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This paper is aimed at studying an unsteady hydromagnetic flow of a viscous incompressible electrically conducting reactive fluid in a permeable channel with asymmetrical convective boundary conditions in a rotating reference frame under the Arrhenius kinetics with neglect of the reactant consumption. Asymmetrical convective heat exchange with the surrounding medium at the channel surfaces follows the Newton law of cooling. A chemical reaction in the flow system is exothermic and assumed to follow the Arrhenius rate law. The heat transfer characteristics of the flow are considered with viscous and Joule dissipations taken into account. The expressions for the velocity components obtained in closed form are used to calculate the wall shear stresses. The energy equation is tackled numerically with using MATLAB. The effects of the pertinent parameters on the flow dynamics are analyzed graphically. The results reveal that the combined effects of magnetic field, rotation, suction/injection, and convective heating substantially affect the flow characteristics in the channel.

The intrinsic factor of crack defect in continuous casting slab is determined by the high-temperature mechanical properties of slab itself. At present, the measurement for the thermal mechanical properties is mostly achieved by Gleeble Hot-Tensile test. However, the uneven temperature distribution in the specimen during the test will definitely affect the accuracy of the measured mechanical properties. To acquire accurate high-temperature mechanical properties, studies of the temperature distribution in the tensile specimen and its effect on mechanical properties is significant. In this paper, A three-dimensional electromagnetic model and a three-dimensional Joule thermal model for the as-cast steel specimen in Hot-Tensile test were built to study current density and temperature distribution in the specimen. It was found that temperature difference between surface and center of steel specimen reaches 62 °C, when the test temperature is 1300 °C. An average absolute difference method was used to calibrate the inhomogeneous distribution of temperature. Compared with the original test, the difference of the tensile strength between the calibrated and original test decreased from 26 to 10 MPa with test temperature increasing from 800 °C to 1300 °C.

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.

The thermal implication of peel stresses and Joule and Thomson heating on the delamination of photovoltaic-thermoelectric generator (PV-TEG) layers is modelled and established numerically. The scope of the study embraces simulation of the hybrid system with and without electric potential difference. Furthermore, the results obtained from the interfacial peel stresses demonstrate that uneven contractions occur in the layers of the hybrid system, resulting in delamination. In addition, the conductor strip/TEG interface has the highest peel stress with a numerical value of 0.13 GPa, while the glass/ethyl vinyl acetate (EVA) interface presents a contrasting stress pattern in comparison to the EVA/cell, EVA/back plate and conductor strip/TEG interface. However, the n-type leg of the TEG has a higher thermal stress in comparison to the entire system components resulting from the application of 7 mV electric potential. Finally, this paper demonstrates that thermal stress is extremely deleterious in the TEG in comparison to the PV module. As a result, device failures will commence from the thermoelectric legs, with the n-type leg having a shorter operational life in comparison to the p-type leg.

This paper presents thermo-mechanical modeling on multilayered metallic microstructures consisting of two bilayers that enable 3D deployment once being Joule heated. A representative design of such microstructures, as well as their working principle is introduced. A mathematical model is derived using Euler–Bernoulli beam theory, and analytical solutions describing out-of-plane displacement of the multilayered microstructures when uniformly heated, which is validated by finite element analysis. Parametric analysis on thermal load and dimensional change of beam shows a good agreement between the analytical solutions and results given by finite element analysis. The phases of the near-equiatomic NiTi layer are analyzed by EDS and XRD, which prove to be austenite during the Joule heating process. The mechanical properties of austenite NiTi are incorporated into the analytical solutions that provides a good estimation of 3D deployment of microstructures made of NiTi and aluminum. The experimental results provide an approximately 7 µm out-of-plane deployment by applying a uniform temperature increase of 132 K, and parametric analysis on the dimension of top aluminum beam offers another promising approach to larger 3D deployment. The proposed mathematical model provides an efficient tool for predicting the out-of-plane deployment of such multilayered microstructures.

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.

The focus of this paper is one of James Prescott Joule’s scientific contributions: the laws of heat production by electric currents in conductors. In 1841, the 22 years old Joule published a paper with the title “On the heat evolved by metallic conductors of electricity, and in the cells of a battery during electrolysis” where he presented an experimental study of that phenomenon and proposed two laws that were allegedly supported by his trials. On closer inspection, both his laboratory work and his inferences can be challenged. The emphasis of this article is an attempt to understand Joule’s experimental undertaking, its highpoints and shortcomings, by a detailed analysis of this specific episode and by studying the precedents of his work and subsequent advancements. It is possible to point out several serious deficiencies of that investigation, and Joule’s contemporaries, such as Edmond Becquerel and Heinrich Lenz, did criticize some of his flaws and undertook new experiments to provide a sound basis for those laws. Besides providing a historical examination of that specific episode, this article uses this case study to tackle some features of the nature of science that may contribute to scientific education.

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.

A re-visitation of Joule’s experiment motivates a critical analysis of thermodynamic notions: heat, total energy, first principle, organization of a scientific theory, its relationships with logic and mathematics. A rational re-construction of thermodynamics is suggested according to the model of a problem-based organization, that Sadi Carnot applied to his formulation. The new formulation accomplishes the long time theoretical process started by Joule’s experiment within physicists community's collective mind, i.e. the process of exiting out Baconian science for suggesting a first theory out Newton’s paradigm, and eventually for introducing a pluralism of incompatible physical theories.

The principle of conservation of energy tells us that ‘energy can neither be created nor destroyed but only transformed’. The validity of the principle is without question. The problem is the concept. Contemporary physicists have asserted that we do not know what energy is. We find, however, 19th century physicists, contemporary physicists and historians of science who converge on the point: Mayer and Joule discovered energy. Therefore, we do not know what energy is, but we know these authors discovered it. What did they then discover? What can we learn from this with regard to the energy concept problem? To deal with this issue, I will distinguish between what the authors did experimentally and what they said about the phenomena. This method of analysis makes the difference in relation to historical works on the subject. In a second step, I will consider the introduction of the energy concept, which is from 1850s, and the reification of the energy in 1880s. Finally, I will address the energy conservation principle and the concept of energy conveyed by this principle in contemporary textbooks. As we shall see, the conservation of a magnitude that we call energy nowadays was discovered by Mayer and Joule; an indestructible and transformable entity was not. Adopting the original conservation principle would be enough to avoid the energy concept problem.

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.

This paper specifically talks about optimized design strategy of sub-kilo Joule Dense plasma focus (PF) fusion device in a full-fledged systematic manner. Recently, there are many pulsed power groups working in design and development of various PF devices in the range of sub-kilo joule energy. Few of them are publishing with the optimized operating parameters for the maximum neutron yield. Most of them, talks about the estimation of PF parameters based on traditional high voltage break down mechanisms in vacuum, plasma pinch behavior and neutron generation, which are optimized for higher energy level (few kJ to MJ) PF devices. It has been very tricky and iterative way to achieve maximum neutron yield for a sub kJ PF device. A conceptual design strategy is presented for estimation of four critical PF tube parameters. These four parameters are: Anode radius, cathode radius, effective anode length and insulator length. This is very important to know these parameters, in advance of actual fabrication and plasma pinch experiments. A 400 J PF device is designed and operated at 20 kV with the help of above design strategy in single go. Maximum neutron yield is measured 50% higher with wide range of deuterium gas pressure (6–12 mbar) among sub kJ PF devices. A detailed design strategy, experimental pulsed power system development, neutron measurement and results are discussed.

International audience; History of science provides access to a reservoir of meaningful experiments that can be studied and reproduced in classrooms. This is the case of Joule’s paddle-wheel experiment which displays the potentiality to help students improve their understanding of the concept of energy. This experiment has been mentioned in many physics textbooks during the 20th century. Recently, it has received renewed attention by several researchers in science education. However, the accounts of Joule’s experiment proposed by these researchers are at variance with each other: either in terms of equivalences, in terms of energy change, or in terms of energy transformation and Rankine’s definition. This raises several questions: What is their respective contribution to the understanding of the historical emergence of the energy concept, and to the understanding of the very meaning of this concept? Are these accounts concurrent? Eventually, how can they help for the teaching energy? To investigate these questions, historical details concerning this experiment are first considered. It is stressed that Joule did not made use of the concept of energy, and instead described his experiment in terms of conversion of living force into heat. The three accounts of Joule’s experiment are then presented and their respective contribution discussed. By emphasizing different aspects of this experiment, they are shown to suggest different strategies for teaching energy. For all that, they are not contradictory and, considered together, they bring to light the great potential of Joule’s experiment to foster students understanding of this concept.

Signal amplitudes of low-temperature detectors, vastly used in rare-event searches such as neutrinoless double beta decay experiments, are sensitive to measurement conditions causing instability such as operation temperature fluctuations. Those detector signal amplitudes thus present drifts and shifts over time due to those temperature fluctuations and need to be corrected. This effect degrades the energy resolution and particle discrimination capabilities of the calorimetric detection at low temperatures, with both strongly affecting the sensitivity of rare-event search experiments. Joule heaters were developed and used on absorber crystals in the Advanced Mo-based Rare process Experiment project, to inject periodically a controlled amount of heat, and thus produce reference signals that can be used to correct and thus stabilize the signal amplitudes of the detectors. The pulse height of the heater signals could not be used as a correction parameter as it was affected by various sources of instability. Instead, the rise time of the heater signals was used to generate a correction function describing well the time dependence of the particle-induced events in the crystals and thus provided a significant improvement of the energy resolution and particle discrimination capabilities to separate $$\beta /\gamma$$ and $$\alpha$$ events.

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.

This paper presents an electrical performance design method of mechatronic circuit breakers (CB) based on multi-domain sequential coupling (MSC). Firstly, the attraction force of electromagnetic trip mechanism is obtained by Maxwell formula and Ampere’s circuital law. The multi-body kinematics and dynamics model of CB are built by recursive Euler–Lagrange partial differential equations using generalized coordinates. The electrical performance optimization model of CB is built to obtain the optimal opening angle, clearance and over-travel of the contact. The MSC piecewisely combines one field with another field according to the variation and sensitivity of the unstable field to perform multiphysics simulation such as magnetohydro-dynamics (MHD). The physical experiment of rated short-circuit capacity is carried out to verify the proposed method using infrared thermogram. The peak voltage, Joule integral and on–off time of the CB are optimized and shortened with maximum change of ratio 8.13% which proves that the CB has better reliability with longer mean time between failures.

We study parametric resonance (PR) of double-clamped micro-beams that are electro-thermally actuated by a time-dependent Joule’s heating and cooled by a steady air flow. The developed model demonstrates applicability of such device as a bifurcation-based flow velocity sensor. An AC electric current through the beam induces a time-harmonic compressive force that leads to parametric excitation of the structure. Convective cooling due to the air flow affects the location of the parametric transition curves on the driving voltage–frequency plane. The flow velocity can be obtained by measuring the frequency corresponding to the steep amplitude transition of the response. The device is modeled as an Euler–Bernoulli beam with an axial force parameterized by the electric current. The heat transfer problem is solved analytically; the heat flux due to the air flow is calculated using empirical correlations. The behavior of the beam is studied numerically, by means of finite differences, and analytically, using an approximate single degree of freedom Galerkin model, reduced to the Mathieu–Duffing equation. We show that while the PR always emerges at the driving voltage/current below the critical static buckling value, practical realization of the purely electro-thermal parametric excitation is challenging and is highly influenced by the device dimensions and quality factors. We evaluate the parameters required to assure the PR and demonstrate, using the model, feasibility of the suggested flow-sensing approach in the devices of realistic dimensions.

Quality of resistance spot-welded joints depends on Joule’s heat generation and, in turn, a current profile, dynamic resistance change, and its initial value. In the present work, the impact of electrode force and dome radius of hemispherical electrodes on initial resistance between electrodes was investigated. Two combinations of workpieces of zirconium alloy thickness of 0.25 + 0.25 mm and austenitic stainless steel thickness of 0.3 + 0.3 mm were used. The experimental results obtained were compared with calculated values using published equations and data on physical properties of these materials. After that, the possibility of stabilization resistance between electrodes by preheating current pulses was studied. The pulses had different algorithms of current rise: discrete and stepwise, as well as sharp and smooth with longer upslope. The results show impossibility of reliable prediction and absolute stabilization of initial values of resistance between electrodes. No clear relationship between these values and electrode force has been found. An increase in dome radius of hemispherical electrodes reduces mean resistance values for zirconium alloy but has no effect for stainless steel. Also, it does not affect dispersion of values for both materials. The rate of preheating current rise has no appreciable effect on stabilization of resistance between electrodes in all cases. Stepwise current rise significantly reduces dispersion of resistance values for zirconium alloy but has no effect for stainless steel. However, their dispersion significantly decreases after preheating in comparison with initial values.

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.

Joule heats which are generated by coals in an applied electric field are directly correlated with variation resistivity of electrical parameters of coals. Moreover, the joule heating effect is closely related with microstructural changes and relevant products of coal surface. In the present study, a self-developed applied direct current (DC) field was applied onto an experimental system of coals to investigate variation resistivity of electrical parameters of highly, moderately and lowly metamorphic coal samples. Moreover, breakdown voltages and breakdown field intensities of above three coal samples with different metamorphic grades were tested and calculated. Variation resistivity of electrical parameters of these three coal samples in 2 kV and 4 kV DC fields were analyzed. Results show that internal current of all coal samples increases continuously and tends to be stable gradually after reaching the “inflection point” at peak. The relationship between temperature rise effect on anthracite coal surface in an applied DC field and electrical parameters was discussed. The temperature rise process on anthracite coal surface is composed of three stages, namely, slowly warming, rapid warming and slow cooling to stabilize. The temperature rise effect on anthracite coal surface lags behind changes of currents which run through coal samples. There’s uneven temperature distribution on anthracite coal surface, which is attributed to the heterogeneity of coal samples. In the experiment, the highest temperature on anthracite coal surface 65.8 ℃ is far belower than the lowest temperature for pyrolysis-induced gas production of coals 200 ℃. This study lays foundations to study microstructural changes and relevant products on coal surface in an applied DC field.

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.

Laser-induced breakdown spectroscopy (LIBS) has been extensively applied due to the capabilities of real-time, multi- phase and multi-element analysis. With the advantages, portable LIBS is in rapid development with great potential of field measurements. In this work, a portable LIBS was developed by a 50 μJ level laser for excitation and an objective lens for focusing or imaging. Element detection was successfully achieved by this setup, and also the microscopic observation could be obtained with the magnification of 350×. A preliminary investigation was carried out for mineral recognition by the developed portable LIBS. The obtained results indicate that the element detection combined with micro observation was an effective way for recognizing minerals, especially for similar mineral identification or discrimination. It is suggested that the micro-joule laser could be alternative for the commercial portable LIBS, and the on-site mineral or rock recognition is a promising field for the application.

In this paper, we have considered a methodical approach to forecast the consequences of the influence of pulsed electromagnetic fields on electronic devices based on three defined conditions of the disruption of device functioning. The approach is based on the use of key parameters of pulse disturbances in critical circuits of electronic devices. Depending on the problem being solved and features of the object being tested, the key parameters can be: the amplitude of a voltage pulse in a critical circuit of an object; the Joule integral; the energy; the frequency of repetition of influencing pulses; the probability of a bit error; the number of errors in a transferred data packet; the data rate, etc.

Naval propulsion is facing mutations toward electrification of propulsion system. In naval propulsion applications, motors and drives are required to be highly fault tolerant. For reasons such as reliability, smooth torque and partition of power multiphase motors appears to good candidates for electrical marine propulsion. Permanent magnet machines are preferred over others because of their higher power densities and efficiencies, allowing a more compact and efficient propulsion system design. In this paper, a comparison between two open-circuit fault-tolerant control techniques for 5-phase permanent magnet machines (PMSM) with trapezoidal back EMF is presented. The first technique is an off-line one based on the instantaneous power balance and the Joule losses minimization theory. The second technique is an on-line one based on the minimization of copper losses, as this point appears to be particularly relevant for ship propulsion. The objective of these two techniques is to achieve ripple-free torque with minimum Joule losses. Firstly, the dynamic model of the 5-phase PMSM with trapezoidal back-EMF is given. Then detailed derivation of both control techniques and current reference extraction are presented. Finally, simulation and experimental results on a low-power laboratory test bench are presented and discussed.

Sintered zirconium carbide (C/Zr ≈ 0.95) was studied by pulsed electrical heating method with microsecond duration. Thermophysical properties such as Joule energy, heat of melting, the specific heat, and electrical resistance were measured in the temperature range of 2500–5000 K by this method for the first time. The steep increase of the specific heat just before melting may be associated with the formation of nonequilibrium pairs point Frenkel defects at high temperatures under fast heating. It was established that the melting of the carbide occurs in the temperature range: solidus—3450 K and liquidus—3850 K, that is close to the values presented in some equilibrium phase diagrams of the system Zr–C. This means that there is no shift of the phase transition points at the heating rates up to 108 K/s, and makes it possible to use this method for the study of high temperature behavior of the complex substances. The comparison of the data of measured properties with the literature data is provided.

In this paper, the concept of an annular thermoelectric heat pump (ATEHP) has been introduced. An exoreversible thermodynamic model of the ATEHP considering the Thomson effect in conjunction with Peltier, Joule and Fourier heat conduction has been investigated using exergy analysis. New expressions for dimensionless heating power, optimum current at the maximum energy, exergy efficiency conditions and dimensionless irreversibilities in the ATEHP are derived. The results show that the heating power, energy and exergy efficiency of the ATEHP are lower than the flat-plate thermoelectric heat pump. The effects of annular shape parameter (Sr = r2/r1), dimensionless temperature ratio (θ = Th/Tc) and the electrical contact resistances on the heating power, energy/exergy efficiency of an ATEHP have been studied. This study will help in the designing of actual ATEHP systems.

The environmental conditions that describe an ecosystem define the amount of energy available to the resident organisms and the amount of energy required to build biomass. Here, we quantify the amount of energy required to make biomass as a function of temperature, pressure, redox state, the sources of C, N and S, cell mass and the time that an organism requires to double or replace its biomass. Specifically, these energetics are calculated from 0 to 125 °C, 0.1 to 500 MPa and -0.38 to +0.86 V using CO2, acetate or CH4 for C, NO3(-) or NH4(+) for N and SO4(2-) or HS(-) for S. The amounts of energy associated with synthesizing the biomolecules that make up a cell, which varies over 39 kJ (g cell)(-1), are then used to compute energy-based yield coefficients for a vast range of environmental conditions. Taken together, environmental variables and the range of cell sizes leads to a ~4 orders of magnitude difference between the number of microbial cells that can be made from a Joule of Gibbs energy under the most (5.06 × 10(11) cells J(-1)) and least (5.21 × 10(7) cells J(-1)) ideal conditions. When doubling/replacement time is taken into account, the range of anabolism energies can expand even further.

The impacts of Joule’s dissipation and frictional heating on non-Newtonian ferrofluid flows past a bidirectionally stretching convective surface are investigated. We assumed that Fe3O4 nanoparticles are mixed with methanol. Both Casson and Williamson models are opted while formulating the basic flow equations. The impact of temperature dependent viscosity is accounted. The Joule heating and viscous dissipation impacts are also considered. Shooting and R.K. numerical procedures are used to solve the flow problem. Graphical and tabular illustrations are presented with a view of understanding the nature of flow and heat transfer for discrete values of flow parameters. It is worth to note that the thickness of velocity boundary layer of Casson fluid flow is greater than that of Williamson fluid flow. Also the presence of Joule and frictional heating leads to more heat energy to Casson fluid flow while compared to that of Williamson fluid. Heat transfer rate is better in Williamson fluid compared to that of Casson fluid.

We propose an approach that permits constructing an analytical solution of the problem of flow and heat transfer in a viscous compressible conducting medium near an infinite dielectric disk rotating in a homogeneous magnetic field. The influence of the magnetic field on the process of heat transfer near the disk surface has been investigated. It has been shown that Joule energy dissipation prevails over viscous dissipation at moderate magnetic fields.

As technology scales further, multicore and many-core processors emerge as an alternative to keep up with performance demands. However, because of power and thermal constraints, we are obliged to power off remarkable area of chip. Many innovative techniques have been presented to improve energy efficiency and maintain utilization at the highest level. In this paper, we discuss different models and methods of exploiting dark silicon, and by using dynamic voltage and frequency scaling in Amdahl's law and considering memory overheads, we attempt to decrease amount of dark silicon and improve performance and performance per watt/joule. We propose high-performance and energy-efficient multicore architectures for variety of parallelisms and memory-intensities in workloads. According to the results, by voltage scaling, for a highly parallel CPU-intensive workload, we reach improvements of approximately $$5.2{\times }$$5.2× and $$3.78{\times }$$3.78× in performance per watt and performance per joule, respectively, while about 27 % reduction of performance should be tolerated. For memory-intensive applications, a negligible change in speedup is detected by scaling, while performance per watt and performance per joule for both serial and parallel applications lead to around $$6{\times }$$6× enhancements.

In traditional hot stamping process, heating of the sheet by radiation heating occupies most of cycle time, which limits the application of hot stamping in automotive industry. Thus a faster heating method has great significance on the hot stamping. The conduction heating overcomes shortage of the radiation heating because of higher heating rate and greater energy efficiency. It attracts increasing attention in the application of heating blanks in hot stamping. In the present study, a movable conduction heating device on die was designed in terms of the Joule’s Law. Heating experiments of boron alloyed steel were performed using the developed device. Heating rate and uniform temperature region were investigated in the non-heat preservation condition (NHPC) and the heat preservation condition (HPC). The results revealed that in the HPC, the heating rate was improved by 13.1 °C/s. In addition, the length of the uniform temperature region was lengthened by 15 mm. It was demonstrated that the HPC was preferred. Furthermore, it was indicated that the mechanical properties of the blanks in uniform temperature region of the conduction heating were also superior to that of the radiation heating.

A three-dimensional closed-circuit numerical model of a thermoelectric generator (TEG) module has been constructed with COMSOL® Multiphysics to verify a module test system. The Seebeck, Peltier, and Thomson effects and Joule heating are included in the thermoelectric conversion model. The TEG model is employed to simulate the operation of a 16-leg TEG module based on bismuth telluride with temperature-dependent material properties. The module is mounted on a test platform, and simulated by combining the heat conduction process and thermoelectric conversion process. Simulation results are obtained for the terminal voltage, output power, heat flow, and efficiency as functions of the electric current; the results are compared with measurement data. The Joule and Thomson heats in all the thermoelectric legs, as functions of the electric current, are calculated by finite-element volume integration over the entire legs. The Peltier heat being pumped at the hot side and released at the cold side of the module are also presented in relation to the electric current. The energy balance relations between heat and electricity are verified to support the simulation.

In this paper a three-dimensional steady-state thermal model of the rotor of an induction motor is presented using finite element formulation and arch shaped elements in the r $$-$$ $$\uptheta $$ and z plane of the cylindrical co-ordinate system. Excepting for providing a more accurate representation of the problem, the proposed model can also reduce computing costs. The temperature rise in the motor is due to Joule’s losses in rotor windings and heat dissipation by air convection and solid conduction. Using these loss distributions as an input for finite element analysis, more accurate temperature distributions can be obtained. The model is applied to one squirrel cage induction motor of 7.5 kW rating. Temperature limits of copper in the rotor structure can be achieved by the reduction in overall energy losses with the proper design of a cooling system that results in an increase in the energy efficiency of the squirrel cage induction motor.

A set-reset all-optical flip-flop (SR-AOFF) based on semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) is proposed. Simulation results show that low switching energy in the femto joule range, the transition time of less than 20 ps, high stability and high extinction ratio (ER) of 30 dB can be achieved, while AOFF output is power insensitive approximately.

In the theory of heat of the first half of the nineteenth century, heat was a substance. Mayer and Joule contradicted this thesis but developed different concepts of heat. Heat was a force for Mayer and a motion for Joule. Both Mayer and Joule determined the mechanical equivalent of heat. This result was, however, justified in accordance with those concepts of heat. Mayer’s characterisation of force reappears in the very common textbook definition ‘energy cannot be created or destroyed but only transformed’ and his theory led to a phenomenological approach to energy. Joule and Thomson’s concept of heat led to a mechanistic approach to energy and to the common definition ‘energy is the capacity of doing work’. One and the same term ‘energy’ subsumed these two approaches. The problematic concept of energy, energy as a substance, appears then as a result of an eclectic development of the concept. Another approach, which appeared in the 1860s, is directly based on the mechanical equivalent of heat and can be characterized by the use of ‘principle of equivalence’ instead of ‘principle of energy conservation’. Unlike the others, this approach, which has been lost, poses no problems with the concept of energy. The problems with the energy concept as to the kind of phenomena dealt with in the present paper can, however, be overcome, as we shall see, in distinguishing between that which comes from experiments and that which is an interpretation of the experimental results within a conceptual framework.

A general energy equation of quasi-one-dimensional heat flow in a longitudinal thermoelement (TE) of a curved side that is subjected to an electric field and convection heat transfer on the curved surface is developed. The energy equation is solved for the temperature distribution in two cases; uniform cross-section TE and non-uniform cross-section TE. Analytical solutions for a uniform cross-section TE with uniform electrical and thermophysical properties are obtained, whereas numerical solutions are provided for a non-uniform cross-section TE. Two parameters playing a vital role in the thermal performance of the TE are identified: the heat resistance ratio (HRR) and the energy growing ratio (EGR). The HRR represents the ratio of the longitudinal conduction maximum thermal resistance to the lateral convection maximum thermal resistance. The EGR represents the ratio of Joule’s electrical heating to Fourier’s heat conduction. The effects of varying these two parameters, as well as the TE geometry, have been thoroughly investigated.

A uniform transient temperature field model of electrical contacts operation was found by analyzing the process of closing arc → constriction resistance Joule heat → breaking arc. Essential parameters of Ag/La2NiO4 electrical contact material for transient temperature field calculation were obtained through tests of electrical contact experimental instrument under 18 V DC in different currents, other correlation experiments, and calculation analysis. The finite element method was applied to solve the transient temperature field, and the features and distribution of the transient temperature field were obtained. The condition of material erosion and mass transfer can be forecasted by those calculation results. It is beneficial to research about the lifetime of Ag/La2NiO4 electrical material. The two curves of current with product of maximum molten pool volume and lifetime of molten pool for break arc and close arc crossed between 20 and 25 A. Those curves are related with the mass transfer curves. Because the mass transfer was directly affected by molten pool volume and molten pool lifetime, the direction of mass transfer can be forecasted. The direction of mass transfer began to change from anode to cathode after current was larger than 20 A. These are consistent with the experimental results.

In 1960, E. H. Brown defined a set of characteristic curves (also known as ideal curves) of pure fluids, along which some thermodynamic properties match those of an ideal gas. These curves are used for testing the extrapolation behaviour of equations of state. This work is revisited, and an elegant representation of the first-order characteristic curves as level curves of a master function is proposed. It is shown that Brown’s postulate—that these curves are unique and dome-shaped in a double-logarithmic p, T representation—may fail for fluids exhibiting a density anomaly. A careful study of the Amagat curve (Joule inversion curve) generated from the IAPWS-95 reference equation of state for water reveals the existence of an additional branch.

This paper reviews our previous theoretical studies and gives further insight into phonon scattering in 3D small nanotransistors using non-equilibrium Green function methodology. The focus is on very small gate-all-around nanowires with Si, GaAs or InGaAs cores. We have calculated phonon-limited mobility and transfer characteristics for a variety of cross-sections at low and high drain bias. The nanowire cross-sectional area is shown to have a significant impact on the phonon-limited mobility and on the current reduction. In a study of narrow Si nanowires we have examined the spatially resolved power dissipation and the validity of Joule’s law. Our results show that only a fraction of the power is dissipated inside the drain region even for a relatively large simulated length extension (approximately 30 nm). When considering large source regions in the simulation domain, at low gate bias, a slight cooling of the source is observed. We have also studied the impact of the real part of phonon scattering self-energy on a narrow nanowire transistor. This real part is usually neglected in nanotransistor simulation, whereas we compute its impact on current–voltage characteristic and mobility. At low gate bias, the imaginary part strongly underestimated the current and the mobility by 50 %. At high gate bias, the two mobilities are similar and the effect on the current is negligible.\ud \ud

Recently the so-called electropyroelectric technique for thermal characterization of liquids has been proposed (Ivanov et al., J. Phys. D: Appl. Phys. 43, 225501 (2010)). In this method a pyroelectric sensor, in good thermal contact with the investigated sample, is heated by passing an amplitude-modulated electrical current through the electrical contacts. As a result of the heat dissipated to the sample, the pyroelectric signal measured as a voltage drop across the electrical contacts changes in a periodical way. The amplitude and phase of this signal can be measured by lock-in detection as a function of the electrical current modulation frequency. Because the signal amplitude and phase depend on the thermal properties of the sample, these can be determined straightforwardly by fitting the experimental data to a theoretical model based on the solution of the heat diffusion equation with proper boundary conditions. In general, the experimental conditions are selected so that the thermal effusivity becomes the measured magnitude. The technique has the following handicap. As the result of heating and wear of the metal coating layers (previously etched to achieve a serpentine form) with time, their electrical resistance changes with time, so that the heat power dissipated by the Joule effect can vary, and thermal effusivity measurement can become inaccurate. To avoid this problem in this study, a method is proposed that allows maintaining stable the Joule dissipated power. An electronic circuit is designed whose stability and characteristics are investigated and discussed.

A phenomenological approach is proposed to identify some effects occurring within the structure of the microswitch conceived for radio frequency application. This microsystem is operated via a nonlinear electromechanical action imposed by the applied voltage. Unfortunately, it can be affected by residual stress, due to the microfabrication process, therefore axial and flexural behaviors are strongly coupled. This coupling increases the actuation voltage required to achieve the so-called “pull-in” condition. Moreover, temperature may strongly affect strain and stress distributions, respectively. Environmental temperature, internal dissipation of material, thermo-elastic and Joule effects play different roles on the microswitch flexural displacement. Sometimes buckling phenomenon evenly occurs. Literature show that all those issues make difficult an effective computation of “pull-in” and “pull-out” voltages or evenly distinguishing the origin of some failures detected in operation. Analysis, numerical methods and experiments are applied to an industrial test case to investigate step by step the RF-microswitch operation. Multiple electro-thermo-mechanical coupling is first modeled to have a preliminary and comprehensive description of the microswitch behavior and of its reliability. “Pull-in” and “pull-out” tests are then performed to validate the proposed models and to find suitable criteria to design the RF-MEMS.

Si-doped GaAs nanowires (NWs) were grown on (111)Si substrate by MBE-VLS method. The electrical characteristics of the GaAs NWs were measured. A joule heater was arranged near the tip of NW for making the gradient of substrate temperature. The obtained Seebeck coefficient of the GaAs NW increases linearly with a rise in temperature. The thermoelectric power of the Si doped GaAs NW was determined by the hole diffusion. It was estimated that the hole density in the Si-doped GaAs NW at room temperature was 5.9×1018 cm-3 from the slope of the temperature dependence of the Seebeck coefficient in the Si-doped GaAs NW. At room temperature, the Seebeck coefficient, thermoelectric power factor, and thermoelectric figure of merit (ZT) were 429 μV/K, 271μW/mK2, and 1.5×10-3, respectively.

Although ocean crude-oil spill accidents did not frequently happened in the past, it really caused great damage to the marine ecosystem once it happened. Because of the spreading and weathering, crude-oil spill usually covers a large area of water surface and its viscosity is very high, which brings human great trouble to clean it up. Dispersant and in-situ burning were frequently used in the past crude-oil spill accidents, but these two methods suffered from the drawbacks including being toxic to marine lives, causing air pollution, disability of recovering the crude oil. Oil skimmers could recovery the oils, but their handling capacities are rather limited. Recently, porous hydrophobic and oleophilic materials (PHOM) have been demonstrated as low-cost, efficient and ecofriendly materials for the oil spill cleanup [1]. Nevertheless, their poor absorption speed to viscous oil spill hinders their practical application.

The results of research, carried out at the Mendeleev All-Russia Research Institute of Metrology in 2007–2010 to improve the standard base of Russia, are presented. This research resulted in the design and approval of a new generation of equipment, unique in the world, as the State Primary Standard of the units of heat of combustion - the joule, the specific heat of combustion - the joule per kilogram and the volume heat of combustion - the joule per cubic meter. The composition of the standard and its metrological characteristics are considered.

In this study, the magnetohydrodynamics (MHD) natural convection heat transfer with Joule and viscous heating effects inside an iso-flux porous medium-filled inclined rectangular enclosure is studied numerically. An iso-heat flux is applied for heating and cooling the two opposing walls of the enclosure while the other walls are adiabatic. The Forchheimer extension of Darcy-Oberbeck-Boussinesq and energy equations is transformed into a dimensionless form using a set of suitable variables instead of a finite difference scheme. The governing parameters are the magnetic influence number, the modified Rayleigh number, the inclination angle, and the aspect ratio of the enclosure. The results show that viscous and Joule heating effects decrease heat transfer rates.

We have studied thermal gradients in thin Cu and AlMn wires, both experimentally and theoretically. In the experiments, the wires were Joule heated non-uniformly at sub-Kelvin temperatures, and the resulting temperature gradients were measured using normal metal–insulator–superconducting tunnel junctions. The data clearly shows that even in reasonably well-conducting thin wires with a short (~10 μm) non-heated portion, significant temperature differences can form. In most cases, the measurements agree well with a model which includes electron–phonon interaction and electronic thermal conductivity by the Wiedemann–Franz law.

Variational analysis of LCVD rod growth was made possible by a new axial convection enhanced micro-reactor design that lent itself to accurate in-process measurements of growth rate and position inside the growth region. The methodology follows a typical design of experiments approach where the effect of small perturbations to process parameters are measured in real-time. The findings are rather startling. They point to a growth rate that is not symmetrical with respect to the focal plane. In fact, the peak growth rate is consistently recorded well in front of the focal plane, at a distance one order of magnitude greater than the Raleigh range, decreases rapidly afterward, steadies across the focus, and then decreases slowly. A measure of energetic efficiency can be derived that shows a rapid decay of the amount of material deposited per Joule. A central assumption to this analysis is that growth occurs in the kinetic domain and that was confirmed experimentally. The reason for the great variability and asymmetry observed are still unknown. However, corroboration of our results would throw into question a large body of published LCVD measurements as they would have to account for the wide variability of the measured quantities within the growth region.

We have studied thermal gradients in thin Cu and AlMn wires, both experimentally and theoretically. In the experiments, the wires were Joule heated non-uniformly at sub-Kelvin temperatures, and the resulting temperature gradients were measured using normal metal-insulator-superconducting tunnel junctions. The data clearly shows that even in reasonably well conducting thin wires with a short ($\sim 10 \mu$m) non-heated portion, significant temperature differences can form. In most cases, the measurements agree well with a model which includes electron-phonon interaction and electronic thermal conductivity by the Wiedemann-Franz law., Comment: J. Low Temp. Phys. in press

With the availability of off-the-shelf commercial ultrafast lasers, a small revolution in materials research is underway, as it is now possible to use these tools without being an expert in the development of the tools themselves. Lasers with short-duration optical pulses—in the sub-picosecond (less than one-trillionth of a second) range—are finding a variety of applications, from basic research on fast processes in materials to new methods for microfabrication by direct writing. A huge range of pulse energies are being used in these applications, from less than 1 nJ (a billionth of a joule) to many joules.

A compact spark pre-ionized pulser sustainer TE-CO2 laser that can produce an output energy of one joule with an overall efficiency of 12.4% is presented. Optical pulses have durations of 7.15 µs FWHM. Here, the laser uses all solid-state excitation (ASSE) circuit and the discharge formed between two uniform field electrodes placed 1.5 cm apart ultimately leads to a discharge volume of 50 cm × 1.5 cm × 1.5 cm