Arbitrary Inclination Angle Research Articles

On the Evolution of Angles between the Magnetic Moment and the Axis of Rotation in Radio Pulsars

Three methods were used to calculate the angles β between the magnetic moment and the axis of rotation of central neutron stars for 307 known radio pulsars. There is no explicit statistical dependence of the calculated angles β on the kinematic age of pulsars. It follows from this that either the indicated angle does not change noticeably with the age of the pulsar, or pulsars are born with an arbitrary inclination angle.

Analytical Study of the Stagnation Point Properties and Impact Forces for Non-Continuum Flow Out of Planar Exit Impinge on Inclined Flat Plate Surface

This paper investigated the stagnation point properties and the impact forces acting on the flat plate exposed to rarefied flow with arbitrary inclination angle issuing from planner nozzle. The gaskinetic method was used to investigate this problem. The analytical solutions for the drag and the shear forces were derived. The parameters that effect on drag, shear forces and their coefficients and the stagnation point properties were studied, focusing on the effect of plate inclination angle. The results were as follows: the drag and shear forces increased with the increasing the plate inclination angle, area of the plate, the temperature of issuing gas, and the temperature of the plate. The drag and the shear forces decreased with increasing the distance between the nozzle and the center of the plate and the exit speed ratio. The stagnation pressure and the heat flux coefficients increased with increasing the plate inclination angle, the exit speed ratio, and by decreasing the distance between the nozzle exit and the center of plate and the gas temperature. The direct simulation Monte Carlo method was used to validate the analytical results of this study. The comparisons between the numerical results that obtained from the direct simulation Monte Carlo method and the analytical solutions were in good agreement.

Graphical Direct Writing of Macroscale Domain Structures with Nanoscale Spatial Resolution in Nonpolar-Cut Lithium Niobate on Insulators

We report on a graphical domain engineering technique with the capability to fabricate macroscale domain structures with nanoscale spatial resolution in nonpolar-cut lithium-niobate thin film on insulators through the biased probe tip of scanning atomic force microscopy. It is found that the domain writing process is asymmetric with respect to the spontaneous polarization ${\mathrm{P}}_{s}$ even though the tip-induced poling field is mirror symmetric. Various domain structures, with a dimension larger than millimeters while consisting of nanoscale domain elements and with arbitrary domain-wall inclination angle with respect to ${\mathrm{P}}_{s}$ , are designed graphically and then written directly into nonpolar-cut lithium-niobate crystals. As a proof-of-principle demonstration, periodically poled $x$-cut lithium-niobate thin film on insulators with a period of 600 nm, a depth of 460 nm, and a length of approximately $1$ mm is fabricated. This technique could be useful for device applications in integrated optics and optoelectronics and domain-wall nanoelectronics based on lithium niobate on insulators.

A geometrical optimization and comparison study on the charging and discharging performance of shell-and-tube thermal energy storage systems

Shell-and-tube latent heat thermal energy storage (ST-LHTES) systems have been extensively studied due to their high thermal/cold storage capacity during the charging/discharging process and their wide range of applications. The thermal performance of these systems is heavily dependent on the shape and geometry of the shell part. This research aims to investigate the transient heat transfer of phase change material (PCM) in the vertical ST-LHTES systems during charging (melting) and discharging (solidification) and the impact of geometric design on the heat transfer characteristics and consequently the thermal performance of the system in both processes. For this purpose, phase change heat transfer in a conventional cylindrical shell is compared with conical configurations with arbitrary inclination angles. The different heat transfer characteristics, e.g., the rate of phase change fraction and the energy stored/released, are determined and compared for all systems to evaluate their thermal performance and find the optimal design. The phase change process is also numerically visualized to track the phase change interface during both charging and discharging processes. A dynamic adaptive mesh refinement technique is implemented to capture gradients and simulate phase change front accurately. Depending upon the inclination angle, a favorable result can be achieved for the charging process in conical shape compared with a cylindrical geometry, while inverse results are obtained for the discharging process. In other words, increasing the lateral slope of the shell from a vertical to tilted state enhances the melting process resulting in a faster energy storage rate during the charging process, whereas decreasing this slope leads to better thermal performance for discharging process. The optimum designs can improve the system performance by 52% and 56% for the charging and discharging processes, respectively. A comprehensive experimental setup is developed for the cylindrical case to visualize and compare the charging and discharging process experimentally as well. Results obtained from numerical simulations exhibit similar patterns to experimental visualizations.

Relativistic oblique shocks with ordered or random magnetic fields: tangential field governs

ABSTRACT Relativistic magnetohydrodynamic shocks are efficient particle accelerators, often invoked in the models of gamma-ray bursts (GRBs) and shock-powered fast radio bursts (FRBs). Most theoretical studies assume a perpendicular shock with an ordered magnetic field perpendicular to the shock normal. However, the degree of magnetization σ and the magnetic field geometry in shock-powered GRB/FRB scenarios are still poorly constrained by observations. Analogous to the magnetization σ associated with the total field strength, we define a tangential magnetization σ⊥ associated with the tangential field component. We explore the jump conditions of magnetized relativistic shocks, either with an ordered field of arbitrary inclination angle or with a random field of arbitrary anisotropy. In either case, we find that the jump conditions of relativistic shocks are governed by the tangential magnetization σ⊥ instead of the total magnetization σ, insensitive to the inclination angles or the anisotropy of the pre-shock magnetic field. The approximated analytical solution developed in this work could serve as a quick check for numerical simulations and apply to theoretical studies of GRBs/FRBs with a more general field geometry.

Method of the Generalized Approach to the Synthesis of Cam Mechanisms

The technique of applying the equation of the geometric connection of links in the higher kinematic pair of a cam mechanism for the complete synthesis of a mechanism with a flat translationally moving pusher with an arbitrary angle of inclination of the plate is considered. A distinctive feature of the technique is that the equation of the cam profile envelope is derived from the equation of the geometric relationship of the cam and the pusher in the Cartesian coordinate system. All transformations, the solution of the original coupling equation and the envelope equation are carried out by the matrix method in the same coordinate system without switching to other coordinate systems and to graphical methods of their interpretation. As a result of the performed studies, calculated relations for determining the coordinates of the cam profile points at an arbitrary angle of inclination of the pusher plate were obtained. The formula for determining the curvature radius of the cam at an arbitrary inclination angle of the plate is derived. The procedure for determining the radius of the main cam circumference is proposed, taking into account the identified features of the cam profile plotting. Based on the developed methodology, software in the MathCad package has been created. The correctness of the methodology and software was tested on a numerical test case. In the course of computer modeling, the reason for the need to limit the value of the inclination angle of the plate is established, due to the phenomenon of cam profile self-intersection, which does not depend on the pressure angle and is not tracked by the condition of the convexity of its profile. The test results allow us to assert that the generalized method of flat cam mechanisms synthesis is correct and effective, therefore it has prospects of application, for example, for a cam mechanism with a flat rotating pusher.

On large deformation and stability of microcantilevers under follower load

In the present study, a novel geometrically exact nonlinear beam model based on the nonlinear displacement field, centerline-inextensibility condition, Euler-Bernoulli beam hypothesis, and modified couple stress theory is established to investigate the extremely large deformations and stability characteristics of size-dependent microcantilevers subjected to a tip-concentrated non-conservative (follower type) load with arbitrary inclination angle. The newly developed mathematical formulation explains the size effect phenomenon in the microcantilevers with only one material length scale parameter. The nonlinear shooting method for two-point boundary value problems is utilized to assess the deformed configuration of microsystem based on the quasistatic form of nonlinear mathematical model. Afterwards, the linearized dynamical mathematical model around the nonlinear deformed configurations of microsystem is numerically solved using the Galerkin technique to examine the stability of obtained responses. A comprehensive investigation is then conducted to highlight the role of size-dependency in the critical follower force at which the microsystem undergoes a flutter instability, as well as the nonlinear large deformation of microsystem in the pre-flutter region.

Analysis and Control of an In-Pipe Wheeled Robot With Spiral Moving Capability

Abstract This article presents analysis and control of a wheeled robot that can move spirally inside the pipeline. The wheeled robot considered is composed of two mechanical bodies, a pair of differential-drive wheels, a lifting motor, and a steering wheel. The mechatronic design allows the robot to easily press against the inner wall and spiral along pipelines of arbitrary inclination angles. Kinematic analysis shows how the lead angle of the differential-drive wheels and the steering angle should be coordinated so as to achieve stable spiraling. The steady-state force analysis further gives an analytic expression for the threshold torque needed for supporting the robot at different inclination angles. To ensure successful operation of the robot, four control systems that respectively regulate the spiraling speed, the lifting torque, the steering angle, and the lead angle are devised. Particularly for the lead angle control, it is theoretically proved that the feedback measurement can be obtained by performing algebraic operation on signals from a multi-axis gyro. A prototype robot is constructed and is controlled based on the analysis results. Experiments are conducted to verify the robot’s performance on moving spirally in pipelines of different inclination angles.

Static and dynamic stiffness in the modeling of inclined suspended cables

Inclined suspended cables (ISCs) have several applications in the transmission lines of power network systems. This study attempts to simplify the modeling of ISCs by addressing their static and dynamic stiffness. The dynamic problem of a uniform damping ISC under a harmonic excitation is studied under the assumptions that the suspended cable is deflected in a parabolic profile during static equilibrium and all the displacements in the dynamic in-plane motion are small. A closed expression for the frequency response function (FRF) is derived, based on which the static stiffness of the ISC is established; this aids in modifying the Ernst's formula. Furthermore, the cable dynamic coefficient is defined by considering the participation factors and the minimum number of vibration modes. The dynamic stiffness of the ISC is established by combining the static stiffness and cable dynamic coefficient. In addition, a shaking table test of a reduced-scale tower-line system model is performed to verify the correctness of the finite element model of the suspended cable. The results of the static and dynamic analyses indicate that the spring model based on the dynamic stiffness, showing a good precision, has a higher computational efficiency compared with the suspended cable model. Finally, the spring model, which is applied to the tower-line system by choosing different seismic excitations, inclinations, sag-to-span ratios, and spans of ISCs, is valid for an arbitrary angle of inclination ranging between 0° and 50°. Moreover, its results are in very good agreement with those of the suspended cable model.

Nonlinear shear analysis of I-shaped beams with arbitrary inclination angles of shear reinforcement

We studied the effect of the inclination angle of stirrups and wire mesh on the web-crushing strength of reinforced concrete I-beams beams. Experimental studies were carried out in Kuban State Technological University. The variable parameters of the tested specimens included concrete compressive strength, level of prestressing, cross-sectional shape, shear span, shear reinforcement ratio and angles of inclination of stirrups or wire mesh. The strength of beams was calculated with the Cyclic Softened Membrane Model for reinforced concrete (CSMM), developed at the University of Houston and implemented in the OpenSees software package. The modeling of the web of the beams was fulfilled with quadrilateral finite elements with the assigned material FAReinforcedConcretePlaneStress. The flanges of the beams resisting the bending moment were modeled with nonlinear volumetric elements having fiber section. Uniaxial Kent-Scott-Park concrete material and uniaxial bilinear steel material were assigned to the flanges. Calculation results are close to experimental data having wide variation of the materials properties and structural parameters of beams.

Intensity of stress singularity for the circumferential V‐shape corner front of a three‐dimensional diamond‐like defect

AbstractThree‐dimensional diamond‐like defects with circumferential V‐shape corner fronts are often contained in engineering materials. In this paper, generalized stress intensity factors are calculated for this type of defect using a modified advanced finite element method. A super corner front element model in the global coordinates is established to capture the stress singularities along the circumferential corner front. Three‐dimensional numerical series eigen‐solutions in the element have been transformed from asymptotic expressions in the local curvilinear coordinates. The element is suitable for a sharp V‐shape corner with arbitrary opening and inclination angle. Singular stress fields near various shapes of diamond‐like defects are systematically investigated. The interaction of an embedded defect with free surface or another identical defect is also investigated. The numerical results can be used as stress intensity parameters to predict fatigue strength at circumferential corner front of a diamond‐like defect.

Nonlinear Postbuckling of Eccentrically Oblique-Stiffened Functionally Graded Doubly Curved Shallow Shells Based on Improved Donnell Equations

The nonlinear buckling and postbuckling of eccentrically oblique-stiffened doubly curved shallow functionally graded shells is investigated based on improved Donnell equations. The improved Lekhnitskii smeared stiffeners technique is employed to found the stiffness matrix of the stiffened shells. The shells are reinforced by eccentrically oblique stiffeners with an arbitrary inclination angle. Using the Galerkin method, an analytical approximate solution for the deflection of reinforced FGM doubly curved shallow shells is obtained. The influence of geometrical parameters, oblique stiffeners, and temperature on the postbuckling behavior of the shells is analyzed.

A Statistical Channel Model for Stochastic Antenna Inclination Angles

The actions of a person holding a mobile device are not a static state but can be considered as a stochastic process since users can change the way they hold the device very frequently in a short time. The change in antenna inclination angles with the random actions will result in varied received signal intensity. However, very few studies and conventional channel models have been performed to capture the features. In this paper, the relationships between the statistical characteristics of the electric field and the antenna inclination angles are investigated and modeled based on a three-dimensional (3D) fast ray-tracing method considering both the diffraction and reflections, and the radiation patterns of an antenna with arbitrary inclination angles are deducted and included in the method. Two different conditions of the line-of-sight (LOS) and non-line-of-sight (NLOS) in the indoor environment are discussed. Furthermore, based on the statistical analysis, a semiempirical probability density function of antenna inclination angles is presented. Finally, a novel statistical channel model for stochastic antenna inclination angles is proposed, and the ergodic channel capacity is analyzed.

Free vibration analysis of transmission lines based on the dynamic stiffness method.

An improved mathematical model used to study the coupling characteristic of the multi-span transmission lines is developed. Based on the solution method for single-span cable, an expression for the dynamic stiffness of two-span transmission lines with an arbitrary inclination angle is formulated. The continuity of displacements and forces at a suspension point is used to derive the dynamic stiffness. Interactions between insulator strings and adjacent spans are accommodated. Considering the infinite dynamic stiffness corresponds to the natural frequencies of the transmission lines, the finite-element method (FEM) is employed to assess the validity of the dynamic stiffness. In the numerical investigation, attention is focused on the effect of the inclination angles, Irvine parameter, insulator string length and damping parameter. In addition, the modal function corresponding to the natural frequencies is derived. Then, the results of comprehensive parametric studies are presented and discussed. Special attention is paid to the effect of the Irvine parameter and damping parameter on the in-plane modal shapes. Finally, according to the theoretical model of two-span transmission lines, the generalized dynamic stiffness of transmission lines with an arbitrary number of spans and inclination angles is derived. The method can be used as the basis of the vibration analysis on a wide variety of multi-span transmission lines.

Evaluation of vortex identification methods based on two- and three-dimensional swirling strengths

Analytical solutions for two-dimensional (2D) and three-dimensional (3D) swirling strengths were derived and were used to simulate the detection of 3D vortices in planar Particle Image Velocimetry (PIV). Based on Euler’s rotation theorem and the Burgers vortex model, a general equation for the 2D swirling strength of a 3D vortex having an arbitrary inclination angle with the analyzed plane was proposed. Vortices were classified into two categories: strong vortices and weak vortices. When focusing only on strong vortices, previous studies reported that the ratio of the two swirling strengths varies as a sine function; however, we found that this ratio is a function of both circulation and inclination angle, and the relative deviation between the ratio function and the sine function exhibits a monotonous decrease with increasing circulation. When vortices are classified into different categories according to the circulation, the analytical solution fits well with data points in each category. Theoretical analysis reveals that the detection of a 3D vortex in planar PIV has a dependence on two factors (circulation and inclination angle) and the detection probability of a 3D vortex with a certain inclination angle in planar PIV was simulated. For example, detection probabilities of 3D vortices with inclination angles of 10°, 30°, 50°, and 90° are 10%, 46%, 81%, and 100%, respectively. To the best of author’s knowledge and study, the universally recognized assumption that only vortices with large inclination angles can be detected in planar PIV needs to be revised. For vortices with small inclination angles, as long as their circulation is sufficiently large, they can also be detected.

FDTD Analysis of Propagation and Absorption in Nonuniform Anisotropic Magnetized Plasma Slab

In this paper, a current density convolution finite-difference time-domain method is extended to study the electromagnetic wave propagation and absorption in inhomogeneous magnetized plasmas. First of all, we analyze the wave propagation in homogeneous magnetized plasmas for arbitrary magnetic inclination angle. Then, we studied three types of plasma absorption, including plasma resonance, electron cyclotron resonance, and upper hybrid resonance in homogeneous and inhomogeneous magnetized plasmas. This model is applied to simulate the heating mechanism during ionospheric modification experiments by high-power high-frequency radio waves. These results have important implications for the interpretation of physical mechanisms for the interaction of high power radio waves with magnetized ionospheric plasmas and design of future experiments.

Inclined Fiber Pullout from a Cementitious Matrix: A Numerical Study.

It is well known that fibers improve the performance of cementitious composites by acting as bridging ligaments in cracks. Such bridging behavior is often studied through fiber pullout tests. The relation between the pullout force vs. slip end displacement is characteristic of the fiber-matrix interface. However, such a relation varies significantly with the fiber inclination angle. In the current work, we establish a numerical model to simulate the entire pullout process by explicitly representing the fiber, matrix and the interface for arbitrary fiber orientations. Cohesive elements endorsed with mixed-mode fracture capacities are implemented to represent the bond-slip behavior at the interface. Contact elements with Coulomb’s friction are placed at the interface to simulate frictional contact. The bond-slip behavior is first calibrated through pull-out curves for fibers aligned with the loading direction, then validated against experimental results for steel fibers oriented at 30 and 60. Parametric studies are then performed to explore the influences of both material properties (fiber yield strength, matrix tensile strength, interfacial bond) and geometric factors (fiber diameter, embedment length and inclination angle) on the overall pullout behavior, in particular on the maximum pullout load. The proposed methodology provides the necessary pull-out curves for a fiber oriented at a given angle for multi-scale models to study fracture in fiber-reinforced cementitious materials. The novelty lies in its capacity to capture the entire pullout process for a fiber with an arbitrary inclination angle.

Approximate Expressions for the Magnetic Potential and Fields of 2-D, Asymmetrical Magnetic Recording Heads

A 2-D asymmetrical magnetic head is characterized by the parallel inclination of the semi-infinite, inner gap walls, and where the gap length and head-to-underlayer separation are small compared with the other dimensions in the head. With head corner inclination, these structures contribute to the reduction in the effective gap length of the head and, therefore, the increase in the field magnitude and narrowing of the field distributions near the acute gap corner. Asymmetrical heads were, therefore, proposed for increasing the writing and readout resolutions in gapped magnetic head structures. There are currently no explicit or approximate analytical solutions for the potential and fields from 2-D asymmetrical magnetic heads. This paper is concerned with the detailed theoretical derivation of relatively simple closed-form approximations for the scalar magnetic potential and fields from 2-D asymmetrical magnetic heads and their Fourier transforms, applicable to any arbitrary corner inclination angle. A general theory based on the translated sine Fourier series is developed to model and study the reaction of a soft magnetic underlayer on the surface potential of any magnetic head structure, and applied to the asymmetrical head. The approximate potential and field expressions derived in this paper demonstrated a very good agreement with the finite-element calculations of the 2-D asymmetrical heads.

Tidal truncation of inclined circumstellar and circumbinary discs in young stellar binaries

Recent observations have shown that circumstellar and circumbinary discs in young stellar binaries are often misaligned with respect to the binary orbital plane. We analyze the tidal truncation of such misaligned discs due to torques applied to the disc at the Lindblad resonances from the tidal forcings of the binary. We consider eccentric binaries with arbitrary binary-disc inclination angles. We determine the dependence of the tidal forcing strengths on the binary parameters and show that they are complicated non-monotonic functions of eccentricity and inclination. We adopt a truncation criterion determined by the balance between resonant torque and viscous torque, and use it to calculate the outer radii of circumstellar discs and the inner radii of circumbinary discs. Misaligned circumstellar discs have systematically larger outer radii than aligned discs, and are likely to fill their Roche lobes if inclined by more than $45^\circ - 90^\circ$, depending on the binary mass ratio and disc viscosity parameter. Misaligned circumbinary discs generally have smaller inner radii than aligned discs, but the details depend sensitively on the binary and disc parameters.

Plan oblique relief for web maps

Plan oblique relief shows terrain with a side view on a two-dimensional map, resulting in visualizations where the third dimension of the terrain is more explicit than on traditional two-dimensional maps. Existing plan oblique maps are static: the angle of terrain inclination is not adjustable and the orientation of plan oblique inclination does not change with the orientation of the map. This article introduces two complementary methods that address these issues by using the 3D graphics pipeline to render plan oblique relief for tile-based web maps. The goal is to allow users to adjust the terrain inclination and map rotation angles to better visualize the third dimension of the terrain. The first method pre-renders plan oblique tiles with a server-side application. The tiles are visualized with a standard web mapping framework. The second method renders plan oblique relief on-the-fly in a web browser using WebGL and a customized version of OpenLayers 3, which enables users to select arbitrary terrain inclination and map rotation angles. The second method uses a tiled digital terrain model that is loaded by the web browser. The browser applies the plan oblique transformation, computes a shaded relief, and texturizes the terrain with tiled map layers.