1,697 research outputs found
Raman spectroscopy, a non-destructive solution to the study of glass and its alteration
This paper presents the potential of Raman spectroscopy, a non-destructive technique which can be applied in-situ, for the analyses of glass and their alteration. Recent analytical developments are summarised for different glass composition and practical examples are given. The paper describes how to extract compositional information from the glass, first based on the spectra profile to distinguish rapidly alkali silicate from alkaline-earth alkali silicate and lead alkali silicate glass, then using the spectral decomposition and correlations to extract quantitative data. For alkali silicate glasses, that are most prone to alteration, the spectral characteristics are described to interpret the alteration process (selective leaching or dissolution of the glass) from the Raman spectra of the altered glass. These developments have greatly widened the potential of the technique and supplement well its ability to measure the thickness of the altered layer and identify the crystalline deposits
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SERVice Oriented Intelligent Value Adding nEtwork for Clothing-SMEs embarking in Mass-Customisation [as a result of the Automatic knitting Sites pilot, Task D6.2a]. CORDIS.
Executive Summary: This report describes the outcomes of research and development work done by IFTH (France) and Nottingham Trent University (UK) to develop and evaluate the procedures for a business model to produce commercially customised fully-fashioned knitwear. It builds on the initial work done by Unicatum, RWTH and Hohenstein Institute (Germany). The purpose was to demonstrate the commercial potential for on-demand, localised manufacturing of up-market fashion products using new technology. The target market was upper-middle market knitwear for ladies, typical products being a jumper, cardigan or dress. As with the rest of the SERVIVE project, customisation has been assumed to be linked to style advice. Thus part of the overall product and consumer experience is the initial process of co-design. This is partly illustrated in the video of the demonstration [see http://www.youtube.com/watch?v=WIodKyciJAM]. However as this could vary according to each retailer (e.g. web-based or personal style advisor, product category, etc.), this aspect is better covered in other SERVIVE project deliverables. The key technology assumed in the micro-factory is one or more whole-garment 3D knitting machines. It is recognised that this can be an option with circular knitting (e.g. Santoni), but in this instance the focus is on the multiple flat-bed technology such as is available from Stoll and Shima Seiki
Thermo-mechanical behaviour of a compacted swelling clay
Compacted unsaturated swelling clay is often considered as a possible buffer
material for deep nuclear waste disposal. An isotropic cell permitting
simultaneous control of suction, temperature and pressure was used to study the
thermo-mechanical behaviour of this clay. Tests were performed at total
suctions ranging from 9 to 110 MPa, temperature from 25 to 80 degrees C,
isotropic pressure from 0.1 to 60 MPa. It was observed that heating at constant
suction and pressure induces either swelling or contraction. The results from
compression tests at constant suction and temperature evidenced that at lower
suction, the yield pressure was lower, the elastic compressibility parameter
and the plastic compressibility parameter were higher. On the other hand, at a
similar suction, the yield pressure was slightly influenced by the temperature;
and the compressibility parameters were insensitive to temperature changes. The
thermal hardening phenomenon was equally evidenced by following a
thermo-mechanical path of loading-heating-cooling-reloading
The Green Souvenir Industry of Kerala – A Comprehensive Analysis
Handicrafts and souvenirs have a long and glorious tradition behind them. They represent the culture of the people and from a great heritage of art. Souvenirs are a manifestation of the creative impulse of people. The specialty of the handicraft is that it reflects the craftsmanship of each and every part of the country. Souvenirs always remind a traveller of a particular place that it was purchased from. Souvenir trade improves the local economy and even serves as a brand image or icon of the destination visited by tourists while providing easy visibility. Souvenirs also help in the word of mouth marketing of a destination. The souvenir trade worldwide is part of a rich handicraft tradition that evolved over the years. India has a diversity of souvenirs, and so does Kerala. The uniqueness of Kerala isits abundance of plant or natural fibre-based souvenirs. But, little research has been done on the process of production or the potential it provides in promoting tourism. This study is an attempt to look into the problems and prospects of plant or natural fibre based - ‘green souvenirs’ of Kerala and to offer suggestions for improving its market
Laminar supersonic sphere wake unstable bifurcations
The laminar sphere unstable bifurcations are sought at a Mach number of M∞ = 1.2. Global stability performed on steady axisymmetric base flows determines the regular bifurcation critical Reynolds number at Rereg cr = 650, identifying a steady planar-symmetric mode to cause the loss of the wake axisymmetry. When global stability is performed on steady planar-symmetric base flows, a Hopf bifurcation is found at ReHopf cr = 875 and an oscillatory planar-symmetric mode is temporally amplified. Despite some differences due to highly compressible effects, the supersonic unstable bifurcations present remarkably similar characteristics to their incompressible counterparts, indicating a robust laminar wake behavior over a large range of flow speeds. A new bifurcation for steady planar-symmetric base flow solutions is found above Re > 1000, caused by an anti-symmetric mode consisting of a 90○ rotation of the dominant mode. To investigate this reflectional symmetry breaking bifurcation in the nonlinear framework, unsteady nonlinear calculations are carried out up to Re = 1300 and dynamic mode decomposition (DMD) based on the combination of input data low-dimensionalization and compressive sensing is used. While the DMD analysis confirms dominance and correspondence in terms of modal spatial distribution with respect to the global stability mode responsible for the Hopf bifurcation, no reflectional symmetry breaking DMD modes were found, asserting that the reflectional symmetry breaking instability is not observable in the nonlinear dynamics. The increased complexity of the wake dynamics at Re = 1300 can be instead explained by nonlinear interactions that suggest the low-frequency unsteadiness to be linked to the destabilization of the hairpin vortex shedding limit cycle.CNE
Numerical investigation of the interaction between laminar to turbulent transition and the wake of an airfoil
The objective of this work is to investigate numerically the different physical mechanisms of the transition to turbulence of a separated boundary-layer flow over an airfoil at low angle of attack. In this study, the spectral elements code Nek5000 is used to simulate the flow over a SD7003 wing section at an angle of attack of α = 4 ◦ . Several laminar cases are first studied from Re = 2000 to Re = 10000, and a gradual increase of the Reynolds number is then performed in order to investigate one transitional case at Re = 20000. Computations are compared with measurements where the instability mechanisms in the separated zone and near wake zone have been analyzed. The mechanism of transition is investigated, where the DMD (Dynamic Mode Decomposition) is used in order to extract the main physical modes of the flow and to highlight the interaction between the transition and the wake flow. The results suggest that the transition process appears to be physically independent of the wake flow, while the LSB shedding process is locked-in with the von Kármán instability and acts as a sub-harmonic
A high-order Godunov scheme for global 3D MHD accretion disks simulations. I. The linear growth regime of the magneto-rotational instability
We employ the PLUTO code for computational astrophysics to assess and compare
the validity of different numerical algorithms on simulations of the
magneto-rotational instability in 3D accretion disks. In particular we stress
on the importance of using a consistent upwind reconstruction of the
electro-motive force (EMF) when using the constrained transport (CT) method to
avoid the onset of numerical instabilities. We show that the electro-motive
force (EMF) reconstruction in the classical constrained transport (CT) method
for Godunov schemes drives a numerical instability. The well-studied linear
growth of magneto-rotational instability (MRI) is used as a benchmark for an
inter-code comparison of PLUTO and ZeusMP. We reproduce the analytical results
for linear MRI growth in 3D global MHD simulations and present a robust and
accurate Godunov code which can be used for 3D accretion disk simulations in
curvilinear coordinate systems
Expansion of elevational range in a forest pest: Can parasitoids track their hosts?
We are thankful to Karim Senhadji and Ramon Ruiz-Puche for their help during the field work, and to Sara Garcia Morato for her contribution to quantifying rates of parasitism in PPM clutches at the laboratory. Two anonymous referees contributed to improve the manuscript. This study was supported by projects PROPINOL (PN22/2008), GESBOME (P06-RNM-1890) from Junta de Andalucia, REMEDINAL TE-CM (S2018/EMT-4338) from Comunidad de Madrid, ADAPTAMED (LIFE14 CCA/ES/000612) from LIFE program, and GILES (PCIN-2016-150) from the ERANET-LAC H2020 Programme.Gradients in elevation impose changes in environmental conditions, which in turn modulate species distribution and abundance as well as the interactions they maintain. Along the gradient, interacting species (e.g., predators, parasitoids) can respond to changes in different ways. This study aims to investigate how egg parasitism of a forest pest, the pine processionary moth (PPM), Thaumetopoea pityocampa, vary along an elevational gradient (190-2000 m.a.s.l.) in a mountain range of SE Spain, including areas of recent elevational expansion, for a seven years period (2008-2014). We used generalized linear mixed models to ascertain the effect of both elevation and the winter North Atlantic Oscillation (NAO) index (a proxy of interannual climatic conditions) on the rate of parasitism, and the occurrence probabilities of two parasitoid species: a PPM specialist and a generalist species. Since four pine species are stratified along the elevational gradient, we repeated all the analyses separately for lowlands (190-1300 m. a.s.l.) and uplands (1350-2000 m. a.s.l.). Results showed a decrease in both parasitism rate and probability of occurrence of the two main parasitoid species with elevation, although decline was more severe for the specialist species. The effect of elevation was more conspicuous and intense in uplands than in lowlands. Positive NAO winter values, associated with cold and dry winters, reduced the rate of parasitism and the probability of occurrence of the two main parasitoid species-but particularly for the generalist species-as elevation increases. In a context of climate warming, it is crucial to mitigate PPM elevational and latitudinal expansion. Increasing tree diversity at the PPM expansion areas may favor the establishment of parasitoids, which could contribute to synchronizing host- parasitoid interactions and minimize the risk of PPM outbreaks.Junta de Andalucia
PN22/2008REMEDINAL TE-CM from Comunidad de Madrid
S2018/EMT-4338ADAPTAMED from LIFE program
LIFE14 CCA/ES/000612GILES from the ERANET-LAC H2020 Programme
PCIN-2016-150Junta de Andalucia
P06-RNM-189
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