Junction size dependence of the heat controlled magnetic anisotropy in magnetic tunnel junctions

We investigated the heat controlled magnetic anisotropy (HCMA) in magnetic tunnel junctions with various junction sizes. We evaluated the HCMA from perpendicular magnetic anisotropy under a direct current voltage measured by the spin-torque diode technique. The maximum HCMA magnitude of 5.4 μJ (Wm)−1 was observed, and the HCMA increased with increasing diameter. Our results can be explained by a simple heat dissipation model and suggest that the in-plane heat current affects HCMA.

Numerical Investigation Into the Effect of Air Swirl on Non-Premixed Combustion

Endeavour is made to investigate the effect of swirled air on methane-air combustion in a Harwell combustor geometry. The inlet air swirl intensity on combustion characteristics such as temperature, pollutant formation, and flow dynamics is studied. The modeling of turbulent characteristics is performed with the standard K–ε model using ANSYS Fluent. Eddy dissipation model with one step reaction is used for modeling chemical reaction and P-I radiation model for radiation heat transfer. The swirl number is achieved in the range of 0.0 to 0.6, by varying the tangential velocity to the air inlet. With the increase in swirl intensity, the maximum flame temperature drops, and most of the flame formation shifts towards the inlet of the furnace. The change in the flow field is aided by the formation of recirculating bubbles. The swirl causes the flame to spread radially away from the axis, thereby increasing the heat transfer flux to the furnace wall. As a result, a significant reduction in the formation of NO pollutants is observed.

Research computer numerical simulation on heat dissipation model of submarine data centre based on TOPSIS model

Due to the huge energy consumption of land-based data centers, it is necessary to establish undersea data centers as soon as possible in order to alleviate the problem of resource tension. In this paper, the uniformity of containers is assumed. Through force analysis, it is found that the stress of containers is uniformly distributed, so only the external stress should be considered. Hypothesis submarine data center in the 50 m deep seawater, calculate the container need to withstand stress is 76.417403 Mpa, common material in engineering field, then physical parameters of material to deal with the dimensional and normalization, and establishes a comprehensive evaluation model material, the Topsis method is adopted to solve, to solve the optimal evaluation of the results can be divided into: 7-4 PH Stainless Stee 0.7450 points, so choose it as IU server container material.

Intensification of liquid mixing and local turbulence using a fractal injector with staggered conformation

Two self-similar, tree-like injectors of the same fractal dimension are compared, demonstrating that other geometric parameters besides dimension play a crucial role in determining mixing performance. In one injector, when viewed from the top, the conformation of branches is eclipsed; in the other one, it is staggered. The flow field and the fractal injector induced mixing performance are investigated through computational fluid dynamics (CFD) simulations. The finite rate/eddy dissipation model (FR/EDM) is modified for fast liquid-phase reactions involving local micromixing. Under the same operating conditions, flow field uniformity and micromixing are improved when a staggered fractal injector is used. This is because of enhanced jet entrainment and local turbulence around the spatially distributed nozzles. Compared with a traditional double-ring sparger, a larger reaction region volume and lower micromixing time are obtained with fractal injectors. Local turbulence around the spatially distributed nozzles in fractal injectors improves reaction efficiency.

Fretting Wear Mechanical Analysis of Double Rough Surfaces Based on Energy Method

A fretting wear model of rough surface that conforms to the actual situation is established to accurately reveal the wear mechanism of the connection structure. In the ABAQUS software, the UMESHMOTION subroutine and the energy dissipation model are used to simulate the fretting wear of double rough surfaces. The new model, a single rough surface model, and a smooth model are compared to analyze the differences between them. In addition, the influence of surface roughness, material, and friction coefficient on the fretting wear of rough surfaces is systematically explored through finite element simulation. The results show that the reliability of the model has been verified through Hertz’s theory and experiments. The stress and wear of the contact surface are more realistically reflected by the double roughness model. Besides, with the increase of surface roughness and material rigidity and the decrease of friction coefficient, the wear of the double rough surface model becomes more severe. The research work provides a theoretical basis for the design and performance prediction of the connection structure.

Investigation of pollutants formation in a diesel engine using numerical simulation

The current study aims at simulating the in-cylinder combustion process in a diesel engine and investigating the engine performance and pollutant formation. The combustion simulation is performed on a 3D sector employing appropriate models for various physical and chemical processes contributing in the combustion phenomenon. The overall model includes Transition SST turbulence model, eddy dissipation model for turbulence chemistry interaction, Moss–Brookes model for soot calculation and Zeldovich mechanism for NO production other than the usual transport equations. The numerical solutions are based on the finite volume discretization of the governing partial differential equations. Engine performance has been studied in terms of pressure, temperature and heat release rate while the pollutants formation has been investigated in terms of soot and thermal NO production. The results show that the ignition delay is quite short and that the injection timing may be successfully employed to control the combustion behavior. The simulation results are quite consistent with the expected behavior of the target variables indicating that the CFD analysis can be successfully employed in the diesel engine design. The results validation may be acknowledged in view of the mesh independence test, literature comparison and justification of the models.

An Improved Nonlinear Cumulative Damage Model Considering the Influence of Load Sequence and Its Experimental Verification

According to the change characteristics in the toughness of the metal material during the fatigue damage process, the fatigue tests were carried out with the standard 18CrNiMo7-6 material. Scanning the fracture with an electron microscope explains the lack of linear cumulative damage in the mechanism. According to the obtained results, a nonlinear damage accumulation model which considered the loading sequence state under the toughness dissipation model was established. The recursive formula was devised under two-level. The fatigue test data verification of three metal materials showed that using this model to predict fatigue life is satisfactory and suitable for engineering applications.

Quantum Euler Relation for Local Measurements

In classical thermodynamics the Euler relation is an expression for the internal energy as a sum of the products of canonical pairs of extensive and intensive variables. For quantum systems the situation is more intricate, since one has to account for the effects of the measurement back action. To this end, we derive a quantum analog of the Euler relation, which is governed by the information retrieved by local quantum measurements. The validity of the relation is demonstrated for the collective dissipation model, where we find that thermodynamic behavior is exhibited in the weak-coupling regime.