3D MHD simulation of a pulsationally-driven MRI decretion disc

We explore the pulsationally driven orbital mass ejection mechanism for Be star disc formation using isothermal, 3D magnetohydrodynamic (MHD) and hydrodynamic simulations. Non-radial pulsations are added to a star rotating at 95 per cent of critical as an inner boundary condition that feeds gas into the domain. In MHD, the initial magnetic field within the star is weak. The hydrodynamics simulation has limited angular momentum transport, resulting in repeating cycles of mass accumulation into a rotationally-supported disc at small radii followed by fall-back on to the star. The MHD simulation, conversely, has efficient (Maxwell αM ∼ 0.04) angular momentum transport provided by both of turbulent and coherent magnetic fields; a slowly decreting midplane driven by the magnetorotational instability and a supersonic wind on the surface of the disc driven by global magnetic torques. The angle and time-averaged properties near the midplane agree reasonably well with a 1D viscous decretion disc model with a modified $\tilde{\alpha }=0.5$, in which the gas transitions from a subsonic thin disc to a supersonic spherical wind at the critical point. 1D models, however, cannot capture the multi-phase decretion/angular structure seen in our simulations. Our results demonstrate that, at least under certain conditions, non-radial pulsations on the surface of a rapidly rotating, weakly magnetized star can drive a Keplerian disc with the basic properties of the viscous decretion disc paradigm, albeit coupled to a laminar wind away from the midplane. Future modeling of Be star discs should consider the possible existence of such a surface wind.

Energy wood production by disk cutting machines with different methods of chip emission

The article describes the methodology of physical and mathematical modeling of the mechanism for ejection of chips of a disk chipper. This technique allows you to calculate and optimize the design and technological parameters of the chip ejection mechanism. To accomplish this task, the flow of chip elements was divided into separate spherical elements, and the working surfaces of the chip ejection mechanism are represented by a set of fragments of planes conjugated to each other. When creating a mathematical model for calculating and optimizing the design and technological parameters of the chip ejection mechanism, the following indicators of the efficiency of the chip ejection mechanism were analyzed: the rate of chip ejection at the exit of the chipping line, the probability of chip ejection from the first revolution of the chipping disk, the mechanical power consumed for the ejection of chips after the stage of crushing the cut residues knives. The mathematical model is implemented in a computer program in the Object Pascal language in the Delphi 7 development environment. The program allows carrying out computer experiments to analyze the movement in the casing and chipping of chips obtained from felling residues and to study the effect of the design and technological parameters of the ejection mechanism on the efficiency of the disk chipper. The computer studies carried out made it possible to determine the best numerical ranges of the chipping disk rotation frequency and the number of blades located on the chipping disk. The likelihood of chip entrainment at the first revolution of the chipping disk and the power consumption for the ejection of chips from the disk chipper were also determined.

Laser Treatment CVD Diamond Coated Punch for Ultra-Fine Piercing of Metallic Sheets

CVD-diamond coated special tools have been widely utilized to prolong their tool life in practical production lines. WC (Co) punch for fine piercing of metallic sheets required for high wear-toughness to be free from chipping and damages and for high product quality to punch out the holes with sufficient dimensional accuracy. The laser trimming process was developed to reduce the surface roughness of diamond coating down to submicron level and to adjust its diamond layer dimensions with a sharp punch edge for accurate piercing. The pulsed laser irradiation was employed to demonstrate that micro-groove was accurately formed into the diamond coating. Less deterioration in the worked diamond film by this laser treatment was proved by the Raman spectroscopy. The femtosecond laser trimming was proposed to sharpen the punch edge down to 2 μm and to form the nano-textured punch side surfaces with the LIPSS (Laser Induced Periodic Surface Structuring)-period of 300 nm. Fine piercing experiments were performed to demonstrate that punch life was significantly extended to continuous punching in more than 10,000 shots and that mirror-shining hole surfaces were attained in every shot by regularly coining the nanotextures. The sharp punch edge with homogeneous edge profile was responsible for reduction of the induced damages into work sheet by piercing. The punch life was extended by the ejection mechanism of debris particles through the nanotextures on the punch side surface. The present laser treatment was useful in trimming and nanostructuring the complex-shaped punch edge for industrial application.

The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

The composition of outer drop layers has been associated with distinct chemical reactivity. We use atomistic modeling to examine how the composition of the surface excess charge layer (SECL) is related to the ejection mechanisms of ions. Even though the drop disintegration is inherently a non-equilibrium process we find that the equilibrium ion distribution in SECL predicts the ions that are ejected. The escape of the ions in aqueous drops takes place from conical protrusions that are global drop deformations and their appearance is independent of the location of a single ion. Our results are consistent with the equilibrium partition model, which associates the mass spectrum with the distribution of analytes in the drop’s double electric layer. We present evidence that atomistic simulations of minute nano-drops cannot distinguish Rayleigh fission from the ion evaporation mechanism.

The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

The composition of outer drop layers has been associated with distinct chemical reactivity. We use atomistic modeling to examine how the composition of the surface excess charge layer (SECL) is related to the ejection mechanisms of ions. Even though the drop disintegration is inherently a non-equilibrium process we find that the equilibrium ion distribution in SECL predicts the ions that are ejected. The escape of the ions in aqueous drops takes place from conical protrusions that are global drop deformations and their appearance is independent of the location of a single ion. Our results are consistent with the equilibrium partition model, which associates the mass spectrum with the distribution of analytes in the drop’s double electric layer. We present evidence that atomistic simulations of minute nano-drops cannot distinguish Rayleigh fission from the ion evaporation mechanism.

The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

The composition of outer drop layers has been associated with distinct chemical reactivity. We use atomistic modeling to examine how the composition of the surface excess charge layer (SECL) is related to the ejection mechanisms of ions. Even though the drop disintegration is inherently a non-equilibrium process we find that the equilibrium ion distribution in SECL predicts the ions that are ejected. The escape of the ions in aqueous drops takes place from conical protrusions that are global drop deformations and their appearance is independent of the location of a single ion. Our results agree with the equilibrium partition model, which associates the mass spectrum with the distribution of analytes in the drop’s double electric layer. We present evidence that atomistic simulations of minute nano-drops cannot distinguish Rayleigh fission from the ion evaporation mechanism.

An Attitude Prediction Method for Autonomous Recovery Operation of Unmanned Surface Vehicle

The development of launch and recovery technology is key for the application to the unmanned surface vehicle (USV). Also, a launch and recovery system (L&RS) based on a pneumatic ejection mechanism has been developed in our previous study. To improve the launch accuracy and reduce the influence of the sea waves, we propose a stacking model of one-dimensional convolutional neural network and long short-term memory neural network predicting the attitude of the USV. The data from experiments by “Jinghai VII” USV developed by Shanghai University, China, under levels 1–4 sea conditions are used to train and test the network. The results show that the stabilized platform with the proposed prediction method can keep the launching angle of the launching mechanism constant by regulating the pitching joint and rotation joint under the random influence from the wave. Finally, the efficiency and effectiveness of the L&RS are demonstrated by the successful application in actual environments.

Investigation of aerodynamics of separator delivery from cavity

The ejection test technology is studied in a sub-transonic supersonic wind tunnel using a single cylinder to provide ejection velocity. The angular velocity adjusting device of ejection mechanism is designed, which can adjust the ejection velocity and angular velocity of the model independently. When the ejection cylinder moves downward, the angular velocity adjusting mechanism works at the same time, so that the model has the preset ejection velocity and angular velocity at the moment of leaving the ejection frame. The ejection velocity error is less than 5%, the angular velocity error is less than 10%, and the repetition rate is more than 95%. The new technology has been verified by wind tunnel tests under complex aerodynamic conditions of sub-transonic supersonic and multi-body interference. All parameters have reached or surpassed the existing technical specifications. It has served for model tests many times and met the needs of wind tunnel test research on ejection of embedded weapons in aircraft.