Thermal transport in beta-gallium oxide thin-film using non-gray Boltzmann transport equation

Phonon transport in β-Ga2O3 thin films and metal–oxide field effect transistors (MESFETs) are investigated using non-gray Boltzmann transport equations (BTE) to decipher the effect of ballistic-diffusive phonon transport. The effects of domain size, and energy dissipation to various phonon modes and subsequent phonon-phonon energy exchange on the thermal transport and temperature distribution is investigated using non-gray BTE. Our analysis deciphered that domain size plays a major role in thermal transport in β-Ga2O3 but energy dissipation to various phonon modes and subsequent phonon-phonon energy exchange does not affect the temperature field significantly. Phonon transport in β-Ga2O3 MESFETs on diamond substrate is investigated using coupled non-gray BTE and Fourier model. It is established that the ballistic effects need to be considered for devices with β-Ga2O3 layer thickness less than 1 µm. A non-gray phonon BTE model should be used near hotspot in the thin β-Ga2O3 layer as the Fourier model may not give accurate temperature distribution. The results from this work will help in understanding the mechanism of phonon transport in the β-Ga2O3 thin films and energy efficient design of its FETs.

Analytical Investigation of Non-Fourier Bio-Heat Transfer in the Axisymmetric Living Tissue Exposed to Pulsed Laser Heating Using Finite Integral Transform Technique

The present article proposed the closed-form solution of the generalized non-Fourier model-based bio-heat transfer equation (BHTE) in Cylindrical coordinates to understand the thermal behavior of living tissue heated by a pulsed laser. The axisymmetric living tissue exposed to the non-Gaussian temporal profile of laser heating has been considered to investigate the non-Fourier bio-heat transfer phenomena. The closed-form solution of the generalized non-Fourier model-based BHTE with time-dependent thermal energy generation has been obtained through the finite integral transform technique. The analytical solution was juxtaposed to the corresponding numerical solution in order to determine its reliability. The numerical solution of the aforementioned governing equation has been obtained by the finite volume method. The results of both analytical and numerical solutions have been verified using results given in published literature. Subsequently, the dual-phase-lag model's findings were juxtaposed to those obtained using the hyperbolic and traditional Fourier models. The effect of different parameters like relaxation times corresponding to the temperature gradient and heat flux, metabolic energy generation, and blood perfusion on the resultant temperature distribution inside the axisymmetric living tissue exposed to pulsed laser heating has been discussed. The importance of the present study might be found in various applications such as laser-based-photo-thermal therapy, melting of the surface of metal and alloys by laser heating, etc.

Modeling Wind Speed with a Long-Term Horizon and High-Time Interval with a Hybrid Fourier-Neural Network Model

The limited availability of local climatological stations and the limitations to predict the wind speed (WS) accurately are significant barriers to the expansion of wind energy (WE) projects worldwide. A methodology to forecast accurately the WS at the local scale can be used to overcome these barriers. This study proposes a methodology to forecast the WS with high-resolution and long-term horizons, which combines a Fourier model and a nonlinear autoregressive network (NAR). Given the nonlinearities of the WS variations, a NAR model is used to forecast the WS based on the variability identified with the Fourier analysis. The NAR modelled successfully 1.7 years of wind-speed with 3 hours of the time interval, what may be considered the longest forecasting horizon with high resolution at the moment.

Measurement of five-degrees-of-freedom spindle error motion using multi probe error separation

Herein, a precision measurement method is proposed to evaluate the radial, axial, and tilt error motions of rotating devices such as precision spindles. To improve the accuracy of the estimated multiple-degree-of-freedom error motion components, form error signals in the runout signals are separated and precompensated for before the calculation of the five-degrees-of-freedom error motion components. Fourier model-based multi probe error separation (MPES) techniques, which can prevent the occurrence of harmonic distortions, are applied to separate the form error signals. A three-probe method is applied to layers on the side surface of the cylindrical artifact, and a modified two-probe method is developed and applied to the upper surface. The radial, tilt, and axial error motions are calculated using the runout signals that do not contain the separated form error signals. The measurement system uses eight capacitive probes to detect the runout signals of the cylindrical artifact mounted at the center of the rotating device. To compare the proposed method with the five-probe-based conventional measuring method, an evaluation test simulation is conducted repeatedly five times. Results indicate that the proposed MPES method calculated the uncertainty using the deviation between the computed results from the existing and novel methods; additionally, the input signal in terms of the radial, tilt (layers 1 and 2), and axial error motions are [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively. It is confirmed that the undesirable effects of the form error signals are successfully removed and that the accuracies of the measured spindle error motion components improve.

MicroRNA-431 Promotes Progress of Breast Cancer by Aiming Rejection Targeting Molecule A and Activating Epithelial-Mesenchymal Transition

Objective: To conduct mathematical expression of the law of internal fascicular groups of peripheral nerves in spatial extension, so as to reveal the universal law of fascicular groups during the process of spatial extension. Methods: The centroid of each fascicular group shown on each Micro-CT image of the peripheral nerves was extracted, and these centroids were connected to form the centroid space curve of each fascicular group respectively based on preliminary studies. Results: The mean value of relative offset of fascicular groups in space was 3.7 μm while its maximum was: when a distance of 5 μm was extended, the fascicular groups centroid would have an offset of 21.4 μm. The accuracy of fitting of the centroid spatial curve of the fascicular groups using the 4th-order Fourier model could be up to 98%. Each parameter in the model obeyed the t distribution with position/dimension parameters. The dimension of parameters in the 1st-order component was obviously greater than that of the components of the other orders, indicating that the probability density function of harmonic component parameter showed an obvious peak shape. Conclusions: The centroid space curve of the Fascicular groups could express the extension of fascicular groups in space truly and exactly. The extension process of fascicular groups in space could be expressed accurately by the 4th-order Fourier model. The reason for using the 4th-order model was that a better balance could be obtained in model complexity and accuracy of fitting.

Centroid of Fascicular Groups in Micro-CT Image of Peripheral Nerves

Objective: To conduct mathematical expression of the law of internal fascicular groups of peripheral nerves in spatial extension, so as to reveal the universal law of fascicular groups during the process of spatial extension. Methods: The centroid of each fascicular group shown on each Micro-CT image of the peripheral nerves was extracted, and these centroids were connected to form the centroid space curve of each fascicular group respectively based on preliminary studies. Results : The mean value of relative offset of fascicular groups in space was 3.7 m while its maximum was: when a distance of 5 m was extended, the fascicular groups centroid would have an offset of 21.4 m. The accuracy of fitting of the centroid spatial curve of the fascicular groups using the 4th-order Fourier model could be up to 98%. Each parameter in the model obeyed the t distribution with position/dimension parameters. The dimension of parameters in the 1st-order component was obviously greater than that of the components of the other orders, indicating that the probability density function of harmonic component parameter showed an obvious peak shape. Conclusions: The centroid space curve of the Fascicular groups could express the extension of fascicular groups in space truly and exactly. The extension process of fascicular groups in space could be expressed accurately by the 4th-order Fourier model. The reason for using the 4th-order model was that a better balance could be obtained in model complexity and accuracy of fitting.

Stress behaviour across human tooth by temperature gradient resulting of laser irradiation

The authors report the simulation of temperature distribution and thermally induced stress in the premolar tooth under ND-YAG pulsed laser beam. The Three-Phase-Lag (TPL) non-Fourier model is proposed to describe the heat conduction in the human tooth with nonhomogeneous inner structures. A premolar tooth comprising enamel, dentin, and pulp with real shapes and thicknesses are considered and a numerical method of finite difference was adopted to solve the time-dependent TPL bio-heat transfer, strain and stress equations. The surface heating scheme is applied for simulation of laser therapy. The aim of this laser therapy is that the temperature of pulp reaches to 47oC. The results are achieved as a function of laser heat flux showed when laser beam is irradiated downward (from the top of the tooth), the temperature and thermally induced stress increase as a function of time. The temperature increment is high on the top layers of tooth that is a result of strong absorption of beams by enamel. The thermal stress and strain in the enamel and dentin layers are more than the pulp layer that is a result of weak thermal expansion of them proportional to the pulp layer.