9 research outputs found
Impact of Corona Treatment on Mechanical Properties and Morphology of Hemp Fiber Reinforced in Epoxy Matrix Composite
No full textCorona treatment was applied to enhance the interfacial adhesion between hemp woven fibers and epoxy resin in fiber-reinforced composites. Using a cold pressing method with equal parts of resin and fiber (50 g each), samples were treated for 1–4 min. SEM analysis revealed that increased treatment time led to greater fiber surface roughness and reduced voids at the fiber–matrix interface, improving bonding. Tensile strength increased with treatment time, peaking at 48.68 MPa at 3 min before slightly decreasing at 4 min. The elastic modulus remained stable (304.67–312.52 MPa) up to 3 min, then dropped slightly to 302.86 MPa. Overall, corona-treated composites exhibited a 55% increase in tensile strength compared to untreated ones, confirming the treatment’s effectiveness in enhancing mechanical performance
A Combined Effect of Plasmon Energy Transfer and Recombination Barrier in a Novel TiO2/MgO/Ag Working Electrode for Dye-Sensitized Solar Cells
No full textNovel TiO2/MgO/Ag composite electrodes were applied as working electrodes of dye-sensitized solar cells (DSSCs). The TiO2/MgO/Ag composite films were prepared by dip coating method for MgO thin films and photoreduction method for Ag nanoparticles. The MgO film thicknesses and the Ag nanoparticle sizes were in ranges of 0.08–0.46 nm and 4.4–38.6 nm, respectively. The TiO2/MgO/Ag composite films were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The TiO2/MgO/Ag composite electrodes were sensitized by immersing in a 0.3 mM of N719 dye solution and fabricated for conventional DSSCs. J-V characteristics of the TiO2/MgO/Ag DSSCs showed that the MgO film thickness of 0.1 nm and the Ag nanoparticle size of 4.4 nm resulted in maximum short circuit current density and efficiency of 8.6 mA/cm2 and 5.2%, respectively. Electrochemical Impedance Spectroscopy showed that such values of short circuit current density and efficiency were optimal values obtained from plasmon energy transfer by 4.4 nm Ag nanoparticles and recombination barrier by the ultrathin MgO film
Effect of Silver Nanoparticle Size on Efficiency Enhancement of Dye-Sensitized Solar Cells
No full textTitanium dioxide/silver (TiO2/Ag) composite films were prepared by incorporating Ag in pores of mesoporous TiO2 films using a photoreduction method. The Ag nanoparticle sizes were in a range of 4.36–38.56 nm. The TiO2/Ag composite films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The TiO2 and TiO2/Ag composite films were then sensitized by immersing in a 0.3 mM N719 dye solution and fabricated for conventional dye-sensitized solar cells (DSCs). J-V characteristics of the TiO2/Ag DSCs showed that the Ag nanoparticle size of 19.16 nm resulted in the short circuit current density and efficiency of 8.12 mA/cm2 and 4.76%
Properties of archive resources of a cartographic and topo-bathymetric archive dataset on the French Rhône River
No full textThis dataset describes the properties of 350 data items. This table has 18 columns that include the following: (1) the type of data: i.e. map, cross-section, long profile, table, topo-bathymetry drawn on the map, (2) the source (archive service) and reference (box number), (3) the original title (in French) and a translated English title, (4) the scale, author, and survey period, (5) the communes covered by the upstream-downstream Kilometric Points (KPs; km 0 is in Lyon, distances upstream from this reference point are negative and distances downstream are positive; the KPs were identified in ArcMap 10.5 using the GIS layer of riverine communes and active channels in 1860, to help in locating the maps with secondary channels), (6) comments on the quality and content of the data, (7) the number of images and their type (on a table or a magnetic board, HD scan, scanned and georeferenced), and (8) the storage file and sub-file
Les attentes des salariés en matière d'épargne salariale
No full textEmployees’ wishes as regards company savings plan
This article deals with the main expectations of the French Comité intersyndical de l’épargne salariale (CIES) as regards company savings plan’s managers. The first employees’ wish is obviously the service’s quality. It first implies a wide range of financial products. Moreover, the costs’ transparency is a real issue as regards company savings plan. The third sensitive issue concerns funds management’s control by employees’ representatives. At last, the author raises the question of the socially responsible investment.
JEL classification : D91, G11, G23, G28Cet article revient sur les principales attentes du Comité intersyndical de l’épargne salariale (CIES) à l’égard des gestionnaires. La première attente des épargnants est naturellement la qualité de service. Elle passe en premier lieu par l’étendue de l’offre de produits proposée aux salariés. Par ailleurs, la question de la transparence des frais est une vraie question en matière d’épargne salariale. Le troisième sujet sensible est celui du contrôle de la gestion des fonds par les représentants des salariés. Enfin, la quatrième question est celle de l’investissement socialement responsable.
Classification JEL : D91, G11, G23, G28Chanu Pierre-Yves. Les attentes des salariés en matière d'épargne salariale. In: Revue d'économie financière, n°79, 2005. L'industrie de la gestion d'actifs. pp. 61-65
Cartographic and topo-bathymetric archive dataset on the French Rhône River (17th-20th centuries)
No full textThis dataset presents 350 cartographic and topo-bathymetric resources on the French Rhône River (530 km in length) compiled from the 17th to mid-20th century, with a temporal focus prior to extensive river training (1860s). The data were collected in 14 national, regional, and departmental archive services: National Archives of Pierrefitte-sur-Seine (AN), Bibliothèque nationale de France (BnF), National Institute of Geographic and forest information (IGN), National Company of the Rhône River (CNR), Regional Directorate for Environment, Development and Housing (DREAL), University of Grenoble, Departmental Archives of Rhône (AD69), Ain (AD01), Gard (AD30), Savoie (AD73), Drôme (AD26), Ardèche (AD07), Isère (AD38), and Vaucluse (AD84).
This database contains four datasets:
- The iconographic dataset. The archived resources contain 3436 images stored in 32 files and 342 sub-files.
- The table describing the properties of the 350 data items. This table has 18 columns that include the following: (1) the type of data: i.e. map, cross-section, long profile, table, topo-bathymetry drawn on the map, (2) the source (archive service) and reference (box number), (3) the original title (in French) and a translated English title, (4) the scale, author, and survey period, (5) the communes covered by the upstream-downstream Kilometric Points (KPs; km 0 is in Lyon, distances upstream from this reference point are negative and distances downstream are positive; the KPs were identified in ArcMap 10.5 using the GIS layer of riverine communes and active channels in 1860, to help in locating the maps with secondary channels), (6) comments on the quality and content of the data, (7) the number of images and their type (on a table or a magnetic board, HD scan, scanned and georeferenced), and (8) the storage file and sub-file.
- The table listing the 281 archive box references consulted in this study.
- The GIS polyline layer of the longitudinal coverage of the 350 data items (geographic coordinate system: WGS84 EPSG 4326)
On the optimality of coin-betting for mean estimation
No full textWe consider the problem of testing the mean of a bounded real random variable. We introduce a notion of optimal classes for e-variables and e-processes, and establish the optimality of the coin-betting formulation among e-variable-based algorithmic frameworks for testing and estimating the (conditional) mean. As a consequence, we provide a direct and explicit characterisation of all valid e-variables and e-processes for this testing problem. In the language of classical statistical decision theory, we fully describe the set of all admissible e-variables and e-processes, and identify the corresponding minimal complete class.The author would like to thank Gergely Neu, Peter D. Grünwald, Nishant A. Mehta, Hamish E. Flynn, and Claudia M. Chanu, for the insightful discussions that inspired this work. I would also like to thank Nick W. Koning and Aditya Ramdas for their constructive feedback, which helped improve this work following its initial appearance, and Wouter M. Koolen for helpful discussions on e-processes. Finally, I thank the anonymous reviewers for the insightful comments and feedback that helped improving this work. GPT-4o was used during the redaction of this paper to polish the presentation. All AI-generated text was reviewed and edited by the author, who takes full responsibility for the content of this manuscript. This project was funded by the European Research Council (ERC), under the European Union's Horizon 2020 research and innovation programme (grant agreement 950180)
Are Orthogonal Separable Coordinates Really Classified?
No full textWe prove that the set of orthogonal separable coordinates on an arbitrary (pseudo-)Riemannian manifold carries a natural structure of a projective variety, equipped with an action of the isometry group. This leads us to propose a new, algebraic geometric approach to the classification of orthogonal separable coordinates by studying the structure of this variety. We give an example where this approach reveals unexpected structure in the well known classification and pose a number of problems arising naturally in this context.This paper is a contribution to the Special Issue on Analytical Mechanics and Dif ferential Geometry in honour
of Sergio Benenti. The full collection is available at http://www.emis.de/journals/SIGMA/Benenti.html.
This notice is based on a talk held at the workshop “Analytical Mechanics and Dif ferential
Geometry” at the Universit`a di Torino on 12th and 13th March 2015 on the occasion of Sergio
Benenti’s 70th birthday. The author would like to thank the organisers, Claudia Chanu and
Giovanni Rastelli, for their kind invitation and hospitality, as well as Willard Miller for valuable
discussions on the subject
Saturated absorption spectroscopy using azimuthally structured mode in hollow-core fiber
No full textInternational audienceWe report on transversally structured beam effect on saturated absorption spectroscopy in acetylene-filled hollow-core fiber. Experimental results reveal frequency shift and contrast enhancement of absorption lines using LP11 guided mode rather than gaussian-like mode. © 2022 The Author(s) Sub-Doppler spectroscopy such as electromagnetically induced transparency (EIT) or saturated absorption spectroscopy (SAS) is usually performed with a Gaussian mode profile both in free-space and guided optics configurations. Recently, in free space, works have been reported where Laguerre-Gaussian (LG) modes have been set as pump or probe beams in EIT [1-5] and SAS [6] schemes in Rb vapors. Radial variation of LG mode induces narrowing of Doppler-free transparencies profiles. Chanu et al. [1] demonstrated decrease of resonances linewidths of Rb of almost factor 6 switching from Gaussian to LG mode. For [5], LG modes contribute to increase the Rb Zeeman level lifetime and so decrease the FWHM. Furthermore, influence of LG modes order has also been studied in [2] demonstrating that larger order induces narrower signal due to its azimuthal component and authors of [4] present the influence of transverse mode overlap (pump and probe) on the signal. Gas-filled HCPCF technology already demonstrated its potential and impact on the enhancement of the light-gas interactions phenomena and especially in spectroscopy. The various works deriving from the seminal demonstration [7] have been limited to pump (or pump-probe) Gaussian beam configurations due to the fact that most of the developments on HCPCFs have been focused on the design and fabrication of fibers supporting the lowest loss LP01 like mode with the main objective to increase transmission performances. Moreover, the intrinsic cladding modal properties of microstructured hollow-core fibers render difficult the control on the loss mode hierarchy and to guide light in a high order single mode fashion. This restriction has been lifted by the emergence of the tubular cladding HCPCF providing a large flexibility on the tubes cladding position. Thanks to alteration of the azimuthal position of the cladding tubes, Osorio et al. [8] demonstrated, theoretically and experimentally, for the first time in a HCPCF, an inversion of the classical loss hierarchy in fibers developing fibers whose lowest loss modes are the LP11 and LP21, instead of the LP01. In this study, we specifically design and fabricate a fiber based on this geometry allowing to guide preferentially high order mode (HOM) around 1550nm without any specific light coupling precaution, we report for the first time to the best of our knowledge on SA spectroscopy generated in HCPCF with a LP11 high-order mode control beam. Comparison with Gaussian control beam configuration demonstrates an increase of the contrast and peak position shift
