1,063 research outputs found
Nanotexture influence of BaTiO3 particles on piezoelectric behaviour of PA 11/BaTiO3 nanocomposites
The piezoelectric activity of a hybrid ferroelectric nanocomposite, i.e. polyamide 11/barium titanate (BT),
has been investigated for different loadings of BT particles. The BT volume fraction (/) was ranging from
0.024 to 0.4 with a particle size of 50, 100, 300 and 700 nm. The influence of polarization mode on the
piezoelectric behaviour has been studied. The magnitude of the poling field used in this study is in the
same order of magnitude of the one used for bulk BT i.e. significantly lower than for piezoelectric polymers.
The optimum piezoelectric coefficient is reached when the amorphous phase of the polymeric
matrix is in the liquid state i.e. for a polarization temperature higher than the glass transition and for time
constant allowing macromolecular mobility. The composite piezoelectric activity decreases for particles
size lower than 300 nm due to the loss of the tetragonal phase. The nanotexture of these particles has
been investigated by transmission electron microscopy (TEM) and high-resolution TEM. A core shell
structure has been observed. An increase of the longitudinal piezoelectric strain coefficient d33 with
the raising of BT volume fraction was shown. Contrary to inorganic piezoelectric ceramics, the dielectric
permittivity of hybrid composites remains moderate; therefore it allows the piezoelectric voltage coefficient
of composites to be higher than ceramics
Dielectric relaxations and ferroelectric behaviour of even–odd polyamide PA 6,9
Thermo Stimulated Current (TSC) combined with Dynamic Dielectric Spectroscopy (DDS) have been applied to the investigation of dielectric relaxation modes of an even–odd Polyamide PA 6,9. The correlation between results obtained by both methods allows us to describe precisely the molecular mobility. At high temperature, the various dielectric relaxation phenomena are separated by applying the dielectric modulus formalism. The comparison between the activation enthalpy values obtained by DDS and TSC leads to the assignment of the so-called α mode to cooperative movements of polymeric sequences. Molecular mobility of PA 6,9 is compared with the one of PA 11. The piezoelectric activity of PA 6,9 is shown and analyzed
Early major maxillary deformation after cerebral anoxia in an adult: Case report and literature review
Market Power and Collusion on Interconnection Phone Market in Tunisia : What Lessons from International Experiences
We try in this paper to characterize the state of mobile phone market in Tunisia. Our study is based on a survey of foreign experience (Europe) in detecting collusive behavior and a comparison of the critical threshold of collusion between operators in developing countries like Tunisia. The market power is estimated based on the work of Parker Roller (1997) and the assumption of "Balanced Calling Pattern". We use then the model of Friedman (1971) to compare the critical threshold of collusion. We show that the "conduct parameter" measuring the intensity of competition is not null during the period 1993-2011. Results show also that collusion is easier on the Tunisian market that on the Algerian, Jordanian, or Moroccan one
Microstructural Characterization of Graphite Spheroids in Ductile Iron
The present work brings new insights by transmission electron microscopy allowing disregarding or supporting some of the models proposed for spheroidal growth of graphite in cast irons. Nodules consist of sectors made of graphite plates elongated along a hai direction and stack on each other with their c axis aligned with the radial direction. These plates are the elementary units for spheroidal growth and a calculation supports the idea that new units continuously nucleate at the ledge between sectors
Inner Space Preserving Generative Pose Machine
Image-based generative methods, such as generative adversarial networks
(GANs) have already been able to generate realistic images with much context
control, specially when they are conditioned. However, most successful
frameworks share a common procedure which performs an image-to-image
translation with pose of figures in the image untouched. When the objective is
reposing a figure in an image while preserving the rest of the image, the
state-of-the-art mainly assumes a single rigid body with simple background and
limited pose shift, which can hardly be extended to the images under normal
settings. In this paper, we introduce an image "inner space" preserving model
that assigns an interpretable low-dimensional pose descriptor (LDPD) to an
articulated figure in the image. Figure reposing is then generated by passing
the LDPD and the original image through multi-stage augmented hourglass
networks in a conditional GAN structure, called inner space preserving
generative pose machine (ISP-GPM). We evaluated ISP-GPM on reposing human
figures, which are highly articulated with versatile variations. Test of a
state-of-the-art pose estimator on our reposed dataset gave an accuracy over
80% on PCK0.5 metric. The results also elucidated that our ISP-GPM is able to
preserve the background with high accuracy while reasonably recovering the area
blocked by the figure to be reposed.Comment: http://www.northeastern.edu/ostadabbas/2018/07/23/inner-space-preserving-generative-pose-machine
Desarrollo del aparato digestivo en pollos Campero INTA alimentados con poroto mucuna (Stizolobium deeringianum)
Las leguminosas tropicales se utilizan en los sistemas de producción alternativos para la alimentación de aves. En el presente trabajo se evaluó el efecto de la incorporación de harina de poroto mucuna (Stizolobium deeringianum) en el alimento terminador, sobre el desarrollo del aparato digestivo en pollos Campero INTA. La dieta control se elaboró en base a maíz, soja y una premezcla de vitaminas y minerales; en la dieta de prueba el poroto mucuna reemplazó parcialmente a la harina de soja. El análisis comparativo se realizó mediante ANOVA en un arreglo factorial, operando el sexo y tipo de alimento como efectos principales. No se constataron interacciones significativas entre los distintos niveles de ambos factores para las variables dependientes analizadas. Se constataron diferencias significativas para peso relativo del tracto gastrointestinal con valores de 6,62±0,62 y 7,33±0,59% para las dietas control y mucuna respectivamente. El peso relativo del estómago muscular registró diferencias estadísticas significativas con valores de 2,56±0,45 y 3,06±0,46% para las dietas control y mucuna respectivamente. Se demostraron correlaciones positivas y significativas entre el peso relativo del tracto gastrointestinal y del estómago glandular (r=0,82; p=0,01) e intestino delgado (r=0,72; p=0,04) en el grupo control. En este grupo experimental el estómago glandular correlacionó en forma positiva y significativa con el peso del intestino delgado (r=0,93; p=0,0007). En el grupo alimentado con mucuna se registró una correlación positiva y significativa entre el peso relativo del tracto gastrointestinal y del estómago muscular (r=0,79; p=0,02). Se concluye que la incorporación de poroto mucuna produce un incremento en el peso relativo del tracto gastrointestinal. Teniendo en cuenta que dicho poroto podría emplearse en pollos como fuente alternativa de proteínas, se considera necesario profundizar los estudios sobre los métodos de eliminación de sus factores antinutricionales, para una más segura utilización práctica
Climatic and palaeoceanographic changes during the Pliensbachian (Early Jurassic) 2 inferred from clay mineralogy and stable isotope (C-O) geochemistry (NW Europe)
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Available online 17 January 2017The Early Jurassic was broadly a greenhouse climate period that was punctuated by short
warm and cold climatic events, positive and negative excursions of carbon isotopes, and
episodes of enhanced organic matter burial. Clay minerals from Pliensbachian sediments
recovered from two boreholes in the Paris Basin, are used here as proxies of detrital supplies,
runoff conditions, and palaeoceanographic changes. The combined use of these minerals with
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stable isotope data (C-O) from bulk carbonates and organic matter allows palaeoclimatic
reconstructions to be refined for the Pliensbachian. Kaolinite/illite ratio is discussed as a
reliable proxy of the hydrological cycle and runoff from landmasses. Three periods of
enhanced runoff are recognised within the Pliensbachian. The first one at the SinemurianPliensbachian
transition shows a significant increase of kaolinite concomitant with the
negative carbon isotope excursion at the so-called Sinemurian Pliensbachian Boundary Event
(SPBE). The Early/Late Pliensbachian transition was also characterised by more humid
conditions. This warm interval is associated with a major change in oceanic circulation during
the Davoei Zone, likely triggered by sea-level rise; the newly created palaeogeography,
notably the flooding of the London-Brabant Massif, allowed boreal detrital supplies, including
kaolinite and chlorite, to be exported to the Paris Basin. The last event of enhanced runoff
occurred during the late Pliensbachian (Subdonosus Subzone of the Margaritatus Zone),
which occurred also during a warm period, favouring organic matter production and
preservation. Our study highlights the major role of the London Brabant Massif in influencing
oceanic circulation of the NW European area, as a topographic barrier (emerged lands) during
periods of lowstand sea-level and its flooding during period of high sea-level. This massif was
the unique source of smectite in the Paris Basin. Two episodes of smectite-rich sedimentation
(‘smectite events’), coincide with regressive intervals, indicating emersion of the London
Brabant Massif and thus suggesting that an amplitude of sea-level change high enough to be
linked to glacio-eustasy. This mechanism is consistent with sedimentological and
geochemical evidences of continental ice growth notably during the Latest Pliensbachian
(Spinatum Zone), and possibly during the Early Pliensbachian (late Jamesoni/early Ibex
Zones).The study was supported by the “Agence Nationale pour la Gestion des Déchets Radioactifs” (Andra––French National Radioactive Waste Management Agency)
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