In-plane Temperature Research Articles

Mesh-free thermal buckling analysis of multilayered composite plates based on an nth-order shear deformation theory

This study aims at exploring buckling behavior of multilayered composite plates including functionally graded material (FGM) layer in thermal environments by using a mesh-free method. The thermal buckling of the composite plate laminated with FGM layer is formulated by an improved Moving Kriging (MK) meshless method based on an nth-order shear deformation theory which enables the optimal order number to provide the best prediction to be chosen. In the improved MK mesh-free method, the covariance basis function is presented in a compactly supported form to build the shape functions with no fitting parameters. Four types of multilayered composite plates with FGM layer subjected to in-plane and through-thickness temperature changes are considered, and the material properties are both position and temperature dependent. Performance accuracy of the proposed mesh-free method is first confirmed by comparing the computed results with the reference solutions available in the literature, followed by the detailed parametric studies in which the effects of the ingredient fraction, FGM constituents, composition scheme, plate geometric parameter and boundary condition are scrutinized focusing on temperature dependency of the material properties.

Thermal postbuckling behavior of CNT-reinforced composite sandwich plate models resting on elastic foundations with tangentially restrained edges and temperature-dependent properties

Buckling and postbuckling behaviors of sandwich plates reinforced by single-walled carbon nanotube (CNT), rested on elastic foundations and subjected to uniform temperature rise, are investigated in this article. CNT is embedded into matrix phase through uniform or functionally graded distributions. The properties of constituent materials are assumed to be temperature-dependent, and effective properties of nanocomposite are determined by extended rule of mixture. Two models of sandwich plates with face sheets and core layer reinforced by CNTs are presented. Formulations are based on the first-order shear deformation theory taking geometrical nonlinearity, initial geometrical imperfection, plate-foundation interaction, and elasticity of tangential edge constraints into consideration. Analytical solutions of deflection and stress function are assumed, and Galerkin method is applied to derive nonlinear temperature–deflection relation from which buckling temperatures and thermal postbuckling paths are obtained through an iteration algorithm. Numerical examples show the effects of CNT volume fraction, distribution patterns, in-plane edge constraint, elastic foundations, geometrical ratios, initial imperfection, and temperature dependence of properties on thermal postbuckling behavior of nanocomposite sandwich plates. The most important finding is that sandwich plate constructed from CNT-poor nanocomposite core layer and thin homogeneous face sheets with partially movable edges bring the best capacities of thermal buckling resistance and postbuckling load carrying.

Field Analysis of three different Silicon-based Technologies in Composite Climatic Condition

This paper investigates the performance of the photovoltaics based on the filtering techniques, performance monitoring metrics, and numerical methodologies at real outdoor conditions. The experimental study is carried out on a set of nine photovoltaics modules consisting three modules of each technology i.e. Multi-crystalline (mc-si), Heterojunction with Intrinsic Thin layer (HIT) and Amorphous Silicon (a-si). Various electrical performance data has been collected and characterized for a period of three years in the composite climate of India. The research methodology includes mapping of series resistance, estimation of monthly average effective peak Power (Peff), Performance Ratio (PR) and temperature corrected Performance Ratio (PRT_CORR) has been carried out. The average percentage reduction in the effective peak power (ΔPeff) for the mc-si, a-si and HIT modules were 15.8%, 17.2%, and 7.1% respectively over a period of three years. The monthly average PR for mc-si, a-si and HIT modules were 0.70, 0.82 and 0.83 respectively for the same period. The PR T_CORR over three-year duration for mc-si is 0.77, for a-si is 0.89, and 0.90 for a HIT modules respectively. The annual degradation is 1.5%, 1.6% and 0.39% for mc-si, a-si and HIT modules respectively. The increment in the series resistance has been calculated estimated using the procedure I of the IEC 60,891 Edi 2.0 and the mapping of the series resistance has been done with the matrix of in-plane irradiance and module temperature. Further, the uncertainty calculations of series resistance have been estimated for three different irradiation ranges i.e. 1000 W/m2, 900 W/m2 and 800 W/m2 which is around 4% to ensure the sanctity of measurements and calculations. It has been observed that module degrades faster in hot climatic zones. The interpretation of measured and calculated results, correlation of bus-bar corrosion, and module degradation have been delineated for the composite climate. Finally, it also discusses the usage of the above-proposed methods/tools for optimization of solar cell design parameters at different climatic conditions.

Electrical and Thermal Transport Properties of Layered Superconducting Ca10(Pt₄As8)((Fe0.86Pt0.14)2As₂)₅ Single Crystal.

We have synthesized single crystals of iron-based superconducting Ca10(Pt4As8)((Fe0.86Pt0.14)2As2)5 and performed extensive measurements on their transport properties. A remarkable difference in the behavior and a large anisotropy between in-plane and out-of-plane resistivity was observed. Disorder could explain the in-plane square-root temperature dependence resistivity, and interlayer incoherent scattering may contribute to the out-of-plane transport property. Along the ab plane, the estimated value of the coherence length is 15.5 Å. From measurements of the upper critical magnetic field Hc2 (T ≥ 20 K), we estimate Hc2(0) = 313 T. Thermal conductivity for Ca10(Pt4As8)((Fe0.86Pt0.14)2As2)5 is relatively small, which can be accounted for by the disorder in the crystal and the low-charge carrier density as verified by the Hall effect.

A general comparison the surface layer degree on the out-of-phase and in-phase vibration behavior of a skew double-layer magneto–electro–thermo-elastic nanoplate

The present study investigates and compares the value of the surface layers on the out-of-phase and in-phase vibration behavior of skew double-layer magneto–electro–thermo-elastic (DLMETE) nanoplates. These two nanoplates are coupled by an elastic medium named van der Waals forces; furthermore, the DLMETE nanoplates are surrounded by Winkler and the shear moduli of elastic foundations. The two nanoplates are moving in the same direction in the out-of-phase case; in contrast, in the in-phase mode, those two nanoplates are moving in the opposite direction. Manipulation of the refined plate, surface energy, and nonlocal hypotheses is done to expand the governing equations; furthermore, Hamilton’s principle is utilized to derive the equilibrium equations. Galerkin method is also employed to solve these equations. In addition, for the validation of those equations, the Navier’s method is used. The present research is, therefore, concerned with the effect of the main parameters, namely, external electric potential, external magnetic potential, in-plane mechanical force, elastic foundations, skew angle, and temperature change, on the rate of surface layers of the out-of-phase and in-phase vibration behavior of a skew DLMETE nanoplate. By increasing the skew angles, the in-phase and out-of-phase natural frequency ratios are shown to be converged; following a specific value of skew angle Ψ ≥ 70°, they overlap. By raising the skew angles, the effects of the van der Waals modulus on the vibration behavior are undermined. Therefore, the results of the present work could contribute to designing NEMS/MEMS components which make use of smart composite nanostructures.

Magneto-Thermo mechanical vibration analysis of FG nanoplate embedded on Visco Pasternak foundation

Article history:Received: 12 July 2018 Accepted: 1 September 2018 Available online In this paper, the mechanical vibration analysis of functionally graded (FG) nanoplate embedded in visco Pasternak foundation incorporating magnet and thermal effects is investigated. It is supposed that a uniform radial magnetic field acts on the top surface of the plate and the magnetic permeability coefficient of the plate along its thickness are assumed to vary according to the volume distribution function. The effect of in-plane pre-load, viscoelastic foundation, magnetic field and temperature change is studied on the vibration frequencies of functionally graded annular and circular nanoplate. Two different size dependent theories also are employed to obtain the vibration frequencies of the FG circular and annular nanoplate. It is assumed that a power-law model is adopted to describe the variation of functionally graded (FG) material properties. The FG circular and annular nanoplate is coupled by an enclosing viscoelastic medium which is simulated as a visco Pasternak foundation. The governing equation is derived for FG circular and annular nanoplate using the modified strain gradient theory (MSGT) and the modified couple stress theory (MCST). The differential quadrature method (DQM) and the Galerkin method (GM) are utilized to solve the governing equation to obtain the frequency vibration of FG circular and annular nanoplate. Subsequently, the results are compared with valid results reported in the literature. The effects of the size dependent, the in-plane pre-load, the temperature change, the magnetic field, the power index parameter, the elastic medium and the boundary conditions on the natural frequencies are scrutinized. According to the results, the application of radial magnetic field to the top surface of plate gives rise to change the state of stresses in both tangential and radial direction as well as the natural frequency. Also, The temperature changes play significant role in the mechanical analysis of FG annular and circular nanoplate. This study can be useful to product the sensors and devices at the nanoscale with considering the thermally and magnetically vibration properties of the nanoplate.

Anomalous Nernst effect and three-dimensional temperature gradients in magnetic tunnel junctions

Localized laser heating creates temperature gradients in all directions leading to three-dimensional electron flux in metallic materials. Temperature gradients in combination with material magnetization generate thermomagnetic voltages. The interplay between these temperature gradients and the magnetization along with their control enable to manipulate the generated voltages in magnetic nanodevices. We present a highly sensitive method to identify the anomalous Nernst effect generated on the nanometer length scale by micrometer-sized temperature gradients in magnetic tunnel junctions with CoFeB electrodes and a MgO tunnel barrier systematically extracted by analyzing the influence of in-plane temperature gradients on the tunnel magneto-Seebeck effect. This method yields an anomalous Nernst effect coefficient of KN ≈ 1.6 × 10−8 V T−1 K−1 for CoFeB. Generally, such investigations are motivated by utilizing otherwise wasted heat in magnetic memory devices for read/write operations. The additionally generated anomalous Nernst effect offers a functionality expansion, opening new application fields such as direction-dependent temperature sensing with downscaling potential.

Some effects of tool geometric features on friction stir weld response parameters

ABSTRACTPin geometries (shape, dimensions, and surface features) have significant effects on friction stir welding, dictating, to some extent, the material flow which in turn affects process variables and joint quality. In this paper, volumetric defect content and process response variables (in-plane forces, torque, power, and temperature) as a function of pin thread forms and features (thread/flat/flute) on mildly tapered conical pins were examined in AA6061-T6 for a range of welding parameters. The coarser thread pitch with different pin features performed better for producing good quality welds compared to finer threaded pins. Forge force requirements can be minimised using counter-flow flutes in threaded pin. Variations of nugget geometry, torque, power, and temperature were reported to correlate their dependence on pin features.

The hexaferrite Sr3Co2Fe24O41 thin films by chemical solution deposition method: Synthesis and characterization

Thin films of Sr3Co2Fe24O41 hexaferrite were prepared through the chemical solution deposition method using SrTiO3(1 1 1) single crystal substrates. The influence of the annealing temperature and annealing duration time on the phase composition, structural, microstructural and magnetic properties was investigated by examining the out- and in-plane crystallographic orientation, temperature and magnetic-field dependence of the magnetization, and surface topography. The Rietveld analysis performed on the XRD patterns indicates Sr3Co2Fe24O41 being the dominant phase, according to the XRD texture analysis the orientation relationship between Z ferrite and substrate can be expressed as (0 0 l)Z || (1 1 1)STO || and [1 1 0]Z || [1 0 0]STO. The magnetization data show anomalies in the magnetic behavior occurring at temperatures close to the room temperature that are characteristic for collinear to non-collinear spin structure transitions. The magnetic-field dependence of the magnetization proves soft magnetic character of ferrite film together with pronounced magnetic anisotropy, and shows a two-step increase of magnetization at lower fields (≤1 T) before it becomes almost saturated at around 2 T.

Nonequilibrium dynamic structure factor of a lipid bilayer in the presence of an in-plane temperature gradient.

There is rapidly increasing evidence that nanoscale temperature heterogeneities are involved in important biological processes. Combining nanoheating and nanoscale thermosensors forms the basis of emerging unique methods of cell therapy, tissue engineering, and regenerative medicine. Understanding corresponding phenomena seems to require a mesoscopic nonequilibrium hydrodynamic theory. In this paper, a Langevin-type model of dynamics of phonon modes propagating along a bilayer lipid membrane in the presence of an in-plane temperature gradient is proposed. Corresponding quantitative estimates for the Brillouin components of the nonequilibrium dynamic structure factor and the equal-time longitudinal momentum-density correlation function for a lipid bilayer are obtained. The analysis reveals that for typical values of parameters of lipid bilayer, the longitudinal temperature gradient of the order of 5qK for wave numbers q from 0.01 to 1nm^{-1} induces significant asymmetry of the Brillouin components of the dynamic structure factor and long-range spatial correlations in the plane of the bilayer. The corresponding membrane temperature gradients seem to be typical or achievable for cellular processes responsible for intracellular temperature variations and such external physical impacts as high-intensity electromagnetic pulses or heating of membrane-associated nanoparticles.

A novel approach to ambient energy (thermoelectric, piezoelectric and solar-TPS) harvesting: Realization of a single structured TPS-fusion energy device using MAPbI3

Organic-inorganic lead halide perovskite (MAPbI3) has shown remarkable photovoltaic performance along with unique properties such as ambipolar nature, ferroelectric and ultra-high Seebeck coefficient with low thermal conductivity. The exclusive properties of MAPbI3 enable to use as a fusion energy conversion material for harvesting of ambient energy such as the thermal, mechanical and solar energy. Many researchers have focused on each of these topics separately. This paper demonstrates a flexible single structured TPS-fusion energy device comprising of interdigitated electrodes (IDEs) and MAPbI3 to harvest thermal, mechanical and solar energy. A TPS-device is individually operated as a thermoelectric, piezoelectric, and solar (TPS)-energy harvester by independently applying a thermal gradient, mechanical force and solar energy. The TPS-device as a thermoelectric generator is exhibited the higher thermoelectric output performance in in-plane temperature gradient than out-of-plane temperature gradient. The obtained piezoelectric output values of the TPS-device as a piezoelectric generator under periodic applied pressure are 1.47 V and 0.56 µA. The TPS-based photovoltaic device is generated an open-circuit voltage of 0.77 V and a short-circuit current density of 0.022 mA/cm2. This conceptual demonstration of fusion energy harvesting device using IDE-based structure with light active ambipolar material could introduce innovative approaches in fusion-conversion energy technology.

Electrical nucleation and detection of single 360° homochiral Néel domain walls measured using the anomalous Nernst effect

Using a thermoelectric measurement, we demonstrate the nucleation and detection of a single 360° homochiral Néel domain wall (DW), formed by an independently nucleated pair of 180° Néel DWs having the same helicity in a perpendicular magnetic anisotropy track. The DW formation is governed by strong interfacial Dzyaloshinskii-Moriya interaction (DMI) and detected at room temperature using the anomalous Nernst effect (ANE). A large DMI can be generated at an interface where the symmetry is broken between a material having a large spin-orbit coupling and a thin ferromagnetic layer. The ANE voltage, VANE∝∇T×M, is sensitive to the magnitude of the out-of-plane magnetization M through a confined in-plane temperature gradient ∇T and allows for the direct thermoelectrical detection of the DW position with nanoscale accuracy along the track. Here, we present evidence that independently nucleated pairs of 180° Néel DWs in microwire devices can be brought together by an applied magnetic field to form a 360° homochiral Néel DW. Subsequently, we show that a strong magnetic field needs to be applied in order to annihilate the 360° DW due to the strong interfacial DMI in our Pt/Co(0.6nm)/AlOx multilayers. In addition to enabling a high magnetic storage and data transfer rate with low power consumption in novel computational and storage devices, such DWs facilitate a reduction in bit size down to a few nanometers with metastability.

Defining Photovoltaic Mission Profile for the Pre-Design of Static Converters

A methodology is presented for accurately defining the mission profile and relevant operating conditions of photovoltaic systems. The proposed method works as a tool for obtaining useful information for designing high-efficiency and reliable photovoltaic power converters. This methodology enables modern design techniques of pre-sizing and optimizing power converters according to its mission profile and relevant operating conditions. Two cities in different climate zones were analyzed and compared, wherein a large dataset of solar irradiance and ambient temperature from each location was used. Meteorological measurements from ten years were used to obtain an average typical year of weather conditions for both cities. In-plane irradiance on photovoltaic panels for an annual operation was estimated. A mathematical model was used to analyze solar incidence on modules in fix mounting and with the use of mechanical trackers. A photovoltaic system's operating current, voltage, and temperature levels were estimated in relationship to in-plane irradiance and ambient temperature. Energy yield throughout one year was obtained based on the average typical weather condition. An analysis is presented regarding how climate affects photovoltaic operation and what are the most relevant current and voltage levels for each mission profile; these levels are the starting point for an accurate converter design. Validation results of photovoltaic modeling are presented for a fourteen-panel system of 3.29 kW installed capacity. The impact of using mechanical trackers on power processing is also presented. A discussion is made on the importance of previous knowledge of an accurate photovoltaic mission profile on the design of power converters and on maximizing energy processing.

Unidirectional Spin-Wave-Propagation-Induced Seebeck Voltage in a PEDOT:PSS/YIG Bilayer

We clarify the physical origin of the dc voltage generation in a bilayer of a conducting polymer film and a micrometer-thick magnetic insulator Y_{3}Fe_{5}O_{12} (YIG) film under ferromagnetic resonance and/or spin wave excitation conditions. The previous attributed mechanism, the inverse spin Hall effect in the polymer [Nat. Mater. 12, 622 (2013)NMAACR1476-112210.1038/nmat3634], is excluded by two control experiments. We find an in-plane temperature gradient in YIG which has the same angular dependence with the generated voltage. Both vanish when the YIG thickness is reduced to a few nanometers. Thus, we argue that the dc voltage is governed by the Seebeck effect in the polymer, where the temperature gradient is created by the nonreciprocal magnetostatic surface spin wave propagation in YIG.

Temperature dependence of exchange bias in (NiFe/IrMn)n multilayer films studied through static and dynamic techniques

The in-plane temperature dependence of exchange bias was studied through both dc magnetometry and ferromagnetic resonance spectroscopy in a series of [NiFe/IrMn]n multilayer films, where n is the number of layer repetitions. Major hysteresis loops were recorded in the temperature range of 300 K to 2 K to reveal the effect of temperature on the exchange bias in the static regime while temperature-dependent continuous-wave ferromagnetic resonance for frequencies from 3 to 16 GHz was used to determine the exchange bias dynamically. Strong divergence between the values of exchange bias determined using the two different types of measurements as well as a peak in temperature dependence of the resonance linewidth were observed. These results are explained in terms of the slow-relaxer mechanism.

Hygrothermal wave propagation in viscoelastic graphene under in-plane magnetic field based on nonlocal strain gradient theory

A size-dependent model is developed for the hygrothermal wave propagation analysis of an embedded viscoelastic single layer graphene sheet (SLGS) under the influence of in-plane magnetic field. The bi-Helmholtz nonlocal strain gradient theory involving three small scale parameters is introduced to account for the size-dependent effects. The size-dependent model is deduced based on Hamilton's principle. The closed-form solution of eigenfrequency relation between wave number and phase velocity is achieved. By studying the size-dependent effects on the flexural wave of SLGS, the dispersion relation predicted by the developed size-dependent model can show a good match with experimental data. The influence of in-plane magnetic field, temperature and moisture of environs, structural damping, damped substrate, lower and higher order nonlocal parameters and the material characteristic parameter on the phase velocity of SLGS is explored.

Anomalous Nernst effect in Ir22Mn78/Co20Fe60B20/MgO layers with perpendicular magnetic anisotropy

The anomalous Nernst effect in a perpendicularly magnetized Ir22Mn78/Co20Fe60B20/MgO thin film is measured using well-defined in-plane temperature gradients. The anomalous Nernst coefficient reaches 1.8 μV/K at room temperature, which is almost 50 times larger than that of a Ta/Co20Fe60B20/MgO thin film with perpendicular magnetic anisotropy. The anomalous Nernst and anomalous Hall results in different sample structures revealing that the large Nernst coefficient of the Ir22Mn78/Co20Fe60B20/MgO thin film is related to the interface between CoFeB and IrMn.

Hybrid ultrasound-MR guided HIFU treatment method with 3D motion compensation.

Treatments using high-intensity focused ultrasound (HIFU) in the abdominal region remain challenging as a result of respiratory organ motion. A novel method is described here to achieve 3D motion-compensated ultrasound (US) MR-guided HIFU therapy using simultaneous ultrasound and MRI. A truly hybrid US-MR-guided HIFU method was used to plan and control the treatment. Two-dimensional ultrasound was used in real time to enable tracking of the motion in the coronal plane, whereas an MR pencil-beam navigator was used to detect anterior-posterior motion. Prospective motion compensation of proton resonance frequency shift (PRFS) thermometry and HIFU electronic beam steering were achieved. The 3D prospective motion-corrected PRFS temperature maps showed reduced intrascan ghosting artifacts, a high signal-to-noise ratio, and low geometric distortion. The k-space data yielded a consistent temperature-dependent PRFS effect, matching the gold standard thermometry within approximately 1°C. The maximum in-plane temperature elevation ex vivo was improved by a factor of 2. Baseline thermometry acquired in volunteers indicated reduction of residual motion, together with an accuracy/precision of near-harmonic referenceless PRFS thermometry on the order of 0.5/1.0°C. Hybrid US-MR-guided HIFU ablation with 3D motion compensation was demonstrated ex vivo together with a stable referenceless PRFS thermometry baseline in healthy volunteer liver acquisitions. Magn Reson Med 79:2511-2523, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Dependence of anomalous Nernst effect on crystal orientation in highly ordered γ′-Fe4N films with anti-perovskite structure

The anomalous Nernst effect (ANE) in highly ordered Fe4N films was examined in the measurement configuration with an in-plane temperature gradient (∇Tx). The anomalous Nernst coefficient (Qs) in the case of ∇Tx ∥ Fe4N[110] was clearly larger than that in the case of ∇Tx ∥ Fe4N[100]. Note here that no reports on the Qs in Fe4N films have been presented. This anisotropic Qs (Qani) was also observed in a different configuration with an out-of-plane temperature gradient. Unlike Fe4N, pure Fe and A2-FeAl systems showed a negligible Qani. This Qani might be attributed to the specific hybridization effects between the 3d orbitals of Fe and the 2p orbitals of N.

Thermal buckling and postbuckling of functionally graded graphene-reinforced composite laminated plates resting on elastic foundations

This paper presents the modeling and analysis for the thermal postbuckling of graphene-reinforced composite laminated plates resting on an elastic foundation and subjected to in-plane temperature variation. A micromechanical model is used to estimate the temperature-dependent material properties of the graphene-reinforced composites (GRCs). Piece-wise functionally graded (FG) GRC layers along the thickness direction of a plate is considered in this study. Employing the higher order shear deformation plate theory, the governing equations for FG-GRC plates are derived and the effects of plate-foundation interaction and temperature variation are included in the modeling. A two-step perturbation technique is applied to obtain the buckling temperature and the thermal postbuckling load-deflection curves for perfect and imperfect FG-GRC laminated plates. The results show that the buckling temperature as well as thermal postbuckling strength of the plates can be increased as a result of the functionally graded graphene reinforcement for the plates.