cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The quantum optics of asymmetric mirrors with coherent light absorption
Creators: name: Dawson, Benjamin
name: Furtak-Wells, Nicholas
name: Mann, Thomas
name: Jose, Gin
name: Beige, Almut
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The local observables of the quantised electromagnetic field near a mirror-coated interface depend strongly on the properties of the media on {\em both} sides. In macroscopic quantum electrodynamics, this fact is taken into account with the help of optical Green's functions which correlate the position of an observer with all other spatial positions and photon frequencies. Here we present an alternative, more intuitive approach and obtain the local field observables with the help of a quantum mirror image detector method [Furtak-Wells et al., Phys. Rev. A 97, 043827 (2018)]. In order to correctly normalise electric field operators, we demand that spontaneous atomic decay rates simplify to their respective free space values far away from the reflecting surface. Our approach is interesting, since mirror-coated interfaces constitute a common basic building block for quantum photonic devices.
description: 21 pages, 7 figures
Nutritional assessment of agricultural migrant workers in southern Brazil
Creators: name: Swann, Marjorie Anne
Publisher: name: University of British Columbia
Year: 2010

description: With the urbanization phenomenon, a population of unskilled migrant workers commonly known as Boia- Frias has rapidly grown up in slums on the peripheries of Brazilian cities. This study was carried put to assess the food habits and nutritional status of 100 Boia-Fria families of Vila Recreio, a slum area on the edge of Ribeirao Preto, S.P., Brazil, using dietary, anthropometric, and biochemical investigations. Qualitatively, the Boia-Fria diet was monotonous and simple, consisting basically of polished rice, beans, white bread, and coffee with sugar. In general, the foods which were lacking were: milk products, meats, fish, eggs, poultry, non-refined grain products, and fruits and vegetables rich in vitamins A and C. Foods of low nutritional value such as starchy gruels, sugar-water, herb tea, coffee with sugar and soft drinks were commonly used as weaning foods. Although dietary practices of pregnant and lactating women were poor, breastfeeding was still practiced by most mothers. According to 24-hour dietary recall data, conditions existed which were conducive to the development of nutritional problems, especially with respect to calcium, vitamin A, riboflavin, niacin, vitamin C, and iron, of the nutrients tested and with respect to quantitative intake of food. Biochemical data confirmed the presence of early malnutrition, pre-clinical in nature for about 257o of the population with respect to vitamin A, carotene, and iron. Plasma cholesterol, total lipid and vitamin E values were found to be normal. Anthropometric examinations revealed clear signs of clinical undernutrition among men and women as well as some degree of obesity among women. Child mortality data provided evidence of some advanced clinical malnutrition among children. Basic causes of malnutrition among the Boia-Frias included the following ecological factors: recent urbanization; housing, sanitation, and environmental conditions, associated with serious infection problems; poverty; illiteracy; and an ignorance of what constitutes good nutrition. Recommendations for intervention and "long-range" nutrition programs to minimize the harsh effects of poverty and upheaval on these migrant workers of Brazil were suggested.
Common origin of quasi-periodic pulsations in microwave and decimetric solar radio bursts
Creators: name: Kashapova, Larisa
name: Kolotkov, Dmitrii
name: Kupriyanova, Elena
name: Kudriavtseva, Anastasiia
name: Tan, Chengming
name: Reid, Hamish
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We analyse quasi-periodic pulsations (QPP) detected in the microwave and decimeter radio emission of the SOL2017-09-05T07:04 solar flare, using simultaneous observations by the Siberian Radioheliograph 48 (SRH-48, 4-8 GHz) and Mingantu Spectral Radioheliograph (MUSER-I, 0.4-2 GHz). The microwave emission was broadband with a typical gyrosynchrotron spectrum, while a quasi-periodic enhancement of the decimetric emission appeared in a narrow spectral band (500-700 MHz), consistent with the coherent plasma emission mechanism. The periodicity that we found in microwaves is about 30 s, coming from a compact loop-like source with a typical height of about 31 Mm. The decimetric emission demonstrated a periodicity about 6 s. We suggested a qualitative scenario linking the QPPs observed in both incoherent and coherent spectral bands and their generation mechanisms. The properties of the QPPs found in the microwave signal are typical for perturbations of the flare loop by the standing sausage mode of a fast magnetohydrodynamic (MHD) wave. Our analysis indicated that this sausage-oscillating flare loop was the primary source of oscillations in the discussed event. The suggested scenario is that a fundamental sausage harmonic is the dominant cause for the observed QPPs in the microwave emission. The initiation of oscillations in the decimetric emission is caused by the third sausage harmonic via periodic and nonlinear triggering of the acceleration processes in the current sheets, formed at the interface between the sausage-oscillating flare loop and the external coronal loop that extended to higher altitudes. Our results demonstrate the possible role of MHD wave processes in the release and transport of energy during solar flares, linking coherent and incoherent radio emission mechanisms.
description: 18 pages, 7 figures, accepted to Solar Physics
title:  Aesthetics and Environmental Dereliction The Ambiguous Sublimity of Destroyed Environments
Creators: name: Somhegyi  , Zoltan
Publisher: name: Roma TrE-Press
Year: 2021

description: Destroyed natural environments and derelict urban and industrial sites may all evoke an ambiguously disturbing sublimity. Landscapes that are devastated through heavy industrial activity or seriously altered due to climate change as well as decaying urban and industrial sites can all lead to challenging our notion of aesthetic experience. Both these types of decay, i.e. the ones concerning the natural environment and urban and industrial areas, are shown in artworks such as photographs, paintings, and (multimedia) installations. This is of course in line with the historical origins of the subject-matter. However, while explorers enjoy physically visiting areas of urban and industrial decay, only very few of them would go to a large-scale devastated area such as an oil field, an open-cast mine or a poisonously flooded area to experience it physically (Kover 2014). How can we account for these different attitudes?
description: Everydayness. Contemporary Aesthetic Approaches
Amtliche Mitteilungen der Technischen Universität Dortmund Nr. 24/2021
Creators: name: (:Unkn) Unknown
Publisher: name: Technische Universität Dortmund
Year: 2021
Subjects: subject: 080

description: Geschäftsordnung des Hochschulrats der Technischen Universität Dortmund vom 11. November 2021
description: Amtliche Mitteilungen der Technischen Universität Dortmund;2021;24
Non-Hysteretic Condition in Negative Capacitance Junctionless FETs
Creators: name: Rassekh, Amin
name: Jazaeri, Farzan
name: Sallese, Jean-Michel
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: This paper analyzes the design space stability of negative capacitance double gate junctionless FETs (NCDG JLFET). Using analytical expressions derived from a charge-based model, we predict instability condition, hysteresis voltage, and critical thickness of the ferroelectric layers giving rise to the negative capacitance behavior. The impact of the technological parameters is investigated in order to ensure hysteresis-free operation. Finally, the stability of NCDG JLFET is predicted over a wide range of temperatures from 77K to 400K. This approach has been assessed with numerical TCAD simulations.
A Hybrid Optimization Method Combining Network Expansion Planning and Switching State Optimization
Creators: Florian Schäfer
Alexander Scheidler
and Martin Braun
Publisher: name: IEEE
Year: 2020

In this paper, we develop a hybrid optimization method to solve the combined optimization of switching state optimization and network expansion planning.
Combining switching state optimization (SSO) and network expansion planning (NEP) in AC systems results in a mixed-integer non-linear optimization problem. Two methodically different solution approaches are mathematical programming and heuristic methods. In this paper, we develop a hybrid optimization method combining both methods to solve the combined optimization of SSO and NEP. The presented hybrid method applies a DC programming model as an initialization strategy to reduce the search space of the heuristic. A greedy heuristic ensures that the obtained solutions are AC feasible. We compare the hybrid method with other heuristic methods and three mathematical programming models on the same set of planning problems. We show optimization results for four realistic sized power system study cases. Evaluation criteria are convergence, solution cost, and run time. Results show that the hybrid method is able to find a higher number of valid AC-solutions in comparisons to the mathematical programming methods. Furthermore, the obtained solutions have lower expansions costs and are obtained in a shorter run-time compared to the remaining methods for the analyzed study cases. As an addition to this paper, the hybrid implementation and the defined benchmark cases are available as open-source software.
Static Power Converters of 500 kW or Less Serving as the Relay Interface Package for Non-Conventional Generators
Creators: Working Group C-5 Static Power Converter Serving As Interface Package
Publisher: name: IEEE
Year: 1993

This special publication was prepared by the Power System Relaying Committee of the IEEE to assist people involved in the installation, application, and operation of utility-interconnected dispersed storage and generation (DSG) systems of 500 kW or less.
This special publication was prepared by the Power System Relaying Committee of the IEEE to assist people involved in the installation, application, and operation of utility-interconnected dispersed storage and generation (DSG) systems of 500 kW or less.
A Novel Disaster Image Dataset and Characteristics Analysis using Attention Model
Creators: name: Niloy, Fahim Faisal
name: Arif
name: Nayem, Abu Bakar Siddik
name: Sarker, Anis
name: Paul, Ovi
name: Amin, M. Ashraful
name: Ali, Amin Ahsan
name: Zaber, Moinul Islam
name: Rahman, AKM Mahbubur
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: The advancement of deep learning technology has enabled us to develop systems that outperform any other classification technique. However, success of any empirical system depends on the quality and diversity of the data available to train the proposed system. In this research, we have carefully accumulated a relatively challenging dataset that contains images collected from various sources for three different disasters: fire, water and land. Besides this, we have also collected images for various damaged infrastructure due to natural or man made calamities and damaged human due to war or accidents. We have also accumulated image data for a class named non-damage that contains images with no such disaster or sign of damage in them. There are 13,720 manually annotated images in this dataset, each image is annotated by three individuals. We are also providing discriminating image class information annotated manually with bounding box for a set of 200 test images. Images are collected from different news portals, social media, and standard datasets made available by other researchers. A three layer attention model (TLAM) is trained and average five fold validation accuracy of 95.88% is achieved. Moreover, on the 200 unseen test images this accuracy is 96.48%. We also generate and compare attention maps for these test images to determine the characteristics of the trained attention model. Our dataset is available at https://niloy193.github.io/Disaster-Dataset
description: ICPR 2020
Analisi hot-spot termica estiva dell'Area Metropolitana di Firenze: il ruolo delle caratteristiche urbane locali
Creators: name: Guerri, Giulia
name: Crisci, Alfonso
name: Morabito, Marco
Publisher: name: Zenodo
Year: 2021
Subjects: Isola di calore urbana
Temperatura superficiale
Analisi termica Hot-spot
Strategie di mitigazione urbana
Vegetazione
Consumo di suolo

description: Report sintetico dell'articolo scientifico pubblicato sulla rivista Remote Sensing (https://www.mdpi.com/2072-4292/13/3/538) contenente gli elaborati cartografici che saranno utilizzati a supporto del primo Piano del Verde del Comune di Firenze. Nel report sono descritte le finalità, originalità, vantaggi e target della ricerca effettuata, nonché le fasi della ricerca. Sono descritte e mostrate in dettaglio tutte le caratteristiche (finalità, periodo di analisi, fonte dei dati, risoluzione spaziale, metodo di analisi) degli elaborati cartografici sviluppati.
Rare-event properties in a classical stochastic model describing the evolution of random unitary circuits
Creators: name: de Queiroz, S. L. A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We investigate the statistics of selected rare events in a (1+1)-dimensional (classical) stochastic growth model which describes the evolution of (quantum) random unitary circuits. In such classical formulation, particles are created and/or annihilated at each step of the evolution process, according to rules which generally favor a growing cluster size. We apply a large-deviation approach based on biased Monte Carlo simulations, with suitable adaptations, to evaluate (a) the probability of ending up with a single particle at a specified final time $t_f$, and (b) the probability of having particles outside the light cone, defined by a "butterfly velocity" $v_B$, at $t_f$. Morphological features of single-particle final configurations are discussed, in connection with whether the location of such particle is inside or outside the light cone; we find that joint occurrence of both events of types (a) and (b) drives significant changes to such features, signalling a second-order phase transition.
description: 11 pages, 12 figures
MeerKAT Primary Beam Measurements in the L Band
Creators: name: de Villiers, Mattieu
name: Cotton, William
Publisher: name: arXiv
Year: 2022
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Full-polarization primary beam patterns of MeerKAT antennas have been measured in L-band (856 to 1711 MHz) by means of radio holography using celestial targets. This paper presents the observed frequency dependent properties of these beams, and guides users of this 64 antenna radio telescope that are concerned by its direction dependent polarization effects. In this work the effects on the primary beams due to modeling simplifications, bandwidth averaging, gravitational loading and ambient temperature are quantified within the half power region of the beam. A perspective is provided on the level of significance of typical use case effects. It is shown that antenna pointing is a leading cause of inaccuracy for telescope users in the presumed beam shape, introducing errors exceeding 1% in power near the half power point of beams, owing to a telescope pointing accuracy of $σ\approx 0.6$ arcminutes. Disregarding these pointing errors, variability in the Stokes I beam shape relative to the array average is most commonly around 0.3% in power; however, the impact above 1500 MHz is on average triple that of the lower half of the band. This happens because the proportion of higher order waveguide modes that are activated and propagate is sensitive to small manufacturing differences in the orthomode transducer for each receiver. Primary beam correction verification test results for an off-axis spectral index measurement experiment are included.
description: 21 pages, 16 figures, 3 tables
Core Formation in High-z Massive Haloes: Heating by Post Compaction Satellites and Response to AGN Outflows
Creators: name: Dekel, Avishai
name: Freundlich, Jonathan
name: Jiang, Fangzhou
name: Lapiner, Sharon
name: Burkert, Andreas
name: Ceverino, Daniel
name: Du, Xiaolong
name: Genzel, Reinhard
name: Primack, Joel
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Observed rotation curves in star-forming galaxies indicate a puzzling dearth of dark matter in extended flat cores within haloes of mass $\geq\! 10^{12}M_\odot$ at $z\!\sim\! 2$. This is not reproduced by current cosmological simulations, and supernova-driven outflows are not effective in such massive haloes. We address a hybrid scenario where post-compaction merging satellites heat up the dark-matter cusps by dynamical friction, allowing AGN-driven outflows to generate cores. Using analytic and semi-analytic models (SatGen), we estimate the dynamical-friction heating as a function of satellite compactness for a cosmological sequence of mergers. Cosmological simulations (VELA) demonstrate that satellites of initial virial masses $>\!10^{11.3}M_\odot$, that undergo wet compactions, become sufficiently compact for significant heating. Constituting a major fraction of the accretion onto haloes $\geq\!10^{12}M_\odot$, these satellites heat-up the cusps in half a virial time at $z\!\sim\! 2$. Using a model for outflow-driven core formation (CuspCore), we demonstrate that the heated dark-matter cusps develop extended cores in response to removal of half the gas mass, while the more compact stellar systems remain intact. The mergers keep the dark matter hot, while the gas supply, fresh and recycled, is sufficient for the AGN outflows. AGN indeed become effective in haloes $\geq\!10^{12}M_\odot$, where the black-hole growth is no longer suppressed by supernovae and its compaction-driven rapid growth is maintained by a hot CGM. For simulations to reproduce the dynamical-friction effects, they should resolve the compaction of the massive satellites and avoid artificial tidal disruption. AGN feedback could be boosted by clumpy black-hole accretion and clumpy response to AGN.
description: 25+10 pages, 10+8 figures
Engineering Giant Nonlinearities in Quantum Nanosystems
Creators: name: Jacobs, Kurt
name: Landahl, Andrew
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We describe a method to engineer giant nonlinearities in, and probes to measure nonlinear observables of, mesoscopic quantum resonators. This involves tailoring the Hamiltonian of a simple auxiliary system perturbatively coupled to the resonator, and has the potential to engineer a wide range of nonlinearities to high accuracy. We give a number of explicit examples, including a readily realizable two-qubit auxiliary system that creates an x^4 potential and a Chi^(3) (Kerr) nonlinearity, valid to fifth-order in the perturbative coupling.
description: 4 pages, retex4; v2: published version, improved and compactified presentation
SARIQ – YASHIL (XANTHOPHYTA) BO'LIMINING TAVSIFI, SISTEMATIKASI, TARQALISHI VA AHAMIYATI
Creators: name: Odilov, Odiljon
Publisher: name: Zenodo
Year: 2025

description: Bu tezisda sariq – yashil (Xanthophyta) bo’limining asosiy vakillari tuzilishi, ko’payishi, xilma xilligi va  ularni tabiatdagi ahamiyati haqida batafsil ma’lumotlar berilgan.
Navigating ultrasmall worlds in ultrashort time
Creators: name: Boguna, Marian
name: Krioukov, Dmitri
Publisher: name: arXiv
Year: 2008
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Networking and Internet Architecture (cs.NI)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Random scale-free networks are ultrasmall worlds. The average length of the shortest paths in networks of size N scales as lnlnN. Here we show that these ultrasmall worlds can be navigated in ultrashort time. Greedy routing on scale-free networks embedded in metric spaces finds paths with the average length scaling also as lnlnN. Greedy routing uses only local information to navigate a network. Nevertheless, it finds asymptotically the shortest paths, a direct computation of which requires global topology knowledge. Our findings imply that the peculiar structure of complex networks ensures that the lack of global topological awareness has asymptotically no impact on the length of communication paths. These results have important consequences for communication systems such as the Internet, where maintaining knowledge of current topology is a major scalability bottleneck.
description: 4 pages, 2 figures
A study investigating the themes of children’s play after major heart surgery
Creators: name: Ralston, Marjory
Publisher: name: University of British Columbia
Year: 2010

description: This study was designed to gather information about the nature and content of post-surgical play behaviour displayed by hospitalized pre-school children. Four questions were explored: Are common themes expressed in the play behaviour of hospitalized pre-school children after major surgery? Does the quality and intensity of the play behaviour demonstrated by pre-school children follow a similar pattern? Will pre-school children use play therapy as a medium through which to express fears and concerns about their hospital experience? Do children tend to act out their perceptions of what has happened to them in hospital? The population selected for the study were four girls and one boy between the ages of three and five years, who were admitted for major surgery on the heart or great vessels. During the recovery period after surgery each child had the opportunity to take part in at least five play therapy sessions lasting approximately one hour each. Play therapy took the form of situational play using real or simulated hospital equipment and various dolls representing children and adults. Each child chose the direction and content of play. The investigator took part in play as directed by the child. Parents could join in if they wished. The verbal and non-verbal behaviour displayed by each child during play therapy was recorded by audio tape and by process recordings. Four out of five children in the study participated actively in play therapy. In the course of play they expressed five common themes: intrusive procedures; re-enactment of procedures; testing reality; autonomy: regaining control; separation from home and family; and nurturing activities. The quality and intensity of the children's play behaviour followed a pattern from intense to more relaxed and from aggressive to more gentle play. During play each child expressed some individual fears and concerns about his hospitalization. Intrusive procedures were the most frequent topic of play for all the children. Finally, each child tended to act through specific procedures so that play behaviour became a factual account of the child's hospital experience. One child, the only boy in the study, did not want to participate in play therapy. The reasons for this were not investigated. It was concluded that play therapy is a useful technique which can assist nurses understand the pre-school child's perception of his hospital experience. Play therapy also has potential as a therapeutic intervention to help a child come to terms with the traumatic events of his hospitalization.
Lipophilic nucleosides: studies toward self-assembled functional materials
Creators: name: Gramigna, Lucia <1986>
Publisher: name: Alma Mater Studiorum - Università di Bologna
Year: 2014
Subjects: CHIM/06 Chimica organica

description: Molecular self-assembly takes advantage of supramolecular non-covalent interactions (ionic, hydrophobic, van der Waals, hydrogen and coordination bonds) for the construction of organized and tunable systems. In this field, lipophilic guanosines can represent powerful building blocks thanks to their aggregation proprieties in organic solvents, which can be controlled by addition or removal of cations. For example, potassium ion can template the formation of piled G-quartets structures, while in its absence ribbon-like G aggregates are generated in solution.
In this thesis we explored the possibility of using guanosines as scaffolds to direct the construction of ordered and self-assembled architectures, one of the main goals of bottom-up approach in nanotechnology. In Chapter III we will describe Langmuir-Blodgett films obtained from guanosines and other lipophilic nucleosides, revealing the “special” behavior of guanine in comparison with the other nucleobases. In Chapter IV we will report the synthesis of several thiophene-functionalized guanosines and the studies towards their possible use in organic electronics: the pre-programmed organization of terthiophene residues in ribbon aggregates could allow charge conduction through π-π stacked oligothiophene functionalities. The construction and the behavior of some simple electronic nanodevices based on these organized thiopehene-guanosine hybrids has been explored.
Fast Frequency Support From Wind Turbine Systems by Arresting Frequency Nadir Close to Settling Frequency
Creators: Xianxian Zhao
Ying Xue
and Xiao-Ping Zhang
Publisher: name: IEEE
Year: 2020

This paper proposes a fast frequency support scheme for wind turbine systems (WTSs) that can enable frequency nadir to be significantly raised and close to the settling frequency and eliminate frequency second dip.
The recent power cut incident in the UK on 9th August 2019 indicated that frequency control to raise frequency nadir and eliminate frequency second dip is highly desirable for power grids with high penetration of wind energy. This paper proposes a fast frequency support scheme for wind turbine systems (WTSs) that can enable frequency nadir to be significantly raised and close to the settling frequency and eliminate frequency second dip. In the proposed frequency support scheme, in order to achieve similar frequency support performance and ensure stability of WTSs under varying wind speeds, different levels of wind power penetration and system conditions, an adaptive gain, which is a function of real-time rotor speed and wind power penetration level, is proposed. In the proposed scheme, rotor speeds of WTSs are proposed not to be recovered to the optimal operating points during the primary frequency control, but recovered during the secondary frequency control. Simulation results on the IEEE two-area power system with a doubly fed induction generator (DFIG)-based wind farm and the IEEE 39-bus power system with permanent magnetic synchronous generator (PMSG)-based wind farms using real-time digital simulator (RTDS) and Dymola are presented to verify the effectiveness of the proposed scheme.
title: Front Matter, Table of Contents, Preface, Organization, List of Authors
Creators: name: Chatzigiannakis, Ioannis
name: Indyk, Piotr
name: Kuhn, Fabian
name: Muscholl, Anca
Publisher: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Year: 2017
Subjects: subject: Front Matter
subject: Table of Contents
subject: Preface
subject: Organization
subject: List of Authors

description: Front Matter, Table of Contents, Preface, Organization, List of Authors
description: LIPIcs, Vol. 80, 44th International Colloquium on Automata, Languages, and Programming (ICALP 2017), pages 0:i-0:xlii
Active System Grounding With a Novel Distribution Transformer Design
Creators: Michael D. Everton
Publisher: name: IEEE
Year: 2020

A novel Wye-wye transformer design for active system grounding, is described in this paper.
A novel Wye-wye transformer design for active system grounding, is described in this paper. Proposed as a solution to improve the ground fault performance in distribution line networks, the zero-sequence flux developed in the magnetic core of a transformer is on a ground fault harvested by coils wound around three limbs, or extra limb(s) in a Wye-wye transformer. Built with three limbs, and no tertiary winding, the flux developed in the core on a ground fault is forced to return through air, which has a high reluctance, but with four or more limbs, the flux circulates in the transformer magnetic core, which has a low reluctance. Connected to one or more single-phase windings, the transformer neutral current is on a ground fault actively altered by fixed and switched load impedances. In theory, a ground fault arc is with a low current and delay in recovery voltage self-extinguishing, and no interruption in supply is required, but sustained, must be isolated. Proposed in this paper, for an active load switched grounding method, the neutral current on a sustained ground fault is increased to enable plain overcurrent and fuse protection to operate without the need of sensitive directional relay protection.
The structure and stability of massive hot white dwarfs
Creators: name: Nunes, Sílvia P.
name: Arbañil, José D. V.
name: Malheiro, Manuel
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We investigate the structure and stability against radial oscillations, pycnonuclear reactions, and inverse $β$-decay of hot white dwarfs. We regard that the fluid matter is made up for nucleons and electrons confined in a Wigner-Seitz cell surrounded by free photons. It is considered that the temperature depends on the mass density considering the presence of an isothermal core. We find that the temperature produces remarkable effects on the equilibrium and radial stability of white dwarfs. The stable equilibrium configuration results are compared with white dwarfs estimated from the Extreme Ultraviolet Explorer Survey and Sloan Digital Sky Survey. We derive masses, radii, and central temperatures for the most massive white dwarfs according to surface gravity and effective temperature reported by the survey. We note that these massive stars are in the mass region where the general relativity effects are important. These stars are near the threshold of instabilities due to radial oscillations, pycnonuclear reaction, and inverse $β$-decay. Regarding the radial stability of these stars as a function of the temperature, we obtain that the radial stability decreases with the increment of central temperature. We also obtain that the maximum mass point and the zero eigenfrequencies of the fundamental mode are determined at the same central energy density. Regarding low-temperature stars, the pycnonuclear reactions occur in almost similar central energy densities, and the central energy density threshold for inverse $β$-decay is not modified. For $T_c\geq1.0\times10^{8}\,[\rm K]$, the onset of the radial instability is attained before the pycnonuclear reaction and the inverse $β$-decay.
description: To appear in the Astrophysical Journal
Towards Centrifugal Compressor Stages Virtual Testing
Creators: name: Guidotti, Emanuele <1977>
Publisher: name: Alma Mater Studiorum - Università di Bologna
Year: 2014
Subjects: ING-IND/08 Macchine a fluido

description: Flow features inside centrifugal compressor stages are very complicated to simulate with numerical tools due to the highly complex geometry and varying gas conditions all across the machine. For this reason, a big effort is currently being made to increase the fidelity of the numerical models during the design and validation phases. Computational Fluid Dynamics (CFD) plays an increasing role in the assessment of the performance prediction of centrifugal compressor stages. Historically, CFD was considered reliable for performance prediction on a qualitatively level, whereas tests were necessary to predict compressors performance on a quantitatively basis. In fact "standard" CFD with only the flow-path and blades included into the computational domain is known to be weak in capturing efficiency level and operating range accurately due to the under-estimation of losses and the lack of secondary flows modeling. This research project aims to fill the gap in accuracy between "standard" CFD and tests data by including a high fidelity reproduction of the gas domain and the use of advanced numerical models and tools introduced in the author's OEM in-house CFD code. In other words, this thesis describes a methodology by which virtual tests can be conducted on single stages and multistage centrifugal compressors in a similar fashion to a typical rig test that guarantee end users to operate machines with a confidence level not achievable before. Furthermore, the new "high fidelity" approach allowed understanding flow phenomena not fully captured before, increasing aerodynamicists capability and confidence in designing high efficiency and high reliable centrifugal compressor stages.
Hardware-in-the-Loop Testing of Dynamic Grid Voltages for Static Var Compensator Controllers With Single-Phase Induction Motor Loads
Creators: Bikrant Poudel
Ebrahim Amiri
Jayanth R. Ramamurthy
Ittiphong Leevongwat
Thomas E. Field
Rastin Rastgoufard
and Parviz Rastgoufard
Publisher: name: IEEE
Year: 2020

This paper investigates the interaction between two Static var Compensators (SVCs) to verify dynamic grid voltage support is maintained and that the SVC controllers do not negatively interact with each other.
This paper investigates the interaction between two Static var Compensators (SVCs) to verify dynamic grid voltage support is maintained and that the SVC controllers do not negatively interact with each other. For this purpose, the controls of the SVCs with all of the remotely controlled Mechanically-Switched Capacitors (MSCs) have been tested in a closed-loop real-time simulator environment using SVC replicas (physical controllers) of the actual field installations. To accurately capture the power system's response to phenomenon such as potential Fault Induced Delayed Voltage Recovery (FIDVR), the dynamics of the generators and the motor loads are modeled in the simulations. A hybrid model consisting of real and reactive power (P-Q) loads and aggregated motor load of a single-phase induction motor suitable for three-phase time-domain simulation was developed and connected to the power system. The developed aggregate motor load model includes details such as the main winding, auxiliary winding, starting capacitor, motor inertia, and distribution transformers. It is observed that dynamic grid voltage support can be maintained and the SVC controllers do not negatively interact with each other if all the SVC control blocks are enabled and function normally.
Impact of Energy Storage on Economic Dispatch of Distribution Systems: A Multi-Parametric Linear Programming Approach and Its Implications
Creators: Wei Wei
Danman Wu
Zhaojian Wang
Shengwei Mei
and João P. S. Catalão
Publisher: name: IEEE
Year: 2020

This paper aims to characterize the impact of energy storage unit on the economic operation of distribution systems in a geometric manner that is convenient for visualization.
As a main flexible resource, energy storage helps smooth the volatility of renewable generation and reshape the load profile. This paper aims to characterize the impact of energy storage unit on the economic operation of distribution systems in a geometric manner that is convenient for visualization. Posed as a multi-parametric linear programming problem, the optimal operation cost is explicitly expressed as a convex piecewise linear function in the MW/MWh parameter of the energy storage unit. Based on duality theory, a dual linear programming based algorithm is proposed to calculate an approximate optimal value function (OVF) and critical regions, circumventing the difficulty of degeneracy, a common challenge in the existing multi-parametric linear programming solvers. When the uncertainty of renewable generation is considered, the expected OVF can be readily established based on OVFs in the individual scenarios, which is scalable in the number of scenarios. The OVF delivers abundant sensitivity information that is useful in energy storage sizing. Leveraging the OVFs, a robust stochastic optimization model is proposed to determine the optimal MW-MWh size of the storage unit subject to a given budget, which gives rise to a simple linear program. Case study provides a clear sketch of the outcome of the proposed method, and suggests that the optimal energy-power ratio of an energy storage unit is between 5 and 6 from the economical perspective.
Maintenance Good Practices for Nuclear Power Plant Electrical Equipment
Creators: Working Group 3.3 - Maintenance Good Practices
Publisher: name: IEEE
Year: 1988

This paper is Part 1 of a work-in-progress report which represents work being performed by an IEEE working group. Motor maintenance is addreessed by a variety of industry standards, utility procedures and manufacturer instructions, as well as by recently published assessments of nuclear and non-nuclear operating experience and motor reliability data. Nuclear utilities must select effective maintenance practices from these sources, while giving due consideration to their own particular experience. In this paper, good practices for preventive maintenance of motors are recommended which address the most frequent causes of motor failures. Due to the large number of critical motors installed in a nuclear generating station, the problem of prioritizing motors for preventive maintenance has been addressed in Part 2, a companion paper.
This paper is Part 1 of a work-in-progress report which represents work being performed by an IEEE working group. Motor maintenance is addreessed by a variety of industry standards, utility procedures and manufacturer instructions, as well as by recently published assessments of nuclear and non-nuclear operating experience and motor reliability data. Nuclear utilities must select effective maintenance practices from these sources, while giving due consideration to their own particular experience. In this paper, good practices for preventive maintenance of motors are recommended which address the most frequent causes of motor failures. Due to the large number of critical motors installed in a nuclear generating station, the problem of prioritizing motors for preventive maintenance has been addressed in Part 2, a companion paper.
Mosaic Packing to Visualize Large-Scale Electric Grid Data
Creators: Adam B. Birchfield and Thomas J. Overbye
Publisher: name: IEEE
Year: 2020

This paper describes a new visualization technique that draws a mosaic of colored tiles to represent multiple data fields for electric grid objects, arranged to preserve geographic context.
For large power systems, a continual challenge is to display wide-area data in a way that maximizes human users' situational awareness. This paper describes a new visualization technique that draws a mosaic of colored tiles to represent multiple data fields for electric grid objects, arranged to preserve geographic context. The key problem in creating these diagrams is packing the tiles onto the display space, minimizing the total displacement while forbidding overlaps. This paper formulates that problem and presents a horizontal-packing algorithm which is able to produce a feasible, quality solution at an interactive time scale. Illustrative examples are shown for using mosaics to monitor wide-area generator status and dispatch, bus voltages, and line and transformer limits. Mosaics can be customized in numerous ways to show different aspects of the system state, providing for human users a simultaneous sense of the wide-area summary, regional trends, and prominent outliers.
Online Coordination of Plugged-In Electric Vehicles and Optimal Rescheduling of Switched Shunt Capacitors in Smart Grid Considering Battery Charger Harmonics
Creators: Sara Deilami
Publisher: name: IEEE
Year: 2018

PES Open Access Paper
This paper presents a practical solution to improve the performance and power quality of the smart grid (SG) with a high penetration of plugged-in electric vehicles (PEVs). The random, mobile, and time-variant PEV demands can overload lines, transformers, and distributed generations while the collective impacts of their battery charger harmonics may increase the overall total harmonic distortion (THD) of SG. To overcome these issues, this paper incorporates the optimal rescheduling of switched shunt capacitors (SSCs) and their day-ahead schedules in a recently developed online maximum sensitivity selection-based PEV coordination algorithm with the inclusion of harmonics. This will not only improve customer satisfaction by fully charging all vehicles before 8 A.M. for the next day travel but also reduce node voltage fluctuations, overall THD, and system losses. To check the performance of the proposed approach, detailed simulations are performed on the modified IEEE 23-kV medium voltage distribution network with seven SSCs and 22 low-voltage residential networks that are populated with PEVs with nonlinear battery chargers and industry nonlinear loads.
eT&D 2017
Creators: PES Members
Publisher: name: IEEE
Year: 2017

Proceedings from eT&D 2017
The 2nd IEEE Workshop on Electronic Power Transmission and Distribution (eT&D 2017), jointly sponsored by IEEE Power Electronics Society (PELS) and IEEE Power & Energy Society (PES), was held on November 7-8, at Aalborg, Denmark, where a 100% renewable energy future by 2050 is targeted. This international workshop features proceedings only (without presentations). Stability, power quality and resiliency of power electronic power grids will be of prime interest in eT&D 2017.
Preview of the Revised IEEE 1547 Standard for Interconnecting Distributed Energy Resources with Electric Power Systems
Creators: B. Enayati
Publisher: name: IEEE
Year: 2018

Technical Report
This presentation provides an overview of the 1547 standard for the interconnection and interoperability of distributed energy resources (DER) with electric power systems (EPS). It reviews requirements relevant to the interconnection and interoperability performance, operation, and testing, and, safety, maintenanceand security considerations.
Organizational issues in community mental health administration
Creators: name: Turner, R. David
Publisher: name: University of British Columbia
Year: 2010

description: The dissertation discusses the provision and organization of mental health services through the operation of Community Mental Health Centres outside the Greater Vancouver area in the Province of B.C.. A derived organizational structure of a CMHC is presented permitting a generalizable discussion of inter- and intra-organizational features and their relationship to administration peculiar to this organization. A number of propositions are generated regarding CMHC organizational structure and process; these propositions are based on the dimensions identified in the areas of organizational technology, environment and goals. The propositions are applied to a model of management permitting an examination of general areas of management concern. Methods of optimizing these areas are discussed operationally with the intent of facilitating organizational effectiveness in a CMHC.
Effects of V2H Integration on Optimal Sizing of Renewable Resources in Smart Home Based on Monte Carlo Simulations
Creators: Bahman Naghibi
Mohammad A. S. Masoum
and Sara Deilami
Publisher: name: IEEE
Year: 2018

PES Open Access Paper
This paper investigates optimal sizing of rooftop PV, wind turbine (WT), and battery storage system (BSS) in smart home (SH) with a plug-in electric vehicle (PEV) considering vehicle-to-home (V2H) and home-to-grid operations. The proposed idea is to use a rule-based home energy management system (HEMS) along with the Monte Carlo simulations and particle swarm optimization to find the optimal sizes of renewable resources and BSS by minimizing the annual cost of household electricity. The probabilistic behaviors of wind speed, irradiance, temperature, load and electricity rate, as well as the availability of PEV are considered for the input data generation. Detailed simulations and sensitivity analyses are performed to investigate the impacts of shiftable loads, V2H integration, battery charge/discharge rates, designated maximum daily export energy and maximum PV, and WT and battery capacity limits on the annual and levelized costs of electricity. Our analyses reveal the possibility of eliminating BSS altogether in SH with PEV with some reduction in annual electricity cost.
Parallel-in-Time Object-Oriented Electromagnetic Transient Simulation of Power Systems
Creators: Tianshi Cheng
Tong Duan
and Venkata Dinavahi
Publisher: name: IEEE
Year: 2020

This paper proposes a system-level parallel-in-time EMT simulation method based on traditional nodal analysis and the Parareal algorithm.
Parallel-in-time methods are emerging to accelerate the solution of time-consuming problems in different research fields. However, the complexity of power system component models brings challenges to realize the parallel-in-time power system electromagnetic transient (EMT) simulation, including the traveling wave transmission lines. This paper proposes a system-level parallel-in-time EMT simulation method based on traditional nodal analysis and the Parareal algorithm. A new interpretation scheme is proposed to solve the transmission line convergence problem. To integrate different kinds of traditional EMT models, a component-based EMT system solver architecture is proposed to address the increasing model complexity. An object-oriented C++ implementation is proposed to realize the parallel-in-time Parareal algorithm based on the proposed architecture. The results on the IEEE-118 test system show 2.30x speed-up compared to the sequential algorithm under the same accuracy with 6 CPU threads, and a high parallel efficiency around 40%. The performance comparison of various IEEE test cases shows that the system's time-domain characteristics determine the speed-up of Parareal algorithm, and the delays in transmission lines significantly affect the performance of parallel-in-time power system EMT simulations.
Analysis and Modeling of Eddy-Current Couplings for Auxiliary Power Generation on a Freight Train Wagon
Creators: Michael Flankl
Arda Tuysuz
Cheng Gong
Tibor Stolz
and Johann W. Kolar
Publisher: name: IEEE
Year: 2018

PES Open Access Paper
The subject of this paper is a non-coaxial eddy-current coupling, which can be utilized on a freight train wagon for generating auxiliary power in the range of several Watts. The coupling comprises a wheel with radially magnetized permanent magnets, which is positioned in the vicinity of the wagon's wheel, and extracts kinetic energy when the train is in motion. A computational method for solving the 3-D problem of the eddy-current coupling is presented. Maxwell's equations for calculating the excited eddy currents are solved in the Fourier domain with a semi-analytical method (SAM), resulting in computationally efficient simulations. In a case study, the SAM shows 500 times faster simulation times, compared to a 3-D transient eddy-current finite-element method simulation, carried out with a commercially available software. The SAM is verified with measurements taken on two hardware prototypes. Furthermore, in order to generalize the study, a ??-Pareto optimization of the system is conducted for relaxed design space boundaries, an output power of P = 10 W, a C45E steel wheel with v = 80 km/h surface velocity, and g = 3 mm air gap. It is shown that a power density up to 0.8 kW/dm3 (13 W/in3) and a transfer efficiency up to 60% can be achieved using the proposed system.