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Three-phase transformer type superconducting fault current limiter (SFCL) using two common connection points between secondary windings, which consisted of three-phase transformer windings wound on three legs of E-I iron core and two/three superconducting modules (SCMs), were suggested and its fault current limiting operations according to ground-fault types were analyzed. To verify the effective operation of the three-phase transformer type SFCL using two common connection points between secondary windings, the unsymmetrical ground and the symmetrical ground faults were applied into three-phase power simulated system with the suggested SFCL. For the comparison, the ground faults were generated into three-phase transformer type SFCL with two/three SCMs. Through analysis on the test results, the SFCL with two SCMs was confirmed to have no different fault current limiting operation from the SFCL with three SCMs. The structure of E-I iron core with three magnetically coupled legs and the constitution of three secondary windings with two common connection points were analyzed to be contributed to the same fault current limiting operation. Furthermore, the power consumption and the joule energy of the SCMs comprising both the SFCL with two SCMs and the SFCL with three SCMs during the fault period had shown to be almost the same except for the transient period due to the quench time difference in case of the single-line ground fault.

In this study, we demonstrate a carbon-based fabric Joule heater with and without a graphene oxide (GO) thin coating. The electrothermal performance of the carbon fabric used in the Joule heater was obtained using an infrared camera and by conducting electrical measurements. The outer GO could control the electrothermal efficiency and heating rate. In this research work, using the Joule heating of thin graphene films, we report adaptive thermal heating with electrical control covering temperatures ranging 30 to 50 °C (near infrared). This electrothermal GO materials can be potential nano-materials for various functional applications. Moreover, we demonstrate a general approach to achieve spin-coating of GO and confirm its biocompatibility Such biocompatibility indicates the non-toxic nature of GO, thereby extending its possible use in biomedical applications.

The current study relates to RADAR (RAdio Detection and Ranging) application for level measurement of vitrified radioactive liquid nuclear waste. The vitrification of radioactive liquid waste is carried out in special equipment called ‘Melters’. The study is directed towards the design and frequency modulation used in the level measurement of vitrified waste. More specifically, the RADAR design and frequency used for level measurement in a melter. This level measurement technique can also be used for dynamic vitrification process and can be used to measure the level variations without using any external medium/material and using only electromagnetic waves. Also, this technique is durable and accurate even under the high radioactive environment present inside the melter.

Although the equivalence of heat and work has been unveiled since Joule’s ingenious experiment in 1845, they rarely originate from the same source in experiments. In this study, we theoretically and experimentally demonstrated how to use a high-precision optical feedback trap to combine the generation of virtual temperature and potential to simultaneously manipulate the heat and work of a small system. This idea was applied to a microscopic Stirling engine consisting of a Brownian particle under a time-varying confining potential and temperature. The experimental results justified the position and the velocity equipartition theorem, confirmed several theoretically predicted energetics, and revealed the engine efficiency as well as its trade-off relation with the output power. The small theory–experiment discrepancy and high flexibility of the swift change of the particle condition highlight the advantage of this optical technique and prove it to be an efficient way for exploring heat and work-related issues in the modern thermodynamics for small systems.

Temperature-dependent Raman scattering provides valuable information on electron–phonon coupling and phonon anharmonicity of graphene. In this study, we show an enhancement of Joule heating in graphene by confining the current flow in a narrow channel. In addition, we performed a detailed analysis of the anharmonic effect in the hBN/monolayer graphene/hBN heterostructure based on the behaviour of the full-width at half maximum of the G mode with increasing electric power: a non-monotonic trend, leading to the key of approximation of the electronic temperature in graphene. We believe our results could offer a convenient analysis tool to study electron–phonon coupling and anharmonic phonon-decay processes in a high-temperature regime.

As an abundant and ubiquitous energy source, solar energy has successfully demonstrated its potential in tackling the water-energy dilemma in an eco-friendly way. In this issue of Joule, Wenbin and co-authors creatively propose the co-generation of electricity and freshwater via an integrated PV-membrane distillation system.

In this article, we will focus on the development of electrical energy storage systems, their working principle, and their fascinating history. Since the early days of electricity, people have tried various methods to store electricity. One of the earliest devices was the Leyden jar which is a simple electrostatic capacitor that could store less than a micro Joule of energy. The battery has been the most popular in storing electricity as it has higher energy density. In this article, we will describe and compare the working of various kinds of batteries and capacitors. We will review the recent technological breakthrough in electrical energy storage devices.

This paper addresses the relation between some constructive parameters of five-phase induction machines and the airgap induction distribution under operation with one phase opened; we focus on the impact of design parameters on the airgap induction and the Joule losses. The influence of design parameters of the rotor and the stator is assessed using three distinct machines as a case study: two with identical stator but different rotors, and one with a distinct stator and also a distinct rotor. The results from the case study show that the characteristics of the stator windings, such as the number of slots per pole and phase and the number of layers, have less impact on the airgap induction under fault than under healthy operation. Besides, the case study shows that a decrease in the number of rotor bars contributes to an increase in the amplitude of the third harmonic component of the airgap induction. Finally, theoretical results are validated through analysis with the finite element method.

Joule’s Energy Conservation Law was the first “meta-law”: a general principle that all physical equations must satisfy. It has led to many important and useful physical discoveries. However, a recent analysis seems to indicate that this meta-law is inconsistent with other principles—such as the existence of free will. We show that this conclusion about inconsistency is based on a seemingly reasonable—but simplified—analysis of the situation. We also show that a more detailed mathematical and physical analysis of the situation reveals that not only Joule’s principle remains true—it is actually strengthened: it is no longer a principle that all physical theories should satisfy—it is a principle that all physical theories do satisfy.

The purpose of the calorimetric sensor developed is to measure the heat flux transmitted by conduction between the human body surface and a thermostat located inside the sensor. The measurement surface has an area of 2 × 2 cm2. We have verified that the measured heat flux decreases linearly with the increase in the thermostat temperature. This allows us to define an equivalent thermal resistance between the internal temperature of the human body and the temperature of the thermostat. This equivalent thermal resistance can be determined by measuring the heat flux for different constant temperatures of the thermostat. An alternative is to perform a single measurement with linear programming of the thermostat temperature. With this type of measurement and from the calorimetric signal, it is also possible to determine an equivalent heat capacity of the skin in the measurement zone. In this article, we present the modelling and simulation of the sensor operation when the thermostat temperature varies linearly. We also present experimental measurements performed on the human body and with reference Joule dissipations.

Here, a graphene nanoribbon (GNR) field-effect transistor (FET), which includes an initial electrical defect on the GNR channel, is studied via electrical transport and scanning thermal microscope (SThM) measurements. That the spatial temperature distribution for a Joule self-heated GNR FET could be directly investigated before and after the breakdown condition. This method for investigating failures in a GNR channel will allow us to diagnose the quality of nanoscale graphene.

Analysis of recent research and publications. The problems of thermal state of billet-type bottom electrode (BE) in liquid bath of DC electric arc furnace (EAF) are associated with limited thermal conductivity of the rod in the absence of available alternative to copper-steel pair. There isn’t enough data on values of convective and Joule components of heat flux, passing through BE, initiated by electrovortex flows (EVF); regarding influence of thermophysical characteristics of transition copper-steel zone and cooling rate of BE copper part on the position of phase transition surface of steel part. Problems are considered, especially related to innovative “flat bath” steelmaking technologies, in which the possibilities of dead time pauses for periodic renewal of the BE body due to “EVF-off” are significantly limited.Purpose. To investigate the effect of EVT on the thermal state of bottom electrode and to develop on this base the energy efficient BE solutions.Methodology. Numerical simulations of BE thermal state and an industrial testing of essentials. Findings & Originality. For the first time, the joint effect of EVF, Joule heat, and characteristics of BE transition zone copper – steel on the position and equilibrium thickness of solid steel part of the BE, which determines the energy efficiency of DC EAF operation, was comprehensively studied.Research implications. Numerical simulations of EVF in DC EAF steelmaking bath and heat transfer with a phase transition through BE were carried out. The heat flux density and local EVF velocity in anode well are 1.8–2 MW/m2 and 0.75 m/s, respectively. Equilibrium thickness of solid steel BE part is critically dependent on the width of copper-steel transition zone, should not exceed 20-25 mm. Contribution of Joule component of total thermal load on the BE does not exceed 20%. Intensification of cooling rate above ≥ 20 kW/(m2K) practically doesn’t affect the BE solid steel part thickness.Practical implications. Manufacturing technology of BE with a narrow transition zone by the method of two-stage electro-slag welding of copper on a steel billet, which ensures stable DC EAF operation and increases energy efficiency, has been improved.

The resistance spot welding (RSW) stands different over other welding techniques as the actual weld nugget is shaped internally relative to the surface of the base metal. The weld formed is fundamentally a mix of heat, pressure and time. The welding conditions are precisely controlled to produce sound nuggets. The application of interface pressure allows accurate prediction of interfacial heat and electrical resistance, which plays a dominant role in Joule’s heat generation. In this work, lap welding using resistance spot welding has been numerically investigated for Mild steel (G-3302) and Stainless steel (SS-202) sheets. Spot welding has been completed by utilizing a 35 kVA DC type resistance spot welding machine, constrained by a Programmable Logic Controller unit. For both materials, two spots, three spots and four spots weld were done in order to obtain various comparative results. The weld nugget formation has been simulated using SIMULIA. The 3D model has been created by using GUI of commercial FEA package ABAQUS 6.14. The model employs coupled thermal-electrical-mechanical analysis. Simulation has been performed for pertinent parameters in ABAQUS 6.14. The obtained plots from numerical model are found to be in strong consistency with experimental data.

Intelligent, highly conductive, robust, and flexible electronic textile-embedded smart devices hold surging interest in the wearable personalized heating system or thermotherapy. However, designing of these structures with desirable thermotherapy properties hinges on certain aspects such as fast temporal responsiveness, localized tunable heating characteristics, reliability, and stable conductive media over several mechanical disturbances as well as readily scalable opportunities. To address these issues, in this work, a facile and scalable dip-coating approach was devised to develop a stretchable, thermally stable, and electroconductive composite cotton textile with reduced graphene oxide (rGO) and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) (CGP). The electromechanical properties of CGPs were greatly enhanced due to crystallographic and intra-intermolecular hydrogen bond energy/distance modification. The CGPs fabricated through the systematic dip-coating and drying approach demonstrated outstanding morphological synergies and structural benefits, providing effective endurance against deformations with excellent stable heating up to 60% strain. The composite heater endowed rapidly responsive (15–25 s) Joule heating characteristics, stable heating/cooling cycle and excellent durability to wash. The real-time operation of a wearable fabric heater attached to the finger and palm area of the hand is presented, suggesting its excellent avenues in the personalized electronic healthcare system through tunable and specific region-wise body temperature management for thermotherapy applications.

The impact of the thickness of the magnetic and nonmagnetic layers in an axially laminated anisotropic (ALA) rotor in a synchronous reluctance motor (SynRM) aimed at high-speed applications was studied. Considering possible manufacturing issues, the layers are desired to be thick rather than thin. At the same time, the layer thickness is related to the electromagnetic capabilities of the ALASynRM. In the study, a 12 kW ALASynRM was considered. As a reference, a 12 kW IM with a smooth solid rotor with copper end rings was used for comparison with the designed ALASynRM. The manufacturing procedures of an ALA rotor with certain materials were verified in practice. Strength tests of the samples were implemented showing the suitability of the selected materials for application in the prototype. In the electromagnetic design, the thickness of the ALA rotor layers has shown to have a significant impact on the rotor eddy current losses. The stator iron losses and the winding Joule losses also depend on the rotor design. Torque ripple is considerably affected by the thickness of the rotor layers and their position in relation to the stator slots.

Recent years have seen a rapid increase in the level of sophistication in modern day devices which has given rise to the demand for better performance in all of their components, one of which is the heating element. Two excellent approaches to this need would be to improve the materials from which these Joule’s heating elements are made and the other to design improved heater geometries for best temperature distribution. In this paper, we discuss a high performance electrothermal heater prepared from laser reduced graphene oxide (LrGO) deposited on Polyethylene Terephthalate (PET) flexible Substrate. The surface morphology and structural properties of the prepared LrGO films were investigated by means of Scanning Electron Microcopy (SEM), X-Ray Diffraction (XRD) and Raman Spectroscopy (RS). Electrothermal (ET) responses of the fabricated electrothermal heaters to different driving DC voltages were studied by Infrared thermal Imagery. An electrothermal heater with a low Sheet resistance of ∼52 O/square was fabricated and it can attained a steady state temperature of up to 135 °C in only 10 s when a low voltage of 9 V was applied. A finite Element model (FEM) was prepared for this heater which agreed well with the experimental results. Power consumption for this heater is as low as 0.389 W/cm2, making it a suitable candidate for energy-saving applications such as wearable electronic.

We report the demonstration of a diode-pumped Tm:YLF laser operating at 1.88 µm that produces pulse energies up to 3.88 J in 20 ns. The compact system consists of a Q -switched cavity-dumped oscillator generating 18 mJ pulses, which are then amplified in a four-pass power amplifier. Energies up to 38.1 J were obtained with long-pulse amplifier operation. These results illustrate the high energy storage and extraction capabilities of diode-pumped Tm:YLF, opening the path to high peak and average power mid-infrared solid-state lasers.

Sustainability aspects of electrical machines are in today’s e-mobility market one of the main requirements together with high efficiency, high power density and low cost. In this paper the environmental impact of the electrical machine is being lowered looking at aluminium hairpin stator winding instead of the conventional copper hairpin winding. Two machines are designed using a multi-objective genetic optimization process with different objectives and compared with a copper hairpin machine design. The increase in resistivity has a non negligible impact on the joule losses, however it tends to mitigate AC effects. Overall, the aluminium hairpin solution is shown to be a sustainable and valid alternative for e-mobility applications.

With the development of femtosecond (fs) laser technology, an fs laser pulse with 10s of Joule, even 100s of Joule energy is available and the focused laser intensity can be expected to induce the pure Coulomb explosion of the cluster with a much larger average radius than before. Meanwhile, the production of gas cluster with an average radius of upto 10s of nanometer has been possible. In this case, it is necessary to reinvestigate the feasibility of 109 n/shot neutron yield for the practical application in the intense fs laser-driven nuclear fusion. In this work, the neutron yield from the explosions of the D2 clusters of 6–20 nm average radius at the 0.5–100 J pulse energy and the CD4 clusters was investigated theoretically. It is found that the optimum neutron yield of 109 n/shot can be obtained at the laser energy and the cluster radius currently available. However, a clustered-gas jet with a large cross-section is demanded to match the proper plasma diameter.

Welding technology is used because besides being easy to use, it can also reduce costs so it is cheaper. Especially for welding repair. From the welding repair the extent to which the strength of GMAW welds can repair components from the molded plastic mold room made of AISI 420 stainless steel. Repair of the print room components using deposit welding is tested using tensile strength and hardness as realization of resistance when holding the rate of liquid plastic entering the print room by 25 to 40 MPa, depending on the plastic viscosity, the precision of the mold and the filling level of the print room. Deposition welding method as a welding repair can affect a procedure to be able to produce a component that is safe and capable of being used in accordance with the provisions. The welding process used is reverse polarity GMAW DC with 125 A current and ER 70 S welding wire diameter 1.2 mm. Test material AISI 420. Tests carried out were tensile test, impact test and hardness test in weld metal, HAZ and base metal. From the Charpy impact test and tensile test obtained the value of welding strength which is close to the strength of the complete object, which is equal to 65%. The energy absorbed by the impact test object with GMAW welding is 5.4 Joule while for the whole test object is 8.1 Joule. The welding tensile strength is 520 MPa compared to the tensile tensile strength of 820 MPa.

Purpose The purpose of this paper is to optimize the configuration of a heat sink with phase change material for improving the cooling performance of light emitting diodes (LED). Design/methodology/approach A numerical three-dimensional time-dependent model is developed with COMSOL Multiphysics to simulate the phase change material melting process during both the charging and discharging period. Findings The model is validated with previously published works. It found a good agreement. The difference between filled cavities with phase change materials (PCM) and alternate cavities air-PCM is discussed. The last-mentioned showed a good ability for reducing the junction temperature during the melting time. Three cases of this configuration having the same total volume of PCM but a different number of cavities are compared. The case of ten fins with five PCM cavities is preferred because it permit a reduction of 21 per cent of the junction temperature with an enhancement ratio of 2:4. The performance of this case under different power input is verified. Originality/value The use of alternate air-PCM cavities of the heat sink. The use of PCM in LED to delay the peak temperature in the case of thermal shock (for example, damage of fan) An amount of energy is stored in the LED and it is evacuated to the ambient of the accommodation by the cycle of charging and discharging established (1,765 Joule stored and released each 13 min with 1 LED chip of 5 W).

Alternating current electrothermal flow (ACET) induced by Joule heating is utilized to transport biologically relevant liquids in microchannels using simple electrode designs. However, Joule heating may cause significant temperature rises, which can degrade biological species, and hence, ACET may become impractical for biomicrofluidic sensors and other possible applications. In this study, the temperature rise at the electrode/electrolyte interface during ACET flow is measured using a high-resolution, noninvasive, thermoreflectance imaging method, which is generally utilized in microelectronics thermal imaging applications. The experimental findings reveal that Joule heating could result in an excessive temperature rise, exceeding 50 °C at higher voltage levels (20 V

Controlling thermal radiation in nanoscale is critical for verifying the Planck’s law in subwavelength limit, and is the key for a range of innovative technologies including energy, display and sec...

A calorimetric sensor has been developed for the measurement of the heat power dissipated by a superficial and localized area of the human body. In this work we present a method for the determination of the transient heat flux between the surface of the human body and the thermostat located inside the sensor. This method consists of the reconstruction of the calorimetric signal (CSRM) from the hypothesis that the power measured by the sensor is adjusted to a mathematical model consisting of a sum of exponentials of the form Wbody (t) = A0 + ∑ Ai exp (−t/τi). We show the experimental results obtained on the human body and on Joule dissipations of reference, by applying this new method (CSRM) and also the inverse filter method (IFM). The CSRM method allows to easily separate and identify the different phenomena that take place in the dissipation, from the instant the sensor is placed on the surface where the dissipation takes place, until the power reaches the steady state, and also in the instant the sensor is removed from the surface and placed back in its base. This sensor allows to obtain the power dissipated by a surface of 4 cm2 with a resolution of 10 mW. In relation to the dissipation measured in the different areas of the human body, this sensor will allow to study the possible correlations between these transient phenomena and the human physiopathology.

Air-cored machines offer benefits in terms the elimination of magnetic attraction forces between stator and rotor. With no iron in the stator there is not a good thermal conduction path for heat generated by Joule losses in the stator winding. Results from both models and experimental tests are provided in this paper to investigate different methods of cooling air-cored windings, including natural air-cooling, direct liquid cooling, and the use of heat pipes.

Conductive graphene electrode of large area is required for some applications like for example photovoltaics or touch screens. Such large area graphene membrane needs specific test methods to assess defects which may obstacle its performance. In this work the infrared imaging of Joule heated graphene was proposed to estimate its uniformity and mechanical continuity. Thermal signatures of the typical mechanical defects like scratches and local resistivity inhomogeneity were identified. Distribution of the heat emission around such defects were simulated using finite elements method and then experimentally verified by recording of thermal landscape around the corresponding real graphene defects. Proposed method gives micrometric resolution and ability to inspection of large area electrodes depending on applied optics. Presented results give suggestions how graphene imperfections generate observed hot points related to graphene layer defects.

We propose a new concept on theoretical explanation of the relationship between transient non-bonded interaction and thermo-mechanical behavior on rubber-like materials. The theoretical equation can describe the extension ratio dependence of stress and temperature simultaneously. The approach found important evidence on the presence of the uncertainty relation between non-bonded interaction and angular momentum of molecular chain. We applied this concept to analysis for thermal molecular motion of Joule's experiments on thermo-dynamic properties of the vulcanized rubber. Our theoretical approaches, at least, provide the important parameters; the number of non-bonded interaction, the fluctuation energy, the attractive energy, the radius of rotation, the finite extensibility effect and the effective molar mass. These parameters can be used as a rule of thumb guide for multi-physics design in the future work to bridge the atomic behavior and the thermo-mechanical behavior which is associated with various rubber properties such as energy loss, damping, flexibility, friction, heat build-up, fatigue and fracture.

This paper deals with analyzing losses of three-phase high current and low voltage inverter, which is intended for automotive applications. High current inverters are becoming more popular in automotive area due to increasing the number of high power electrical drives in cars and trucks. The less reliable and less efficient, usually mechanical drive systems are replaced for more effective and more reliable electrical drive systems. There are liquid pumps, HVAC blowers, turbochargers, etc. Total losses of the common inverters are divided into three main parts, conductive and joule losses, switching losses and additional losses. The highest part of losses usually generates power switches, in this case MOSFETs. The size of other part of losses is determined by parameters of used components, i.e. DC-link capacitors, shunt resistor sensors, etc. The power losses and efficiency of inverter are analyzed by using the simulation model in LTspice. The model of inverter contains spice models of MOSEFTs and DC-link capacitors. The parasitic components of high current and excitation traces are also included into model. The analyzed inverter contains only DC-link shunt resistor for current sensing purpose in order to minimize joule losses of shunt resistors. Joule losses of shunt resistor, DC-link capacitor losses, reverse polarity battery protection MOSFET and three-phase half-bridge inverter are analyzed from power losses and efficiency point of view. The final result of this paper describes the size of losses of power circuit and the value of efficiency of inverter, which the high current inverter is able to reach.

This was a case report which described the background, method, and test results of the effect of 3 wavelength lasers transmeatal irradiation treatment on motion sickness, using combined lasers with an output of 2.5 mW @ 532 nm 10.0 mW @ 808 nm 2.0 mW @ 1064 nm for transmeatal irradiation treatment. 10 patients aged 50 ± 25 were treated with MWLLLTI at a dose of 104 Joule in total for both ears per day for 15 consecutive days. It was found that MWLLLTI stimulation was effective in motion sickness treatment.

Applied to the production of windings, the PCB technology is promising for developing high performance slotless permanent magnet machines, since it makes possible to envisage winding shapes and topologies difficult or impossible to achieve by the classical wire technology. However, compared to wire windings, PCB windings are more subject to eddy current losses because of their high width-thickness ratio. To counteract these eddy currents, the conventional solution consists in reducing the track width but in conjunction with an increased number of turns. That requires, in order to keep the supply voltage constant, to consider parallel connections of conductive tracks at the winding terminals. This paper tackles the eddy current problem differently by adding some slits distributed along the conductive tracks. This amounts to carry out local parallelizations without impacting the motor supply voltage. This study, through a parametric analysis of different slitting possibilities in wave windings, shows that reconnect parallel sub-tracks at one end-winding of two delivers nearly the same results than a classical full parallelization but with a potential simplification of the interconnections between the PCB tracks constituting the winding. Furthermore, it shows that this conclusion is independent of the winding shape considered.

This study presents a lamp-pumped Nd:glass laser system capable of achieving joule level output energy at 1-Hz repetition rate with high beam quality. The 1.8 J of energy in a 5 ns pulse was achieved with 1.5 mJ injected energy. The laser system includes a beam shaping module and an eight-pass, lamp-pumped amplifier. The laser amplifier demonstrated long-term energy stability of 1.76% PV and 0.29% RMS when operating at 1.8 J for 30 minutes. In a longer period of operation, no damage or obvious beam degradation was found. A uniform gain distribution with a single-pass small-signal gain of 3.89 was acquired with the four-lamp-pumping method, and thermally induced wavefront aberration was mitigated. Finally, a high beam quality was obtained using a homemade optically addressed liquid crystal light valve. After compensation, the near-field modulation decreased from 1.38 to 1.21, meanwhile, the beam contrast decreased from 6.54 to 4.71%. In terms of the far-field quality, a 90% far-field energy concentration was 2.5 times the diffraction limit.

Radiographic imaging is an omnipresent tool in basic research and applications in industry, material science and medical diagnostics. Often, the information contained in more than one modality can be valuable, but difficult to access simultaneously. This talk reviews developments in laser-plasma-accelerators for protons, electrons and x-rays from solid and gas targets for multimodal imaging. Laser-driven ion acceleration and x-ray generation have been investigated using tungsten micro-needle-targets at the Texas Petawatt laser [1]. The experiments and supporting numerical simulations reveal peaked proton spectra around 10 MeV with significant particle count and a strong keV level x-ray source. The source size for both has been measured to be in the few-µm range. Both sources were eventually applied to simultaneous radiographic imaging of biological and technological samples. In recent experiments at BELLA Center’s high repetition rate 100 TW dual-arm laser, steps were taken towards bi-modal x-ray and electron imaging of dynamic events such as hydrodynamic shocks, in which often both density and electro-magnetic fields are important quantities to measure. Here, a shock was driven by a 1 Joule, 200 ps laser focused in a 30 µm wide water jet. A laser wakefield accelerator was driven by a second 2 Joule, 40 fs laser in a gas-jet target, providing both 150 MeV electrons and broadband betatron x-rays up to ˜10 keV for projection imaging. This research aims to leverage unique properties readily available in laser plasma accelerators for applications. Specifically, the emission of pulsed, bright, multimodal bursts of radiation can open new ways in biological imaging (e.g., with ns-synchronized ions and x-rays) and in high-resolution diagnostics for high-energy density science (e.g., with fs-synchronized electrons and x-rays). [1] T. M. Ostermayr et al., “Laser-driven x-ray and proton micro-source and application to simultaneous single-shot bi-modal radiographic imaging,” Nat. Commun., vol. 11, no. 1, pp. 1–9, Dec. 2020. This work was supported by the DFG via the Cluster of Excellence Munich-Centre for Advanced Photonics (MAP) and Transregio SFB TR18. This work has been carried out within the framework of the EUROfusion Consortium and has received funding, through the ToIFE, from the European Union’s Horizon 2020 research and innovation program under grant agreement number 633053. The authors acknowledge funding by the Air Force Office of Scientific Research (AFOSR)(FA9550-14-1-0045, FA9550-17-1-0264). Work supported by DOE FES under grant DE-SC0020237. Work supported by US DOE NNSA DNN R&D, by Sc. HEP, by the Exascale Computing Project and by FES LaserNetUS under DOE Contract DE-AC02-05CH11231.

We investigate hot carrier propagation across graphene using an electrical nonlocal injection/detection method. The device consists of a monolayer graphene flake contacted by multiple metal leads. Using two remote leads for electrical heating, we generate a carrier temperature gradient that results in a measurable thermoelectric voltage VNL across the remaining (detector) leads. Due to the nonlocal character of the measurement, VNL is exclusively due to the Seebeck effect. Remarkably, a departure from the ordinary relationship between Joule power P and VNL, VNL ∼ P, becomes readily apparent at low temperatures, representing a fingerprint of hot-carrier dominated thermoelectricity. By studying VNL as a function of bias, we directly determine the carrier temperature and the characteristic cooling length for hot-carrier propagation, which are key parameters for a variety of new applications that rely on hot-carrier transport., We acknowledge the support from the European Research Council (ERC Grant Agreement No. 308023 SPINBOUND), the Spanish Ministry of Economy and Competitiveness, MINECO (under contracts MAT2013-46785-P and Severo Ochoa Program SEV-2013-0295), and the Secretariat for Universities and Research, Knowledge Department of Generalitat de Catalunya. J.F.S. acknowledges support from the Juan de la Cierva (JCI-2012-12661) and the Beatriu de Pinós programs, and M. V. C. from the Ramón y Cajal program (RYC-2011-08319).

We demonstrate the highest efficiency ($\sim$80%) second harmonic generation (SHG) of Joule level, 27 femtosecond, high contrast pulses in a type-I lithium triborate (LBO) crystal. In comparison, potassium dihydrogen phosphate (KDP) gives a maximum efficiency of 26%. LBO thus offers high intensity ($>$10$^{19}$ W/cm$^{2}$), ultra-high contrast femtosecond pulses, which have great potential for high energy density science particularly with nanostructured targets as well as technological applications., 5 pages, 3 figures, 2 tables

In this chapter, we report our latest work on the technical development of the cryogenically cooled Yb:YAG-ceramics laser as scalable technology toward achievement of repetitive kilo-joule-class lasers. In our first trial, we obtain a high small signal gain of 20.4 with a high stored energy of 149.0 J using a conductively side-cooled Yb:YAG ceramic multi-disk laser amplifier operating at 100-K cooling temperature. In the second trial, we obtain 117-J nanosecond pulsed laser output with a cryogenic-helium-gas face-cooled Yb:YAG ceramic multi-disk laser amplifier. In this study, we obtain 42.3% energy-extraction efficiency from the energy stored in the Yb:YAG ceramic disks. We also determined the specifications of the face-cooled laser amplifier designed for repetitive operation by flowing helium gas on the end faces of the Yb:YAG ceramic disks. The feasibility of a practical design for kilo-joule-class diode pumped solid state lasers with a cryogenically cooled Yb:YAG ceramic disks was demonstrated by the developed high-gain and high-efficiency laser technologies.

We report on the recent development of a thin-disk laser system providing 720-mJ, sub-picosecond pulses at 1030 nm. The CPA system is operating at 1 kHz and was specially designed for applications in laser-based lightning rod.

This article presents a postfault control algorithm that minimizes the stator Joule losses in multiphase induction machines under an open-phase fault and for different star connection layouts. The key novelty is that the algorithm can be applied to any configuration of a multi- n -phase machine, independently of the connection of the neutral points. The latter is analytically derived and is based on the space vector representation of the machine model. In addition, it is shown that a low number of neutral points helps to reduce the winding losses in case of an open-phase fault but requires additional control regulators and computational efforts. The theory is applied to an asymmetrical quadruple-three-phase induction machine, which is configured to represent five different motor layouts. Finally, experimental results are presented to validate the control algorithm. The optimal solution that is given in this article can be employed for the control of symmetrical or asymmetrical multiphase machines with different star connection layouts and in any open-phase postfault operation.

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.

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.

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.

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.

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.

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.

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.

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.

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.