Tamper Proof RFID Security Tag

In this publication we present a tamper proof long range platform tolerant uhf smart RFID tag to identify valuable or security sensitive products. The smart tag functions as platform tolerant tag but once detached from the host object, it will permanently stop to function buy rendering the RFID chip unusable. The tag substrate design for additive manufacturing, platform tolerant antenna design as well as electromagnetic performance and read range are provided

Passive UHF RFID Tilt Sensor

In this paper we introduce a bio-axis passive wireless UHF RFID tilt sensor for applications such as to increase safety in warehouse environment and damage detection in consumer goods and where long term monitoring of the product is essential without the need to supply power to the sensors. Simulation and prototype testing indicate it is possible to detect and isolate tilting in 3 axes

Influence of substrate types and reflector proximities over a NDTC antenna

The influence of dissimilar substrates and reflector proximities over a newly developed Non-uniformly Distributed-Turns Coil (NDTC) antenna for High-Frequency (HF) Radio Frequency IDentification (RFID) applications is presented. In the study, the performance of the HF-RFID NDTC antenna over various substrates with deposited conductor thicknesses is conducted. In addition, the effect over a conceivably encountered reflector in the proximity of the antenna is considered. Insensitive reflection coefficient (S11) responses for different substrate permittivities were experienced and the diverse conductor types and thicknesses contributed to a compromised magnetic-field (H-field) and recalculated matching network. The matching network additionally preserves resonance when the antennas is in close proximity to the reflector and a predictable H-field response for the separation range is shown

Universality class of quantum criticality for strongly repulsive spin-1 bosons with antiferromagnetic spin-exchange interaction

Using the thermodynamic Bethe ansatz equations we study the quantum phase diagram, thermodynamics and criticality of one-dimensional spin-1 bosons with strongly repulsive density-density and antiferromagnetic spin-exchange interactions. We analytically derive a high precision equation of state from which the Tomonaga-Luttinger liquid physics and quantum critical behavior of the system are computed. We obtain explicit forms for the scaling functions near the critical points yielding the dynamical exponent $z=2$ and correlation length exponent $\nu=1/2$ for the quantum phase transitions driven by either the chemical potential or the magnetic field. Consequently, we further demonstrate that quantum criticality of the system can be mapped out from the finite temperature density and magnetization profiles of the 1D trapped gas. Our results provide the physical origin of quantum criticality in a 1D many-body system beyond the Tomonaga-Luttinger liquid description.Comment: 12 pages, 11 figure

Electromagnetic Coupling through Arbitrary Apertures in Parallel Conducting Planes

We propose a numerical methodto solve the problem of coupling through finite, but otherwise arbitrary apertures in perfectly conducting and vanishingly thin parallel planes. The problem is given a generic formulation using the Method of Moments and the Green's function in the region between the two planes is evaluated using Ewald's method. Numerical applications using Glisson's basis functions to solve the problem are demonstrated and compared with previously published results and the output of FDTD software

Exactly solvable models and ultracold Fermi gases

Exactly solvable models of ultracold Fermi gases are reviewed via their thermodynamic Bethe Ansatz solution. Analytical and numerical results are obtained for the thermodynamics and ground state properties of two- and three-component one-dimensional attractive fermions with population imbalance. New results for the universal finite temperature corrections are given for the two-component model. For the three-component model, numerical solution of the dressed energy equations confirm that the analytical expressions for the critical fields and the resulting phase diagrams at zero temperature are highly accurate in the strong coupling regime. The results provide a precise description of the quantum phases and universal thermodynamics which are applicable to experiments with cold fermionic atoms confined to one-dimensional tubes.Comment: based on an invited talk at Statphys24, Cairns (Australia) 2010. 16 pages, 6 figure

Shear dispersion along circular pipes is affected by bends, but the torsion of the pipe is negligible

The flow of a viscous fluid along a curving pipe of fixed radius is driven by a pressure gradient. For a generally curving pipe it is the fluid flux which is constant along the pipe and so I correct fluid flow solutions of Dean (1928) and Topakoglu (1967) which assume constant pressure gradient. When the pipe is straight, the fluid adopts the parabolic velocity profile of Poiseuille flow; the spread of any contaminant along the pipe is then described by the shear dispersion model of Taylor (1954) and its refinements by Mercer, Watt et al (1994,1996). However, two conflicting effects occur in a generally curving pipe: viscosity skews the velocity profile which enhances the shear dispersion; whereas in faster flow centrifugal effects establish secondary flows that reduce the shear dispersion. The two opposing effects cancel at a Reynolds number of about 15. Interestingly, the torsion of the pipe seems to have very little effect upon the flow or the dispersion, the curvature is by far the dominant influence. Lastly, curvature and torsion in the fluid flow significantly enhance the upstream tails of concentration profiles in qualitative agreement with observations of dispersion in river flow

Smart radio-frequency identification tag for diaper moisture detection

A passive smart tag is described that responds to dampness in diapers once a pre-defined threshold value is reached. A high-frequency (HF) system at 13.56 MHz is used as this allows operation through water or human tissues with less absorption that would occur for an ultra-HF signal. A circular spiral coil and swelling substrate facilitate a reaction to dampness that can be detected without contact to the diaper wearer. A prototype design is simulated and measured results are provided together with a demonstration of a tag integrated into a worn diaper

Phase diagram of the su(8) quantum spin tube

We calculate the phase diagram of an integrable anisotropic 3-leg quantum spin tube connected to the su(8) algebra. We find several quantum phase transitions for antiferromagnetic rung couplings. Their locations are calculated exactly from the Bethe Ansatz solution and we discuss the nature of each of the different phases.Comment: 10 pages, RevTeX, 1 postscript figur

Energetics and dynamics of simple impulsive solar flares

Flare energetics and dynamics were studied using observations of simple impulsive spike bursts. A large, homogeneous set of events was selected to enable the most definite tests possible of competing flare models, in the absence of spatially resolved observations. The emission mechanisms and specific flare models that were considered in this investigation are described, and the derivations of the parameters that were tested are presented. Results of the correlation analysis between soft and hard X-ray energetics are also presented. The ion conduction front model and tests of that model with the well-observed spike bursts are described. Finally, conclusions drawn from this investigation and suggestions for future studies are discussed