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The interturn short-circuit is one of the most often failures of electric motors which can lead to serious consequences with the irreversible damage of the whole drive. The detection of these short-circuits is a challenging task depending also on the parameters of the winding of the analyzed machine. The equivalent circuit parameters are minimally affected if the winding consists of a high number of parallel wires, and only a single turn of one parallel wire is short-circuited. The measurement of additional Joule losses are then expected to be the most proper approach; the special rotor and testing stand for this purpose is designed in this paper to ensure easy manipulation with the measured stators.

Water and energy are so versatile that play great role in fulfilling the daily requirements of human life. Having knowledge on the future water and energy demand of the world, country, region and even a single city/town helps for planning and establishing water and energy policies. A regression model was used to estimate the energy and water demand considering the socio-economic drivers as parameters. An average population growth rate of 5.2% and a GDP growth rate of 11% were used as base scenarios to predict the residential, commercial and industrial energy demands. Population and GDP per capita based scenario was used to predict the transport (street-lighting) energy demand. The total energy demand for residential, commercial, industrial sectors and street-lighting was around 50 and 190 Peta Joule in 2030 and 2050 respectively. Additional, the energy requirement for water distribution, transmission, and water treatment was determined. Similarly, this scenario was used to determine residential, commercial and industrial water demand. The total water demand was predicted to be 0.4 and 0.68 billion cubic meters in 2030 and 2050 respectively.

Transparent soft actuators have been receiving enormous attention due to their potential for application in camouflage robotics, accurate monitoring/controlling of soft robots, etc. Herein, we report an electrically powered soft actuator relying on reversible nematic-to-isotropic transitions of liquid crystalline elastomers (LCEs) induced by Joule heating with silver nanowires (AgNWs). Taking advantage of the high conductivity and transparency of the AgNWs electro-heater, the assembled soft actuator can attain high transmittance (60-70%) in the visible region. It exhibits a large bending deformation upon the application of a low voltage of 6 V within 20 s, and returns to its original state when withdrawing the voltage. In addition, the degree of bending can be controlled by the voltage applied and application time of the electric field. The LCE-based transparent soft actuators with low voltage switching are particularly promising for application in smart soft robots with optical components. Agency for Science, Technology and Research (A*STAR) This work was supported by the Science and Engineering Research Council of the Agency for Science, Technology and Research (A*STAR), Singapore, under the Industry Alignment Fund – Pre-positioning Programme (IAF-PP) (Grant No. A1786a0034).

This study presents full transient, three-dimensional numerical models of a PV–TEG hybrid module coupled with single-phase inverter by co-simulation. The influence of factors, such as wind speed, solar radiation intensity, or ambient temperature on the PV–TEG system, was also examined. The numerical model was implemented using Ansys software which accounted the phenomena of Thomson, Seebeck, and Joule’s heat place on the TEG system. Furthermore, its impact on total electrical efficiency was studied. The heat transfer surface of the passive heat sink and forced air circulation positively affected the total heat transfer, and therefore helped to maintain the electrical efficiency at a higher level. Simulation of the single-phase inverter with a PV–TEG system allows the determination of the power characteristics of the system in real time. The results of the study presented may provide a basis for performance optimization of a practical PV–TEG-inverter hybrid system co-design.

A 1.04 J, λ=515 nm laser at 1 kHz repetition rate was demonstrated by frequency doubling 1.2 J, temporally shaped square 2 ns pulses from a cryogenically cooled Yb:YAG laser in LBO crystals.

This article discusses the storage of grid energy using Brayton engines to convert energy reversibly to heat and storing the heat in molten nitrate salt. The physics is similar to that of compressed air energy storage, except that all the energy is stored as heat instead of just part of it, and the compression-expansion cycle is executed twice, thus eliminating the need for an underground cavern. The upper temperature, similar to the present-day supercritical steam plants (and thus within steel creep limits), gives an asymptotic round-trip efficiency of about 70% with present-day turbomachinery. Like pumped hydroelectric storage and flow batteries, the Brayton battery separates the engine from storage medium, allowing the cost per engine watt to be priced separately from the cost per stored joule. The cost per engine watt is somewhere between its value for a present-day gas turbine and half this value. The low cost comes from being a closed-cycle gas turbine similar to a supercritical CO2 engine, with a power proportional to the background pressure in the loop. The cost per stored joule, functionally the cost of the salt, is so low that it is irrelevant for storage times less than 24 h. The Brayton battery has no potential explosion danger, no land-use issues, no environmental issues from low-pH fluids and metal ions, and no semiconductors.

This paper presents a current shaping method for torque ripple and mean air-gap radial forceshape harmonics reduction, under minimum Joule losses, used for air-born and structure-born vibration reduction in 3-phase PMSM electric drives. The main source for structure-born noise in electric powertrains is the torque ripple, while the main source for air-born noise are the radial air-gap forces. The proposed method uses a Fourier-decomposed LUT model obtained from updating the 2D electromagnetic FE model using test-bench results. Modal testing is used to update the structural model, and the vibration response on the machine full RPM range is determined using the vibration-synthesis method. The proposed current shaping algorithm is deterministic and can be used on any topology of 3-phase PMSMs. The torque and mean air-gap force harmonics that are intended for reduction can be arbitrary selected and their minimization can be fully completed if the maximum current and voltage constraint are respected. On the machine under test, vibration reduction is accomplished, especially for the mechanical orders that interact with the second mode-shape., SCOPUS: ar.j, info:eu-repo/semantics/published

After 60 years of development efforts since the 1960s to the current Giga-/Tera-Scale-Integration or System-on-a-Chip era [1]–[3], it is expected that Monolithic Silicon IC products using 2-nm CMOS devices will appear soon. The subsequent challenge is whether more novel device structures using heterogeneous materials and 3D-structures will be invented to realize manufacturable 1-nm ICs. On the other hand, through 20 years of efforts since 1999, many Heterogeneous Integration (HI) [4]–[6] products, each of which is composed of silicon and non-silicon materials/ dice/chiplets, diversified devices/circuits, innovative architectures and multi-dimensional arrangements of dice and other components inside either Chip-package or Module, have been increasingly emerging, especially recently benefiting from a strong driving force stimulated by the IEEE HI Roadmap unveiled in 2018 [5]. This paper presents an exciting, powerful and new Trend of Semiconductors, Intelligent Grand Scale Integration (IGSI), which is optimally utilizing Mixed Integration of Monolithic and HI Technologies (Si-4.0 [6]) with embedded 3A's (Algorithm, Architecture and AI) Design-Intelligences. A key target of IGSI technologies is to drive much higher energy efficiency of managing electronic information for more-effective/ intelligent future systems with better performance, lower power, higher reliability and smaller form-factor than those of our current systems. One effective way as proposed is to network multiple Self-Smart MicroSystems (S-SmS) each of which is designed with 3A's to a complete system level which can handle huge data processing smartly in its own compact multi-dimensional form factor like in a versatile solid-state micro-universe which has abundant self-contained intelligent functions with maximized speed-power efficiency due to close proximity of electronic/photonic/ micro-mechanical operations. It is projected that in such an S-SmS each Joule (energy unit) be able to operate more than 10^20 devices per die per joule allowed by thermodynamics (on the other hand, its performance can reach over hundreds of thousands of TOPS - Tera Operations Per Second) inside and/or across these MicroSystems to complete the final system need. Then how powerful a future system can be by networking enough S-SmS units and furthermore how many unprecedented and unexpected applications will be unleashed! To use AI computing systems as an example, it is expected that S-SmS be quickly applied to AI's edge, device or wearable applications. Moreover, just like the experiences of migrating from a Mainframe computer to networked PC Servers, Data servers used in AI Clouds may use such a networked S-SmS architecture to build large systems in order to optimize the energy efficiency and heat dissipation. The trend equally adds values to system's transformation and optimization in Autonomous Car areas, Industrial 4.0 Factory areas, Telecommunication and Computing areas and so forth.

Transition Edge Sensor (TES) is a key component for Hot Universe Baryon Survey (HUBS), which is proposed in China to address the so-called “missing baryon problem”. A stable heat sink below 100 mK is needed for the detector’s noise suppression and high resolution. Since HUBS is a satellite based observation mission, a complicated cooling system suitable for space application becomes an important supporting sub-system. A compounded cooling system, including a mechanical cryocooler and an adiabatic magnetization refrigerator (ADR), has been proposed for HUBS. The mechanical cryocooler is used as the pre-cooling 4 K stage, and the ADR is responsible for further reducing the temperature to below 100 mK. High-frequency pulse tube cryocooler (HPTC) and HPTC combined with Joule Thompson cooler (J-T) are two candidates for the mechanical pre-cooling stage, both of which are currently under development. The ADR is being designed and processed. In this paper, we will present the preliminary architecture of the HUBS cooling system, as well as the latest states of HPTC, J-T, and ADR.

The emergence of multifunctional cement-based materials in the construction industry has the potential to shift the paradigm from strength-only performance to new functionalities enabled by electron conducting capabilities in one of the most material- and energy-intensive industry sectors worldwide. To enable such developments, we present results of a hybrid experimental-theoretical investigation of the electrical conductivity and resistive (Joule) heating of highly heterogeneous nanocarbon (nCB)--cement-based composites (pastes and mortars). By analogy with diffusivity, we find that electrical conductivity is determined by the electric tortuosity of a ``volumetric wiring'' permeating a highly heterogeneous matrix from percolation to saturation. From a combination of electrical conductivity and Joule heat rate measurements, we show that the electric energy dissipation at the origin of the Joule heating originates from spatial electric-field fluctuations, reminiscent of the fluctuation-dissipation theorem. We report that these fluctuations---in first order---are well captured by functional relations of the electric tortuosity of the composite material, and synthesize these observations into a first-order dissipation-tortuosity model. We suggest that harvesting the benefits of electron conducting cement-based materials, such as resistive heating, electromagnetic shielding, and energy storage, will ultimately focus on settling the competition between conductor concentration and electric tortuosity. Given the global environmental footprint of concrete, the results open venues for the sustainable development of concrete for existing and emerging green technology applications.

Thermal treatment may reverse the osseointegration of implants and could become an atraumatic controlled method for implant removal in the future. The aim of this nonrandom in vitro study was to empirically identify suitable sources for a controlled heating process, to generate a homogenous temperature distribution at a threshold level of 47°C for future in vivo research. Two different setups evaluating 4 different sources (water, laser, monopolar, and an electrical joule heater device) were used to carry out infrared measurements and numerical calculations at 47°C along the implant axis and along the peri-implant area at the axial plane. Furthermore, required time intervals to heat up the implant tip from 33°C to 47°C were determined. The monopolar electric device led to the most uneven and unpredictable implant heating and was therefore excluded. The thermal analysis suggested identical thermal distributions without any significant differences for water and electrical joule sources with a heat maximum at the implant shoulder (P > .05). On the other hand, the laser device may produce the temperature maximum in the middle of the implant without any afterglow effect (P < .01). When the implant was heated from 33°C to 47°C, the water device indicated the fastest approach. Thermal distributions of water and laser sources may be suitable for clinical applications. For future research, numerical analysis suggests an ideal time interval of 120 seconds to 180 seconds for a homogenous implant temperature of 47°C.

A conventional field oriented control (FOC) relies on park transform and sinusoidal back EMF, in order to tread harmonic signals as constants. As a consequence, resulting control structure based on linear PI controllers is very simple and well tested. However if the back EMF of the machine is not sinusoidal, single coordinated dq system fails to adequately describe the motor, which negatively impacts the control performance and causes additional torque ripple and joule losses in the motor. A commonly used methods for compensation of negative effects of non-sinusoidal back EMF significantly increase the complexity of the algorithm. In this paper we use popular version of predictive control called FCS-MPC which does not relies on the park transform, and thus it allows to address this issue in a simple way. The algorithm has been tested in simulations using the real data of target permanent magnet synchronous motor (PMSM) drive of rated power 100kW.

We review the motivation, goals, and achievements of the Photonic Integrated Networked Energy efficient datacenter (PINE) project, which is part of the Advanced Research Projects Agency–Energy (ARPA-E) ENergy-efficient Light-wave Integrated Technology Enabling Networks that Enhance Dataprocessing (ENLITENED) program. The PINE program leverages the unique features of photonic technologies to enable alternative mega-datacenters and high-performance computing (HPC) system architectures that deliver more substantial energy efficiency improvements than can be achieved through link energy efficiency alone. In phase 1 of the program, the PINE system architecture demonstrated an average factor of 2.2 × improvement in transactions/joule across a diverse set of HPC and datacenter applications. In phase 2, PINE will demonstrate an aggressive 1.0 pJ/bit total link budget with high-bandwidth-density dense wavelength-division multiplexing (DWDM) links to enable additional 2.5 × or more efficiency gains through deep resource disaggregation.

We report on a Joule-level flashlamp-pumped 1047 nm Nd:YLF laser with near-diffraction-limited beam quality. The laser was based on master oscillator power amplifier design. The output pulse energy was 2 J with 3 ns pulse duration at 10 Hz pulse repetition rate. High beam quality of the laser output was provided by using an SBS mirror and astigmatism correction in the amplifier.

This chapter focused on the issue of radio resource allocation in overlay CR systems, where the primary system employs physical -layer security techniques. Unlike most previous contributions that focus on traditional and non -EE performance metrics such as achievable rates, this chapter has described a radio resource allocation framework to optimize both the energy efficiency of a cognitive communication system while keeping the confidentiality of the primary system. To this end, a key step has been the introduction of the performance metric of EE, defined as the ratio between the system capacity (or achievable rate) and the consumed power, including both radiated and hardware power. This metric measures the amount of information that can be reliably transmitted per Joule of consumed energy, thus being a natural measure of the energy efficiency of the communication. Both the ability of cognition and EE are anticipated to be particularly relevant in future communication networks, which will be composed of an unprecedented amount of devices.

Five-phase machines (FPIM) have recently gained notable interest in wind energy generation systems thanks to their additional degrees of freedom that keep the machine run steadily under fault conditions. In the available literature, postfault operation of multiphase machines is preferably implemented using two techniques: minimal losses (ML) or maximum torque per ampere (MT) techniques. In the ML scenario, the optimization problem aims at minimizing the stator Joule losses. This paper revisits a five-phase induction motor's postfault operation of under a single open phase fault with optimizing the stator loss machine optimal currents calculation over the full loading range. The proposed algorithm, which combines the advantage of both MT and ML techniques, attempts to minimize the five phase machine stator losses induced by the current components of both the fundamental aft and the secondary xy subspaces. A detailed simulation study to a 1.5kW five-phase induction machine based on MATLAB has been conducted to validate the proposed optimal controller.

We present the principle and implementation of a new type of fast response evaporative calorimeter designed to work at cryogenic temperatures and above-ambient pressures. It is capable of measuring input energy from an electric pulse and the thermal output energy by measuring the evaporation of liquid nitrogen through a mass flow meter. This system may be used to measure either the steady heat output from the system submersed under the cryogen or the heat output that results from a fast square-wave profile electrical pulse of duration from 10 µs or longer. The energy output of metal capillary-wire composite systems has been measured calorimetrically. A four-wire measurement was used to monitor the input electric energy with an uncertainty less than 5% for a typical pulse. Mass flow meters and pressure regulation systems were used to monitor the rate of evaporation of liquid nitrogen with a typical precision of 2 std.-ml/min. For a typical pulse, the integrated mass flow of nitrogen could be determined with an uncertainty less than 3%. The pressure controllers and ballast compliance volumes allow the system to return to a steady state of mass flow in less than 2 min following an electric pulse. The system is capable of housing and measuring four separate wire-capillary systems in a single Dewar. On average, a calibration resulted in 3.9 std. ml evaporated per joule of input energy. This corresponds to a 97% efficiency for this calorimeter.

The multiphysics simulation methodology presented in this paper permits extension of computational fluid dynamics (CFD) simulations to account for electric power generation and its effect on the energy transport, the Seebeck voltage, the electrical currents in thermoelectric systems. The energy transport through Fourier, Peltier, Thomson and Joule mechanisms as a function of temperature and electrical current, and the electrical connection between thermoelectric modules, is modeled using subgrid CFD models which make the approach computational efficient and generic. This also provides a solution to the scale separation problem that arise in CFD analysis of thermoelectric heat exchangers and allows the thermoelectric models to be fully coupled with the energy transport in the CFD analysis. Model validation includes measurement of the relevant fluid dynamic properties (pressure and temperature distribution) and electric properties (current and voltage) for a turbulent flow inside a thermoelectric heat exchanger designed for automotive applications. Predictions of pressure and temperature drop in the system are accurate and the error in predicted current and voltage is less than 1.5% at all exhaust gas flow rates and temperatures studied which is considered very good. Simulation results confirm high computational efficiency and stable simulations with low increase in computational time compared to standard CFD heat-transfer simulations. Analysis of the results also reveals that even at the lowest heat transfer rate studied it is required to use a full two way coupling in the energy transport to accurately predict the electric power generation.

This paper analyzes the magnetization effect in the weighing phase and moving phase of joule balance with compensation coil. The additional errors introduced in the two measurement phases can be cancelled out theoretically and the experimental phenomenon also match well with the analysis.

In 2017, we have published a measurement result obtained with the NIM-2 joule balance and the relative standard uncertainty is $2.4\times 10^{-7}$ . Since then, a series of approaches have been carried out to decrease the main uncertainty contributions. A new permanent magnet has been constructed to get higher magnetic field. A magnetic shielding and compensation coils were used to decrease the effect from the environment. The alignment was improved by a parasitic displacements measurement system and the using of a new suspension system. By Sept. of 2019, the type-A uncertainty of NIM-2 has been reduced to $3\times 10^{-8}$ . In Oct. 2019, the NIM-2 joule balance participated in the key comparison (CCM.M-K8 2019).

A preliminary study suggests that the one-mode one measurement phase (OMOP) scheme may be feasible in the joule balance because of its quasi-static measurement feature. Combined with the recent research conclusion on the magnetization effect in the joule balance with compensation coil, two necessary hardware improvements to enable the OMOP joule balance are analyzed in this paper. Furthermore, a key parameter that can affect the statistical uncertainty of the final mass measurement result is experimentally determined.

This paper presents the control of a Switched Reluctance Generator (SRG) for low voltage DC grid with the objective of efficiency maximizing. Analysis of the energy conversion, including electrical machine losses (Joule, magnetic, mechanical) and power converter losses (switching and conduction), has shown that there is an optimal combination of control variables (turn-on and conduction angles, phase current reference), which maximizes the drive efficiency. The control variables are derived from a Finite Element Analysis and parametric optimization algorithm for all of the operating points in the torque-speed plane and stored in lookup tables. The performances are evaluated with intensive numerical simulations and experimental tests with a 8/6 SRG feeding a DC resistive load for different rotational speeds. The results show good performances of the output DC voltage control with low ripples, even in the presence of speed and load variations. Thanks to the optimization, simulation results show that beyond 1500 rpm, drive efficiency is higher than 60 % and almost reaches 70 % at nominal speed. The experimental results show that, for light loads and beyond rated speed, the drive efficiency lies in the range between 60 % and 80 % .

Many industry applications required the use of the induction motors. In such envirenement the electrical machines are facing of many stressed operating conditions. One of the critical creteria which decide the choice of the induction motor is the thermal behaviour under different mode operation. In this paper a study of the thermal behavior of an induction motor is presented. In order to predict the temperature in the different machine components, a model based on the lumped parameter thermal network has been developed. The geometry of the machine and the thermal properties of its various components are used to express the developed model. The joule and the iron losses are considering as the inputs. The proposed model is implemented and tested using MATLAB software. It is a simple model which could predict rapidly the different temperatures. Keywords: Induction motor, Thermal analysis, Lumped parameters thermal network, Modeling, Heat sources

The object of investigation in the present work are the thermal effects that occur in plant materials during the pulsed electric field treatment for assisting the process of extraction of specific oils. The aim of the study is to analyze the influence that the properties of the solution in which the material is being processed have on the thermal field configuration in the studied cell tissue. The distribution of the electric field, the currents and corresponding Joule losses, the temperatures and the temperature gradients are determined and compared for several solvents with different conductivity. The analysis of the coupled electric and thermal processes is carried out on the basis of fields modeling using the finite element method. Regions of special attention are the areas of neighborhood between two cells where the processes are modeled in two steps: before and after electroporation on the basis of corresponding changes in the size and conducting properties of the contact zone.

International audience; Control of filament growth within conductive bridge random access memories (CBRAM) is of crucial interest in order to ensure the reliability of such emerging devices. Here, we demonstrate that scanning joule expansion microscopy (SJEM) can be used to detect and precisely localize conductive filaments within operating crossbar CBRAM devices. Flexible memory devices based on Pd/Al2O3/Ag stacks are first elaborated at low temperature on polyimide substrate. These devices show set and reset operations at low voltage (

Laser-driven positron production is expected to provide a non-radioactive, controllable, radiation tunable positron source in laboratories. We propose a novel approach of positron production by using a femto-second laser irradiating a microstructured surface target combined with a high-Z converter. By numerical simulations, it is shown that both the temperature and the maximum kinetic energy of electrons can be greatly enhanced by using a microstructured surface target instead of a planar target. When these energetic electrons shoot into a high Z converter, copious positrons are produced via Bethe-Heitler mechanism. With a laser (wavelength λ = 1 μm) with duration ~36 fs, intensity ~5.5 × 1020 W/cm2 and energy ~6 Joule, ~109 positrons can be obtained.

In this paper, a novel method to generate optical frequency combs (OFCs) using nanoscale structures is explored. The growing demand for on-chip photonic processing dictates the need for multi-wavelength light sources, such as OFCs, that can be densely integrated with low processing power. Photonic crystal structues provide a viable method to generate all-optical modulation with sub-femto joule switching power and high density integration potential. This method of all-optical modulation is utilised here to generate an OFC from photonic crystal nanocavities and waveguides. Very- at-topped optical frequency combs with a small intensity variation can be generated based on theoretical predictions via detailed analysis of coupled mode theory for photonic crystal nanocavities and waveguides.

SPIE Conference on EUV and E-ray Optics, SPIE LASE, Prague, Czech republic, 3 Apr 2019 - 4 Apr 2019; Proceedings of SPIE 11270, 1127002 (2019). doi:10.1117/12.2563450, The generation and use of THz radiation for electron acceleration and manipulation of electron bunches has progressed over the last decade to a level where practical devices for THz guns, acceleration and a wide range of beam manipulations have become possible. Here, we present our progress on generation of single-cycle THz pulses at the two-hundred micro- Joule level to drive advanced acceleration and beam manipulation devices. Specifically, we use pulses centered at 0.3 THz to power a segmented terahertz electron accelerator and manipulator (STEAM) capable of performing multiple high-field operations on the 6D-phase-space of ultrashort electron bunches. Using this STEAM device, we demonstrate record THzacceleration of >60 keV, streaking with 2 kT/m strength, compression to ~100 fs as well as real-time switching between these modes of operation. The STEAM device demonstrates the feasibility of THz-based electron accelerators, manipulators and diagnostic tools enabling science beyond current resolution frontiers with transformative impact., Published by SPIE, Bellingham, Wash.

In this paper, an analysis procedure for the induction motor rotor losses evaluation is presented. The technique uses only magneto-static and linear time-harmonic simulations, avoiding the time-domain approach. The rotor losses, analyzed in this paper, are due to stator slot harmonics. This kind of losses take place in both the rotor iron and, as Joule losses, in the cage. The iron losses are due to high frequency flux pulsation, thus they can be serious and not negligible, specially during high speed and frequency operation. A fast analysis technique is implemented to evaluate the rotor losses, due to the stator space harmonics,. avoiding the long time-domain approach. The analysis is done carefully taking into consideration the saturation effect and the different rotor cage reaction, in presence or not of the rotor skewing, is considered too.

To date, research on heat pumps (HP) has mainly focused on vapour compression heat pumps (VCHP), transcritical heat pumps (TCHP), absorption heat pumps, and their heat integration with processes. Few studies have considered the Joule cycle heat pump (JCHP), which raises several questions. What are the characteristics and specifics of these different heat pumps? How are they different when they integrate with the processes? For different processes, which heat pump is more appropriate? To address these questions, the performance and integration of different types of heat pumps with various processes have been studied through Pinch Methodology. The results show that different heat pumps have their own optimal application range. The new JCHP is suitable for processes in which the temperature changes of source and sink are both massive. The VCHP is more suitable for the source and sink temperatures, which are near-constant. The TCHP is more suitable for sources with small temperature changes and sinks with large temperature changes. This study develops an approach that provides guidance for the selection of heat pumps by applying Process Integration to various combinations of heat pump types and processes. It is shown that the correct choice of heat pump type for each application is of utmost importance, as the Coefficient of Performance can be improved by up to an order of magnitude. By recovering and upgrading process waste heat, heat pumps can save 15–78% of the hot utility depending on the specific process.

International audience; In this paper, we propose a combined finite volume-finite element scheme, for the resolution of a specific low-Mach model expressed in the velocity, pressure and temperature variables. The dynamic viscosity of the fluid is given by an explicit function of the temperature, leading to the presence of a so-called Joule term in the mass conservation equation. First, we prove a discrete maximum principle for the temperature. Second, the numerical fluxes defined for the finite volume computation of the temperature are efficiently derived from the discrete finite element velocity field obtained by the resolution of the momentum equation. Several numerical tests are presented to illustrate our theoretical results and to underline the efficiency of the scheme in term of convergence rates.

Summary In the process of oil production, the pressure in the well and reservoir can be reduced below the pressure of oil saturation with gas, in this case, oil degassing can occur both in the reservoir and the well, and only in the well. The study of mathematical models of the temperature field taking into account the Joule – Thomson effect and the adiabatic effect in the filtration of oil, water and carbonated oil in the reservoir is devoted to the work (Chekalyuk E. B., 1965; Hasan A. R. et al., 1988; Valiullin R. A. et al., 1994; Sharafutdinov R. F. et al., 2017). It is shown that the decisive contribution to the formation of a temperature anomaly at the outlet of the formation is provided by the heat of the phase transition during oil degassing. The paper discusses the features of the formation of the temperature field in the wellbore for a multi-layer system, taking into account the degassing of oil on the basis of mathematical modeling of thermohydrodynamic processes.

Multi-three-phase drives are a particular case of multiphase systems, which are often used in high-power applications, such as wind-energy generation, naval propulsion, and railway propulsion. In a multi-three-phase system, the electric machine is fed by more than one three-phase converters. A current-sharing algorithm for multi-three-phase drives allows setting unequal current references among the converters so that each of them differently contributes to the generation of the magnetic torque and flux. Suitable current-sharing control systems already exist and have been presented for multi-three-phase machines. In this article, we illustrate a current-sharing technique where the contributions to the rotor flux for the three-phase inverters, related to the d -axis current, are decoupled from the contributions to the electromagnetic torque, which depends on the q -axis current. Also, the presented algorithm minimizes the joule losses in the stator winding. Finally, the advantages of the proposed method are analyzed and confirmed by experimental tests. The effectiveness of the control strategy is validated on a scaled prototype of a quadruple three-phase starter/generator for More-Electric-Aircraft applications.

The revised SI is the system of units in which the standards of units dependent on physical constants and quantum effects. The redefinition of the SI system on the base of physical constants is its great advantage. However, the revised SI system is understood rather by narrow community of scientists and experts of metrology, not by a wide population of users. In particular this remark relates to the definitions of the kilogram and the kelvin in the REVISED SI. Critical remarks on the new SI concern sophisticated definitions, the set of base units and high costs of implementation the definition of the kilogram. The definitions only repeat the values of physical constants. New standards of the kilogram (watt balance or XRCD method) are at least 30–50 times more expensive than the “old” standard – the artefact of PtIr alloy. In result, only about 10 national metrology institutes in the world are able to install and operate new standards of the kilogram. Before and after adopting the revised SI there are the proposals to replace the ampere, the base unit, by the wolt (or the ohm), the kelvin by the joule, and the unit of mole by a new unit of amount of substance (Leonard‘s proposal). In the paper the experimental set-up of the standard of mass based on the watt balance is presented.

This work deals with an analytical approach aimed at accurately predicting Joule losses in innovative hairpin winding layouts. While hairpin windings are seeing an everincreasing use in automotive and aerospace applications due to their inherently high slot fill factor, they also present drawbacks such as the non-uniform current distribution potentially occurring across their cross section. This phenomenon is emphasized at high frequencies, leading to a significant increase of the effective conductor resistance and, consequently, of copper losses. Hence, particular attention has to be given to the design of electrical machines employing hairpin conductors, aiming to reduce the high-frequency losses as much as possible. In this paper, an analytical model based on previous investigations is updated and modified in order to increase the degrees of freedom in the design and analysis of hairpin windings. With the developed analytical model, the copper losses associated to innovative hairpin configurations can be accurately predicted. The findings also confirm that such alternative layouts can effectively reduce the Joule losses when compared to traditional hairpin technologies. © 20XX IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

International audience; This work is devoted to a Finite Volume method to approximate the solution of a convection-diffusion equation involving a Joule term. We propose a way 5 to discretize this so-called "Joule effect" term in a consistent way with the non linear diffusion one, in order to ensure some maximum principle properties on the solution. We then investigate the numerical behavior of the scheme on two original benchmarks.

International audience; The modelling and discretization of the boundary controlled 3D Maxwell’s equations as a port-Hamiltonian system is addressed. The proposed scheme, based on the PartitionedFinite Element Method (PFEM), originally proposed in Cardoso-Ribeiro et al. (2018), preserves the Dirac structure at the discrete level. Two types of damping phenomena are taken intoaccount: Joule’s effect, and a matrix-valued impedance at the boundary, both being preserved by PFEM, as presented in Serhani et al. (2019a).

This paper proposes a method to calculate Joule and hysteresis losses of thin conductive and magnetic shields in two dimensions. A known BEM formulation enforcing the Thin Layer Impedance Boundary Conditions (TLIBCs) is extended to problems involving multiple closed shields. Analytical formulae for the losses are derived. A typical geometry of shields for a three-phase conductor system is used to show that a good accuracy can be achieved.

Energy has the units of joule or kilojoule for food energy values. When energy is transferred from one object to another we say “work has been done”. How fast the energy is transferred (the rate of change of energy) is known as the power which has units of watts. Heat is the name given to the energy that is transferred from one object to another object that is at a lower temperature. The temperature of an object is a measure of the kinetic energy of its particles—roughly speaking, how fast they are moving. The units of temperature are degrees Celsius (or more correctly kelvin, where Celsius degrees = kelvin − 273).

Unlike the state variables, the volume, pressure, and temperature, other thermodynamic state functions such as the internal energy and enthalpy cannot easily be measured by a well-designed piece of apparatus. Rather, it is necessary to follow a circuitous route.