On the use of outgoing longwave radiation data in incorporating divergent part of the wind in analysis

In the present study, kinematic divergence computed using ECMWF grid point data at 850 hPa is enhanced by using the relationship between OLR and divergence. This new enhanced divergence is used to compute the velocity potential and then, the divergence part of the wind is obtained from velocity potetial. To obtain the rotational part of wind, we computed the vorticity from wind data, and subsequently stream function and obtained and the rotational part of the wind from the stream function. The total wind is the combination of divergent part obtained from modified velocity potential (using OLR data) and rotational part from unmodified stream function. This total wind field is used as initial guess for univariate objective analysis by optimum interpolation scheme so that Initial Guess field contained the more realistic divergent part of the wind. Consequently, the analysed field also will contain the divergent part of the wind.

A frame-independent comparison metric for discrete motion sequences

To evaluate the kinematic performance of designed mechanisms, a statistical-variance-based metric is proposed in this article to measure the “distance” between two discrete motion sequences: the reference motion and the given task motion. It seeks to establish a metric that is independent of the choice of the fixed frame or moving frame. Quaternions are adopted to represent the rotational part of a spatial pose, and the variance of the set of relative displacements is computed to reflect the difference between two sequences. With this variance-based metric formulation, we show that the comparison results of two spatial discrete motions are not affected by the choice of frames. Both theoretical demonstration and computational example are presented to support this conclusion. In addition, since the deviation error between the task motion and the synthesized motion measured with this metric is independent of the location of frames, those corresponding parameters could be excluded from the optimization algorithm formulated with our frame-independent metric in kinematic synthesis of mechanisms, and the complexity of the algorithm are hereby reduced. An application of a four-bar linkage synthesis problem is presented to illustrate the advantage of the proposed metric.

Study on Rotary Bending Forming Process of Torsional Damper Shell Pulley

To study the integral forming process of torsion damper shell pulley with characteristic structure is of great significance for producing and developing of the rotational part such as shell pulley. A processing way was proposed by combining plate bending forming and roller structure design, to integral forming torsion damper shell pulley. A model for two-step bending forming was establishedvia finite element method. Under the radial feeding of roller, the outer edge of plate was subjected to compress thickening and secondary thickened after bending, and effective stress and metal flow in the deformation zone were analyzed by using marking point. Combining with the structural characteristics of shell pulley, a design criterion "rotating thickening, gathering thickening" of roller was proposed. The metal flow in deformation zone was effectively controlled through the characteristic structure of roller, thereby the specific region to forming multi-wedge toothwas obtained. The quantitative analysis of the instantaneous part section in the forming process, combining with the design criteria of roller structure and material flow rate, radius and arc angle of roller were determined. With the objective forming parameters, the comparison between the simulation results and the experimental are basically coincided, the ribs were fully formed and the specific regions was thickened to minimum value, which verified the feasibility of sheet-bulk metal rotary bending forming theory and the design criterion of roller structure.

Fujita–Kato solution for compressible Navier–Stokes equations with axisymmetric initial data and zero Mach number limit

In this paper, we investigate the question of the existence of global strong solution for the compressible Navier–Stokes equations for small initial data such that the rotational part of the velocity [Formula: see text] belongs to [Formula: see text] (in dimension [Formula: see text]). We show then an equivalent of the so-called Fujita–Kato theorem to the case of the compressible Navier–Stokes equations when we consider axisymmetric initial data. The main difficulty is linked to the fact that in this case the velocity is not Lipschitz, as a consequence we have to study carefully the coupling between the rotational and irrotational part of the velocity. In a second part, we address the question of convergence to the incompressible model (for ill-prepared initial data) when the Mach number goes to zero.

Design and Analysis of a Novel Piezo-Actuated XYθz Micropositioning Mechanism with Large Travel and Kinematic Decoupling

A novel hybrid-type XYθz micropositioning mechanism driven by piezoelectric actuators is proposed in this paper. With the purpose of realizing a large motion range and 3-DoF independent motion within a compact size, the mechanism is designed using a symmetric translational part and a rotational part that are linked serially. The translational part is based on a double-amplification mechanism incorporating a guidance mechanism for decoupling; the rotational part uses a nonuniform beam with an amplification mechanism to translate the linear output displacement of piezoelectric actuators into a large rotational angle around the Z axis. To precisely predict the output displacements and implement dimensional design, electromechanical models of the translational mechanism and rotational mechanism are established. According to the theoretical model, dimensional optimization is carried out to achieve large motion ranges within a compact size. A prototype of the proposed mechanism is fabricated according to the optimized results, and the performance of the mechanism is validated by experiment. The experimental results show that translational travel in X and Y directions of 204.2 μm and 212.8 μm, respectively, and travel of 8.7 mrad in the θz direction can be realized in a small size of 106 mm × 106 mm × 23 mm. And, the output coupling was evaluated to be below 3%, indicating an excellent decoupling performance.

Study of the high rotational bands of heavy nuclei (A=190) by An approach keeping the number of particles: دراسة منطقة الدوران العالية للانوية الثقيلة(A » 190) باستعمال الحفاظ على عدد الجسيمات

Current study propuse to treat on first all what is mentioned the these statment which role essentially in two steps .First, we start with a presentation of the formalism of the approach HTDA (Higher Tamm Dancoff approximation).This approximation is based on the excitations particle-hole permits the conservation of a number of particles in a middle field. A special attention will be drifted on the HTDA code with triaxial symmetry that we will extend in a way that allows us to include in the Hamiltonian a rotational part to process the collective modes of rotation in the deformed nuclei. Secondly, the Cranking version of this formalism (Cr.HTDA) Will allow us to calculate the moments of inertia of the super-distorted bands of nuclei in the mass region A ~190.These will be compared to the experimental data and with those of the Cranking version of the approach Hartree- Fock- Bogoliubov. This work, will offer an interesting perspectives, calling for certain ameliorations or extensions of the HTDA code.

Definitions of vortex vector and vortex

Although the vortex is ubiquitous in nature, its definition is somewhat ambiguous in the field of fluid dynamics. In this absence of a rigorous mathematical definition, considerable confusion appears to exist in visualizing and understanding the coherent vortical structures in turbulence. Cited in the previous studies, a vortex cannot be fully described by vorticity, and vorticity should be further decomposed into a rotational and a non-rotational part to represent the rotation and the shear, respectively. In this paper, we introduce several new concepts, including local fluid rotation at a point and the direction of the local fluid rotation axis. The direction and the strength of local fluid rotation are examined by investigating the kinematics of the fluid element in two- and three-dimensional flows. A new vector quantity, which is called the vortex vector in this paper, is defined to describe the local fluid rotation and it is the rotational part of the vorticity. This can be understood as that the direction of the vortex vector is equivalent to the direction of the local fluid rotation axis, and the magnitude of vortex vector is the strength of the location fluid rotation. With these new revelations, a vortex is defined as a connected region where the vortex vector is not zero. In addition, through direct numerical simulation (DNS) and large eddy simulation (LES) examples, it is demonstrated that the newly defined vortex vector can fully describe the complex vertical structures of turbulence.

Software Development for Setup Planning of Rotational Part

An innovative approach was developed to solve the problem of setup planning, which is the most critical problem in process planning for discrete metal parts. Setup planning is the act of preparing detailed work instructions for setting up a part. The major objective of this research is to improve the performance of CAPP systems by developing a systematic approach to generate practical setup plans based on tolerance analysis. A comprehensive literature review on tolerance control in CAPP was conducted. It was found that tolerance chart analysis, a traditional tolerance control technique, is reactive in nature and can be greatly improved by solving the problem of setup planning. In order to develop a theoretically sound foundation for tolerance analysis-based setup planning, the problem of tolerance stack up in NC machining was analyzed in terms of manufacturing error analysis. Guidelines for setup planning were then developed based on the analysis. To systematically solve the setup planning problem, a graph theoretical setup planning algorithm for rotational parts was then developed for automated and integrated setup planning and fixture design. Its efficiency and effectiveness evaluated. The result is promising. The algorithms were then computerized. A setup planning program was developed under the Microsoft Windows environment using C.