Thermal dynamics and electronic temperature waves in layered correlated materials

Understanding the mechanism of heat transfer in nanoscale devices remains one of the greatest intellectual challenges in the field of thermal dynamics, by far the most relevant under an applicative standpoint. When thermal dynamics is confined to the nanoscale, the characteristic timescales become ultrafast, engendering the failure of the common description of energy propagation and paving the way to unconventional phenomena such as wave-like temperature propagation. Here, we explore layered strongly correlated materials as a platform to identify and control unconventional electronic heat transfer phenomena. We demonstrate that these systems can be tailored to sustain a wide spectrum of electronic heat transport regimes, ranging from ballistic, to hydrodynamic all the way to diffusive. Within the hydrodynamic regime, wave-like temperature oscillations are predicted up to room temperature. The interaction strength can be exploited as a knob to control the dynamics of temperature waves as well as the onset of different thermal transport regimes.

An efficient local imaging strategy based on illumination analysis with deep learning

We propose a deep-learning-based illumination analysis and efficient local imaging method. Based on the wavefield forward modeling, seismic illumination can intuitively express the energy propagation of direct waves, reflected waves, and transmitted waves, while it requires high calculation costs. We use a series of convolution operations in deep learning to establish the nonlinear relationship between the model and the illuminations to realize single-shot illumination result of the model. Stacking the single shot illumination results obtained by the network prediction can further help determine the target area. For the target area, we use a deep learning method to obtain the low illumination area of the geological model. Each shot has contribution to the low illuminated area; single shot is selected based on the contribution of the shot being greater than the average illuminance, and the low illumination area is imaged by reverse time migration on the selected shot gather. The trained convolutional neural network can help us quickly obtain the single shot illumination result of the model, which is convenient to analyze the energy distribution of various areas of geological model, and do further imaging for target areas. Using part of the shot gathers to image a local area can recover the complex geological structure of the area and improve the efficiency of reverse time migration especially for 3D problems. This method has universal applicability and is suitable for local imaging of various complex models such as subsalt areas and deep regions.

Numerical Approximation of Microorganisms Hybrid Nanofluid Flow Induced by a Wavy Fluctuating Spinning Disc

The analysis explored a numerical simulation of microorganisms, carbon nanotubes (CNTs) and ferric oxide water-based hybrid nanofluid flow induced by a wavy fluctuating spinning disc with energy propagation. In the presence of CNTs and magnetic nanoparticulates, the nanofluid is synthesized. The exceptional tensile strength, flexibility, and electrical and thermal conductivity of carbon nanotubes and iron nanoparticles have been extensively reported. The motive of the proposed analysis is to optimize thermal energy conveyance efficiency for a spectrum of industrial and biomedical applications. The phenomena have been expressed as a system of partial differential equations (PDEs) which contain the momentum, energy, concentration, and motile microorganism equations. The modeled equations have been diminished to the dimensionless system of nonlinear ODEs through a similarity framework. The Matlab built-in package boundary value solver has been utilized to solve the obtained system of ODEs. The findings are compared to the PCM technique for validity purposes. The results are illustrated graphically and discussed. The layout of a rotating disc has a positive effect on energy transition and velocity profile. The irregular rotating surface increases energy progression up to 15% relative to a smooth surface. The accumulation of nanocomposites (CNTs and magnetic nanoparticles) significantly enhanced the thermal capabilities of the liquid medium. When operating with a low distribution, it is more impactful.

Energetics and Kinematics of Inertial Oscillations in the Central Northern GOM

Understanding the physics of generation, propagation, and dissipation of inertial currents is important from a variety of aspects. For the Gulf of Mexico, one such aspect is that these oscillations represent an uncertainty in the measurements and forecasting of the longer-period currents, such as those due to the Loop Current (LC) and meso-scale eddies. The Industry has a practice of applying an ‘uplift’ to estimates of current velocity to account for the effect of tidal and inertial currents in cases when observations or model estimates do not resolve the high-frequency current variability. The value of the ‘uplift’ is assumed to be proportional to the intensity of the low-frequency flow. Our analysis aims at testing whether this assumption is valid by providing a detailed description of the space-time variability, including seasonal changes, of inertial oscillations in the central northern Gulf of Mexico. From the analysis of long-term current profile observations and drifter data we found that, on average, near-inertial oscillations have higher amplitudes outside of the areas of strong low-frequency currents associated with a Loop Current Eddy (LCE). Within the upper 200m of the water column, periods characterized by the downward energy propagation dominate. In the layer below 200m, near-inertial waves propagate upward and downward, and the wave trains cannot be traced to a single source of energy. This suggests near-inertial waves within the main part of the water column are of ‘global’ rather than of ‘local’ origin. For most near-inertial wave generation events through wind forcing, the downward energy propagation could not be traced for any extended period of time and no deeper than approximately 200-m depth. The rate of downward energy propagation in the upper pycnocline is on the order of 10-12 m/day. For the near-inertial currents, the first two Empirical Orthogonal Functions (EOF) contribute only 40% into the total current variability for the period of LCE presence and 52% for the period of benign current conditions. The mode shapes vary within a wide range that, most likely, reflects a random distribution of mode shapes that depend on the lateral geometry of the forcing, mixed layer depth, and stratification.

Ballistic Heat Transport in Nanocomposite: The Role of the Shape and Interconnection of Nanoinclusions

In this article, the effect on the vibrational and thermal properties of gradually interconnected nanoinclusions embedded in an amorphous silicon matrix is studied using molecular dynamics simulations. The nanoinclusion arrangement ranges from an aligned sphere array to an interconnected mesh of nanowires. Wave-packet simulations scanning different polarizations and frequencies reveal that the interconnection of the nanoinclusions at constant volume fraction induces a strong increase of the mean free path of high frequency phonons, but does not affect the energy diffusivity. The mean free path and energy diffusivity are then used to estimate the thermal conductivity, showing an enhancement of the effective thermal conductivity due to the existence of crystalline structural interconnections. This enhancement is dominated by the ballistic transport of phonons. Equilibrium molecular dynamics simulations confirm the tendency, although less markedly. This leads to the observation that coherent energy propagation with a moderate increase of the thermal conductivity is possible. These findings could be useful for energy harvesting applications, thermal management or for mechanical information processing.

The Horseshoe Abyssal plain Thrust could be the source of the 1755 Lisbon earthquake and tsunami

The southwest Iberia margin is widely believed to have hosted the 1755 Great Lisbon earthquake and ensuing tsunami, one of the most destructive natural events in European history. Here we combine geophysical data and numerical tsunami modelling to investigate the source and mechanism responsible for this event. We find that an intra-plate, lithospheric¬-scale thrust fault located at the Horseshoe Abyssal Plain coincides with the location and focal mechanisms of the largest regional earthquakes and is likely to have suitable dimensions and fault-rock properties to account for the magnitude of the 1755 event. We present tsunami simulations with this fault as the source, and find that they reproduce reported tsunami energy propagation patterns, arrival-times and run up heights more successfully than other modelled sources. We propose that a reverse dip-slip mechanism on the northwest verging Horseshoe Abyssal plain Thrust, combined with the two-state mechanical behaviour of serpentinite, is the most likely candidate for the source of the 1755 Great Lisbon earthquake and for other recent large regional earthquakes.

Influence of Acoustic Black Hole Array Embedded in a Plate on Its Energy Propagation and Sound Radiation

The plate embedded with acoustic black hole (ABH) indentations is potential for structural vibration and noise control. This work focuses on the mid- and low-frequency performance of plates embedded with the array of ABH for energy focalization and vibration & noise suppression. Plates embedded with two-dimensional ABHs are modelled with detailed Finite Element (FE) models, and the power flow method is introduced to analyze the energy propagation characteristics arising from ABH effect. Then the distribution of average vibration power density along ABH radius is studied. Next, the energy dissipation effects of the plate model embedded with ABH array with two types of damping layers are investigated. Finally, the sound pressure levels of the ABH structure are calculated and discussed. This work is helpful to understand the characteristics of plates embedded with ABH array in reducing vibration and noise radiation. Results show the tremendous potential of ABH array for vibration and noise control.

The Impact of High-Energy Mining-Induced Tremor in a Fault Zone on Damage to Buildings

Seismic energy propagation from the hypocentre of mining-induced tremors usually causes an uneven distribution of the peak ground velocity PGVHmax in tectonically complicated structures, and consequently, an uneven distribution of damage to buildings located on the ground surface. This study aimed to estimate the impact of high-energy mining-induced tremors in fault zones on damage to buildings. In the study, we describe a case of one of the highest-energy mining-induced tremors E = 4.0 · 108 J (local magnitude ML = 3.6) that occurred in the Upper Silesian Coal Basin (USCB), Poland. The hypocentre of the tremor was most probably located in the Barbara fault zone, one of the larger faults in that western part of the USCB. Numerous damaged buildings on the terrain surface were registered, both in the epicentral zone and at a greater distance from the epicentre, mostly from the southern side of the Barbara fault zone. We calculated that the tremor was characterised by a normal slip mechanism associated with the same kind of fault as the Barbara fault. The azimuth of the nodal planes was similar to the west-east direction, which is consistent with the azimuth of the Barbara fault. From the focal mechanism, the greatest propagation of seismic energy occurred in south and west-east directions from the tremor hypocentre towards the surface. It was found that from the northern side of the hanging wall of the Barbara fault, there were 14 instances of damage (19%), and in the southern part of a hanging wall, there were 58 (81%). Therefore, the directionality of seismic energy propagation is aligned with the focal mechanism acting in the Barbara fault. It has also been concluded that a width of the zone of up to about 1200 m along the Barbara fault is the most threatening on the basis of registered building damage in the geological conditions of USCB. The study has shown that in assessing the impact of mining-induced tremors on buildings and the environment, the disturbance of seismic energy propagation by larger faults should be considered.