Further Comment on 'Encoding many channels on the same frequency through radio vorticity: first experimental test'

We show that the reply by Tamburini et al (2012 New J. Phys. 14 118002) to our previous comment (2012 New J. Phys. 14 118001) on the experiment reported in (2012 New J. Phys. 14 033001) actually does not invalidate any of the issues raised in our initial comment.Comment: 3 pages, 1 figur

Characteristic Functions Describing the Power Absorption Response of Periodic Structures to Partially Coherent Fields

Many new types of sensing or imaging surfaces are based on periodic thin films. It is explained how the response of those surfaces to partially coherent fields can be fully characterized by a set of functions in the wavenumber spectrum domain. The theory is developed here for the case of 2D absorbers with TE illumination and arbitrary material properties in the plane of the problem, except for the resistivity which is assumed isotropic. Sum and difference coordinates in both spatial and spectral domains are conveniently used to represent the characteristic functions, which are specialized here to the case of periodic structures. Those functions can be either computed or obtained experimentally. Simulations rely on solvers based on periodic-boundary conditions, while experiments correspond to Energy Absorption Interferometry (EAI), already described in the literature. We derive rules for the convergence of the representation versus the number of characteristic functions used, as well as for the sampling to be considered in EAI experiments. Numerical examples are given for the case of absorbing strips printed on a semi-infinite substrate.Comment: Submitted to JOSA

Statistics of the MLE and Approximate Upper and Lower Bounds - Part 1: Application to TOA Estimation

In nonlinear deterministic parameter estimation, the maximum likelihood estimator (MLE) is unable to attain the Cramer-Rao lower bound at low and medium signal-to-noise ratios (SNR) due the threshold and ambiguity phenomena. In order to evaluate the achieved mean-squared-error (MSE) at those SNR levels, we propose new MSE approximations (MSEA) and an approximate upper bound by using the method of interval estimation (MIE). The mean and the distribution of the MLE are approximated as well. The MIE consists in splitting the a priori domain of the unknown parameter into intervals and computing the statistics of the estimator in each interval. Also, we derive an approximate lower bound (ALB) based on the Taylor series expansion of noise and an ALB family by employing the binary detection principle. The accurateness of the proposed MSEAs and the tightness of the derived approximate bounds are validated by considering the example of time-of-arrival estimation

Evaluation of parasite antigens in Elisa for the detection of toxoplasma infection in pigs

One-third of the human world population is infected with the protozoan parasite Toxoplasma gondii Toxoplasmosis is an old disease but is still very underreported and neglected disease

Characterization of Power Absorption Response of Periodic 3D Structures to Partially Coherent Fields

In many applications of absorbing structures it is important to understand their spatial response to incident fields, for example in thermal solar panels, bolometric imaging and controlling radiative heat transfer. In practice, the illuminating field often originates from thermal sources and is only spatially partially coherent when reaching the absorbing device. In this paper, we present a method to fully characterize the way a structure can absorb such partially coherent fields. The method is presented for any 3D material and accounts for the partial coherence and partial polarization of the incident light. This characterization can be achieved numerically using simulation results or experimentally using the Energy Absorption Interferometry (EAI) that has been described previously in the literature. The absorbing structure is characterized through a set of absorbing functions, onto which any partially coherent field can be projected. This set is compact for any structure of finite extent and the absorbing function discrete for periodic structures

Early-age thermo-mechanical behaviour of concrete Supercontainers for radwaste disposal

The Belgian concept for the disposal of vitrified high-level waste and spent fuel assemblies is founded on the use of cylindrical concrete Supercontainers. This concept is based on a multiple barrier system where every component has its own specific safety function requirements. It consists of encapsulating the heat-emitting waste in a watertight carbon steel overpack and surrounding it by a cylindrical concrete buffer that will then be disposed in a deep clay layer. Finally, the buffer is sealed with a concrete lid. Th concrete materials provide favourable chemical conditions for the overpack allowing it to confine the radionuclides during the thermal phase. In addition, they also ensure shielding protection during construction and transport. A self-compacting concrete (SCC) and a Traditional Vibrated Concrete (TVC) are bein considered for the choice of the cementious buffer, enclosing the radwaste. The use of SCC will ease considerably the precast process and complies with all other requirements regarding strength, durability, chemical interactions,... A laboratory characterization program, in order to obtain the mechanical and thermal properties of the SCC, and 2.5 D thermal and crack modelling simulations, has been conducted to predict the early-age thermo-mechanical behaviour of the concrete buffer during the different construction stages, i.e. the casing of the buffer, insertion of the high-level waste and closure of the Supercontainer. Also the effect of gamma radiation and elevated temperatures on hardening SCC based mortar and hardened SCC was investigated. Finally, the prediction of the avoidance of through-going cracks in the concrete buffer is ensured by means of simulations, after implementation of the obtained test results, and by means of large scale tests, with temperature measurements, displacement and deformation registrations, for the validation of the simulation results of the early-age behaviour of the Supercontainer

A beamforming approach to the self-calibration of phased arrays

In this paper, we propose a beamforming method for the calibration of the direction-independent gain of the analog chains of aperture arrays. The gain estimates are obtained by cross-correlating the output voltage of each antenna with a voltage beamformed using the other antennas of the array. When the beamforming weights are equal to the average cross-correlated power, a relation is drawn with the StEFCal algorithm. An example illustrates this approach for few point sources and a 256-element array

Early age behaviour of concrete supercontainers for radioactive waste disposal

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