First-Order Eikonal Model Analysis for 12C+12C and 16O+16O Elastic Scatterings and the Tangential Velocity Effect

In this paper, analytical and numerical analyses of radial and tangential velocities and pressure of lubricant film have been considered in an eccentric journal bearing. A 2D flow of shear-thinning viscous fluid is followed by Carreau-Yasuda mathematical model between two eccentric cylinders. The model is mathematically conserved from eccentric coordinate to concentric coordinate due largely to easy solution. Therefore, the PDE equations were converted to the ODE equations with a set of nonlinear algebraic first order equations with their boundary conditions. These kinds of equations are called boundary value problems (BVP) that can be solved with shooting method. The results are compared with 2D numerical simulation in the Fluent software. Lubricant tangential velocity and pressure distributions are examined in the dynamic journal bearing. The comparison of the results revealed that numerical analysis as same as analytical approach is a reliable method for determining lubricant motion in the gap.

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Factors Influencing the Measurement of Slipperiness

Proceedings of the Human Factors Society Annual Meeting ◽

10.1177/154193128803200906 ◽

1988 ◽

Vol 32 (9) ◽

pp. 545-548 ◽

Cited By ~ 1

Author(s):

Mark S. Redfern

Keyword(s):

Coefficient Of Friction ◽

Interaction Effect ◽

Vertical Force ◽

Dynamic Tests ◽

Order Interaction ◽

First Order ◽

Factors Influencing ◽

Different Types ◽

Velocity Effect

The evaluation and prevention of slips and falls require methods of quantifying the slipperiness of floors. The concept of coefficient of friction (COF) has been and continues to be commonly used as one such method. The objective of this paper is to present some results from investigations into the effects of vertical force and velocity on COF measures for different types of floors. Tests involving both static COF (SCOF) and dynamic COF (DCOF) measurements were performed under various conditions. It was found that the SCOF changed as a function of the vertical force used. Generally, the SCOF increased as the vertical force was increased. This was not true, however, for tile floors. It was also found that there was a significant first order interaction effect on the SCOF between vertical weight and the condition of the floor (wet or dry). The dynamic tests showed that velocity of the shoe material with respect to the floor had a large effect on the DCOF values obtained. The velocity effect was dependent on the shoe material and the conditions tested. Possible reasons for these findings and ramifications on slip testing are presented.

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ANALYTIC FIRST-ORDER EIKONAL MODEL FOR HEAVY-ION ELASTIC SCATTERINGS

International Journal of Modern Physics E ◽

10.1142/s0218301310016430 ◽

2010 ◽

Vol 19 (10) ◽

pp. 1947-1960

Author(s):

YONG JOO KIM ◽

JONG-KWAN WOO ◽

MOON HOE CHA

Keyword(s):

Phase Shift ◽

Cross Sections ◽

Theoretical Method ◽

Heavy Ion ◽

Reaction Cross ◽

Order Correction ◽

Model Calculations ◽

First Order ◽

Eikonal Model ◽

First Order Correction

We present analytic expressions for the zero-order eikonal phase shift and its first-order correction by approximating a distance between two colliding nuclei. This formalism has been applied to elastic scatterings of the 12 C + 40 Ca and the 12 C + 90 Zr systems at E lab = 420 MeV , and the 16 O + 40 Ca and the 16 O + 90 Zr ones at E lab = 1503 MeV . The calculated angular distributions, taking into account up to the analytic first-order eikonal phase shift, are found to be in fairly good agreement with the observed data. The reaction cross-sections obtained from the present model produce very excellent agreements with ones of exact first-order eikonal model calculations. We have found that analytic eikonal phase shift including the first-order correction is one theoretical method to the analysis of heavy-ion elastic scattering.

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The Effect Of Tangential Velocity Component In Abrasive Jet Micro-Machining Of Borosilicate Glass

10.32920/14646546.v1 ◽

2021 ◽

Author(s):

Md. A. Hasem

Keyword(s):

Borosilicate Glass ◽

Velocity Component ◽

Tangential Velocity ◽

Micro Machining ◽

Target Holder ◽

Air Blast ◽

Tangential Velocity Component ◽

Erosion Testing ◽

Oxide Particles ◽

Velocity Effect

Generally two types of erosion testers are used in solid particle erosion testing: air blast erosion testers and mechanically powered erosion testers. In the first portion of this thesis, the feasibility of implementing a mechanically powered erosion tester for abrasive jet micro-machining applications using very small particles was studied. It was found that, due to the ultrahigh vacuum requirement, such a device would not be practical. Therefore, in the second part of the thesis, the designed rotary mechanism was utilized as a rotary disc target holder apparatus and blasted with a typical air blast system. The apparatus could add or deduct a tangential velocity component into the system, allowing for detailed studies of the effect that the tangential velocity component has on the erosion of borosilicate glass using 25-150 μm aluminum oxide particles. Although the tangential velocity effect has been ignored for brittle materials by most researchers, the present results show that it can have an important role in erosion rate.Generally two types of erosion testers are used in solid particle erosion testing: air blast erosion testers and mechanically powered erosion testers. In the first portion of this thesis, the feasibility of implementing a mechanically powered erosion tester for abrasive jet micro-machining applications using very small particles was studied. It was found that, due to the ultrahigh vacuum requirement, such a device would not be practical. Therefore, in the second part of the thesis, the designed rotary mechanism was utilized as a rotary disc target holder apparatus and blasted with a typical air blast system. The apparatus could add or deduct a tangential velocity component into the system, allowing for detailed studies of the effect that the tangential velocity component has on the erosion of borosilicate glass using 25-150 μm aluminum oxide particles. Although the tangential velocity effect has been ignored for brittle materials by most researchers, the present results show that it can have an important role in erosion rate.

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Second-Order Eikonal Model Analysis for the $pi^{pm}$+$^{12}$C Elastic Scattering at $p$=995 MeV/c

Journal of the Korean Physical Society ◽

10.3938/jkps.56.1430 ◽

2010 ◽

Vol 56 (5) ◽

pp. 1430-1435 ◽

Cited By ~ 2

Author(s):

Yong Joo Kim ◽

Jong-Kwan Woo ◽

Moon Hoe Cha

Keyword(s):

Elastic Scattering ◽

Model Analysis ◽

Second Order ◽

Eikonal Model

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Eikonal model analysis of 240 MeV 6Li elastic scattering on 24Mg and 28Si

Journal of the Korean Physical Society ◽

10.3938/jkps.60.1477 ◽

2012 ◽

Vol 60 (9) ◽

pp. 1477-1480 ◽

Cited By ~ 2

Author(s):

Yong Joo Kim ◽

Jong-Kwan Woo ◽

Seok Jae Lee

Keyword(s):

Elastic Scattering ◽

Model Analysis ◽

Eikonal Model

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Tangential Velocity Corrections to a Second-Order Coulomb-Modified Eikonal Model for Heavy-Ion Elastic Scattering

International Journal of Modern Physics E ◽

10.1142/s0218301303001399 ◽

2003 ◽

Vol 12 (04) ◽

pp. 479-492

Author(s):

Yong Joo Kim ◽

Moon Hoe Cha

Keyword(s):

Experimental Data ◽

Elastic Scattering ◽

Tangential Velocity ◽

Heavy Ion ◽

Second Order ◽

Angular Distributions ◽

Asymptotic Velocity ◽

Imaginary Potential ◽

Eikonal Model ◽

Potential Strength

We present the tangential velocity corrections to the second-order Coulomb-modified eikonal model at the distance of closest approach. It has been applied to elastic angular distributions of the 16 O +16 O system at E lab =350 and 480 MeV. The calculated results with tangential velocity show better agreements with the experimental data compared to those with asymptotic velocity. The Fraunhöfer oscillations observed in the elastic angular distributions can be explained by the strong interference between the near- and the far-side amplitudes. Airy structures can be shown by reducing the effective imaginary potential strength. It is found that the Airy minimum is more visible as the effective imaginary potential strength is reduced. Deep real potentials associated with rather weak imaginary ones are found to be essential to describe the refractive 16 O +16 O elastic scatterings at E lab =350 and 480 MeV.

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