Phase diagram of the one dimensional anisotropic Kondo-necklace model

The one dimensional anisotropic Kondo-necklace model has been studied by several methods. It is shown that a mean field approach fails to gain the correct phase diagram for the Ising type anisotropy. We then applied the spin wave theory which is justified for the anisotropic case. We have derived the phase diagram between the antiferromagnetic long range order and the Kondo singlet phases. We have found that the exchange interaction (J) between the itinerant spins and local ones enhances the quantum fluctuations around the classical long range antiferromagnetic order and finally destroy the ordered phase at the critical value, J_c. Moreover, our results show that the onset of anisotropy in the XY term of the itinerant interactions develops the antiferromagnetic order for J<J_c. This is in agreement with the qualitative feature which we expect from the symmetry of the anisotropic XY interaction. We have justified our results by the numerical Lanczos method where the structure factor at the antiferromagnetic wave vector diverges as the size of system goes to infinity.Comment: 9 pages and 9 eps figure

Data-centric communication framework for multicast iec 61850 routable GOOSE messages over the WAN in modern power systems

In this paper, a data-centric communication framework is proposed for multicast routable generic object-oriented substation event (GOOSE) messages (MRGM) over the wide area network (WAN) for effective substation-to-substation (SS2SS) and substation to control center (SS2CC) communications. In this structure, the IEC 61850 GOOSE message is transmitted over the WAN using the data distribution service (DDS) as a fast, reliable, and secure data-centric communication middleware. The main feature of this framework is its multicast capability, where several authorized subscribers can receive a published message simultaneously. This can significantly improve the system monitoring and control of the protection systems in modern smart grids, where intelligent schemes can be applied. The effectiveness of the proposed platform, in terms of total end-to-end delay between participants, is evaluated through experimental results obtained from the actual hardware-based test setup developed at the Florida International University (FIU) smart grid testbed. The results demonstrate that the latency between sending and receiving a GOOSE message among participants is within its maximum time span defined by the IEC 61850-90-5 working group for communications over the WAN

A New Technique for Investigating Dust Charging in the PMSE Source Region

A new technique for investigating dust charging in the PMSE (polar mesospheric summer echoes) source region is proposed and discussed in this paper. The first high-frequency (HF) modulation of the PMSE with varying pump power was employed during a recent experimental campaign at EISCAT (European Incoherent Scatter Scientific Association). Two experiment setups including HF pump power stepping as well as quasi-continuous power sweeping were used. The experiment was designed based on a computational model capable of simulation of PMSE evolution during HF pump modulation in order to develop a new approach for studying the dust charging process in the PMSE source region. The charge state of dust particles along with background dusty plasma parameters is estimated using the experimental and computational results. A detailed future experimental design based on background dusty-plasma parameters is proposed. ©2020. American Geophysical Union. All Rights Reserved

Optimal power routing scheme between and within interlinking converters in unbalanced hybrid AC–DC microgrids

An optimal power routing (OPR) scheme between and within interlinking converters (ICs) in unbalanced hybrid AC–DC microgrids to minimise the power imbalance factor at the point of common coupling, active power losses, and voltage deviation indices for microgrids in grid-connected operating mode is proposed in this study. These goals are achieved through a multi-objective optimisation model by optimal distributing of mobile loads between available charging stations and at the same time, OPR within three phases of three-phase four-lag AC/DC converters. Numerical results obtained from implementing the proposed method on the modified IEEE 13-bus system, as an unbalanced hybrid microgrid, and IEEE 34-bus test system, as an unbalanced distribution system, demonstrate that proposed OPR algorithm is successful to satisfy the optimisation goals. For this purpose, four case studies are defined and studied to demonstrate the unique features of the proposed OPR comparing with other power routing schemes. In addition to simulation results, the OPR scheme between ICs is realistically implemented at Florida International University smart grid testbed to show the effect of the power routing on energy losses reduction

Aberrant Frequency Related Change-Detection Activity in Chronic Tinnitus

Tinnitus is the perception of sound without the occurrence of an acoustic event. The deficit in auditory sensory or echoic memory may be the cause of the perception of tinnitus. This study considered the mismatch negativity (MMN) to investigate the potential difference between and within groups of persons with normal hearing (NH) and tinnitus. Using an auditory multi-feature paradigm to elicit the MMN, this study considered the MMN peak amplitude at two central frequencies for two MMN subcomponents. These central frequencies were 1 and 5 kHz, which the latter was closer to the perceived tinnitus frequency in the group with tinnitus. The deviants were higher frequency, lower frequency, higher intensity, lower intensity, duration, location (left), location (right), and gap. The pure tone audiometry (PTA) test and distortion product otoacoustic emissions (DPOAE) test showed no meaningful difference between the two groups. For the frontal subcomponent, the mean amplitudes of the MMN peak for the two groups illustrated less negative meaningful MMN peak amplitudes in the group of persons with tinnitus. For the supratemporal component at 5 kHz central frequency, amplitudes were lower for the group of persons with tinnitus, whereas for the central frequency of 1 kHz, most deviants exhibited meaningful differences. Additionally, within-group comparisons indicated that mean amplitudes for both groups were more negative at the central frequency of 1 kHz for the frontal MMN subcomponent. In comparison, the supratemporal component illustrated a lower peak amplitude at 5 kHz central frequency in the group of persons with tinnitus and no difference in the NH group, which is a unique observation of this study. Results of the between-groups are in accordance with previous studies and within-group comparisons consider the probability of decreasing the change detection capability of the brain. The results of this study indicate that increasing the frequency of the stimuli close to the tinnitus perceived frequencies decreases the prediction error, including the prediction error of the silence. Such a decrease may cause the prediction error of the spontaneous neural activity in the auditory pathway to exceed the silence prediction error, and as a result, increases the probability of occurrence of tinnitus in higher frequencies according to the predictive coding model. © Copyright © 2020 Asadpour, Jahed and Mahmoudian

Investigation of incoherent scatter radar spectra features with stimulated electromagnetic emissions at EISCAT

Electromagnetic (EM) and electrostatic (ES) emissions can be generated in the ionosphere by high-power high-frequency (HF) radio waves transmitted from the ground. The signatures of the EM emissions observed on the ground are known as Stimulated Electromagnetic Emissions (SEE) and can be employed for remote measurement of ionospheric parameters. The experimental data from recent HF heating experiments near the fourth electron gyro-frequency (4f ce ) at EISCAT are presented. This paper compares the temporal behavior of SEE within a few Hertz up to 50 kHz of the transmission frequency to the time evolution of enhanced ion line (EHIL) in the incoherent scatter radar (ISR) spectrum. The correlation of Wideband SEE (WSEE) spectral lines within 1 kHz to 100 kHz such as the downshifted maximum (DM), downshifted peak (DP), and broad upshifted maximum (BUM), with HF enhanced ion lines (EHIL) is shown. It is shown that WSEE spectral lines can be used to reproduce the EHIL characteristics including altitude range, rise and decay time, maximum and minimum amplitude. A data reduction technique is developed to derive ionospheric parameters such as the electron density profile near the interaction altitude, magnetic field strength B 0 as well as the altitude profile of the EHIL using the temporal evolution of WSEE spectral lines near nf ce . © 2019 COSPA

An optimal energy management system for real-time operation of multiagent-based microgrids using a T-cell algorithm

The real-time operation of the energy management system (RT-EMS) is one of the vital functions of Microgrids (MG). In this context, the reliability and smooth operation should be maintained in real time regardless of load and generation variations and without losing the optimum operation cost. This paper presents a design and implementation of a RT-EMS based on Multiagent system (MAS) and the fast converging T-Cell algorithm to minimize the MG operational cost and maximize the real-time response in grid-connected MG. The RT-EMS has the main function to ensure the energy dispatch between the distributed generation (DG) units that consist in this work on a wind generator, solar energy, energy storage units, controllable loads and the main grid. A modular multi-agent platform is proposed to implement the RT-EMS. The MAS has features such as peer-to-peer communication capability, a fault-tolerance structure, and high flexibility, which make it convenient for MG context. Each component of the MG has its own managing agent. While, the MG optimizer (MGO) is the agent responsible for running the optimization and ensuring the seamless operation of the MG in real time, the MG supervisor (MGS) is the agent that intercepts sudden high load variations and computes the new optimum operating point. In addition, the proposed RT-EMS develops an integration of the MAS platform with the Data Distribution Service (DDS) as a middleware to communicate with the physical units. In this work, the proposed algorithm minimizes the cost function of the MG as well as maximizes the use of renewable energy generation; Then, it assigns the power reference to each DG of the MG. The total time delay of the optimization and the communication between the EMS components were reduced. To verify the performance of our proposed system, an experimental validation in a MG testbed were conducted. Results show the reliability and the effectiveness of the proposed multiagent based RT-EMS. Various scenarios were tested such as normal operation as well as sudden load variation. The optimum values were obtained faster in terms of computation time as compared to existing techniques. The latency from the proposed system was 43% faster than other heuristic or deterministic methods in the literature. This significant improvement makes this proposed system more competitive for RT applications

Rapid and efficient ultrasonic assisted adsorption of diethyl phthalate onto FeIIFe2 IIIO4@GO: ANN-GA and RSM-DF modeling, isotherm, kinetic and mechanism study

Herein, an ultrasonic assisted dispersive magnetic solid-phase adsorption method along with a high-performance liquid chromatography system for the diethyl phthalate (DEP) removal was developed. In this regard, magnetic iron oxide/graphene oxide (MGO) nanocomposites were prepared by a simple and effective chemical co-precipitation method, followed by nucleation and growth of nanoparticles. The structure and morphology of MGO was identified by Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX) spectroscopy X-ray diffraction (XRD), Vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and N2 adsorption-desorption techniques. The interactive and main effect of parameters such as pH, adsorbent dosage, sonication time and concentration of DEP involved in the adsorption process were set within the ranges 3.0�11.0, 0.10�0.50 g L�1, 1�5 min, 5�10 mg/L, respectively. Root means square error (RMSE), mean absolute error (MAE), absolute average deviation (AAD), and coefficient of determination (R2) was employed to examine the applicability of the response surface methodology (RSM) and artificial neural network (ANN) models for the description of experimental data. Compared to RSM, the ANN showed a more accurate performance for modeling the process of DEP adsorption. Using genetic algorithm-ANN, optimum conditions were set to 5.38, 334.7 mg/L, 3.723 min and 4.21 mg/L for pH, adsorbent dose, sonication time and concentration of DEP, respectively. Under the optimized conditions, the maximum adsorption capacity and adsorption factors were 116.933 mg/g and 100, respectively, while the relative standard deviations (RSDs) was &lt;1.6 (N = 5). The isotherm models display that the Langmuir has the best fit with the equilibrium data, and adsorption kinetics followed the pseudo-second-order model. The thermodynamic results confirmed that the sorption was endothermic and occurred spontaneously. The results exhibited that MGO has excellent potential as an adsorbent for the removal of phthalates from the contaminated water. © 2019 Elsevier B.V

Stabilization and Anticancer Enhancing Activity of the Peptide Nisin by Cyclodextrin-Based Nanosponges against Colon and Breast Cancer Cells

The great variability of cancer types demands novel drugs with broad spectrum, this is the case of Nisin, a polycyclic antibacterial peptide that recently has been considered for prevention of cancer cells growth. As an accepted food additive, this drug would be very useful for intestinal cancers, but the peptide nature would make easier its degradation by digestion procedures. For that reason, the aim of present study to investigate the protective effect of two different β-cyclodextrin-based nanosponges (carbonyl diimidazole and pyromellitic dianhydride) and their anti-cancer enhancement effect of Nisin-Z encapsulated with against colon cancer cells (HT-29). To extend its possible use, a comparison with breast (MCF-7) cancer cell was carried out. The physicochemical properties, loading efficiency, and release kinetics of Nisin complex with nanosponges were studied. Then, tricin-SDS-PAGE electrophoresis was used to understand the effect of NSs on stability of Nisin-Z in the presence of gastric peptidase pepsin. In addition, the cytotoxicity and cell membrane damage of Nisin Z were evaluated by using the MTT and LDH assay, which was complemented via Annexin-V/ Propidium Iodide (PI) by using flowcytometry. CD-NS are able to complex Nisin-Z with an encapsulation efficiency around 90%. A protective effect of Nisin-Z complexed with CD-NSs was observed in presence of pepsin. An increase in the percentage of apoptotic cells was observed when the cancer cells were exposed to Nisin Z complexed with nanosponges. Interestingly, Nisin Z free and loaded on PMDA/CDI-NSs is more selectively toxic towards HT-29 cells than MCF-7 cancer cells. These results indicated that nanosponges might be good candidates to protect peptides and deliver drugs against intestinal cancers