Specialized turbomolecular pumping stage for RF ion thrusters

This paper proposes the application of a highly specialized Turbomolecular Vacuum Pump (TMP) device as a subsystem for electrostatic RF ion thrusters, using D. Fearn’s Dual-Stage 4-Grid design as a cutting-edge example. The TMP turbine’s rotor impulse is transmitted via collisions to neutral gas atoms en route to their ionization, with the goal of producing an anisotropic ion flux that is directed at the extracting screen grid. Operating regimes of such thruster design are hypothesized, and electromagnetic complexities of realization of this concept are identified

John Dewey and the Mind-Body Problem in the Context: The Case of «Neutral Monism»

The main focus of this paper is the mind-body problem in its relation to the doctrine of ‘neutral monism’ and the question who can be considered its proponents. According to Bertrand Russell, these are Ernst Mach, William James, and John Dewey (to name a few). This paper aims to clarify whether Russell himself was right in his conclusions or not. At first, I start with the clarification of the relation between ‘neutral monism’ and ‘dual-aspect theory’. Secondly, I analyze the ‘big three’ of the neutral monism: Mach, James and Russell. My starting-point here is Russell’s very understanding of Mach and James positions. In the end, it appears that neither Mach, nor James as well as Dewey can be considered as neutral monists. It was rather Russell’s misunderstanding of the both James’ radical empiricism and Mach’s analysis of sensations, which led him to the creation of his own original version of ‘neutral monism’ (or ‘Russelian monism’)

Metal-insulator transition and local-moment collapse in FeO under pressure

We employ a combination of the \emph{ab initio} band structure methods and dynamical mean-field theory to determine the electronic structure and phase stability of paramagnetic FeO at high pressure and temperature. Our results reveal a high-spin to low-spin transition within the B1 crystal structure of FeO upon compression of the lattice volume above 73~GPa. The spin-state transition is accompanied by an orbital-selective Mott metal-insulator transition (MIT). The lattice volume is found to collapse by about 8.5~\% at the MIT, implying a complex interplay between electronic and lattice degrees of freedom. Our results for the electronic structure and lattice properties are in overall good agreement with experimental data.Comment: 6 pages, 5 figure

Facing Up to David Chalmers’ Philosophy of Mind: the General Overview

According to Tim Crane, “the ’hard problem’ of consciousness is supposed to be the real heart of the mind-body problem in today’s philosophy”. The idea of the problem can be expressed in the following way: Why are the physical processes in our brain accompanied by the qualitative (or phenomenal) feel? The mere qualitative feel or qualia are those to be explained. The originator of the problem’s name is the Australian philosopher David Chalmers who divided the problems of consciousness into the ‘easy’ problems and the ‘hard’ problem. The former are ‘easy’ because they can be functionally explained. The ‘hard’ problem, in its turn, cannot. From this, it follows that the explanation of the hard problem of consciousness must be found elsewhere. Chalmers’ nonreductive theory of consciousness (or naturalistic dualism) is a serious candidate for a such-like explanation. In general, it suggests conscious experience as one of the fundamental features of our world, together with such fundamental world features as mass, charge etc. It is a general overview of David Chalmers’ philosophy of mind that is carrying out in the proposed paper. Key words: the ‘easy’ problems and the ‘hard’ problem of consciousness, the phenomenal and psychological concepts of mind, awareness, experience, something it is like, qualia, supervenience, zombie, naturalistic dualism, the principle of structural coherence, the principle of organizational invariance, the double-aspect theory of information

Hilbert's 16th Problem for Quadratic Systems. New Methods Based on a Transformation to the Lienard Equation

Fractionally-quadratic transformations which reduce any two-dimensional quadratic system to the special Lienard equation are introduced. Existence criteria of cycles are obtained

Correlated electronic structure, orbital-dependent correlations, and Lifshitz transition in tetragonal FeS

Using density functional plus dynamical mean-field theory method (DFT+DMFT) with full self-consistency over the charge density, we study the effect of electronic correlations on the electronic structure, magnetic properties, orbital-dependent band renormalizations, and Fermi surface of the tetragonal phase of bulk FeS. We perform a direct structural optimization of the $P_4/nmm$ crystal structure of paramagnetic FeS, with respect to the lattice constant $a$ and the internal coordinate $z_\mathrm{S}$ of atom S. Our results show an anomalous sensitivity of the electronic structure and magnetic properties of FeS to fine details of its crystals structure. Upon expansion of the lattice volume, we observe a remarkable change of the electronic structure of FeS which is associated with a complete reconstruction of the Fermi surface topology (Lifshitz transition). This behavior is ascribed to a correlation-induced shift of the Van Hove singularity associated with the Fe $t_2$ orbitals at the $M$ point across the Fermi level. The Lifshitz phase transition is accompanied by a significant growth of local magnetic moments and emergence of strong orbital-selective correlations. It is seen as a pronounced anomaly (`kink') in the total energies upon expansion of the lattice, associated with a remarkable enhancement of compressibility. This behavior is accompanied by an orbital-dependent formation of local moments, a crossover from itinerant to localized orbital-selective moment behavior of the Fe $3d$ electrons. While exhibiting weak effective mass enhancement of the Fe $3d$ states $m^*/m \sim 1.3-1.4$, correlation effects reveal a strong impact on a position of the Van Hove singularity at the $M$ point, implying a complex interplay between electronic correlations and band structure effects in FeS