Flux Dynamics in Tl2Ba2CaCu2O8 Thin Films

Investigations on flux dynamics of ring-shaped T1₂Ba₂CaCu₂O₈ superconducting thin films have been carried out by measuring the temperature dependent magnetization M(T) during field-cooling (FC) and zero-field-cooling (ZFC) processes. For a given magnetic field, from the magnetization behavior two distinct temperatures, T_kink and T_irr, can be defined. Below T_kink, a clear hysteretic behavior of M(T) is observed leading to a large irreversible signal ΔM = M_FC ? M_ZFC. Above T_kink, this irreversible signal, though being very small, is still non-zero until it eventually vanishes at a higher temperature T_irr. Above T_irr, both curves M_FC(T) and M_ZFC(T) merge together and become temperature independent. We attribute the first region ( T< T_kink) to a 3D vortex-glass phase, the second region (T_kink < T < T_irr) to a vortex line liquid state and the third region (T_irr < T < T_c) to a pancake liquid state.     

Voltage phasor and local system frequency estimation using Newtontype algorithm

A new approach to the design of a digital algorithm for voltage phasor and local system frequency estimation is presented. The estimation problem is considered as an unconstrained optimization problem. The algorithm is derived using Newton's iterative method, very commonly used in load-flow studies. The algorithm showed a very high level of robustness as well as high measurement accuracy over a wide range of frequency changes. The algorithm convergence of order two provided fast response and adaptability. To demonstrate the performance of the algorithm developed, computer simulated, experimentally obtained and real-life data records are processed. The presented work is a part of a project concerning the application of microprocessors in frequency relaying     

Energy Dissipation Control in Hydro-Abrasive Machining Using Quantitative Acoustic Emission

The efficiency and product quality of hydro-abrasive machining (HAM) could be considerably improved if the energy dissipation phenomenon of the jet-like tool during the material removal is clearly understood. An on-line technique for quantifying the amount of energy dissipated in the workpiece during HAM using acoustic emission (AE) measurements is presented in this paper. The measured AE-signals are linked to a physical energy dissipation model. Stochastic modelling of the AE-signals provides more information on the physics of the energy dissipation process.     

An architecture for the vlsi design of systems for time-frequency analysis and time-varying filtering

A flexible system for time-frequency signal analysis is presented. It is based on the S-method, which has a significant advantage in implementation since it can involve, as a key intermediate step, the Short-time Fourier transform or the Hartley transform, each widely studied and commonly used in practice. Signal invariant and signal dependent system forms are presented. Hardware design, for a fixed-point arithmetic, is well-structured and suitable for vlsi implementation. The same hardware, without additional time requirements, may be shared for the simultaneous realization of the fourth order L-Wigner distribution, as well as for the realization of the cross-terms free fourth order polynomial Wigner-Ville distribution. This possibility makes the designed hardware suitable for wide range of the applications. The proposed hardware is applied to the realization of time-varying filtering, as well. Finally, it has been implemented with fpga chips (Field Programmable Gate Array) in order to verify the results on real devices.     

Local echo canceler with optimal input for true full-duplex speechscrambling system

The purpose of this paper is to focus on the local echo-canceling problem of full-duplex scrambled speech communications over a two-wire telephone network when the scrambling transformation is located between the handset and body of a telephone. Such a design makes possible very efficient protection against electromagnetic compromising emanation, which in turn substantially enhances the overall security of a protected communication. We propose a new adaptive FIR filter algorithm for local echo cancellation in such applications. The proposed algorithm differs from the conventional one by the construction of input signals in an optimal way using the D-optimal experiment design. In this way, at each step, we generate a new sample of the D-optimal pilot sequence for the filter parameter estimation. Consequently, the adaptation of the local echo canceler is defined as an initialization process in the first phase of each protected telephone call. The advantage in using the proposed adaptive FIR echo canceler is demonstrated through simulation results     

On-line monitoring of depth of cut in AWJ cutting

Monitoring of the abrasive waterjet (AWJ) cutting process has become increasingly important. The present paper proposes a model for on-line depth of cut monitoring based on the acoustic emission (AE) response to the variation in AWJ depth of cut, instead of the expensive and impractical vertical cutting force monitoring. The main objective is to use the AE technique in order to predict the actual depth of cut in AWJ cutting under normal cutting conditions. It was found that the root mean square of the acoustic emission energy (AErms) increases linearly with an increase in the depth of cut and could be used for its on-line monitoring. The results show that the AE is the most suitable technique for AWJ monitoring, as the AE signal has high sensitivity to the variation in the depth of cut.     

Implications of Tc-Variation in UBe13 for a Possible Fulde–Ferrell–Larkin–Ovchinnikov Phase

We measure the heat capacity of a UBe₁₃ sample with an unusually low T _c for a polycrystal. We find an upturn in the upper critical field H _c2(T) below about T _c/2, much as for higher-T _c samples. Comparing the critical fields in our sample and in samples with higher T _c's shows that the low temperature limit of H _c2 is proportional to T _c(H = 0), as expected if the upturn comes from an FFLO phase and strong coupling.     

Inhibiting Islet Amyloid Polypeptide Fibril Formation by the Red Wine Compound Resveratrol

Grapes for amyloids : The red wine compound resveratrol can effectively inhibit the formation of IAPP amyloid that is found in type II diabetes. Our in vitro inhibition results do not depend on the antioxidant activity of resveratrol. Further, the markedly enhanced cell survival in the presence of resveratrol also indicates that the small oligomeric structures that are observed during β‐sheet formation are not toxic and could be off‐pathway assembly products.

     

Greenhouse gas emissions from thermal treatment of non-recyclable municipal waste

This paper analyses factors affecting the production of greenhouse gases from the treatment of residual municipal waste. The analysis is conducted so that the environmentally-friendly decision-making criteria may be later implemented into an optimisation task, which allocates waste treatment capacities. A simplified method of life cycle assessment is applied to describe environmental impact of the allocation. Global warming potential (GWP) is employed as a unit to quantify greenhouse gases (GHG) emissions. The objective is to identify the environmental burdens and credits measured by GWP for the three fundamental methods for treatment of residual waste unsuitable for material recovery. The three methods are waste-to-energy (WTE), landfilling and mechanicalbiological treatment (MBT) with subsequent utilization of refuse-derived fuel. The composition of the waste itself and content of fossil-derived carbon and biogenic carbon are important parameters to identify amounts of GHG. In case of WTE, subsequent use of the energy, e.g., in district heating systems in case of heat, is another important parameter to be considered. GWP function dependant on WTE capacity is introduced. The conclusion of this paper provides an assessment of the potential benefits of the results in optimisation tasks for the planning of overall strategy in waste management.

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