Biquadratic Filter Applications Using a Fully-Differential Active-Only Integrator

A new class of active filters, real active-only filters is described and possible implementation issues of these filters are discussed. To remedy these issues, a fully-differential active-only integrator block built around current controlled current conveyors is presented. The integration frequency of the proposed circuit is adjustable over a wide frequency range. As an application, a real active-only filter based on the classical two-integrator loop topology is presented and designed. The feasibility of this filter in a 0.35µm CMOS process is verified through SPECTRE simulation program in the CADENCE design tool

Invariance quantum group of the fermionic oscillator

The fermionic oscillator defined by the algebraic relations cc^*+c^*c=1 and c^{2}=0 admits the homogeneous group O(2) as its invariance group. We show that, the structure of the inhomogeneous invariance group of this oscillator is a quantum group.Comment: 7 A4 page

Quantum Group Covariance and the Braided Structure of Deformed Oscillators

The connection between braided Hopf algebra structure and the quantum group covariance of deformed oscillators is constructed explicitly. In this context we provide deformations of the Hopf algebra of functions on SU(1,1). Quantum subgroups and their representations are also discussed.Comment: 12 pages, to be published in JM

Modelling the components of binaries in Hyades: The dependence of the mixing-length parameter on stellar mass

We present our findings based on a detailed analysis for the binaries of the Hyades, in which the masses of the components are well known. We fit the models of components of a binary system to the observations so as to give the observed total V and B-V of that system and the observed slope of the main-sequence in the corresponding parts. According to our findings, there is a very definite relationship between the mixing-length parameter and the stellar mass. The fitting formula for this relationship can be given as $alpha = 9.19 (M/M_sun-0.74)^{0.053}-6.65$, which is valid for stellar masses greater than 0.77 M_sun. While no strict information is gathered for the chemical composition of the cluster, as a result of degeneracy in the colour-magnitude diagram, by adopting Z=0.033 and using models for the components of 70 Tau and theta^2 Tau we find the hydrogen abundance to be X=0.676 and the age to be 670 Myr. If we assume that Z=0.024, then X=0.718 and the age is 720 Myr. Our findings concerning the mixing length parameter are valid for both sets of the solution. For both components of the active binary system V818 Tau, the differences between radii of the models with Z=0.024 and the observed radii are only about 4 percent. More generally, the effective temperatures of the models of low mass stars in the binary systems studied are in good agreement with those determined by spectroscopic methods.Comment: 11 pages, 7 figures, accepted for publication in MNRA

Evanescent incompressible strips as origin of the observed Hall resistance overshoot

In this work we provide a systematic explanation to the unusual non-monotonic behavior of the Hall resistance observed at two-dimensional electron systems. We use a semi-analytical model based on the interaction theory of the integer quantized Hall effect to investigate the existence of the anomalous, \emph{i.e} overshoot, Hall resistance $R_{H}$. The observation of the overshoot resistance at low magnetic field edge of the plateaus is elucidated by means of overlapping evanescent incompressible strips, formed due to strong magnetic fields and interactions. Utilizing a self-consistent numerical scheme we also show that, if the magnetic field is decreased the $R_{H}$ decreases to its expected value. The effects of the sample width, temperature, disorder strength and magnetic field on the overshoot peaks are investigated in detail. Based on our findings, we predict a controllable procedure to manipulate the maxima of the peaks, which can be tested experimentally. Our model does not depend on specific and intrinsic properties of the material, provided that a single particle gap exists.Comment: A theoretical follow-up paper of arXiv:1007.258

Numerical Analysis of 1/28 Scaled HTGR Reactor Building Test Facility Response to Depressurization Event

Depressurized Loss of Forced Cooling (DLOFC) accident is an important type of accident scenario in High Temperature Gas-Cooled Reactor (HTGR) design which is initiated by a break in Helium Pressure Boundary (HPB). This class of accident scenarios results in a depressurization of primary helium coolant system with subsequent release of helium into the Reactor Building (RB) and to the atmosphere through Vented Low Pressure Containment (VLPC). After the total depressurization of helium depending on the specific accident scenarios, it is also possible that air enters into the Reactor Pressure Vessel (RPV) through the RB which can potentially react with fuel and the reactor internal components such as nuclear-grade graphite. In this study, GOTHIC model of a 1/28-scaled simplified test facility was developed to analyze the depressurization scenarios and validate them against the experimental data. Simulations were conducted in three phases by following the experiment sequence. In the first phase, natural leakage from the RB was modeled with two different methods to prepare the model for further analysis. In the second phase, post-depressurization refill of air into the RB compartments was analyzed and results were validated against experimental data. In third phase, two hypothetical depressurization scenarios were analyzed and results were compared with experimental data. Simulation results were found to be consistent with experimental data

Foraging swarms as Nash equilibria of dynamic games

Cataloged from PDF version of article.The question of whether foraging swarms can form as a result of a noncooperative game played by individuals is shown here to have an affirmative answer. A dynamic game played by N agents in 1-D motion is introduced and models, for instance, a foraging ant colony. Each agent controls its velocity to minimize its total work done in a finite time interval. The game is shown to have a unique Nash equilibrium under two different foraging location specifications, and both equilibria display many features of a foraging swarm behavior observed in biological swarms. Explicit expressions are derived for pairwise distances between individuals of the swarm, swarm size, and swarm center location during foraging. © 2013 IEEE