825 research outputs found

    Determination of Stability and Control Derivatives for a Modern Light Composite Twin Engine Airplane

    Get PDF
    To develop and compare full envelope stability and control derivatives and their associated errors for a modern light composite twin engine airplane from flight test data and digital DATCOM (Data Compendium). This development is to serve three purposes 1) to provide data for validation of newer analytical techniques such as Computational Fluid Dynamics (CFD), 2) to provide public domain static and dynamic stability and control derivatives for a modern twin engine airplane, 3) to analyze the relationship between test design and error for both output error and equation error methods. A flight test program was conducted on a Diamond Twin Star DA42 with Thielert engines and on a DA42 with Lycoming engines by Embry-Riddle Aeronautical University. For the theoretical verification the equation error and output error methods in both time and frequency domain within System Identification Programs for AirCraft (SIDPAC), were used. The DATCOM analysis was based on airplane drawings and direct measurement on the DA42 airframe. The results for both methods and error associated with SIDPAC were compared to Digital DATCOM results

    An Applied Electromagnetics Course with a Conceiving-Designing-Implementing-Operating Approach in Engineering Education

    Get PDF
    This paper describes and discusses the implementation of a project-based undergraduate course on applied electromagnetics in electronics engineering with a conceiving-designing-implementing-operating (CDIO) approach involving active project-based learning (PBL). The course, which requires a combination of mathematical and physics concepts for its completion, allows students to understand the principles of electromagnetic transmission theory in wireless communication systems. This paper presents the course proposal, its project description, and results hinting at the relationship with the CDIO process. The proposed projects allow students to engage in core concepts such as complex vectors, Maxwell’s equations, boundary conditions, Poynting\u27s theorem, uniform plane waves, reflection and transmission of waves, waveguides, cavity resonators, and computer-assisted design. The proposed methodology results suggest that students lowered their perception of the difficulty of the course, and most students recognized a better learning process of the core concepts for this course. In addition, students’ final course grades showed an average improvement of approximately 6% compared with the final grades of other groups with different methodologies

    Financial Stability Governance and Communication

    Full text link
    Resumen de la comunicación[EN] We investigate how differences in governance frameworks across central banks explain their financial stability communication strategies and the effect of these strategies on the evolution of each country’s financial cycle. To do so, we propose a simple conceptual framework that explains how central banks conduct their communication strategy, which eventually affects the evolution of financial conditions. To empirically validate our framework, we use a database with the financial stability governance characteristics of 24 central banks and the sentiment conveyed in the financial stability reports published by these central banks. We find that, after observing a deterioration of financial conditions, central banks participating in interagency financial stability committees or with an oversight role transmit a calmer message than banks without these characteristics. We also find that the effect of communication on the evolution of the financial cycle depends on each central bank's governance framework. In particular, communication by central banks participating in an interagency financial stability committee or with a financial supervisory role has an alleviating effect on the deterioration of financial conditions.Londono, JM.; Claessens, S.; Correa, R.; Mislang, N. (2018). Financial Stability Governance and Communication. En 2nd International Conference on Advanced Reserach Methods and Analytics (CARMA 2018). Editorial Universitat Politècnica de València. 262-262. https://doi.org/10.4995/CARMA2018.2018.8577OCS26226

    Co-simulation Management Algorithm for Distribution System Operation with Real-Time Simulator

    Get PDF
    This article presents a co-simulation framework consistent with the real-time simulation for operational analysis of electrical distribution networks. Realtime simulators have become a fundamental tool for testing and optimising control strategies in a safe and controlled environment. The proposed methodology outlines the steps required for setting up, controlling, and monitoring an electrical grid using a real-time simulator. The framework proposes the use of the Message Queuing Telemetry Transport communication between the electrical grid module and an external coordinator. An algorithm based on the Python programming language is proposed to manage the real-time simulation, create the grid topology, and communicate with the external coordinator. The implementation of the electrical network and the validation of the real-time simulator network are also presented. The article concludes that the proposed framework can improve the performance and flexibility of co-simulation for studies on the penetration of power electronics-based renewable sources

    High-order dispersion mapping of an optical fiber

    Get PDF
    We report on measurements of high-order dispersion maps of an optical fiber, showing how the ratio between the third and fourth-order dispersion (β3/β4) and the zero-dispersion wavelength (λ0) vary along the length of the fiber. Our method is based on Four-Wave Mixing between short pulses derived from an incoherent pump and a weak laser. We find that the variations in the ratio β3/β4 are correlated to those in λ0. We present also numerical calculations to illustrate the limits on the spatial resolution of the method. Due to the good accuracy in measuring λ0 and β3/β4 (10 -3% and 5% relative error, respectively), and its simplicity, the method can be used to identify fiber segments of good uniformity, suitable to build nonlinear optical devices such as parametric amplifiers and frequency comb generators28342584273FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2012/50259-8; 2015/11779-4; 2017/16151-9; 2018/08988-9; 2019/16793-6Fundação de Amparo à Pesquisa do Estado de São Paulo (2012/50259-8, 2015/11779-4, 2017/16151-9, 2018/08988-9, 2019/16793-6); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; Departamento Administrativo de Ciencia, Tecnología e Innovación (COLCIENCIAS) (COL-10-2-05

    Connecting in Real-time Power System Labs: An Italian Test-case

    Get PDF
    Sharing of hardware and software facilities together with knowledge and expertise among laboratories is a key point in research. In the power systems field this is possible even remotely by coupling real-time simulators located in different laboratories. In this paper an experimental test-bed is described. It consists of the remote interconnection of the realtime simulators, located at Politecnico di Torino and Politecnico di Bari respectively, in order to perform Remote Power Hardware-in-the-Loop experiments. The possibilities and limitations of this type of co-simulation are described and a case study is presented

    Arthropod EVs Mediate Dengue Virus Transmission Through Interaction With a Tetraspanin Domain Containing Glycoprotein Tsp29Fb

    Get PDF
    Dengue virus (DENV) is a mosquito-borne flavivirus that causes dengue fever in humans, worldwide. Using in vitro cell lines derived from Aedes albopictus and Aedes aegypti, the primary vectors of DENV, we report that DENV2/DENV3-infected cells secrete extracellular vesicles (EVs), including exosomes, containing infectious viral RNA and proteins. A full-length DENV2 genome, detected in arthropod EVs, was infectious to naïve mosquito and mammalian cells, including human-skin keratinocytes and blood endothelial cells. Cryo-electron microscopy showed mosquito EVs with a size range from 30 to 250 nm. Treatments with RNase A, Triton X-100, and 4G2 antibody-bead binding assays showed that infectious DENV2-RNA and proteins are contained inside EVs. Viral plaque formation and dilution assays also showed securely contained infectious viral RNA and proteins in EVs are transmitted to human cells. Up-regulated HSP70 upon DENV2 infection showed no role in viral replication and transmission through EVs. In addition, qRT-PCR and immunoblotting results revealed that DENV2 up-regulates expression of a mosquito tetraspanin-domain–containing glycoprotein, designated as Tsp29Fb, in A. aegypti mosquitoes, cells, and EVs. RNAi-mediated silencing and antibody blocking of Tsp29Fb resulted in reduced DENV2 loads in both mosquito cells and EVs. Immunoprecipitation showed Tsp29Fb to directly interact with DENV2 E-protein. Furthermore, treatment with GW4869 (exosome-release inhibitor) affected viral burden, direct interaction of Tsp29Fb with E-protein and EV-mediated transmission of viral RNA and proteins to naïve human cells. In summary, we report a very important finding on EV-mediated transmission of DENV2 from arthropod to mammalian cells through interactions with an arthropod EVs-enriched marker Tsp29Fb

    Ice XII in its second regime of metastability

    Full text link
    We present neutron powder diffraction results which give unambiguous evidence for the formation of the recently identified new crystalline ice phase[Lobban et al.,Nature, 391, 268, (1998)], labeled ice XII, at completely different conditions. Ice XII is produced here by compressing hexagonal ice I_h at T = 77, 100, 140 and 160 K up to 1.8 GPa. It can be maintained at ambient pressure in the temperature range 1.5 < T < 135 K. High resolution diffraction is carried out at T = 1.5 K and ambient pressure on ice XII and accurate structural properties are obtained from Rietveld refinement. At T = 140 and 160 K additionally ice III/IX is formed. The increasing amount of ice III/IX with increasing temperature gives an upper limit of T ~ 150 K for the successful formation of ice XII with the presented procedure.Comment: 3 Pages of RevTeX, 3 tables, 3 figures (submitted to Physical Review Letters
    • …
    corecore