Analysis of Surface Topography Characteristics in Electrochemical Mechanical Finishing

2010 ◽  
Vol 126-128 ◽  
pp. 658-663 ◽  
Author(s):  
Ze Fei Wei ◽  
Wen Ji Xu ◽  
Gui Bing Pang ◽  
Xu Yue Wang
Keyword(s):  
Surface Topography ◽  
Low Frequency ◽  
Surface Profile ◽  
Frequency Component ◽  
Original Surface ◽  
Auto Correlation ◽  
Before And After ◽  
Auto Correlation Function ◽  
The Mean ◽  
Quality Material

In this paper, surface topography characteristics of electrochemical mechanical finishing (ECMF) for steel was investigated. The scanning electron microscopy (SEM) was used to observe the surface topography. And the microcosmic geometry parameters were measured by Talysurf SLI2000. Compared with original surface, the surface topography characteristics of the workpiece machined by ECMF have been analyzed with altitude density function (ADF) and auto correlation function (ACF). The results show that there exist periodicity component in surface profile before and after finishing. The auto correlation curves of ECMF surface have a smaller average period compared with grinding surface. The low-frequency component and the mean ripple peak distance of original surface profile are obviously decreased. Furthermore, the ripples and peak density are increased, and the surface roughness Ra is decreased from 0.231μm to 0.023μm. The results indicate that surface quality, material ratio of the profile and wear resistance machined by ECMF are improved obviously.

Analysis of Surface Morphology Characteristics in Mechanical Finishing and Electrochemical Mechanical Finishing

2010 ◽  
Vol 44-47 ◽  
pp. 2681-2685
Author(s):  
Heng Zhou Zhen
Keyword(s):  
Surface Morphology ◽  
Low Frequency ◽  
Surface Profile ◽  
Frequency Component ◽  
Original Surface ◽  
Auto Correlation ◽  
Before And After ◽  
Auto Correlation Function ◽  
Quality Material ◽  
Morphology Characteristics

In this paper, surface morphology characteristics of mechanical finishing (MF) and electrochemical mechanical finishing (ECMF) for 45# steel was investigated. The microcosmic geometry parameters were measured by Surfcorder SE-3H. Compared with original surface, the surface morphology characteristics of the workpiece machined by MF and ECMF have been analyzed with auto correlation function (ACF). The results show that there exist periodicity component in surface profile before and after finishing. The auto correlation curves of ECMF surface have a smaller average period compared with MF surface. The low-frequency component and the mean ripple peak distance of original surface profile are obviously decreased. Furthermore, the ripples and peak density are increased, ECFM have a higher efficiency compared with MF, and the surface roughness Ra is decreased from 0.231μm to 0.032μm in 1 minute. The results indicate that surface quality, material ratio of the profile and wear resistance machined by ECMF are improved obviously.

Asperity Interactions In EHD Contacts

1978 ◽  
Vol 100 (2) ◽  
pp. 246-252 ◽  
Author(s):  
H. S. Nagaraj ◽  
D. M. Sanborn ◽  
W. O. Winer
Keyword(s):  
Frequency Domain ◽  
High Frequency ◽  
Narrow Band ◽  
Point Contact ◽  
Surface Profile ◽  
Frequency Component ◽  
Interaction Process ◽  
Contact Temperature ◽  
High Frequency Component ◽  
Before And After

Infrared temperature measurements, ferrographic analysis, and surface profilimetry were used to monitor asperity interactions in a sliding EHD point contact. The contact temperature and surface profile signals obtained both before and after a run-in period are compared in the frequency domain by means of a Fourier analyzer. The interaction of surface asperities is accompanied by the presence of a high frequency component in the infrared signal. It is also shown that only a relatively narrow band of wavelengths of the surface profile spectrum are relevant in the interaction process.

Investigation of Surface Topography at the End of Running-In Process

2013 ◽  
Vol 437 ◽  
pp. 564-567
Author(s):  
Geng Pei Zhang ◽  
Xiao Jun Liu ◽  
Wen Long Lu ◽  
Xiang Qian Jiang
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Surface Profile ◽  
Wear Process ◽  
Equilibrium Surface ◽  
Important Stage ◽  
Before And After ◽  
3D Information

Running-in process is an important stage of whole wear process. The irrelevance of surface roughness before and after running-in puzzled the running-in research. However, this conclusion was based on surface roughness derived from the 2D surface profile which does not contain 3D information, and was therefore not complete. In this paper, running-in experiments were conducted to investigate the issue. The results showed that there is no equilibrium surface topography similar with equilibrium roughness at the end of running-in process.

scholarly journals Influence of Autonomic Control on the Specific Intermittent Performance of Judo Athletes

2018 ◽  
Vol 64 (1) ◽  
pp. 99-109
Author(s):  
Bruno T. Campos ◽  
Eduardo M. Penna ◽  
João G.S. Rodrigues ◽  
Mateus Diniz ◽  
Thiago T. Mendes ◽  
...  
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Training Experience ◽  
Specific Performance ◽  
Before And After ◽  
Post Test ◽  
Judo Athletes ◽  
The Mean ◽  
Hrv Analysis ◽  
Different Levels

Abstract Judo is a high-intensity intermittent combat sport which causes cardiac adaptations both morphologically and related to the autonomic nervous system (ANS). Therefore, this study aims to verify the correlation between heart rate variability (HRV) at rest with performance in the Special Judo Fitness Test (SJFT) and whether groups with different RR values at rest show different performance in the SJFT and during post-test recovery. Sixteen judo athletes with 7.2 ± 3.9 years of training experience participated in the study. Before and after the SJFT execution HRV and lactate measurements were conducted. For HRV analysis, we used the mean interval RR, the standard deviation of the RR interval (SDNN), the root mean square of successive differences in RR intervals (RMSSD), the low frequency (LF) and high frequency (HF) in normalized and absolute units. The sample was split into two groups (low RR and high RR) to verify if this variable could differentiate between specific performance. For the SDNN, a significant and moderate correlation (r = 0.53) was found with the total number of throws and throws in the series A (r = 0.56) and B (r = 0.54) and for the RMSSD a correlation with throws during series B (r = 0.59) in the SJFT. However, the groups did not differ in performance and recovery. Therefore, HRV is related to intermittent judo performance; however, it cannot differentiate between judokas at different levels of performance.

scholarly journals The Effect of Low Frequency and Direct Current Stimulation on The Kindling Phenomenon in Rats

1981 ◽  
Vol 8 (3) ◽  
pp. 249-253 ◽  
Author(s):  
John Gaito
Keyword(s):  
Direct Current ◽  
Low Frequency ◽  
Threshold Value ◽  
Sine Wave ◽  
Second Phase ◽  
Current Group ◽  
Direct Current Stimulation ◽  
Before And After ◽  
Group A ◽  
The Mean

SUMMARY:An experiment was conducted to evaluate the effect of 1-Hz or direct current brain stimulation on kindling behavior induced by 60-Hz sine wave stimulation. The effective threshold intensity to elicit a convulsion was determined on four separate occasions with 5 days of daily trials between determinations. On each day one group of experimental rats was stimulated with 1-Hz sine wave current before and after stimulation with 60-Hz sine wave current (1-60-1 group). Another group received direct current stimulation and 60-Hz current (D-60-D group). A third group received only 60-Hz stimulation. Suppression of kindling behavior usually induced by the 60-Hz stimulation occurred with 1-Hz stimulation; the mean threshold value increased on each successive determination. Suppression was most pronounced for the direct current group; it appeared after a single trial and persisted for 32 days after the last threshold determination. In contrast, most of the rats in the 1-60-1 group had recovered from the suppression after the 32 day period of nonstimulation. A second phase of the experiment indicated that the increase in threshold values for the D-60-D group occurred after a single DC stimulation. These results are consistent with the hypothesis generated by previous research that suppression following 1-Hz stimulation is not due to tissue damage.

Relationship between Surface Roughness before and after UDR Treating

2014 ◽  
Vol 707 ◽  
pp. 90-93
Author(s):  
Li Li ◽  
Wei Li ◽  
Tao Li
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Surface Profile ◽  
Deep Rolling ◽  
Surface Residual Stress ◽  
Original Surface ◽  
Before And After

A series of samples which have different surface roughness made by 45 steel were treated by Ultrasonic Deep Rolling (UDR), influence of original surface roughness on UDR effects, such as surface profile, surface roughness and residual stress, were studied. Results shows that surface roughness was reduced substantially through UDR treating and lager the original surface roughness, larger surface roughness and surface residual stress induced by UDR treating.

Dynamics of the cardiovascular autonomic regulation during orthostatic challenge is more relaxed in women

2018 ◽  
Vol 63 (2) ◽  
pp. 139-150 ◽  
Author(s):  
Sina Reulecke ◽  
Sonia Charleston-Villalobos ◽  
Andreas Voss ◽  
Ramón González-Camarena ◽  
Jesús González-Hermosillo ◽  
...  
Keyword(s):  
Time Series ◽  
Sympathetic Activity ◽  
Low Frequency ◽  
Short Term ◽  
Auto Correlation ◽  
Complete Test ◽  
Auto Correlation Function ◽  
Head Up Tilt ◽  
Cardiovascular Autonomic Regulation ◽  
Sustained Increase

AbstractLinear dynamic analysis of cardiovascular and respiratory time series was performed in healthy subjects with respect to gender by shifted short-term segments throughout a head-up tilt (HUT) test. Beat-to-beat intervals (BBI), systolic (SYS) and diastolic (DIA) blood pressure and respiratory interval (RESP) time series were acquired in 14 men and 15 women. In time domain (TD), the descending slope of the auto-correlation function (ACF) (BBI_a31cor) was more pronounced in women than in men (p<0.05) during the HUT test and considerably steeper (p<0.01) at the end of orthostatic phase (OP). The index SYS_meanNN was slightly but significantly lower (p<0.05) in women during the complete test, while higher respiratory frequency and variability (RESP_sdNN) were found in women (p<0.05), during 10–20 min after tilt-up. In frequency domain (FD), during baseline (BL), BBI-normalized low frequency (BBI_LFN) and BBI_LF/HF were slightly but significantly lower (p<0.05), while normalized high frequency (BBI_HFN) was significantly higher in women. These differences were highly significant from the first 5 min after tilt-up (p<0.01) and highly significant (p<0.001) during 10–14 min of OP. Findings revealed that men showed instantaneously a pronounced and sustained increase in sympathetic activity to compensate orthostatism. In women, sympathetic activity was just increased slightly with delayed onset without considerably affecting sympatho-vagal balance.

The Correlation and Spectrum Research on Cylindrical Surface Lapping Machined with Abrasive Jet Finishing Restricted by Grinding Wheel

2008 ◽  
Vol 389-390 ◽  
pp. 320-325
Author(s):  
Feng Liu ◽  
Ya Dong Gong ◽  
Yu Qiao Shan ◽  
Guang Qi Cai
Keyword(s):  
Correlation Function ◽  
Cross Correlation ◽  
Low Frequency ◽  
Grinding Wheel ◽  
Small Range ◽  
Auto Correlation ◽  
Surface Contour ◽  
Power Spectral ◽  
Finishing Process ◽  
Auto Correlation Function

With the correlation in stochastic process applied to the experimental results, the surface during grinding and further lapping with abrasive jet finishing (AJF) restricted by grinding wheel was investigated with respect to auto correlation function (ACF) , cross correlation function (CCF) and power spectral density (PSD) analysis. The results indicated that AJF made the surface contour formed periodicity in a small range and removed fluctuation of the surface contour in low frequency greatly. The average spacing of the surface contour decreased and the machined surfaces changed from continuous parallel micro-groove and plough to randomly distributed discontinuous micro-pit with the increase of machining circles. The surface texture became fine and surface roughness was obviously improved. Furthermore, the isotropy surface and uniformity veins both parallel and perpendicular machining direction was attained by the finishing process to improve greatly the wearable capability of the workpiece.

Effect of hot arm and foot bath on heart rate variability and blood pressure in healthy volunteers

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Samruddhi Chintaman Vyas ◽  
A. Mooventhan ◽  
N. K. Manjunath
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Healthy Volunteers ◽  
High Frequency ◽  
Low Frequency ◽  
Healthy Male ◽  
Before And After ◽  
Instantaneous Heart Rate ◽  
The Mean

AbstractBackgroundThough hot arm and foot bath (HAFB) is widely used, a precise physiological response is not reported. Hence, the present study was conducted to evaluate the effect of HAFB on heart rate variability (HRV) and blood pressure (BP) in healthy volunteers.Materials and MethodsSixteen healthy male volunteers’ aged 23.81 ± 5.27 (mean ± standard deviation) years were recruited. All the subjects underwent only one session of HAFB (104-degree Fahrenheit) for the duration of 20 min. Assessments such as Electrocardiography and BP were taken before and after the intervention.ResultsResults of this study showed a significant reduction in systolic-BP (SBP), diastolic-BP (DBP), mean arterial pressure (MAP), the mean of the intervals between adjacent QRS complexes or the instantaneous heart rate (RR interval), the number of interval differences of successive NN intervals greater than 50 ms (NN50), the proportion derived by dividing NN50 by the total number of NN intervals (pNN50), and high frequency (HF) band of HRV along with a significant increase in heart rate (HR), low-frequency (LF) band of HRV and LF/HF ratio compared to its baseline.ConclusionsResults of this study suggest that 20 min of HAFB produce a significant increase in HR and a significant reduction in SBP, DBP, and MAP while producing parasympathetic withdrawal.

scholarly journals Interactions between Typhoon Megi (2010) and a Low-Frequency Monsoon Gyre

2015 ◽  
Vol 72 (7) ◽  
pp. 2682-2702 ◽  
Author(s):  
Mingyu Bi ◽  
Tim Li ◽  
Melinda Peng ◽  
Xinyong Shen
Keyword(s):  
Low Frequency ◽  
Frequency Component ◽  
The Philippines ◽  
Sharp Change ◽  
Budget Analysis ◽  
Before And After ◽  
Arw Model ◽  
Monsoon Gyre ◽  
Scale Motion ◽  
Vorticity Tendency

The ARW Model is used to investigate the sharp northward turn of Super Typhoon Megi (2010) after it moved westward and crossed the Philippines. The NCEP analyzed fields during this period are separated into a slowly varying background-flow component, a 10–60-day low-frequency component representing the monsoon gyre, and a 10-day high-pass-filtered component representing Megi and other synoptic-scale motion. It appears that the low-frequency (10–60 day) monsoon gyre interacted with Megi and affected its track. To investigate the effect of the low-frequency mode on Megi, numerical experiments were designed. In the control experiment, the total fields of the analysis are retained in the initial and boundary conditions, and the model is able to simulate Megi’s sharp northward turn. In the second experiment, the 10–60-day monsoon gyre mode is removed from the initial and lateral boundary fields, and Megi moves westward and slightly northwestward without turning north. Tracks of the relative positions between the Megi and the monsoon gyre centers suggest that a Fujiwhara effect may exist between the monsoon gyre and Megi. The northward turning of both Megi and the monsoon gyre occurred when the two centers were close to each other and the beta drift was enhanced. A vorticity budget analysis was conducted. It is noted that the Megi moves toward the maximum wavenumber-1 vorticity tendency. The sharp change of the maximum vorticity tendency direction before and after the track turning point is primarily attributed to the change of the horizontal vorticity advection. A further diagnosis shows that the steering of the vertically integrated low-frequency flow is crucial for the change of the horizontal advection tendency.

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