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The energy transported by the electric current that circulates a thermoelectric element (TE) varies with position due to the Joule and Thomson effects. The Thomson effect may enhance or compensate the Joule effect. A method for measuring the Thomson coefficient of a TE is presented. This method is based on the total compensation of the Joule and Thomson effects. The electric current then flows without delivering power to the TE or absorbing power from it. For a TE, the global Thomson/Joule compensation ratio Φ ¯ T / J is defined as the ratio of the power absorbed by the current due to the Thomson effect and the power delivered by the current to the TE due to the Joule effect. It can be expressed as Φ ¯ T / J = I 0 / I , where I is the electric current and I 0 is the zero-power current, a quantity that is proportional to the average Thomson coefficient. When I = I 0 , the Thomson effect exactly compensates the Joule effect and the net power delivered by the current to the TE is zero. Since the power delivered by the current is related to the temperature distribution, temperature measurements for currents around I 0 can be used as the basis for a measurement technique of the Thomson coefficient. With varying current, the difference between the temperature at the center of the TE and the mean temperature between its extremes reverses its sign at the zero-power current, I = I 0 . This observation suggests the possibility of measuring the Thomson coefficient, but a quantitative analysis is needed. With calculations using the constant transport coefficients model for B i 2 T e 0.94 S e 0.06 3   and B i 0.25 S b 0.75 2 T e 3 , it is theoretically shown that a null temperature detector with a sensitivity of the order of 1 mK allows for the accurate determination of the Thomson coefficient. [ABSTRACT FROM AUTHOR]

Electrical contacts are important circuit components with diverse industrial applications, and their failure can lead to multiple unwanted effects. Hence, the behavior of electrical contacts is a widely studied topic in the scientific literature based on various approaches, tools, and techniques. The present study proposes a new approach to numerical modeling and simulation based on the Holm contact theory, aiming to study the dependence between the electric potential and the temperature within an electrical contact. Structured in five sections, the research was conducted using COMSOL Multiphysics software (version 5.3) and its solid-state mechanics, electric current, and heat transfer modules in order to highlight contact behavior from mechanical, electrical and thermal points of view: the von Mises stress, contact force, electric field amplitude, variation of the electrical potential along the current path, temperature gradient, and dependence of temperature along the contact elements edges were obtained by simulation, and are graphically represented. The results show that the temperature increase follows a parabolic curve, and that for values higher than 4 mV of voltage drop, the temperature of the contact increases to 79.25 degrees (and up to 123.81 degrees for 5 mV) over the ambient temperature, thus the integrity of insulation can be compromised. These values are close (10–12%) to the analytically calculated ones, and also in line with research assessed in the literature review. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model aimed at comprehensively understanding the thermal processes associated with arc erosion of closed electrical contacts triggered by the instantaneous explosion of micro-asperities including Thomson effect and Joule heat source. The phenomenon involves vaporization and liquid zones, and the temperature distribution is governed by a generalized heat equation, accounting for the heating effect due to current flow in temperature gradients and effect of heat source. The proposed model allows for a nuanced analysis of the thermal dynamics, shedding light on the complex phenomena involved in arc erosion. The proposed method in this paper employs similarity transformation techniques to effectively reduce the complexity of the problem, transforming it into a set of manageable ordinary differential equations. The study establishes the existence and uniqueness of the solution through rigorous analysis. The behavior of the solution of the problem is successfully considered for special cases of Thomson and thermal coefficients. By leveraging similarity transformations, the paper offers a powerful approach for unraveling the intricacies of the thermal processes in arc erosion of closed electrical contacts, providing valuable insights into the phenomena associated with current-carrying heating in the presence of temperature gradients.

Objective: This study investigates the influence of the Thomson effect on the behavior of a diffusive magneto-thermoelastic medium with initial stress and the dual-phase-lag (DPL) model. Methods: The normal mode analysis is utilized for solving the problem. The copper material was chosen for numerical assessments. The results are presented graphically for various physical quantities. Results: A comparison is made between the DPL model and the Lord and Shulman (L-S) theory, both in the absence and presence of the Thomson effect parameter as well as at two different values for the phase lag of heat flux. Conclusions: The findings provide insights into the impact of the Thomson effect on the behavior of the magneto thermoelastic medium, highlighting the differences between the DPL model and the L-S theory in different scenarios. This type of work has many applications in rock mechanics, geophysics, and petroleum industries. This work may be helpful for those researchers who are working in material science, smart materials, and new material designers. [ABSTRACT FROM AUTHOR]

Electrical contacts are important circuit components with diverse industrial applications, and their failure can lead to multiple unwanted effects. Hence, the behavior of electrical contacts is a widely studied topic in the scientific literature based on various approaches, tools, and techniques. The present study proposes a new approach to numerical modeling and simulation based on the Holm contact theory, aiming to study the dependence between the electric potential and the temperature within an electrical contact. Structured in five sections, the research was conducted using COMSOL Multiphysics software (version 5.3) and its solid-state mechanics, electric current, and heat transfer modules in order to highlight contact behavior from mechanical, electrical and thermal points of view: the von Mises stress, contact force, electric field amplitude, variation of the electrical potential along the current path, temperature gradient, and dependence of temperature along the contact elements edges were obtained by simulation, and are graphically represented. The results show that the temperature increase follows a parabolic curve, and that for values higher than 4 mV of voltage drop, the temperature of the contact increases to 79.25 degrees (and up to 123.81 degrees for 5 mV) over the ambient temperature, thus the integrity of insulation can be compromised. These values are close (10–12%) to the analytically calculated ones, and also in line with research assessed in the literature review.

The Thomson influence on semiconductors can be studied by investigating the connection between the presence of thermoelectric and magnetic fields and porosity and the photothermal transport mechanism. Elastic waves, voids, magnetic fields, and thermoelectric effects in plasma are investigated. The governing equations were analyzed for a uniformly distributed and isotropic medium under two-dimensional [electronic and elastic (plasmaelastic)] deformations. The charge density is considered solely dependent on the induced electric current over time. The Laplace-Fourier transforms method in two dimensions is employed to obtain solutions for the primary variables. The recombination process results in the application of electro-mechanical loads and thermal effects on the free surface of a porous medium. The Laplace-Fourier transformations inversion operations help obtain comprehensive solutions in this study. The effects of porosity parameters and silicon (Si) on a semiconductor porous material are considered, and the resulting physical field distributions are analyzed and represented graphically.

• Solar cooling system consisting of a DSSC and a ATEC is established. • The hybrid system is analyzed in terms of energy and exergy. • The hybrid system performance with and without Thomson effect is compared. • The effects of key parameters on the hybrid system performance are revealed. For round shaped cooling space, a dye-sensitized solar cell (DSSC) is used to drive annular thermoelectric cooler (ATEC) to solve the performance deterioration caused by geometric mismatch, in which ATEC considers Seebeck effect, Peltier effect and Thomson effect. Considering all kinds of irreversible losses between DSSC and ATEC, the mathematical formula of performance parameters of hybrid system is derived. The effects of Schottky barrier height, thickness of TiO 2 film, thickness of ATEC, number of thermoelectric elements and annular parameter of the ATEC on the cooling capacity and coefficient of performance (COP) of the coupling system are analyzed theoretically. The theoretical calculation results show that the maximum cooling capacity and COP of the hybrid system are 68.75 W/m2 and 0.071, respectively. In addition, it can be found that the positive Thomson effect had a positive influence on the thermoelectric cooling system. The findings of this work have the potential to provide fresh light of solar-driven annular thermoelectric cooler matching with actual round shaped cooled spaces. [ABSTRACT FROM AUTHOR]

This research deals with the study of Thomson effect in homogeneous photo-magneto-electro- thermoelastic rotating medium, influenced by linearly distributed load and as a result of modified couple stress theory (MCST). The charge density of inertia particles is taken as a function of the time of the induced electric current. The improved Green Nagdhi (GN)-III theory of heat conduction equation and with hyperbolic two-temperature (H2T) is used to formulate the model of the problem. This mathematical model is solved using Laplace's and Fourier's transforms. The complete solutions for various physical fields such as components of displacement, thermodynamic temperature, conductive temperature, carrier density and axial stress as well as couple stress are obtained in the transformed domain. To get the solution in physical domain, numerical inversion techniques have been employed. The Thomson effect with GN -III theory and MCST with hyperbolic two temperature as well as classical two temperature is shown graphically on the physical quantities. [ABSTRACT FROM AUTHOR]

In this paper, the plane wave propagation, in a homogeneous, isotropic thermoelastic solid in the presence of Thomson effect is studied. The problem is solved in the context of the dual-phase-lag model and Lord and Shulman theory. The heat conduction equation is influenced by the Thomson coefficient. The analytical solution of the problem is acquired by using the normal mode method to obtain the stress components, the temperature and the displacement components. The variations of the field quantities have been depicted graphically in the dual-phase-lag model and Lord and Shulman theory for an insulated boundary. From numerical calculations, the effect of Thomson parameter on a homogeneous, isotropic, electro-magneto-thermoelastic material is revealed and discussed. [ABSTRACT FROM AUTHOR]

To harvest the waste heat from exothermic reaction processes, a novel hybrid system model mainly incorporating a high-temperature proton exchange membrane fuel cell (HT-PEMFC) and a duplex thermoelectric cooler is conceptualized to theoretically predict the potential performance limit. The duplex thermoelectric cooler is composed of a thermoelectric generator (TEG) and a thermoelectric cooler (TEC), where the TEG harvests the waste heat to generate electricity and the TEC utilizes the generated electricity for cooling production. A mathematical model is established to estimate the proposed system performance from both exergetic and energetic perspectives considering various irreversible effects, from which effectiveness and practicality of the proposed system can be examined. The hybrid system maximal output power density allows 14.1% greater than that of the basic HT-PEMFC, whereas the according destruction rate density of exergy is decreased by 7.7%. The feasibility and effectiveness of the proposed system configuration are verified. Moreover, substantial parametric analyses indicate that the proposed system performance can be improved by elevating the HT-PEMFC operating temperature, inlet relative humidity and doping level while worsened by enhancing the leak current density, electrolyte thickness and Thomson coefficient. The results acquired may be helpful in designing and optimizing such an actual hybrid system. • An HT-PEMFC/duplex thermoelectric cooler hybrid system is put forward. • Models of both HT-PEMFC and duplex thermoelectric cooler are well described. • Key performance indicators for evaluating the hybrid system are formulated. • Performance features and effectiveness of this kind of hybrid system are revealed. • Effects of decisive variables on the hybrid system performance are discussed. [ABSTRACT FROM AUTHOR]

The effect of Thomson heating on semiconductor medium is studied. Analytical discussions in the presence of thermoelectricity and magnetic field, in the context of photothermal transport process, are made. The interactions between plasma, thermoelectric, magnetic and elastic waves are taken into consideration. The governing equations are investigated in two-dimensional deformations of a homogenous, isotropic medium. The density of charge is taken only as a function of time of the induced electric current. The normal mode technique is used to obtain the physical quantities field under investigation. Some electro-mechanical loads and thermal effect through recombination process are applied at the free surface of semiconductor elastic medium. The distributions of physical fields in this phenomenon are discussed and represented graphically. The results have been discussed under the effects of thermoelectric parameter and Thomson parameter. [ABSTRACT FROM AUTHOR]

• A broad-spectrum photovoltaic system is achieved. • An integrated system is proposed for power and cooling purposes. • The output power density and efficiency of the hybrid system are improved. • The effect of some parameters on the whole system performance is analyzed. For ample utilization of the inlet sunlight, a novel coupled system composed of a photovoltaic module (PVM), a thermoelectric generator (TEG), and a thermoelectric cooler (TEC) is proposed. Short-wave sunlight is sent to PVM to generate electricity, while long-wave sunlight is converted by SSA into heat for TEG-TEC to provide additional cooling. Considering diverse irreversible losses of the cogeneration system, the current relationship between the PVM and the TEG-TEC is analyzed. Besides, the expressions for the performance indexes of the coupled system are deduced under distinct operating conditions. Numerical calculation results illustrate that the power output density and efficiency of the cogeneration system are 3.98% and 3.97% greater than those of a single PVM system in the working current range of TEG-TEC, respectively. Furthermore, the power output density and efficiency of the coupled system with the Thomson effect are, respectively, reduced by 2.47% and 2.46% compared with the proposed system without the Thomson effect. Finally, the impacts of solar irradiance, PVM operating temperature, thermoelectric elements number, environment temperature, and diode ideality factor on the overall module performance are explored. This study results may supply some new ideas for enhancing PVM performance. [ABSTRACT FROM AUTHOR]

In this paper, a one-dimensional thermodynamic model was developed to evaluate the device-level performance of thermoelectric cooler (TEC) with the Thomson effect, contact resistance, gap heat leakage, heat sink, and heat load taken into account. The model was generalized and simplified by introducing dimensionless parameters. Experimental measurements showed good agreement with analytical results. The parametric analysis indicated that the influence of the Thomson effect on cooling capacity continued to expand with increasing current, while the effect on COP hardly changed with current. Low thermal contact resistance was beneficial to obtain lower hot-junction temperature, which can even reduce 2 K compared with the electrical contact resistance in the case study. The gap heat leakage was a negative factor affecting the cooling performance. When the thermal resistance of the heat sink was small, the negative effect of heat leakage on performance would be further enlarged. The enhancement of heat load temperature would increase the cooling power of the TEC. For example, an increase of 5 K in heat load can increase the cooling capacity by about 4%. However, once the current exceeded the optimum value, the raising effect on the cooling power would be weakened. The research can provide an analytical approach for the designer to perform trade studies to optimize the TEC system. [ABSTRACT FROM AUTHOR]

The maximum conversion efficiency of a thermoelectric module composed of p- and n-type materials has been widely calculated using a constant property model since the 1950s, but this conventional model is only valid in limited conditions and no Thomson heat is accounted for. Since Thomson heat causes the efficiency under- or over-rated depending on the temperature dependence of Seebeck coefficient, it cannot be ignored especially in large temperature difference between the hot and cold sides. In addition, incorrect Joule heat is taken into consideration for heat flux evaluation of a thermoelectric module at thermal boundaries due to the assumption of constant properties in the conventional model. For this reason, more practical predictions for efficiency and output power and its corresponding optimum conditions of p- and n-type materials need to be revisited. In this study, generic formulae are derived based on a cumulative temperature dependence model including Thomson effect. The formulae reliably predict the maximum efficiency and output power of a thermoelectric module at a large temperature. [ABSTRACT FROM AUTHOR]

The problem considered is that of an isotropic, micropolar thermoelastic medium with voids subjected to the Thomson effect. The solution to the problem is presented in the context of the refined multiphase-lags theory of thermoelasticity. The normal mode analysis was used to obtain the analytical expressions of the considered variables. The nondimensional displacement, temperature, microrotation, the change in the volume fraction field and stress of the material are obtained and illustrated graphically. The variations of these quantities have been depicted graphically in the refined-phase-lag theory, Green and Naghdi theory of type II, Lord and Shulman theory and a coupled theory. The effects of the Thomson parameter and phase lag parameters on a homogeneous, isotropic, micropolar thermoelastic material with voids are revealed and discussed. Some particular cases of interest are deduced from the present investigation. [ABSTRACT FROM AUTHOR]

Summary: Contact resistance and Thomson heat are the two major factors in the analysis of thermoelectric modules that are often being ignored. Each of these factors has an adverse effect on the output performance of a thermoelectric module. In this study, expression for maximum power output that includes both the contact resistance and the Thomson effect has been optimized using genetic algorithm to obtain the optimum geometric parameters of a thermoelectric generator. Each leg has electrical and thermal contact resistances of 2 × 10−9 Ω m2 and 1.8 × 10−4 m2 K/W, respectively. The results of the optimization for the maximum power output and the energy conversion efficiency for Skutterudites thermoelectric materials operating at a maximum temperature difference of 500 K are 30.1 W and 9.87%, respectively. When only the contact resistances are not included, the results rise by 19.4% for the maximum power output and 11.65% for the energy conversion efficiency. When only the Thomson heat is not included, the result rise by 2.66% for the maximum power output and 5.67% for the energy conversion efficiency. These two factors should always be considered in the analysis of thermoelectric modules, neglecting them can lead to an overestimation of the output performance. [ABSTRACT FROM AUTHOR]

We have observed how thermoelectric effects that result in asymmetric melting of silicon wires are suppressed for increasing electric current density (J). The experimental results are investigated using numerical modeling of the self-heating process, which elucidates the relative contributions of the asymmetric thermoelectric Thomson heat (~J) and symmetric Joule heating (~J2) that lead to symmetric heating for higher current levels. These results are applied in modeling of the self-heating process in phase-change memory devices. While, phase-change memory devices show a clearly preferred operation polarity due to thermoelectric effects, nearly symmetric operation can be achieved with higher amplitude and shorter current pulses, which can lead to design of improved polarity-invariant memory circuitry. [ABSTRACT FROM AUTHOR]

Summary: A hybrid analytical‐computational method is developed to calculate the temperature distribution and electrical performance of thermoelectric generators (TEG). The geometrical complexities of thermo‐elements in real modules are ignored and the TEG is assumed to be made of five distinct layers. The power output is obtained by algebraic expressions and considered as a heat sink expression in the energy equation. The coupling of thermoelectric and energy equations is handled by developing user defined functions (UDF) in the numerical solution procedure. Accordingly, the heat flow is divided into two parts accounting for the thermoelectric phenomena and the Fourier conduction in the thermoelectric layer. The model is validated and the accuracy of the results is examined against two detailed simulations as well as the available experimental data. It is shown that the model is accurate with an average deviation of 8% to 10% compared to the experiments which is only 4% to 5% higher than the detailed rigorous numerical solutions. The influence of Thomson effect is also found to be around 1%. Moreover, the effect of element numbers with a certain amount of material is investigated and it is revealed that the appropriate number of elements depends on the module temperature due to the Thomson effect. [ABSTRACT FROM AUTHOR]

In this article, the novel mathematical model under the effect of Thomson heating of a semi-infinite semiconductor elastic medium is expressed. The thermoelasticity theory is applied in the presence of magnetic field when the medium illuminated by a laser pulse in context of photothermal excitation. The discussions are focused on studying the overlapping between plasma, thermal, electro-magnetic and elastic waves when they propagated in the medium. The two dimensional (2D) deformations is used in the governing equations when the medium is homogenous and isotropic. The charge density of induced electric current is expressed for a time functionally only. The physical fields are obtained when use the normal mode technique with some thermal, mechanical and plasma loads occur at the free surface of elastic semi-infinite semiconductor medium. The numerical calculations of physical field's distributions are discussed and shown graphically under the effect of Thomson parameter.

The effect of rotation and hydrostatic initial stresses during electromagnetic field which is fallen on the outer surface of semiconductor medium is studied. The Thomson influence in context of photo thermal excitation process is investigated. The thermoelectricity theory is applied explain the waves behavior in the elastic semiconductor homogenous, isotropic medium. The governing equations describe the overlapping between plasma, electro-magnetic and elastic waves in two dimensional deformations when the medium is in rotation. The induced electric current is studied only when the charge density is a function of time. The normal mode analysis is a mathematical method which is used to get the physical fields distributions under investigation. The mechanical forces, electromagnetic effects thermal loads and plasma diffusion recombination process are taken at the outer free surface of the medium to obtain the complete solutions. All distributions of waves of physical quantities are represented graphically and discussed under the influence of rotation, initial stresses and Thomson parameter.

The effect of Thomson heating of semiconductor medium is studied. Analytical discussions are made in the presence of thermoelectricity theory and magnetic field in context of Photothermal transport process. The interactions between plasma, thermoelectric, electromagnetic and elastic waves are taken into consideration. The governing equations are investigated in two dimensional deformations of homogenous, isotropic medium. The density of charge is taken as a function of time only of the induced electric current. The normal mode technique is used to obtain the physical quantities field under investigation. Some electro-mechanical loads and thermal effect through recombination process are applied on the free surface of semiconductor elastic medium. The distributions of physical fields in this phenomenon are discussed and represented graphically. The results have been discussed under the effect of thermoelectric parameter and Thomson parameter. [ABSTRACT FROM AUTHOR]

Resistance spot welding (RSW) of aluminum-aluminum (Al-Al) is known to be very challenging, with the asymmetric growth of the weld nugget often observed. In this article, a semicoupled electrical-thermal-mechanical finite element analysis (FEA) procedure was established to simulate the RSW of two layers of AA6022-T4 sheets using a specially designed Multi-Ring Domed (MRD) electrodes. Critical to the modeling procedure was the thermoelectric (including the Peltier, Thomson, and Seebeck effects) analyses to simulate the asymmetric nugget growth in the welding stage. Key input parameters such as the Seebeck coefficients and high-temperature flow stress curves were measured. Simulation results, experimentally validated, indicated that the newly developed procedure could successfully predict the asymmetric weld nugget growth. Simulation results also showed the Seebeck effect in the holding stage. The simulations represent the first quantitative investigation of the impact of the thermoelectric effects on resistance spot welding. [ABSTRACT FROM AUTHOR]

The vapor–liquid–solid (VLS) mechanism is probably the most versatile method to fabricate semiconductor nanowires and several investigations assume a compositionally homogeneous catalyst particle. In this investigation we address the compositional homogeneity of the catalyst particle during growth of nanowires. Using diffusion calculations, we show that the particle is indeed homogeneous during VLS growth, but can have a strong concentration gradient during vapor–solid–solid growth, that is, growth with a solid particle. We also show that the response to a concentration change is extremely fast, meaning that if the concentration at the surface of the particle changes, the entire particle reaches this new concentration effectively instantaneously. [ABSTRACT FROM AUTHOR]

This study investigates a strong magnetic field acting over an elastic rotator semiconductor medium. The Thomson effect due to the magnetic field during the photothermal transport process is studied, and the thermoelectricity theory is used to explain the behavior of waves in the homogenous and isotropic medium under the effect of variable thermal conductivity. The variable thermal conductivity is considered as a linear function of the temperature. The two-dimensional deformation equations are used to describe the overlaps among plasma, electrical, thermal, and magneto-elastic waves. The charge density of inertia-particles is considered as a function of time for studying the induced electric current. The normal mode analysis is used to obtain the exact solutions of the physical field distributions as part of this phenomenon. To obtain the complete solutions of the physical field quantities, the certain mechanical loads, electromagnetic effects, thermal effects, and plasma recombination process are applied herein. The results of the physical distributions are graphically depicted and discussed in consideration of the internal heat source, rotation, and Peltier coefficient. [ABSTRACT FROM AUTHOR]

The electronic scattering rates in metals after ultrashort pulsed laser heating can be drastically different than those predicted from free electron theory. The large electron temperature achieved after ultrashort pulsed absorption and subsequent thermalization can lead to excitation of subconduction band thermal excitations of electron orbitals far below the Fermi energy. In the case of noble metals, which all have a characteristic flat d-band several electron volts well below the Fermi energy, the onset of d-band excitations has been shown to increase electron-phonon scattering rates by an order of magnitude. In this paper, we investigate the effects of these large electronic thermal excitations on the ultrafast thermoelectric transport properties of gold, a characteristic noble metal. Under conditions of strong electron-phonon nonequilibrium (relatively high electron temperatures and relatively low lattice temperatures, Te>TL), we find that the Wiedemann-Franz law breaks down and the Seebeck coefficient is massively enhanced. Although we perform representative calculations for Au, these results are expected to be similar for the other noble metals (Ag and Cu) due to the characteristic large d-band separation from the Fermi energy. [ABSTRACT FROM AUTHOR]

Consider the growth of a nanowire by a step-flow mechanism in the course of vapor-liquid-solid and vapor-solid-solid processes. The growth is initiated by the nucleation of a circular step at the nanowire-catalyst interface near the edge of the nanowire (the triple junction) and proceeds by the propagation toward the center by the Burton–Cabrera–Frank mechanism. Two cases are considered: (i) bulk transport, where the interfacial diffusion of adatoms and the step motion are coupled to the diffusion flux of atoms from the bulk of the catalyst particle, and (ii) surface transport, where atoms from the vapor phase are adsorbed at the surface of the catalyst particle and diffuse along the surface toward the triple line, whence they diffuse to the nanowire-catalyst interface. The attachment kinetics of adatoms at the step, the adsorption kinetics of atoms from the bulk phase, the exchange kinetics at the triple contact line, and the capillarity of the step are taken into account. In case (i) the problem is reduced to an integral equation for the diffusion flux of atoms from the bulk phase to the nanowire-catalyst interface. This equation is solved numerically, and the flux, interfacial concentration of adatoms, and the bulk concentration near the interface are determined. The step velocity is calculated as a function of the step radius and the kinetic parameters. As a result, the growth rate of a nanowire is computed as a function of its radius. In case (ii) analytical solutions for the surface and interfacial concentrations are obtained. In the absence of step capillarity, an analytical formula for the dependence of the nanowire growth rate on the nanowire radius is derived. It is shown in both cases (i) and (ii) that the nanowire growth rate decreases with increasing nanowire radius due to the decrease in the magnitude of the concentration gradients. However, in case (ii), in the limit of negligible desorption of adatoms into the gas phase, the nanowire growth rate is independent of the radius. It is also shown that in the presence of step capillarity (the Gibbs–Thomson effect) increases the nanowire growth rate. [ABSTRACT FROM AUTHOR]

Despite significant attention paid to thermoelectric generators in the energy conversion field, their limited output performance has restricted their large-scale applications. Therefore, there is a pressing need to conceive a novel thermoelectric device concept that can strengthen their competitiveness. In this context, the concept and principle of thermoelectric (TE) transistor with ultrahigh performance is a demand-driven innovation. Built on the foundation of a PNP structure, TE transistor only relies on the Seebeck voltage to operate normally. This work employs P-type Bi 0.5 Sb 1.5 Te 3 and N-type Bi 2 Te 2.97 Se 0.03 as the component materials. By considering the conduction heat, Joule heat, Thomson heat, and temperature-dependent material properties, a one-dimensional heat transfer model was used to obtain the nonlinear temperature profile inside TE transistor. Further, the structure and operation conditions of TE transistor with varying geometric dimensions were determined based on the hole concentration distribution and build-in voltage variation. Finally, the optimal concentrations and geometric dimensions of TE transistor were obtained using a compromise method. The calculation results reveal that TE transistor can achieve an optimal output power of 133.7 mW under a temperature difference of 50 K (T h = 353 K, T c = 303 K) with the corresponding conversion efficiency of 7.73%. This work provides theoretical guidance for future experimental validation of TE transistor. • A feasible and comprehensive theoretical design for thermoelectric (TE) transistor is developed. • The non-linear temperature profile inside TE transistor is determined based on the heat conduction analysis. • Influence of the Thomson effect on TE transistor output performance is analyzed. • Output power of TE transistor is improved greatly by the geometry optimization. [ABSTRACT FROM AUTHOR]

Measurements of Thomson (later Lord Kelvin) coefficients are made in an evacuated region on a silver sample with a novel transducer in temperature intervals T A ± 20 K {T_{A}}\pm 20\hspace{0.1667em}\text{K} , where the T A {T_{A}} are very carefully controlled ambient temperatures. This is the first systematic examination of Thomson coefficients in these temperature intervals. The Thomson coefficients when plotted against T, the temperature of measurement, are found to be discontinuous precisely at T A {T_{A}}. When the Thomson coefficients are multiplied by a transformation involving T and T A {T_{A}} , a linear curve in T results. Examinations here of measurements of Thomson coefficients produced by others show multiple values at T in some cases and odd behavior in other cases. Multiplying the results of others by the transformation discovered here almost always produces linear curves. The conclusions are the following. (1) Thomson's explicit assumption that the Thomson effect involves no energy exchange with surroundings was wrong. (2) Any non-equilibrium thermodynamic approach to deriving the Thomson effect must take into account the energy exchange with the surroundings and consequently must be made in three dimensions. (3) From the work here and that of others, the energy exchange with the environment is probably mostly thermal radiation. [ABSTRACT FROM AUTHOR]

Since thermoelectric technology is a clean method to produce electrical energy, many researchers have been attracted to this field, recently. Different modelling and simplifying studies have been done to gain the best performance and optimum geometry of thermoelectric devices, but Thomson heat has not been considered, seriously. In this paper, using an analytical model, the effect of Thomson heat on the power and efficiency of a thermoelectric generator is investigated and amount of its influence in different conditions is explained. To compare different materials with the aspect of the rate of Thomson heat influence, Bi-Te and Pb-Te alloys are considered. It is seen that in different conditions, Thomson heat has different effects on the system efficiency. In low temperature ranges (lower than 650 K), although it has negative influence on the power and efficiency for both materials, Bi-Te has better performance than the other one. For the temperature ranges higher than 650 K, Pb-Te can be appropriate material since Thomson heat has positive effect on the power and efficiency for it. [ABSTRACT FROM AUTHOR]

The analytical expressions derived using simple models provide clear insights on the processes in thermoelectric coolers. The model of constant transport coefficients (CTC) considers that the thermal conductivity, the electrical resistivity and the Thomson coefficient are constants. The version of the CTC model that has become standard in the description of the global energy balance may yield grossly inaccurate predictions for thermoelectric cooling applications. We show that these failures can be avoided by accurately describing the Thomson effect in the energy balance. Calculations for bismuth telluride semiconductors show that deviations as large as a factor of three in the Thomson power contribution to the global balance may be found under conditions of practical interest. Compared to the standard version (valid only for moderate temperature gradients), the improved version (valid for highly nonlinear temperature distributions) of the CTC model predicts that a larger fraction of the power released by the electric current leaves the thermoelectric element through the hot boundary. Significant differences in the estimations of the cooling capacity and the coefficient of performance of the thermoelectric cooler are also observed. [ABSTRACT FROM AUTHOR]

Described herein is a detailed and comprehensive multiphysics model of a thermoelectric generator (TEG). The one-dimensional model uses electrical–thermal analogies solved for transient response using SPICE. There are many advantages and applications of thermoelectric generators. Wider use and application advancements are generally limited by the tools available for engineering and scientific studies. Currently, available modeling tools are limited by some combination of speed, platform capabilities, or missing physics that are not used or assumed to be negligible. The TEG module model herein is made up of two sub-models, the thermoelement model and the non-thermoelement model. Rather than a lumped thermoelement model, the model herein makes use of distributed physics that include the following: Thomson effect, temperature dependence, mass, Joule heat, thermal resistance, Seebeck effect, and electrical resistance. The non-thermoelement model takes into account temperature dependence and simulates Joule heat generation, thermal resistances, thermal and electrical interface resistances, and mass for and between the ceramic, copper, and solder. The comprehensive model herein was correlated to experimental data that simultaneously varied electrical current and hot and cold side temperatures with time. Very minimal adjustments to reported thermoelectric properties were required to almost perfectly match the experimental transient power output. The effects of the non-thermoelement model, distributed Thomson effect model and distributed temperature dependent property model were quantified. The model ran very quickly, taking 2.5 real-time seconds to run a 4000 s transient simulation. [ABSTRACT FROM AUTHOR]

• We studied the influence of Thomson effect on the performance of the Thermoelectric generators (TEGs) with temperature-dependent Seebeck coefficient. • The performance of the TEGs can either be depressed or promoted by the Thomson effect, depending on the temperature difference between the cold- and hot-ends and the Seebeck coefficient of the legs. • The Thomson effect always weakens the improvement of TEG performance induced by increasing the figure of merit (ZT) of the thermoelectric materials. Heat can be converted to electricity by thermoelectric generators (TEGs) directly. In consideration that the thermoelectric properties of the legs depend on the temperature strongly, the Thomson effect affects heat production, heat transfer, and energy conversion. Consequently, the Thomson effect cannot be neglected during evaluating the performance of the TEGs. In this work, we studied the influence of Thomson effect on the performance of the TEGs. Linear and polynomial fitting Seebeck coefficients of the thermoelectric materials are adopted and the three-dimensional thermo-electric coupled equations are solved by the finite-element method to obtain the output power and the conversion efficiency. Our results showed that the performance of the TEGs can either be depressed or promoted by the Thomson effect, depending on the temperature difference between the cold- and hot-ends and the Seebeck coefficient of the legs. Moreover, the Thomson effect always weaken the improvement of TEG performance by the means of increasing the figure of merit (ZT) of the thermoelectric materials. We then applied our model to study the performance of TEGs with Bi 2 Te 3 as the legs and found the difference between the conversion efficiencies with Thomson effect and without Thomson effect increases fast with the temperature difference between the hot- and cold-ends. This study could be useful for guiding the searching for TEG system that are potentially high performance and compatible with environmental-friendly application. [ABSTRACT FROM AUTHOR]

A combined system model consisting of a high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC), a regenerator and a thermoelectric generator (TEG) is proposed, where the TEG is applied to harness the generated waste heat in the HT-PEMFC for extra electricity production. The TEG considers not only the Seebeck effect and Peltier effect but also the Thomson effect. The mathematical expressions of power output, energy efficiency, exergy destruction rate and exergy efficiency for the proposed system are derived. The energetic and exergetic performance characteristics for the whole system are revealed. The optimum operating ranges for some key performance parameters of the combined system are determined using the maximum power density as the objective function. The combined system maximum power density and its corresponding energy efficiency and exergy efficiency allow 19.1%, 12.4% and 12.6% higher than that of a stand-alone HT-PEMFC, while the exergy destruction rate density is only increased by 8.6%. The system performances are compared between the TEG with and without the Thomson effect. Moreover, the impacts of comprehensive parameters on the system performance characteristics are discussed. The obtained results are helpful in developing and designing such an actual combined system for efficient and clean power production. • TEGs are proposed as a waste heat recovery technology for HT-PEMFCs. • Thermal-electrochemical losses within the proposed system are described. • Performance parameters evaluating the proposed system are obtained. • The proposed system is effective for waste heat recovery. • Effects of some design parameter and operating conditions are revealed. [ABSTRACT FROM AUTHOR]

We present a simplified, rapid, and accurate method for the measurement of the thermoelectric Thomson coefficient by the dynamical heating of a suspended wire by an alternating current. By applying a temperature gradient across the wire, we find that the response at the second harmonic of the excitation frequency is directly proportional to the Thomson coefficient. The absolute thermoelectric coefficient of a single material can therefore be extracted with high precision by using a phase sensitive detector. We test our method on platinum and nickel wires and develop both analytical and numerical models to determine the leading sources of error. [ABSTRACT FROM AUTHOR]

Presents the experimental study of the ion emission from a 0.53-μm laser-produced plasma. Detection efficiency for ion velocities; Thomson parabola traces of the emitted ions; Ion velocity distribution obtained by superposition of several shots on the film.

To evaluate the Thomson effect on the temperature increase in Ge _2 Sb _2 Te _5 (GST)-based phase-change random access memory (PCRAM), we created new dimensionless numbers based on Buckingham’s П theorem. The influence of the Thomson effect on the temperature increase depends on the dominant factor of electrical resistance in a PCRAM cell. When the effect is dominated by the volumetric resistance of the phase-change material $\left(C=\tfrac{{\rho }_{c}}{{\rm{\Delta }}x/\sigma }\ll O(1)\right),$ the dimensionless evaluation number is $B=\tfrac{{\mu }_{T}\sigma {\rm{\Delta }}\phi }{k},$ where ρ _c is the contact resistance, Δ x is the thickness of PCM, σ and k are the electrical and thermal conductivities, μ _T is the Thomson coefficient, and Δ ϕ is the voltage. When the contact resistance cannot be ignored, the evaluation number is B /(1 + C ). The characteristics of hexagonal-type crystalline GST in a PCRAM cell were numerically investigated using the defined dimensionless parameters. Although the contact resistance of GST exceeded the volumetric resistance across the temperature range, the ratio of contact resistance to the whole resistance reduced with increasing temperature. Moreover, increasing the temperature of GST enhanced the influence of the Thomson effect on the temperature distribution. At high temperatures, the Thomson effect suppressed the temperature increase by approximately 10%–20%.

The essential target of the tumor’s treatment is how to destroy its tissues. This work is dealing with the thermal damage of the tumor tissue due to the thermoelectrical effect based on the Thomson effect. The governing equation of tumor tissue in concentric spherical space based on the thermal lagging effect is constructed and solved when the surface of the tumor tissue is subjected to a specific electric voltage. Different voltage and resistance effects have been studied and discussed for three different types of tumor tissues. The thermal damage quantity has been calculated with varying values of voltages and times. The voltage has significant effects on the temperature and the amount of the irreversible thermal damage of the tumor. Electrotherapy is a successful treatment. This work introduces a different model to doctors who work in clinical cancer to do experiments using electricity to damage the cancer cells.

Abstract An original model of directional eutectic growth for lamellar eutectics is presented. This model is based on the analysis of thermodynamic equilibrium at the solidification front. Contrary to previous ones, this model does not use linearization hypothesis on the alloy phase diagram and takes into account variations of densities between phases. Moreover, curvature effects are considered on thermodynamic equilibrium at the solidification front. Its numerical implementation is made possible through a coupling with thermodynamic software based on the CALPHAD approach. This new numerical model is applied to the Al-Al 2 Cu eutectic structure and compared to the Jackson-Hunt theory. Large differences between results of the present model and this theory are observed at high growth rate. In particular, curvature effects on phases concentrations can no more be modeled using a linear approximation, as in the Gibbs-Thomson relation. A good agreement of the numerical model with reported experimental studies is observed for a large range of growth velocities. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Multi-scale, multi-method integration of geological constraints, with new interpretations of potential field data and seismic reflection data, has resulted in a comprehensive structural interpretation of the southern Thomson Orogen, eastern Australia. The interpretation reveals ∼50 major faults and shear zones, many of which can be traced for several hundred kilometres. The interpretation suggests that the southern Thomson Orogen can be subdivided into several structural domains that can be distinguished by differences in: (i) spatial orientation, (ii) geographic distribution, and (iii) partly the timing of major faults, but also to varying degrees by (iv) the evolution and spatial orientation of other structural elements, such as folds, minor faults and fractures, (v) broader lithological trends, (vi) stratigraphy, and (vii) structural style. The two largest domains are the Western Structural Domain that contains numerous faults and shear zones, and the fold-dominated Eastern Structural Domain, which is more strongly affected by late- to post-Devonian thrusting than the Western Structural Domain. Notwithstanding their differences, the domains can be integrated into a coherent structural model for the southern Thomson Orogen, which suggests that the area represents a set of megafolds or oroclines, which may have formed during the Bindian Orogeny. [ABSTRACT FROM AUTHOR]

A thermodynamic model for a concentrating solar thermoelectric generator considering the Thomson effect combined with Fourier heat conduction, Peltier, and Joule heating has been developed and optimized in MATLAB environment. The temperatures at the hot and cold junctions of the thermoelectric generator were evaluated by solving the energy balance equations at both junctions. The effects of the solar concentration ratio, input electrical current, number of thermocouples, and electrical load resistance ratio on the power output and energy and exergy efficiencies of the system were studied. Optimization studies were carried out for the STEG system, and the optimum number of thermocouples, concentration ratio, and resistance ratio determined. The results showed that the optimum values of these parameters are different for conditions of maximum power output and maximum energy and exergy efficiency. The optimum values of the concentration ratio and load resistance ratio for maximum energy efficiency of 5.85% and maximum exergy efficiency of 6.29% were found to be 180 and 1.3, respectively, with corresponding power output of 4.213 W. Furthermore, at higher concentration ratio (C = 600), the optimum number of thermocouples was found to be 101 for maximum power output of 13.75 W, maximum energy efficiency of 5.73%, and maximum exergy efficiency of 6.16%. Moreover, the optimum number of thermocouple was the same for conditions of maximum power output and energy and exergy efficiency. The results of this study may provide insight for design of actual concentrated solar thermoelectric generator systems. [ABSTRACT FROM AUTHOR]

To utilize heat from round shaped heat sources or heat sinks effectively, a segmented annular thermoelectric generator was proposed. Each leg is composed of two materials with different optimum operating temperatures jointed in series. Based upon a developed theoretical model, the influences of annular shape parameter, height ratios of high temperature segment to leg in p- and n-type legs, temperature ratio and load ratio on the performance of segmented annular thermoelectric generator were studied. A finite element method was adopted to consider the Thomson effect and temperature-dependence of materials. Performance comparisons with simply non-segmented annular thermoelectric generators were conducted. For application security, the interface temperatures were analyzed. Results show that compared to a simply non-segmented annular thermoelectric generator, the superiority of segmented annular thermoelectric generator becomes visible with rising temperature ratio. As the annular shape parameter increases, the power rises firstly and then declines, and the optimal annular shape parameter is around 1.0, but not strictly equal to 1.0. Besides, the optimal ranges of height ratios in p- and n-type legs for higher performance are identified. The current study demonstrates the potential of segmented annular thermoelectric generator from the perspectives of performance and practicability. [ABSTRACT FROM AUTHOR]

In this paper, the thermodynamics evaluation of an irreversible CPV-TEG cogenerating system, having Siemens SP75 PV module and commercially available Bi 2 Te 3 TE module, has been investigated for wide solar spectrum to encompass the winter and summer solar radiation. Modeling and simulation of the hybrid system has been carried out to understand the feasibility of the system and to determine the irreversibilities present in the hybrid system. The irreversibilities or exergy destruction caused by the irreversible conversion process of solar energy into electricity are calculated using exergy analysis based on second law of thermodynamics. The various exergy losses occurring in the hybrid system have been calculated using exergy analysis. The effects of the incident solar irradiance varying in a wide range from 100 W/m 2 to 1000 W/m 2 , TEG junction temperature ratio, concentration ratio, TEG current, Thomson coefficient, irreversibilities or exergy destruction and the incoming solar radiation exergy have been studied. The results showed that the Thomson effect has adverse effect on the performance of the hybrid system and the irreversibilities increase with increase in concentration ratio, C . Further, the power output of hybrid system increases by 86% as C increases from 1 to optimum value of 3 and the exergy efficiency is higher than the energy efficiency by 8%. The higher values of the irreversibilities make the system less inefficient and therefore, significant improvements are required because the elevated temperature could result in hot spots formation. The results of this analysis may be helpful in designing of practical CPV-TEG hybrid system. [ABSTRACT FROM AUTHOR]

Analytical solutions of transient temperature distributions within semiconductor elements are presented in this study. The performance of a thermoelectric cooler (TEC) under the influences of the Thomson effect, Joule heating, and combined radiation and convection cooling is investigated. The solution of the temperature distributions is obtained by solving the governing heat conduction equation using the superposition technique with the aid of a special transformation function. The closed-form transient temperature profiles for the semiconductor element sizes, applied current, cooling load, heating power, power consumption, and the system coefficient of performance (COP) of a TEC are presented. The interrelationships between the aforementioned effects are examined in detail. The analytical temperature solution presented in this study can be utilized by design engineers in the thermoelectrics industry as a convenient means to demonstrate compliance of the device heating or cooling design specification requirements. [ABSTRACT FROM AUTHOR]

The study of annular thermoelectric generators (ATEG) has attracted more attention in recent years due to their ability to cover round shaped surfaces. Moreover, transient and pulsed inputs have been introduced as some of the effective methods to enhance the performance of thermoelectric devices. Hence, in the present study, a three-dimensional transient simulation of ATEG including the influence of Thomson effect is carried out based on finite element method. The effect of pulsed heat inputs on the performance of ATEG is studied considering rectangular, triangular, sinusoidal and two types of the sawtooth input functions for modeling the transient heat load. Electric current, voltage, output power and conversion efficiency of ATEG under pulsed and steady-state heating are compared. The effects of two critical parameters, the ratio of maximum heat flux to minimum heat flux ( b / a ) and duty cycle ( t 0 / τ ) values on the performance of ATEG are studied. Results indicate that transient pulsed heating enhances the efficiency of ATEG for all types of heat input functions. In addition, it is found that rectangular input function leads to better results compared to other functions. Also, it is shown that for a constant amount of duty cycle, the increment of ( b / a ) increases the performance of ATEG unit. For duty cycle value of 0.1 and ( b / a = 48 ) a maximum efficiency enhancement of 249.36% is achieved when the rectangular input function is employed. It is found that in the range of the studied values of ( b / a ) , the duty cycle of 0.4 leads to better results. A comparison of results with and without Thomson effect proves that the Thomson effect decreases the performance of ATEG. Additionally, it is observed that for sawtooth input functions, the implementation of heat load gradient plays an important role determining the performance. [ABSTRACT FROM AUTHOR]

The thermodynamic investigations on the thermoelectric devices (TEs) discard the influence produced by the non-linear Thomson effect. It could direct the incomplete/partial modelling solutions laterally through some critical gaps in the performance evaluation of these devices. On the contrary, a suitable arrangement of several designing constraints for TEs is essential to improve their operating characteristics. In this context, the modeling of multi-element single- and two-stage thermoelectric generators based on the thermodynamic principles is done in MATLAB 9.2. The irreversibility due to Thomson influence along with Joule/Fourier effects are undertaken for the system modelling. The optimization of the generators is done in pursuance of obtaining the optimal values of four input parameters using two different evolutionary algorithms, viz., NSGA-II and MOEA/D. The optimum solutions from the Pareto front of two-/three- objective are found using different decision-making methods, viz., TOPSIS, Fuzzy, and LINMAP. It is observed that the proposed optimization yields trivial variances amongst ideal/obtained solutions, named as the deviation index, in comparison with the single/dual ones. In addition to this, sensitivity analysis is done to examine the impact of Thomson effect on the output power/thermal efficiency of the generators. The test results obtained through NSGA-II are in coherence with those of the data and figures reported in the available literature. [ABSTRACT FROM AUTHOR]