3,566 research outputs found

    Proposal and Description of a Test System with Wind, Hydro and Fossil Fuel Power Plants for Static Analyses

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    This article presents and describes a 229 bus test system that includes wind, hydro and fossil fuel power plants. It represents the Northeast subsystem of the Brazilian Interconnected Power System (BIPS). The test system supplies a load of 4.17 GW, being 13% powered by wind farms, which is the current wind power penetration level of the BIPS. The data comprehends different load levels based on the typical load behavior and typical capacity factors of wind, hydro and fossil fuel plants, as well as the capacity of transmission and sub-transmission lines, transformers, and the adopted structure for the test system. The data is compiled considering models and operating scenarios of the BIPS, and allow performing studies of static voltage stability, sensitivity of voltage stability margin considering the wind farms, and multi-objective optimization considering market constraints. The results of the simulations with the test system indicate the consistency of their data structure and its applicability to different studies of electric power systems.Comment: In proceedings of the 11th Bulk Power Systems Dynamics and Control Symposium (IREP 2022), July 25-30, 2022, Banff, Canad

    Synthesis of cubic ferrite CoFe2O4 by spray pyrolysis

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    The phase composition, morphology, and structural parameters of cobalt ferrospinel powders synthesized by spray pyrolysis combined with drop sol-gel combustion are determined. The obtained data are compared with those of the powders synthesized by sol-gel combustion

    Effect of preparation conditions on physic-chemical properties of tin-doped nanocrystalline indium oxide

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    In this paper the results of investigation of phase formation and change of concentration of free electrons (Ne) in indium tin oxide system during heat treatment of coprecipitated hydroxides of indium and tin from nitric and hydrochloric solutions and also, for comparison melts of salts nitrates by an alkaline reactant (NH4OH) are considered.The performed investigation allowed to set the optimal condition of preparation of polycrystalline tin-doped indium oxide with maximal electron concentration

    Voltage control of frequency, effective damping and threshold current in nano-constriction-based spin Hall nano-oscillators

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    Using micromagnetic simulations, we study the interplay between strongly voltage-controlled magnetic anisotropy (VCMA), ΔK=±\Delta K = \pm200 kJ/m3^3, and gate width, w=w= 10--400 nm, in voltage-gated W/CoFeB/MgO based nano-constriction spin Hall nano-oscillators. The VCMA modifies the local magnetic properties such that the magnetodynamics transitions between regimes of \emph{i}) confinement, \emph{ii}) tuning, and \emph{iii}) separation, with qualitatively different behavior. We find that the strongest tuning is achieved for gate widths of the same size as the the constriction width, for which the effective damping can be increased an order of magnitude compared to its intrinsic value. As a consequence, voltage control remains efficient over a very large frequency range, and subsequent manufacturing advances could allow SHNOs to be easily integrated into next-generation electronics for further fundamental studies and industrial applications

    Frequency and temperature dependence of the anomalous Hall conductivity in a chiral px+ipy superconductor with impurities

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    We calculate frequency and temperature dependence of the anomalous ac Hall conductivity induced by impurity scattering in a chiral px+ipy superconductor, such as Sr2RuO4, with spontaneous time-reversal-symmetry breaking in the absence of an external magnetic field. We consider two models of disorder, Gaussian and non-Gaussian, characterized by the second and third moments of the random impurity potential, respectively. Within both models, we find that the anomalous Hall conductivity has a finite real value at zero frequency, exhibits singularities at the threshold of photon absorption across the superconducting gap, and decays as some power of the high frequency \Omega. The Hall conductivity increases linearly with the decrease of temperature below the superconducting transition and saturates at zero temperature. Using our results for the high-frequency Hall conductivity, we estimate the polar Kerr angle for light reflection from the material and compare it with the experimental measurements in Sr2RuO4 by Xia et al., Phys. Rev. Lett. 97, 167002 (2006).Comment: 22 pages, 12 figures

    A STUDY OF EXTREMISM AS A COMPLEX INTER-BRANCH CONCEPT

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    Purpose: The aim of the study is to investigate extremism as a complex inter-branch concept which complicates law enforcement practice. Methodology: This is an analytic-dialectical research whose data are obtained through the analysis of historical, legal and sociological texts and data. Main Findings: When defining extremism in the basic law of anti-extremist legislation, it is necessary to proceed from the fact that the phenomenon, the concept of which should be formulated, is manifested in different spheres of social and political life. In conclusion, extremism creates an ideological basis for terrorism, but the acts of terrorism go beyond the concept of extremism. Applications: This article can be used by regional schools, cultural organizations and universities. Novelty/Originality: In this study, correlation between the phenomena of terrorism and extremism has been studied on the basis of definition for terrorist act given in part 1 of article 205 of the criminal code of the Russian Federation

    Effect of heat treatment on the structural parameters and magnetic properties of copper ferrite nanopowders obtained by the sol-gel combustion

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    Phase composition, structure parameters and basic magnetic characteristics obtained by the sol-gel combustion nanopowders of ferrospinel CuFe2O4 are investigated. A comparison of the properties of synthesized materials: first sample - immediately after the combustion of the gel and second sample - after annealing at 1073 K for 4 hours are performed. Annealing leads to an increase in the concentration of the phase with tetragonal crystal structure. Particle sizes and the value of anisotropy field of this phase also increased

    Spontaneous retroperitoneal hematoma, an uncommon case of acute surgical abdomen in a patient with hemophilia: case report

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    Hemophilia A is an X-linked hereditary disorder with a predilection for men. A worldwide incidence of 1 in 5 000 inhabitants is estimated. Currently, there is no curative treatment, which can lead to the development of multiple complications. However, abdominal presentations related to acute abdomen are uncommon and require surgical treatment. Similar cases are related to psoas muscle hematoma and hemophilic pseudotumors. We presented a 25-year-old male diagnosed with hemophilia A with acute abdominal pain and peritoneal irritation signs. After evaluation, we decided to perform a laparotomy, which reported a hematoma in the right mesocolon from the ileocecal valve to the hepatic flexure with right colic artery disruption. After seven days, he was discharged due to clinical improvement, and we indicated an outpatient general surgery follow-up. Acute abdomen caused by a retroperitoneal hematoma in patients with hemophilia is uncommon. Therefore, its management is still controversial. We concluded that a surgical approach might reduce the risk of complications in patients with poor clinical courses

    Gauge-invariant electromagnetic response of a chiral px+ipy superconductor

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    We present a gauge-invariant theory of the electromagnetic response of a chiral px+ipy superconductor in the clean limit. Due to the spontaneously broken time-reversal symmetry, the effective action of the system contains an anomalous term not present in conventional superconductors. As a result, the electromagnetic charge and current responses contain anomalous terms, which depend explicitly on the chirality of the superconducting order parameter. These terms lead to a number of unusual effects, such as coupling of the transverse currents to the collective plasma oscillations and a possibility of inducing the charge density by the magnetic field perpendicular to the conducting planes. We calculate the antisymmetric part of the conductivity tensor (the intrinsic Hall conductivity) and show that it depends on the wave vector of the electromagnetic field. We also show that the Mermin-Muzikar magnetization current and the Hall conductivity are strongly suppressed at high frequencies. Finally, we discuss implications of the theory to the experiments in Sr2RuO4.Comment: 22 pages, 4 figures, final version as published in PR
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