MINIMUM WALL THICKNESS OF HOLLOW THREADED PARTS IN THREE-DIE COLD THREAD ROLLING

2009 ◽  
Author(s):  
HUIPING QI ◽  
YONGTANG LI ◽  
JIANHUA FU ◽  
ZHIQI LIU
Keyword(s):  
Wall Thickness ◽  
Thread Rolling

MINIMUM WALL THICKNESS OF HOLLOW THREADED PARTS IN THREE-DIE COLD THREAD ROLLING

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6112-6117 ◽  
Author(s):  
HUIPING QI ◽  
YONGTANG LI ◽  
JIANHUA FU ◽  
ZHIQI LIU
Keyword(s):  
Wall Thickness ◽  
High Efficiency ◽  
Low Cost ◽  
Work Piece ◽  
Forming Process ◽  
Minimum Thickness ◽  
Thread Rolling ◽  
Thin Walled ◽  
Rolling Technology ◽  
Good Agreement

The cold thread rolling technology was developed rapidly in recent years due to its high efficiency, low cost and perfect mechanical properties of its production. However, researches on the precise thread rolling of the hollow parts were very few. Traditionally, the minimum thickness of the thin-walled threaded parts by thread rolling was mainly determined by the empirical (trial and error) methods. In this study, the forming process of thin-walled thread parts rolled with three thread rolling dies was analyzed. The stress state of the hollow work piece was obtained by solving the statically indeterminate problems. Then, the equations for the minimum wall thickness were derived. Experiments are also performed. The experimental results are generally in good agreement with those by the current theoretical analysis. It could be concluded that the analysis presented in this study can provide a good guidance for the thread rolling of hollow parts.

Assessment of Myocardial Viability in Persistent Defects on Thallium-201 SPECT after Reinjection Using Gradient-Echo MRI

1996 ◽  
Vol 35 (05) ◽  
pp. 146-152 ◽  
Author(s):  
A. Kögler ◽  
H.-A. Schmitt ◽  
D. Emrich ◽  
H. Kreuzer ◽  
D. L. Munz ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Myocardial Viability ◽  
Cardiac Cycle ◽  
Single Photon ◽  
Contractile Function ◽  
Left Ventricular ◽  
Wall Thickening ◽  
Gradient Echo ◽  
Systolic Wall Thickening

SummaryThis prospective study assessed myocardial viability in 30 patients with coronary heart disease and persistent defects despite reinjection on TI-201 single-photon computed tomography (SPECT). In each patient, three observers graded TI-201 uptake in 7 left ventricular wall segments. Gradient-echo magnetic resonance imaging in the region of the persistent defect generated 12 to 16 short axis views representing a cardiac cycle. A total of 120 segments were analyzed. Mean end-diastolic wall thickness and systolic wall thickening (± SD) was 11.5 ± 2.7 mm and 5.8 ± 3.9 mm in 48 segments with normal TI-201 uptake, 10.1 ± 3.4 mm and 3.7 ± 3.1 mm in 31 with reversible lesions, 11.3 ± 2.8 mm and 3.3 ± 1.9 mm in 10 with mild persistent defects, 9.2 ± 2.9 mm and 3.2 ±2.2 mm in 15 with moderate persistent defects, 5.8 ± 1.7 mm and 1.3 ± 1.4 mm in 16 with severe persistent defects, respectively. Significant differences in mean end-diastolic wall thickness (p <0.0005) and systolic wall thickening (p <0.005) were found only between segments with severe persistent defects and all other groups, but not among the other groups. On follow-up in 11 patients after revascularization, 6 segments with mild-to-moderate persistent defects showed improvement in mean systolic wall thickening that was not seen in 6 other segments with severe persistent defects. These data indicate that most myocardial segments with mild and moderate persistent TI-201 defects after reinjection still contain viable tissue. Segments with severe persistent defects, however, represent predominantly nonviable myocardium without contractile function.

CT Measurement of Wall Thickness of Early Gastric Cancer: Correlation with Upper GI Series

1995 ◽  
Vol 32 (3) ◽  
pp. 453
Author(s):  
Sung Hoon Chung ◽  
Hyun Sook Kim ◽  
In Oak Ahn ◽  
Goo Lee ◽  
Joon Hee Joh
Keyword(s):  
Gastric Cancer ◽  
Early Gastric Cancer ◽  
Wall Thickness ◽  
Upper Gi ◽  
Upper Gi Series ◽  
Ct Measurement

Performance study of RTV-2 Silicone Rubber Material For Soft Actuator by Experimental and Numerical methods: The Effect of Inflation Pressure and Wall Thickness

2020 ◽  
Vol 17 (1) ◽  
pp. 7524-7532 ◽  
Author(s):  
Deepak D. ◽  
Nitesh Kumar ◽  
Shreyas P. Shetty ◽  
Saurabh Jain ◽  
Manoj Bhat
Keyword(s):  
Numerical Methods ◽  
Wall Thickness ◽  
Silicone Rubber ◽  
Inflation Pressure ◽  
Performance Study ◽  
Rubber Material ◽  
Soft Actuator ◽  
Alternative Materials ◽  
Load Carrying ◽  
Influential Parameters

The expensive nature of currently used materials in the soft robotic industry demands the consideration of alternative materials for fabrication. This work investigates the performance of RTV-2 grade silicone rubber for fabrication of a soft actuator. Initially, a cylindrical actuator is fabricated using this material and its performance is experimentally assessed for different pressures. Further, parametric variations of the effect of wall thickness and inflation pressure are studied by numerical methods. Results show that, both wall thickness and inflation pressure are influential parameters which affect the elongation behaviour of the actuator. Thin (1.5 mm) sectioned actuators produced 76.97% more elongation compared to thick sectioned, but the stress induced is 89.61 % higher. Whereas, the thick sectioned actuator (6 mm) showed a higher load transmitting capability. With change in wall thickness from 1.5 mm to 6 mm, the elongation is reduced by 76.97 %, 38.35 %, 21.05 % and 11.43 % at pressure 100 kPa, 75 kPa, 50 kPa and 25 kPa respectively. The induced stress is also found reduced by 89.61 %, 86.66 %, 84.46 % and 68.68 % at these pressures. The average load carrying capacity of the actuator is found to be directly proportional to its wall thickness and inflation pressure.

Properties of Gliricidia Wood (Gliricidia sepium) lntercropped with Cocoa (Theobroma cocoa) in Malaysia

2014 ◽  
Vol 11 (1) ◽  
pp. 51
Author(s):  
Mohd Helmy Ibrahim ◽  
Mohd Nazip Suratman ◽  
Razali Abd Kader
Keyword(s):  
Cell Wall ◽  
Specific Gravity ◽  
Moisture Content ◽  
Wall Thickness ◽  
Age Groups ◽  
Gliricidia Sepium ◽  
Cell Wall Thickness ◽  
Tree Age ◽  
Lumen Diameter ◽  
Significant Difference

Trees planted from agroforestry practices can become valuable resources in meeting the wood requirements of many nations. Gliricidia sepium is an exotic species introduced to the agricultural sector in Malaysia mainly for providing shade for cocoa and coffee plantations. This study investigates its wood physical properties (specific gravity and moisture content) and fibre morphology (length, lumen diameter and cell wall thickness) of G. sepium at three intervals according to age groups ( three, five and seven years of ages). Specific gravity (0.72) was significantly higher at seven years ofage as compared to five (0.41) and three (0.35) years age group with a mean of 0.43 (p<0.05). Mean moisture content was 58.3% with no significant difference existing between the tree age groups. Fibre diameter (22.4 mm) was significantly lower (p<0.05) for the trees which were three years of age when compared to five and seven years age groups (26.6 mm and 24. 7 mm), respectively. Means of fibre length, lumen diameter and cell wall thickness were 0.83 mm, 18.3 mm, and 6.2 mm, respectively, with no significant differences detected between trees in all age groups. Further calculation on the coefficient of suppleness and runkel ratio suggest that wood from G.sepium may have the potential for insulation board manufacturing and paper making. However, future studies should experiment the utilisation of this species for these products to determine its full potential.

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