Regularity Of Motion Research Articles

Regularities of motion of a particle in the spiral–screwed device

The article describes the functional relationship between the geometric parameters of the spiral screw and the kinematic motion characteristics of the material being moved and its individual particles. The authors considered the movement of a particle in the cylindrical system of coordinates. Differential equations have been obtained, which describe the motion trajectory of a material particle along the inner surface of the casing of a spiral–helical device.

CFD ANALYSIS OF THE HEAT TRANSFER OF SUPERCRITICAL WATER UNDER CONDITIONS OF MIXED CONVECTION

The results of computer modeling of heat exchange supercritical water, associated with the influence of gravity, are presented. CFD prediction data on heat transfer coefficients and temperatures of the inside surface of the tube wall, obtained with and without buoyancy, are presented. An interpretation of these predictions, which is associated with the turbulent transfer extinction near the tube wall in the case of buoyancy forces, is given. The analysis of the influence of buoyancy forces on the configuration of the radial temperature profiles of supercritical water was performed. The data on the regularities of motion of the pseudo-phase transition front in the presence and absence of accounting for buoyancy forces have been obtained.

Effect of Fluid Viscosity on the Faraday Surface Waves

The comprehensive experimental analysis of the fluid viscosity effect on the standing gravity waves excited at parametric resonance is carried out. The viscous effects on the frequency range of excitement of the second wave mode, its resonance dependences, and the processes of damping and approaching the steady-state regime are quantitatively estimated by varying the viscosity over a wide range. It is found that the waves are regularized without breaking when the kinematic viscosity of the workingmedium becomes higher than a threshold value. A mechanism of viscous regularization of wave motion is suggested. In accordance with this mechanism, the effects observed experimentally relate to the presence of the shortwave cutoff domain in which viscous dissipation becomes the dominant factor and the shortwave perturbations responsible for breaking the standing wave are suppressed.

Simulation of oscillation of magnetic particles in 3D microchannel flow subjected to alternating gradient magnetic field

Abstract Magnetic particles (MPs) have good response to external magnetic field. To investigate the motion regularity of MPs in a mcirochannel flow governed by alternating gradient magnetic field, a 3D numerical simulation method is established based on the lattice Boltzmann method (LBM) and the immersed boundary method (IBM). The motions of both a single MP and a short chain of MPs are investigated and each is found to be a superposition of transverse oscillation and longitudinal translation. By performing a simple filtering processing for the original trajectory of MP, it is revealed that the oscillation of MPs affected by alternating gradient magnetic field can be characterized as the simple harmonic vibration. The oscillation frequency of MPs is basically in accordance with the alternating frequency of the gradient magnetic field in the range from 400 to 800 Hz. The larger magnetic field gradient results in the larger amplitude of oscillation. The wavelength of the trajectory is increased due to the increasing inlet velocity of carrier fluid. For the MP chain, both the period and amplitude of oscillation will decrease with the increase of alternating frequency of magnetic field. The turbulence intensity distribution indicates that the turbulence of microchannel flow can be enhanced by the oscillation of MPs thus enhance the mass or heat transfer in the carrier fluid.

Effect of respiratory guidance on internal/external respiratory motion correlation for synchrotron-based pulsed heavy-ion radiotherapy

Having implemented an audio-visual biofeedback (BFB) method for respiratory-gated radiotherapy of synchrotron-based pulsed heavy-ion beam delivery with tracking of external abdominal wall motion, this study evaluated the feasibility of the respiratory guidance method on thoracic and abdominal cancer patients, and the internal/external respiratory motion consistency under respiratory guidance maneuvers due to its interactive intervention in free breathing (FB). A total of 42 breathing traces from seven lung and breast cancer patients and corresponding fluoroscopy movies under FB, standard breath hold (stBH) and representative breath hold (reBH) guidance maneuvers were analyzed. Diaphragm motions were measured manually on a frame-by-frame basis. Mean absolute deviation (MAD) values of the measured external motion curves were calculated for the FB and guidance maneuvers, and the internal/external motion consistencies were compared with a linear fit. Compared with FB, the MAD values were reduced significantly with respiratory guidance maneuvers. The mean internal/external correlations of the first treatment fraction were determined to be 0.96 ± 0.03, 0.97 ± 0.02, and 0.97 ± 0.03 for the FB, stBH and reBH guidance maneuvers, respectively, and were 0.95 ± 0.03, 0.97 ± 0.03, and 0.98 ± 0.02 for the second treatment fraction. No phase shift between the two breathing signals was observed, and good reproducibility of consistency of breathing guidance between the two fractions was achieved. These results demonstrated that treatment precision could be improved for cancer patients with audio-visual BFB, and a strong correlation between diaphragm motion and abdominal wall motion was obtained. The use of audio-visual BFB improved the regularity of both internal and external motions, allowing confident use of the audio-visual BFB method by tracking of the external abdominal wall motion to synchrotron-based heavy-ion radiotherapy.

Analysis of the influence of radiation polarization type on the absorptive capacity and propulsive motion of microparticles in the light field of СО2 laser

The influence of the linear and circular polarization of laser radiation on the absorption coefficient of single spherical AISI-304 steel particles was theoretically analyzed. It is shown that the absorbed power of the laser beam depends on the particle sizes and on the location of particles in the light field. The influence of the laser-induced evaporation of the material on the regularities of the reactive motion of particles at a power density in the beam exceeding some threshold value is established. The direction of the action of the reactive force is directly related to the nonuniform distribution of the absorbed laser-emitted power and with the recoil pressure of the vapors moving away from the curvilinear surface of particle. A description to the mechanism of deflection of the particle’s reactive force vector due to the vapor recoil pressure in the light field of a Gaussian beam from the direction of the beam action is given.

GIFTed Demons: deformable image registration with local structure-preserving regularization using supervoxels for liver applications.

.Deformable image registration, a key component of motion correction in medical imaging, needs to be efficient and provides plausible spatial transformations that reliably approximate biological aspects of complex human organ motion. Standard approaches, such as Demons registration, mostly use Gaussian regularization for organ motion, which, though computationally efficient, rule out their application to intrinsically more complex organ motions, such as sliding interfaces. We propose regularization of motion based on supervoxels, which provides an integrated discontinuity preserving prior for motions, such as sliding. More precisely, we replace Gaussian smoothing by fast, structure-preserving, guided filtering to provide efficient, locally adaptive regularization of the estimated displacement field. We illustrate the approach by applying it to estimate sliding motions at lung and liver interfaces on challenging four-dimensional computed tomography (CT) and dynamic contrast-enhanced magnetic resonance imaging datasets. The results show that guided filter-based regularization improves the accuracy of lung and liver motion correction as compared to Gaussian smoothing. Furthermore, our framework achieves state-of-the-art results on a publicly available CT liver dataset.

Double-curved disc ultrasonic-assisted lapping of precision-machined crowned rollers

To improve the convexity uniformity, processing efficiency, and surface quality of precision-machined crowned rollers, this paper proposes a double-curved disc ultrasonic-assisted lapping (DUAL) method. Firstly, a DUAL machine is designed according to the technical requirements of crowned roller lapping, and the working principle is presented. Then, the ultrasonic-coupled processing mechanism for crowned roller surfaces is analyzed, and the abrasive particle motion and material removal regularities under cavitation are acquired. Subsequently, an ultrasonic amplitude transformer for DUAL is developed, and the DUAL experimental platform for precision-machined crowned rollers is established. Finally, comparative processing experiments using non-ultrasonic lapping and through-feed super-finishing are performed. The experimental results indicate that the proposed DUAL method can improve processing efficiency and surface roughness, and also the batch uniformity of the convex metric.

The effects of regularity of simulated ship motions on the behaviour and physiology of sheep

Floor movement influences sheep responses to transport, but the importance of movement regularity and interactions between sheep are unknown. To test this, sheep were restrained in pairs in a crate mounted on a moveable, programmable platform for 60 min periods, changing treatments over 12 consecutive days. In an initial experiment a repeated speed of movement and change in angle (regular movement) was compared to variable angles and speeds (irregular movement) of roll, pitch or combined movements, for sheep behaviour, heart rate and feed and water intake responses. Feed intake was increased by irregular roll+pitch motion (P = 0.04). During irregular sequences sheep affiliated more, with their heads one above the other (P = 0.001) and supported themselves against the crate (P < 0.001) or kneeling (P = 0.03). Irregular sequences and combined roll and pitch synergistically increased stepping behaviour, indicating loss of balance, and heart rate, possibly indicating stress (P < 0.001). Heat rate data demonstrated that the RMSSD band was reduced during irregular movement (P = 0.04), and LF/HF ratio increased during irregular sequences of roll+pitch (P = 0.007), suggesting less parasympathetic nervous system activity. In a second experiment, we investigated the effects of these floor motion patterns with and without a barrier to separate the sheep. With no barrier or irregular motion, sheep stepped more to avoid loss of balance (P < 0.001) and were again more affiliative. During irregular motion they supported themselves more against the crate (P < 0.001). With no barrier there was more agonistic behaviour (body pushing (P = 0.02), butting (P = 0.02) and evading the other sheep (P = 0.001) and less rumination (P = 0.02), which together with a reduction in RMSSD and NN50 suggested that sheep welfare was reduced by the close proximity of the other sheep. The ratio of low to high frequency beats was highest (P = 0.005) and the RMSSD and NN50 were lowest (P < 0.001) during irregular motion and no barrier. Evidence is provided that sheep were both more stressed in this combination of treatments and also exercising more, through stepping behaviour. Thus irregular sequences and combined roll and pitch caused stress and increased activity to correct loss of balance, as well as increased affiliative behaviour. Separating sheep during irregular motion reduced body instability and stress, suggesting that close stocking is detrimental to their welfare.

Multi-Step Control of Chaos in the Application of Earth-Moon Orbit Transfer

A multi-step control of chaos method is proposed in this paper to reduce the flight time in the chaotic region of Earth-Moon low-energy orbit transfer. According to the motion regularity and the fact that the chaos orbit is highly sensitive to the initial conditions in the circular restricted three-body system, the optimal perturbation of chaos control at each step is calculated by the adaptive particle swarm optimization algorithm, and then the low-energy earth-moon orbit transfer trajectory is obtained. This proposed method can efficiently construct the Earth-Moon low-energy orbit transfer trajectory without the relying on the periodic orbits and the requirement of random search, and the corresponding flight time in chaotic motion can be significantly reduced. Finally, numerical simulations are provided to demonstrate the correctness and efficiency of this proposed method.

An adaptive motion regularization technique to support sliding motion in deformable image registration.

Isotropic smoothing has been conventionally used to regularize deformation vector fields (DVFs) in deformable image registration (DIR). However, the isotropic smoothing method enforces global smoothness and therefore cannot accurately model the complex tissue deformation, such as sliding motion at organ boundaries. To accurately model and estimate sliding tissue motion, an adaptive direction-dependent DVF regularization technique was developed in this study. A DVF is computed and updated iteratively by minimizing the intensity differences between the images. In each iteration, the DVF was smoothed using an adaptive direction-dependent filter which enforces different motion propagation mechanisms along the primary normal and tangential directions of soft tissue local structures. A Gaussian isotropic filter was used along the normal direction while a bilateral filter was used along the tangential direction. To support large sliding motion, an automatic method was developed to delineate sliding surfaces, such as the chest wall and abdominal wall, where large organ sliding motion occurs. Parameters of the DVF regularization were adjusted adaptively based on a distance map to the sliding surfaces. The proposed method was tested on 14 4D-CT datasets at End-Inhalation (EI) and End-Exhalation (EE) phases of a respiratory cycle (10 public lung datasets, 3 upper abdomen datasets and 1 digital phantom dataset). TRE results of the 10 lung datasets were compared to results from six other existing DIR methods. For the three upper abdomen patient datasets, DIR accuracy was evaluated using manually defined landmarks across the lung and the abdomen. For the digital phantom dataset, DIR accuracy was evaluated using the ground truth displacement of a total 40,000 points that were evenly distributed across the phantom. The results showed that the sliding motion was preserved near the surface of chest wall and abdominal wall. The average target registration error (TRE) was reduced by 35.1% using the proposed method in comparison with five other methods on the 10 lung datasets. The sum of squared difference (SSD) after registration using the proposed method was 4.4% and 11.4% smaller than the SSDs obtained using isotropic smoothing and bilateral smoothing respectively. On the digital phantom, the average TRE was reduced by 59.6% near the surface of liver and by 53.7% near the surface of spleen using the proposed method. Contour propagation and Jacobian determinant analysis of DVF suggested an overall improved accuracy using the proposed method. An adaptive direction-dependent DVF regularization method has been developed to model the sliding tissue motion of the thoracic and abdominal organs. The overall motion estimation accuracy has been improved especially near the chest wall and abdominal wall where large organ sliding motion occurs.

Relationship between the Power of the Two-Bit Cutting Body Rotation Drive of the Roadheader and Hardness of Broken Rock

The motion patterns of the cutting body of a roadheader with two kinematically connected reversible radial bits equipped with a disk tool on trihedron prisms are presented. The regularity of the disks motion under the action of forces applied to them is considered with allowance for the moments of inertia. The scheme of forming the depth of intrusion by the biconical disc tool of radial bits into the face rock strata is substantiated. The calculated dependences of the total torques ΣMk on the cutting body of the roadheader are obtained from the angle ρ of the bitsrotation, taking into account the contact strength Pk of the rock strata to be broken. The calculation is made of the power of the rotation drive of the two-bit cutting body with a disk tool on trihedral prisms in breaking the rock strata in the range of strength characteristics for the mines of Kuzbass.

A variational reconstruction method for undersampled dynamic x-ray tomography based on physical motion models

In this paper we study the reconstruction of moving object densities from undersampled dynamic x-ray tomography in two dimensions. A particular motivation of this study is to use realistic measurement protocols for practical applications, i.e. we do not assume to have a full Radon transform in each time step, but only projections in few angular directions. This restriction enforces a space-time reconstruction, which we perform by incorporating physical motion models and regularization of motion vectors in a variational framework. The methodology of optical flow, which is one of the most common methods to estimate motion between two images, is utilized to formulate a joint variational model for reconstruction and motion estimation.We provide a basic mathematical analysis of the forward model and the variational model for the image reconstruction. Moreover, we discuss the efficient numerical minimization based on alternating minimizations between images and motion vectors. A variety of results are presented for simulated and real measurement data with different sampling strategy. A key observation is that random sampling combined with our model allows reconstructions of similar amount of measurements and quality as a single static reconstruction.

Objective Video Quality Assessment Based on Perceptually Weighted Mean Squared Error

Object quality assessment for compressed video is critical to various video compression systems that are essential in the video delivery and storage. Although mean squared error (MSE) is computationally simple, it may not be accurate to reflect the perceptual quality of compressed videos, which are also affected dramatically by the characteristics of the human visual system (HVS), such as contrast sensitivity, visual attention, and masking effect. In this paper, a video quality metric is proposed based on perceptually weighted MSE. A low-pass filter is designed to model the contrast sensitivity of the HVS with the consideration of visual attention. The imperceptible distortion is adaptively removed in the salient and nonsalient regions. To quantitatively measure the masking effect, the randomness of video content is proposed in both the spatial and temporal domains. Since the masking effect highly depends on the regularity of structure and motion in the spatial and temporal directions, the video signal is modeled as a linear dynamic system, and the prediction error of future frames from previous frames is used as randomness to measure the significance of masking. The relation is investigated between MSE and perceptual quality scores across various contents, and a masking modulation model is proposed to compensate the impact of the masking effect on the MSE. The performance of the proposed quality metric is validated on three video databases with various compression distortions. The experimental results demonstrate that the proposed algorithm outperforms other benchmark quality metrics.

Detecting Biological Motion for Human–Robot Interaction: A Link between Perception and Action

One of the fundamental skill supporting safe and comfortable interaction between humans is their capability to understand intuitively each other's actions and intentions. At the basis of this ability is a special-purpose visual processing that human brain has developed to comprehend human motion. Among the first building blocks enabling the bootstrapping of such visual processing is the ability to detect movements performed by biological agents in the scene, a skill mastered by human babies in the first days of their life. In this paper we present a computational model based on the assumption that such visual ability must be based on local low-level visual motion features which are independent of shape, such as the configuration of the body, and perspective. Moreover, we implement it on the humanoid robot iCub, embedding it into a software architecture that leverages the regularities of biological motion also to control robot attention and oculo-motor behaviors. In essence, we put forth a model in which the regularities of biological motion link perception and action enabling a robotic agent to follow a human-inspired sensory-motor behavior. We posit that this choice facilitates mutual understanding and goal prediction during collaboration, increasing the pleasantness and safety of the interaction.

Oscillatory–ballistic motion regularities of a gravitational pendulum

We simulate the motion of a gravitational pendulum that has initial angular amplitude larger than 90\(^{\circ }\) and smaller than 180\(^{\circ }\), and loses energy at each change from ballistic to oscillatory motion when the string is suddenly tensed (we name this event collision). Simulation is based on a velocity Verlet algorithm that is implemented in a numerical code. The numerical simulation of motion as function of time is checked against an analytical code that describes the trajectory. The string tension expression that respects the velocity Verlet algorithm requirements is identified and a criterion for collision occurrence is introduced. An interesting band-like structure of the number of collisions as function of the initial amplitude and damping modelling is obtained.

Macroscopic motion of sheath-connected blobs in magnetic fields with arbitrary topology

In this study, macroscopic motion of sheath-connected blobs in magnetic fields, having arbitrary topology of the field lines and unfrozen in plasma, is analyzed within the electrostatic limit. Two distinct cases of magnetic configurations, with small and large curvature of the field lines, are considered and the criterion to discern them is deduced. For magnetic configurations with small curvature of the field lines, it is demonstrated that asymmetry of plasma distribution at the blob ends can drive macroscopic motion of a filament due to formation of unequal sheath potentials and establishing the effective Boltzmann potential. For a specific case of magnetic fields with small curvature of the field lines and identical metrics at the sheaths, we show that macroscopic motion of a plasma filament is determined by an effective electrostatic potential, which remains constant in time. For magnetic configurations with large curvature of the field lines, it is shown that motion of sufficiently large blobs is governed by integral distribution of plasma and magnetic field parameters along the field lines leading to blob adjusting its shape and position to the lead of the magnetic field lines in the course of its motion, whereas propagation of small and medium sized blobs can be represented as mutually independent motion of filament transverse cross-sections across the magnetic field lines. The qualitative conclusions on regularities of filament motion are supplied with numerical simulations of blob dynamics in two cases of tokamak-like magnetic fields with sheared and non-sheared field lines.

Modelling and Simulation of Vessel Alongside Replenishment Motion Response Based on Sea Conditions Analysis

Offshore accurate replenishment technology is a vital basement of conducting ocean research and deep ocean exploitation for every advanced country. However, It’s necessary to compensate waving for ensuring the security and accuracy of offshore project due to the fact that wave makes vessel generate 6-DOF motions. This paper set offshore accurate supplying for vessels as the background, basing on Froude-Krylov assumption, to do research on 6-DOF motion responses of different sea conditions. This paper builds the vessel motion response formulas on the basis of the 3-dimensional potential theory and then resolve it by AQWA. The simulation results indicate the regularity of vessel motions, which can be considered as requirement indicators during designing AHC (Active Heaving Compensation) system.

Monocular, Boundary-Preserving Joint Recovery of Scene Flow and Depth

Variational joint recovery of scene flow and depth from a single image sequence, rather than from a stereo sequence as others required, was investigated in Mitiche et al. (2015) using an integral functional with a term of conformity of scene flow and depth to the image sequence spatiotemporal variations, and L2 regularization terms for smooth depth field and scene flow. The resulting scheme was analogous to the Horn and Schunck optical flow estimation method except that the unknowns were depth and scene flow rather than optical flow. Several examples were given to show the basic potency of the method: It was able to recover good depth and motion, except at their boundaries because L2 regularization is blind to discontinuities which it smooths indiscriminately. The method we study in this paper generalizes to L1 regularization the formulation of Mitiche et al. (2015) so that it computes boundary preserving estimates of both depth and scene flow. The image derivatives, which appear as data in the functional, are computed from the recorded image sequence also by a variational method which uses L1 regularization to preserve their discontinuities. Although L1 regularization yields nonlinear Euler-Lagrange equations for the minimization of the objective functional, these can be solved efficiently. The advantages of the generalization, namely sharper computed depth and three-dimensional motion, are put in evidence in experimentation with real and synthetic images which shows the results of L1 versus L2 regularization of depth and motion, as well as the results using L1 rather than L2 regularization of image derivatives.

Mathematical model of oriented planting of bulbs with bulb stem pointing downwards

Theoretical studies are carried out on the substantiation of design and technological parameters of vibration and pneumatic planting unit of a bulb-planting machine, and of a disc coverer with soil deflectors. The subject of research is the process of oriented planting and embedding of seed onion bulbs into soil. The article considers the process of bulbs orienting during planting and their orientation maintaining during interaction with the soil, taking into account the regularities of bulbs motion by means of vibrating chute and pneumatic drum, as well as the work of coverers during covering of bulbs with soil. The research is done on the basis of laws of classical mechanics and Lagrange's equations of the second kind. Theoretical studies of the working process of vibration and pneumatic planting unit of a bulb-planting machine are carried out. As a result, analytical dependences are obtained for determination of its design and operational parameters: the groove radius, the distance between chute and groove bottom, the diameter of suction opening, the rotation speed of pneumatic drum, the height of planting unit installation above the soil level. The studies allowed to determine: the condition of oriented embedding of bulbs into furrow with bulb stem pointing downwards; the analytical dependences for determining the trajectory of soil particles motion on the working surface of deflector of a disc coverer; the equation of soil particles motion after detachment from deflector’s surface, during covering with soil of bulbs oriented in furrow with bulb stem pointing downwards; the equations of relative, transfer and absolute velocities of soil particles. The expressions are obtained that allow to determine the technological parameters of disc coverer with soil deflectors: the forward velocity of disc coverer, the angle of attack, the center distance between discs.