We experimentally investigate the dynamics of spin solitary waves (magnetic solitons) in a harmonically trapped, binary superfluid mixture. We measure the in situ density of each pseudospin component ...and their relative local phase via an interferometric technique we developed and as such, fully characterize the magnetic solitons while they undergo oscillatory motion in the trap. Magnetic solitons exhibit nondispersive, dissipationless longtime dynamics. By imprinting multiple magnetic solitons in our ultracold gas sample, we engineer binary collisions between solitons of either the same or opposite magnetization and map out their trajectories.
A CFD study is conducted in order to characterize the dynamic behavior of a Savonius vertical axis wind turbine. All simulations are executed using the open source code, OpenFOAM. Both ...two-dimensional and full three-dimensional cases have been investigated in order to provide a suitable tool for geometrical optimization of this rotor. Unsteady simulations are carried out at different tip speed ratio (TSR), varying angular speed of rotor at constant wind speed, using different one and two-equation URANS turbulence models and selecting the k−ω SST for the final analysis. The two-dimensional model was compared with experimental data available in literature and obtained from tests in wind tunnel. This simplified model shows an over-estimation of experimental data, reporting a maximum efficiency at TSR 1, 20% higher than experimental value. The results of 3D model are in good agreement with experiments with a peak of 0.202 at TSR 0.8 for a rotor with aspect ratio 1.1. The influence of the rotor height has been evaluated on flow dynamics of the turbine and its power coefficient.
•CFD study to characterise the dynamic behaviour of a Savonius vertical axis wind turbine.•URANS modeling approach with k-ω SST turbulence model in OpenFOAM code.•Analysis at different TSR and angular speed of rotor at constant wind speed.•Over-estimation of experimental data with 2D approach, good agreement with 3D approach.•Evaluation of influence of the rotor height on fluid dynamics and power coefficient.
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•Algal cell permeabilization was achieved by applying pulsed electric field.•A synergistic effect was observed at 55°C for the release of carbohydrates by PEF.•PEF allows selective ...release of small water soluble components.•Over 95% of proteins are retained inside the microalgal cell after PEF.
The synergistic effect of temperature (25–65°C) and total specific energy input (0.55–1.11kWhkgDW−1) by pulsed electric field (PEF) on the release of intracellular components from the microalgae Chlorella vulgaris was studied. The combination of PEF with temperatures from 25 to 55°C resulted in a conductivity increase of 75% as a result of cell membrane permeabilization. In this range of temperatures, 25–39% carbohydrates and 3–5% proteins release occurred and only for carbohydrate release a synergistic effect was observed at 55°C. Above 55°C spontaneous cell lysis occurred without PEF. Combined PEF–temperature treatment does not sufficiently disintegrate the algal cells to release both carbohydrates and proteins at yields comparable to the benchmark bead milling (40–45% protein, 48–58% carbohydrates).
Abstract
Ultraviolet spectra were taken of 25 detached eclipsing binaries (DEBs) with spectral types O, B, and early A with the International Ultraviolet Explorer satellite in the 1150–1900 Å region. ...The spectra were compared with BOSZ model atmospheres. The composite spectra of the DEBs were modeled by a combination of models representing the hot and cool components, and the temperatures of the hottest components of the systems were determined. From these temperatures a direct mass–temperature relation was obtained for stars close to the main sequence with solar metallicity for B and early A stars: log
M/M
⊙
= −5.90 ± 0.27 + (1.56 ± 0.07) × log
T
. This relation allows a mass to be inferred for comparable stars from an ultraviolet spectrum. The five chemically peculiar Am stars in the sample have larger radii than normal A stars of the same mass.
In this work, optimal pulsed electric fields-assisted extraction conditions were selected in order to intensify the extractability of polyphenol compounds with high antioxidant activity from potato ...peels. Effectiveness of PEF as cell disintegration technique was confirmed using both impedance measurements and scanning electron microscopy (SEM). Solid-liquid extraction (SLE) for both untreated and PEF pre-treated potato peels was optimized to determine the most effective solvent concentration (0–100% ethanol in water) as well as extraction temperature (20–50 °C) and time (30–240 min) using response surface methodology. Total phenolic compounds (TPC) and antioxidant activity (DPPH) of the extracts were determined. Results showed that the application of PEF prior to SLE has the potential to reduce duration, temperature, and consumption of solvent to achieve the same recovery yield of phenolic compounds. Under optimized conditions (54% ethanol, 233 min, and 50 °C for SLE; 52% ethanol, 230 min, and 50 °C for PEF), the extracts obtained from PEF pre-treated samples showed higher total phenolics yield (10%) and antioxidant activity (9%) as compared to the control extraction. Finally, HPLC-DAD analysis revealed the major classes of the detected polyphenolic compounds as chlorogenic, caffeic, syringic, protocatechuic, and
p
-coumaric acids, and no significant degradation of individual polyphenols due to PEF application was observed.
We study the real-time dynamics of vortices in a large elongated Bose-Einstein condensate (BEC) of sodium atoms using a stroboscopic technique. Vortices are produced via the Kibble-Zurek mechanism in ...a quench across the BEC transition and they slowly precess keeping their orientation perpendicular to the long axis of the trap as expected for solitonic vortices in a highly anisotropic condensate. Good agreement with theoretical predictions is found for the precession period as a function of the orbit amplitude and the number of condensed atoms. In configurations with two or more vortices, we see signatures of vortex-vortex interaction in the shape and visibility of the orbits. In addition, when more than two vortices are present, their decay is faster than the thermal decay observed for one or two vortices. The possible role of vortex reconnection processes is discussed.
This work focuses on Savonius turbine numerical modeling and mutual turbine interaction in a linear array farm. Two-dimensional Computational Fluid Dynamics modeling was carried out using the open ...source solver OpenFOAM. Results are compared with available experimental data and three-dimensional CFD modeling. The influence of main parameters, such as the distance between adjacent turbines, the wind incidence angle and the number of turbines is investigated and the linear array efficiency is defined. The obtained results show a performance increase as the distance between the turbines reduces, higher efficiency for small wind incidence angles, and a larger number of turbines.
•CFD study to characterise the interaction effect between multiple Savonius turbines.•URANS modeling approach with k-omega SST turbulence model in OpenFOAM code.•Analysis at different distance between rotors and the number of turbines.•Increase in performance with the reduction of the distance between rotors.•Influence of wind incident direction and number of turbines on the array performance.
This paper deals with the problem of designing a distributed fault detection and isolation methodology for nonlinear uncertain large-scale discrete-time dynamical systems. As a divide et impera ...approach is used to overcome the scalability issues of a centralized implementation, the large scale system being monitored is modelled as the interconnection of several subsystems. The subsystems are allowed to overlap, thus sharing some state components. For each subsystem, a Local Fault Diagnoser is designed, based on the measured local state of the subsystem as well as the transmitted variables of neighboring states that define the subsystem interconnections. The local diagnostic decision is made on the basis of the knowledge of the local subsystem dynamic model and of an adaptive approximation of the interconnection with neighboring subsystems. The use of a specially-designed consensus-based estimator is proposed in order to improve the detectability and isolability of faults affecting variables shared among overlapping subsystems. Theoretical results are provided to characterize the detection and isolation capabilities of the proposed distributed scheme. Finally, simulation results are reported showing the effectiveness of the proposed methodology.
In order to function properly, the brain must be wired correctly during critical periods in early development. Mistakes in this process are hypothesized to occur in disorders like autism and ...schizophrenia. Later in life, signaling pathways are essential in maintaining proper communication between neuronal and non-neuronal cells, and disrupting this balance may result in disorders like Alzheimer's disease. The Wnt/beta-catenin pathway has a well-established role in cancer. Here, we review recent evidence showing the involvement of Wnt/beta-catenin signaling in neurodevelopment as well as in neurodegenerative diseases. We suggest that the onset/development of such pathological conditions may involve the additive effect of genetic variation within Wnt signaling components and of molecules that modulate the activity of this signaling cascade.
Using a multiple-image reconstruction method applied to a harmonically trapped Bose gas, we determine the equation of state of uniform matter across the critical transition point, within the local ...density approximation. Our experimental results provide the canonical description of pressure as a function of the specific volume, emphasizing the dramatic deviations from the ideal Bose gas behavior caused by interactions. They also provide clear evidence for the nonmonotonic behavior with temperature of the chemical potential, which is a consequence of superfluidity and Bose-Einstein condensation. The measured thermodynamic quantities are compared to mean-field predictions available for the interacting Bose gas. The limits of applicability of the local density approximation near the critical point are also discussed, focusing on the behavior of the isothermal compressibility.
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