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International audience; Cet article, inscrit notamment dans une approche d’archéologie des médias, analyse les spécificités de l’émergence d’un nouveau média, la plateforme de streaming musicale, à partir d’une comparaison avec la radio musicale, en prenant deux exemples français : Deezer et FIP. La comparaison s’appuie sur la notion de stockage et l’agencement du stockage avec le flux. Ce rapport entre flux et stockage permet d’expliciter le mouvement de convergence entre fournisseurs de flux musicaux et d’interroger la distinction entre ces deux logiques, qui tend à se brouiller en régime numérique.

Ammonium (NH4+)-based fertilization efficiently mitigates the adverse effects of nitrogen fertilization on the environment. However, high concentrations of soil NH4+ provoke growth inhibition, partly caused by the reduction of cell enlargement and associated with modifications of cell composition, such as an increase of sugars and a decrease in organic acids. Cell expansion depends largely on the osmotic-driven enlargement of the vacuole. However, the involvement of subcellular compartmentation in the adaptation of plants to ammonium nutrition has received little attention, until now. To investigate this, tomato (Solanum lycopersicum) plants were cultivated under nitrate and ammonium nutrition and the fourth leaf was harvested at seven developmental stages. The vacuolar expansion was monitored and metabolites and inorganic ion contents, together with intracellular pH, were determined. A data-constrained model was constructed to estimate subcellular concentrations of major metabolites and ions. It was first validated at the three latter developmental stages by comparison with subcellular concentrations obtained experimentally using non-aqueous fractionation. Then, the model was used to estimate the subcellular concentrations at the seven developmental stages and the net vacuolar uptake of solutes along the developmental series. Our results showed ammonium nutrition provokes an acidification of the vacuole and a reduction in the flux of solutes into the vacuoles. Overall, analysis of the subcellular compartmentation reveals a mechanism behind leaf growth inhibition under ammonium stress linked to the higher energy cost of vacuole expansion, as a result of alterations in pH, the inhibition of glycolysis routes and the depletion of organic acids. TP benefited from a cotutelle PhD (University of Bordeaux and University of the Basque Country) and thanks the University of the Basque Country (UPV/EHU, Spain) for his PhD grant during the execution of this work. This research was financially supported by the Basque Government (IT-932-16) and the Spanish Government (BIO2017-84035-R co-funded by Fondo Europeo para el Desarrollo Regional [FEDER]). Analytics were supported by MetaboHUB (ANR-11-INBS-0010) and PHENOME (ANR-11-INBS-0012) projects. Technical support was provided by Cedric Cassan, Ana Renovales and Mandy Bordas. The authors also thank SGIker (UPV/EHU, FEDER, EU) for the technical and human support provided.

This paper reveals the flux leakage design and modeling principle of a flux leakage controllable permanent magnet (FLC-PM) machine by considering driving cycles. The key is to obtain the relationship between flux leakage characteristics and multiple operating conditions. Based on the flux leakage controllable concept, an FLC-PM machine with an artfully designed flux leakage region is proposed. The design principle of the machine is investigated by analyzing the magnetic circuit of the machine in multiple operating conditions. The flux leakage factor is introduced to characterize the variable magnetic field in multiple operating conditions. On this basis, the mathematical model of the FLC-PM machine is deduced, and the driving characteristics of the machine are studied in detail. In order to evaluate the presented principle of the FLC-PM machine, a prototype is manufactured for experiments. Through the theoretical analysis and experimental testing, it is verified that the proposed principle is feasible and effective.

This work focuses on the numerical solution of hyperbolic conservations laws (possibly endowed with a source term) using the Active Flux method. This method is an extension of the finite volume method. Instead of solving a Riemann Problem, the Active Flux method uses actively evolved point values along the cell boundary in order to compute the numerical flux. Early applications of the method were linear equations with an available exact solution operator, and Active Flux was shown to be structure preserving in such cases. For nonlinear PDEs or balance laws, exact evolution operators generally are unavailable. Here, strategies are shown how sufficiently accurate approximate evolution operators can be designed which allow to make Active Flux structure preserving / well-balanced for nonlinear problems.

Four oceanographic moorings were deployed across the South China Sea continental slope near 21.85∘ N, 117.71∘ E, from 30 May to 18 July 2014​​​​​​​ for the purpose of observing high-frequency nonlinear internal waves (NLIWs) as they shoaled across a rough, gently sloping bottom. Individual waves required just 2 h to traverse the array and could thus easily be tracked from mooring to mooring. In general, the amplitude of the incoming NLIWs tracked the fortnightly tidal envelope in the Luzon Strait; they lagged by 48.5 h and were smaller than the waves previously observed to the southwest near the Dongsha Plateau. Two types of waves, a waves and b waves,​​​​​​​ were observed, with the b waves always leading the a waves by 6–8 h. Most of the NLIWs were remotely generated, but a few of the b waves formed locally via convergence and breaking at the leading edge of the upslope-propagating internal tide. Waves incident upon the moored array with amplitude less than 50 m and energy less than 100 MJ m−1 propagated adiabatically upslope with little change of form. Larger waves formed packets via wave dispersion. For the larger waves, the kinetic energy flux decreased sharply upslope between 342 and 266 m, while the potential energy flux increased slightly, causing an increasing ratio of potential-to-kinetic energy as the waves shoaled. None of the waves met the criteria for convective breaking. The results are in rough agreement with recent theory and numerical simulations of shoaling waves.

Le paysage de la danse contemporaine évolue sans cesse, particulièrement au cours des trente dernières années. Le glissement progressif des compagnies de répertoire vers un assemblage hétéroclite de créateur·rices indépendant·es appelle l’interprète à maîtriser des compétences de plus en plus complexes. Étant donné ce changement de paradigme, quelle préparation privilégier dans les institutions de formation ? Pour répondre à la question, j’ai développé le « corps poreux », une structure de sensation pour cultiver la malléabilité physique et mentale avec quatre principes directeurs : le flux, le jeu, la métaphore et le paradoxe. À partir de ma pratique en interprétation, en chorégraphie et en enseignement, ainsi que des recherches d’artistes de danse, de praticien·nes du mouvement et de psychologues des XXe et XXIe siècles, je décris cette méthode et partage des réactions empiriques des interprètes avec qui je l’ai expérimentée. Contemporary dance is constantly evolving. Its landscape has transformed and developed significantly over the past thirty years, shifting from repertory companies to an eclectic scene of independent choreographers. Dancers need to master a progressively complex set of skills. How should training institutions best prepare students for this paradigm shift? To address this challenge, I began developing “The Porous Body,” a structure of feeling that promotes the practice of heightened physical and mental malleability through four guiding principles: flow, playfulness, metaphor and paradox. Sourcing from my performative, choreographic and pedagogical practices, and the work of dance artists, movement practitioners, and psychologists from the twentieth and twenty-first centuries, I articulate this method and share anecdotal feedback collected from dancers with whom I have recently experimented the concept of physical and mental malleability.

Based on the study of the chemical composition and analysis of the physicochemical properties of waste from a number of metallurgical enterprises in the Zaporizhzhya region, the possibility of using waste as charge materials for the production of magnesium-based alloys has been established. The possibility of using solid salt chlorinator melt (SCM) from ZTMC as a flux in the smelting of magnesium alloy instead of the flux VI-2 has been studied; its effect on the structure and mechanical properties of casting was investigated. The technological possibility of using these chloride wastes in the smelting of the ML5 alloy is shown. It was established that the use of SCM as a flux in the smelting of magnesium alloy contributes to the grinding of the structure and improvement of the mechanical properties of the metal of experimental smelting. The possibility of modification of foundry magnesium alloy with graphite powder (GP), which is the waste from JSC "Ukrgrafit", is investigated. It is shown that the optimal GP additive in the volume of 0.05...0.3% contributes to the grinding of metal grain and increases its strength characteristics due to additional strengthening of both solid solution and eutectoid. It is established that carbon changes the parameters of eutectic transformation, as a result of which, with an increase in its concentration in the alloy, the volume of eutectoid of type δ+γ (Mg4Al3) decreases markedly. Testing the proposed waste for the smelting of the M5 alloy showed that no changes in melting technology are required while the environmental safety of the devised technological process meets the established standards; their quality was improved while increasing the strength limit by 25%, and plasticity by 30%. At the same time, the use of waste in the smelting of magnesium alloys can reduce costs in its production, and improve the environmental situation due to the fact that waste is not disposed of at landfills but reused in metallurgical industries

For interior permanent magnet synchronous motor (IPMSM) drives, accurate torque control and loss-minimizing operation are essential issues to keep up the excellent features of IPMSM. However, flux linkage variations owing to various operating conditions make it challenging to maintain their efficiency at the highest level during overall operating conditions. In this paper, a real-time torque control is proposed to satisfy both torque control accuracy and high-efficiency operation in consideration of flux linkage variations. Firstly, torque control under the minimum copper-loss is modeled as a constrained optimization problem to satisfy both torque reference tracking and loss-minimizing operation in both maximum torque per ampere (MTPA) and flux-weakening regions. Current references are calculated through robust numerical and region identification algorithms in a command optimizer. Moreover, both stator flux linkages and dynamic inductances are estimated to reflect the flux variations in real-time, which is the parts of a parameter estimator. The proposed estimators are designed to extract fundamental flux linkages and their variations while maintaining high dynamic performance. The performance of the proposed methods is verified by simulation and experimental results where premade look-up tables are not utilized at all.

Due to the second order harmonic in the phase voltage, the voltage peak value is much higher than the amplitude of its fundamental component in the 6/4 variable flux reluctance machines (VFRMs). Conventionally, the amplitude of the fundamental component in the phase voltage is used to calculate the voltage constraint in flux-weakening control, which results in a large voltage margin and reduces the DC link voltage utilization. To deal with this problem in the VFRMs, the flux-weakening control considering the second order harmonic of the phase voltage is proposed in this paper. In this method, the voltage peak value is used to calculate the current operating points, by using which the maximum voltage utilization in flux-weakening region can be achieved. It shows by using the proposed method a wider the constant torque region owing to the lower voltage margin in the VFRMs, which exhibits higher power output in flux-weakening region. Finally, the method is verified by the test results in the VFRM.

Tool condition monitoring (TCM) is one of the most relevant tasks during a machining process. Latest high-quality productivity standards make it essential to monitor the cutting tool wearing. Current TCM methodologies demand the installation of sensors near the working area, which in practical terms, it is not the most optimal solution since the final diagnosis can be disturbed by noisy signals and direct interferences with the machining process. This paper proposes a novel non-invasive methodology based on the time-frequency analysis of the stray flux captured around the spindle-motor to detect and estimate the wearing level in cutting tools. Moreover, a new fault indicator based on this quantity is introduced through the application of the discrete wavelet transform (DWT). The results obtained are promising and demonstrates the effectiveness of the proposal to become a complementary source of information to classical approaches. This is validated with a Fanuc Oi mate Computer Numeric Control (CNC) turning machine for three different cutting tool wearing levels and different cutting depths

In this paper, we present the results of the second census of pulsars in the decametre wave range at the Ukrainian T-shaped Radio telescope, second modification (UTR-2). Over the past 10 yr, the worldwide number of discovered nearby pulsars has doubled, which means that there is some urgency to search for a low-frequency radio emission from these newly discovered sources. To increase the sensitivity of this census, the integration time was doubled compared with the first census of 2010–2013. As a result, the decametre radio emission of 20 pulsars was detected, and their flux densities and the shape of their pulses were obtained. The dispersion measures for 10 pulsars and the rotation periods for eight pulsars were refined. For several pulsars, the scattering time constant and FWHM were estimated in the decametre wave range. The upper limits of flux densities for 102 pulsars that have not yet been detected were also estimated.

This paper analyzes the effect of discretization in the frequency-adaptive flux observer (FAO). Although FAO has structural simplicity and ease of implementation, the discrete-time FAO has phase and gain errors in fundamental flux estimation. As a result, the estimated flux might be erroneous, especially in the high-speed region. For accurate flux estimation, this paper analyzes how the voltage synthesis in the pulse-width-modulation (PWM) affects the stator flux. Through the analysis, the backward Euler method is selected for the primitive stator flux estimation. To mitigate the FAOs discretization error, the proposed FAO utilizes the integrators constructed at the rotor reference frame. Since the discretization error comes from the approximation error of the continuous-time integrator at the operating frequency, the proposed FAO conducts the fundamental flux extraction at the rotor reference frame, where the operating frequency components are treated as a dc signal. Thanks to the coordinate transformation, the FAO can be discretized with no error while keeping the structure of double integrators. The proposed method is verified through the computer simulation and experimental test.

A predictive current control with parameter robustness (PR-PCC) method of permanent magnet synchronous motor (PMSM) is proposed in this paper. First, a cost function is designed to calculate the increment of the optimal voltage vector at the current instant, which is based on incremental PMSM model. The incremental PMSM model is used to eliminate the influence of the motor flux parameter. Second, the optimal voltage vector that minimizes the cost function is obtained by combining the increment of optimal voltage vector with the idea of iteration. At the same time, a current observer based on the incremental model is designed to compensate the one-step sampling delay. In this way, the feedback current of dq-axis accurately followed the reference current. In comparison with the conventional pulse width modulation predictive current control (PWM-PCC) method, the proposed method can significantly reduce the steady-state error of dq-axis current caused by inductance, flux and resistance parameters mismatch quickly. Finally, experimental results of the proposed method and the conventional PWM-PCC are presented in this paper to verify the validity of the proposed method.

In sensorless drive of induction motors (IMs), the design of a voltage model (VM) for flux estimation is challenging because of its inherent problems with DC saturation and drift. In the implementation of VM, various strategies have been studied in flux estimator design. The closed-loop (CL) style flux estimator is a popular scheme owing to its good performance in a wide speed range. However, CL style suffers from DC drift problems because of an offset at the back electromotive force. Based on the fact that DC drift always persists in CL style flux estimator, this study proposes an offset extractor (OE) using a parallel structure of two CL style flux estimator. Moreover, a crossover strategy is applied to the comparative flux in CL scheme. This strategy guarantees low speed operation including zero speed. When the proposed OE is applied to the flux estimator in a feedforward manner, the proposed flux estimator exhibits good performance in a wide speed range with robustness to the offset. The proposed OE and flux estimator are compared with conventional methods, and are verified in various situations by simulation and experiment in a sensorless driven IM.

The significant reduction of sediment load flux into Lake Baikal from its main tributary – the Selenga River began in the mid-1970s, and can be explained by climate change and socio-economic activities. Integrated analysis was done of changes in hydro-meteorological parameters (water discharge, sediment load, air temperature, and precipitation) and their tendencies over periods of 1946–1975 (baseline) and 1976–2017 (warming). Changes in natural processes and human activity were negligible during the baseline period. In the warming period, against the background of an increase in temperature, the water discharge had a slight decreasing trend (−13%) whereas the sediment load has significantly decreased (−53%) these are consist with the precipitation change (−9.4%). Analysis of hydro-climatic data using statistical methods showed that in the warming period the greatest reduction in river sediment runoff occurred in the interval 1996–2017. In this period the sediment load was 768 × 103 t/yr, which is less than the average value during the warming period – 1048 × 103 t/yr. Considering sedimentation in the Selenga River delta, the actual sediment load flux from the Selenga River into Lake Baikal amounted to 515 × 103 t/yr, which is three times less than the average multiyear value 1535 × 103 t/yr for observation period (1946–2017).

Due to the motor parameter mismatches, the errors of current sampling circuit, converter nonlinearities and noise, DC bias and high order harmonics exist in flux model, which make the traditional flux observer estimation inaccurate. In this paper, an interior permanent magnet synchronous motors (IPMSM) sensorless drive method based on a five order flux observer is proposed to suppress DC bias and high order harmonics. The proposed five order flux observer can completely remove DC bias and has strong filtering ability for high order harmonics. Additionally, the parameters of the five order flux observer are set through s-domain analysis. Then, the discrete five order flux observer is obtained to better implementation in digital systems, and the discrete five order flux observer is easy to implement. The proposed five order flux observer is verified by experiments on a 2.0-kW IPMSM drive platform.

In this paper, an improved deadbeat predictive stator flux control (DPSFC) based on disturbance observer is proposed to improve the control performance of in-wheel permanent magnet synchronous motors (PMSMs) with parameter mismatch and disturbance. First, the sensitivity of conventional deadbeat predictive current control to the parameter variation, including flux linkage, stator resistance and stator inductance, is analyzed. Then, a reduced-order observer based on additional disturbance state variables is designed to predict the future stator flux and observe the system disturbance caused by parameter mismatch. The proposed DPSFC method is able to enhance the robustness of the drive performance effectively via the compensations of one-step delay and stator voltage. Finally, the performance of the proposed control method is validated by simulations and experiments on a prototype of an in-wheel PMSM drive.

Transpiration is a key process driving energy, water and thus carbon dynamics. Global transpiration products are fundamental for understanding and predicting vegetation processes. However, validation of these transpiration products is limited, mainly due to lack of suitable data sets. We propose a method to use SAPFLUXNET, the first quality-controlled global tree sap flow (SF) database, for evaluating transpiration products at global scale. Our method is based on evaluating temporal mismatches, rather than absolute values, by standardizing both transpiration and SF products. We evaluate how transpiration responses to hydro-meteorological variation from the Global Land Evaporation Amsterdam Model (GLEAM), a widely used global transpiration product, compare to in situ responses from SAPFLUXNET field data. Our results show GLEAM and SAPFLUXNET temporal trends are in good agreement, but diverge under extreme conditions. Their temporal mismatches differ depending on the magnitude of transpiration and are not random, but linked to energy and water availability. Despite limitations, we show that the new global SAPFLUXNET data set is a valuable tool to evaluate T products and identify problematic assumptions and processes embedded in models. The approach we propose can, therefore, be the foundation for a wider use of SAPFLUXNET, a new, independent, source of information, to understand the mechanisms controlling global transpiration fluxes.Plain Language Summary Transpiration, the water evaporating from leaves, is a key element in the energy, water and carbon cycles of terrestrial ecosystems. Understanding patterns of transpiration at global scales is fundamental for prediction of future climates. Several models are used for estimating global transpiration, however identifying limitations and biases in these models is difficult, because we lack field data to compare them against. In this work, we propose a new method to enable tree-level sap flow (SF) data from SAPFLUXNET, the first global SF database, to be used to evaluate transpiration products and models. We evaluated how well GLEAM, a widely used transpiration product, matches SAPFLUXNET field data. We found GLEAM and SAPFLUXNET data to be in reasonable agreement however, mismatches occur under extreme dry or wet meteorological conditions, conditions which are likely to become more common under future climates. The detection of mismatches between SAPFLUXNET and GLEAM data is valuable for the identification of model processes and assumptions which could be reasonable within current climate, but inadequate for future climate conditions. The method we propose allows the use of SAPFLUXNET to understand the true mechanisms controlling global transpiration providing a new, independent, source of information to evaluate transpiration products and models.

The article describes the technology of repair of internal combustion engine block and engine block parts, i.e. defect detection, diagnosis and repair.

A deep survey of the Large Magellanic Cloud at ~0.1-100TeV photon energies with the Cherenkov Telescope Array is planned. We assess the detection prospects based on a model for the emission of the galaxy, comprising the four known TeV emitters, mock populations of sources, and interstellar emission on galactic scales. We also assess the detectability of 30 Doradus and SN 1987A, and the constraints that can be derived on the nature of dark matter. The survey will allow for fine spectral studies of N157B, N132D, LMC P3, and 30 Doradus C, and half a dozen other sources should be revealed, mainly pulsar-powered objects. The remnant from SN 1987A could be detected if it produces cosmic-ray nuclei with a flat power-law spectrum at high energies, or with a steeper index 2.3-2.4 pending a flux increase by a factor >3-4 over ~2015-2035. Large-scale interstellar emission remains mostly out of reach of the survey if its >10GeV spectrum has a soft photon index ~2.7, but degree-scale 0.1-10TeV pion-decay emission could be detected if the cosmic-ray spectrum hardens above >100GeV. The 30 Doradus star-forming region is detectable if acceleration efficiency is on the order of 1-10% of the mechanical luminosity and diffusion is suppressed by two orders of magnitude within, Accepted for publication in MNRAS. Corresponding authors: Pierrick Martin, Maria Isabel Bernardos Martin, Fabio Iocco

A major strong sudden stratospheric warming (SSW) occurred in the Southern Hemisphere (SH) stratosphere in 2002 (hereafter referred to as SSW2002), which is one of the most unusual winters in the SH. Following several warmings, the polar vortex broke down in midwinter. Eastward-traveling waves and their interaction with quasi-stationary planetary waves played an important role during this event. This study analyzed the Japanese 55-year reanalysis (JRA-55) dataset to examine the SSW event that occurred in the SH in 2019 (hereafter referred to as SSW2019). In 2019, a rapid temperature increase and decelerated westerly winds were observed at the polar cap, but since there was no reversal of westerly winds to easterly winds at 60∘ S in the middle to lower stratosphere, the SSW2019 was classified as a minor warming event. The results showed that quasi-stationary planetary waves of zonal wavenumber 1 developed during the SSW2019. The strong vertical component of the Eliassen–Palm flux with zonal wavenumber 1 is indicative of pronounced propagation of planetary waves to the stratosphere. The wave driving in September 2019 was larger than that of the major SSW event in 2002. Major SSWs tend to accompany preceding minor warmings, preconditioning, which changes the zonal flow that weaken the polar night jet as seen in SSW2002. A similar preconditioning was hardly observed in SSW2019. The strong wave driving in SSW2019 occurred in high latitudes. Waveguides (i.e., positive values of the refractive index squared) were found at high latitudes in the upper stratosphere during the warming period, which provided favorable conditions for quasi-stationary planetary waves to propagate upward and poleward.

We described new sea surface CO2 observations in the south-western Indian Ocean obtained in January 2020 when a strong bloom event occurred south-east of Madagascar and extended eastward in the oligotrophic Indian Ocean subtropical domain. Compared to previous years (1991–2019) we observed very low fCO2 and dissolved inorganic carbon concentrations (CT) in austral summer 2020, indicative of a biologically driven process. In the bloom, the anomaly of fCO2 and CT reached respectively −33 µatm and −42 µmol kg−1, whereas no change is observed for alkalinity (AT). In January 2020 we estimated a local maximum of air–sea CO2 flux at 27∘ S of −6.9 mmol m−2 d−1 (ocean sink) and −4.3 mmol m−2 d−1 when averaging the flux in the band 26–30∘ S. In the domain 25–30∘ S, 50–60∘ E we estimated that the bloom led to a regional carbon uptake of about −1 TgC per month in January 2020, whereas this region was previously recognized as an ocean CO2 source or near equilibrium during this season. Using a neural network approach that reconstructs the monthly fCO2 fields, we estimated that when the bloom was at peak in December 2019 the CO2 sink reached −3.1 (±1.0) mmol m−2 d−1 in the band 25–30∘ S; i.e. the model captured the impact of the bloom. Integrated in the domain restricted to 25–30∘ S, 50–60∘ E, the region was a CO2 sink in December 2019 of −0.8 TgC per month compared to a CO2 source of +0.12 (±0.10) TgC per month in December when averaged over the period 1996–2018. Consequently in 2019 this region was a stronger CO2 annual sink of −8.8 TgC yr−1 compared to −7.0 (±0.5) TgC yr−1 averaged over 1996–2018. In austral summer 2019–2020, the bloom was likely controlled by a relatively deep mixed-layer depth during the preceding winter (July–September 2019) that would supply macro- and/or micro-nutrients such as iron to the surface layer to promote the bloom that started in November 2019 in two large rings in the Madagascar Basin. Based on measurements in January 2020, we observed relatively high N2 fixation rates (up to 18 nmol N L−1 d−1), suggesting that diazotrophs could play a role in the bloom in the nutrient-depleted waters. The bloom event in austral summer 2020, along with the new carbonate system observations, represents a benchmark case for complex biogeochemical model sensitivity studies (including the N2 fixation process and iron supplies) for a better understanding of the origin and termination of this still “mysterious” sporadic bloom and its impact on ocean carbon uptake in the future.

The design rules of winding configurations and stator-pole/rotor-tooth (SP/RT) number combinations of doubly-fed flux-switching permanent magnet (DF-FSPM) machines are investigated in this paper based on coil-EMF vectors. The relationships between the components of stator and rotor coil-EMF vector diagrams are unveiled at first, including the numbers of stator and rotor phases, and the numbers of stator and rotor spokes. Then, the SP/RT number combinations are derived considering feasible stator/rotor phase number combinations and different winding configurations. The SP/RT number combinations are optimized considering the winding factors, magnetic field harmonics, unbalanced magnetic forces and machine diameter. It is shown that both of the stator and rotor pitch factors increase when the SP and RT numbers get closer. Furthermore, the influence of winding configurations and SP/RT number combinations on electromagnetic performances of DF-FSPM machines are analyzed by finite-element method. Finally, the analysis results are validated by experiment.

The flux-switching permanent magnet (FSPM) machine has aroused wide interest recently due to high power density, favorable PM cooling capability, and essentially sinusoidal electromotive-force (EMF) waveform per phase. Previously, the phase back-EMF generation mechanism of FSPM machines is exposed from a flux-switching perspective, however, which is rethought from the viewpoint of air-gap modulation magnetic field in Part I as this paper, and electromagnetic torque generation mechanism of FSPM machines will be reported in Part II as another sister paper. With the aid of magnetic field modulation theory (MFMT), the air-gap PM magnetic field and back-EMF of the FSPM machine are modeled based on modulation and winding functions. Their characteristics are analyzed in detail and consequently, principles concerning FSPM machines on arbitrary stator-slot/ rotor-pole combinations can be obtained, including the basic feature of FSPM machines, the principle and necessary conditions for the back-EMF generation, the fundamental reason of sinusoidal back-EMF waveform, and the contributions of modulation harmonics to phase back-EMF. Finally, experimental verification on a 12s/10p prototyped machine is conducted.

This paper presents a novel linear generator structure of three-phase tubular staggered transverse flux permanent magnet linear generator (TSTF-PMLG) for wave energy conversion. Compared with conventional TF-PMLGs, the new structure has a simpler magnetic flux path, high mechanical strength, low cogging force and more suitable for lowspeed direct driven situation. In the primary of TSTF-PMLG, a nonuniform teeth steel sheets structure is used and steel sheets of different phases are in different angel so that the groove can be separated by staggered steel sheets in the plane perpendicular to the direction of movement. By the analytical model, the operation principle of the motor is explained. Then through the finite element analysis, the distribution of the main flux and leakage flux, the no-load characteristics and output power of TSTF-PMLG are analyzed in detail. And the influence of the lamination factor on the output characteristics of the TSTF-PMLG is obtained. Subsequently the appropriate design parameters of the TSTF-PMLG are selected. During the TSTF-PMLG processing, the method of mixing silicon steel sheets and fiberglass board is used to limiting the lamination factor. Finially, a prototype of 150W rated power and 79% rated efficiency is presented. And the experimental results verify the theoretical analysis.

The introduction of high temperature superconducting (HTS) magnet, which is capable of working at liquid nitrogen temperature, and the use of null-flux coil, make the liquid-helium-free electrodynamic suspension (EDS) train available. In essence, the electromagnetic force of a superconducting EDS train is generated by electromagnetic interaction between the onboard superconducting magnets and the ground null-flux coils. In order to obtain an efficient HTS EDS train, the design optimization of the HTS magnets and null-flux coils is indispensable. This study is devoted to this aspect. We first establish an improved load-line method for efficiently estimating the critical current of HTS magnets and an improved semianalytical model to accurately calculate the induced currents and electromagnetic forces in the EDS train. Based on above two improvements, the onboard HTS magnets and corresponding null-flux coils are then designed and optimized to enhance the overall performances of the HTS EDS train. At final, according to the optimized results, the HTS magnets and null-flux coils were manufactured and measured, followed by the performance analyses of the obtained HTS EDS train. The results have shown that the electromagnetic performances of the designed HTS EDS train are excellent, demonstrating the effectiveness of the optimization methodology.

High-order schemes with larger time-step limits can benefit from using adaptive mesh refinement grids. One-parameter optimal flux reconstruction schemes are obtained by minimizing the error associa...

This paper presents a novel strategy that exploits the properties presented by the nonlinear model of direct current motors, to obtain simultaneously the required control voltages in the armature and in the field windings when velocity and magnetic flux are considered as reference inputs. In this scheme, it is considered that the current signals for both windings are available, as well as the signal of the angular position. So by means of a second order filter, the signal that takes the place of the angular velocity is obtained. By using the Lyapunov stability theory, stability of the closed loop system, global convergence of angular velocity and field flux is concluded, moreover all the states variables are bounded for all initial conditions. Experimental tests confirm the theoretical proposal; that is, global asymptotic tracking of the angular velocity and field flux is ensured. The equations of this proposal are physically implementable and due to the structure of the control scheme, the voltages of both windings can be tuned in such a way that less current dissipates, resulting in energy saving and having the same response of velocity.

In this paper, the suppression mechanism of torque ripple for the flux-switching permanent magnet (FSPM) motor is investigated. According to the flux modulation principle, the generation principle of torque harmonics is analyzed, which is generated by the interaction between the radial and tangential airgap harmonics. Based on the analysis, a method to suppress the torque ripple of the FSPM motor is proposed, where the airgap harmonics are newly applied to be the bridge to establish the relationship among torque ripple, torque harmonic components, and key design parameters. To confirm the effectiveness of the proposed method, a FSPM motor with the V-shape permanent magnet (VS-FSPM) motor is selected as the research example. The leading torque harmonics and leading airgap harmonics of the VS-FSPM motor are picked out effectively. Some key design parameters are selected according to the flux modulation principle to improve the leading airgap harmonics and reduce the corresponding torque ripple successively. Furthermore, the torque ripples of the initial and improved VS-FSPM motor are calculated and compared in detail. Finally, a prototype motor is built and tested. Both the theoretical analysis and experimental results verify the effectiveness of the proposed new method.

Accurate parameters are critical to permanent magnet synchronous machine (PMSM) drive. This paper investigates accurate flux linkages, inductances and PM flux linkage estimation for PMSM with core loss compensation. With conventional model, core loss will induce the flux linkage error especially in the deep saturation region. Hence, this paper firstly proposes a novel differential modeling technique to compensate core loss, in which differential measurement is defined as the incremental value calculated from the actual measurements under two different speed conditions. With multiple differential measurements, the flux linkage error due to core loss can be compensated to improve the accuracy of flux linkage estimation. Then, the polynomial based flux linkage model is employed to derive the PM flux linkage and cross-saturation inductances. Self-inductances are estimated from the flux linkage model using least squares method. The proposed approach can accurately estimate parameters without the need of core loss data and can improve the estimation accuracy especially in deep saturation region, which is validated on a laboratory interior PMSM and compared with existing methods under various operating conditions.

An experimental study has been conducted to investigate the heat transfer characteristics of supercritical carbon dioxide (sCO2) uniformly heated in the horizontal circular smooth tube. The results illustrated that there was a significant difference in heat transfer between the top wall and bottom wall due to the buoyancy. Bulk flow acceleration cannot be negligible in the high heat flux region, which leads to heat transfer deterioration. A new heat transfer correlation is proposed, in which the buoyancy parameter and bulk flow acceleration have been taken into account. The new correlation and six classic correlations for sCO2 are examined in horizontal tubes. The comparison indicates that the new correlation has a better performance for sCO2 flowing through a horizontal heating tube under natural circulation conditions. For example, 94.9% of the calculated results using the new heat transfer correlation were within ±30% of the experimental results while only 87.9% of that using the Jackson correlation (the best of the six) were within the same error bands.

In this research the membranes distillation was used to remove calcium ions from heavy sewers at dairy plants in Iraq. This method is easy to operate, easy to manage and has many economic benefits. A chemical treatment was carried out on it using alum as a coagulant, different tests achieved samples before and after passing MD, according to APHA, AWWA, WEF. The results showed that obtained in water treatment trust that has been manufactured and edited according to the characteristics of the water waste the interests of the dairy capacity of this method to remove the calcium ion to a certain extent it is when the concentration reaches the inside of this ion to 1428.57 mg per liter, where to start the composition of hydroxides of calcium responsible for pain. The optimal working temperature ranges from 20-22 ° C and the flow is around 0.66 kg.m-2.h-1, here was the result of a layer of plaster that led to clogged membrane and folding and was stopped for washing and cleaning.

This work investigates the effect of design parameters of permanent magnet (PM) and flux barriers (FBs) in the rotor on the anti-demagnetization ability (ADA) of fractional slot concentrated windings interior permanent magnet (IPM) motors for electric scooters. A 2.5 kW IPM motor (12 slots and 8 poles) is designed for a wide speed range, and its ADA associated with different PM and FB arrangements is studied under high temperature and high current density operations. The analysis shows the relationship between the ADA and characteristic current (Ich, defined as the ratio of PM flux linkage to d-axis inductance). It is also found that proper designs of flux barriers can significantly improve the ADA of the IPM motor without much affecting Ich. Thus, the motor ADA and performance can be simultaneously improved. Finite element analysis is used for evaluation, and experiments are conducted to validate the analysis.

High-speed position-sensorless control of switched reluctance motor (SRM) drives is often realized by searching a priori flux linkage lookup table. However, obtaining the nonlinear flux linkage characteristic requires time-consuming offline measurement and occupies large memory storage. To deal with this problem, this article proposes a new position estimation scheme for SRM drives without using any magnetic characteristics. This feature is achieved by using a quadrature flux estimator (QFE) that can extract the fundamental flux and its quadrature signal from the real-time calculated flux linkage. The flux bias and flux harmonics can also be suppressed by the QFE’s adaptive bandpass capability. Therefore, the proposed method can reduce the nonlinearity in SRM flux linkage and derive simple sine-cos position signals. Afterward, the rotor position and speed can be estimated from the orthogonal flux signals using a three-phase phase-locked loop. To baseline the advantages, comparative experimental validation with the conventional method is conducted on a three-phase 12/8 SRM test bench. The results show that the proposed scheme can achieve the same estimation accuracy as the conventional method even though no magnetic characteristics are used.

In this paper, the balanced bidirectional-magnetization effect of a newly developed hybrid-magnet-circuit variable flux memory machine (HMC-VFMM) is revealed and investigated. Firstly, the machine topology and variable flux principle of the HMC-VFMM are described, respectively. In addition, the balanced bidirectional-magnetization effect is analytically unveiled by using a Fourier-series based hysteresis model of low coercive force (LCF) magnet. The PM magnetization characteristics are then investigated by a coupled solution, which is employed to identify the mismatch between the LCF magnet movement trajectories subject to either continuous one-way or bidirectional alternate current pulses. Finally, a prototype is manufactured and tested to verify the theoretical analyses.

This article presents a novel high temperature heat flux (HTHF) sensor based on micromachined thermocouple (MTC) to meet the needs of transient high heat flux detection in ultrahigh temperature environments, such as fire research, high-power pulsed lasers testing, and aerospace engineering. The targeted design, fabrication, and package of an MTC-based HTHF sensor with excellent heat dissipation capacity are proposed, and relevant experiments were conducted in two aspects. First, powerful laser tube-based tests at ambient temperature show that such a sensor can detect a heat flux high to 10.8 MW/m2 with an extremely fast response; its response time, in this case, is 1.9 ms. And then, turbine engine test pipe based tests at high temperature reveal that the sensor with water cooling could survive at 1200 °C for at least 100 s. Compared to conventional heat flux sensors, it is more sensitive to transient heat flux changes and has a faster response speed. Such satisfactory performance makes the sensor extremely competitive in ultrahigh heat flux detection in extremely harsh environments.

In this paper, a flux-controllable permanent magnet (FC-PM) motor has been designed and optimized to achieve the optimal torque component distribution under different flux leakage conditions. The FC-PM motor can realize the flexible adjustment and control of air-gap magnetic field by reasonable flux bridge design, which further broadens the speed range of the motor effectively. The focus of the research is to analyze and optimize the torque characteristics in combination with typical operation conditions. Firstly, a motor topology is proposed, the mechanism of flux leakage and the distribution of torque characteristics are studied. Then, according to different flux leakage operation conditions, an optimization method considering the torque component distribution is newly proposed. Based on the proposed optimization method, the optimal motor can be obtained. Finally, the performance of the optimal motor is analyzed and compared with the initial motor. The comparison results indicate that, based on the proposed optimization method, the torque output capability is improved effectively while the desired leakage flux adjustment range is maintained.

In this paper, based on a 6-stator-coil/17-rotor-tooth (6/17) conventional concentrated-winding multi-tooth flux-switching permanent magnet (C-MFSPM) machine, a novel full-pitch multi-tooth FSPM (FP-MFSPM) machine is proposed by changing winding configurations. Then, the electromagnetic performance of six FP-MFSPM topologies sharing the same 6-stator-coil but with different rotor teeth combinations, namely 6/13, 6/15, 6/17, 6/19, 6/21, and 6/23, is compared by using finite element analysis (FEA). The results show that 6/17 and 6/19 are the optimal stator-coil/rotor-tooth combinations for FP-MFSPM machines, which exhibit better electromagnetic performance, such as more enormous torque and smaller torque ripple. Thereafter, the existing C-MFSPM and the proposed FP-MFSPM machines with 6/17 and 6/19 structures are quantitatively compared in terms of no-load back electro-motive force (back-EMF), air-gap flux density, cogging torque, electromagnetic torque, torque ripple, etc. The FEA-predicted results validate that the proposed FP-MFSPM machines have more sinusoidal back EMF, larger torque output, and smaller torque ripple, which are superior to the C-MFSPM topologies.

Energetic particle precipitation associated with pulsating aurora (PsA) can reach down to lower mesospheric altitudes and deplete ozone. It is well documented that pulsating aurora is a common phenomenon during substorm recovery phases. This indicates that using magnetic indices to model the chemistry induced by PsA electrons could underestimate the energy deposition in the atmosphere. Integrating satellite measurements of precipitating electrons in models is considered to be an alternative way to account for such an underestimation. One way to do this is to test and validate the existing ion chemistry models using integrated measurements from satellite and ground-based observations. By using satellite measurements, an average or typical spectrum of PsA electrons can be constructed and used as an input in models to study the effects of the energetic electrons in the atmosphere. In this study, we compare electron densities from the EISCAT (European Incoherent Scatter scientific radar system) radars with auroral ion chemistry and the energetics model by using pulsating aurora spectra derived from the Polar Operational Environmental Satellite (POES) as an energy input for the model. We found a good agreement between the model and EISCAT electron densities in the region dominated by patchy pulsating aurora. However, the magnitude of the observed electron densities suggests a significant difference in the flux of precipitating electrons for different pulsating aurora types (structures) observed.

Solar eclipses provide an excellent opportunity to study the effects of a sudden localized change in photoionization flux in the Earth's ionosphere and its consequent repercussion in the Geomagnetic field. We have focused on a subset of the data available from the North American 2017 eclipse in order to study VTEC measurements from GNSS data and geomagnetic field estimations from INTERMAGNET observatories near the eclipse path. Our simultaneous analysis of both datasets allowed us to quantify the ionosphere and magnetic field reaction to the eclipse event with which allowed us to compare how differently these take place in time. We found that studying the behaviour of VTEC differences with respect to reference values provides better insight of the actual eclipse effect and were able to characterize the dependence of parameters such as time delay of maximum depletion and recovery phase. We were also able to test models that link the ionospheric variations in a quantitative manner. Total electron content depletion measured from GNSS were fed into an approximation of Ashour-Chapman model at the locations of geomagnetic observatories and its predictions match the behaviour of magnetic field components in time and magnitude strikingly accurately., Comment: Accepted for publication in Advances in Space Research