The Experts below are selected from a list of 27033 Experts worldwide ranked by ideXlab platform
Simon C Lea - One of the best experts on this subject based on the ideXlab platform.
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the effect of wear on ultrasonic scaler tip Displacement Amplitude
Journal of Clinical Periodontology, 2006Co-Authors: Simon C Lea, Gabriel Landini, Damien A WalmsleyAbstract:Aim: During clinical usage, scaler tips may become worn and reduced in length. It is unknown what effect wear has on the magnitude of scaler tip vibrations when they are utilized under typical clinical loads. The aim of this investigation was to assess the effect of simulated wear on ultrasonic scaler tip Displacement Amplitude, using a scanning laser vibrometer. Materials and Methods: A Cavitron SPS (Dentsply) ultrasonic generator and three scaler insert designs (FSI-100, FSI-1000 and FSI-SLI-10S) were selected for the investigation. Tip vibration Displacement Amplitude was assessed unloaded and then contacting against tooth surfaces with loads of 0.5 and 1.0 N. Tips were then ground down by 1 mm and then 2 mm and scans were repeated. Results: For all tips, load and length were found to be significant variables (p<0.0001). The scaler tips showed a fall in Displacement Amplitude with a reduction in tip length. However, all scaler tips showed variability in the amount oscillation that occurred. This was most pronounced with FSI-SLI-10S. Conclusions: This investigation demonstrated that tip wear could affect the performance of dental ultrasonic scaler inserts by reducing their vibration Displacement Amplitude. Clinicians should be aware of this variability, which may be significant enough to affect clinical procedures.
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The effect of wear on ultrasonic scaler tip Displacement Amplitude
Journal of clinical periodontology, 2006Co-Authors: Simon C Lea, Gabriel Landini, A. Damien WalmsleyAbstract:Aim: During clinical usage, scaler tips may become worn and reduced in length. It is unknown what effect wear has on the magnitude of scaler tip vibrations when they are utilized under typical clinical loads. The aim of this investigation was to assess the effect of simulated wear on ultrasonic scaler tip Displacement Amplitude, using a scanning laser vibrometer. Materials and Methods: A Cavitron SPS (Dentsply) ultrasonic generator and three scaler insert designs (FSI-100, FSI-1000 and FSI-SLI-10S) were selected for the investigation. Tip vibration Displacement Amplitude was assessed unloaded and then contacting against tooth surfaces with loads of 0.5 and 1.0 N. Tips were then ground down by 1 mm and then 2 mm and scans were repeated. Results: For all tips, load and length were found to be significant variables (p
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A new insight into the oscillation characteristics of endosonic files used in dentistry.
Physics in medicine and biology, 2004Co-Authors: Simon C Lea, A D Walmsley, Philip J. Lumley, Gabriel LandiniAbstract:The aim of this study was to assess the oscillation characteristics of unconstrained endosonic files using a scanning laser vibrometer (SLV). Factors investigated included file vibration frequency and node/antinode location as well as the variation in file Displacement Amplitude due to increasing generator power setting. A 30 kHz Mini Piezon generator (Electro-Medical Systems, Switzerland) was used in conjunction with a #15 and #35 K-file. Each file was fixed in position with the long axis of the file perpendicular to the SLV camera head. The laser from the SLV was scanned over the length of the oscillating file for generator power settings 1 to 5 (minimum to half power). Measurements were repeated ten times. The fundamental vibration frequency for both files was 27.50 kHz. Scans of each file showed the positions of nodes/anti-nodes along the file length. The #15 file demonstrated no significant variation in its mean maximum Displacement Amplitude with increasing generator power, except at power setting 5, where a decrease in Displacement Amplitude was observed. The #35 file showed a general increase in mean maximum Displacement Amplitude with increasing power setting, except at power setting 4 where a 65% decrease in Displacement Amplitude occurred. In conclusion, scanning laser vibrometry is an effective method for assessing endosonic file vibration characteristics. The SLV was able to demonstrate that (unloaded) file vibration Displacement Amplitude does not increase linearly with increasing generator power. Further work is being performed on a greater variety of files and generators. Vibration characteristics of files under various loads and varying degrees of constraint should also be investigated.
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Displacement Amplitude of ultrasonic scaler inserts
Journal of Clinical Periodontology, 2003Co-Authors: Simon C Lea, Gabriel Landini, A D WalmsleyAbstract:OBJECTIVES Scanning laser vibrometry is a noninvasive method of measuring the velocity, Displacement Amplitude and oscillation frequency of vibrating objects. The purpose of this study was to assess, using a scanning laser vibrometer (SLV), the performance of different designs of commercially available ultrasonic scaler generators by measuring the oscillatory characteristics of various scaler tips. METHODS Four ultrasonic generators were tested (Cavitron SPS and Cavitron Select (Dentsply, York, PA, USA) and Piezon Master 400 and Mini Piezon (Electro-Medical Systems, Switzerland)) with various designs of scaler tip. The tips were positioned with their anterior surface perpendicular to the direction of the laser. A graduated scale, placed over the manufacturer's power dial, enabled incremental power setting selection. For each power setting, the laser beam from the SLV was scanned over the surface of the oscillating tip. RESULTS The ranges of longitudinal Displacement Amplitudes (in micrometres) were as follows: Mini Piezon (P-tip): 12.90+/-1.44 to 44.03+/-7.80; Piezon Master 400 (P-tip): 16.02+/-2.66 to 35.85+/-5.29; Cavitron SPS (TFI-10 tip): 7.81+/-0.51 to 29.70+/-1.12; Cavitron Select (TFI-10 tip): 13.13+/-1.44 to 33.77+/-4.27; Cavitron SPS (TFI-3 tip): 5.50+/-0.46 to 31.35+/-3.62. CONCLUSIONS This study shows that there are differences between commercially available generators and that tip movement varies between tips of the same style as well as between the generator and tip design. Users of ultrasonic scalers should be made aware of this inherent variability that may influence clinical procedures.
Gabriel Landini - One of the best experts on this subject based on the ideXlab platform.
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the effect of wear on ultrasonic scaler tip Displacement Amplitude
Journal of Clinical Periodontology, 2006Co-Authors: Simon C Lea, Gabriel Landini, Damien A WalmsleyAbstract:Aim: During clinical usage, scaler tips may become worn and reduced in length. It is unknown what effect wear has on the magnitude of scaler tip vibrations when they are utilized under typical clinical loads. The aim of this investigation was to assess the effect of simulated wear on ultrasonic scaler tip Displacement Amplitude, using a scanning laser vibrometer. Materials and Methods: A Cavitron SPS (Dentsply) ultrasonic generator and three scaler insert designs (FSI-100, FSI-1000 and FSI-SLI-10S) were selected for the investigation. Tip vibration Displacement Amplitude was assessed unloaded and then contacting against tooth surfaces with loads of 0.5 and 1.0 N. Tips were then ground down by 1 mm and then 2 mm and scans were repeated. Results: For all tips, load and length were found to be significant variables (p<0.0001). The scaler tips showed a fall in Displacement Amplitude with a reduction in tip length. However, all scaler tips showed variability in the amount oscillation that occurred. This was most pronounced with FSI-SLI-10S. Conclusions: This investigation demonstrated that tip wear could affect the performance of dental ultrasonic scaler inserts by reducing their vibration Displacement Amplitude. Clinicians should be aware of this variability, which may be significant enough to affect clinical procedures.
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The effect of wear on ultrasonic scaler tip Displacement Amplitude
Journal of clinical periodontology, 2006Co-Authors: Simon C Lea, Gabriel Landini, A. Damien WalmsleyAbstract:Aim: During clinical usage, scaler tips may become worn and reduced in length. It is unknown what effect wear has on the magnitude of scaler tip vibrations when they are utilized under typical clinical loads. The aim of this investigation was to assess the effect of simulated wear on ultrasonic scaler tip Displacement Amplitude, using a scanning laser vibrometer. Materials and Methods: A Cavitron SPS (Dentsply) ultrasonic generator and three scaler insert designs (FSI-100, FSI-1000 and FSI-SLI-10S) were selected for the investigation. Tip vibration Displacement Amplitude was assessed unloaded and then contacting against tooth surfaces with loads of 0.5 and 1.0 N. Tips were then ground down by 1 mm and then 2 mm and scans were repeated. Results: For all tips, load and length were found to be significant variables (p
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A new insight into the oscillation characteristics of endosonic files used in dentistry.
Physics in medicine and biology, 2004Co-Authors: Simon C Lea, A D Walmsley, Philip J. Lumley, Gabriel LandiniAbstract:The aim of this study was to assess the oscillation characteristics of unconstrained endosonic files using a scanning laser vibrometer (SLV). Factors investigated included file vibration frequency and node/antinode location as well as the variation in file Displacement Amplitude due to increasing generator power setting. A 30 kHz Mini Piezon generator (Electro-Medical Systems, Switzerland) was used in conjunction with a #15 and #35 K-file. Each file was fixed in position with the long axis of the file perpendicular to the SLV camera head. The laser from the SLV was scanned over the length of the oscillating file for generator power settings 1 to 5 (minimum to half power). Measurements were repeated ten times. The fundamental vibration frequency for both files was 27.50 kHz. Scans of each file showed the positions of nodes/anti-nodes along the file length. The #15 file demonstrated no significant variation in its mean maximum Displacement Amplitude with increasing generator power, except at power setting 5, where a decrease in Displacement Amplitude was observed. The #35 file showed a general increase in mean maximum Displacement Amplitude with increasing power setting, except at power setting 4 where a 65% decrease in Displacement Amplitude occurred. In conclusion, scanning laser vibrometry is an effective method for assessing endosonic file vibration characteristics. The SLV was able to demonstrate that (unloaded) file vibration Displacement Amplitude does not increase linearly with increasing generator power. Further work is being performed on a greater variety of files and generators. Vibration characteristics of files under various loads and varying degrees of constraint should also be investigated.
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Displacement Amplitude of ultrasonic scaler inserts
Journal of Clinical Periodontology, 2003Co-Authors: Simon C Lea, Gabriel Landini, A D WalmsleyAbstract:OBJECTIVES Scanning laser vibrometry is a noninvasive method of measuring the velocity, Displacement Amplitude and oscillation frequency of vibrating objects. The purpose of this study was to assess, using a scanning laser vibrometer (SLV), the performance of different designs of commercially available ultrasonic scaler generators by measuring the oscillatory characteristics of various scaler tips. METHODS Four ultrasonic generators were tested (Cavitron SPS and Cavitron Select (Dentsply, York, PA, USA) and Piezon Master 400 and Mini Piezon (Electro-Medical Systems, Switzerland)) with various designs of scaler tip. The tips were positioned with their anterior surface perpendicular to the direction of the laser. A graduated scale, placed over the manufacturer's power dial, enabled incremental power setting selection. For each power setting, the laser beam from the SLV was scanned over the surface of the oscillating tip. RESULTS The ranges of longitudinal Displacement Amplitudes (in micrometres) were as follows: Mini Piezon (P-tip): 12.90+/-1.44 to 44.03+/-7.80; Piezon Master 400 (P-tip): 16.02+/-2.66 to 35.85+/-5.29; Cavitron SPS (TFI-10 tip): 7.81+/-0.51 to 29.70+/-1.12; Cavitron Select (TFI-10 tip): 13.13+/-1.44 to 33.77+/-4.27; Cavitron SPS (TFI-3 tip): 5.50+/-0.46 to 31.35+/-3.62. CONCLUSIONS This study shows that there are differences between commercially available generators and that tip movement varies between tips of the same style as well as between the generator and tip design. Users of ultrasonic scalers should be made aware of this inherent variability that may influence clinical procedures.
Damien A Walmsley - One of the best experts on this subject based on the ideXlab platform.
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the effect of wear on ultrasonic scaler tip Displacement Amplitude
Journal of Clinical Periodontology, 2006Co-Authors: Simon C Lea, Gabriel Landini, Damien A WalmsleyAbstract:Aim: During clinical usage, scaler tips may become worn and reduced in length. It is unknown what effect wear has on the magnitude of scaler tip vibrations when they are utilized under typical clinical loads. The aim of this investigation was to assess the effect of simulated wear on ultrasonic scaler tip Displacement Amplitude, using a scanning laser vibrometer. Materials and Methods: A Cavitron SPS (Dentsply) ultrasonic generator and three scaler insert designs (FSI-100, FSI-1000 and FSI-SLI-10S) were selected for the investigation. Tip vibration Displacement Amplitude was assessed unloaded and then contacting against tooth surfaces with loads of 0.5 and 1.0 N. Tips were then ground down by 1 mm and then 2 mm and scans were repeated. Results: For all tips, load and length were found to be significant variables (p<0.0001). The scaler tips showed a fall in Displacement Amplitude with a reduction in tip length. However, all scaler tips showed variability in the amount oscillation that occurred. This was most pronounced with FSI-SLI-10S. Conclusions: This investigation demonstrated that tip wear could affect the performance of dental ultrasonic scaler inserts by reducing their vibration Displacement Amplitude. Clinicians should be aware of this variability, which may be significant enough to affect clinical procedures.
A. Damien Walmsley - One of the best experts on this subject based on the ideXlab platform.
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The effect of wear on ultrasonic scaler tip Displacement Amplitude
Journal of clinical periodontology, 2006Co-Authors: Simon C Lea, Gabriel Landini, A. Damien WalmsleyAbstract:Aim: During clinical usage, scaler tips may become worn and reduced in length. It is unknown what effect wear has on the magnitude of scaler tip vibrations when they are utilized under typical clinical loads. The aim of this investigation was to assess the effect of simulated wear on ultrasonic scaler tip Displacement Amplitude, using a scanning laser vibrometer. Materials and Methods: A Cavitron SPS (Dentsply) ultrasonic generator and three scaler insert designs (FSI-100, FSI-1000 and FSI-SLI-10S) were selected for the investigation. Tip vibration Displacement Amplitude was assessed unloaded and then contacting against tooth surfaces with loads of 0.5 and 1.0 N. Tips were then ground down by 1 mm and then 2 mm and scans were repeated. Results: For all tips, load and length were found to be significant variables (p
Minhao Zhu - One of the best experts on this subject based on the ideXlab platform.
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Influence of Wear Test Parameters on the Electrical Contact Performance of Brass Alloy/Copper Contactors Under Fretting Wear
Journal of Materials Engineering and Performance, 2019Co-Authors: Xinlong Liu, Shanbang Liu, Songbo Wu, Zhenbing Cai, Minhao ZhuAbstract:Fretting of mated electronic connectors may be due to extreme increase in contact resistance. We present a detailed analysis of contact resistance by fretting experiments using brass alloys/copper contact pairs. The relationship between wear mechanisms and contact resistance was determined. The influence of fundamental factors such as normal load, Displacement Amplitude, and current on contact resistance change was also evaluated. It was found out that Displacement Amplitude, normal load, and current are important parameters for infinite lifetime or stable electrical resistance during fretting condition. Influence of Displacement Amplitude on the electrical contact performance might be affected by wear debris in the contact area. Electric contact performance could be improved by increasing the power current, which could break down the thick oxide film formed. The predicted working lifetime and reliability requirements of the connector were determined to optimize and extend the service life under the working condition.
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fretting wear behavior of acrylonitrile butadiene rubber nbr for mechanical seal applications
Tribology International, 2016Co-Authors: Mingxue Shen, Xudong Peng, Xiangkai Meng, Jinpeng Zheng, Minhao ZhuAbstract:Abstract The fretting wear behavior of acrylonitrile–butadiene rubber (NBR) was studied. The variation of fretting running behavior, coefficient of friction (COF) and wear mechanisms as a function of Displacement Amplitude and load were discussed in detail. Results showed that the sticky layers on the worn surface played an important role in fretting wear. Various damage characteristics could be exhibited in different fretting running regimes, and the fretting characteristics were strongly dependent on the Displacement Amplitude. However, the normal load had little effect on the evolution of the fretting wear. The results of X-ray photoelectron spectroscopy (XPS) revealed that no thermal degradation occurred in rubber during fretting tests.
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tribological behavior of polymethyl methacrylate against different counter bodies induced by torsional fretting wear
Wear, 2011Co-Authors: Zhenbing Cai, Minhao Zhu, Shanshan Gao, Xiuzhou Lin, Juan LiuAbstract:Abstract A torsional wear and friction simulator with a ball on flat polymer was developed to analyze the tribological behavior of hip joints. Wear tests of polymethyl methacrylate (PMMA) against GCr15 (AISI 52100) steel and PMMA molecules (both with diameters of 40 mm) were conducted. Based on the analysis of frictional kinetics behaviors, and observations of three-dimensional (3D) profiles and SEM morphologies, the damage characteristics of PMMA were discussed in detail. With the increases of angular Displacement Amplitude, three types of torque/angular Displacement Amplitude ( T – θ ) curves (i.e., linear, parallelogram, and elliptical loops) were observed during the process of torsional fretting wear. In each of these loops, PMMA ran in a partial slip regime (PSR), mixed slip regime (MSR), and gross slip regime (SR), respectively. Compared to the PMMA/PMMA (P/P) counter-pairs, the boundary of the fretting regime of PMMA/GCr15 (P/G) counter-pairs shifted toward the direction of lower angular Displacement Amplitudes. The wear mechanisms of P/G counter-pairs included fatigue wear, oxidative wear, and adhesive wear; however, only abrasive wear was found for the P/P counter-pairs.
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An Experimental Study on the Rotational Fretting Wear Behavior of LZ50 Steel
Advanced Tribology, 2009Co-Authors: Z. J. Liao, Minhao Zhu, Zhou ZhongrongAbstract:Rotational fretting tests in a configuration of ball-on-flat have been successfully realized by developing a new fretting device based on an ultra-low-speed reciprocating rotational driver. The rotational fretting tests of LZ50 steel flats against 52100 steel balls were performed under different testing parameters, i.e. the angular Displacement Amplitudes of 0.25° to 1° and the normal loads of 5 N to 20 N. The frictional kinetics of rotational fretting and the characteristic of wear damage for LZ50 steel were discussed in detail. The results showed that the rotational fretting behavior of the LZ50 was strongly dependent upon the angular Displacement Amplitude and normal load. Friction force-angular Displacement (F t -θ) curves can be used to characterize the rotational fretting running behavior, which exhibited three basic types of the parallelogram, elliptical and linear cycles by varying the angular Displacement Amplitudes or normal loads. Under the condition of the angular Displacement Amplitude of 0.25° and the normal load of 10 N, the rotational fretting run in the regime of partial slip, which corresponding elastic deformation coordination at the contact interface. With the increase of the angular Displacement Amplitude and the decrease of normal load, the fretting running state transferred from the partial slip to the gross slip. The micro-examinations indicated that the plastic deformation, abrasive wear, oxidative wear and delamination were the main damage mechanism for LZ50 steel under the gross slip conditions. A special phenomenon which different from that observed in the tests of the normal reciprocating fretting (tangential fretting), i.e. wear debris generated was accumulated in the centre zone of the wear scar under the condition of gross slip, was observed in this paper.
