ChemInform Abstract: Theoretical Considerations on the Stability of Trioxo(η5-cyclopentadienyl) Compounds of the Transition-Metals Manganese, Technetium, and Rhenium

Alloys of nickel and arsenic containing up to 60% As by weight have been studied by means of room temperature and high temperature Debye-Scherrer diagrams. Three compounds have been identified: Ni5As2, Ni12−xAs8 (maucherite), and NiAs (niccolite). The first of these is homogeneous from Ni5As2 to Ni4.8A2 at room temperature, and to Ni4.6As2 above 250 °C., while the latter is homogeneous from NiAs to Ni0.95As. Contrary to expectations the stability region of the compound Ni12−xAs8 is very narrow, and occurs at Ni11As8 rather than at Ni3As2. Evidence is presented in support of Hansen's contention that this compound has an incongruent melting point. Alloys in the region corresponding to Ni4.6As2 undergo two transitions below 200 °C, one of which is martensitic and produces a metastable phase, while the other is believed to result in the formation of a new compound, as yet unidentified. The diffraction patterns are discussed in some detail.

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Vortex Stability in a Large-Scale Internal Wave Shear

Journal of Physical Oceanography ◽

10.1175/jpo-d-11-0137.1 ◽

2012 ◽

Vol 42 (10) ◽

pp. 1668-1683 ◽

Cited By ~ 6

Author(s):

Anne-Marie E. G. Brunner-Suzuki ◽

Miles A. Sundermeyer ◽

M.-Pascale Lelong

Keyword(s):

Internal Wave ◽

Large Scale ◽

Baroclinic Instability ◽

Initial Perturbation ◽

Energy Spectra ◽

Vortex Stability ◽

Background Wave ◽

The Stability ◽

Theoretical Considerations ◽

Compound Vortex

Abstract The effect of a large-scale internal wave on a multipolar compound vortex was simulated numerically using a 3D Boussinesq pseudospectral model. A suite of simulations tested the effect of a background internal wave of various strengths, including a simulation with only a vortex. Without the background wave, the vortex remained apparently stable for many hundreds of inertial periods but then split into two dipoles. With increasing background wave amplitude, and hence shear, dipole splitting occurred earlier and was less symmetric in space. Theoretical considerations suggest that the vortex alone undergoes a self-induced mixed barotropic–baroclinic instability. For a vortex plus background wave, kinetic energy spectra showed that the internal wave supplied energy for the dipole splitting. In this case, it was found that the presence of the wave hastened the time to instability by increasing the initial perturbation to the vortex. Results suggest that the stability and fate of submesoscale vortices in the ocean may be significantly modified by the presence of large-scale internal waves. This could in turn have a significant effect on the exchange of energy between the submesoscale and both larger and smaller scales.

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Frist-Principles Study of Hydrogen Atom Diffusion on Transition Metal Doped Mg(0001) Surface

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.873.101 ◽

2013 ◽

Vol 873 ◽

pp. 101-109 ◽

Cited By ~ 3

Author(s):

Zhi Wen Wang ◽

Xin Jun Guo ◽

Wei Yuan ◽

Zhi Yan Ding

Keyword(s):

Hydrogen Atom ◽

Transition Metals ◽

Density Functional ◽

Atom Diffusion ◽

Charge Density Difference ◽

The Density Functional Theory ◽

Diffusion Paths ◽

The Stability ◽

Metal Doped ◽

Diffusion Of Hydrogen

First-principles calculations within the density functional theory (DFT) have been carried out to study the interaction of hydrogen atom with transition metals (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) doped Mg (0001) surfaces. First we have calculated the stability of the transition metals atom on the Mg surface, On the basis of the energetic criteria, all the elements except Zn prefer to substitute one of the Mg atoms from the second layer, while Zn tend to substitute one of the Mg atoms from the first layer. In the second step, we have studied the interaction between hydrogen atom and the transition metals doped Mg (0001) surface.we have studied the interaction of a hydrogen atom with the transition metals doped Mg (0001) surface. The results show that for transition metals atoms doped Mg (0001) surface in the second layer, it not only enhances the chemisorption interaction between hydrogen atom and Mg surface, but also it benefits hydrogen atom diffusion in Mg bulk with relatively more diffusion paths. However, when the Mg surface doped by elements such as Sc, Ti, V, Cu and Zn, hydrogen atom chooses to bond with transition metals atom and block the diffusion of hydrogen atom into Mg bulk, while when the Mg surface doped by elements such as Cr, Mn, Fe, Co and Ni, hydrogen atom chooses to leave from transition metals atom thereby promoting the diffusion of hydrogen atom diffusion into Mg bulk. Charge density difference plots shows that electrons are transferred from electronic states of transition metals atom to the orbital of hydrogen atom which cause attractive interactions between hydrogen atom and transition metals atom and reduce the energy barrier of the hydrogen atom diffusion into Mg bulk. Our results show that useing transition metals (Cr, Mn, Fe, Co and Ni) as catalysts for the hydrogenation/dehydrogenation of Mg bulk samples and provide more diffusion paths of hydrogen atom, they are beneficial for the diffusion of hydrogen atom to Mg bulk and improve significantly the hydrogenation kinetics property of Mg surface.

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The Short-Term Reliability of Metaphors as an Assessment Method

Frontiers in Education ◽

10.3389/feduc.2021.678327 ◽

2021 ◽

Vol 6 ◽

Author(s):

Elisabeth Wegner ◽

Christian Burkhart ◽

Matthias Nückles

Keyword(s):

Assessment Method ◽

Educational Science ◽

Short Term ◽

Surface Approach ◽

Innovative Tool ◽

The Stability ◽

The Moment ◽

Theoretical Considerations

Metaphors are assumed to be a means of accessing implicit aspects of cognition. Metaphors, therefore, have been increasingly used in educational science as an innovative tool to examine a broad range of constructs. However, there are both empirical findings and theoretical considerations suggesting that metaphors are also by experiences that are salient just in the moment of production of the metaphor. Therefore, we examined in a sample of N = 95 students and professionals whether the metaphors of learning and the underlying conceptualization of learning that influence whether students adopt a deep or a surface approach in learning remained stable across 3 weeks. Results showed that although the sources on which the metaphors drew were subject to change, the underlying conceptualization of learning remained stable. However, there were no differences in the stability of metaphors in both groups. It be can concluded, therefore, that metaphors can be used as an indicator for underlying constructs such as the understanding of learning.

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Are the Hessdalen Lights a Reality, an Illusion, or a Mix of the Two ?

Journal of Scientific Exploration ◽

10.31275/20212171 ◽

2021 ◽

Vol 35 (3) ◽

pp. 590-622

Author(s):

Gianni Pascoli

Keyword(s):

Field Measurements ◽

Full Description ◽

High Time Resolution ◽

Full Understanding ◽

Traversable Wormholes ◽

Magnetic Field Measurements ◽

The Stability ◽

Atmospheric Phenomena ◽

Theoretical Considerations ◽

Recent Idea

The Hessdalen lights (HLs in the following) are luminous, floating, more or less spherical atmospheric phenomena, with a lifetime of a few seconds to sometimes several minutes. These phenomena are seen in the Hessdalen Valley in Norway for decades. Unfortunately a full understanding of these baffling events is still lacking in spite of solid working scientific projects intended to explain them. This paper tries to improve the situation. It raises the questions where the energy for the creation of the HLs comes from, and what was its nature : (geo) chemical, electric or still other ? We propose a new scenario for the Hessdalen lights. It exploits the recent idea of stable and traversable wormholes whose the potential existence is beginning to be recognized in physics. Even though appearing highly speculative, this hypothesis has not been so far explored elsewhere while it could supply a full description of the wholeness of the phenomenon. On the other side even if the probability that a HL could indeed be a wormhole is may be low, this question should not dismissed out of hand. These theoretical considerations could help to increase knowledge and understanding of both the HLs and the wormholes, drawing mutual enrichment. In other words HLs could betray the presence of hidden wormholes and we must not let slip through our fingers this possibility even if it is very tiny. In this framework we discuss of the stability, the energetics and the oversized dimension of the HLs. In physics the final arbiter is not the theory but the experiment. Thus some “simple” experiments are eventually suggested (high time resolution photometry and magnetic field measurements). Eventually, if the process described is real and after mastering it, there is a free and inexhaustible source of energy that would be derived, a tremendous breakthrough after which we could forget the controlled nuclear fusion. Regarding its structure, the paper is divided in four paragraphs 1, 2,3, 4 independent of each other. Illustrative pictures help to understand the text.

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Interoceptive Awareness Is Negatively Related to the Exteroceptive Manipulation of Bodily Self-Location

Frontiers in Psychology ◽

10.3389/fpsyg.2020.562016 ◽

2020 ◽

Vol 11 ◽

Author(s):

Robin Bekrater-Bodmann ◽

Ruben T. Azevedo ◽

Vivien Ainley ◽

Manos Tsakiris

Keyword(s):

Essential Feature ◽

Interoceptive Awareness ◽

Person Perspective ◽

Body Experiences ◽

Third Person ◽

Different Dimensions ◽

Third Person Perspective ◽

The Stability ◽

Interoceptive Accuracy ◽

Theoretical Considerations

The perception of being located within one’s body (i.e., bodily self-location) is an essential feature of everyday self-experience. However, by manipulating exteroceptive input, healthy participants can easily be induced to perceive themselves as being spatially dislocated from their physical bodies. It has previously been suggested that interoception, i.e., the processing of inner physiological signals, contributes to the stability of body representations; however, this relationship has not previously been tested for different dimensions of interoception and bodily self-location. In the present study, using an advanced automatized setup, we systematically manipulated participants’ perspective of their own body (first- vs third-person perspective) as well as the synchrony of visuotactile stimulation (synchronous vs asynchronous). The malleability of bodily self-location was assessed using a questionnaire targeting in-body and out-of-body experiences. Participants also performed a heartbeat discrimination task to assess their interoceptive accuracy (behavioral performance), interoceptive sensibility (confidence in their interoceptive abilities), and interoceptive awareness (meta-cognitive representation of interoceptive signals). Bodily self-location was significantly influenced by perspective, with third-person perspective being associated with stronger out-of-body experiences compared to first-person perspective. Furthermore, there was a significant perspective × stimulation interaction, with subsequent analyses showing that participants reported out-of-body experiences particularly under third-person perspective combined with synchronous visuotactile stimulation. Correlation and regression analyses revealed that meta-cognitive interoceptive awareness was specifically and negatively related to the exteroceptively mediated malleability of body experiences. These results indicate that the perception of the self being located within one’s body relies on the interaction of exteroceptive input and higher-order interoceptive abilities. This has implications for theoretical considerations about the bodily self in health as well as for the understanding of disturbed bodily self-processing in clinical contexts.

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