scholarly journals Experimental study on the factors affecting torque of beam-type implant torque wrenches

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hiroki Shiba ◽  
Yuji Sato ◽  
Junichi Furuya ◽  
Tokiko Osawa ◽  
Akio Isobe ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Leading Edge ◽  
Beam Width ◽  
Factors Affecting ◽  
Tightening Force ◽  
Torque Wrench ◽  
Screw Breakage ◽  
Beam Type ◽  
Accuracy And Repeatability ◽  
Excellent Accuracy

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.

scholarly journals Factors Affecting Torque of Beam Type Implant Torque Wrench 

2021 ◽  
Author(s):  
Yuji Sato ◽  
Junichi Furuya ◽  
Tokiko Osawa ◽  
Akio Isobe ◽  
Myu Hayashi ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Beam Width ◽  
Factors Affecting ◽  
Tightening Torque ◽  
Torque Wrench ◽  
Screw Breakage ◽  
Beam Type ◽  
The Difference ◽  
Torque Values ◽  
Accuracy And Repeatability

Abstract Background: Screw breakage and loosening are the most common mechanical complications in implant treatment. One of the causes is the excess or deficiency of the screw tightening torque; thus, the use of a torque wrench is a prerequisite for achieving an accurate tightening torque. Therefore, we focused on the beam-type torque wrenches, which are the main type, to clarify the factors affecting this torque.Results: The torque values of the beam-type torque wrenches for the eight manufacturers were measured using a torque gauge. For investigating the influence of the location of the beam placed on the scale, the measurement was performed with the scale aligned with the upper edge, center, and lower edge of the beam. 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 value of each manufacturer's screws five times clockwise. The average measured torque, standard deviation, bias, and coefficient of variation were calculated and compared. Equipment from six manufacturers demonstrated the best accuracy for measurements at the center of the beam (bias within ± 4%). For measurements at 90°, equipment from five manufacturers displayed the highest accuracy (bias within ± 7%), and seven showed the highest repeatability (coefficient of variation 2% or less).Conclusion: It was recommended that the center of the beam should be aligned with the scale and read from 90°, while tightening the torque wrench. The accuracy and repeatability differed according to the manufacturer, scale width, scale line width, and beam width, while the distance between scale and beam center was related to accuracy and repeatability. Based on these results, it was suggested that a torque wrench must be selected after grasping the difference depending on the structure of the model to be used.

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

2014 ◽  
Vol 41 (2) ◽  
pp. 0208002 ◽  
Author(s):  
王艳萍 Wang Yanping ◽  
王茜蒨 Wang Qianqian ◽  
马冲 Ma Chong
Keyword(s):  
Laser Beam ◽  
Ccd Camera ◽  
Beam Width ◽  
Factors Affecting

Collaborative Study of Methods for the Analysis and Control of AG-Chlordane and Its Formulations

1973 ◽  
Vol 56 (3) ◽  
pp. 591-595
Author(s):  
Marshall A Malina
Keyword(s):  
Coefficient Of Variation ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Assay Method ◽  
Good Precision ◽  
Accuracy And Precision ◽  
Infrared Method ◽  
Gas Chromatographic Method ◽  
And Control ◽  
Excellent Accuracy

Abstract Four methods for the analysis of AG-chlordane and its formulations were submitted to a collaborative study. Fifteen laboratories, including 5 CIPAC laboratories, participated in this study. The infrared method for the analysis of the content of the 2 chlordane isomers was precise, with a coefficient of variation of 0.015. The gas chromatographic method for the analysis of the heptachlor content also yielded good precision with a standard deviation of 0.16. The infrared assay method for granular formulations exhibited excellent accuracy and precision, with a coefficient of variation of 0.067 and an error of only +0.25% relative. The gas chromatographic assay method for emulsifiable concentrates exhibited poor accuracy and precision and was found unacceptable. The first 3 methods have been adopted as official first action.

ESTIMATION OF UNCERTAINTY IN MEASUREMENT OF DOSE EQUIVALENT AT LABORATORY LEVEL USING CASO4 :Dy-BASED TLD BADGE SYSTEM IN INDIA

2019 ◽  
Vol 188 (2) ◽  
pp. 135-147 ◽  
Author(s):  
S M Pradhan ◽  
D Datta ◽  
Munir S Pathan ◽  
Kshama Srivastava ◽  
T Palani Selvam
Keyword(s):  
Coefficient Of Variation ◽  
Whole Body ◽  
Dose Equivalent ◽  
Radiation Quality ◽  
Variance Model ◽  
Factors Affecting ◽  
Uncertainty In Measurement ◽  
Photon Dose ◽  
Combined Uncertainty ◽  
Quality Coefficient

Abstract The objective of this paper is to estimate the combined uncertainty in the measurement of dose equivalent at laboratory level using CaSO4:Dy-based thermoluminescent dosemeter badge system by including variations in the components of the system. The variability of performance of the system is analysed using random effects one way analysis of variance model. The model enables estimation of the overall variance of the performance of the sampled population. The population in the study comprises all possible indicated dose equivalents on irradiation of dosemeters to a specific dose equivalent and radiation quality. Coefficient of variation and combined uncertainty at 95% level of confidence in the measurement of Hp(10) due to S-Cs radiation quality are found to be 6.6 and 14.3%, respectively, at the dose level of 5.31 mSv. The above parameters in the measurement of in-use quantity, i.e. whole body dose or photon dose equivalent are found to be 7.4 and 16.4%, respectively. The performance of the monitoring system on relative response has been observed to be satisfactory. Various factors affecting the variability of performance of the system are identified for further improvement in coefficient of variation.

INVESTIGATION OF TORQUE GENERATION CAPABILITY OF MIXED FLOW TURBINE UNDER STEADY STATE CONDITIONS

2017 ◽  
Vol 79 (7-3) ◽  
Author(s):  
M. A. S. Izaiddin ◽  
A. F. Mustaffa ◽  
M. H. Padzillah
Keyword(s):  
Mass Flow ◽  
Leading Edge ◽  
Maximum Efficiency ◽  
Blade Surface ◽  
Mixed Flow ◽  
Factors Affecting ◽  
Turbine Performance ◽  
Radial Turbine ◽  
Torque Generation ◽  
Edge Surface

A mixed flow turbine is a type of turbine that is used mostly in turbocharger engine for vehicle. The ability of this turbine in obtain maximum efficiency on a wider operating range makes it more favorable compared to axial turbine and radial turbine. In this project, one of the factors affecting turbine performance which is torque has been studied using simulation. The simulation is then being run by varying the mass flow supply to the turbine. In this simulation, torque generation has been identified and plot on the entire blade surface. This torque generation capability is then been compared between 0.25 kg/s, 0.45 kg/s and 0.65 kg/s mass flow. From the simulation, the torque generated is founded to fluctuate along the turbine blade surface. Besides, the torque generated at the leading edge and trailing edge surface are negative. The magnitude of torque generated increases, as the mass flow increased. At the mid span of the blade, torque generated at 0.25 kg/s, 0.45 kg/s and 0.65 kg/s is -3.73 X 10-3Nm, 4.33 X 10-3Nm, and 11.8 X 10-3Nm respectively.

Friction Coefficient Estimate for Threaded Joints Made of Carbon-Carbon Composite Materials

2021 ◽  
pp. 22-28
Author(s):  
M.A. Lyubchenko
Keyword(s):  
Composite Materials ◽  
Friction Coefficient ◽  
Laboratory Tests ◽  
Experimental Studies ◽  
Carbon Composite ◽  
Coefficient Estimate ◽  
Tightening Force ◽  
Torque Wrench ◽  
Carbon Composite Materials ◽  
Threaded Joints

Experimental studies were carried out to estimate the friction coefficients for a screw-nut threaded pair made of spatially reinforced carbon-carbon composite materials (CCCM). Quantitative values were obtained for the thread friction coefficient and nut end friction coefficient. The ultimate screw-in torque for the CCCM threaded pair was determined, and its failure mode at a destructive screw-in torque was established. The laboratory tests were carried out to measure the tightening force. The nut screw-in torque was measured using a torque wrench.

Factors Affecting Curling in Rolled Sheet

1973 ◽  
Vol 95 (2) ◽  
pp. 103-106 ◽  
Author(s):  
C. R. Heiple
Keyword(s):  
Leading Edge ◽  
Reduction Ratio ◽  
The Other ◽  
Rolled Sheet ◽  
Roll Speed ◽  
Factors Affecting ◽  
Height Reduction ◽  
Bottom Roll ◽  
Increasing Temperature ◽  
Roll Gap

The influence of several rolling parameters on curling during the rolling of sheet was investigated. The material studied was primarily 0.5 in. thick 2024 aluminum. The factors studied were different top and bottom roll diameters, differential strength through the thickness of the sheet, lubrication, roll-table height, reduction ratio, temperature, roll speed, and a beveled leading edge. The sheet curled toward the smaller roll, away from the better lubricated side, toward the strong side if one side was stronger than the other, and up when the entrance roll table was too high. Curling increased for greater reductions (under the conditions studied) and also increased slightly with increasing temperature. Curling was not sensitive to roll speed or a beveled leading edge. The curling observed can generally be explained on the basis of a shear in the roll gap because of different locations of the neutral points along the arcs of contact for the two rolls. Curling observed when one side of the sheet is significantly softer than the other appears to be due to greater elongation of the soft side during rolling.

XXII.—A Quantitative Study of Spermatozoan Nucleus Length in Drosophila melanogaster (Meig).

1964 ◽  
Vol 68 (4) ◽  
pp. 327-335
Author(s):  
N. S. Sidhu
Keyword(s):  
Drosophila Melanogaster ◽  
Quantitative Study ◽  
Coefficient Of Variation ◽  
Logarithmic Transformation ◽  
Quantitative Variation ◽  
Length Variation ◽  
Preparation Technique ◽  
Squash Preparation ◽  
Factors Affecting ◽  
High Coefficient

SynopsisA squash-preparation technique for the measurement of nucleus lengths in permanent preparations of the spermatozoa of Drosophila melanogaster is described. Prefixation gave longer nuclei, but the degree of pressure used in making the squash did not affect nucleus length. Variation in nucleus length between the spermatozoa of a male was fairly high (coefficient of variation 14 per cent). Smaller, though significant, differences existed between means of males within culture bottles, but there were no significant differences between means of duplicate culture bottles. There was a little evidence of heterogeneity of within-male variances. A logarithmic transformation of data before analysis was indicated. These observations provide a hitherto missing background for planning experiments in quantitative variation designed to throw light on genetic and other factors affecting the dimensions of Drosophila spermatozoa.

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