scholarly journals Analysis of the Noise Reduction Characteristics of a Diffuser with Fizeau Interferometry

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Hongjun Wang ◽  
Xueliang Zhu ◽  
Bingcai Liu ◽  
Ailing Tian
Keyword(s):  
Surface Roughness ◽  
Noise Reduction ◽  
Rotation Speed ◽  
Effective Range ◽  
Coherent Noise ◽  
Fringe Contrast ◽  
Effective Roughness ◽  
Reduction Characteristics ◽  
The Relationship ◽  
Interference Image

To solve the coherent noise problem of an interference image, the method of a rotating diffuser was adopted to change the coherence of a beam to reduce the noise of the interference system. The relationship between the speed of the diffuser and the signal-to-noise ratio (SNR) of the fringe contrast system was simulated to obtain the diffuser control parameters needed for the best interference fringe state. The fringe contrast of each image and the SNR of the system were analyzed. The results showed that the increased speed of the diffuser reduced the contrast of the interference image to a certain extent, but the increased speed also effectively improved the SNR and facilitated the subsequent interference image processing. Due to the coherent noise in the interferometric system, the method of the rotated diffuser reduced the coherence of the light beam to suppress the noise of the interference image. By analyzing the coherent noise reduction characteristics of the rotated diffuser with different surface roughnesses, the relationship between the surface roughness and the noise contrast for different rotation speeds was simulated, and the effective roughness range with the noise reduction effect was selected. A noise reduction system was built based on Fizeau interference, and the noise contrast of the interference image was collected and calculated. The effective range of σh/λ was 0.2–0.5 when the rotation speed was 10 r/s, while the effective range of σh/λ was 0.4–0.6 when the rotation speed was 100 r/s. The experimental results showed that the surface roughness and wavelength ratio σh/λ of the rotated diffuser increased when the noise contrast tended toward 1, but the effective range of the surface roughness decreased with the increase of the rotational speed of the diffuser.

Possible examinations of stone machining focused on the relationship between technological parameters and surface quality

2013 ◽  
Vol 4 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Zs. Kun ◽  
I. G. Gyurika
Keyword(s):  
Surface Roughness ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Theoretical Background ◽  
Motion Path ◽  
Depth Of Cut ◽  
Manufacturing Cost ◽  
Technological Parameters ◽  
The Relationship ◽  
Manufacturing Time

Abstract The stone products with different sizes, geometries and materials — like machine tool's bench, measuring machine's board or sculptures, floor tiles — can be produced automatically while the manufacturing engineer uses objective function similar to metal cutting. This function can minimise the manufacturing time or the manufacturing cost, in other cases it can maximise of the tool's life. To use several functions, manufacturing engineers need an overall theoretical background knowledge, which can give useful information about the choosing of technological parameters (e.g. feed rate, depth of cut, or cutting speed), the choosing of applicable tools or especially the choosing of the optimum motion path. A similarly important customer's requirement is the appropriate surface roughness of the machined (cut, sawn or milled) stone product. This paper's first part is about a five-month-long literature review, which summarizes in short the studies (researches and results) considered the most important by the authors. These works are about the investigation of the surface roughness of stone products in stone machining. In the second part of this paper the authors try to determine research possibilities and trends, which can help to specify the relation between the surface roughness and technological parameters. Most of the suggestions of this paper are about stone milling, which is the least investigated machining method in the world.

Pulse-Width Modulated Amplifier for DC Servo System and Its Matlab Simulation

2015 ◽  
Vol 9 (1) ◽  
pp. 625-631
Author(s):  
Ma Xiaocheng ◽  
Zhang Haotian ◽  
Cheng Yiqing ◽  
Zhu Lina ◽  
Wu Dan
Keyword(s):  
Mathematical Model ◽  
Transfer Function ◽  
Input Signal ◽  
Pulse Width ◽  
Rotation Speed ◽  
Servo Motor ◽  
Matlab Simulation ◽  
Pulse Width Modulated ◽  
Signal Changes ◽  
The Relationship

This paper introduces a mathematical model for Pulse-Width Modulated Amplifier for DC Servo Motor. The relationship between pulse-width modulated (PWM) signal and reference rotation speed is specified, and a general model of motor represented by transfer function is also put forward. When the input signal changes, the rotation speed of the servo motor will change accordingly. By changing zeros and poles, transient performance of this system is discussed in detail, and optimal ranges of the parameters is recommended at the end of discussion.

scholarly journals Coherent noise reduction in digital holographic phase contrast microscopy by slightly shifting object

2011 ◽  
Vol 19 (5) ◽  
pp. 3862 ◽  
Author(s):  
Feng Pan ◽  
Wen Xiao ◽  
Shuo Liu ◽  
FanJing Wang ◽  
Lu Rong ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Phase Contrast ◽  
Phase Contrast Microscopy ◽  
Coherent Noise ◽  
Contrast Microscopy

scholarly journals Sensitivity of C-Band SAR Polarimetric Variables to the Directionality of Surface Roughness Parameters

2021 ◽  
Vol 13 (11) ◽  
pp. 2210
Author(s):  
Zohreh Alijani ◽  
John Lindsay ◽  
Melanie Chabot ◽  
Tracy Rowlandson ◽  
Aaron Berg
Keyword(s):  
Surface Roughness ◽  
Soil Moisture ◽  
Laser Scanner ◽  
Careful Attention ◽  
Roughness Parameters ◽  
Retrieval Models ◽  
Surface Roughness Parameters ◽  
The Look ◽  
The Relationship ◽  
Roughness Measurements

Surface roughness is an important factor in many soil moisture retrieval models. Therefore, any mischaracterization of surface roughness parameters (root mean square height, RMSH, and correlation length, ʅ) may result in unreliable predictions and soil moisture estimations. In many environments, but particularly in agricultural settings, surface roughness parameters may show different behaviours with respect to the orientation or azimuth. Consequently, the relationship between SAR polarimetric variables and surface roughness parameters may vary depending on measurement orientation. Generally, roughness obtained for many SAR-based studies is estimated using pin profilers that may, or may not, be collected with careful attention to orientation to the satellite look angle. In this study, we characterized surface roughness parameters in multi-azimuth mode using a terrestrial laser scanner (TLS). We characterized the surface roughness parameters in different orientations and then examined the sensitivity between polarimetric variables and surface roughness parameters; further, we compared these results to roughness profiles obtained using traditional pin profilers. The results showed that the polarimetric variables were more sensitive to the surface roughness parameters at higher incidence angles (θ). Moreover, when surface roughness measurements were conducted at the look angle of RADARSAT-2, more significant correlations were observed between polarimetric variables and surface roughness parameters. Our results also indicated that TLS can represent more reliable results than pin profiler in the measurement of the surface roughness parameters.

Study of the Relationship between Tool Wear and Surface Finish in Turning with Carbide Tool

2014 ◽  
Vol 902 ◽  
pp. 95-100 ◽  
Author(s):  
Heraldo J. Amorim ◽  
Augusto O. Kunrath Neto
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Surface Finish ◽  
Cutting Speed ◽  
Single Equation ◽  
Carbon Steels ◽  
High Dispersion ◽  
Exponential Relationship ◽  
Processed Material ◽  
The Relationship

The aim of this work is to analyze the tool wear effects on surface finish of machined components. Long-term machinability tests were performed for ASTM 1040 and 1045 carbon steels with carbide tools, in which tool wear and surface roughness were periodically evaluated. Surface finish was analyzed as a function of processed material and cutting speed with new machining tool, and a significant influence was found for cutting speed at a confidence interval of 10%. When evaluated as a function of time and tool wear, surface roughness showed an exponential relationship with both variables. However, a high dispersion occurs close to the end of tool life, especially for AISI 1040 steel. Weak influence of cutting speed (for the range of speeds tested) was observed on the relationship between tool wear and surface finish, indicating that a single equation can describe its behavior for all studied conditions. The relationship between the surface roughness and the cutting time was found to be stronger for the ABNT 1040 steel.

scholarly journals Experimental Study on Machinability of Zr-Based Bulk Metallic Glass during Micro Milling

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 86 ◽  
Author(s):  
Tao Wang ◽  
Xiaoyu Wu ◽  
Guoqing Zhang ◽  
Bin Xu ◽  
Yinghua Chen ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Feed Rate ◽  
Rotation Speed ◽  
Amorphous Structure ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Milling Force ◽  
Coated Cemented Carbide

The micro machinability of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass (BMG) was investigated by micro milling with coated cemented carbide tools. The corresponding micro milling tests on Al6061 were conducted for comparison. The results showed that the tool was still in stable wear stage after milling 300 mm, and the surface roughness Ra could be maintained around 0.06 μm. The tool experienced only slight chipping and rubbing wear after milling the BMG, while a built-up edge and the coating peeling off occurred severely when milling Al6061. The influence of rotation speed on surface roughness was insignificant, while surface roughness decreased with the reduction of feed rate, and then increased dramatically when the feed rate was below 2 μm/tooth. The surface roughness increased gradually with the axial depth of cut (DOC). Milling force decreased slightly with the increase in rotation speed, while it increased with the increase in axial DOC, and the size effect on milling force occurred when the feed rate decreased below 1 μm/tooth. The results of X-ray diffraction (XRD) showed that all milled surfaces were still dominated by an amorphous structure. This study could pave a solid foundation for structural and functional applications.

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