413 research outputs found
Note sur les premiers essais de capture du crabe profond Geryon quinquedens en Côte d'Ivoire
First experiments to trap the deep sea red crab Geryon quinquedens off Côte d'Ivoire have had good success. The yields obtained are similar to those observed off the northeastern coast of the United States and off Angola, where commercial fisheries have been developed for some years
Drying and Heating Modelling of Granular Flow: Application to the Mix-Asphalt Processes
Concrete asphalt is a hydrocarbon material that includes a mix of mineral components along with a bituminous
binder. Prior to mixing, its production protocol requires drying and heating the aggregates. Generally performed in a
rotary drum, these drying and heating steps within mix asphalt processes have never been studied from a physical
perspective. We are thus proposing in the present paper to analyze the drying and heating mechanisms when granular
materials and hot gases are involved in a co-current flow. This process step accounts for a large proportion of the
overall energy consumed during hot-mix asphalt manufacturing. In the present context, the high energy cost
associated with this step has encouraged developing new strategies specifically for the drying process. Applying new
asphalt techniques so that an amount of moisture can be preserved in the asphalt concrete appears fundamental to
such new strategies. This low-energy asphalt, also referred to as the "warm technique", depends heavily on a relevant
prediction of the actual moisture content inside asphalt concrete during the mixing step. The purpose of this paper is
to present a physical model dedicated to the evolution in temperature and moisture of granular solids throughout the
drying and heating steps carried out inside a rotary drum. An initial experimental campaign to visualize inside a drum
at the pilot scale (i.e. 1/3 scale) has been carried out in order to describe the granular flow and establish the necessary
physical assumptions for the drying and heating model. Energy and mass balance equations are solved by
implementing an adequate heat and mass transfer coupling, yielding a 1D model from several parameters that in turn
drives the physical modeling steps. Moreover, model results will be analyzed and compared to several measurements
performed in an actual asphalt mix plant at the industrial scale (i.e. full scale)
Exploring a Place-Based Approach to Materials Design: Harakeke Nonwovens in Aotearoa New Zealand
As the interdisciplinary field of materials design expands, pressing environmental, social and economic crises mean that the impacts of materials are more clearly perceived (Drazin 2015). This presents a challenge to activate materials towards positive change. Design practices that are relational, place based and deeply attuned to justice and the Earth are needed (Escobar 2017). What might such practices look like within the field of materials design? And how might they be informed by textiles practice? To address these questions, this paper presents and reflects upon a recent study into the development of harakeke (Phormium Tenax/New Zealand Flax) based nonwovens. The aim of the study was to support the re-establishment of harakeke based industry in Aotearoa New Zealand, which recent research suggests could address a range of environmental, social and economic problems specific to the region (McGruddy 2006). The approach taken drew on notions of place-based design and textile thinking, and was underpinned by a collaboration between university based design researchers, an agricultural and a forestry/ biomaterials research institute, an independent designer and an expert in traditional harakeke weaving. An initial review of materials design, research and developments that are predicated on regionally specific resources and knowledge was undertaken. Processing trials were conducted that brought together knowledge from indigenous harakeke weaving practice, fine art practices, industrially based fibre processing techniques and biopolymer processing. The resulting new materials were qualitatively evaluated using emergent models of experiential characterization (Camere and Karana 2018), which showed potential for the materials to be developed towards applications including architectural surfaces and packaging
Investigation of the thermal stability of Mg/Co periodic multilayers for EUV applications
We present the results of the characterization of Mg/Co periodic multilayers
and their thermal stability for the EUV range. The annealing study is performed
up to a temperature of 400\degree C. Images obtained by scanning transmission
electron microscopy and electron energy loss spectroscopy clearly show the good
quality of the multilayer structure. The measurements of the EUV reflectivity
around 25 nm (~49 eV) indicate that the reflectivity decreases when the
annealing temperature increases above 300\degreeC. X-ray emission spectroscopy
is performed to determine the chemical state of the Mg atoms within the Mg/Co
multilayer. Nuclear magnetic resonance used to determine the chemical state of
the Co atoms and scanning electron microscopy images of cross sections of the
Mg/Co multilayers reveal changes in the morphology of the stack from an
annealing temperature of 305\degreee;C. This explains the observed reflectivity
loss.Comment: Published in Applied Physics A: Materials Science \& Processing
Published at
http://www.springerlink.com.chimie.gate.inist.fr/content/6v396j6m56771r61/ 21
page
Non-Dipolar Electron Angular Distributions from Fixed-in-Space Molecules
The first indication of nondipole effects in the azimuthal dependence of photoelectron angular distributions emitted from fixed-in-space molecules is demonstrated in N2. Comparison of the results with angular distributions observed for randomly oriented molecules and theoretical derivations for the nondipole correction first order in photon momentum suggests that higher orders will be needed to describe distributions measured in the molecular frame
Anterolateral ligament reconstruction does not delay functional recovery, rehabilitation, and return to sport after anterior cruciate ligament reconstruction. A matched-pair analysis from the SANTI (Scientific ACL Network International) Study Group
Purpose: To determine whether the addition of an anterolateral ligament reconstruction (ALLR) resulted in delayed functional recovery (based on the Knee Santy Athletic Return to Sport [K-STARTS] score) at 6 months after anterior cruciate ligament reconstruction (ACLR). Methods: A retrospective analysis of prospectively collected data from consecutive pa- tients who underwent an ACLR between September 2017 and December 2020 was conducted. Patients who received an isolated hamstring autograft (isolated ACLR group) were propensity matched in a 1:1 ratio to patients who received a hamstring autograft ACLR combined with an ALLR (ACLR-ALLR group). Outcome measures included the Tegner Activity Scale and the K-STARTS testda validated composite return-to-sports test (including the Anterior Cruciate LigamenteReturn to Sport After Injury scale, Qualitative Assessment of Single-Leg Landing tool, limb symmetry index, and ability to change direction using the Modified Illinois Change of Direction Test). Results: The study included 111 matched pairs. At 6 months postoperatively, there were no significant differences between groups in the overall K-STARTS score (65.4 for isolated ACLR vs 61.2 for ACLR-ALLR, P 1⁄4 .087) or the Tegner Activity Scale score (3.7 for isolated ACLR vs 3.8 for ACLR-ALLR, P 1⁄4 .45). In addition, an evaluation of the subscales of the K-STARTS score revealed no disadvantage across the domains of neuromuscular control, limb symmetry index, agility, or psychological readiness to return to sport when an ALLR was performed. Conclusions: The addition of ALLR at the time of ACLR does not delay functional recovery. Spe- cifically, at 6 months postoperatively, there was no disadvantage in patients undergoing ALLR-ACLR, when compared with those undergoing isolated ACLR, with respect to neuromuscular control, limb symmetry indices (hop tests), agility, or psychological readiness to return to sport
Introduction of Zr in nanometric periodic Mg/Co multilayers
We study the introduction of a third material, namely Zr, within a nanometric
periodic Mg/Co structure designed to work as optical component in the extreme
UV (EUV) spectral range. Mg/Co, Mg/Zr/Co, Mg/Co/Zr and Mg/Zr/Co/Zr multilayers
are designed, then characterized in terms of structural quality and optical
performances through X-ray and EUV reflectometry measurements respectively. For
the Mg/Co/Zr structure, the reflectance value is equal to 50% at 25.1 nm and
45deg of grazing incidence and reaches 51.3% upon annealing at 200deg C.
Measured EUV reflectivity values of tri-layered systems are discussed in terms
of material order within a period and compared to the predictions of the
theoretical model of Larruquert. Possible applications are pointed out.Comment: 19 page
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