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L’objectiu d’aquest projecte és l’anàlisi del procés de fabricació d’un tipus de resistències domèstiques per tal de reduir la quantitat de peces defectuoses obtingudes al llarg del conjunt de fases que intervenen. La iniciativa d’aprofundir en aquest tema comença a l’hora d’analitzar les ordres de fabricació que s’entreguen diàriament, on es detecta que hi ha una gran quantitat de peces que, un cop sortides de la última fase de fabricació de la màquina, no compleixen al 100% els criteris de qualitat i no són aptes per servir al client final. Aquestes peces, o bé es poden recuperar a través d’un condicionament mecànic, afegint processos addicionals que fan encarir els costos de fabricació, o bé directament es classifiquen com a defectuoses. A partir de les dades obtingudes al llarg dels últims dos anys, l’anàlisi minuciós del procés fase a fase i mitjançant l’aplicació d’un conjunt d’eines de Lean Manufacturing, s’han trobat les principals causes que provoquen aquesta situació i s’han plantejat propostes de millora a implementar, amb la finalitat d’aconseguir millorar la disponibilitat del producte final, a través de l’augment de la quantitat de peces bones obtingudes a la primera sense haver de forçar a la màquina a fabricar més peces de les inicialment planificades, mitjançant la modificació de paràmetres. Per tal de revertir la situació actual i obtenir una millora dels indicadors de qualitat, les propostes realitzades es focalitzen en tres dels possibles defectes que es poden presentar a l’acabat del producte final: per una banda, en forma d’optimització de les condicions de les eines i màquines i del seu manteniment, i per una altra banda, implementant directament una nova fase a la màquina que executi un condicionament que actualment es realitza manualment, de manera addicional. S’ha realitzat una valoració econòmica en la qual es pressuposta el cost de les millores, la viabilitat del projecte (impacte econòmic) i rendibilitat. El objetivo de este proyecto es el análisis del proceso de fabricación de un tipo de resistencias domésticas con el fin de reducir la cantidad de piezas defectuosas obtenidas a lo largo del conjunto de fases que intervienen. La iniciativa de profundizar en este tema empieza a la hora de analizar las órdenes de fabricación que se entregan diariamente, donde se detecta que hay una gran cantidad de piezas que, una vez salidas de la última fase de fabricación de la máquina, no cumplen al 100% los criterios de calidad y no son aptos para servir al cliente final. Estas piezas, o bien se pueden recuperar a través de un acondicionamiento mecánico, añadiendo procesos adicionales que hacen encarecer los costes de fabricación, o bien directamente se clasifican como defectuosas. A partir de los datos obtenidos a lo largo de los últimos dos años, el análisis minucioso del proceso fase a fase y mediante la aplicación de un conjunto de herramientas de Lean Manufacturing, se han encontrado las principales causas que provocan esta situación y se han planteado propuestas de mejora a implementar, con el fin de conseguir mejorar la disponibilidad del producto final, a través del aumento de la cantidad de piezas buenas obtenidas a la primera sin tener que forzar a la máquina a fabricar más p iezas de las inicialmente planificadas, mediante la modificación de parámetros. Con el fin de revertir la situación actual y obtener una mejora de los indicadores de calidad, las propuestas realizadas se focalizan en tres de los posibles defectos que pueden presentar el acabado del producto final: por un lado, en forma de optimización de las condiciones de las herramientas y máquinas y de su mantenimiento y, por otro lado, implementando directamente una nueva fase a la máquina que ejecute un acondicionamiento que actualmente se realiza manualmente, de manera adicional. Se ha realizado una valoración económica en la cual se presupuesta el coste de las mejoras, la viabilidad del proyecto i rendibilid. The aim of this project is the analysis of the manufacturing process of a type of domestic resistances in order to reduce the number of defective parts obtained throughout the set of phases involved. The initiative to delve deeper into this subject begins when analyzing the manufacturing orders that are delivered daily, where it is detected that there are a large number of parts that, once they come out of the last phase of machine manufacturing, do not meet the 100% quality criteria and are not suitable to serve the end customer. These parts can either be recovered through mechanical conditioning, adding additional processes that make manufacturing costs more expensive, or they are directly classified as defective. Based on the data obtained over the last two years, the detailed analysis of the process phase by phase and through the application of a set of Lean Manufacturing tools, the main causes of this situation have been found and the main causes of this situation have been raised. improvement proposals to be implemented, in order to improve the availability of the final product, by increasing the number of good parts obtained the first time without having to force the machine to manufacture more parts of those initially planned, by modifying parameters. In order to reverse the current situation and obtain an improvement in quality indicators, the proposals made are focused on three of the possible defects that the finish of the final product may present: on the one hand, in the form of optimization of the conditions of the tools and machines and their maintenance and, on the other hand, directly implementing a new phase to the machine that performs conditioning that is currently done manually, additionally. An economic valuation has been carried out in which the cost of the improvements is budgeted, the viability of the project in the form of economic impact and the time necessary for this investment, to be profitable.

Worldwide Interoperability for Microwave Access (WiMAX) is a Broadband Wireless Access (BWA) technology that has high speed and wide access for multimedia communication. The reception of quality video or voice packets at the receiver is related to how efficient the energy consumption is sent by the Subscriber Station (SS). The more video or voice packets that are sent, the more energy consumption is needed. One way to calculate energy consumption at a WiMAX subscriber station is by using mathematical modeling. This final project is modeling energy consumption in WiMAX. From the simulation, it is found that the change in the bit rate affects the energy consumption of the subscriber station. Through simulation, training data is generated to obtain a mathematical model.The mathematical model contains the components of the state duration and the level of energy consumption. Mathematical models are then used to predict energy consumption in WiMAX. The model is tested through the generation of test data. The test results through simulation showthe percentage deviation of the average energy consumption of training data with mathematical modeling on average is 0.180%. Meanwhile, the energy consumption of test data and mathematical models has an average deviation of 0.187% and 0.191%. The least energy consumption is generated when the MAC Initialization state (state i0) is 0.001 Joule, while the highest energy consumption is the Uplink Frame state (state i14) of 101.017226 Joule.

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.

Through energy efficiency and demand flexibility, buildings can play a prominent role in mitigating the urgent and severe consequences associated with a changing climate. In this issue of Joule, the paper by Langevin et al. provides clear insight into the magnitude of impact buildings can have.

The use of electric power is significant to supply water pumps which are usually obtained from PLN electricity. The utilization of electricity from new renewable energy such as solar panel electricity and water turbines has not been used too much to cultivate hydroponic plants. Therefore, combining electric power (hybrid) between solar cells and water turbines is needed to supply electricity on hydroponic technology in conserving electrical energy for the future. Based on these problems, this study conducted various tests to create a design that could be used for energy use in hydroponic plants. The method used includes electrical and systematic design. The steps taken include the stage of literature study, designing, manufacturing hardware, integrating the system, and testing and analyzing the system. These theories can discover solar panels, solar chargers, battery endurance, thief joule circuits, and water turbines. This study uses several tests, including solar panels, solar chargers, battery endurance, thief joule series, and water turbines. Solar panels function to capture sunlight, solar chargers to store electrical voltage to batteries, battery endurance functions to find out how many batteries can store electricity, a series of thief joules to increase voltage, and water turbines to produce voltage. From all data tests, solar panels and water turbines are a source of voltage that the battery will store via a solar charger, and then from the battery, it will be supplied to the hydroponic circuit as a source of voltage.

The article presents a study of the origin of extra harmonics in the frequency spectrum of thermocouple output signal when being heated by sinusoidal waveform current. It is natural to have the first harmonic, which arises according to Ohm’s law, as a product of current and the total resistance of thermocouple and junction conductors, as well as the Peltier, Thomson effects, and the presence of the second harmonic, which is caused by a heating of junction and thermocouple conductors. The fact that third and higher harmonics arise when the resistance of conductors and junction is thermally dependent was identified. The analytical dependence of the resulting voltage across the thermocouple terminals as a function of the total resistance of conductors and junction, and the voltages due to the effects of Joule, Seebeck, Peltier and Thomson, is established. Based on the analysis of the obtained function and experimentally obtained voltage spectra across the terminal of the thermocouple, an assumption was made about the nature of the voltage spectrum that heats thermally dependent wires of the thermocouple. Recommendations are given to reduce the influence of the first, third and higher harmonics, which are uninformative, and to separate the voltage of the second informative harmonic, which is used to get frequency response of the thermocouple. Keywords: frequency response; thermocouple; EMF; spectrum; thermally dependent resistance; voltage

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.

Twisted and coiled polymer muscles (TCPM) are inexpensive, light weight and simple artificial muscles that are introduced recently. For implementation of this muscle as a linear controllable actuator, we need an open loop or closed loop control system. In this paper we proposed a new artificial stepper tensile actuator based on joule-heated TCPM (we name it “stepper TCPM”) that will be used as a stepping straight actuator and can be control via an open loop control system. There are not any sensors in the proposed actuator, so the actuator can be used in an open loop control system for stepping linear movements. This stepper actuator consists of some serial TCPM string with some individual heater isolated wires that twisted around the fiber of each TCPM. The maximum displacement of each TCPM is double of the previous TCPM, therefore the full set or reset of current of these wires result full contraction of each TCPM and stepping displacement control of stepper TCPM. Our experiment shows that we can control step by step displacement of proposed actuator without any sensor or closed loop control system (similar to common stepper motor but in straight motion). Proposed actuator is applicable in low cost and low weight stepping movement mechanism.

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.

Electricity is an efficient form of energy, and the growing interest in electricity-assisted manufacturing is motivated by its inherent energy saving and reduced environmental impact. Beyond this, Electromagnetic Processing of Materials (EPM) allows the fabrication of materials with new compositions, metastable phases and nanograined microstructures that cannot be obtained using conventional heating processes using furnaces. This review covers EPM for the manufacture of ceramic and metal bulk components, with a specific focus on the effects of electric fields and electromagnetic radiations on processing in a wide spectrum of frequencies ranging from DC (f=0 Hz) to visible light (f= 1014–1015 Hz). The manuscript is divided into two parts. The first part provides a comprehensive overview of the interactions between matter and electric field/current, including heating phenomena (resistive Joule, induction, dielectric heating, electric arcs) and athermal effects (electromigration, electroplasticity, electrochemical reactions, ponderomotive force and others). The second part is focused on the technological application of the techniques, covering heat treatments, joining, sintering and forming. Seven distinct physical phenomena are involved in EPM: resistive Joule and induction heating, electrochemical reactions, electroplasticity, electric arcs and electromagnetic heating based on radio and microwave frequencies (mainly used for heating dielectric materials; i.e., dielectric heating) or on the IR/visible light (IR heating and lasers).

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.

Purpose. Research initiated by revealing the paradox of disturbed energy balance based on the position of the virial theorem and studying examples of the Van de Graaf generator, a capacitor containing a ferroelectric, and a heat pump capable of providing an energy conversion factor greater than 100%, as well as an idealized theoretical known as the Maxwell demon, showed the possibility of increasing the efficiency of converting current energy into Joule heat. Methodology. The results are verified by comparing the relative efficiency of the conversion of current energy into heat in the oscillatory, critical and aperiodic modes of the transient process in a series oscillating circuit. Mathematical modeling in a wide range of parameter changes has shown the advantage of using the aperiodic transient mode of a series oscillating circuit to convert current energy into heat, compared to the power supply of an electric heating system, which is based on the established method. Experimental tests of the experimental sample fully confirm the qualitative results of mathematical modeling. Results. An achievable limit level of conversion efficiency in the active resistance of energy accumulated by inductance and capacitance according to the virial theorem is established. Originality. For the first time, the application of the aperiodic transient mode in a series oscillatory circuit is proposed in order to convert the energy of current to Joule heat. Practical value. As a practical result, a method of converting current energy into pulse energy has been developed, which implements the algorithm of simultaneous energy accumulation by inductance and capacitance, and its simultaneous conversion in a series oscillating circuit, for which a patent has been obtained. Possibilities of application of the developed method for the purpose of induction heating of metals by Foucault currents as replacement of a method of shock excitation of fluctuations are studied. To this end, the conductivity of metals, which causes the flow of Foucault currents, should be considered as the introduction of equivalent active resistance in the oscillating circuit. The introduction of the method will not require changes in the process equipment, except for the power supply scheme, and should eliminate the fundamental disadvantage of the method of shock excitation of powerful oscillations, which is low efficiency.

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.

We consider a Radio Frequency (RF)-charging network where sensor devices harvest energy from a solar-powered Hybrid Access Point (HAP) and transmit their data to the HAP. We aim to optimize the power allocation of both the HAP and devices to maximize their Energy Efficiency (EE), which is defined as the total received data (in bits) for each Joule of consumed energy. Unlike prior works, we consider the case where both the HAP and devices have causal knowledge of channel state information and their energy arrival process. We model the power allocation problem as a Two-layer Markov Decision Process (TMDP), where the first layer corresponds to the HAP and the second layer consists of devices. We then outline a novel, decentralized Q-Learning (QL) solution that employs linear function approximation to represent the large state space. The simulation results show that when the HAP and devices employ our solution, their EE is orders of magnitude higher than competing policies.

The temperature dependences of the tension and stiffness of actively contracting single fibers of the rabbit slow muscle (m. soleus) were studied using the Joule temperature jump. Differences in the characteristics of the fibers of the rabbit fast (m. psoas) and slow (m. soleus) muscles were shown; apparently, they were caused by differences in the kinetics of the myosin head cycle.

In the October issue of Joule, Grant et al. explore how uncertainties in three CDR pathways (BECCS, DACCS, and afforestation/reforestation) can be incorporated into integrated assessment models, resulting in an additional 10 gigatons of CO2e requiring mitigation by 2030. This finding underscores the importance of accelerating CDR research, design, and development.

Wearable biosensors can monitor biological vital signs of health continuously but require sustainable power technology to realize a paradigm shift towards connected healthcare anytime, anywhere. A recent article in Joule ( Yin et al. ) reports a fingertip-based self-powered wearable device that can harvest sustainable bioenergy more efficiently than previous technologies.

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.

The article demonstrates the electrothermomechanical behavior of thin-film for two different shape memory alloys by the Finite Element analysis method. The effect of varying input currents and different thin film thicknesses on the stress, temperature, and deformation is analyzed. Comparing the results obtained for the two alloys concludes that Ni40-Ti50-Cu10 thin film is a better choice for actuator applications. The results presented can assist in preparing a predictive model, which further helps forecast the corresponding values of electric current and film thickness for the desired temperature and displacement. Controlling the desired temperature based on the inputs provided can be a better method of programming and actuating the SMA thin film using Joule’s heating mechanism.

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 article analyzes the Mathematical Model of The Self-Baking Electrode which is defined as basic. Its advantages and disadvantages are determined. Criterias for creating more advanced mathematical model for equalizing the thermal field of the Electrode are proposed. The problem of calculating the thermal field is solved by the the method of elementary heat balances of electrode. For this goal the simulated area is divided into annular (cylindrical) elements along the radius and height of the electrode.The calculation of the temperature field of the electrode is carried out in two stages: I – with boundary conditions and currents for the parts of the electrode facing to the center of the smelting furnace; II – with boundary conditions and currents for the parts of the electrode facing to the lining. The mathematical model takes into account an effect of the ribs and the hood on the distribution of electric current and Joule’s Heat over the cross section of the Electrode. In case heating ferromagnetic materials under impact of an electromagnetic field, the magnetic permeability at first decreases relatively slowly, and then droping down sharply as a certain temperature (Curie Point) is reached. The material loses its magnetic properties completely and goes into into a paramagnetic state. The value of the electrode current changes according to the graph from the starting value to the working value and then remains constant. The current density of the electrode along the radius is unequal due to the action of the surface effect, as well as due to existence of a metal hood and ribs, the electrical conductivity of which is higher than conductivity of special carbon paste. The goal of the work is to create modern mathematical model of the secondary current network of electric smelting furnace which could improve baking conditions of the Electrode and to reach the state of its temperature field to equable. This would create a stable mode of operation of the furnace.The paper analyzes the main features of the mathematical model of the secondary network of the smelting furnace, identifies the stages of development and formulates the main assumptionssimplifications that could be accepted wile creating this model.

Korean old residential apartments built over many decades were constructed without proper energy efficiency measures. This makes the energy performance of existing buildings to be very poor when compared with the energy performance of new buildings. This study presents the use of a 12 years gas consumption data to evaluate the energy performance of an existing residential building in Korea by carrying out Measurement and Verification (M&V) analysis using RETScreen Expert software after building retrofit. From the analysis, a total of 249 Giga Joules (GJ) of Liquefied Natural Gas (LNG) was consumed at the rate of 0.17 GJ/day on an average from the year 2011 to 2014 with the peak consumption in the year 2013 costing the occupant a sum of $5,401. Also, the net energy savings was 64GJ as of June 2019 after the installation of an Energy Conservation Measures (ECMs) with the highest between the year 2016 and 2018. An energy forecast for the year 2020 indicates that 2.71 (tCO2) GHG emissions will be reduced as a result of the energy that will be saved from the 54 Giga Joule (GJ) fuel consumed. Finally, energy efficiency was attained and this reduced the resident doubt on the benefits of energy efficiency measures.

Acid-stable electrocatalysts for water oxidation with sufficiently high activity are essential for their scalable utilization in commercial proton exchange membranes-based electrolyzers. Recently in Joule, Ge and colleagues reported the activation of localized lattice-oxygen redox for highly active and durable oxygen evolution reaction in acidic electrolytes.

Achieving stable high-efficiency single-component devices is a challenging problem in the field of organic photovoltaics. Recently in Joule, Min and co-workers reported a single-component organic solar cell using a conjugated donor-acceptor block copolymer (PBDB-T-b-PYT); a remarkable efficiency of 11.32% was realized with impressive photostability and storage stability.

High-throughput experimentation platforms and machine learning have shown preliminary success in materials research acceleration. Recently in Joule, Du, Brabec, and colleagues showed the potential of using a robotic platform to optimize organic photovoltaics (OPV) materials and devices. With a short experimental time of 70 h, it was demonstrated to achieve a power conversion efficiency of 14% and a photostability duration of 50 h.

Expanded deployment of renewable energy technologies can help society mitigate climate change. However, solar and wind energy resources are inherently variable. In this issue of Joule, Hunter and colleagues quantitatively compare a diverse set of energy storage and backup power technologies that can help variable energy resources meet demand. They estimate current technology costs, consider improvement potential, and approximate the uncertainties.

Renewable energy facilitates emission reductions, but its deployment also presents challenges. Recently in Joule, Cole et al. examined barriers to establishing a 100% renewable energy power system in the United States, but land-use-change impacts of renewable energy deployment on biodiversity conservation were unexplored and warrant interdisciplinary investigation.

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.

Neural processing units (NPUs) are becoming an integral part in all modern computing systems due to their substantial role in accelerating neural networks (NNs). The significant improvements in cost-energy-performance stem from the massive array of multiply accumulate (MAC) units that remarkably boosts the throughput of NN inference. In this work, we are the first to investigate the thermal challenges that NPUs bring, revealing how MAC arrays, which form the heart of any NPU, impose serious thermal bottlenecks to on-chip systems due to their excessive power densities. For the first time, we explore: 1) the effectiveness of precision scaling and frequency scaling (FS) in temperature reductions and 2) how advanced on-chip cooling using superlattice thin-film thermoelectric (TE) open doors for new tradeoffs between temperature, throughput, cooling cost, and inference accuracy in NPU chips. Our work unveils that hybrid thermal management , which composes different means to reduce the NPU temperature, is a key. To achieve that, we propose and implement PFS-TE technique that couples precision and FS together with superlattice TE cooling for effective NPU thermal management. Using commercial signoff tools, we obtain accurate power and timing analysis of MAC arrays after a full-chip design is performed based on 14-nm Intel FinFET technology. Then, multiphysics simulations using finite-element methods are carried out for accurate heat simulations in the presence and absence of on-chip cooling. Afterward, comprehensive design-space exploration is presented to demonstrate the Pareto frontier and the existing tradeoffs between temperature reductions, power overheads due to cooling, throughput, and inference accuracy. Using a wide range of NNs trained for image classification, experimental results demonstrate that our novel NPU thermal management increases the inference efficiency (TOPS/Joule) by $1.33\times $ , $1.87\times $ , and $2\times $ under different temperature constraints; 105 °C, 85 °C, and 70 °C, respectively, while the average accuracy drops merely from 89.0% to 85.5%.

The high-efficiency catalysts for the oxidative removal of volatile organic compounds (VOCs) as air pollutants are in urgent need. Because of the extremely low concentration of VOCs, very high intrinsic activity at low temperatures is required for the catalyst or the temperature has to be elevated, which causes unaffordable energy consumption. Here, a mesoporous three-dimensional-carbon-monolith (3DCM) supported Ag-Co3O4 bimetallic catalyst is fabricated for the catalytic removal of formaldehyde. Enabled by the excellent Joule-heating property of 3DCM, the catalyst can be precisely heated without the need to heat the largely excessive air and surroundings. By this means, the energy consumption of the whole device can be drastically reduced by 87%. As a proof-of-concept demonstration, in the presence of constant emission, the formaldehyde concentration can be reduced from 4 ppm to 600 ppb after 10 h reaction in a 2 m3 gastight chamber. The strategy here suggests a promising technology to eliminate VOCs efficiently, fast-responsively and energy-savingly.

In 1840, James Prescott Joule submitted to the Royal Society a paper describing experimental research on the heat produced by electric currents in metallic conductors, and inferring that the effect was proportional to the resistance of the conductors and to the square of the intensity of the current. Only an abstract of this paper was published in the Proceedings of the Royal Society , although a full paper with a similar title was printed in the Philosophical Magazine in 1841. Several authors have assumed that the content of the 1841 publication was the same as the rejected 1840 paper; however, the unpublished manuscript has been found within the archives of the Royal Society and is published here for the first time, along with a detailed analysis and comparison with the 1841 paper. The unpublished version is much shorter, and is different in certain respects from the published article. A detailed comparison throws light on several shortcomings of the unpublished version. The present work also studies the assessment of Joule's paper by the Royal Society, and elucidates the roles of Peter Roget and Samuel Christie in this connection.

The revised International System of Units has been implemented on May 20, 2019, and now, the Kibble/joule balance can be used to achieve the traceability of mass to the Planck constant. In principle, the Kibble/joule balance can be operated in three measurement schemes, in which the one-mode one-measurement phase (OMOP) scheme has obvious advantages over the other two schemes. The OMOP scheme was first proposed and tried in the Kibble balance, but due to the mutual interference between weighing and velocity measurements, the achieved mass/Planck constant measurement uncertainty did not match the goal of $5 \, \times \,10^{-8}$ . However, the mentioned interference can be well suppressed in the joule balance based on its quasi-static measurement characteristic. Therefore, the feasibility of the OMOP joule balance is analyzed in this article, and the measurement sequence is introduced in detail. Three factors involved in the OMOP joule balance that may affect the final mass measurement uncertainty are analyzed and demonstrated, i.e., the consistency of the two independent coils of the bifilar coil, the current effect of the special coil system, and the performance of the improved flux linkage difference measurement system. Besides, it is found that the stability of excitation current decreases significantly due to the movement of the magnet system, but the theoretical analysis shows that this does not affect the measurement result of the OMOP joule balance.

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.

Jyotirmoy Mandal completed his PhD in Applied Physics at Columbia University in the City of New York and is currently a Schmidt Science Fellow and a postdoctoral researcher at University of California, Los Angeles. His research interests include low-cost optical designs for radiative cooling and solar heating, with a focus on applications in developing countries. Yuan Yang is an associate professor in the Department of Applied Physics and Applied Mathematics at Columbia University in the City of New York. His research interests include electrochemical energy storage and thermal energy management. Dr. Yang has published over 70 peer-reviewed journal articles, including in leading journals such as Science, Proceedings of the National Academy of Sciences, Advanced Materials, and Joule. Nanfang Yu is an associate professor in the Department of Applied Physics and Applied Mathematics at Columbia University in the City of New York. His research interests include mid-infrared and far-infrared optics, metamaterials, biophotonics, and biologically inspired flat optics. Dr. Yu’s research has been published in leading journals like Science, Nature Materials, Nature Nanotechnology, and Joule. Aaswath P. Raman is an assistant professor of Materials Science and Engineering at the University of California, Los Angeles (UCLA). He is also co-founder and chief scientific officer of SkyCool Systems, a startup commercializing radiative cooling technologies. Dr. Raman’s research interests include nanophotonics, metamaterials, radiative heat transfer, and energy applications, including radiative cooling. His works have been published in leading journals such as Nature, Nature Energy, Physical Review Letters, and Joule.

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.

Organic-inorganic heterojunction perovskite solar cell (PSC) is promising for low-cost and high-performance photovoltaics. To further promote the performance of PSCs, understanding and controlling the underneath photoconversion mechanisms are highly necessary. Here, we present a comprehensive opto-electro-thermal (OET) study on the heterojunction PSCs by quantitatively addressing the coupled optical, carrier transport, and thermodynamic behaviors within the device. With achieving a good agreement with the experiment, we theoretically explore the thermodynamic mechanisms involving the energy conversions and focus especially on the origins of the various energy losses in PSCs. We summarize six categories of microscopic heat conversion processes in the heterojunction PSC, where the Joule and Peltier heats can be defined as the intrinsic losses in PSCs. Moreover, we also discuss the possible manipulation methods to decrease the energy losses, for example, by tailoring the doping concentration and energy-level alignment. An exemplified OET optimization is also presented, which predicts that the PCE of the fabricated PSC can be enhanced from 21.37% to 23.84%.

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.

In 2017, the second generation of the Joule balance achieved a measurement uncertainty of $2.4 \times 10^{-7}$ . The main source of the uncertainty is identified as the effect of the external field, resulting in $1.7 \times 10^{-7}$ in the uncertainty budget. Hence, two solutions are proposed in the Joule balance to eliminate the effect of the external field, i.e., the magnetic shielding and compensation coils. This paper first gives an overview of the constructions of the shield and the compensation coils. Then, the flux linkage difference of the external field is measured under different conditions. Last, the effect of the two solutions is verified through the experiments. Based on the measurement results, it can be found that the uncertainty resulting from the effect of the external field in the Joule balance will be reduced to $1.4 \times 10^{-8}$ when the two solutions are applied.

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.