Miracle-dz/UniFAR-FTUs huggingface dataset:
Orbit modeling of fast particle redistribution induced by sawtooth instability

Initial tests on the National Spherical Torus Experiment Upgrade (NSTX-U) (Menard et al 2012 Nucl. Fusion 083015) device suggest that introducing energy selectivity for sawtooth induced fast ion redistribution is required to improve the agreement between experimental and simulated quantities such as neutron rate and Fast-Ion D-Alpha profiles. The aim of this work is to assess the requirements to properly describe the behaviour of fast ions during a sawtooth crash for predictive sawtooth simulations. As the first step, in this work, we use the particle-following Orbit code to characterize the redistribution of fast particles. In order for a sawtooth crash to be simulated, a spatial and temporal displacement is implemented into the Orbit code. The perturbation amplitude is determined by comparison with experimental measurement of the neutron rate drop. The characteristics of fast ions with different orbit types are investigated in phase and real space. Due to a sawtooth crash, fast ion energy and angular momentum are modified resulting in the redistribution in phase space and orbit type change. The redistribution of fast ions in real space shows that the sawtooth instability brings different effect on fast particles with different orbit types as observed in experiments. The initial interpretative Transp simulation using the so-called kick model based on the Orbit modeling result shows an improvement of fast ion redistribution before and after a sawtooth crash but the neutron rate still has discrepancy compared to the experimental measurement.
Rheological Behavior of Fresh Cement Pastes

Rheology of a concrete is mainly controlled by the rheological behavior of its cement paste. This is the main practical reason for the extensive research activity observed during 70 years in this research subfield. In this brief review, some areas of the research on the rheological behavior of fresh cement pastes (mixture method influence, microstructure analysis, mineral additions influence, chemical additives influence, blended cements behavior, viscoelastic behavior, flow models, and flow behavior analysis with alternative methods) are examined.
Poleward propagation of near-inertial waves induced by fluctuating winds over a baroclinically unstable zonal jet

We investigate the excitation and radiation of near-inertial internal gravity waves continuously excited by a latitudinally confined temporally fluctuating wind in a numerical model of a stratified ocean on a $\unicode[STIX]{x1D6FD}$ -plane at mid-latitude. The surface wind forcing contains both high- and low-frequency components which excite propagating waves and a baroclinically unstable zonal jet respectively. Wentzel–Kramers–Brillouin (WKB) ray theory implies that near-inertial waves propagate strictly towards the equator. We seek to refine this view here by (i) adding the non-traditional Coriolis force (accounting for the horizontal component of the Earth’s rotation) into the equations of motion, in order to allow poleward sub-inertial propagation to occur, and (ii) relaxing the conceptual constraint of no zonal variability, to allow the zonal jet to undergo instability, to meander and to sustain an active field of mesoscale eddies, potentially impacting the excitation of near-inertial waves. The key results are that, while (i) permits weakly stratified waveguides with sub-inertial poleward wave propagation to develop in accord with theory, the sub-inertial energy flux observed is very small compared with the equatorward flux. Thus, in terms of energy radiated from the storm track, non-traditional effects are small for wind-driven near-inertial waves. The consequences of (ii) are much more pronounced. Refinement (ii) produces a radiating wave field that is bidirectional, i.e. with both poleward and equatorward components. We show that the presence of regions of significant background vorticity with horizontal scales significantly smaller than the width of the storm track provides the scale selection mechanism to excite waves with sufficiently super-inertial frequencies to propagate poleward distances of the order of 1000 km.
TELECOM ParisTech Spécialité « Electronique et Communications » présentée et soutenue publiquement par New Ways of Exploiting Feedback in Memoryless Broadcast Channels

In this dissertation we investigate the usefulness of feedback and propose new ways of exploiting rate-limited feedback for the memoryless broadcast channels (BC). In the first part of the dissertation, we consider K-reciever Gaussian BC with only common message and feedback. We show that linear-feedback schemes with a message point, in the spirit of the Schalkwijk-Kailath scheme, are strictly suboptimal for this setup. To contrast this negative result, we describe a scheme for rate-limited feedback that uses the feedback in an intermittent way, which achieves all rates R up to capacity C with an L-th order exponential decay of the probability of error if the feedback rate is no smaller than (L-1)R, for some positive integer L. In the second part, we study the two-receiver DMBC with private messages and rate-limited feedback. Two types of schemes based on block-Markov strategy and Marton's coding, have been proposed for this setup. In the first type of scheme, the transmitter simply relays the feedback messages obtained over the feedback links by encoding them into the Marton cloud center of the next-following block. With this type of scheme, we show that any positive feedback rate can strictly improve over the non-feedback capacity region for the class of strictly essentially less-noisy BCs, which we introduce in this dissertation. In our second type of scheme, the transmitter decodes all the feedback information and processes it with some local information before sending the result to the receivers. When the feedback rates are sufficiently large, then our scheme can recover all previously results of capacity region and degrees of freedom for memoryless BCs with feedback.
Further experiments for mean velocity profile of pipe flow at high Reynolds number

This paper reports further experimental results obtained in high Reynolds number actual flow facility in Japan. The experiments were performed in a pipe flow with water, and the friction Reynolds number was varied up to Reτ = 5.3 × 104. This high Reynolds number was achieved by using water as the working fluid and adopting a large-diameter pipe (387 mm) while controlling the flow rate and temperature with high accuracy and precision. The streamwise velocity was measured by laser Doppler velocimetry close to the wall, and the mean velocity profile, called log-law profile U+ = (1/κ) ln(y+) + B, is especially focused. After careful verification of the mean velocity profiles in terms of the flow rate accuracy and an evaluation of the consistency of the present results with those from previously measurements in a smaller pipe (100 mm), it was found that the value of κ asymptotically approaches a constant value of κ = 0.384. This paper reports further experimental results obtained in high Reynolds number actual flow facility in Japan. The experiments were performed in a pipe flow with water, and the friction Reynolds number was varied up to Reτ = 5.3 × 104. This high Reynolds number was achieved by using water as the working fluid and adopting a large-diameter pipe (387 mm) while controlling the flow rate and temperature with high accuracy and precision. The streamwise velocity was measured by laser Doppler velocimetry close to the wall, and the mean velocity profile, called log-law profile U+ = (1/κ) ln(y+) + B, is especially focused. After careful verification of the mean velocity profiles in terms of the flow rate accuracy and an evaluation of the consistency of the present results with those from previously measurements in a smaller pipe (100 mm), it was found that the value of κ asymptotically approaches a constant value of κ = 0.384.
Synthesis of multi-polarised upside conical frustum array antenna for 5G mm-Wave base station at 28/38 GHz

In this study, a multi-polarised millimetre-wave (mm-Wave) base station operating at 28/38 GHz is introduced for future fifth generation (5G) mobile communication networks. The proposed station employs 32-element array antenna distributed in upside conical frustum configuration (UCFC) to synthesise multi-beam patterns adopting directivity and polarisation control. First, the design of dual-band circularly polarised antenna element at 28/38 GHz is discussed. The measured results show that the designed antenna element has a reflection coefficient less than -23 dB with a realised antenna gain of 8 dBi, on average, in the assigned frequency bands. Based on the designed antenna element, the antenna array performance is studied in terms of gain, radiation efficiency, reflection coefficient, and coverage efficiency. The results are compared with those obtained from 32-element structured in an octagonal prism configuration (OPC). For antenna design parameters and multi-beam pattern synthesis, a modified version of hybrid gravitational search algorithm and particle swarm optimisation is proposed. It is found that, the introduced UCFC outperformed the OPC by 19.8%. Moreover, distributing the antenna array in UCFC improved the convergence by 21.7% compared to OPC.
Design and Test of an Ultra-Low Solidity Flow-Controlled Compressor Stator

A full annulus fluidic flow-controlled compressor stator ring was designed and tested in the third stage of a four-stage low speed research compressor. The solidity of the flow-controlled stator was near unity and significantly below design practice with a commensurately high diffusion factor. The design intent was to reduce the vane count by 30% and load the stator to the point of stall at the design point then employ flow control to restore attached boundary layers and regain design-point stage-matching. The flow control applied that maintained attached flow was 1% of the compressor mass flow and was introduced via discrete steady jets on the suction side of the stator. The design method used steady CFD with the flow control jets simulated to drive stator exit angles, velocities and blockage to match the baseline machine. The experiment verified the pre-test predictions and demonstrated degraded compressor performance without flow control and restoration of the pumping characteristics of the baseline high solidity compressor when flow control was applied. An assessment of the engine cycle impact of the flow-controlled compressor shows the stage efficiency trade for the increased loading was 2.1 points. Extrapolation of the data and analysis to a high-speed compressor shows a more modest 0.5 points stage efficiency trade.Copyright © 2004 by ASME
The Central Kiloparsec of Starbursts and AGN : The La Palma Connection

From May 7 to 11, 2001, the Hotel Hacienda San Jorge in the small resort town of Los Cancajos on La Palma was filled with astronomers studying the central kiloparsec regions of starbursts and AGN. La Palma is one of the smallest of the Spanish Canary Islands and is well known for its world-class astronomical observatory at the Roque de los Muchachos. The main telescopes operated there are the Isaac Newton Group’s 4.2m William Herschel Telescope and the Italian 3.5m National Telescope, while Spain is presently constructing its 10.4m telescope, Grantecan. In spite of a strong astronomical presence of at least two decades, this was the first scientific astronomy conference organized completely on La Palma. The fact that many high-resolution studies of galaxies have been made using data obtained on La Palma makes the island a fitting “connection” to the field of study. The meeting was attended by 120 astronomers from 15 countries, while a number of people had to be disappointed because the capacity of the hotel and conference room would not allow more attendees. The program was full and included nine oral and two poster sessions, long lunch breaks, which were often used for further discussions or collaborative work, and a number of social events. Most of those attending participated in a guided tour of the telescopes at the Observatory on the Wednesday afternoon.
A rate-pressure-dependent thermodynamically-consistent phase field model for the description of failure patterns in dynamic brittle fracture

The investigation of failure in brittle materials, subjected to dynamic transient loading conditions, represents one of the ongoing challenges in the mechanics community. Progresses on this front are required to support the design of engineering components which are employed in applications involving extreme operational regimes. To this purpose, this thesis is devoted to the development of a framework which provides the capabilities to model how crack patterns form and evolve in brittle materials and how they affect the quantitative description of failure. The proposed model is developed within the context of diffusive interfaces which are at the basis of a new class of theories named phase field models. In this work, a set of additional features is proposed to expand their domain of applicability to the modelling of (i) rate and (ii) pressure dependent effects. The path towards the achievement of the first goal has been traced on the desire to account for micro-inertia effects associated with high rates of loading. Pressure dependency has been addressed by postulating a mode-of-failure transition law whose scaling depends upon the local material triaxiality. The governing equations have been derived within a thermodynamically-consistent framework supplemented by the employment of a micro-forces balance approach. The numerical implementation has been carried out within an updated lagrangian finite element scheme with explicit time integration. A series of benchmarks will be provided to appraise the model capabilities in predicting rate-pressure-dependent crack initiation and propagation. Results will be compared against experimental evidences which closely resemble the boundary value problems examined in this work. Concurrently, the design and optimization of a complimentary, improved, experimental characterization platform, based on the split Hopkinson pressure bar, will be presented as a mean for further validation and calibration.
Longtime robustness and semi-uniform compactness of a pullback attractor via nonautonomous PDE

This paper is concerned with the robustness of a pullback attractor as the time tends to infinity. A pullback attractor is called forward (resp. backward) compact if the union over the future (resp. the past) is pre-compact. We prove that the forward (resp. backward) compactness is a necessary and sufficient condition such that a pullback attractor is upper semi-continuous to a compact set at positive (resp. negative) infinity, and also obtain the minimal limit-set. We further prove the lower semi-continuity of the pullback attractor and get the maximal limit-set at infinity. Some criteria for such robustness are established when the evolution process is forward or backward omega-limit compact. Those theoretical criteria are applied to prove semi-uniform compactness and robustness at infinity in pullback dynamics for a Ginzburg-Landau equation with variable coefficients and a forward or backward tempered nonlinearity.
Input‐Output Decoupling of Boolean Control Networks

This paper is devoted to the input‐output decoupling problem of Boolean control networks (BCNs). First, a necessary and sufficient condition for the existence of comparable output subspaces is obtained as well as an algorithm to construct the comparable output subspaces. Then, two kinds of controllers are designed to solve the decoupling problem, including open‐loop controller and state feedback controller. Finally, an example is given to illustrate the effectiveness of the proposed method.
Effect of external electric and magnetic field on propagation of atmospheric pressure plasma jet

The behaviors of atmospheric pressure plasma jet produced by a coplanar dielectric barrier discharge (CDBD) in helium in external electrostatic and magnetic field are investigated experimentally. Time-resolved ICCD images of jet in electric field, magnetic field, and floating metal ring are recorded, respectively. The results show that the jet dynamics is affected significantly by a metal ring, an electric, and/or a magnetic field. In a transverse electric field, the jet shows behavior of deflection, broadening, and shortening according to the structure of electric field. In a transverse magnetic field, the jet deflects to up or down depending on the magnetic direction. The jet can be slowed down or obstructed by a floating metal ring on the jet path, but will still pass through the tube at higher applied voltages of DBD, without significant change in jet length or shape out of the tube compared with that without metal ring. A positive DC voltage on the metal ring helps to improve the jet length, but a ne.
Advanced response of Baikal macroscopic nonlocal correlation detector to solar activity

The long-term Baikal Deep-Sea Experiment on study of macroscopic entanglement and advanced response of nonlocal correlation detectors to natural random dissipative processes is conducting. There are both advanced and retarded nonlocal correlations, which correspond to the same direction of causality. However, time reversal causality prevails over usual time respecting one. It is the most prominent property of macroscopic entanglement and manifestation of quantum principle of weak causality. In particular, there is an advanced response to the random component of solar activity, which can be used for the forecast of this component.
STOCHASTIC ANALYSIS OF TIDAL DYNAMICS EQUATION

In this paper the deterministic and stochastic tidal equation in 2-D have been studied. The main results of this work are the existence and uniqueness theorem for strong solutions. These results are obtained by utilizing a global monotonicity property of the sum of the linear and nonlinear operators and exploiting the generalized Minty-Browder technique.
Dynamic analysis of the interactions between a low-to-medium-speed maglev train and a bridge: Field test results of two typical bridges

The rated suspension gap of a low-to-medium-speed maglev train with electromagnetic suspension is normally 8–10 mm. However, while either passing over a bridge or being stationary on one, the maglev train deforms the bridge and therefore alters the suspension gap. Hence, a problem arises due to coupled vibrations between the maglev train and its supporting bridge. In the study reported here, field experiments were conducted on the Chinese Changsha maglev line, which was the first commercial low-to-medium-speed maglev line in China. The focus is on two types of pre-stressed double-track concrete bridges on the maglev line. One is a simply supported girder with a span of 25 m, while the other is a continuous girder designed as 25 + 35 + 25 m. The accelerations and vertical dynamic deflections of the two bridges at midspan were measured while a five-module low-to-medium-speed maglev train with electromagnetic suspension either passed over or was stationary on either bridge, as were the accelerations of the car body and the suspension frame. The basic dynamic characteristics of the two bridges are analysed and compared with those of bridges in various typical maglev lines. The vibration characteristics of the two bridges, the car body and the suspension frame are studied in the time and frequency domains for the maglev train running at normal speeds, low speeds and when stationary. The influences of the speed on the dynamic characteristics are discussed. Some comparisons with other studies are also carried out, including the effects of bridge parameters on the coupled vibrations and the running stability of a low-to-medium-speed maglev and a CRH2C wheel/rail train. Significant conclusions are drawn from the analysis: increasing the rigidity and mass of the bridge can significantly reduce its vibration; increasing the span and deflection of the bridge increases the vibrations of the car body and the suspension frame; the dynamics of the maglev vehicle and bridges are different when the maglev train runs at normal speeds (more than 30 km/h), low speeds (less than 30 km/h) and when being stationary. The running stability of a low-to-medium-speed maglev train is better than that of a CRH2C high-speed train. The present study provides a test basis for further research on the mechanisms for coupled vibrations of maglev train–bridge systems.
Radar-Derived Structural and Precipitation Characteristics of ZDR Columns within Warm-Season Convection over the United Kingdom

Analyses of the radar-observed structure and derived rainfall statistics of warm-season convection developing columns of enhanced positive differential reflectivity ZDR over England’s southwest peninsula are presented here. Previous observations of ZDR columns in developing cumulonimbus clouds over England were rare. The observations presented herein suggest otherwise, at least in the southwesterly winds over the peninsula. The results are the most extensive of their kind in the United Kingdom; the data were collected using the National Centre for Atmospheric Science dual-polarization X-band radar (NXPol) during the Convective Precipitation Experiment (COPE). In contrast to recent studies of ZDR columns focused on deep clouds that developed in high-instability environments, the COPE measurements show relatively frequent ZDR columns in shallower clouds, many only 4–5 km deep. The presence of ZDR columns is used to infer that an active warm rain process has contributed to precipitation evolution in convection deep enough for liquid and ice growth to take place. Clouds with ZDR columns were identified objectively in three COPE deployments, with both discrete convection and clouds embedded in larger convective complexes developing columns. Positive ZDR values typically extended to 1–1.25 km above 0°C in the columns, with ZDR ≥ 1 dB sometimes extending nearly 4 km above 0°C. Values above 3 dB typically occurred in the lowest 500 m above 0°C, with coincident airborne measurements confirming the presence of supercooled raindrops. Statistical analyses indicated that the convection that produced ZDR columns was consistently associated with the larger derived rainfall rates when compared with the overall convective population sampled by the NXPol during COPE.