21,433 research outputs found

    DRESS-down: /ε/-lowering in apparent time in a rural Scottish community

    Get PDF
    This paper presents a sociophonetic investigation of /ɛ/-lowering in apparent time. The data come from 24 speakers, across three generations from Buckie, northeast Scotland (12 males, 12 females). Acoustic analysis of the DRESS-vowel reveals that it is lowering in apparent time. Inspection of the constraints reveals an interaction of internal and external constraints. Analysis of the phonetic context revealed that following-l promoted DRESS lowering. However, this conditioning was only significant for the young females who were shown to be leading the change. The results presented here are related to broader phonological characteristics of the Buckie dialect as well as ongoing changes in a number of different English varieties

    DRESS-Down: /ε/-lowering in Apparent Tme in a Rural Scottish Community

    Get PDF
    This paper presents a sociophonetic investigation of /ɛ/-lowering in apparent time. The data come from 24 speakers, across three generations from Buckie, northeast Scotland (12 males, 12 females). Acoustic analysis of the DRESS-vowel reveals that it is lowering in apparent time. Inspection of the constraints reveals an interaction of internal and external constraints. Analysis of the phonetic context revealed that following-l promoted DRESS lowering. However, this conditioning was only significant for the young females who were shown to be leading the change. The results presented here are related to broader phonological characteristics of the Buckie dialect as well as ongoing changes in a number of different English varietie

    Development of non-destructive methodology using ATR-FTIR with PCA to differentiate between historical Pacific barkcloth

    Get PDF
    Barkcloths, non-woven textiles originating from the Pacific Islands, form part of many museum collections and date back to the 18th and 19th centuries. The ability to determine different plant species which have been used for producing barkcloth is required by art historians to help understand the origin and use of the cloths and by conservators for whom the species type may have an impact on textile durability, deterioration and hence conservation. However, to date the development of a non-destructive, robust analytical technique has been elusive. This article describes the use of Fourier transform infrared spectroscopy with attenuated total reflection (ATR-FTIR) and principal component analysis (PCA) todifferentiation between historic barkcloths. Three distinct groups of historic cloths were identified using PCA of the FTIR region between 1200 and 1600 cm−1 where molecular vibrations associated with tannins and lignins are dominant. Analysis of contemporary cloths only identified Pipturus albidus cloth as different and highlighted the difficulties around producing a representative textile sample to mimic the historic cloths. While the methodology does not itself identify species, the use of historically well-provenanced samples allows cloths showing similarities to group together and is a significant aid to identification

    Low-dimensional models for turbulent plane Couette flow in a minimal flow unit

    Get PDF
    We model turbulent plane Couette flow in the minimal flow unit (MFU) – a domain whose spanwise and streamwise extent is just sufficient to maintain turbulence – by expanding the velocity field as a sum of optimal modes calculated via proper orthogonal decomposition from numerical data. Ordinary differential equations are obtained by Galerkin projection of the Navier–Stokes equations onto these modes. We first consider a 6-mode (11-dimensional) model and study the effects of including losses to neglected modes. Ignoring these, the model reproduces turbulent statistics acceptably, but fails to reproduce dynamics; including them, we find a stable periodic orbit that captures the regeneration cycle dynamics and agrees well with direct numerical simulations. However, restriction to as few as six modes artificially constrains the relative magnitudes of streamwise vortices and streaks and so cannot reproduce stability of the laminar state or properly account for bifurcations to turbulence as Reynolds number increases. To address this issue, we develop a second class of models based on ‘uncoupled’ eigenfunctions that allow independence among streamwise and cross-stream velocity components. A 9-mode (31-dimensional) model produces bifurcation diagrams for steady and periodic states in qualitative agreement with numerical Navier–Stokes solutions, while preserving the regeneration cycle dynamics. Together, the models provide empirical evidence that the ‘backbone’ for MFU turbulence is a periodic orbit, and support the roll–streak–breakdown–roll reformation picture of shear-driven turbulence

    Monitoring the deflection of a membrane using direct UV written planar Bragg gratings

    No full text
    A thin (~100 µm thick) silica-on-silicon square membrane (10 mm x 10 mm) has been fabricated and its deflection monitored through a 100 Bragg grating array defined within the membrane

    Responding to accents after experiencing interactive or mediated speech

    Get PDF
    Very little known is about how speakers learn about and/or respond to speech experienced without the possibility for interaction. This paper reports an experiment which considers the effects of two kinds of exposure to speech (interactive or non-interactive mediated) on Scottish English speakers’ responses to another accent (Southern British English), for two processing tasks, phonological awareness and speech production. Only marginal group effects are found according to exposure type. The main findings show a difference between subjects according to exposure type before exposure, and individual shifts in responses to speech according to exposure type

    Confirming what we know: Understanding questionable research practices in intro physics labs

    Full text link
    Many institutions are changing the focus of their introductory physics labs from verifying physics content towards teaching students about the skills and nature of science. As instruction shifts, so too will the ways students approach and behave in the labs. In this study, we evaluated students' lab notes from an early activity in an experimentation-focused lab course. We found that about 30% of student groups (out of 107 groups at three institutions) recorded questionable research practices in their lab notes, such as subjective interpretations of results or manipulating equipment and data. The large majority of these practices were associated with confirmatory goals, which we suspect stem from students' prior exposure to verification labs. We propose ways for experimentation-focused labs to better engage students in the responsible conduct of research and authentic scientific practice.Comment: 4 pages, 4 figure
    corecore