Free vibration and critical speed of moderately thick rotating laminated composite conical shell using generalized differential quadrature method

The generalized differential quadrature method （GDQM） is employed to con- sider the free vibration and critical speed of moderately thick rotating laminated compos- ite conical shells with different boundary conditions developed from the first-order shear deformation theory （FSDT）. The equations of motion are obtained applying Hamilton＇s concept, which contain the influence of the centrifugal force, the Coriolis acceleration, and the preliminary hoop stress. In addition, the axial load is applied to the conical shell as a ratio of the global critical buckling load. The governing partial differential equations are given in the expressions of five components of displacement related to the points ly- ing on the reference surface of the shell. Afterward, the governing differential equations are converted into a group of algebraic equations by using the GDQM. The outcomes are achieved considering the effects of stacking sequences, thickness of the shell, rotating velocities, half-vertex cone angle, and boundary conditions. Furthermore, the outcomes indicate that the rate of the convergence of frequencies is swift, and the numerical tech- nique is superior stable. Three comparisons between the selected outcomes and those of other research are accomplished, and excellent agreement is achieved.

Analysis of Speeds of Cylinders of Saw Gins and Linters and Determination of Critical Frequencies for them

With an increase in the density of the seed roll in the roll box of the saw gin, the quality indicators of the fiber and seed are poor, energy consumption increases, machine breakdowns increase, and when the density decreases, the performance of the saw gin increases. Therefore, the density control of the seed roll is one of the important problems in the ginning process. The paper proposes a change in the rotation speed of the saw cylinder with a decrease in the diameter of its numerical linear speed and machine productivity. The article describes the problem of regulating the density of a seed roll in a saw gin of the DP series, provides an overview of work on regulating the operation of the machine, determines the dependence of the productivity of gins and linters on the state of the saw system in these machines, as well as changes in the linear speed of the saw by changing its diameter. Also, the critical speed of the gin and linter saw cylinder was determined to prevent resonance. In this case, the Simulation package of the SolidWorks computer program was used. The results of the study made it possible to adjust the speed of the cylinders when changing the diameter of the saws, which improved the productivity of the machine while maintaining the quality of the fiber and seed.

EFFECT OF THE GUIDES ON THE LOWEST CRITICAL ROTATIONAL FREQUENCIES OF CIRCULAR SAW

The effects of the location,number and stiffness of guide pads on the lowest critical rotational frequencies of the rotating circular saw damped at the inside and free at the perimeter are discussed by the non linear theory and the perturbation theory of structural vibration analysis The influence of the centrifugal force and the cutting temperature are considered in the course of the analysis The results of the analysis and the calculation show that the introduction of one guide does not stably raise critical rotational frequencies of the circular saw The two guides can raise lowest critical rotational frequency of the circular saw when the angle between the two guides fixed on the direction of the circumference satisfies the certain conditions

Stable stripe and vortex solitons in two-dimensional spin-orbit coupled Bose-Einstein condensates

We present a flexible manipulation and control of solitons via Bose-Einstein condensates.In the presence of Rashba spin-orbit coupling and repulsive interactions within a harmonic potential,our investigation reveals the numerical local solutions within the system.By manipulating the strength of repulsive interactions and adjusting spin-orbit coupling while maintaining a zero-frequency rotation,diverse soliton structures emerge within the system.These include plane-wave solitons,two distinct types of stripe solitons,and odd petal solitons with both single and double layers.The stability of these solitons is intricately dependent on the varying strength of spin-orbit coupling.Specifically,stripe solitons can maintain a stable existence within regions characterized by enhanced spin-orbit coupling while petal solitons are unable to sustain a stable existence under similar conditions.When rotational frequency is introduced to the system,solitons undergo a transition from stripe solitons to a vortex array characterized by a sustained rotation.The rotational directions of clockwise and counterclockwise are non-equivalent owing to spin-orbit coupling.As a result,the properties of vortex solitons exhibit significant variation and are capable of maintaining a stable existence in the presence of repulsive interactions.