Volume 2 Issue 4
Authors: A.S. Dikalyuk; S.T. Surzhikov
Abstract: The computational model of nonequilibrium radiation of shock-heated gases is presented in this paper. In the model the flow in the relaxation zone behind the shock front is considered. The hydrodynamic description of the relaxation zone is performed in the framework of Euler system of equations. In the model equations of chemical kinetics and vibrational relaxation are solved. Also the energy balance equation for the temperature of electron gas calculation is included in the model. For the determination of the population of excited states of molecules the approach that we refer to as “hybrid collisional-radiative” is used. The “just-overlapping” line model is used for the calculation of radiative characteristics of shock-heated gases. The model is validated against the results of measurements of radiation in shock tube experiments performed on X2 facility.
Keywords: Nonequilibrium Radiation; Shock-Heated Gas Mixtures; Chemical Kinetics; Vibrational Relaxation
Authors: Y. Ichiyanagi; A. Kurokawa; T. Yanoh; S. Yano; K. Onuma; T. Kondo; K. Miike; T. Miyasaka; M. Hachisu; K. Mori; H. Takeuchi
Abstract: Fe3-xZnxO4 (x=0.2, 0.4, 0.6, 0.8, 1) nanoparticle with average diameters of 12 nm was produced by our novel wet chemical method. The crystal structure and magnetic property of the obtained particle were investigated by X-ray diffraction and superconducting quantum interference device (SQUID) magnetometer. Direct current (DC) magnetization measurement showed that the coercive force Hc and saturation magnetization Ms decreased as the composite parameter x increased. This phenomenon suggests that Zn2+ ions located on tetrahedral A sites weaken the superexchange interaction between tetrahedral A and octahedral B sites. From the alternative current (AC) magnetic susceptibility, a sample with composition of x=0.4 is expected for heating by external field. Temperature increase depending on the magnetic field strength and frequency supported that samples with composition of x=0.2, 0.4 were appropriate for use as an agent in hyperthermia treatment.
Keywords: Ferrite; Nanoparticle; Hyperthermia; Magnetic Susceptibility
Authors: Manabu Gouko
Abstract: In this study, I applied an actor-critic learning method to a mobile robot which uses a state representation based on distances between probability distributions. This state representation is proposed in a previous work and is insensitive to environmental changes, i.e., sensor signals maintaining an identical state even under certain environmental changes. The method, which constitutes a reinforcement learning algorithm, can handle continuous states and action spaces. I performed a simulation and verified that the mobile robot can learn a wall-following task. Then, I confirmed that the learned robot can achieve the same task when its sensors are artificially changed.
Keywords: Reinforcement Learning; Actor-Critic Method; State Representation; Mobile Robot
Authors: Rémi Casagrande; Olivier Maurice
Abstract: The study consists of predicting the electromagnetic performance of a complete link including the shielded link with a pigtail, the external shielding and the connector. The modeling of the complete link is performed with the Kron’s method. A computation verification is done through a comparison with a transfer impedance measure of this link in a triaxal structure.
Keywords: Kron’s Method; Pigtail; Cable; Transfer Impedance
Authors: A.R. Abdullah; N.H.T.H. Ahmad; A.Z. Shameri; N.A Abidullah; M.H. Jopri; E.F. Shair
Abstract: Bilinear time-frequency distributions (TFDs) are developed to represent time-varying signal jointly in time frequency representation (TFR). The TFDs offer a good time and frequency resolution, are appropriate to analyze power quality signals that consist of magnitude variation and multiple frequencies. However, the TFD suffers from cross-terms interferences because of their bilinear structures. In this paper, smooth-windowed Wigner-Ville distribution (SWWVD) is used to analyze power quality signals. The power quality signals are swell, sag, interruption, harmonic, interharmonic and transient. To get an accurate TFR, the parameters of the separable kernel are estimated from the signal. A set of performance measures are defined and used to compare the TFR for various kernel parameters. The comparison shows the signals with different parameters require different kernel settings in order to get the optimal TFR.
Keywords: Time-frequency Analysis; Power Quality; Bilinear Transformation
Authors: Nathan Burford; Yumin Zhang
Abstract: Quasi-3D helix metamaterial is constructed from a multilayered 2D spiral structure with capacitive coupling between the adjacent layers. The sample is implemented with PCB, and a linearly polarized microwave source is used in the measurement. The polarization plane is rotated to the opposite directions with left- and right-handed samples. The rotation angle is consistent with theoretical prediction.
Keywords: Metamaterial; Chiral Structure; Polarization
Authors: G. Vallejo Ortega; J. I. Sánchez Rivera
Abstract: This paper presents the most important conclusions of the acoustic study made in the Auditorium of the Manuel de Falla Centre in Granada (Spain). This auditorium works. In the context of the concert rooms in Spain, its position is emblematic because it acts as a starting point in the modern conception of these halls. This paper is divided into two parts: was built by the architect José María García de Paredes in 1978 and reopened in 1987, making it one of his most important and beloved • Description of the project progress up to the final construction of the auditorium: preliminary references of musical rooms, first sketches and blueprints, the evolution of the construction project from the moment the architect comes in touch with the acoustical consultant Lothar Cremer, as well as the changes made in the room in its reopening are analyzed. • Presentation of the acoustic simulation results: sound rays trajectories from the source to the receivers are analyzed and the acoustic parameters that define its sound quality are evaluated using the CATT Acoustic software.
Keywords: Manuel de Falla Auditorium; García de Paredes; Lothar Cremer; Acoustic Modelling by Computer; Acoustic Parameters
Authors: Hui Yin; Shenghu Wu; Sichuan Li; Chunqiong Liu; Kai Shi
Abstract: We introduce a stress decay process into a continuous cellular automaton version of the Olami-Feder-Christensen model of earthquakes. The most important model parameter is the decay level of non-conservation during local stress redistribution. In particular, the Gutenberg-Richter and Omori laws for aftershocks sequences can be reproduced synchronously by this model simulation. The simple toppling mechanism of this modified model is sufficient to account for the clustering of real aftershocks. The self-organized criticality properties of the model are discussed. The high correspondence of the simulated results to observations supports the hypothesis that fault systems are in a state of self-organized criticality. At the same time, our work suggests that the occurrence of self-organized criticality depends, at least in part, on the decay dynamics of the non-conservation.
Keywords: Aftershock; Self-organized Criticality; Gutenberg-Richter Law; Omori Law; OFC Earthquake Model
Authors: George Jandieri; Zhuzhuna Diasamidze; Mzia Diasamidze
Abstract: Second order statistical moments of scattered ordinary and extraordinary waves in magnetized turbulent plasma are investigated analytically and numerically using the smooth perturbation method. Correlation functions of the phase fluctuations are obtained in the principle and perpendicular planes for arbitrary correlation functions of electron density fluctuations. New features of both the Double-humped effect and scintillation spectra are analysed for anisotropic Gaussian and power-law wavenumber spectra taking into account diffraction effects. The scintillation level is estimated for different anisotropy factors and the angle of inclination of prolate irregularities with respect to the external magnetic field. Scintillation minimums of a temporal spectrum are calculated for different thicknesses of a plasma slab taking into account the movement of rigid irregularities and diffraction effects for scattered ordinary and extraordinary waves in turbulent magnetized plasma.
Keywords: Statistical Moments; Extraordinary Wave; Fluctuations; Power Spectrum; Radio Wave
Authors: J. Chauca; R. Doria
Abstract: Considering that nature also has a systemic behaviour, there is still space for a whole physics to be derived from gauge symmetry. Therefore, by observing such nature systemic behaviour, a systemic symmetry is introduced. It originates the so-called whole gauge theory. It is a model based on the meaning that to a given Lorentz group representation should be associated with a field family. So, given the representation {□(1/2),□(1/2)}, it provides a dynamics with N-potential fields rotating under a same symmetry group. It develops a new possibility for gauge invariance to be explored which is to work as building maker of a group of fields. Thus, given that nature work as a group, one moves from the usual physics given by just one field G_μ to a physics where this field is inserted in a group 〖{G〗_μ^I}. New properties are developed. At this work, one studies on such new features which are the fields non-linearity, granular and collective, connectivity, global interactivity, directive and circumstance, gauge organization, complexity. Our framework for this investigation is the abelian fields set {G_μ^I}. By analyzing the corresponding gauge invariant Lagrangian these new properties are deducted. They are showing a new physicality for the quanta. They are consequence from the parts to be enfolded in the whole given by the Lorentz group representation.
Keywords: Whole Abelian Model; Non-linearity; Connectivity; Gauge Organization; Complexity