Factors Affecting the Accurate Measurement of Laser Beam Width with CCD Camera

Abstract Background Screw breakage and loosening are the most common mechanical complications associated with implant treatment, and they may occur due to excess or inadequate screw tightening torque. When fastening and fixing the implant superstructure, screws are tightened using a torque wrench, which is essential for an accurate tightening force. However, the characteristics of the torque wrench have not been fully verified. Therefore, we aimed to clarify the factors affecting the torque with a focus on beam-type torque wrenches, which are the main types of wrenches. Methods The torque values generated by beam-type torque wrenches from eight manufacturers were measured using a torque gauge. To investigate the influence of the location of the beam relative to the scale, measurements were performed with a scale aligned with the trailing edge, center, and leading edge of the beam respectively. Additionally, measurements were taken at 90°, 60°, and 30° to examine the effect of the angle at which the examiner read the torque value. Under each condition, a single examiner applied the recommended torque to each manufacturer's screws five times in a clockwise direction. The average measured torque, standard deviation, bias, and coefficient of variation were calculated and compared accordingly. Results Wrenches from six manufacturers demonstrated excellent accuracy for measurements at the center of the beam (bias within ± 4%). For measurements at 90°, equipments from five manufacturers displayed excellent accuracy (bias within ± 7%), and seven showed excellent repeatability (coefficient of variation ≤ 2%). Conclusion The scale should be aligned with the center of the beam and read from 90° while using a torque wrench. The accuracy and repeatability torques generated by the wrenches differed according to the manufacturer, scale width, scale line width, beam width, and distance between the scale and beam center. Based on these results, we suggest that a torque wrench must be selected after determining the difference in the structure of the torque wrench.

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Self-Focusing of Hermite-Cosh-Gaussian Laser Beams in Plasma under Density Transition

Advances in Optics ◽

10.1155/2014/942750 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 8

Author(s):

Manzoor Ahmad Wani ◽

Niti Kant

Keyword(s):

Laser Beam ◽

Plasma Density ◽

Focal Spot ◽

Beam Width ◽

Spot Size ◽

Laser Beams ◽

Equation Approach ◽

Focal Spot Size ◽

Self Focusing ◽

Small Spot

Self-focusing of Hermite-Cosh-Gaussian (HChG) laser beam in plasma under density transition has been discussed here. The field distribution in the medium is expressed in terms of beam-width parameters and decentered parameter. The differential equations for the beam-width parameters are established by a parabolic wave equation approach under paraxial approximation. To overcome the defocusing, localized upward plasma density ramp is considered, so that the laser beam is focused on a small spot size. Plasma density ramp plays an important role in reducing the defocusing effect and maintaining the focal spot size up to several Rayleigh lengths. To discuss the nature of self-focusing, the behaviour of beam-width parameters with dimensionless distance of propagation for various values of decentered parameters is examined by numerical estimates. The results are presented graphically and the effect of plasma density ramp and decentered parameter on self-focusing of the beams has been discussed.

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Research on Powder Stream of Coaxial Powder Feeding in Laser Manufacturing Technology

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.423-426.807 ◽

2013 ◽

Vol 423-426 ◽

pp. 807-810

Author(s):

Heng Quan ◽

Yun Shan Wang ◽

Li Feng Liu ◽

Shao Jun Liu ◽

Qing Ruo Meng

Keyword(s):

Physical Model ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Concentration Field ◽

Ccd Camera ◽

Factors Affecting ◽

Coaxial Nozzle ◽

Powder Mass ◽

Powder Feeding

Mathematical-physical model of powder stream in coaxial powder feeding was established. The concentration fields of powder stream of coaxial nozzle of different size and powder mass flow rate were analyzed. The concentration field and morphology of the powder stream were detected by CCD camera. The results show that the size of coaxial nozzle and powder mass flow rate are major factors affecting the powder stream. The mathematical-physical model and experimental data provide theoretical basis for laser cladding manufacturing.

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Relativistic ponderomotive self-focusing of quadruple Gaussian laser beam in cold quantum plasma

Laser and Particle Beams ◽

10.1017/s026303461800023x ◽

2018 ◽

Vol 36 (3) ◽

pp. 353-358 ◽

Cited By ~ 5

Author(s):

Richa ◽

Munish Aggarwal ◽

Harish Kumar ◽

Ranju Mahajan ◽

Navdeep Singh Arora ◽

...

Keyword(s):

Refractive Index ◽

Laser Beam ◽

Electron Temperature ◽

Density Perturbation ◽

Beam Width ◽

Quantum Plasma ◽

Gaussian Laser Beam ◽

Self Focusing ◽

Linear Differential ◽

Paraxial Ray

AbstractIn the present paper, we have investigated self-focusing of the quadruple Gaussian laser beam in underdense cold quantum plasma. The non-linearity chosen is associated with the relativistic mass effect that arises due to quiver motion of electron and electron density perturbation caused by ponderomotive force. The non-linearity modifies the plasma frequency in the dielectric function and hence the refractive index of the medium. The focusing/defocusing of the quadruple laser depends on the refractive index of the medium. We have set up non-linear differential equation that controls the beam width parameter by using well-known paraxial ray approximation and Wentzel–Krammers–Brillouin approximation. The effect of intensity parameter and electron temperature is observed on laser beam self-focusing in the presence of cold quantum plasma. From the results, it is revealed that electron temperature and the initial intensity of the laser beam control the profile dynamics of the laser beam.

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The analysis of atmospheric factors affecting the value of vertical refraction angle with the assessment of the importance of introduction of the atmospheric amendment

E3S Web of Conferences ◽

10.1051/e3sconf/20187100019 ◽

2018 ◽

Vol 71 ◽

pp. 00019

Author(s):

Paulina Kaczor

Keyword(s):

Laser Beam ◽

Atmospheric Correction ◽

Refraction Angle ◽

Factors Affecting ◽

Number Of Factors ◽

Four Seasons ◽

Vertical Displacements ◽

Opencast Mines ◽

Atmosphere Density ◽

Atmospheric Factors

The study of vertical displacements of hydrotechnical objects, slender constructions, opencast mines or flotation waste reservoirs often requires continuous geodetic monitoring, which in real time defines potential threats resulting from changes in the geometry of the object. In order to ensure high accuracy in determining vertical displacements, a precise robotic tacheometer is used as one of the monitoring sensors. In the case of trigonometric leveling, the quality of measurements is affected not only by the accuracy of the instrument, but also by the centre through which the laser beam emitted by it passes. The radius emitted by the tacheometer due to the layered structure of the atmosphere is deflected, and the angle that it creates with the theoretical course of rays is called the angle of vertical refraction. In order to eliminate the influence of this type of errors, so-called atmospheric correction is introduced to all tacheometric measurements. Currently, total stations automatically determine and introduce corrections for observation, usually using only air temperature and atmospheric pressure. However, the number of factors responsible for the change in atmosphere density, and thus the deflection of the laser beam is much greater. And its influence is also affected by the length of the target and roughness of the area over which the measurement is made. The paper presents the analysis of the significance of various atmospheric and terrain factors that may affect the value of the vertical refraction angle. By the multiple regression method, with the use of the analyzed factors, equations describing the phenomenon of vertical refraction for four seasons have been designated. The defined equation coefficients were used to determine the refraction angle for the observations recorded on the post-flotation waste tank. To confirm the rightness of introducing an additional atmospheric correction, analyses were performed showing the percentage of corrected results.

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INVESTIGATION OF PECULIARITIES OF LIGHT SCATTERING BY NANOSTRUCTURAL CHANGES IN THE CRYSTAL LATTICE OF FERROELECTRIC BARIUM SODIUM NIOBATE CRYSTAL

International Journal of Nanoscience ◽

10.1142/s0219581x0400270x ◽

2004 ◽

Vol 03 (06) ◽

pp. 815-818 ◽

Cited By ~ 1

Author(s):

S. V. IVANOVA

Keyword(s):

Light Scattering ◽

Laser Beam ◽

Beam Width ◽

Far Field ◽

Sodium Niobate ◽

Incident Laser Beam ◽

Incident Laser ◽

Elastic Light Scattering ◽

Temperature Range ◽

Thermal Changes

Thermal changes of light scattering images in the far-field were observed under steady illumination by an incident laser beam of finite beam width on barium sodium niobate crystals in the temperature range of 20–500°C. Different patterns of light scattering in far-field were observed — from striped to round-like form with dependence on temperature, conditions of grown, direction of beam and polarization. The round-like form was observed on cooling from 450°C to 240°C. Striped forms of light scattering were observed below 200°C. Correlation of the behavior of elastic light scattering was observed in this temperature range.

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Techniques for accurately measuring laser beam width with commercial CCD cameras

10.1117/12.312711 ◽

1998 ◽

Cited By ~ 4

Author(s):

Carlos B. Roundy

Keyword(s):

Laser Beam ◽

Beam Width ◽

Ccd Cameras

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Investigation into LST and its Novel Application in Mould

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.24-25.189 ◽

2007 ◽

Vol 24-25 ◽

pp. 189-194

Author(s):

Yun Wang ◽

Z.Y. Xu ◽

Y.H. Fu ◽

Lan Cai

Keyword(s):

Laser Beam ◽

Material Removal ◽

Surface Engineering ◽

Surface Texturing ◽

Industrial Applications ◽

Laser Surface Texturing ◽

Intense Laser ◽

Full Potential ◽

Workpiece Surface ◽

Factors Affecting

Laser surface texturing (LST) technology that is firstly used in rollers, is a specialized surface engineering process capable of enhancing the surface material properties, wear resistance, fretting fatigue life and reducing friction. This practical technology of the LST process is based on a pulsating laser beam that, by material ablation, generates the optimum topographical surface. In order to exploit the full potential of the process, a great amount of research has explored from the material removal mechanics to the development of the LST process. This paper reports on the LST research involving the LST technology surveying process optimization, LST equipment and its industrial applications. The paper also highlights the forming theory describing the skin-pass process of transferring the textured roller’s surface structure onto the steel sheet, and the laser-matter interaction that occurs when and intense laser beam is tightly focused in the workpiece surface. It presents the influence of various factors affecting the textured workpiece performance together with the investigations into tribology of textured components. The paper also discusses these developments and some fundamental on future LST research.

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Dynamics of Gaussian spikes on Gaussian laser beam in relativistic plasma

Laser and Particle Beams ◽

10.1017/s0263034609990309 ◽

2009 ◽

Vol 27 (4) ◽

pp. 587-593 ◽

Cited By ~ 9

Author(s):

A. Singh ◽

M. Aggarwal ◽

T.S. Gill

Keyword(s):

Differential Equations ◽

Laser Beam ◽

Nonlinear Differential Equations ◽

Beam Width ◽

Main Beam ◽

Gaussian Laser Beam ◽

Runge Kutta Method ◽

Self Focusing ◽

Gaussian Perturbation ◽

Paraxial Ray

AbstractIn the present paper, we have investigated the growth of a Gaussian perturbation superimposed on a Gaussian laser beam. The nonlinearity we have considered is of relativistic type. We have setup the nonlinear differential equations for beam width parameter of the main beam, growth and width of the laser spike by using the WKB and paraxial ray approximation. These are coupled ordinary differential equations and therefore these are simultaneously solved numerically using the Runge Kutta method. It has been observed from the analysis that self-focusing/defocusing of the main beam and the spike determine the growth dynamic of the spike.

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Combined effect of relativistic and ponderomotive nonlinearity on self-focusing of Gaussian laser beam in a cold quantum plasma

Laser and Particle Beams ◽

10.1017/s0263034616000276 ◽

2016 ◽

Vol 34 (3) ◽

pp. 426-432 ◽

Cited By ~ 23

Author(s):

H. Kumar ◽

M. Aggarwal ◽

Richa ◽

T.S. Gill

Keyword(s):

Laser Beam ◽

Beam Width ◽

Combined Effect ◽

Quantum Plasma ◽

Gaussian Laser Beam ◽

Relativistic Case ◽

Self Focusing ◽

Ponderomotive Nonlinearity ◽

Paraxial Ray ◽

The Impact

AbstractIn the present paper, we have investigated self-focusing of Gaussian laser beam in relativistic ponderomotive (RP) cold quantum plasma. When de Broglie wavelength of charged particles is greater than or equal to the inter particle distance or equivalently the temperature is less than or equal to the Fermi temperature, quantum nature of the plasma constituents cannot be ignored. In this context, we have reported self-focusing on account of nonlinear dielectric contribution of RP plasma by taking into consideration the impact of quantum effects. We have setup the nonlinear differential equation for the beam-width parameter by paraxial ray and Wentzel Kramers Brillouin approximation and solved it numerically by the Runge Kutta Fourth order method. Our results show that additional self-focusing is achieved in case of RP cold quantum plasma than relativistic cold quantum plasma and classical relativistic case. The pinching effect offered by quantum plasma and the combined effect of relativistic and ponderomotive nonlinearity greatly enhances laser propagation up to 20 Rayleigh lengths.

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