31 research outputs found

    Factors that drive female entrepreneurship in Armenia

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    Entrepreneurs play a key role in any economy. Entrepreneurship includes creativity, innovation, risk taking, planning and management and is described as transferring ideas into action. In the light of recent world events, female entrepreneurship has become a crucial area to study and understand, especially with respect to motivations, obstacles, constraints and consequences of female entrepreneurship. The research work focuses on female entrepreneurship in a developing country - Armenia – and proposes a conceptual framework of the phenomenon. A logistic regression econometric method is applied to the dataset of World Bank (2013) to identify and measure the relationship between female entrepreneurship and several factors such as the location, size, legal status, market and obstacles faced by Armenian firms.info:eu-repo/semantics/publishedVersio

    Electromagnetic wave propagation in spatially homogeneous yet smoothly time-varying dielectric media

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    We explore the propagation and transformation of electromagnetic waves through spatially homogeneous yet smoothly time-dependent media within the framework of classical electrodynamics. By modelling the smooth transition, occurring during a finite period {\tau}, as a phenomenologically realistic and sigmoidal change of the dielectric permittivity, an analytically exact solution to Maxwell's equations is derived for the electric displacement in terms of hypergeometric functions. Using this solution, we show the possibility of amplification and attenuation of waves and associate this with the decrease and increase of the time-dependent permittivity. We demonstrate, moreover, that such an energy exchange between waves and non-stationary media leads to the transformation (or conversion) of frequencies. Our results may pave the way towards controllable light-matter interaction in time-varying structures.Comment: 5 figure

    Electron States and Light Absorption in Strongly Oblate and Strongly Prolate Ellipsoidal Quantum Dots in Presence of Electrical and Magnetic Fields

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    In framework of the adiabatic approximation the energy states of electron as well as direct light absorption are investigated in strongly oblate and strongly prolate ellipsoidal quantum dots (QDs) at presence of electric and magnetic fields. Analytical expressions for particle energy spectrum are obtained. The dependence of energy levels’ configuration on QD geometrical parameters and field intensities is analytically obtained. The energy levels of electrons are shown to be equidistant both for strongly oblate and prolate QDs. The effect of the external fields on direct light absorption of a QD was investigated. The dependence of the absorption edge on geometrical parameters of QDs and intensities of the electric and magnetic fields is obtained. Selection rules are obtained at presence as well as absence of external electric and magnetic fields. In particular, it is shown that the presence of the electric field cancels the quantum numbers selection rules at the field direction, whereas in radial direction the selection rules are preserved. Perspectives of practical applications for device manufacturing based on ellipsoidal quantum dots are outlined

    Electronic States and Light Absorption in a Cylindrical Quantum Dot Having Thin Falciform Cross Section

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    Energy level structure and direct light absorption in a cylindrical quantum dot (CQD), having thin falciform cross section, are studied within the framework of the adiabatic approximation. An analytical expression for the energy spectrum of the particle is obtained. For the one-dimensional “fast” subsystem, an oscillatory dependence of the wave function amplitude on the cross section parameters is revealed. For treatment of the “slow” subsystem, parabolic and modified Pöschl-Teller effective potentials are used. It is shown that the low-energy levels of the spectrum are equidistant. In the strong quantization regime, the absorption coefficient and edge frequencies are calculated. Selection rules for the corresponding quantum transitions are obtained

    Interferometric detection of nanoparticles

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    Interferometric surfaces enhance light scattering from nanoparticles through constructive interference of partial scattered waves. By placing the nanoparticles on interferometric surfaces tuned to a special surface phase interferometric condition, the particles are detectable in the dilute limit through interferometric image contrast in a heterodyne light scattering configuration, or through diffraction in a homodyne scattering configuration. The interferometric enhancement has applications for imaging and diffractive biosensors. We present a modified model based on Double Interaction (DI) to explore bead-based detection mechanisms using imaging, scanning and diffraction. The application goal of this work is to explore the trade-offs between the sensitivity and throughput among various detection methods. Experimentally we use thermal oxide on silicon to establish and control surface interferometric conditions. Surface-captured gold beads are detected using Molecular Interferometric Imaging (MI2) and Spinning-Disc Interferometry (SDI). Double-resonant enhancement of light scattering leads to high-contrast detection of 100 nm radius gold nanoparticles on an interferometric surface. The double-resonance condition is achieved when resonance (or anti-resonance) from an asymmetric Fabry-Perot substrate coincides with the Mie resonance of the gold nanoparticle. The double-resonance condition is observed experimentally using molecular interferometric imaging (MI2). An invisibility condition is identified for which the gold nanoparticles are optically cloaked by the interferometric surface

    "Extraction séquentielle de molécules à haute valeur ajoutée à partir de pulpes de raisin en utilisant des fluides supercritiques avec l'eau comme co-solvant

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    Inspired by the concept of organic waste valorisation and heading towards a sustainable economy, a green chemistry extraction technique involving supercritical carbon dioxide (SC-CO2) along with water as a cosolvent was employed for the main winery by-product (grape pomaces). The objective was to selectively extract high-value added molecules, in particular phenolic compounds and polysaccharides. The experimental design involved applying three distinct temperature conditions (40, 60, and 80 °C), and a constant pressure of 400 bar. Phenolic compounds and high-molecular weight isolates (449-478 kDa) containing low methoxyl (% DE = 23) pectic substances were detected in the SC-CO 2 extracts accompanied by water as a co-solvent. The phenolic acids, namely, gallic (GA), protocatechuic (PCA), coumaric (CouA), and caftaric (CTA), and flavonoids, namely, procyanidin B1 (PRC B1), procyanidin B 2 (+) (PRC B 2), (+) catechin (CT), and (−) epicatechin (ECT) were found in all the extracts under the tested experimental conditions. The following study underscores the potential of the pressurized CO 2 /H 2 O medium as an effective solvent with minimal environmental impacts for the comprehensive valorisation of the main winery by-product, specifically targeting polysaccharides and phenolic compounds. Sustainability spotlight This study focuses on the extraction of valuable molecules such as polyphenols and bers from grape pomace, a by-product of wine production, using a green chemistry technique called supercritical uid extraction. These extracted molecules have potential applications as antioxidants in wine production. The research highlights the signicance of specic United Nations sustainable development goals, including affordable and clean energy (SDG 7), industry, innovation, and infrastructure (SDG 9), and climate action (SDG 13)

    Commissioning of L1Calo Phase I Upgrade at ATLAS: development and testing of eFEX and FTM modules

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    The ATLAS level-1 calorimeter trigger (L1Calo) is a hardware system that identifies events containing calorimeter-based physics objects. In preparation for Run 3 with increased pileup (Ό∌65\mu\sim65), L1Calo is currently implementing a significant programme of planned upgrades. The existing hardware will be replaced by a new system of feature extractor (FEX) modules with improved input granularity and algorithms. Here we focus on the current ongoing testing and commissioning of the electron feature extractor (eFEX) and the FEX Test Module (FTM) at the recent slice tests at CERN. The online software developments required to do this are also discussed

    The DUNE Far Detector Vertical Drift Technology, Technical Design Report

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    International audienceDUNE is an international experiment dedicated to addressing some of the questions at the forefront of particle physics and astrophysics, including the mystifying preponderance of matter over antimatter in the early universe. The dual-site experiment will employ an intense neutrino beam focused on a near and a far detector as it aims to determine the neutrino mass hierarchy and to make high-precision measurements of the PMNS matrix parameters, including the CP-violating phase. It will also stand ready to observe supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector implements liquid argon time-projection chamber (LArTPC) technology, and combines the many tens-of-kiloton fiducial mass necessary for rare event searches with the sub-centimeter spatial resolution required to image those events with high precision. The addition of a photon detection system enhances physics capabilities for all DUNE physics drivers and opens prospects for further physics explorations. Given its size, the far detector will be implemented as a set of modules, with LArTPC designs that differ from one another as newer technologies arise. In the vertical drift LArTPC design, a horizontal cathode bisects the detector, creating two stacked drift volumes in which ionization charges drift towards anodes at either the top or bottom. The anodes are composed of perforated PCB layers with conductive strips, enabling reconstruction in 3D. Light-trap-style photon detection modules are placed both on the cryostat's side walls and on the central cathode where they are optically powered. This Technical Design Report describes in detail the technical implementations of each subsystem of this LArTPC that, together with the other far detector modules and the near detector, will enable DUNE to achieve its physics goals