

2011-07-01

The results of a large database of edge pedestal data from type-I ELMy H-mode discharges from ASDEX Upgrade and DIII-D are presented. The data from high resolution edge diagnostics of both devices is analysed with the same analysis code in order to avoid systematic differences. Furthermore, sophisticated equilibrium reconstructions are used to asses uncertainties which arise during mapping from 2D real space coordinates to 1D flux coordinates. ELM synchronization allows the study of the pedestal structure at the ELM stability boundary. The pedestal is characterized by its top value, the gradient and the width. A large parameter range is covered by the two devices. Over this parameter range the profile shape of edge electron density differs from that of the temperature, irrespective of the device. However, the resulting electron pressure profile shape remains similar for all analysed H-Mode discharges.
SEM-analysis of grain boundary porosity in three S-176 specimens

International Nuclear Information System (INIS)

Malen, K.; Birath, S.; Mattsson, O.

1980-10-01

Porosity in UO 2 -fuel has been studied in scanning electron microscope (SEM). The aim was to obtain a basis for evaluation of porosity in high burnup power reactor fuel. Three specimens have been analyzed. In the high temperature zones porosity can be seen both on grain boundaries and at grain edges. In the low temperature regions very little changes seem to have occurred during irradiation. (author)
Edge effect on post-dispersal artificial seed predation in the southeastern Amazonia, Brazil.

Science.gov (United States)

Penido, G; Ribeiro, V; Fortunato, D S

2015-05-01

This paper evaluates the post-dispersal artificial seed predation rates in two areas of the southeastern Amazon forest-savanna boundary, central Brazil. We conducted the survey in a disturbance regime controlled research site to verify if exists an edge effect in these rates and if the disturbance (in this case annual fire and no fire) affects seed predation. We placed 800 peanuts seeds in each area at regular distance intervals from the fragment`s edge. Data were analyzed by a likelihood ratio model selection in generalized linear models (GLM). The complete model (with effects from edge distance and site and its interaction) was significative (F3=4.43; p=0.005). Seeds had a larger predation rates in fragment's interior in both areas, but in the controlled area (no disturbance) this effect was less linear. This suggests an edge effect for post-dispersal seed predation, and that disturbances might alter these effects. Even if we exclude the site effect (grouping both areas together) there is still a strong edge effect on seed predation rates (F3=32.679; p>0.001). We did not verify predator's species in this study; however, the presence of several species of ants was extremely common in the seeds. The detection of an edge effect in only a short survey time suggests that there is heterogeneity in predation rates and that this variation might affect plant recruitment in fragmented areas of the Amazon forest. Henceforth, this seed predation should be taken in consideration in reforestation projects, where the main source of plants species is from seed distribution.

Study of Baffle Boundary and System Parameters on Liquid-Solid Coupling Vibration of Rectangular Liquid-Storage Structure

Directory of Open Access Journals (Sweden)

Wei Jing

2016-01-01

Full Text Available In order to study the vibration problem of liquid-solid coupling of rectangular liquid-storage structure with horizontal elastic baffle, ignoring the influence of surface gravity wave, two different velocity potential functions corresponding to the liquid above and below the elastic baffle are assumed; based on the theory of mathematical equation and energy method, the formulas of basic frequency of liquid-solid coupling vibration system are derived, the baffle joined to the tank wall with 3 kinds of boundary conditions, namely, four edges simply supported, two opposite edges clamped and two opposite edges simply supported, and four edges clamped; the influence rules of baffle length-width ratio, the ratio of baffle height to liquid level, baffle elastic modulus, baffle density, baffle thickness, and liquid density on the coupling vibration performance are studied. The results show that the frequency of the clamped boundary is minimum; the influences of baffle length-width ratio and relative height on the basic frequency are much greater than that of the other system parameters; the relation between baffle length-width ratio and the frequency is exponential, while baffle relative height has a parabola relation with the frequency; the larger the baffle length-width ratio, the closer the baffle to the liquid level; the coupling frequency will be reduced more obviously.
Modelization of a large wind farm, considering the modification of the atmospheric boundary layer

Energy Technology Data Exchange (ETDEWEB)

Crespo, A; Gomez-Elvira, R [Univ. Politecnica de Madrid, Mecanica de Fluidos, E.T.S.I. Industriales, Madrid (Spain); Frandsen, S; Larsen, S E [Risoe National Lab., Roskilde (Denmark)

1999-03-01

A method is presented to adapt existing models of wind farms to very large ones that may affect the whole planetary boundary layer. An internal boundary layer is considered that starts developing at the leading edge of the farm until it reaches, sufficiently far downstream, the top of the planetary boundary layer, and a new equilibrium region is reached. The wind farm is simulated by an artificial roughness that is function of the turbine spacing, drag and height. From this model the flow conditions are calculated at a certain reference height and then are used as boundary conditions for a numerical code used to model a wind farm. Three-dimensional effects are considered by applying appropriate conditions at the sides of the farm. Calculations are carried out to estimate the energy production in large wind farms, and it is found that additional losses due to modification of the planetary boundary layer may be of importance for wind farms of size larger than about 100 km. (au)
An experimental study of three-dimensional shock wave/boundary layer interactions generated by sharp fins

Science.gov (United States)

Lu, F. K.; Settles, G. S.; Bogdonoff, S. M.

1983-01-01

The interaction between a turbulent boundary layer and a shock wave generated by a sharp fin with leading edge sweepback was investigated. The incoming flow was at Mach 2.96 and at a unit Reynolds number of 63 x 10 to the 6th power 0.1 m. The approximate incoming boundary layer thickness was either 4 mm or 17 mm. The fins used were at 5 deg, 9 deg and 15 deg incidence and had leading edge sweepback from 0 deg to 65 deg. The tests consisted of surface kerosene lampblack streak visualization, surface pressure measurements, shock wave shape determination by shadowgraphs, and localized vapor screen visualization. The upstream influence lengths of the fin interactions were correlated using viscous and inviscid flow parameters. The parameters affecting the surface features close to the fin and way from the fin were also identified. Essentially, the surface features in the farfield were found to be conical.
Extraction and analysis of left ventricular contours in cardiac radionuclide angiographies

International Nuclear Information System (INIS)

Jouan, A.

1991-01-01

The analysis of cardiac scintigraphic sequences is commonly realized with the help of functional or parametric images. The decomposition of the original sequence into a linear combination of the main temporal behaviors yields, after orthogonalization, a set of parametric images representing the pure temporal behaviors present in the original data. The properties of these images are used to extract automatically the left ventricular boundary. The Fourier Descriptors method is then used to get a quantified analysis of the shape of the ventricle. Because of their property of invariance by change of scale, the Fourier descriptors method applied on a sequence of left ventricular contours yields a quantified assessment of the cardiac contraction
Turbulence and intermittent transport at the boundary of magnetized plasmas

DEFF Research Database (Denmark)

Garcia, O.E.; Naulin, V.; Nielsen, A.H.

2005-01-01

Numerical fluid simulations of interchange turbulence for geometry and parameters relevant to the boundary region of magnetically confined plasmas are shown to result in intermittent transport qualitatively similar to recent experimental measurements. The two-dimensional simulation domain features...... a forcing region with spatially localized sources of particles and heat outside which losses due to the motion along open magnetic-field lines dominate, corresponding to the edge region and the scrape-off layer, respectively. Turbulent states reveal intermittent eruptions of hot plasma from the edge region...... fluctuation wave forms and transport statistics are also in a good agreement with those derived from the experiments. Associated with the turbulence bursts are relaxation oscillations in the particle and heat confinements as well as in the kinetic energy of the sheared poloidal flows. The formation of blob...
Elastically Deformable Side-Edge Link for Trailing-Edge Flap Aeroacoustic Noise Reduction

Science.gov (United States)

Khorrami, Mehdi R. (Inventor); Lockard, David P. (Inventor); Moore, James B. (Inventor); Su, Ji (Inventor); Turner, Travis L. (Inventor); Lin, John C. (Inventor); Taminger, Karen M. (Inventor); Kahng, Seun K. (Inventor); Verden, Scott A. (Inventor)

2014-01-01

A system is provided for reducing aeroacoustic noise generated by an aircraft having wings equipped with trailing-edge flaps. The system includes a plurality of elastically deformable structures. Each structure is coupled to and along one of the side edges of one of the trailing-edge flaps, and is coupled to a portion of one of the wings that is adjacent to the one of the side edges. The structures elastically deform when the trailing-edge flaps are deployed away from the wings.
Localized Edge Vibrations and Edge Reconstruction by Joule Heating in Graphene Nanostructures

DEFF Research Database (Denmark)

Engelund, Mads; Fürst, Joachim Alexander; Jauho, Antti-Pekka

2010-01-01

Control of the edge topology of graphene nanostructures is critical to graphene-based electronics. A means of producing atomically smooth zigzag edges using electronic current has recently been demonstrated in experiments [Jia et al., Science 323, 1701 (2009)]. We develop a microscopic theory...... for current-induced edge reconstruction using density functional theory. Our calculations provide evidence for localized vibrations at edge interfaces involving unpassivated armchair edges. We demonstrate that these vibrations couple to the current, estimate their excitation by Joule heating, and argue...
Edge Probability and Pixel Relativity-Based Speckle Reducing Anisotropic Diffusion.

Science.gov (United States)

Mishra, Deepak; Chaudhury, Santanu; Sarkar, Mukul; Soin, Arvinder Singh; Sharma, Vivek

2018-02-01

Anisotropic diffusion filters are one of the best choices for speckle reduction in the ultrasound images. These filters control the diffusion flux flow using local image statistics and provide the desired speckle suppression. However, inefficient use of edge characteristics results in either oversmooth image or an image containing misinterpreted spurious edges. As a result, the diagnostic quality of the images becomes a concern. To alleviate such problems, a novel anisotropic diffusion-based speckle reducing filter is proposed in this paper. A probability density function of the edges along with pixel relativity information is used to control the diffusion flux flow. The probability density function helps in removing the spurious edges and the pixel relativity reduces the oversmoothing effects. Furthermore, the filtering is performed in superpixel domain to reduce the execution time, wherein a minimum of 15% of the total number of image pixels can be used. For performance evaluation, 31 frames of three synthetic images and 40 real ultrasound images are used. In most of the experiments, the proposed filter shows a better performance as compared to the state-of-the-art filters in terms of the speckle region's signal-to-noise ratio and mean square error. It also shows a comparative performance for figure of merit and structural similarity measure index. Furthermore, in the subjective evaluation, performed by the expert radiologists, the proposed filter's outputs are preferred for the improved contrast and sharpness of the object boundaries. Hence, the proposed filtering framework is suitable to reduce the unwanted speckle and improve the quality of the ultrasound images.
An evaluation of edge effects in nutritional accessibility and availability measures: a simulation study

Directory of Open Access Journals (Sweden)

Porter Dwayne E

2010-07-01

Full Text Available Abstract Background This paper addresses the statistical use of accessibility and availability indices and the effect of study boundaries on these measures. The measures are evaluated via an extensive simulation based on cluster models for local outlet density. We define outlet to mean either food retail store (convenience store, supermarket, gas station or restaurant (limited service or full service restaurants. We designed a simulation whereby a cluster outlet model is assumed in a large study window and an internal subset of that window is constructed. We performed simulations on various criteria including one scenario representing an urban area with 2000 outlets as well as a non-urban area simulated with only 300 outlets. A comparison is made between estimates obtained with the full study area and estimates using only the subset area. This allows the study of the effect of edge censoring on accessibility measures. Results The results suggest that considerable bias is found at the edges of study regions in particular for accessibility measures. Edge effects are smaller for availability measures (when not smoothed and also for short range accessibility Conclusions It is recommended that any study utilizing these measures should correct for edge effects. The use of edge correction via guard areas is recommended and the avoidance of large range distance-based accessibility measures is also proposed.
Boundary-Layer Characteristics of Persistent Regional Haze Events and Heavy Haze Days in Eastern China

Directory of Open Access Journals (Sweden)

Peng Huaqing

2016-01-01

Full Text Available This paper analyzed the surface conditions and boundary-layer climate of regional haze events and heavy haze in southern Jiangsu Province in China. There are 5 types with the surface conditions which are equalized pressure (EQP, the advancing edge of a cold front (ACF, the base of high pressure (BOH, the backside of high pressure (BAH, the inverted trough of low pressure (INT, and saddle pressure (SAP with the haze days. At that time, 4 types are divided with the regional haze events and each of which has a different boundary-layer structure. During heavy haze, the surface mainly experiences EQP, ACF, BOH, BAH, and INT which also have different boundary-layer structures.
Fully automated left ventricular contour detection for gated radionuclide angiography, (1)

International Nuclear Information System (INIS)

Hosoba, Minoru; Wani, Hidenobu; Hiroe, Michiaki; Kusakabe, Kiyoko.

1984-01-01

A fully automated practical method has been developed to detect the left ventricular (LV) contour from gated pool images. Ejection fraction and volume curve can be computed accurately without operater variance. The characteristics of the method are summarized as follows: 1. Optimal design of the filter that works on Fourier domain, can be achieved to improve the signal to noise ratio. 2. New algorithm which use the cosine and sine transform images has been developed for the separating ventricle from atrium and defining center of LV. 3. Contrast enhancement by optimized square filter. 4. Radial profiles are generated from the center of LV and smoothed by fourth order Fourier series approximation. The crossing point with local threshold value searched from the center of the LV is defined as edge. 5. LV contour is obtained by conecting all the edge points defined on radial profiles by fitting them to Fourier function. (author)
Edge effects enhance selfing and seed harvesting efforts in the insect-pollinated Neotropical tree Copaifera langsdorffii (Fabaceae).

Science.gov (United States)

Tarazi, R; Sebbenn, A M; Kageyama, P Y; Vencovsky, R

2013-06-01

Edge effects may affect the mating system of tropical tree species and reduce the genetic diversity and variance effective size of collected seeds at the boundaries of forest fragments because of a reduction in the density of reproductive trees, neighbour size and changes in the behaviour of pollinators. Here, edge effects on the genetic diversity, mating system and pollen pool of the insect-pollinated Neotropical tree Copaifera langsdorffii were investigated using eight microsatellite loci. Open-pollinated seeds were collected from 17 seed trees within continuous savannah woodland (SW) and were compared with seeds from 11 seed trees at the edge of the savannah remnant. Seeds collected from the SW had significantly higher heterozygosity levels (Ho=0.780; He=0.831) than seeds from the edge (Ho=0.702; He=0.800). The multilocus outcrossing rate was significantly higher in the SW (tm=0.859) than in the edge (tm=0.759). Pollen pool differentiation was significant, however, it did not differ between the SW (=0.105) and the edge (=0.135). The variance effective size within the progenies was significantly higher in the SW (Ne=2.65) than at the edge (Ne=2.30). The number of seed trees to retain the reference variance effective size of 500 was 189 at the SW and 217 at the edge. Therefore, it is preferable that seed harvesting for conservation and environmental restoration strategies be conducted in the SW, where genetic diversity and variance effective size within progenies are higher.
Perceptions of boundary ambiguity in the process of leaving an abusive partner.

Science.gov (United States)

Khaw, Lyndal; Hardesty, Jennifer L

2015-06-01

The process of leaving an abusive partner has been theorized using the Stages of Change Model. Although useful, this model does not account for changes in relational boundaries unique to the process of leaving. Using family stress and feminist perspectives, this study sought to integrate boundary ambiguity into the Stages of Change Model. Boundary ambiguity is defined as a perception of uncertainty as to who is in or out of a family system (Boss & Greenberg, 1984). Twenty-five mothers who had temporarily or permanently left their abusers were interviewed. Data were analyzed using constructivist grounded theory methods. Results identify types, indicators of, and mothers' responses to boundary ambiguity throughout the five stages of change. Most mothers and abusers fluctuated between physical and psychological presence and absence over multiple separations. The integration of boundary ambiguity into the Stages of Change Model highlights the process of leaving an abusive partner as systemic, fluid, and nonlinear. © 2014 Family Process Institute.
Nonreciprocity of edge modes in 1D magnonic crystal

International Nuclear Information System (INIS)

Lisenkov, I.; Kalyabin, D.; Osokin, S.; Klos, J.W.; Krawczyk, M.; Nikitov, S.

2015-01-01

Spin waves propagation in 1D magnonic crystals is investigated theoretically. Mathematical model based on plane wave expansion method is applied to different types of magnonic crystals, namely bi-component magnonic crystal with symmetric/asymmetric boundaries and ferromagnetic film with periodically corrugated top surface. It is shown that edge modes in magnonic crystals may exhibit nonreciprocal behaviour at much lower frequencies than in homogeneous films. - Highlights: • Magnetostatic surface spin waves in 1D magnonic crystals were studied theoretically. • Mathematical model is based on plane wave method. • Mathematical model was applied to different types of magnonic crystals. • Stop band formation and nonreciprocity were obtained
Grammars Leak: Modeling How Phonotactic Generalizations Interact within the Grammar

Science.gov (United States)

Martin, Andrew

2011-01-01

I present evidence from Navajo and English that weaker, gradient versions of morpheme-internal phonotactic constraints, such as the ban on geminate consonants in English, hold even across prosodic word boundaries. I argue that these lexical biases are the result of a MAXIMUM ENTROPY phonotactic learning algorithm that maximizes the probability of…
Edge printability: techniques used to evaluate and improve extreme wafer edge printability

Science.gov (United States)

Roberts, Bill; Demmert, Cort; Jekauc, Igor; Tiffany, Jason P.

2004-05-01

The economics of semiconductor manufacturing have forced process engineers to develop techniques to increase wafer yield. Improvements in process controls and uniformities in all areas of the fab have reduced film thickness variations at the very edge of the wafer surface. This improved uniformity has provided the opportunity to consider decreasing edge exclusions, and now the outermost extents of the wafer must be considered in the yield model and expectations. These changes have increased the requirements on lithography to improve wafer edge printability in areas that previously were not even coated. This has taxed all software and hardware components used in defining the optical focal plane at the wafer edge. We have explored techniques to determine the capabilities of extreme wafer edge printability and the components of the systems that influence this printability. We will present current capabilities and new detection techniques and the influence that the individual hardware and software components have on edge printability. We will show effects of focus sensor designs, wafer layout, utilization of dummy edge fields, the use of non-zero overlay targets and chemical/optical edge bead optimization.
Asymptotic analysis of a pile-up of regular edge dislocation walls

KAUST Repository

Hall, Cameron L.

2011-12-01

The idealised problem of a pile-up of regular dislocation walls (that is, of planes each containing an infinite number of parallel, identical and equally spaced dislocations) was presented by Roy et al. [A. Roy, R.H.J. Peerlings, M.G.D. Geers, Y. Kasyanyuk, Materials Science and Engineering A 486 (2008) 653-661] as a prototype for understanding the importance of discrete dislocation interactions in dislocation-based plasticity models. They noted that analytic solutions for the dislocation wall density are available for a pile-up of regular screw dislocation walls, but that numerical methods seem to be necessary for investigating regular edge dislocation walls. In this paper, we use the techniques of discrete-to-continuum asymptotic analysis to obtain a detailed description of a pile-up of regular edge dislocation walls. To leading order, we find that the dislocation wall density is governed by a simple differential equation and that boundary layers are present at both ends of the pile-up. © 2011 Elsevier B.V.
Asymptotic analysis of a pile-up of regular edge dislocation walls

KAUST Repository

Hall, Cameron L.

2011-01-01

The idealised problem of a pile-up of regular dislocation walls (that is, of planes each containing an infinite number of parallel, identical and equally spaced dislocations) was presented by Roy et al. [A. Roy, R.H.J. Peerlings, M.G.D. Geers, Y. Kasyanyuk, Materials Science and Engineering A 486 (2008) 653-661] as a prototype for understanding the importance of discrete dislocation interactions in dislocation-based plasticity models. They noted that analytic solutions for the dislocation wall density are available for a pile-up of regular screw dislocation walls, but that numerical methods seem to be necessary for investigating regular edge dislocation walls. In this paper, we use the techniques of discrete-to-continuum asymptotic analysis to obtain a detailed description of a pile-up of regular edge dislocation walls. To leading order, we find that the dislocation wall density is governed by a simple differential equation and that boundary layers are present at both ends of the pile-up. © 2011 Elsevier B.V.
Mixed convection boundary layer flow over a vertical surface embedded in a thermally stratified porous medium

International Nuclear Information System (INIS)

Ishak, Anuar; Nazar, Roslinda; Pop, Ioan

2008-01-01

The mixed convection boundary layer flow through a stable stratified porous medium bounded by a vertical surface is investigated. The external velocity and the surface temperature are assumed to vary as x m , where x is measured from the leading edge of the vertical surface and m is a constant. Numerical solutions for the governing Darcy and energy equations are obtained. The results indicate that the thermal stratification significantly affects the surface shear stress as well as the surface heat transfer, besides delays the boundary layer separation
Trip-Induced Transition Measurements in a Hypersonic Boundary Layer Using Molecular Tagging Velocimetry

Science.gov (United States)

Bathel, Brett F.; Danehy, Paul M.; Jones, Stephen B.; Johansen, Craig T.; Goyne, Christopher P.

2013-01-01

Measurements of mean streamwise velocity, fluctuating streamwise velocity, and instantaneous streamwise velocity profiles in a hypersonic boundary layer were obtained over a 10-degree half-angle wedge model. A laser-induced fluorescence-based molecular tagging velocimetry technique was used to make the measurements. The nominal edge Mach number was 4.2. Velocity profiles were measured both in an untripped boundary layer and in the wake of a 4-mm diameter cylindrical tripping element centered 75.4 mm downstream of the sharp leading edge. Three different trip heights were investigated: k = 0.53 mm, k = 1.0 mm and k = 2.0 mm. The laminar boundary layer thickness at the position of the measurements was approximately 1 mm, though the exact thickness was dependent on Reynolds number and wall temperature. All of the measurements were made starting from a streamwise location approximately 18 mm downstream of the tripping element. This measurement region continued approximately 30 mm in the streamwise direction. Additionally, measurements were made at several spanwise locations. An analysis of flow features show how the magnitude, spatial location, and spatial growth of streamwise velocity instabilities are affected by parameters such as the ratio of trip height to boundary layer thickness and roughness Reynolds number. The fluctuating component of streamwise velocity measured along the centerline of the model increased from approximately 75 m/s with no trip to +/-225 m/s with a 0.53-mm trip, and to +/-240 m/s with a 1-mm trip, while holding the freestream Reynolds number constant. These measurements were performed in the 31-inch Mach 10 Air Tunnel at the NASA Langley Research Center.

Edge effect on post-dispersal artificial seed predation in the southeastern Amazonia, Brazil

Directory of Open Access Journals (Sweden)

G. Penido

Full Text Available This paper evaluates the post-dispersal artificial seed predation rates in two areas of the southeastern Amazon forest-savanna boundary, central Brazil. We conducted the survey in a disturbance regime controlled research site to verify if exists an edge effect in these rates and if the disturbance (in this case annual fire and no fire affects seed predation. We placed 800 peanuts seeds in each area at regular distance intervals from the fragment`s edge. Data were analyzed by a likelihood ratio model selection in generalized linear models (GLM. The complete model (with effects from edge distance and site and its interaction was significative (F3=4.43; p=0.005. Seeds had a larger predation rates in fragment’s interior in both areas, but in the controlled area (no disturbance this effect was less linear. This suggests an edge effect for post-dispersal seed predation, and that disturbances might alter these effects. Even if we exclude the site effect (grouping both areas together there is still a strong edge effect on seed predation rates (F3=32.679; p>0.001. We did not verify predator’s species in this study; however, the presence of several species of ants was extremely common in the seeds. The detection of an edge effect in only a short survey time suggests that there is heterogeneity in predation rates and that this variation might affect plant recruitment in fragmented areas of the Amazon forest. Henceforth, this seed predation should be taken in consideration in reforestation projects, where the main source of plants species is from seed distribution.
Edge Matters

DEFF Research Database (Denmark)

Earon, Ofri

2013-01-01

of this container is to separate inside from outside and to protect and provide privacy, psychological as well as physical (Venturi, 1966). But, if dwelling phenomenon takes place both inside and outside the private house – why is the urban house an enclosed box? What is the differentiation between inside...... and outside the contemporary urban house? And what is the interplay between them? The research argues for re-thinking the edge zone between inside and outside the urban house. Therefore, although, residential buildings in the city are the objects of study, the focal point here is the edge zone along...... the building. The research explores and develops the architectural characteristics of correlations between the resident, the singular unit, the building and the given location at the edge zone. It approaches the edge zone of the urban house as a platform for dynamic interactions between these behaviours...
Dual-Use Transducer for Use with a Boundary-Stiffened Panel and Method of Using the Same

Science.gov (United States)

Schiller, Noah H. (Inventor); Cabell, Randolph H. (Inventor)

2011-01-01

A transducer for use with a boundary-stiffened panel has an inter-digitated electrode (IDE) and a piezoelectric wafer portion positioned therebetween. The IDE and/or the wafer portion are triangular, with one edge or side aligned with a boundary edge of the panel. The transducer generates and transmits an output force to the panel in response to an input voltage signal from a sensor, which can be another transducer as described above or an accelerometer. A controller can generate an output force signal in response to the input voltage signal to help cancel the input voltage signal. A method of using the transducer minimizes vibration in the panel by connecting multiple transducers around a perimeter thereof. Motion is measured at different portions of the panel, and a voltage signal determined from the motion is transmitted to the transducers to generate an output force at least partially cancelling or damping the motion.
Wall-attached structures of streamwise velocity fluctuations in turbulent boundary layer

Science.gov (United States)

Hwang, Jinyul; Sung, Hyung Jin

2017-11-01

The wall-attached structures of streamwise velocity fluctuations (u) are explored using direct numerical simulation data of turbulent boundary layer at Reτ = 1000 . We identify the structures of u, which are extended close to the wall. Their height (ly) ranges from the near-wall region to the edge of turbulent boundary layer. They are geometrically self-similar in a sense that the length and width of the structures are proportional to the distance from the wall. The population density of the attached structures shows that the tall attached structures (290 wall. The wall-attached structures of u identified in the present work are a proper candidate for Townsend's attached eddy hypothesis and these structures exist in the low Reynolds number turbulent boundary layer. This work was supported by the Creative Research Initiatives (No. 2017-013369) program of the National Research Foundation of Korea (MSIP) and supported by the Supercomputing Center (KISTI).
Receptivity of Hypersonic Boundary Layers to Acoustic and Vortical Disturbances (Invited)

Science.gov (United States)

Balakumar, P.

2015-01-01

Boundary-layer receptivity to two-dimensional acoustic and vortical disturbances for hypersonic flows over two-dimensional and axi-symmetric geometries were numerically investigated. The role of bluntness, wall cooling, and pressure gradients on the receptivity and stability were analyzed and compared with the sharp nose cases. It was found that for flows over sharp nose geometries in adiabatic wall conditions the instability waves are generated in the leading-edge region and that the boundary layer is much more receptive to slow acoustic waves as compared to the fast waves. The computations confirmed the stabilizing effect of nose bluntness and the role of the entropy layer in the delay of boundary layer transition. The receptivity coefficients in flows over blunt bodies are orders of magnitude smaller than that for the sharp cone cases. Wall cooling stabilizes the first mode strongly and destabilizes the second mode. However, the receptivity coefficients are also much smaller compared to the adiabatic case. The adverse pressure gradients increased the unstable second mode regions.
Impact of the plasma response in three-dimensional edge plasma transport modelling for RMP ELM control scenarios at ITER

Science.gov (United States)

Schmitz, Oliver

2014-10-01

The constrains used in magneto-hydrodynamic (MHD) modeling of the plasma response to external resonant magnetic perturbation (RMP) fields have a profound impact on the three-dimensional (3-D) shape of the plasma boundary induced by RMP fields. In this contribution, the consequences of the plasma response on the actual 3D boundary structure and transport during RMP application at ITER are investigated. The 3D fluid plasma and kinetic neutral transport code EMC3-Eirene is used for edge transport modeling. Plasma response modeling is conducted with the M3D-C1 code using a single fluid, non-linear and a two fluid, linear MHD constrain. These approaches are compared to results with an ideal MHD like plasma response. A 3D plasma boundary is formed for all cases consisting of magnetic finger structures at the X-point intersecting the divertor surface in a helical footprint pattern. The width of the helical footprint pattern is largely reduced compared to vacuum magnetic fields when using the ideal MHD like screening model. This yields increasing peak heat fluxes in contrast to a beneficial heat flux spreading seen with vacuum fields. The particle pump out as well as loss of thermal energy is reduced by a factor of two compared to vacuum fields. In contrast, the impact of the plasma response obtained from both MHD constrains in M3D-C1 is nearly negligible at the plasma boundary and only a small modification of the magnetic footprint topology is detected. Accordingly, heat and particle fluxes on the target plates as well as the edge transport characteristics are comparable to the vacuum solution. This span of modeling results with different plasma response models highlights the importance of thoroughly validating both, plasma response and 3D edge transport models for a robust extrapolation towards ITER. Supported by ITER Grant IO/CT/11/4300000497 and F4E Grant GRT-055 (PMS-PE) and by Start-Up Funds of the University of Wisconsin - Madison.
An edge pedestal model

International Nuclear Information System (INIS)

Stacev, W.M.

2001-01-01

A new model for calculation of the gradient scale lengths in the edge pedestal region and of the edge transport barrier width in H-mode tokamak plasmas will be described. Model problem calculations which demonstrate the promise of this model for predicting experimental pedestal properties will be discussed. The density and Prague gradient scale lengths (L) in the edge are calculated from the particle and ion and electron energy radial transport equations, making use of (presumed) known particle and energy fluxes flowing across the edge transport barrier from the core into the SOL and of edge transport coefficients. The average values of the particle and heat fluxes in the edge transport barrier are calculated in terms of the fluxes crossing into the SOL and the atomic physics reaction rates (ionisation, charge-exchange, elastic scattering, impurity radiation) in the edge by integrating the respective transport equations from the pedestal to the separatrix. An important implication of this model is that the pedestal gradient scale lengths depend not just on local pedestal platers properties but also on particle and energy fluxes from the core plasma and on recycling neutral fluxes that penetrate into the plasma edge, both of which in turn depend on the pedestal properties. The MHD edge pressure gradient constraint α≤ α C is used to determine the pressure width of the edge transport barrier, Δ TB = Δ TB (α c ). Three different models for the MHD edge pressure gradient constraint have been investigated: (1) nominal ideal ballooning mode theory, (2) ballooning mode theory taking into account the edge geometry and shear to access He second stability region; and pedestal β-limit theory when the ballooning modes are stabilised by diamagnetic effects. A series of calculations have been made for a DIII-D model problem. The calculated gradient scale lengths and edge transport barrier widths are of the magnitude of values observed experimentally, and certain trends
Internal and edge cracks in a plate of finite width under bending

Science.gov (United States)

Boduroglu, H.; Erdogan, F.

1983-01-01

In this paper the title problem is studied by using Reissner's transverse shear theory. The main purpose of the paper is to investigate the effect of stress-free boundaries on the stress intensity factors in plates under bending. Among the results found particularly interesting are those relating to the limiting cases of the crack geometries. The numerical results are given for a single internal crack, two collinear cracks, and two edge cracks. Also studied is the effect of Poisson's ratio on the stress intensity factors.
Effects of external boundary layer flow on jet noise in flight

Science.gov (United States)

Sarohia, V.; Massier, P. F.

1976-01-01

The effects on jet flow of the external boundary layer flow emanating from the trailing edge of an engine cowl in flight has been shown to be the main reason for the disparity between predicted and experimental results obtained from flight measurements. Flight simulation experiments indicate that the external boundary layer flow tends to shield the jet flow in flight. This in turn modifies the jet noise source in flight and consequently the radiated noise from aircraft in flight. Close to 90 deg angle to the intake and in the forward quadrant, this study indicates that the far field jet noise and its spectrum scales approximately with the absolute jet velocity instead of the relative velocity as has been assumed in the existing prediction models.
High Resolution Topography Analysis on Threading Edge Dislocations in 4H-SiC Epilayers

International Nuclear Information System (INIS)

Kamata, I.; Nagano, M.; Tsuchida, H.; Chen, Y.; Dudley, M.

2009-01-01

Threading edge dislocations (TEDs) in a 4H-SiC epitaxial layer are investigated using high-resolution synchrotron topography. Six types of TED image are confirmed to correspond to the Burgers vector directions by a comparison of computer simulated images and observed topography images in crystal boundaries. Using a mapping method, a wide spatial distribution of the six types of TED is examined in a quarter section of a 2-inch wafer.
Buckling and postbuckling of composite panels with cutouts subjected to combined edge shear and temperature change

Science.gov (United States)

Noor, Ahmed K.; Kim, Yong H.

1995-01-01

The results of a detailed study of the buckling and postbuckling responses of composite panels with central circular cutouts are presented. The panels are subjected to combined edge shear and temperature change. The panels are discretized by using a two-field degenerate solid element with each of the displacement components having a linear variation throughout the thickness of the panel. The fundamental unknowns consist of the average mechanical strains through the thickness and the displacement components. The effects of geometric nonlinearities and laminated anisotropic material behavior are included. The stability boundary, postbuckling response and the hierarchical sensitivity coefficients are evaluated. The hierarchical sensitivity coefficients measure the sensitivity of the buckling and postbuckling responses to variations in the panel stiffnesses, and the material properties of both the individual layers and the constituents (fibers and matrix). Numerical results are presented for composite panels with central circular cutouts subjected to combined edge shear and temperature change, showing the effects of variations in the hole diameter, laminate stacking sequence and fiber orientation, on the stability boundary and postbuckling response and their sensitivity to changes in the various panel parameters.
Non-compact left ventricle/hypertrabeculated left ventricle

International Nuclear Information System (INIS)

Restrepo, Gustavo; Castano, Rafael; Marmol, Alejandro

2005-01-01

Non-compact left ventricle/hypertrabeculated left ventricle is a myocardiopatie produced by an arrest of the normal left ventricular compaction process during the early embryogenesis. It is associated to cardiac anomalies (congenital cardiopaties) as well as to extracardial conditions (neurological, facial, hematologic, cutaneous, skeletal and endocrinological anomalies). This entity is frequently unnoticed, being diagnosed only in centers with great experience in the diagnosis and treatment of myocardiopathies. Many cases of non-compact left ventricle have been initially misdiagnosed as hypertrophic myocardiopatie, endocardial fibroelastosis, dilated cardiomyopatie, restrictive cardiomyopathy and endocardial fibrosis. It is reported the case of a 74 years old man with a history of chronic arterial hypertension and diabetes mellitus, prechordial chest pain and mild dyspnoea. An echocardiogram showed signs of non-compact left ventricle with prominent trabeculations and deep inter-trabecular recesses involving left ventricular apical segment and extending to the lateral and inferior walls. Literature on this topic is reviewed
Talk this way: the effect of prosodically conveyed semantic information on memory for novel words.

Science.gov (United States)

Shintel, Hadas; Anderson, Nathan L; Fenn, Kimberly M

2014-08-01

Speakers modulate their prosody to express not only emotional information but also semantic information (e.g., raising pitch for upward motion). Moreover, this information can help listeners infer meaning. Work investigating the communicative role of prosodically conveyed meaning has focused on reference resolution, and potential mnemonic benefits remain unexplored. We investigated the effect of prosody on memory for the meaning of novel words, even when it conveys superfluous information. Participants heard novel words, produced with congruent or incongruent prosody, and viewed image pairs representing the intended meaning and its antonym (e.g., a small and a large dog). Importantly, an arrow indicated the image representing the intended meaning, resolving the ambiguity. Participants then completed 2 memory tests, either immediately after learning or after a 24-hr delay, on which they chose an image (out of a new image pair) and a definition that best represented the word. On the image test, memory was similar on the immediate test, but incongruent prosody led to greater loss over time. On the definition test, memory was better for congruent prosody at both times. Results suggest that listeners extract semantic information from prosody even when it is redundant and that prosody can enhance memory, beyond its role in comprehension. PsycINFO Database Record (c) 2014 APA, all rights reserved.
Iridium Coating Deposited by Double Glow Plasma Technique — Effect of Glow Plasma on Structure of Coating at Single Substrate Edge

International Nuclear Information System (INIS)

Wu Wangping; Chen Zhaofeng; Liu Yong

2012-01-01

Double glow plasma technique has a high deposition rate for preparing iridium coating. However, the glow plasma can influence the structure of the coating at the single substrate edge. In this study, the iridium coating was prepared by double glow plasma on the surface of single niobium substrate. The microstructure of iridium coating at the substrate edge was observed by scanning electron microscopy. The composition of the coating was confirmed by energy dispersive spectroscopy and X-ray diffraction. There was a boundary between the coating and the substrate edge. The covered area for the iridium coating at the substrate edge became fewer and fewer from the inner area to the outer flange-area. The bamboo sprout-like particles on the surface of the substrate edge were composed of elemental niobium. The substrate edge was composed of the Nb coating and there was a transition zone between the Ir coating and the Nb coating. The interesting phenomenon of the substrate edge could be attributed to the effects of the bias voltages and the plasma cloud in the deposition chamber. The substrate edge effect could be mitigated or eliminated by adding lots of small niobium plates around the substrate in a deposition process. (plasma technology)
Uniform surface-to-line integral reduction of physical optics for curved surfaces by modified edge representation with higher-order correction

Science.gov (United States)

Lyu, Pengfei; Ando, Makoto

2017-09-01

The modified edge representation is one of the equivalent edge currents approximation methods for calculating the physical optics surface radiation integrals in diffraction analysis. The Stokes' theorem is used in the derivation of the modified edge representation from the physical optics for the planar scatterer case, which implies that the surface integral is rigorously reduced into the line integral of the modified edge representation equivalent edge currents, defined in terms of the local shape of the edge. On the contrary, for curved surfaces, the results of radiation integrals depend upon the global shape of the scatterer. The physical optics surface integral consists of two components, from the inner stationary phase point and the edge. The modified edge representation is defined independently from the orientation of the actual edge, and therefore, it could be available not only at the edge but also at the arbitrary points on the scatterer except the stationary phase point where the modified edge representation equivalent edge currents becomes infinite. If stationary phase point exists inside the illuminated region, the physical optics surface integration is reduced into two kinds of the modified edge representation line integrations, along the edge and infinitesimally small integration around the inner stationary phase point, the former and the latter give the diffraction and reflection components, respectively. The accuracy of the latter has been discussed for the curved surfaces and published. This paper focuses on the errors of the former and discusses its correction. It has been numerically observed that the modified edge representation works well for the physical optics diffraction in flat and concave surfaces; errors appear especially for the observer near the reflection shadow boundary if the frequency is low for the convex scatterer. This paper gives the explicit expression of the higher-order correction for the modified edge representation.
Tangential 2-D Edge Imaging for GPI and Edge/Impurity Modeling

International Nuclear Information System (INIS)

Maqueda, Ricardo; Levinton, Fred M.

2011-01-01

Nova Photonics, Inc. has a collaborative effort at the National Spherical Torus Experiment (NSTX). This collaboration, based on fast imaging of visible phenomena, has provided key insights on edge turbulence, intermittency, and edge phenomena such as edge localized modes (ELMs) and multi-faceted axisymmetric radiation from the edge (MARFE). Studies have been performed in all these areas. The edge turbulence/intermittency studies make use of the Gas Puff Imaging diagnostic developed by the Principal Investigator (Ricardo Maqueda) together with colleagues from PPPL. This effort is part of the International Tokamak Physics Activity (ITPA) edge, scrape-off layer and divertor group joint activity (DSOL-15: Inter-machine comparison of blob characteristics). The edge turbulence/blob study has been extended from the current location near the midplane of the device to the lower divertor region of NSTX. The goal of this effort was to study turbulence born blobs in the vicinity of the X-point region and their circuit closure on divertor sheaths or high density regions in the divertor. In the area of ELMs and MARFEs we have studied and characterized the mode structure and evolution of the ELM types observed in NSTX, as well as the study of the observed interaction between MARFEs and ELMs. This interaction could have substantial implications for future devices where radiative divertor regions are required to maintain detachment from the divertor plasma facing components.
Modelling of boundary plasma in TOKES

International Nuclear Information System (INIS)

Igitkhanov, Yu.; Pestchanyi, S.; Landman, I.

2009-12-01

. The model based on power scaling for L to H transition and includes the mitigation of turbulence at the edge once the flowing power exceeds the H-mode onset threshold. - The model of the Edge Localized Mode oscillation based on ballooning mode instability is implemented into code. - The boundary conditions for fluid equations at the divertor plates and at the main chamber wall are formulated and implemented into the integrated code. - Analyses of available experiments and benchmarking with simple analytical solutions in respect to SOL transport phenomena have been provided. Application for ITER is described. (orig.)
Boundary layer on a flat plate with suction

International Nuclear Information System (INIS)

Favre, A.; Dumas, R.; Verollet, E.

1961-01-01

This research done in wind tunnel concerns the turbulent boundary layer of a porous flat plate with suction. The porous wall is 1 m long and begins 1 m downstream of the leading edge. The Reynolds number based on the boundary layer thickness is of the order of 16.300. The suction rate defined as the ratio of the velocity perpendicular to the wall to the external flow velocity ranges from 0 to 2 per cent. The pressure gradient can be controlled. The mean velocity profiles have been determined for various positions and suction rates by means of total pressure probes together with the intensities of the turbulent velocity fluctuations components, energy spectra and correlations by means of hot wire anemometers, spectral analyser and correlator. The stream lines, the values of the viscous and turbulent shear stresses, of the local wall friction, of the turbulent energy production term, with some information on the dissipation of the energy have been derived from these measurements. For these data the integral of equation of continuity in boundary layer have been drawn. The suction effects on the boundary layer are important. The suction thoroughly alters the mean velocity profiles by increasing the viscous shear stresses near the wall and decreasing them far from the wall, it diminishes the longitudinal and transversal turbulence intensities, the turbulent shear stresses, and the production of energy of turbulence. These effects are much stressed in the inner part of the boundary layer. On the other hand the energy spectra show that the turbulence scale is little modified, the boundary layer thickness being not much diminished by the suction. The suction effects can be appreciated by comparing twice the suction rate to the wall friction coefficient (assumed airtight), quite noticeable as soon as the rate is about unity, they become very important when it reaches ten. (author) [fr
Plasma boundary experiments on DIII-D tokamak

International Nuclear Information System (INIS)

Mahdavi, M.A.; Brooks, N.; Jackson, G.L.; Langhorn, A.; Leikind, B.; Lippmann, S.; Luxon, J.; Petersen, P.; Petrie, P.; Stambaugh, R.D.; Simonen, T.C.; Staebler, G.; Buchenauer, D.; Futch, A.; Hill, D.N.; Rensink, M.; Hogan, J.; Menon, M.; Mioduszewski, P.K.; Owen, L.; Matthews, G.

1990-01-01

A survey of the boundary physics research on the DIII-D tokamak and an outline of the DIII-D Advanced Divertor Program (ADP) is presented. We will present results of experiments on impurity control, impurity transport, neutral particle transport, and particle effects on core confinement over a wide range of plasma parameters, I p T < or approx.10.7%, P(auxiliary)< or approx.20 MW. Based on the understanding gained in these studies, we in collaboration with a number of other laboratories have devised a series of experiments (ADP) to modify the core plasma conditions through changes in the edge electric field, neutral recycling, and plasma-surface interactions. (orig.)
RANS Based Methodology for Predicting the Influence of Leading Edge Erosion on Airfoil Performance

Energy Technology Data Exchange (ETDEWEB)

Langel, Christopher M. [Univ. of California, Davis, CA (United States). Dept. of Mechanical and Aerospace Engineering; Chow, Raymond C. [Univ. of California, Davis, CA (United States). Dept. of Mechanical and Aerospace Engineering; van Dam, C. P. [Univ. of California, Davis, CA (United States). Dept. of Mechanical and Aerospace Engineering; Maniaci, David Charles [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Wind Energy Technologies Dept.

2017-10-01

The impact of surface roughness on flows over aerodynamically designed surfaces is of interested in a number of different fields. It has long been known the surface roughness will likely accelerate the laminar- turbulent transition process by creating additional disturbances in the boundary layer. However, there are very few tools available to predict the effects surface roughness will have on boundary layer flow. There are numerous implications of the premature appearance of a turbulent boundary layer. Increases in local skin friction, boundary layer thickness, and turbulent mixing can impact global flow properties compounding the effects of surface roughness. With this motivation, an investigation into the effects of surface roughness on boundary layer transition has been conducted. The effort involved both an extensive experimental campaign, and the development of a high fidelity roughness model implemented in a R ANS solver. Vast a mounts of experimental data was generated at the Texas A&M Oran W. Nicks Low Speed Wind Tunnel for the calibration and validation of the roughness model described in this work, as well as future efforts. The present work focuses on the development of the computational model including a description of the calibration process. The primary methodology presented introduces a scalar field variable and associated transport equation that interacts with a correlation based transition model. The additional equation allows for non-local effects of surface roughness to be accounted for downstream of rough wall sections while maintaining a "local" formulation. The scalar field is determined through a boundary condition function that has been calibrated to flat plate cases with sand grain roughness. The model was initially tested on a NACA 0012 airfoil with roughness strips applied to the leading edge. Further calibration of the roughness model was performed using results from the companion experimental study on a NACA 63₃ -418 airfoil

A Novel Edge-Map Creation Approach for Highly Accurate Pupil Localization in Unconstrained Infrared Iris Images

Directory of Open Access Journals (Sweden)

Vineet Kumar

2016-01-01

Full Text Available Iris segmentation in the iris recognition systems is a challenging task under noncooperative environments. The iris segmentation is a process of detecting the pupil, iris’s outer boundary, and eyelids in the iris image. In this paper, we propose a pupil localization method for locating the pupils in the non-close-up and frontal-view iris images that are captured under near-infrared (NIR illuminations and contain the noise, such as specular and lighting reflection spots, eyeglasses, nonuniform illumination, low contrast, and occlusions by the eyelids, eyelashes, and eyebrow hair. In the proposed method, first, a novel edge-map is created from the iris image, which is based on combining the conventional thresholding and edge detection based segmentation techniques, and then, the general circular Hough transform (CHT is used to find the pupil circle parameters in the edge-map. Our main contribution in this research is a novel edge-map creation technique, which reduces the false edges drastically in the edge-map of the iris image and makes the pupil localization in the noisy NIR images more accurate, fast, robust, and simple. The proposed method was tested with three iris databases: CASIA-Iris-Thousand (version 4.0, CASIA-Iris-Lamp (version 3.0, and MMU (version 2.0. The average accuracy of the proposed method is 99.72% and average time cost per image is 0.727 sec.
Left regular bands of groups of left quotients

International Nuclear Information System (INIS)

El-Qallali, A.

1988-10-01

A semigroup S which has a left regular band of groups as a semigroup of left quotients is shown to be the semigroup which is a left regular band of right reversible cancellative semigroups. An alternative characterization is provided by using spinned products. These results are applied to the case where S is a superabundant whose set of idempotents forms a left normal band. (author). 13 refs
Forests on the edge: Microenvironmental drivers of carbon cycle response to edge effects

Science.gov (United States)

Reinmann, A.; Hutyra, L.; Smith, I. A.; Thompson, J.

2017-12-01

Twenty percent of the world's forest is within 100 m of a forest edge, but much of our understanding of forest carbon (C) cycling comes from large, intact ecosystems, which creates an important mismatch between the landscapes we study and those we aim to characterize. The temperate broadleaf forest is the most heavily fragmented forest biome in the world and its growth and carbon storage responses to forest edge effects appear to be the opposite of those in the tropical and boreal regions. We used field measurements to quantify the drivers of temperate forest C cycling response to edge effects, characterizing vegetative growth, respiration, and forest structure. We find large gradients in air and soil temperature from the forest interior to edge (up to 4 and 10° C, respectively) and the magnitude of this gradient is inversely correlated to the size of the forest edge growth enhancement. Further, leaf area index increases with proximity to the forest edge. While we also find increases in soil respiration between the forest interior and edge, this flux is small relative to aboveground growth enhancement near the edge. These findings represent an important advancement in our understanding of forest C cycle response to edge effects and will greatly improve our capacity to constrain biogenic C fluxes in fragmented and heterogeneous landscapes.
Edge modulation of electronics and transport properties of cliff-edge phosphorene nanoribbons

Science.gov (United States)

Guo, Caixia; Wang, Tianxing; Xia, Congxin; Liu, Yufang

2017-12-01

Based on the first-principles calculations, we study the electronic structures and transport properties of cliff-like edge phosphorene nanoribbons (CPNRs), considering different types of edge passivation. The band structures of bare CPNRs possess the metallic features; while hydrogen (H), fluorine (F), chlorine (Cl) and oxygen (O) atoms-passivated CPNRs are semiconductor materials, and the band gap values monotonically decrease when the ribbon width increases. Moreover, the H and F-passivated CPNRs exhibit the direct band gap characteristics, while the Cl and O-passivated cases show the features of indirect band gap. In addition, the edge passivated CPNRs are more energetically stable than bare edge case. Meanwhile, our results also show that the transport properties of the CPNRs can be obviously influenced by the different edge passivation.
Wild pigs (Sus scrofa) mediate large-scale edge effects in a lowland tropical rainforest in Peninsular Malaysia.

Science.gov (United States)

Fujinuma, Junichi; Harrison, Rhett D

2012-01-01

Edge-effects greatly extend the area of tropical forests degraded through human activities. At Pasoh, Peninsular Malaysia, it has been suggested that soil disturbance by highly abundant wild pigs (Sus scrofa), which feed in adjacent Oil Palm plantations, may have mediated the invasion of Clidemia hirta (Melastomataceae) into the diverse tropical lowland rain forest. To investigate this hypothesis, we established three 1 km transects from the forest/Oil Palm plantation boundary into the forest interior. We recorded the distribution of soil disturbance by wild pigs, C. hirta abundance, and environmental variables. These data were analyzed using a hierarchical Bayesian model that incorporated spatial auto-correlation in the environmental variables. As predicted, soil disturbance by wild pigs declined with distance from forest edge and C. hirta abundance was correlated with the level of soil disturbance. Importantly there was no effect of distance on C. hirta abundance, after controlling for the effect of soil disturbance. Clidemia hirta abundance was also correlated with the presence of canopy openings, but there was no significant association between the occurrence of canopy openings and distance from the edge. Increased levels of soil disturbance and C. hirta abundance were still detectable approximately 1 km from the edge, demonstrating the potential for exceptionally large-scale animal mediated edge effects.
Smoothness in Binomial Edge Ideals

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Hamid Damadi

2016-06-01

Full Text Available In this paper we study some geometric properties of the algebraic set associated to the binomial edge ideal of a graph. We study the singularity and smoothness of the algebraic set associated to the binomial edge ideal of a graph. Some of these algebraic sets are irreducible and some of them are reducible. If every irreducible component of the algebraic set is smooth we call the graph an edge smooth graph, otherwise it is called an edge singular graph. We show that complete graphs are edge smooth and introduce two conditions such that the graph G is edge singular if and only if it satisfies these conditions. Then, it is shown that cycles and most of trees are edge singular. In addition, it is proved that complete bipartite graphs are edge smooth.
Curvature Effects on the Vibration Characteristics of Doubly Curved Shallow Shells with General Elastic Edge Restraints

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Hui Shi

2015-01-01

Full Text Available Effects of curvature upon the vibration characteristics of doubly curved shallow shells are assessed in this paper. Boundary conditions of the shell are generally specified in terms of distributed elastic restraints along the edges. The classical homogeneous boundary supports can be easily simulated by setting the stiffnesses of restraining springs to either zero or infinite. Vibration problems of the shell are solved by a modified Fourier series method that each of the displacements is invariably expressed as a simple trigonometric series which converges uniformly and acceleratedly over the solution domain. All the unknown expansion coefficients are treated equally as a set of independent generalized coordinates and solved using the Rayleigh-Ritz technique. The current method provides a unified solution to the vibration problems of curved shallow shells involving different geometric properties and boundary conditions with no need of modifying the formulations and solution procedures. Extensive tabular and graphical results are presented to show the curvature effects on the natural frequencies of the shell with various boundary conditions.
Optimal Growth in Hypersonic Boundary Layers

Science.gov (United States)

Paredes, Pedro; Choudhari, Meelan M.; Li, Fei; Chang, Chau-Lyan

2016-01-01

The linear form of the parabolized linear stability equations is used in a variational approach to extend the previous body of results for the optimal, nonmodal disturbance growth in boundary-layer flows. This paper investigates the optimal growth characteristics in the hypersonic Mach number regime without any high-enthalpy effects. The influence of wall cooling is studied, with particular emphasis on the role of the initial disturbance location and the value of the spanwise wave number that leads to the maximum energy growth up to a specified location. Unlike previous predictions that used a basic state obtained from a self-similar solution to the boundary-layer equations, mean flow solutions based on the full Navier-Stokes equations are used in select cases to help account for the viscous- inviscid interaction near the leading edge of the plate and for the weak shock wave emanating from that region. Using the full Navier-Stokes mean flow is shown to result in further reduction with Mach number in the magnitude of optimal growth relative to the predictions based on the self-similar approximation to the base flow.
Cutting Edge Localisation in an Edge Profile Milling Head

NARCIS (Netherlands)

Fernandez Robles, Laura; Azzopardi, George; Alegre, Enrique; Petkov, Nicolai

2015-01-01

Wear evaluation of cutting tools is a key issue for prolonging their lifetime and ensuring high quality of products. In this paper, we present a method for the effective localisation of cutting edges of inserts in digital images of an edge profile milling head. We introduce a new image data set of
Edge colouring by total labellings

DEFF Research Database (Denmark)

Brandt, Stephan; Rautenbach, D.; Stiebitz, M.

2010-01-01

We introduce the concept of an edge-colouring total k-labelling. This is a labelling of the vertices and the edges of a graph G with labels 1, 2, ..., k such that the weights of the edges define a proper edge colouring of G. Here the weight of an edge is the sum of its label and the labels of its...
Rotor boundary layer development with inlet guide vane (IGV) wake impingement

Science.gov (United States)

Jia, Lichao; Zou, Tengda; Zhu, Yiding; Lee, Cunbiao

2018-04-01

This paper examines the transition process in a boundary layer on a rotor blade under the impingement of an inlet guide vane wake. The effects of wake strengths and the reduced frequency on the unsteady boundary layer development on a low-speed axial compressor were investigated using particle image velocimetry. The measurements were carried out at two reduced frequencies (fr = fIGVS0/U2i, fr = 1.35, and fr = 0.675) with the Reynolds number, based on the blade chord and the isentropic inlet velocity, being 97 500. At fr = 1.35, the flow separated at the trailing edge when the wake strength was weak. However, the separation was almost totally suppressed as the wake strength increased. For the stronger wake, both the wake's high turbulence and the negative jet behavior of the wake dominated the interaction between the unsteady wake and the separated boundary layer on the suction surface of the airfoil. The boundary layer displacement thickened first due to the negative jet effect. Then, as the disturbances developed underneath the wake, the boundary layer thickness reduced gradually. The high disturbance region convected downstream at a fraction of the free-stream velocity and spread in the streamwise direction. The separation on the suction surface was suppressed until the next wake's arrival. Because of the long recovery time at fr = 0.675, the boundary layer thickened gradually as the wake convected further downstream and finally separated due to the adverse pressure gradient. The different boundary layer states in turn affected the development of disturbances.
Charged particle reflection by a planar artificially structured boundary with electrostatic plugging

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R. M. Hedlof

2017-11-01

Full Text Available A classical trajectory Monte Carlo simulation is used to investigate an artificially structured boundary for confinement and control of charged particles. The artificially structured boundary considered here incorporates a planar sequence of conducting wires, where adjacent wires carry current in opposite directions. Such a configuration creates a sequence of magnetic cusps and was studied previously [C. A. Ordonez, J. Appl. Phys. 106, 024905 (2009]. The effect of introducing a sequence of electrodes for electrostatic plugging of the cusps is investigated. The results of the simulations are used to identify regions of parameter space in which particle losses through the cusps may be negligible in the single particle limit. A trap based on a cylindrical generalization of the artificially structured boundary presented here may lead to a method for confining non-neutral and partially neutralized plasmas along the edge, such that the bulk of a confined plasma is effectively free of externally applied electromagnetic fields.
Low-latitude boundary layer near noon: An open field line model

Science.gov (United States)

Lyons, L. R.; Schulz, M.; Pridmore-Brown, D. C.; Roeder, J. L.

1994-01-01

We propose that many features of the cusp and low-latitude boundary layer (LLBL) observed near noon MLT can be explained by interpreting the LLBL as being on open lines with an inner boundary at the separatrix between open and closed magnetic field lines. This interpretation places the poleward boundary of the LLBL and equatorward boundary of the cusp along the field line that bifurcates at the cusp neutral point. The interpretation accounts for the abrupt boundary of magnetosheath particles at the inner edge of the LLBL, a feature that is inconsistent with LLBL formation by diffusion onto closed field lines, and for the distribution of magnetosheath particles appearing more as one continuous region than as two distinct regions across the noon cusp/LLBL boundary. Furthermore, we can explain the existence of energetic radiation belt electrons and protons with differing pitch angle distributions within the LLBL and their abrupt cutoff at the poleward boundary of the LLBL. By modeling the LLBL and cusp region quantitatively, we can account for a hemispherical difference in the location of the equatorial boundary of the cusp that is observed to be dependent on the dipole tilt angle but not on the interplanetary magnetic field (IMF) x component. We also find important variations and hemispherical differences in that the size of the LLBL that should depend strongly upon the x component of the IMF. This prediction is observationally testable. Finally, we find that when the IMF is strongly northward, the LLBL may include a narrow region adjacent to the magnetopause where field lines are detached (i.e., have both ends connected to the IMF).
Choosing a heuristic and root node for edge ordering in BDD-based network reliability analysis

International Nuclear Information System (INIS)

Mo, Yuchang; Xing, Liudong; Zhong, Farong; Pan, Zhusheng; Chen, Zhongyu

2014-01-01

In the Binary Decision Diagram (BDD)-based network reliability analysis, heuristics have been widely used to obtain a reasonably good ordering of edge variables. Orderings generated using different heuristics can lead to dramatically different sizes of BDDs, and thus dramatically different running times and memory usages for the analysis of the same network. Unfortunately, due to the nature of the ordering problem (i.e., being an NP-complete problem) no formal guidelines or rules are available for choosing a good heuristic or for choosing a high-performance root node to perform edge searching using a particular heuristic. In this work, we make novel contributions by proposing heuristic and root node selection methods based on the concept of boundary sets for the BDD-based network reliability analysis. Empirical studies show that the proposed selection methods can help to generate high-performance edge ordering for most of studied cases, enabling the efficient BDD-based reliability analysis of large-scale networks. The proposed methods are demonstrated on different types of networks, including square lattice networks, torus lattice networks and de Bruijn networks
Probing the Structure of Our Solar System's Edge

Science.gov (United States)

Hensley, Kerry

2018-02-01

The boundary between the solar wind and the interstellar medium (ISM) at the distant edge of our solar system has been probed remotely and directly by spacecraft, but questions about its properties persist. What can models tell us about the structure of this region?The Heliopause: A Dynamic BoundarySchematic illustrating different boundaries of our solar system and the locations of the Voyager spacecraft. [Walt Feimer/NASA GSFCs Conceptual Image Lab]As our solar system travels through interstellar space, the magnetized solar wind flows outward and pushes back on the oncoming ISM, forming a bubble called the heliosphere. The clash of plasmas generates a boundary region called the heliopause, the shape of which depends strongly on the properties of the solar wind and the local ISM.Much of our understanding of the outer heliosphere and the local ISM comes from observations made by the International Boundary Explorer (IBEX) and the Voyager 1 and Voyager 2 spacecraft. IBEX makes global maps of the flux of neutral atoms, while Voyagers 1 and 2 record the plasma density and magnetic field parameters along their trajectories as they exit the solar system. In order to interpret the IBEX and Voyager observations, astronomers rely on complex models that must capture both global and local effects.Simulations of the plasma density in the meridional plane of the heliosphere due to the interaction of the solar wind with the ISM for the case of a relatively dense ISM with a weak magnetic field. [Adapted from Pogorelov et al. 2017]Modeling the Edge of the Solar SystemIn this study, Nikolai Pogorelov (University of Alabama in Huntsville) and collaborators use a hybrid magneto-hydrodynamical (MHD) and kinetic simulation to capture fully the physical processes happening in the outer heliosphere.MHD models have been used to understand many aspects of plasma flow in the heliosphere. However, they struggle to capture processes that are better described kinetically, like charge exchange
Invasive Brown Treesnake movements at road edges indicate road-crossing avoidance

Science.gov (United States)

Siers, Shane R.; Savidge, Julie S; Reed, Robert N.

2014-01-01

Roads have significant impacts on the dispersal of wildlife. Although this poses a threat to the abundance and diversity of desirable flora and fauna, it also affords some opportunity for enhancing control of invasive species. Roads are the most common terrain features that may affect the rate of landscape-scale movements of invasive Brown Treesnakes (Boiga irregularis) throughout Guam. We radio tracked 45 free-ranging Brown Treesnakes in close proximity to two roads in Guam and recorded instances where daily relocations of snakes spanned roads. Then we reconstructed observed movement histories with randomized turning angles, which served as a useful null hypothesis for assessing the effect of roads or road edge habitat on Brown Treesnake movement patterns. Random walk simulations demonstrated that Brown Treesnakes crossed these roads at a rate far lower than would be expected if snake movement was random with respect to roads and road edge habitat. We discuss two alternative hypotheses for these results: 1) habitat gaps posed by roads physically or behaviorally restrict snake movement; or 2) road edges provide preferred foraging habitat from which snakes are reluctant to depart. Because roads often form the boundaries of jurisdictional and management units, the effects of roads on the movement of invasive Brown Treesnakes will influence the prospects for success of future landscape-level suppression efforts.
Surface stress mediated image force and torque on an edge dislocation

Science.gov (United States)

Raghavendra, R. M.; Divya, Iyer, Ganesh; Kumar, Arun; Subramaniam, Anandh

2018-07-01

The proximity of interfaces gives prominence to image forces experienced by dislocations. The presence of surface stress alters the traction-free boundary conditions existing on free-surfaces and hence is expected to alter the magnitude of the image force. In the current work, using a combined simulation of surface stress and an edge dislocation in a semi-infinite body, we evaluate the configurational effects on the system. We demonstrate that if the extra half-plane of the edge dislocation is parallel to the surface, the image force (glide) is not altered due to surface stress; however, the dislocation experiences a torque. The surface stress breaks the 'climb image force' symmetry, thus leading to non-equivalence between positive and negative climb. We discover an equilibrium position for the edge dislocation in the positive 'climb geometry', arising due to a competition between the interaction of the dislocation stress fields with the surface stress and the image dislocation. Torque in the climb configuration is not affected by surface stress (remains zero). Surface stress is computed using a recently developed two-scale model based on Shuttleworth's idea and image forces using a finite element model developed earlier. The effect of surface stress on the image force and torque experienced by the dislocation monopole is analysed using illustrative 3D models.
Turbulent/non-turbulent interfaces detected in DNS of incompressible turbulent boundary layers

Science.gov (United States)

Watanabe, T.; Zhang, X.; Nagata, K.

2018-03-01

The turbulent/non-turbulent interface (TNTI) detected in direct numerical simulations is studied for incompressible, temporally developing turbulent boundary layers at momentum thickness Reynolds number Reθ ≈ 2000. The outer edge of the TNTI layer is detected as an isosurface of the vorticity magnitude with the threshold determined with the dependence of the turbulent volume on a threshold level. The spanwise vorticity magnitude and passive scalar are shown to be good markers of turbulent fluids, where the conditional statistics on a distance from the outer edge of the TNTI layer are almost identical to the ones obtained with the vorticity magnitude. Significant differences are observed for the conditional statistics between the TNTI detected by the kinetic energy and vorticity magnitude. A widely used grid setting determined solely from the wall unit results in an insufficient resolution in a streamwise direction in the outer region, whose influence is found for the geometry of the TNTI and vorticity jump across the TNTI layer. The present results suggest that the grid spacing should be similar for the streamwise and spanwise directions. Comparison of the TNTI layer among different flows requires appropriate normalization of the conditional statistics. Reference quantities of the turbulence near the TNTI layer are obtained with the average of turbulent fluids in the intermittent region. The conditional statistics normalized by the reference turbulence characteristics show good quantitative agreement for the turbulent boundary layer and planar jet when they are plotted against the distance from the outer edge of the TNTI layer divided by the Kolmogorov scale defined for turbulent fluids in the intermittent region.
An application of the edge effect in measuring accessibility to multiple food retailer types in Southwestern Ontario, Canada

Science.gov (United States)

2011-01-01

Background Trends in food retailing associated with the consolidation of smaller-format retailers into fewer, larger-format supercentres have left some rural areas with fewer sources of nutritious, affordable food. Access to nutritious, affordable food is essential for good dietary habits and combating health issues such as type-2 diabetes, obesity, and cardiovascular disease. Many studies on food environments use inaccurate or incomplete methods for locating food retailers, which may be responsible for mischaracterising food deserts. This study uses databases of every residence in and every food retailer in and around Middlesex County, Ontario, Canada. Residences were geocoded to their precise address, and network analysis techniques were performed in a geographic information system (GIS) to determine distances between every residence and different types of food retailers (grocery stores, fast food, fruit and vegetable sources, grocery stores plus fruit and vegetable sources, variety stores), both when considering and neglecting facilities outside the area of study, to account for a deficiency in analysis termed the 'edge effect'. Results Analysis of household accessibility to food outlets by neighbourhood socioeconomic distress level indicated that residents in the most distressed neighbourhoods tended to have better accessibility to all types of food retailers. In the most distressed neighbourhoods, 79 percent of residences were within walking distance of a grocery store, compared to only 10 percent in the least distressed neighbourhoods. When the edge effect was neglected, 37 percent of distance estimates proved inaccurate. Average accessibility to all food retailer types improved dramatically when food outlets adjacent to the study area were considered, thereby controlling for the edge effect. Conclusion By neglecting to consider food retailers just outside study area boundaries, previous studies may significantly over-report the actual distance necessary to
An application of the edge effect in measuring accessibility to multiple food retailer types in southwestern Ontario, Canada.

Science.gov (United States)

Sadler, Richard C; Gilliland, Jason A; Arku, Godwin

2011-05-15

Trends in food retailing associated with the consolidation of smaller-format retailers into fewer, larger-format supercentres have left some rural areas with fewer sources of nutritious, affordable food. Access to nutritious, affordable food is essential for good dietary habits and combating health issues such as type-2 diabetes, obesity, and cardiovascular disease. Many studies on food environments use inaccurate or incomplete methods for locating food retailers, which may be responsible for mischaracterising food deserts. This study uses databases of every residence in and every food retailer in and around Middlesex County, Ontario, Canada. Residences were geocoded to their precise address, and network analysis techniques were performed in a geographic information system (GIS) to determine distances between every residence and different types of food retailers (grocery stores, fast food, fruit and vegetable sources, grocery stores plus fruit and vegetable sources, variety stores), both when considering and neglecting facilities outside the area of study, to account for a deficiency in analysis termed the 'edge effect'. Analysis of household accessibility to food outlets by neighbourhood socioeconomic distress level indicated that residents in the most distressed neighbourhoods tended to have better accessibility to all types of food retailers. In the most distressed neighbourhoods, 79 percent of residences were within walking distance of a grocery store, compared to only 10 percent in the least distressed neighbourhoods. When the edge effect was neglected, 37 percent of distance estimates proved inaccurate. Average accessibility to all food retailer types improved dramatically when food outlets adjacent to the study area were considered, thereby controlling for the edge effect. By neglecting to consider food retailers just outside study area boundaries, previous studies may significantly over-report the actual distance necessary to travel for food. Research on

An application of the edge effect in measuring accessibility to multiple food retailer types in Southwestern Ontario, Canada

Directory of Open Access Journals (Sweden)

Arku Godwin

2011-05-01

Full Text Available Abstract Background Trends in food retailing associated with the consolidation of smaller-format retailers into fewer, larger-format supercentres have left some rural areas with fewer sources of nutritious, affordable food. Access to nutritious, affordable food is essential for good dietary habits and combating health issues such as type-2 diabetes, obesity, and cardiovascular disease. Many studies on food environments use inaccurate or incomplete methods for locating food retailers, which may be responsible for mischaracterising food deserts. This study uses databases of every residence in and every food retailer in and around Middlesex County, Ontario, Canada. Residences were geocoded to their precise address, and network analysis techniques were performed in a geographic information system (GIS to determine distances between every residence and different types of food retailers (grocery stores, fast food, fruit and vegetable sources, grocery stores plus fruit and vegetable sources, variety stores, both when considering and neglecting facilities outside the area of study, to account for a deficiency in analysis termed the 'edge effect'. Results Analysis of household accessibility to food outlets by neighbourhood socioeconomic distress level indicated that residents in the most distressed neighbourhoods tended to have better accessibility to all types of food retailers. In the most distressed neighbourhoods, 79 percent of residences were within walking distance of a grocery store, compared to only 10 percent in the least distressed neighbourhoods. When the edge effect was neglected, 37 percent of distance estimates proved inaccurate. Average accessibility to all food retailer types improved dramatically when food outlets adjacent to the study area were considered, thereby controlling for the edge effect. Conclusion By neglecting to consider food retailers just outside study area boundaries, previous studies may significantly over-report the
Experience with a second language affects the use of fundamental frequency in speech segmentation

Science.gov (United States)

Broersma, Mirjam; Cho, Taehong; Kim, Sahyang; Martínez-García, Maria Teresa; Connell, Katrina

2017-01-01

This study investigates whether listeners’ experience with a second language learned later in life affects their use of fundamental frequency (F0) as a cue to word boundaries in the segmentation of an artificial language (AL), particularly when the cues to word boundaries conflict between the first language (L1) and second language (L2). F0 signals phrase-final (and thus word-final) boundaries in French but word-initial boundaries in English. Participants were functionally monolingual French listeners, functionally monolingual English listeners, bilingual L1-English L2-French listeners, and bilingual L1-French L2-English listeners. They completed the AL-segmentation task with F0 signaling word-final boundaries or without prosodic cues to word boundaries (monolingual groups only). After listening to the AL, participants completed a forced-choice word-identification task in which the foils were either non-words or part-words. The results show that the monolingual French listeners, but not the monolingual English listeners, performed better in the presence of F0 cues than in the absence of such cues. Moreover, bilingual status modulated listeners’ use of F0 cues to word-final boundaries, with bilingual French listeners performing less accurately than monolingual French listeners on both word types but with bilingual English listeners performing more accurately than monolingual English listeners on non-words. These findings not only confirm that speech segmentation is modulated by the L1, but also newly demonstrate that listeners’ experience with the L2 (French or English) affects their use of F0 cues in speech segmentation. This suggests that listeners’ use of prosodic cues to word boundaries is adaptive and non-selective, and can change as a function of language experience. PMID:28738093
Charge transfer of edge states in zigzag silicene nanoribbons with Stone–Wales defects from first-principles

Energy Technology Data Exchange (ETDEWEB)

Ting, Xie [College of Mathematics and Statistics, Chongqing University, Chongqing 401331 (China); School of Mathematics and Statistic, Chongqing University of Technology, Chongqing 400054 (China); Rui, Wang, E-mail: rcwang@cqu.edu.cn [Institute for Structure and Function and Department of Physics, Chongqing University, Chongqing 400044 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Science, Beijing 100190 (China); Shaofeng, Wang [Institute for Structure and Function and Department of Physics, Chongqing University, Chongqing 400044 (China); Xiaozhi, Wu, E-mail: xiaozhiwu@cqu.edu.cn [Institute for Structure and Function and Department of Physics, Chongqing University, Chongqing 400044 (China)

2016-10-15

Highlights: • The properties of SW defects in silicene and ZSNRs are obtained. • The SW defects at the edge of ZSNRs induce a sizable gap. • The charge transfer of edge states is resulted from SW defects in ZSNRS. - Abstract: Stone–Wales (SW) defects are favorably existed in graphene-like materials with honeycomb lattice structure and potentially employed to change the electronic properties in band engineering. In this paper, we investigate structural and electronic properties of SW defects in silicene sheet and its nanoribbons as a function of their concentration using the methods of periodic boundary conditions with first-principles calculations. We first calculate the formation energy, structural properties, and electronic band structures of SW defects in silicene sheet, with dependence on the concentration of SW defects. Our results show a good agreement with available values from the previous first-principles calculations. The energetics, structural aspects, and electronic properties of SW defects with dependence on defect concentration and location in edge-hydrogenated zigzag silicene nanoribbons are obtained. For all calculated concentrations, the SW defects prefer to locate at the edge due to the lower formation energy. The SW defects at the center of silicene nanoribbons slightly influence on the electronic properties, whereas the SW defects at the edge of silicene nanoribbons split the degenerate edge states and induce a sizable gap, which depends on the concentration of defects. It is worth to find that the SW defects produce a perturbation repulsive potential, which leads the decomposed charge of edge states at the side with defect to transfer to the other side without defect.
Edge fluctuation studies in Heliotron J

International Nuclear Information System (INIS)

Mizuuchi, T.; Chechkin, V.V.; Ohashi, K.; Sorokovoy, E.L.; Chechkin, A.V.; Gonchar, V.Yu.; Takahashi, K.; Kobayashi, S.; Nagasaki, K.; Okada, H.; Yamamoto, S.; Sano, F.; Kondo, K.; Nishino, N.; Kawazome, H.; Shidara, H.; Kaneko, S.; Fukagawa, Y.; Morita, Y.; Nakazawa, S.; Nishio, S.; Tsuboi, S.; Yamada, M.

2005-01-01

Low frequency and small-scale fluctuations of density and potential near the last closed flux surface are investigated by using Langmuir probes for the second harmonic ECH plasmas in a helical-axis heliotron device, Heliotron J. The existence of a plasma layer with a radial electric field shear was indicated near the last closed flux surface. Near this layer, the reversal of phase velocity and de-correlation of the fluctuations were observed. On the other hand, it is suggested that a considerable fraction of the fluctuation induced particle flux is carried off through the intermittent events. Preliminary analyses to classify the PDFs of the ion-saturation current fluctuation as stable Levy distributions demonstrate that the Levy index decreases from the inner to the outer region of edge plasma, suggesting that the PDFs near the boundary region of Heliotron J are nearly Gaussian, whereas at the outer regions of plasma they become strongly non-Gaussian
Grain boundary motion and grain rotation in aluminum bicrystals: recent experiments and simulations

International Nuclear Information System (INIS)

Molodov, D A; Barrales-Mora, L A; Brandenburg, J-E

2015-01-01

The results of experimental and computational efforts over recent years to study the motion of geometrically different grain boundaries and grain rotation under various driving forces are briefly reviewed. Novel in-situ measuring techniques based on orientation contrast imaging and applied simulation techniques are described. The experimental results obtained on specially grown aluminum bicrystals are presented and discussed. Particularly, the faceting and migration behavior of low angle grain boundaries under the curvature force is addressed. In contrast to the pure tilt boundaries, which remained flat/faceted and immobile during annealing at elevated temperatures, mixed tilt-twist boundaries readily assumed a curved shape and steadily moved under the capillary force. Computational analysis revealed that this behavior is due to the inclinational anisotropy of grain boundary energy, which in turn depends on boundary geometry. The shape evolution and shrinkage kinetics of cylindrical grains with different tilt and mixed boundaries were studied by molecular dynamics simulations. The mobility of low angle <100> boundaries with misorientation angles higher than 10°, obtained by both the experiments and simulations, was found not to differ from that of the high angle boundaries, but decreases essentially with further decrease of misorientation. The shape evolution of the embedded grains in simulations was found to relate directly to results of the energy computations. Further simulation results revealed that the shrinkage of grains with pure tilt boundaries is accompanied by grain rotation. In contrast, grains with the tilt-twist boundaries composed of dislocations with the mixed edge-screw character do not rotate during their shrinkage. Stress driven boundary migration in aluminium bicrystals was observed to be coupled to a tangential translation of the grains. The activation enthalpy of high angle boundary migration was found to vary non-monotonically with
The scaling of edge parameters in jet with plasma input power

International Nuclear Information System (INIS)

Erents, S.K.; McCracken, G.M.; Harbour, P.J.; Clement, S.; Summers, D.D.R.; Tagle, J.A.; Kock, L. de

1989-01-01

The scaling of edge parameters of density and temperature with central density and ohmic power in JET has been presented previously for the discrete limiter geometry and more recently for the new belt limiter configuration. However, the scaling with plasma current (I p ) is difficult to interpret because varying I p does not only change the input power but also the safety factor qs and consequently the SOL thickness. The use of additional heating at constant current allows more direct observation of the effects of changing heating power. In this paper we present data in which the plasma input power is increased by ICRH, (Pt<20MW), using a 3MA target plasma, and compare data for different plasma currents using discrete and belt limiter geometries. Edge data is presented from Langmuir probes in tiles at the top of the torus, when the tokamak is operated in single null magnetic separatrix (divertor) mode, as well as for probes in the main plasma boundary to contrast these data with limiter data. (author) 3 refs., 4 figs
Development of edge effects around experimental ecosystem hotspots is affected by edge density and matrix type

Science.gov (United States)

Ecological edge effects are sensitive to landscape context. In particular, edge effects can be altered by matrix type and by the presence of other nearby edges. We experimentally altered patch configurations in an African savanna to determine how edge density and matrix type influence edge effect de...
Design & fabrication of two seated aircraft with an advanced rotating leading edge wing

Science.gov (United States)

Al Ahmari, Saeed Abdullah Saeed

The title of this thesis is "Design & Fabrication of two Seated Aircraft with an Advanced Rotating Leading Edge Wing", this gives almost a good description of the work has been done. In this research, the moving surface boundary-layer control (MSBC) concept was investigated and implemented. An experimental model was constructed and tested in wind tunnel to determine the aerodynamic characteristics using the leading edge moving surface of modified semi-symmetric airfoil NACA1214. The moving surface is provided by a high speed rotating cylinder, which replaces the leading edge of the airfoil. The angle of attack, the cylinder surfaces velocity ratio Uc/U, and the flap deflection angle effects on the lift and drag coefficients and the stall angle of attack were investigated. This new technology was applied to a 2-seat light-sport aircraft that is designed and built in the Aerospace Engineering Department at KFUPM. The project team is led by the aerospace department chairman Dr. Ahmed Z. AL-Garni and Dr. Wael G. Abdelrahman and includes graduate and under graduate student. The wing was modified to include a rotating cylinder along the leading edge of the flap portion. This produced very promising results such as the increase of the maximum lift coefficient at Uc/U=3 by 82% when flaps up and 111% when flaps down at 40° and stall was delayed by 8degrees in both cases. The laboratory results also showed that the effective range of the leading-edge rotating cylinder is at low angles of attack which reduce the need for higher angles of attack for STOL aircraft.
Optically Unraveling the Edge Chirality-Dependent Band Structure and Plasmon Damping in Graphene Edges.

Science.gov (United States)

Duan, Jiahua; Chen, Runkun; Cheng, Yuan; Yang, Tianzhong; Zhai, Feng; Dai, Qing; Chen, Jianing

2018-05-01

The nontrivial topological origin and pseudospinorial character of electron wavefunctions make edge states possess unusual electronic properties. Twenty years ago, the tight-binding model calculation predicted that zigzag termination of 2D sheets of carbon atoms have peculiar edge states, which show potential application in spintronics and modern information technologies. Although scanning probe microscopy is employed to capture this phenomenon, the experimental demonstration of its optical response remains challenging. Here, the propagating graphene plasmon provides an edge-selective polaritonic probe to directly detect and control the electronic edge state at ambient condition. Compared with armchair, the edge-band structure in the bandgap gives rise to additional optical absorption and strongly absorbed rim at zigzag edge. Furthermore, the optical conductivity is reconstructed and the anisotropic plasmon damping in graphene systems is revealed. The reported approach paves the way for detecting edge-specific phenomena in other van der Waals materials and topological insulators. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
An analysis of the relaxation of laminar boundary layer on a flat plate after passage of an interface with application to expansion-tube flows

Science.gov (United States)

Gupta, R. N.

1972-01-01

The relaxation of the accelerating-gas boundary layer to the test-gas boundary layer over a flat plate in an expansion tube is analyzed. Several combinations of test gas and acceleration gas are considered. The problem is treated in two conically similar limits: (1) when the time lag between the arrival of the shock and the interface at the leading edge of the plate is very large, and (2) when this lag is negligible. The time-dependent laminar-boundary-layer equations of a binary mixture of perfect gases are taken as the flow-governing equations. This coupled set of differential equations, written in terms of the Lam-Crocco variables, has been solved by a line-relaxation finite-difference techniques. The results presented include the Stanton number and the local skin-friction coefficient as functions of shock Mach number and the nondimensional distance-time variable. The results indicate that more than 95 percent of the test-gas boundary layer exists over a length, measured from the leading edge of the plate, equal to about three-tenths of the distance traversed by the interface in the free stream.
Modification of boundary plasma behavior by Ion Bernstein Wave heating on the HT-7 tokamak

International Nuclear Information System (INIS)

Xu, G.S.; Wan, B.N.; Song, M.; Ling, B.L.; Li, C.F.; Li, J.

2003-01-01

The boundary plasma behavior during Ion Bernstein Wave heating was investigated using Langmuir probe arrays on the HT-7 tokamak. A distinct weak turbulence regime was reproducibly observed in the 30 MHz IBW heated plasmas with RF power larger than 120 kW, which resulted in a particle confinement improvement of a factor of 2. The strong suppression and decorrelation effect of fluctuations resulted in the turbulent particle flux dropping by more than an order of magnitude in the plasma boundary region. An additional inward radial electric field and associated poloidal ExB flows were produced, which could account for the additional poloidal velocity in the electron diamagnetic direction at some radial locations of the boundary plasma. The electrostatic fluctuations were nearly completely decorrelated in the high frequency region and only low frequency fluctuations remained. The poloidal correlation was considerably reduced in the high poloidal wave number region and only the fluctuations with long poloidal wavelength remained. Three-wave nonlinear phase coupling between the whole frequency domain and the very low frequency region increased significantly in both the plasma edge and the SOL. Quite low frequency fluctuations (about 5 kHz) were generated, which dominated the boundary turbulence during IBW heating. Detailed analyses suggested that, when an IBW with a frequency of 30 MHz was launched into a plasma with the toroidal magnetic field between 1.75 T and 2.0 T, the ion cyclotron resonant layer of 5/2.D was located in the plasma edge region. The poloidal ExB sheared flows generated by IBW near this layer due to a ponderomotive interaction were found to be the mechanism underlying these phenomena. (author)
HREM investigation of the structure of the Σ5(310)/[001] symmetric tilt grain boundaries in Nb

International Nuclear Information System (INIS)

King, W.E.; Compbell, G.H.; Coombs, A.; Ruehle, M.

1991-01-01

This paper reports on atomistic simulations using interatomic potentials for Nb developed employing the embedded atom method (EAM) and the model generalized pseudopotential theory (MGPT) that have indicated a possible cusp at the Σ5 (310) orientation in the energy vs tilt angle curves for left-angle 001 right-angle symmetric tilt grain boundaries. In addition, the most stable structure predicted using EAM exhibits shifts of one crystal relative to the other along the tilt axis and along the direction perpendicular to the tilt axis lying in the boundary plane. The structure predicted using the MGPT was mirror symmetric across the plane of the grain boundary. This boundary has been prepared for experimental study using the ultra high vacuum diffusion bonding method. A segment of this boundary has been studied using high resolution electron microscopy
Plasma boundary experiments on DIII-D tokamak

International Nuclear Information System (INIS)

Mahdavi, M.A.; Brooks, N.; Jackson, G.L.; Langhorn, A.; Leikind, B.; Lippmann, S.; Luxon, J.; Petersen, P.; Petrie, T.; Stambaugh, R.D.; Simonen, T.C.; Staebler, G.; Buchenauer, D.; Futch, A.; Hill, D.N.; Rensink, M.; Hogan, J.; Menon, M.; Mioduszewski, P.; Owen, L.; Matthews, G.

1990-06-01

A survey of the boundary physics research on the DIII-D tokamak and an outline of the DIII-D Advanced Divertor Program (ADP) is presented. We will present results of experiments on impurity control, impurity transport, neutral particle transport, and particle effects on core confinement over a wide range of plasma parameters, I p approx-lt 3 MA, β T approx-lt 10.7%, P(auxiliary) approx-lt 20 MW. Based on the understanding gained in these studies, we in collaboration with a number of other laboratories have devised a series of experiments (ADP) to modify the core plasma conditions through changes in the edge electric field, neutral recycling, and plasma surface interactions. 41 refs., 8 figs., 1 tab
CHARACTERISTICS OF EPIRETINAL MEMBRANE REMNANT EDGE BY OPTICAL COHERENCE TOMOGRAPHY AFTER PARS PLANA VITRECTOMY.

Science.gov (United States)

Gaber, Raouf; You, Qi Sheng; Muftuoglu, Ilkay Kilic; Alam, Mostafa; Tsai, Frank F; Mendoza, Nadia; Freeman, William R

2017-11-01

To evaluate the incidence, characteristics, and the progression of epiretinal membrane (ERM) remnant edge seen by optical coherence tomography after ERM peeling. A retrospective chart review was conducted for 86 eyes of 85 consecutive patients who were diagnosed with ERM and underwent pars plana vitrectomy for epiretinal membrane peeling between 2013 and 2014. Data collected and analyzed included age, gender, preoperative and postoperative visual acuity, use of indocyanine green dye to stain internal limiting membrane, tamponade used after vitrectomy, ERM edge boundaries, presence of cystoid macular edema, and central foveal thickness. An ERM remnant edge was detected in 33/86 study eyes (38.4%) at the first postoperative optical coherence tomography scan. Compared with those without an ERM remnant, patients with an ERM remnant after surgery were significantly older at baseline and had a higher incidence of ERM recurrence at their last visit. They were not significantly different in terms of gender, preoperative and postoperative visual acuity, reduction of central foveal thickness from baseline, proportion of eyes with preoperative ERM elevation on optical coherence tomography, presence of macular edema before surgery, intraoperative use of indocyanine green staining for ILM peeling, or tamponade used. Based on the edge morphology, we classified the ERM remnant into three types: Type 1 was flat and blended with the retina (14/33 eyes, 42.4%), Type 2 was flat but stepped (17/33 eyes, 51.5%), and Type 3 was elevated (2/33 eyes, 6.0%). A significantly higher risk of ERM recurrence was seen in Type 2 and Type 3 ERM remnants (75% and 100%, respectively) than Type 1 ERM remnants (10%). An ERM remnant edge was detected by optical coherence tomography after ERM peeling in 38.4% of eyes. The presence of a postoperative ERM edge was associated with a higher risk of ERM recurrence, particularly in Type 2 and Type 3 ERM remnants.
Infective endocarditis following transcatheter edge-to-edge mitral valve repair: A systematic review.

Science.gov (United States)

Asmarats, Lluis; Rodriguez-Gabella, Tania; Chamandi, Chekrallah; Bernier, Mathieu; Beaudoin, Jonathan; O'Connor, Kim; Dumont, Eric; Dagenais, François; Paradis, Jean-Michel; Rodés-Cabau, Josep

2018-05-10

To assess the clinical characteristics, management, and outcomes of patients diagnosed with infective endocarditis (IE) after edge-to-edge mitral valve repair with the MitraClip device. Transcatheter edge-to-edge mitral valve repair has emerged as an alternative to surgery in high-risk patients. However, few data exist on IE following transcatheter mitral procedures. Four electronic databases (PubMed, Google Scholar, Embase, and Cochrane Library) were searched for original published studies on IE after edge-to-edge transcatheter mitral valve repair from 2003 to 2017. A total of 10 publications describing 12 patients with definitive IE (median age 76 years, 55% men) were found. The mean logistic EuroSCORE/EuroSCORE II were 41% and 45%, respectively. The IE episode occurred early (within 12 months post-procedure) in nine patients (75%; within the first month in five patients). Staphylococcus aureus was the most frequent (60%) causal microorganism, and severe mitral regurgitation was present in all cases but one. Surgical mitral valve replacement (SMVR) was performed in most (67%) patients, and the mortality associated with the IE episode was high (42%). IE following transcatheter edge-to-edge mitral valve repair is a rare but life-threatening complication, usually necessitating SMVR despite the high-risk profile of the patients. These results highlight the importance of adequate preventive measures and a prompt diagnosis and treatment of this serious complication. © 2018 Wiley Periodicals, Inc.
Influence of crystallography and bonding on the structure and migration of irrational interphase boundaries

Science.gov (United States)

Aaronson, H. I.

2006-03-01

Interphase boundary structure developed during precipitation from solid solution and during massive transformations is considered in diverse alloy systems in the presence of differences in stacking sequence across interphase boundaries. Linear misfit compensating defects, including misfit dislocations, structural disconnections, and misfit disconnections, are present over a wide range of crystallographie when both phases have metallic bonding. Misfit dislocations have also been observed when both phases have covalent bonding ( e.g., US: β US2 by Sole and van der Walt). These defects are also found when one phase is ionic and the other is metallic (Nb∶Al2O3 by Rühle et al.), albeit when the latter is formed by vapor deposition. However, when bonding is metallic in one phase but significantly covalent in the other, the structure of the interphase boundary appears to depend upon the strength of the covalent bonding relative to that in the metallically bonded phase. When this difference is large, growth can take place as if it were occurring at a free surface, resulting in orientation relationships that are irrational and conjugate habit planes that are ill matched ( e.g., ZrN: α Zr-N by Li et al. and Xe(solid):Al-Xe by Kishida and Yamaguchi). At lower levels of bonding directionality and strength, crystallography is again irrational, but now edge-to-edge-based low-energy structures can replace linear misfit compensating defects (γm:TiAl:αTi-Al by Reynolds et al.). In the perhaps still smaller difference case of Widmanstätten cementite precipitated from austenite, one orientation relationship yields plates with linear misfit compensating defects at their broad faces whereas another (presumably nucleated at different types of site) produces laths with poorly defined shapes and interfacial structures. Hence, Hume-Rothery-type bonding considerations can markedly affect interphase boundary structure and thus the mechanisms, kinetics, and morphology of growth.
Nonreference Medical Image Edge Map Measure

Directory of Open Access Journals (Sweden)

Karen Panetta

2014-01-01

Full Text Available Edge detection is a key step in medical image processing. It is widely used to extract features, perform segmentation, and further assist in diagnosis. A poor quality edge map can result in false alarms and misses in cancer detection algorithms. Therefore, it is necessary to have a reliable edge measure to assist in selecting the optimal edge map. Existing reference based edge measures require a ground truth edge map to evaluate the similarity between the generated edge map and the ground truth. However, the ground truth images are not available for medical images. Therefore, a nonreference edge measure is ideal for medical image processing applications. In this paper, a nonreference reconstruction based edge map evaluation (NREM is proposed. The theoretical basis is that a good edge map keeps the structure and details of the original image thus would yield a good reconstructed image. The NREM is based on comparing the similarity between the reconstructed image with the original image using this concept. The edge measure is used for selecting the optimal edge detection algorithm and optimal parameters for the algorithm. Experimental results show that the quantitative evaluations given by the edge measure have good correlations with human visual analysis.
New edge magnetoplasmon for a two-dimensional electron gas in a ring geometry

International Nuclear Information System (INIS)

Proetto, C.R.

1992-09-01

The dynamical response of a classical two-dimensional electron gas confined in a ring geometry under a perpendicular magnetic field is analysed. Within the hydrodynamical approach and in the strong magnetic field limit, a new set of antidot edge magnetoplasmons is obtained, corresponding to density oscillations circulating along the inner boundary of the ring and whose frequency increases with magnetic field. The associated self-induced distribution of densities and currents are presented, together with an analysis of the size dependence of these perimeter waves. (author). 15 refs, 4 figs
Experimental investigation of a supercritical airfoil boundary layer in pitching motion

Energy Technology Data Exchange (ETDEWEB)

Masdari, Mehran; Tabrizian, Arshia [Faculty of New Science and Technology, University of Tehran, Tehran (Iran, Islamic Republic of); Jahanmiri, Mohsen; Gorji, Mohamamd [Dept. of Mechanical and Aerospace Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of); Soltani, Mohammad Reza [Dept. of Aerospace Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

2017-01-15

In this study, the boundary layer velocity profile on the upper surface of a supercritical airfoil in a forced sinusoidal pitching motion was measured and experimentally investigated. Measurements were performed using a boundary layer rake, including total pressure tubes positioned at 25 % of the chord far from the leading edge on the upper surface. For static measurements, the effects of the angle of attack between −3° and 14° and free-stream velocity between 40 m/s and 70 m/s were investigated; for dynamic measurements, the effects of oscillation amplitude variation between ±3° and ±10°, reduced frequency from 0.007 to 0.0313, and mean angle of attack between −3° and 6° were studied during one oscillation cycle. Results indicated that the boundary layer thickness decreased in upstroke motion. Increasing the oscillation frequency led to the extension of hysteresis loops. Fast Fourier transform was used on pressure signals to study the amplitude of the dominant frequency in the velocity profile. Spectral analysis showed that the dominant forced frequency of oscillation in the boundary layer and the amplitude of this frequency were varied by increasing the reduced frequency and other parameters.
Edge responses are different in edges under natural versus anthropogenic influence: a meta-analysis using ground beetles.

Science.gov (United States)

Magura, Tibor; Lövei, Gábor L; Tóthmérész, Béla

2017-02-01

Most edges are anthropogenic in origin, but are distinguishable by their maintaining processes (natural vs. continued anthropogenic interventions: forestry, agriculture, urbanization). We hypothesized that the dissimilar edge histories will be reflected in the diversity and assemblage composition of inhabitants. Testing this "history-based edge effect" hypothesis, we evaluated published information on a common insect group, ground beetles (Coleoptera: Carabidae) in forest edges. A meta-analysis showed that the diversity-enhancing properties of edges significantly differed according to their history. Forest edges maintained by natural processes had significantly higher species richness than their interiors, while edges with continued anthropogenic influence did not. The filter function of edges was also essentially different depending on their history. For forest specialist species, edges maintained by natural processes were penetrable, allowing these species to move right through the edges, while edges still under anthropogenic interventions were impenetrable, preventing the dispersal of forest specialists out of the forest. For species inhabiting the surrounding matrix (open-habitat and generalist species), edges created by forestry activities were penetrable, and such species also invaded the forest interior. However, natural forest edges constituted a barrier and prevented the invasion of matrix species into the forest interior. Preserving and protecting all edges maintained by natural processes, and preventing anthropogenic changes to their structure, composition, and characteristics are key factors to sustain biodiversity in forests. Moreover, the increasing presence of anthropogenic edges in a landscape is to be avoided, as they contribute to the loss of biodiversity. Simultaneously, edges under continued anthropogenic disturbance should be restored by increasing habitat heterogeneity.

Structure and transport at grain boundaries in polycrystalline olivine: An atomic-scale perspective

Science.gov (United States)

Mantisi, Boris; Sator, Nicolas; Guillot, Bertrand

2017-12-01

Structure and transport properties at grain boundaries in polycrystalline olivine have been investigated at the atomic scale by molecular dynamics simulation (MD) using an empirical ionocovalent interaction potential. On the time scale of the simulation (a few tens of nanoseconds for a system size of ∼650,000 atoms) grain boundaries and grain interior were identified by mapping the atomic displacements along the simulation run. In the investigated temperature range (1300-1700 K) the mean thickness of the grain boundary phase is evaluated between 0.5 and 2 nm, a value which depends on temperature and grain size. The structure of the grain boundary phase is found to be disordered (amorphous-like) and is different from the one exhibited by the supercooled liquid. The self-diffusion coefficients of major elements in the intergranular region range from ∼10-13 to 10-10 m2/s between 1300 and 1700 K (with DSigb Kubo relation expressing the viscosity as function of the stress tensor time correlation function. In spite of a slow convergence of the calculation by MD, the grain boundary viscosity was estimated about ∼105 Pa s at 1500 K, a value in agreement with high-temperature viscoelastic relaxation data. An interesting information gained from MD is that sliding at grain boundaries is essentially controlled by the internal friction between the intergranular phase and the grain edges.
Nanoindentation near the edge

Science.gov (United States)

J.E. Jakes; C.R. Frihart; J.F. Beecher; R.J. Moon; P.J. Resto; Z.H. Melgarejo; O.M. Saurez; H. Baumgart; A.A. Elmustafa; D.S. Stone

2009-01-01

Whenever a nanoindent is placed near an edge, such as the free edge of the specimen or heterophase interface intersecting the surface, the elastic discontinuity associated with the edge produces artifacts in the load-depth data. Unless properly handled in the data analysis, the artifacts can produce spurious results that obscure any real trends in properties as...
Dynamic programming in parallel boundary detection with application to ultrasound intima-media segmentation.

Science.gov (United States)

Zhou, Yuan; Cheng, Xinyao; Xu, Xiangyang; Song, Enmin

2013-12-01

Segmentation of carotid artery intima-media in longitudinal ultrasound images for measuring its thickness to predict cardiovascular diseases can be simplified as detecting two nearly parallel boundaries within a certain distance range, when plaque with irregular shapes is not considered. In this paper, we improve the implementation of two dynamic programming (DP) based approaches to parallel boundary detection, dual dynamic programming (DDP) and piecewise linear dual dynamic programming (PL-DDP). Then, a novel DP based approach, dual line detection (DLD), which translates the original 2-D curve position to a 4-D parameter space representing two line segments in a local image segment, is proposed to solve the problem while maintaining efficiency and rotation invariance. To apply the DLD to ultrasound intima-media segmentation, it is imbedded in a framework that employs an edge map obtained from multiplication of the responses of two edge detectors with different scales and a coupled snake model that simultaneously deforms the two contours for maintaining parallelism. The experimental results on synthetic images and carotid arteries of clinical ultrasound images indicate improved performance of the proposed DLD compared to DDP and PL-DDP, with respect to accuracy and efficiency. Copyright © 2013 Elsevier B.V. All rights reserved.
HEOS-2 observations of the boundary layer from the magnetopause to the ionosphere

International Nuclear Information System (INIS)

Formisano, V.

1980-01-01

HEOS-2 low energy electron data (10 eV - 3.7 keV) from the LPS Frascati plasma experiment have been used to identify three different magnetospheric electron populations. Magnetosheath-like electron energy spectra (35-50 eV) are characteristic of the plasma mantle, entry layer and cusps from the magnetopause down to 2-3 Rsub(E). Plasma sheet electrons (energy > 1 keV) are found at all local times, with strong intensities in the early morning quadrant and weaker intensities in the afternoon quadrant. The plasma sheet shows a well defined inner edge at all local times and latitudes, the inner edge coinciding probably with the plasmapause. The plasma sheet does not reach the magnetopause, but it is separated from it by a boundary layer electron population that is very distinct from the other two electron populations, most electrons having energies 100-300 eV. These three electron populations are mapped from the magnetopause down to the high latitude near earth regions. The boundary layer extends along the magnetopause up to 5-7 Rsub(E) above the equator; at higher latitudes it follows the magnetic lines of force and it is found closer and closer to the earth. (author)
Hybrid finite difference/finite element immersed boundary method.

Science.gov (United States)

E Griffith, Boyce; Luo, Xiaoyu

2017-12-01

The immersed boundary method is an approach to fluid-structure interaction that uses a Lagrangian description of the structural deformations, stresses, and forces along with an Eulerian description of the momentum, viscosity, and incompressibility of the fluid-structure system. The original immersed boundary methods described immersed elastic structures using systems of flexible fibers, and even now, most immersed boundary methods still require Lagrangian meshes that are finer than the Eulerian grid. This work introduces a coupling scheme for the immersed boundary method to link the Lagrangian and Eulerian variables that facilitates independent spatial discretizations for the structure and background grid. This approach uses a finite element discretization of the structure while retaining a finite difference scheme for the Eulerian variables. We apply this method to benchmark problems involving elastic, rigid, and actively contracting structures, including an idealized model of the left ventricle of the heart. Our tests include cases in which, for a fixed Eulerian grid spacing, coarser Lagrangian structural meshes yield discretization errors that are as much as several orders of magnitude smaller than errors obtained using finer structural meshes. The Lagrangian-Eulerian coupling approach developed in this work enables the effective use of these coarse structural meshes with the immersed boundary method. This work also contrasts two different weak forms of the equations, one of which is demonstrated to be more effective for the coarse structural discretizations facilitated by our coupling approach. © 2017 The Authors International Journal for Numerical Methods in Biomedical Engineering Published by John Wiley & Sons Ltd.
On the stability of boundary layers in gas mantle systems

International Nuclear Information System (INIS)

Ohlsson, D.

1978-10-01

In this thesis a systematic investigation of the stability properties of the partially ionized boundary regions of gas mantle systems for a large class of dissipative magneto-hydrodynamic modes is presented. In the partially ionized boundary regions of gas mantle systems several strong stabilizing mechanisms arise due to coupling between various dissipative effects in certain parameter regions. The presence of neutral gas strongly enhances the stabilizing effects in a dual fashion. First in an indirect way by cooling the edge region and second in a direct way by enhancing viscous and heat conduction effects. It has, however, to be pointed out that exceptions from this general picture may be found. The stabilizing influence of neutral gas on a large class of electrostatic as well as electromagnetic modes in the boundary regions of gas blanket systems is contrary to what has been found in low density weakly ionized plasmas. In these latter cases presence of neutral gas has even been found to be responsible for the onset of entirely new classes of instabilities. Thus there is no universal stabilizing or destabilizing effect associated with plasma-neutral gas interaction effects. (author)
Three dimensional boundary displacement due to stable ideal kink modes excited by external n = 2 magnetic perturbations

Science.gov (United States)

Willensdorfer, M.; Strumberger, E.; Suttrop, W.; Dunne, M.; Fischer, R.; Birkenmeier, G.; Brida, D.; Cavedon, M.; Denk, S. S.; Igochine, V.; Giannone, L.; Kirk, A.; Kirschner, J.; Medvedeva, A.; Odstrčil, T.; Ryan, D. A.; The ASDEX Upgrade Team; The EUROfusion MST1 Team

2017-11-01

In low-collisionality (ν\\star) scenarios exhibiting mitigation of edge localized mode (ELMs), stable ideal kink modes at the edge are excited by externally applied magnetic perturbation (MP)-fields. In ASDEX Upgrade these modes can cause three-dimensional (3D) boundary displacements up to the centimeter range. These displacements have been measured using toroidally localized high resolution diagnostics and rigidly rotating n=2 MP-fields with various applied poloidal mode spectra. These measurements are compared to non-linear 3D ideal magnetohydrodynamics (MHD) equilibria calculated by VMEC. Comprehensive comparisons have been conducted, which consider for instance plasma movements due to the position control system, attenuation due to internal conductors and changes in the edge pressure profiles. VMEC accurately reproduces the amplitude of the displacement and its dependencies on the applied poloidal mode spectra. Quantitative agreement is found around the low field side (LFS) midplane. The response at the plasma top is qualitatively compared. The measured and predicted displacements at the plasma top maximize when the applied spectra is optimized for ELM-mitigation. The predictions from the vacuum modeling generally fails to describe the displacement at the LFS midplane as well as at the plasma top. When the applied mode spectra is set to maximize the displacement, VMEC and the measurements clearly surpass the predictions from the vacuum modeling by a factor of four. Minor disagreements between VMEC and the measurements are discussed. This study underlines the importance of the stable ideal kink modes at the edge for the 3D boundary displacement in scenarios relevant for ELM-mitigation.
Edge subdivision and edge multisubdivision versus some domination related parameters in generalized corona graphs

Directory of Open Access Journals (Sweden)

Magda Dettlaff

2016-01-01

Full Text Available Given a graph \\(G=(V,E\\, the subdivision of an edge \\(e=uv\\in E(G\\ means the substitution of the edge \\(e\\ by a vertex \\(x\\ and the new edges \\(ux\\ and \\(xv\\. The domination subdivision number of a graph \\(G\\ is the minimum number of edges of \\(G\\ which must be subdivided (where each edge can be subdivided at most once in order to increase the domination number. Also, the domination multisubdivision number of \\(G\\ is the minimum number of subdivisions which must be done in one edge such that the domination number increases. Moreover, the concepts of paired domination and independent domination subdivision (respectively multisubdivision numbers are defined similarly. In this paper we study the domination, paired domination and independent domination (subdivision and multisubdivision numbers of the generalized corona graphs.
Numerical investigation of rarefaction effects in the vicinity of a sharp leading edge

Science.gov (United States)

Pan, Shaowu; Gao, Zhenxun; Lee, Chunhian

2014-12-01

This paper presents a study of rarefaction effect on hypersonic flow over a sharp leading edge. Both continuum approach and kinetic method: a widely spread commercial Computational Fluid Dynamics-Navior-Stokes-Fourier (CFD-NSF) software - Fluent together with a direct simulation Monte Carlo (DSMC) code developed by the authors are employed for simulation of transition regime with Knudsen number ranging from 0.005 to 0.2. It is found that Fluent can predict the wall fluxes in the case of hypersonic argon flow over the sharp leading edge for the lowest Kn case (Kn = 0.005) in current paper while for other cases it also has a good agreement with DSMC except at the location near the sharp leading edge. Among all of the wall fluxes, it is found that coefficient of pressure is the most sensitive to rarefaction while heat transfer is the least one. A parameter based on translational nonequilibrium and a cut-off value of 0.34 is proposed for continuum breakdown in this paper. The structure of entropy and velocity profile in boundary layer is analyzed. Also, it is found that the ratio of heat transfer coefficient to skin friction coefficient remains uniform along the surface for the four cases in this paper.
Edge preserving smoothing and segmentation of 4-D images via transversely isotropic scale-space processing and fingerprint analysis

International Nuclear Information System (INIS)

Reutter, Bryan W.; Algazi, V. Ralph; Gullberg, Grant T; Huesman, Ronald H.

2004-01-01

Enhancements are described for an approach that unifies edge preserving smoothing with segmentation of time sequences of volumetric images, based on differential edge detection at multiple spatial and temporal scales. Potential applications of these 4-D methods include segmentation of respiratory gated positron emission tomography (PET) transmission images to improve accuracy of attenuation correction for imaging heart and lung lesions, and segmentation of dynamic cardiac single photon emission computed tomography (SPECT) images to facilitate unbiased estimation of time-activity curves and kinetic parameters for left ventricular volumes of interest. Improved segmentation of lung surfaces in simulated respiratory gated cardiac PET transmission images is achieved with a 4-D edge detection operator composed of edge preserving 1-D operators applied in various spatial and temporal directions. Smoothing along the axis of a 1-D operator is driven by structure separation seen in the scale-space fingerprint, rather than by image contrast. Spurious noise structures are reduced with use of small-scale isotropic smoothing in directions transverse to the 1-D operator axis. Analytic expressions are obtained for directional derivatives of the smoothed, edge preserved image, and the expressions are used to compose a 4-D operator that detects edges as zero-crossings in the second derivative in the direction of the image intensity gradient. Additional improvement in segmentation is anticipated with use of multiscale transversely isotropic smoothing and a novel interpolation method that improves the behavior of the directional derivatives. The interpolation method is demonstrated on a simulated 1-D edge and incorporation of the method into the 4-D algorithm is described
Improved numerical grid generation techniques for the B2 edge plasma code

International Nuclear Information System (INIS)

Stotler, D.P.; Coster, D.P.

1992-06-01

Techniques used to generate grids for edge fluid codes such as B2 from numerically computed equilibria are discussed. Fully orthogonal, numerically derived grids closely resembling analytically prescribed meshes can be obtained. But, the details of the poloidal field can vary, yielding significantly different plasma parameters in the simulations. The magnitude of these differences is consistent with the predictions of an analytic model of the scrape-off layer. Both numerical and analytic grids are insensitive to changes in their defining parameters. Methods for implementing nonorthogonal boundaries in these meshes are also presented; they differ slightly from those required for fully orthogonal grids
Framework Application for Core Edge Transport Simulation (FACETS)

Energy Technology Data Exchange (ETDEWEB)

Krasheninnikov, Sergei; Pigarov, Alexander

2011-10-15

The FACETS (Framework Application for Core-Edge Transport Simulations) project of Scientific Discovery through Advanced Computing (SciDAC) Program was aimed at providing a high-fidelity whole-tokamak modeling for the U.S. magnetic fusion energy program and ITER through coupling separate components for each of the core region, edge region, and wall, with realistic plasma particles and power sources and turbulent transport simulation. The project also aimed at developing advanced numerical algorithms, efficient implicit coupling methods, and software tools utilizing the leadership class computing facilities under Advanced Scientific Computing Research (ASCR). The FACETS project was conducted by a multi-discipline, multi-institutional teams, the Lead PI was J.R. Cary (Tech-X Corp.). In the FACETS project, the Applied Plasma Theory Group at the MAE Department of UCSD developed the Wall and Plasma-Surface Interaction (WALLPSI) module, performed its validation against experimental data, and integrated it into the developed framework. WALLPSI is a one-dimensional, coarse grained, reaction/advection/diffusion code applied to each material boundary cell in the common modeling domain for a tokamak. It incorporates an advanced model for plasma particle transport and retention in the solid matter of plasma facing components, simulation of plasma heat power load handling, calculation of erosion/deposition, and simulation of synergistic effects in strong plasma-wall coupling.
Twin and grain boundary in InP: A synchrotron radiation study

International Nuclear Information System (INIS)

Han, Y.; Liu, X.; Jiao, J.; Lin, L.; Jiang, J.; Wang, Z.; Tian, Y.

1998-01-01

Experimentally observed X-ray reflectivity curves show bi-crystal(twin) characteristics. The study revealed that there was defect segregation at the twin boundary. Stress was relaxed at the edge of the boundary. Relaxation of the stress resulted in formation of twin and other defects. As a result of formation of such defects, a defect-free and stress-free zone or low defect density and small stress zone is created around the defects. So a twin model was proposed to explain the experimental results. Stress(mainly thermal stress), chemical stoichiometry deviation and impurities nonhomogeneous distributions are the key factors that cause twins in LEC InP crystal growth. Twins on (111) face in LEC InP crystal were studied. Experimental evidence of above mentioned twin model and suggestions on how to get twin-free LEC InP single crystals will be discussed
Vision-based weld pool boundary extraction and width measurement during keyhole fiber laser welding

Science.gov (United States)

Luo, Masiyang; Shin, Yung C.

2015-01-01

In keyhole fiber laser welding processes, the weld pool behavior is essential to determining welding quality. To better observe and control the welding process, the accurate extraction of the weld pool boundary as well as the width is required. This work presents a weld pool edge detection technique based on an off axial green illumination laser and a coaxial image capturing system that consists of a CMOS camera and optic filters. According to the difference of image quality, a complete developed edge detection algorithm is proposed based on the local maximum gradient of greyness searching approach and linear interpolation. The extracted weld pool geometry and the width are validated by the actual welding width measurement and predictions by a numerical multi-phase model.
Numerical study on effect of boundary layer trips on aerodynamic performance of E216 airfoil

Directory of Open Access Journals (Sweden)

B.K. Sreejith

2018-02-01

Full Text Available Simulation is carried out to find the performance of airfoil E216 using Transition γ-Reθ model at Reynolds number of 100,000. Flow behaviour and effect of angle of attack (AOA on laminar separation bubble (LSB formation are examined. The results are validated with wind tunnel experimental results. LSB formation is clearly spotted in the velocity vector plot and coefficient of pressure distribution over airfoil. LSB moved upstream towards the leading edge with increase in AOA. Effect of boundary layer trip on LSB formation over the airfoil and performance of airfoil are studied. Two different trip locations, 17% of chord and 10% of chord from leading edge, and different trip heights (0.3 mm, 0.5 mm, 0.7 mm, 1 mm are investigated in this study. Results showed that boundary layer trip could eliminate LSB partially or completely and improve aerodynamic performance of the airfoil. Maximum improvement in drag by 15.48% and lift to drag ratio by 21.62% are obtained at angle of attack of 60. In all the cases, improvement in performance is observed only up to trip height of 0.5 mm.
Effects of Collisionality on the Nonlinear Characteristics of Boundary Turbulence and Blob/hole Transport in Tokamak Plasmas

Energy Technology Data Exchange (ETDEWEB)

Li, J.; Yasuaki, K., E-mail: lijq@energy.kyoto-u.ac.jp [Kyoto University, Kyoto (Japan); Cheng, J.; Longwen, Y.; Jiaqi, D. [Southwestern Institute of Physics, Chengdu (China)

2012-09-15

Full text: Blob/hole dynamics near tokamak separatrix is of striking importance in determining the boundary transport. Based on simulations using an extended 2-region (edge/SOL) fluid model, we found that blob/hole dynamics are sensitively influenced by the plasma collisionality, i.e., ion-electron and ion-neutral collisions. Namely, the holes are enhanced in highly collisional edge whereas the blobs are weakened at the SOL, causing larger particle convection. These blob/hole dynamics are closely correlated with potential dipoles. The trends are experimentally evidenced on the HL-2A tokamak. Moreover, as the neutral-ion collision increases, the blobs at the SOL tend to develop into streamers propagating outwards with reduced amplitude while the holes inwards are suppressed, showing a key role in nonlinear structure regulation and resultant transport suppression. Results suggest that adjusting the plasma collisionality by fueling, e.g., gas puffing, could serve as a method to nonlinearly select turbulent structures, i.e., blobs, holes or streamers, to access the control of boundary transport. (author)
Manipulation of Turbulent Boundary Layers Using Synthetic Jets

Science.gov (United States)

Berger, Zachary; Gomit, Guillaume; Lavoie, Philippe; Ganapathisubramani, Bharath

2015-11-01

This work focuses on the application of active flow control, in the form of synthetic jet actuators, of turbulent boundary layers. An array of 2 synthetic jets are oriented in the spanwise direction and located approximately 2.7 meters downstream from the leading edge of a flat plate. Actuation is applied perpendicular to the surface of the flat plate with varying blowing ratios and reduced frequencies (open-loop). Two-component large window particle image velocimetry (PIV) was performed at the University of Southampton, in the streamwise-wall-normal plane. Complementary stereo PIV measurements were performed at the University of Toronto Institute for Aerospace Studies (UTIAS), in the spanwise-wall-normal plane. The freestream Reynolds number is 3x104, based on the boundary layer thickness. The skin friction Reynolds number is 1,200 based on the skin friction velocity. The experiments at Southampton allow for the observation of the control effects as the flow propagates downstream. The experiments at UTIAS allow for the observation of the streamwise vorticity induced from the actuation. Overall the two experiments provide a 3D representation of the flow field with respect to actuation effects. The current work focuses on the comparison of the two experiments, as well as the effects of varying blowing ratios and reduced frequencies on the turbulent boundary layer. Funded Supported by Airbus.
Mortality after percutaneous edge-to-edge mitral valve repair: a contemporary review.

Science.gov (United States)

Kortlandt, Friso A; de Beenhouwer, Thomas; Swaans, Martin J; Post, Marco C; van der Heyden, Jan A S; Eefting, Frank D; Rensing, Benno J W M

2016-04-01

Percutaneous edge-to-edge mitral valve (MV) repair is a relatively new treatment option for mitral regurgitation (MR). After the feasibility and safety having been proved in low-surgical-risk patients, the use of this procedure has shifted more to the treatment of high-risk patients. With the absence of randomized controlled trials (RCT) for this particular subgroup, observational studies try to add evidence to the safety aspect of this procedure. These also provide short- and mid-term mortality figures. Several mortality predictors have been identified, which may help the optimal selection of patients who will benefit most from this technique. In this article we provide an overview of the literature about mortality and its predictors in patients treated with the percutaneous edge-to-edge device.
Fluid simulations of ∇Te-driven turbulence and transport in boundary plasmas

International Nuclear Information System (INIS)

Xu, X.Q.

1992-01-01

It is clear that the edge plasma plays a crucial role in global tokamak confinement. This paper is a report on simulations of a new drift wave type instability driven by the electron temperature gradient in tokamak scrapeoff-layers (SOL). A 2d fluid code has been developed in order to explore the anomalous transport in the boundary plasmas. The simulation consists of a set of fluid equations for the vorticity ∇ perpendicular 2 φ, the electron density n c and the temperature T c in a shearless plasma slab confined by a uniform, straight magnetic field B z with two divertor (or limiter) plates intercepting the magnetic field. The model has two regions separated by a magnetic separatrix: in the edge region inside the separatrix, the model is periodic along the magnetic field while in the SOL region outside the separatrix, the magnetic field is taken to be of finite length with model boundary conditions at diverter plates. The simulation results show that the observed linear instability agrees well with theory, and that a saturated state of turbulence is reached. In saturated turbulence, clear evidence of the expected long-wavelength mode penetration into the edge is seen, an inverse cascade of wave energy is observed. The simulation results also show that amplitudes of potential and the electron temperature fluctuations are somewhat above and the heat flux are somewhat below those of the simplest mixing-length estimates, and furthermore the large-scale radial structures of fluctuation quantities indicate that the cross-field transport is not diffusive. After saturation, the electron density and temperature profiles are flattened. A self-consistent simulation to determine the microturbulent SOL electron temperature profile has been done, the results of which reasonably agree with the experimental measurements
Adobe Edge Preview 3

CERN Document Server

Grover, Chris

2011-01-01

Want to use an Adobe tool to design animated web graphics that work on iPhone and iPad? You've come to the right book. Adobe Edge Preview 3: The Missing Manual shows you how to build HTML5 graphics using simple visual tools. No programming experience? No problem. Adobe Edge writes the underlying code for you. With this eBook, you'll be designing great-looking web elements in no time. Get to know the workspace. Learn how Adobe Edge Preview 3 performs its magic.Create and import graphics. Make drawings with Edge's tools, or use art you designed in other programs.Work with text. Build menus, lab

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