Plane Of Cylinder Research Articles

Statistical analysis of flow field variations via independent component analysis

The link between in-cylinder flow and subsequent combustion in a single-cylinder gasoline spark-ignition engine is analyzed via independent component analysis (ICA). Experimentally, the two in-plane components of the velocity are measured in the central cylinder plane by high-speed particle image velocimetry (PIV) with the engine running slightly lean at 1500 rpm in skip-fired mode. In 213 cycles, measurements are made during the late compression stroke before ignition with approximately 1° crank-angle temporal resolution. ICA then decomposes the set of 213 flow fields at each time step, yielding a set of “source” flow patterns—the independent components (IC). The temporal coherence between the ICs is then examined in a persistence analysis, comparing each IC with the one from the previous time step starting at ignition timing and going backwards in time. The results show which ICs persist how long throughout the compression stroke. To investigate the link between the ICs and combustion, the crank angle at which 10% of the fuel are burned (CA10) in each cycle is correlated with the extent to which a given IC can be found in each flow field. The most persistent IC can be traced over more than half of the 70 degrees crank angle over which images were acquired. The IC that correlates best with CA10 visually more resembles some of the flow features found in conditional averaging of fast-burning versus slow-burning cycles.

Study on Adhesion Force of Graphene under Cylinder–Plane Contact

There are many cylinder–plane contacts in microaccelerators, microgyroscopes, and RF switches. Adhesion is one of the main factors affecting the manufacture and use of these micro–nano devices, but its research is insufficient. Graphene is expected to be used in these fields due to its excellent electrical and mechanical properties. Therefore, it is significant to research the adhesion force of graphene under cylinder–plane. Firstly, the meniscus formation process was introduced using the variable-water-contact-angle method. Secondly, the adhesion force of the graphene surface was measured with a cylindrical atomic-force-microscope probe. Finally, the contact area was considered as a number of nanoscale cylinders in contact with the plane, and the adhesion force of the cylinder–plane model was obtained. The results showed that there was a maximum adhesion force at a relative humidity of 65%. The adhesion force was evidently not time-dependent when the relative humidity was below 45%, because the meniscus cannot be formed on the graphene surface at low relative humidity. While the graphene contact surface formed a meniscus for higher relative humidity, and the adhesion force-versus-time curves first increased and then decreased to stability. Moreover, the relationship between adhesion force and substrate contact angle, roughness, relative humidity, and dwell time was established, and the number of cylinders was determined. The error between the modified theoretical model and the experimental values was only 6%.

STUDY OF FLOW CHARACTERISTICS OVER HEATED PLAIN AND DUAL-STEP CYLINDERS

This work investigated flow past a dual-step cylinder at different wall temperatures, numerically and experimentally. The numerical work was carried out with the help of the computational fluid dynamics solver, Ansys Fluent. For validation, experiments were performed on a wind tunnel for the circular cylinder with step down (<i>D/d</i> < 1), step up (<i>D/d</i> > 1), and plane cylinder (<i>D/d</i> = 1). The drag coefficient was calculated based on the pressure measurements on peripheral points around all three cylinder cases. The results illustrate that the plain cylinder shows a maximum negative magnitude of pressure coefficient, whereas the step-down cylinder shows a minimum. The primary vortices interact with step-induced vortices clockwise and counterclockwise, producing different wake flow characteristics compared to the plane cylinder. Further, the results suggest that the ability to transfer heat from the cylinder wall to the fluid medium is higher for the cylinder with a diameter ratio of <i>D/d</i> < 1.

Stick-Slip Phenomena and Acoustic Emission in the Hertzian Linear Contact

AE detection and analysis usually requires a specific, costly platform due to its particular burst nature and high-frequency content. This experimental study investigates the relationship between low-demand acoustic emission parameters (AE) and the occurrence of stick–slip (SS) at the Hertzian linear contact. Hence, the correlation of basic AE characteristics (amplitude, energy, and evolution in time) with stick–slip characteristics (static and kinetic friction coefficients, amplitude, energy, and evolution in time) is pursued. Tribological tests were conducted on cylinder–plane specimens under dry friction conditions with different loads at different low driving speeds and Hertzian contact pressures at a constant stiffness. The AE, normal, and friction forces were recorded simultaneously on the experimental stand. At the cylinder–plane interface, the jumps specific to the stick–slip phenomenon (friction coefficient—COF) were followed after a few milliseconds by AE jump peaks. The results of the experiments show that the amplitude and energy generated by AE were sensitive to the occurrence of the stick–slip phenomenon, while the AE and COF energies in the stick and slip phases had the same law of variation based on the driving velocities. The results show that the amplitude and energy of the sampled low-frequency AE signals were enough to detect the friction in SS and demonstrate the potential of AE as a tool for detecting and monitoring the tribological behaviour of SS at the linear Hertzian contact.

A New Dual-Mode Wear Model of Abrasion–Fatigue for Plane (100Cr6)-Cylinder (C45E4) Steel Pairs With Fractal Surfaces

Understanding dual-mode wear behavior, including fatigue and abrasive wear, is essential for determination of surface damage under the sliding-impact condition, which can induce early motion-pair failure. A new dual-mode wear model is presented in this article for plane–cylinder contact pairs with fractal surfaces. First, fractal theory is employed for elastic–plastic contact analysis of the mating surfaces. Then the negative inhibitory effect of the abrasive surface damage on subsurface fatigue crack propagation is considered to explore abrasion–fatigue interactions at the asperity level. Subsequently, dual-mode wear behaviors are derived for the asperity and fractal surface based on four wear-combination scenarios of the abrasive and fatigue mechanisms. Furthermore, the validity of the proposed prediction model is evaluated by comparisons between the expected results and laboratory tests with 100Cr6 plane and C45E4 cylinder steel pairs. The results show that the new model can reasonably explain the dual mode wear behavior and predict the wear rate of friction pairs. These insights can potentially help in guiding the tribological design of these dual-mode wear scenarios.

Elastoplastic Equilibrium of a Hollow Cylinder from an Inhomogeneous Perfectly Plastic Material

The article deals with the axisymmetric elastoplastic problem for a hollow thick-walled cylinder (plane deformed state), loaded from the inside and outside by uniform pressures proportional to one parameter. The material is considered to be perfectly plastic, with the elastic modulus and yield strength generally are arbitrary functions of the radius. In addition, the material is considered to be incompressible in both plastic and elastic zones. On the basis of the criteria for the plasticity of Huber - Mises and Tresca - Saint-Venant, the radius at which the first plastic deformations occur is determined. It is shown that, depending on the functions of the inhomogeneity of elastic and plastic parameters and loads, the occurrence of plastic deformations is possible both on the surfaces and on the inner walls of the cylinder.

Coupling of components at plane–cylinder surfaces

The mating of components at plane–cylinder surfaces is studied, by simulation. The influence of the shape and positional precision of the coupled surfaces on the relative position of the components is analyzed.

A hollow cylindrical linear nut-type ultrasonic motor

A hollow, linear, nut-type, ultrasonic motor based on two degenerate, 3 rd -order bending modes in the section plane of cylinders is presented in this paper. The stator and rotor of the motor are both cylindrical and hollow, making the motor appropriate for applications where a light path, electric wire or optic fiber is required to pass through the motor. A new structure with four PZT plates bonded on the stator is proposed here. and the other had all eight sides bonded with PZT plates. The results show that the new design with four PZT plates has a higher mechanical quality factor, vibrates with larger amplitude, and has comparable performance to the stator with eight PZT plates. The motor with four PZT plates reached an upward speed of 0.95 mm/s when the load force was 3 g, and the maximum thrust force was 0.35 N. DOI: http://dx.doi.org/10.5755/j01.mech.22.6.13366

Particle Internal Fracture Energy Measurement by Ultrafast Load Cell

Ultrafast Load Cell (UFLC) device is used in micro-scale modeling of particle fracture. Electro-mechanical device measures the internal fracture energy of the particles during the fracture event under impact. The sphere and/or cylinder weight is dropped onto particle staying on a plane cylinder surface. The point where the particle is divided into two pieces without secondary, tertiary breakages is called the fracture point. UFLC is equipped with two Wheatstone bridges. These bridges convert compressive strain signals produced during the impact event to a voltage signal. This signal can be expressed as force, energy, and displacement. All the information gained during the fracture is then used to estimate breakage rates of the particles. In this study, two parameter Weibull distribution is used in modeling the internal fracture energy distributions of the particles those ranges between 7mm and 45mm. It is concluded from the study that the median internal specific fracture energy of the particles of the size 45mm and 7mm are 2.2 Joule /kg and 25.4 Joule /kg, respectively. This study quantitatively shows the relationship between the particle specific fracture energy and the size.

An Improved Attributed Scattering Model Optimized by Incremental Sparse Bayesian Learning

In this paper, we propose an improved attributed scattering model to mathematically unify the scattering models of several canonical primitives. These primitives include not only point- and line-segment-scatterers, such as trihedral, cylinder, dihedral, and rectangular plane, but also arc scatterers, such as sphere and top-hat. The estimation of the model parameters can be posed as an ill-posed linear inverse problem. To overcome the ill-posedness, we employ the incremental sparse Bayesian learning method to realize the sparsity-driven continuous parameter estimation. Inverse scattering experiments demonstrate that the proposed methodology not only provides desirable sparse representations of the target scattering response but is also able to capture richer geometrical information than the existing models.

Axisymmetric Thermo-elastic Deformation of the Cylinder with Two-dimensional Inhomogeneity of Material

The article discusses the use of a numerical method the calculation of finite cylinders into account the dependence of physical and mechanical properties of the material on temperature. If we have two-dimensional temperature field characteristics of the material depends on two coordinates. - r and z from which follows that the problem of thermoelasticity is also a two-dimensional. Using the numerical method allows to solve the problem for any state of the cylinder (plane stress or plane strain) and consider arbitrary boundary conditions at its ends.

Axisymmetric Thermo-elastic Deformation of the Cylinder with Two-dimensional Inhomogeneity of Material

The article discusses the use of a numerical method the calculation of finite cylinders into account the dependence of physical and mechanical properties of the material on temperature. If we have two-dimensional temperature field characteristics of the material depends on two coordinates. - and from which follows that the problem of thermoelasticity is also a two-dimensional. Using the numerical method allows to solve the problem for any state of the cylinder (plane stress or plane strain) and consider arbitrary boundary conditions at its ends.

Acoustic radiation force on a rigid elliptical cylinder in plane (quasi)standing waves

The acoustic radiation force on a 2D elliptical (non-circular) cylinder centered on the axis of wave propagation of plane quasi-standing and standing waves is derived, based on the partial-wave series expansion (PWSE) method in cylindrical coordinates. A non-dimensional acoustic radiation force function, which is the radiation force per unit length, per characteristic energy density and per unit cross-sectional surface of the ellipse, is defined in terms of the scattering coefficients that are determined by applying the Neumann boundary condition for an immovable surface. A system of linear equations involving a single numerical integration procedure is solved by matrix inversion. Numerical simulations showing the transition from the quasi-standing to the (equi-amplitude) standing wave behaviour are performed with particular emphasis on the aspect ratio a/b, where a and b are the ellipse semi-axes, as well as the dimensionless size parameter kb (where k is the wavenumber), without the restriction to a particular range of frequencies. It is found that at high kb values > 1, the radiation force per length with broadside incidence is larger, whereas the opposite situation occurs in the long-wavelength limit (i.e., kb < 1). The results are particularly relevant in acoustic levitation of elliptical cylinders, the acoustic stabilization of liquid columns in a host medium, acousto-fluidics devices, and other particle dynamics applications to name a few. Moreover, the formalism presented here may be effectively applied to compute the acoustic radiation force on other 2D surfaces of arbitrary shape such as super-ellipses, Chebyshev cylindrical particles, or other non-circular geometries.

SU‐E‐I‐16: Scan Length Dependency of the Radial Dose Distribution in a Long Polyethylene Cylinder

Purpose:The area‐averaged dose in the central plane of a long cylinder following a CT scan depends upon the radial dose distribution and the length of the scan. The ICRU/TG200 phantom, a polyethylene cylinder 30 cm in diameter and 60 cm long, was the subject of this study. The purpose was to develop an analytic function that could determine the dose for a scan length L at any point in the central plane of this phantom.Methods:Monte Carlo calculations were performed on a simulated ICRU/TG200 phantom under conditions of cylindrically symmetric conditions of irradiation. Thus, the radial dose distribution function must be an even function that accounts for two competing effects: The direct beam makes its weakest contribution at the center while the scatter begins abruptly at the outer radius and grows as the center is approached. The scatter contribution also increases with scan length with the increase approaching its limiting value at the periphery faster than along the central axis. An analytic function was developed that fit the data and possessed these features.Results:Symmetry and continuity dictate a local extremum at the center which is a minimum for the ICRU/TG200 phantom. The relative depth of the minimum decreases as the scan length grows and an absolute maximum can occur between the center and outer edge of the cylinders. As the scan length grows, the relative dip in the center decreases so that for very long scan lengths, the dose profile is relatively flat.Conclusion:An analytic function characterizes the radial and scan length dependency of dose for long cylindrical phantoms. The function can be integrated with the results expressed in closed form. One use for this is to help determine average dose distribution over the central cylinder plane for any scan length.

Effect of effective lens position on cylinder power of toric intraocular lenses

ObjectiveTo evaluate the effects of effective lens position (ELP) on the corneal plane effective cylinder power of toric intraocular lenses (IOLs). DesignRetrospective cross-sectional study. ParticipantsNinety-four eyes from 78 patients who underwent uncomplicated phacoemulsification with implantation of an AcrySof toric IOL (1.50- to 3.00-D cylinder). MethodsThe amount of corneal plane effective cylinder power of toric IOLs given by the manufacturer (target-induced astigmatism vector [TIA]) was compared with the postoperatively achieved cylindrical correction (surgically induced astigmatism vector [SIA]). The theoretical corneal plane cylinder power of toric IOLs was calculated according to ELP and corneal power using a refractive vergence formula. ResultsThe TIA (1.59 ± 0.43 D) was significantly smaller than the SIA (1.78 ± 0.65 D; p < 0.001). The difference between the magnitudes of SIA and TIA demonstrated a significant negative correlation with ELP (r = –0.219 and p = 0.034). The theoretical corneal plane cylinder power of toric IOLs demonstrated a decreasing trend as the ELP and corneal power increased. The range of changes in corneal plane effective cylinder power according to ELP and corneal power was greater in toric IOLs with high toricity. ConclusionsThe cylinder power of AcrySof toric IOLs should be adjusted according to ELP. For eyes with small ELP, the cylinder power should be reduced, and for eyes with large ELP, the cylinder power should be increased. The amount of reducing or increasing cylinder power of toric IOLs should be increased as the toricity increases.

SU‐F‐18C‐11: Diameter Dependency of the Radial Dose Distribution in a Long Polyethylene Cylinder

Purpose:The radial dose distribution in the central plane of a long cylinder following a long CT scan depends upon the diameter and composition of the cylinder. An understanding of this behavior is required for determining the spatial average of the dose in the central plane. Polyethylene, the material for construction of the TG200/ICRU phantom (30 cm in diameter) was used for this study. Size effects are germane to the principles incorporated in size specific dose estimates (SSDE); thus diameter dependency was explored as well.Method:ssuming a uniform cylinder and cylindrically symmetric conditions of irradiation, the dose distribution can be described using a radial function. This function must be an even function of the radial distance due to the conditions of symmetry. Two effects are accounted for: The direct beam makes its weakest contribution at the center while the contribution due to scatter is strongest at the center and drops off abruptly at the outer radius. An analytic function incorporating these features was fit to Monte Carlo results determined for infinite polyethylene cylinders of various diameters. A further feature of this function is that it is integrable.Results:Symmetry and continuity dictate a local extremum at the center which is a minimum for the larger sizes. The competing effects described above can Resultin an absolute maximum occurring between the center and outer edge of the cylinders. For the smallest cylinders, the maximum dose may occur at the center.Conclusion:An integrable, analytic function can be used to characterize the radial dependency of dose for cylindrical CT phantoms of various sizes. One use for this is to help determine average dose distribution over the central cylinder plane when equilibrium dose has been reached.

Dynamics of a flexible splitter plate in the wake of a circular cylinder

Rigid splitter plates in the wake of bluff bodies are known to suppress the primary vortex shedding. In the present work, we experimentally study the problem of a flexible splitter plate in the wake of a circular cylinder. In this case, the splitter plate is free to continuously deform along its length due to the fluid forces acting on it; the flexural rigidity (EI) of the plate being an important parameter. Direct visualizations of the splitter plate motions, for very low values of flexural rigidity (EI), indicate periodic traveling wave type deformations of the splitter plate with maximum tip amplitudes of the order of 1 cylinder diameter. As the Reynolds number based on cylinder diameter is varied, two regimes of periodic splitter plate motions are found that are referred to as mode I and mode II, with a regime of aperiodic motions between them. The frequency of plate motions in both periodic modes is found to be close to the plane cylinder Strouhal number of about 0.2, while the average frequencies in the non-periodic regime are substantially lower. The measured normalized phase speed of the traveling wave for both periodic modes is also close to the convection speed of vortices in the plane cylinder wake. As the flexural rigidity of the plate (EI) is increased, the response of the plate was found to shift to the right when plotted with flow speed or Re. To better capture the effect of varying EI, we define and use a non-dimensional bending stiffness, K⁎, similar to the ones used in the flag flutter problem, K⁎=EI/(0.5ρU2L3), where U is the free-stream velocity and L is the splitter plate length. Amplitude data for different EI cases when plotted against this parameter appear to collapse on to a single curve for a given splitter plate length. Measurements of the splitter plate motions for varying splitter plate lengths indicate that plates that are substantially larger than the formation length of the plane cylinder wake have similar responses, while shorter plates show significant differences.

MODE SUMMATION APPROACH TO CASIMIR EFFECT BETWEEN TWO OBJECTS

In the last few years, several approaches have been developed to compute the exact Casimir interaction energy between two nonplanar objects, all lead to the same functional form, which is called the TGTG formula. In this paper, we explore the TGTG formula from the perspective of mode summation approach. Both scalar fields and electromagnetic fields are considered. In this approach, one has to first solve the equation of motion to find a wave basis for each object. The two T's in the TGTG formula are [Formula: see text]-matrices representing the Lippmann–Schwinger T-operators, one for each of the objects. Each [Formula: see text]-matrix can be found by matching the boundary conditions imposed on the object, and it is independent of the other object. However, it depends on whether the object is interacting with an object outside it, or an object inside it. The two G's in the TGTG formula are the translation matrices, relating the wave basis of an object to the wave basis of the other object. These translation matrices only depend on the wave basis chosen for each object, and they are independent of the boundary conditions on the objects. After discussing the general theory, we apply the prescription to derive the explicit formulas for the Casimir energies for the sphere–sphere, sphere–plane, cylinder–cylinder and cylinder–plane interactions. First the [Formula: see text]-matrices for a plane, a sphere and a cylinder are derived for the following cases: the object is imposed with Dirichlet, Neumann or general Robin boundary conditions; the object is semitransparent; and the object is a magnetodielectric object immersed in a magnetodielectric media. Then the operator approach developed by R. C. Wittman [IEEE Trans. Antennas Propag.36, 1078 (1988)] is used to derive the translation matrices. From these, the explicit TGTG formula for each of the scenarios can be written down. On the one hand, we have summarized all the TGTG formulas that have been derived so far for the sphere–sphere, cylinder–cylinder, sphere–plane and cylinder–plane configurations. On the other hand, we provide the TGTG formulas for some scenarios that have not been considered before.

PANORAMIC EPIPOLAR IMAGE GENERATION FOR MOBILE MAPPING SYSTEM

Abstract. The notable improvements on performance and low cost of digital cameras and GPS/IMU devices have caused MMSs (Mobile Mapping Systems) to be gradually becoming one of the most important devices for mapping highway and railway networks, generating and updating road navigation data and constructing urban 3D models over the last 20 years. Moreover, the demands for large scale visual street-level image database construction by the internet giants such as Google and Microsoft have made the further rapid development of this technology. As one of the most important sensors, the omni-directional cameras are being commonly utilized on many MMSs to collect panoramic images for 3D close range photogrammetry and fusion with 3D laser point clouds since these cameras could record much visual information of the real environment in one image at field view angle of 360° in longitude direction and 180° in latitude direction. This paper addresses the problem of panoramic epipolar image generation for 3D modelling and mapping by stereoscopic viewing. These panoramic images are captured with Point Grey’s Ladybug3 mounted on the top of Mitsubishi MMS-X 220 at 2m intervals along the streets in urban environment. Onboard GPS/IMU, speedometer and post sequence image analysis technology such as bundle adjustment provided high accuracy position and attitude data for these panoramic images and laser data, this makes it possible to construct the epipolar geometric relationship between any two adjacent panoramic images and then the panoramic epipolar images could be generated. Three kinds of projection planes: sphere, cylinder and flat plane are selected as the epipolar images’ planes. In final we select the flat plane and use its effective parts (middle parts of base line’s two sides) for epipolar image generation. The corresponding geometric relations and results will be presented in this paper.

The Theoretical Solutions of Several Integrations in Relation with the Plane Wave Functions

Several integrations of the plane wave functions frequently appearing in the scattering problems of elastic waves are considered in this study. In conjunction with the principle of superposition and the stationary wave function expansion, the exact solutions are obtained. As in the scattering problems of elastic waves and plane waves, the theoretical solutions can improve the convergence speed of the arithmetic and the computation precision. The analysis method and the analytical solutions can also be very helpful to solving other complex integrations in relation with the cylinder functions and plane functions.