Characteristic Analysis of Grinding Point Movement in Grinding Aspheric with Arc Envelope Grinding Method

2011 ◽  
Vol 418-420 ◽  
pp. 1202-1207
Author(s):  
Xu Guang Zhou ◽  
Qiu Sheng Yan ◽  
Jue Dai ◽  
Ling Ye Kong
Keyword(s):  
Angular Velocity ◽  
Feed Rate ◽  
Motion Velocity ◽  
Characteristic Analysis ◽  
Important Method ◽  
Severe Wear ◽  
Grinding Method ◽  
The Relationship

It is an important method to machine revolution aspheric with Arc Envelope Grinding Method（AEGM）. In this article, the relationship between the grinding point of the wheel and its position is analyzed, and motion law of the grinding point is discussed in grinding aspheric. According to motion velocity of the grinding point , the concrete position of severe wear for the wheel can be calculated out theoretically. It is possible to achieve even angular velocity of the grinding point by adjusting the wheel feed rate, so the angular velocity of wheel movement is optimized, which provide confirm base for improving the precision of grinding aspheric.

Velocity Characteristics of the Wheel in Grinding Axisymmetric Aspheric with AEGM

2012 ◽  
Vol 472-475 ◽  
pp. 921-926
Author(s):  
Xu Guang Zhou ◽  
Qiu Sheng Yan ◽  
Guang Li Zhu ◽  
Ling Ye Kong
Keyword(s):  
Angular Velocity ◽  
Cross Section ◽  
Feed Rate ◽  
Grinding Wheel ◽  
Grinding Method ◽  
Meridional Cross Section ◽  
Z Value ◽  
Section Curve ◽  
Coordinate Changes ◽  
The Relationship

It is an important method to machine revolution aspheric with Arc Envelope Grinding Method（AEGM）. CNC system controls the feed rate of the arc center of the end of the wheel in grinding, Disk-shaped grinding wheel processing curve (ie, cross-section curve of rotary aspheric) and motion curve of the arc center of the wheel are equidistant curves each other . Based on the analysis of the angular velocity (ω) of the grinding point, the relationship between the feed rate of the arc of the wheel (υ0) and the feed rate of the grinding point (υ) is analyzed, the feed rate and the angular velocity of the grind point is discussed when the eccentricity of the meridional cross-section curve take different values. The results show: 1) the feed rate of the grinding pointυ=υ0±ωr; 2)ω is changing in grinding, When the caliber of axisymmetric aspheric (ie, z value) is small, ω will change slowly, otherwise, ω will change rapidly when the caliber of axisymmetric aspheric is large; 3) the ratio of υ/υ0 will change with the z-axis coordinate changes. υ/υ0is larger when the caliber of axisymmetric aspheric is smaller. By analyzing ,υ/υ0 and other parameters, the motion law of the wheel is obtained, which will provide confirm base for optimizing feed rate in grinding and improve the precision of grinding.

Text and Gloss

2020 ◽  
pp. 923-942
Author(s):  
Greti Dinkova-Bruun
Keyword(s):  
Middle Ages ◽  
Important Method ◽  
Way Of Thinking ◽  
The Relationship

This chapter examines the relationship between a text and its glosses, using examples from the later Middle Ages. It discusses interlinear glosses, marginal glosses, catena commentaries, as well as the layout of glosses. It argues that medieval glossing represented a new way of thinking and an important method for engaging with the literary and scholarly tradition.

The Relationship between Consistency of Propulsive Cycles and Maximum Angular Velocity during Wheelchair Racing

2008 ◽  
Vol 24 (3) ◽  
pp. 280-287 ◽  
Author(s):  
Yong “Tai” Wang ◽  
Konstantinos Dino Vrongistinos ◽  
Dali Xu
Keyword(s):  
Angular Velocity ◽  
Upper Limb ◽  
Wheelchair Propulsion ◽  
Upper Arm ◽  
Wheelchair Athletes ◽  
Angular Velocities ◽  
Limb Kinematics ◽  
Analysis System ◽  
The Right ◽  
The Relationship

The purposes of this study were to examine the consistency of wheelchair athletes’ upper-limb kinematics in consecutive propulsive cycles and to investigate the relationship between the maximum angular velocities of the upper arm and forearm and the consistency of the upper-limb kinematical pattern. Eleven elite international wheelchair racers propelled their own chairs on a roller while performing maximum speeds during wheelchair propulsion. A Qualisys motion analysis system was used to film the wheelchair propulsive cycles. Six reflective markers placed on the right shoulder, elbow, wrist joints, metacarpal, wheel axis, and wheel were automatically digitized. The deviations in cycle time, upper-arm and forearm angles, and angular velocities among these propulsive cycles were analyzed. The results demonstrated that in the consecutive cycles of wheelchair propulsion the increased maximum angular velocity may lead to increased variability in the upper-limb angular kinematics. It is speculated that this increased variability may be important for the distribution of load on different upper-extremity muscles to avoid the fatigue during wheelchair racing.

Research State of Combine Threshing Unit Monitoring System and Insufficiency and Emphasis in China

2012 ◽  
Vol 246-247 ◽  
pp. 1026-1030
Author(s):  
Cheng Wen Zhang ◽  
Chong You Wu ◽  
Su Zhen Wang
Keyword(s):  
United States ◽  
Real Time ◽  
Monitoring System ◽  
Feed Rate ◽  
Travel Speed ◽  
Research Status ◽  
Drive Pulley ◽  
Fault Diagnostic ◽  
The Relationship

This article summarizes the development of United States, Japan and other foreign combine threshing part monitoring system. Meanwhile it analyses the research status of China from two aspects of fault diagnostic and the relationship with feed rate. Which is specifically illustrated the present researching status of the fault alarm, fault warning, troubleshooting, and the relationship be-tween feed rate and travel speed, roller torque, the drive pulley oil pressure relations. At last it con-cludes the insufficiency in the present studies and points out the direction of the strengthened re-search that is model of real-time controlling about feed rate.

Experimental Assessment of Effect of Backlash Control Parameters on Quadrant Protrusions of Circular Tests for CNC Machine Tools

2020 ◽  
Vol 19 (01) ◽  
pp. 65-85
Author(s):  
Chuan-Hsun Hsu ◽  
Chi-Hsiang Wang ◽  
Syh-Shiuh Yeh
Keyword(s):  
Machine Tool ◽  
Feed Rate ◽  
Machine Tools ◽  
Search Algorithm ◽  
Cnc Machine Tools ◽  
Control Parameters ◽  
Cnc Machine ◽  
Circular Test ◽  
Binary Search Algorithm ◽  
The Relationship

Backlash, friction, and servo lag factors often result in protrusion or segment difference phenomenon in the moving speed reversal of a machine tool’s moving table. This phenomenon can be improved by adjusting the backlash control parameters of the machine tool controller, but the control parameters must vary with the feed rate and payload of the moving table. Therefore, this study performed the circular test process for CNC machine tools, and used different feed rate, radius, and payload motion conditions to discuss the effect of backlash control parameters on quadrant protrusions. First, this study used parameter-range reduction combined with the Taguchi method and the binary search algorithm to search for the optimal backlash control parameters in the parameter setting range, so that the machine tool could have preferable quadrant protrusion performance when executing circular tests. Afterward, the correlation of the moving table feed rate, radius, and payload to the quadrant protrusion was analyzed according to the experimental results. The results indicated that the machine tool moving table feed rate had the most apparent effect on quadrant protrusions, and the relationship between the payload and quadrant protrusion was influenced by the moving table feed rate and circular radius simultaneously.

scholarly journals Association between platelet count and osteoarthritis in women older than 50 years

2020 ◽  
Vol 12 ◽  
pp. 1759720X2091286
Author(s):  
Yu-Jin Kwon ◽  
Il-Hyun Koh ◽  
Kwangho Chung ◽  
Yong-Jae Lee ◽  
Hyoung-Sik Kim
Keyword(s):  
Platelet Count ◽  
Confidence Intervals ◽  
Multiple Logistic Regression Analysis ◽  
Odds Ratios ◽  
Characteristic Analysis ◽  
Cross Sectional ◽  
Platelet Counts ◽  
Health And Nutrition ◽  
Inflammatory Processes ◽  
The Relationship

Background: Osteoarthritis (OA) is a multifactorial disease involving inflammatory processes. Platelets play important roles in both hemostasis and the inflammatory response; however, the relationship between platelet count and OA is unclear. Our aim was to evaluate the association between platelet count and knee and hip OA in Korean women. Methods: In this cross-sectional designed study, we included a total of 6011 women aged ⩾50 years from the 2010–2013 Korea National Health and Nutrition Examination Survey. Knee and hip OA were defined as Kellgren–Lawrence grade ⩾2 and presence of knee or hip pain, respectively. Platelet counts were divided into quartiles as follows: Q1, 150–212 (103/µl); Q2, 213–246 (103/µl); Q3, 247–283 (103/µl); and Q4, 284–450 (103/µl). Multiple logistic-regression analysis was conducted to calculate odds ratios and 95% confidence intervals. Receiver operating characteristic analysis was performed to determine the optimal platelet count cut-off with which to discriminate participants with knee and/hip OA versus those without OA. Results: Of the 6011 participants, 1141 (18.1%) had knee or hip OA. The mean age of participants without OA was 60.6 years, and that of participants with OA was 68.0 years. Compared with the lowest quartile, odds ratios (95% confidence intervals) for OA were 1.08 (0.84–1.39) for Q2, 0.94 (0.73–1.23) for Q3, and 1.35 (1.08–1.69) for Q4 after adjusting for confounders. The prevalence of OA was significantly higher with platelet counts ⩾288 × 103/µl, compared with platelet counts <288 × 103/µl. Conclusion: High platelet counts within the normal range are significantly associated with knee and hip OA.

scholarly journals Stiffness Calculation Method and Stiffness Characteristic Analysis of Bolted Connectors

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Shi-kun Lu ◽  
Deng-xin Hua ◽  
Yan Li ◽  
Fang-yuan Cui ◽  
Peng-yang Li
Keyword(s):  
Surface Roughness ◽  
Bolted Joints ◽  
Joint Surface ◽  
Characteristic Analysis ◽  
Surface Stiffness ◽  
Stiffness Characteristic ◽  
Calculation Results ◽  
Bolt Connection ◽  
The Relationship ◽  
Effect Of Surface

At present, few scholars have studied the effect of surface roughness on assembly stiffness. The influence of the joint surface stiffness on the overall stiffness is neglected. In this paper, a new method for calculating the stiffness of bolted joints is presented. The effect of joint surface stiffness on the overall stiffness is considered. Firstly, the relationship between load and displacement between cylinder and cylinder (including the joint surface with certain roughness) is studied, and the stiffness characteristic expression of the joint surface is obtained; the results are compared with the traditional stiffness calculation theory, and then, the influence of bolt connection surface on bolt connection is studied and compared with the stiffness calculation results of traditional bolt connection. The results show that the theoretical model presented in this paper is more practical.

The Relationship between Feed Rate and Point Angle of a Twist Drill Bit When Drilling Bone

1980 ◽  
Vol 9 (3) ◽  
pp. 137-142
Author(s):  
J K Davis ◽  
C J Jackson ◽  
I Scott
Keyword(s):  
Shear Flow ◽  
Feed Rate ◽  
Thermal Effects ◽  
Orthogonal Cutting ◽  
Human Bone ◽  
Bovine Bone ◽  
Drill Bit ◽  
Twist Drill ◽  
Dynamic Shear ◽  
The Relationship

The work described in this paper was carried out in two parts. The first part consisted of evaluating the machining constants and the dynamic shear flow strengths of bovine bone from orthogonal cutting and drilling tests. The second part of the work arose from investigation into the thermal effects of drilling human bone during which certain trends were observed when comparing feed rate and point angle for fixed values of thrust. Some measure of agreement was found between these two independent pieces of work. Bera and Bhattacharrya's analytical equation for the thrust produced when drilling metals has been modified for anisotropic materials such as bone.

Characteristic Analysis of Metal Trough Faces Cut by Pre-Mixed Abrasive Waterjet

2011 ◽  
Vol 63-64 ◽  
pp. 740-744
Author(s):  
Bai Sheng Nie ◽  
Ming Zhang ◽  
Jun Qing Meng ◽  
Hui Wang ◽  
Ru Ming Zhang
Keyword(s):  
Formation Mechanism ◽  
Sem Analysis ◽  
Abrasive Waterjet ◽  
Characteristic Analysis ◽  
Cutting Mechanism ◽  
Cutting Efficiency ◽  
Cutting Depth ◽  
Topographic Characteristics ◽  
Awj Cutting ◽  
The Relationship

In order to improve the cutting efficiency of abrasive waterjet (AWJ), the relationship between pre-mixed AWJ cutting depth and pressure was experimentally studied. Then, through analysis of the cutting results, the topographic characteristics and formation mechanism of the cut trough faces were investigated. Moreover, through comparing the effects of different jet pressures on the topographic characteristics of AWJ cut trough faces and the SEM analysis of the cut trough faces at different pressures and depths, the effects of pre-mixed AWJ cutting mechanism on the characteristics of cut trough faces were investigated, and the characteristics of the trough faces of metals cut by pre-mixed AWJ were analyzed.

Sign in / Sign up

Export Citation Format

Share Document