scholarly journals Printed detector bands for measurements of strain in core interior of transformers

2018 ◽  
Vol 69 (6) ◽  
pp. 481-484
Author(s):  
Georgi Shilyashki ◽  
Helmut Pfützner ◽  
Andreas Windischhofer ◽  
Gerald Trenner ◽  
Markus Giefing
Keyword(s):  
Environmental Awareness ◽  
High Sensitivity ◽  
The Core ◽  
Plane Normal ◽  
First Results ◽  
Local Measurements ◽  
First Time ◽  
Very High

Abstract In the recent years, the reducing of audible noise of laminated machine cores has become great importance, due to high relevance given to environmental awareness. The strain caused by magnetostriction and magnetostatic forces is recognized as one of the main sources of noise. Especially for transformers, strain in the core interior tends to be different from that on the surface, due to differences of clamping, variation of in-plane fluxes and pronounced off-plane (normal) fluxes. For the first time, local measurements of strain in the core interior are presented by means of a novel printed detector band. First results tend to be very promising, exhibiting very high sensitivity and resolution. So far, the relevance of measurements is restricted to comparisons of different core regions.

Electroionization study of ethylene: ionization and appearance energies, ion-pair formations, and negative ions

1987 ◽  
Vol 65 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Pierre Plessis ◽  
Paul Marmet
Keyword(s):  
Electron Impact ◽  
Negative Ions ◽  
High Sensitivity ◽  
Ion Pair ◽  
Common Mechanism ◽  
Threshold Region ◽  
Monoenergetic Electron ◽  
Text Fragment ◽  
First Time ◽  
Very High

Monoenergetic electron-impact threshold ionization and appearance curves of very high sensitivity of ethylene and all fragments containing at least one carbon atom are analyzed in detail. Ionization or appearance energies are measured for all ions, including the [Formula: see text] fragment. Structures are observed in the immediate [Formula: see text] threshold region, which are attributed to hot bands and to Rydberg autoionizing states. [Formula: see text],[Formula: see text] and [Formula: see text] ion-pair formations are reported for the first time. Simultaneous production of positive and negative ions is seen to be a common mechanism by electron impact. Appearance energies of some fragments are several electron volts lower than those of previous works.

Electronic Structure and Mechanical Properties of Intermetallics: Apb Energies in Ni-Al-Based Systems

1988 ◽  
Vol 133 ◽  
Author(s):  
Tao Hong ◽  
A. J. Freeman
Keyword(s):  
Model Systems ◽  
Simplified Model ◽  
Interface Plane ◽  
Energy Contribution ◽  
Self Consistent ◽  
First Results ◽  
High Degree ◽  
First Time ◽  
B2 Structure ◽  
Very High

ABSTRACTThe possible origin of the high degree of brittleness (i.e., low ductility) of the Ni-Al-based alloys in the B2 structures is investigated by means of all-electron self-consistent total energy LMTO calculations. Using a supercell approach, the energetics of the two simplest anti-phase boundaries (APB) for NiAl in the B2 structure - namely the ½<111> on {110} and ½<111> on {112} - are calculated for the first time assuming no relaxation at the interface. We find APB energies of order of 800 ergs/cm2 for both cases. Since the calculated APB energies are very high, <111> slip is hardly likely to occur - as suggested experimentally. By substituting Ni or Al with V, Cr or Mn at the APB interface plane, remarkably decreased APB energies are obtained. These first results on these simplified model systems may suggest a way to decrease the APB energy contribution to the ductility of NiAl-based alloys.

Dewey and Environmental Philosophy

2017 ◽  
pp. 712-732
Author(s):  
Paul B. Thompson ◽  
Zachary Piso
Keyword(s):  
Environmental Justice ◽  
Environmental Awareness ◽  
Environmental Philosophy ◽  
Environment Interaction ◽  
Human Control ◽  
The Core ◽  
Environmental Pragmatism

Though environmental philosophers trace the roots of environmental awareness to the decades of John Dewey’s prominence, Dewey himself was conspicuously mum about the environmental controversies of his day. A Deweyan environmental pragmatism, then, must find sustenance in less prosaically environmental themes of the American philosopher’s project. This chapter attends to Dewey’s notion of organism-environment interaction, which is at the core of Dewey’s understanding of experience and which informs Dewey’s philosophy from epistemology to aesthetics. The chapter stresses that Dewey’s notion of organism-environment interaction is an account of how organisms dynamically respond to changes in their environment. However, contrary to several misinterpretations of environmental pragmatism, this dynamic responsiveness is not a call for human control over nature. Indeed, we conclude that an environmental philosophy oriented by Dewey’s notion of organism-environment interaction provides promising approaches to interdisciplinarity, transdisciplinarity, and environmental justice.

scholarly journals Shell-crossing in a ΛCDM Universe

2020 ◽  
Vol 501 (1) ◽  
pp. L71-L75
Author(s):  
Cornelius Rampf ◽  
Oliver Hahn
Keyword(s):  
Dark Matter ◽  
Perturbation Theory ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Three Dimensional ◽  
Random Initial Data ◽  
Recursion Relations ◽  
Indispensable Tool ◽  
First Time ◽  
Very High

ABSTRACT Perturbation theory is an indispensable tool for studying the cosmic large-scale structure, and establishing its limits is therefore of utmost importance. One crucial limitation of perturbation theory is shell-crossing, which is the instance when cold-dark-matter trajectories intersect for the first time. We investigate Lagrangian perturbation theory (LPT) at very high orders in the vicinity of the first shell-crossing for random initial data in a realistic three-dimensional Universe. For this, we have numerically implemented the all-order recursion relations for the matter trajectories, from which the convergence of the LPT series at shell-crossing is established. Convergence studies performed at large orders reveal the nature of the convergence-limiting singularities. These singularities are not the well-known density singularities at shell-crossing but occur at later times when LPT already ceased to provide physically meaningful results.

scholarly journals On the formation and stability of fermionic dark matter halos in a cosmological framework

2020 ◽  
Author(s):  
Carlos R Argüelles ◽  
Manuel I Díaz ◽  
Andreas Krut ◽  
Rafael Yunis
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Space Distribution ◽  
Coarse Grained ◽  
Dark Matter Halos ◽  
The Core ◽  
The Galaxy ◽  
Gravitating Systems ◽  
The Given ◽  
First Time

Abstract The formation and stability of collisionless self-gravitating systems is a long standing problem, which dates back to the work of D. Lynden-Bell on violent relaxation, and extends to the issue of virialization of dark matter (DM) halos. An important prediction of such a relaxation process is that spherical equilibrium states can be described by a Fermi-Dirac phase-space distribution, when the extremization of a coarse-grained entropy is reached. In the case of DM fermions, the most general solution develops a degenerate compact core surrounded by a diluted halo. As shown recently, the latter is able to explain the galaxy rotation curves while the DM core can mimic the central black hole. A yet open problem is whether this kind of astrophysical core-halo configurations can form at all, and if they remain stable within cosmological timescales. We assess these issues by performing a thermodynamic stability analysis in the microcanonical ensemble for solutions with given particle number at halo virialization in a cosmological framework. For the first time we demonstrate that the above core-halo DM profiles are stable (i.e. maxima of entropy) and extremely long lived. We find the existence of a critical point at the onset of instability of the core-halo solutions, where the fermion-core collapses towards a supermassive black hole. For particle masses in the keV range, the core-collapse can only occur for Mvir ≳ E9M⊙ starting at zvir ≈ 10 in the given cosmological framework. Our results prove that DM halos with a core-halo morphology are a very plausible outcome within nonlinear stages of structure formation.

scholarly journals AGN Spectra as Seen by the Infrared Space Observatory: First Results

1997 ◽  
Vol 159 ◽  
pp. 333-336
Author(s):  
D. Lutz ◽  
R. Genzel ◽  
E. Sturm ◽  
A.F.M. Moorwood ◽  
E. Oliva ◽  
...  
Keyword(s):  
Fine Structure ◽  
Short Wavelength ◽  
Molecular Hydrogen ◽  
Molecular Gas ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
First Results ◽  
External Galaxies ◽  
First Time ◽  
Fine Structure Lines

AbstractWe discuss 2.5–45 µm spectra of the Circinus galaxy and of Cen A, obtained with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory. The large number of detected ionic fine structure lines, observable also in visually obscured sources, provides strong constraints on the shape of the ionizing spectrum, which is found to exhibit a UV bump peaking at ~ 70 eV in the case of Circinus. Pure rotational emission of molecular hydrogen, directly probing warm molecular gas, can for the first time be detected in external galaxies.

Very high sensitivity optical modulators based on band filling effect in GaInAs quantum wells

1990 ◽  
Author(s):  
T.Y. Chang ◽  
J.E. Zucker ◽  
K.L. Jones ◽  
N.J. Sauer ◽  
B. Tell ◽  
...  
Keyword(s):  
Quantum Wells ◽  
High Sensitivity ◽  
Optical Modulators ◽  
Band Filling ◽  
Very High

scholarly journals Extended analysis of Xe VII and Xe VIII

2017 ◽  
Vol 95 (9) ◽  
pp. 805-810 ◽  
Author(s):  
M. Raineri ◽  
M. Gallardo ◽  
J. Reyna Almandos ◽  
C.J.B. Pagan ◽  
R. Sarmiento
Keyword(s):  
Light Source ◽  
Energy Levels ◽  
Excited Configuration ◽  
Pulsed Discharge ◽  
Hartree Fock ◽  
The Core ◽  
New Energy ◽  
Extended Analysis ◽  
First Time ◽  
Atomic Parameters

A pulsed discharge light source to study the six and seven times ionized xenon spectra in the 419–4642 Å region was used. A set of 40 transitions of Xe VII and 25 transitions of Xe VIII were classified for the first time. We revised the values for the previously known energy levels and extended the analysis for Xe VII to 10 new energy levels belonging to 5s6d, 5s7s and 5s7p, 4d95s25p even and odd configurations, respectively. Seven new energy levels of the core excited configuration 4d95s5d of Xe VIII are presented. For the prediction of the atomic parameters, energy levels, and transition, relativistic Hartree–Fock calculations were used.

scholarly journals Intra-Day Variability Observations of Two Dozens of Blazars at 4.8 GHz

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 15
Author(s):  
Xiang Liu ◽  
Xin Wang ◽  
Ning Chang ◽  
Jun Liu ◽  
Lang Cui ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Forthcoming Paper ◽  
Galactic Latitude ◽  
Local Interstellar Medium ◽  
Bl Lac Objects ◽  
Spectrum Radio ◽  
First Results ◽  
First Time ◽  
Source Structure

Two dozens of radio loud active galactic nuclei (AGNs) have been observed with Urumqi 25 m radio telescope in order to search for intra-day variability (IDV). The target sources are blazars (namely flat spectrum radio quasars and BL Lac objects) which are mostly selected from the observing list of RadioAstron AGN monitoring campaigns. The observations were carried out at 4.8 GHz in two sessions of 8–12 February 2014 and 7–9 March respectively. We report the data reduction and the first results of observations. The results show that the majority of the blazars exhibit IDV in 99.9% confidence level, some of them show quite strong IDV. We find the strong IDV of blazar 1357 + 769 for the first time. The IDV at centimeter-wavelength is believed to be predominately caused by the scintillation of blazar emission through the local interstellar medium in a few hundreds parsecs away from Sun. No significant correlation between the IDV strength and either redshift or Galactic latitude is found in our sample. The IDV timescale along with source structure and brightness temperature analysis will be presented in a forthcoming paper.

Sign in / Sign up

Export Citation Format

Share Document