Selection of Digital Filter for Microprocessor Protection Relays

The article considers some issues related to replacement of electromechanical relays used for protection of power facilities with microprocessor relays. One of the urgent problems connected with implementation of microprocessor overcurrent protections is how to use current transducers other than usual current transformers and in particular Rogowski coils that become more and more widespread. In the article are compared twelve methods of synthesis of a digital filter basing on the analog prototype – second-order integrating filter. The bilinear filter and Boxer-Thaler filters are analyzed in respect to their use in microprocessor relays. Basing on the research results a technique for selection of parameters of digital integrating filters for microprocessor relays is proposed. Simulation results show that Boxer-Thaler and bilinear filters have better accuracy during transient current measurements than the analog filter. The study allows concluding that in many cases the digital second-order bilinear filter is the best choice for use in microprocessor relays

Assessment of mesoscale eddy parameterizations for coarse resolution ocean models

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1999Climate simulation with numerical oceanic models requires a proper parameterization scheme in order to represent the effects of unresolved mesoscale eddies. Even though a munber of schemes have been proposed and some have led to improvements in the simulation of the bulk climatological properties, the success of the parameterizations in representing the mesoscale eddies has not been investigated in detail. This thesis examines the role of eddies in a 105-years long basin scale eddy resolving simulation with the MIT General Circulation Model (GCM) forced by idealized wind stress and relaxation to prescribed meridional temperature; this thesis also evaluates the Fickian diffusive, the diabatic Green-Stone (GS) and the quasi-adiabatic Gent-McWilliams (GM) parameterizations in a diagnostic study and a series of coarse resolution experiments with the same model in the same configuration. The mesoscale eddies in the reference experiment provide a significant contribution to the thermal balance in limited areas of the domain associated with the upper 1000M of the boundary regions. Specifically designed diagnostic tests of the schemes show that the horizontal and vertical components of the parameterized flux are not simultaneously downgradient to the eddy heat flux. The transfer vectors are more closely aligned with the isopycnal surfaces for deeper layers, thus demonstrating the adiabatic nature of the eddy heat flux for deeper layers. The magnitude of the coefficients is estimated to be consistent with traditionally used values. However, the transfer of heat associated with timedependent motions is identified as a complicated process that cannot be fully explained with any of the local parameterization schemes considered. The eddy parameterization schemes are implemented in the coarse resolution configuration with the same model. A series of experiments exploring the schemes' parameter space demonstrate that Fickian diffusion has the least skill in the climatological simulations because it overestimates the temperature of the deep ocean and underestimates the total heat transport. The GS and GM schemes perform better in the simulation of the bulk climatological properties of the reference solution, although the GM scheme in particular produces an ocean that is consistently colder than the reference state. Comparison of the eddy heat flux divergence with the parameterized divergences for typical parameter values demonstrates that the success of the schemes in the climatological simulation is not related to the representation of the eddy heat flux but to the representation of the overall internal mixing processes.The financial support for this research was provided by ONR grant number NOOOl4- 98-1-0881, Alliance for Global Sustainability and American Automobile Manufactures Association

A Discontinuous Galerkin Method for Ideal Two-Fluid Plasma Equations

A discontinuous Galerkin method for the ideal 5 moment two-fluid plasma system is presented. The method uses a second or third order discontinuous Galerkin spatial discretization and a third order TVD Runge-Kutta time stepping scheme. The method is benchmarked against an analytic solution of a dispersive electron acoustic square pulse as well as the two-fluid electromagnetic shock and existing numerical solutions to the GEM challenge magnetic reconnection problem. The algorithm can be generalized to arbitrary geometries and three dimensions. An approach to maintaining small gauge errors based on error propagation is suggested.Comment: 40 pages, 18 figures

Complexation of lithium and sodium cations with B-phosphorylate ethers, modelling terminal groups of organophosphorus podands. An experimental and theoretical study

The organophosphorus compounds o-Ph2P(O)C6H4OCH3 and Ph2P(O)C2H4OCH3, which are analogs of podands' terminal groups, have been synthesized. The thermodynamic characteristics of their complexation with LiNCS and NaNCS in acetonitrile were obtained by calorimetry. Molecular mechanics calculations on M+ L complexes with different stoichiometries M+:L = 1:1, 1:2 and 1:4 (M+ = Li+, Na+) were performed, as well as on their solvates with a limited number of MeCN molecules. It has been shown that the experimental data could be explained by taking into account both the specific features of the complex structure and the solvent effects. The possibility of the application of additive schemes in the investigation of the complexation of polydentate molecules is discussed

Self-improving Multiplane-to-layer Images for Novel View Synthesis

We present a new method for lightweight novel-view synthesis that generalizes to an arbitrary forward-facing scene. Recent approaches are computationally expensive, require per-scene optimization, or produce a memory-expensive representation. We start by representing the scene with a set of fronto-parallel semitransparent planes and afterward convert them to deformable layers in an end-to-end manner. Additionally, we employ a feed-forward refinement procedure that corrects the estimated representation by aggregating information from input views. Our method does not require fine-tuning when a new scene is processed and can handle an arbitrary number of views without restrictions. Experimental results show that our approach surpasses recent models in terms of common metrics and human evaluation, with the noticeable advantage in inference speed and compactness of the inferred layered geometry, see https://samsunglabs.github.io/MLIComment: Accepted for WACV 202

Economic growth and quality of institutions in 27 postsocialist economies

Purpose – The relationship between institutional quality and economic growth is revisited. Design/methodology/approach – A panel cointegration methodology and causality analysis are applied to 27 postsocialist economies over the period from 1996 to 2016. Findings – Utilizing the Worldwide Governance Indicators as a means of assessing the quality of institutions, it is found that in the long run, economic growth is positively associated with the rule of law and voice and accountability. In the short run, regulatory quality retains a positive effect, but voice and accountability demonstrate a puzzling negative effect on economic growth that merits further analysis. In exploring the causal dimension of our variables, supporting evidence of the strong links between the quality of institutions and economic growth is provided, hence rendering robust results. Originality/value – To the best of the authors’ knowledge, it is the first time that an ARDL methodological framework, which addresses potential endogeneity issues, is used to investigate the relationship between institutional quality and growth in the context of postsocialist economies

Toroidal equilibria in spherical coordinates

The standard Grad-Shafranov equation for axisymmetric toroidal plasma equilibrium is customary expressed in cylindrical coordinates with toroidal contours, and through which benchmark equilibria are solved. An alternative approach to cast the Grad-Shafranov equation in spherical coordinates is presented. This equation, in spherical coordinates, is examined for toroidal solutions to describe low $\beta$ Solovev and high $\beta$ plasma equilibria in terms of elementary functions