Conditions for Wall Thickness Reduction in Hollow Sinking of SUS304 Tubes With Drawing Speed Control in Entrance and Exit Sides of Die

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Takuma Kishimoto ◽  
Shiori Gondo ◽  
Kosuke Takemoto ◽  
Kenichi Tashima ◽  
Shinsuke Suzuki
Keyword(s):  
Wall Thickness ◽  
Threshold Value ◽  
Back Stress ◽  
Thickness Reduction ◽  
Speed Ratio ◽  
Geometric Condition ◽  
Outer Diameter ◽  
Cross Sectional ◽  
Drawing Speed ◽  
Inner Diameter

Abstract In this study, the conditions for wall thickness reduction in hollow sinking were obtained by tube drawing experiments in which the drawing speed ratio was controlled under three conditions (1.09, 1.11, and 1.14). These conditions have not been found in the history of hollow sinking. The results of the experiment and the theoretical formulas indicate that the geometric condition is obtained from the figure of the ratio of inner diameter to outer diameter after drawing against that ratio before drawing. Furthermore, the ratio of the inner diameter to the outer diameter after drawing must be above the constant wall thickness line derived from the cross-sectional change. To satisfy this geometric condition, the drawing speed ratio must be larger than the threshold value, which is obtained from the ratio of the inner diameter to the outer diameter before drawing, and the reduction of the die. However, the value of the back stress approaches that of the strength of the tube when the drawing speed ratio increases. A simple dynamical model shows that parameters other than the drawing speed ratio do not significantly decrease the back stress during drawing. Therefore, the drawing speed ratio should be set such that the tube does not break.

scholarly journals Cross-sectional analysis of tubular polymer semi-finished products using ultrasound in comparison with other measuring methods

2020 ◽  
Vol 6 (3) ◽  
pp. 151-154
Author(s):  
Olga Sahmel ◽  
Stefan Siewert ◽  
Wolfram Schmidt ◽  
Klaus-Peter Schmitz ◽  
Niels Grabow
Keyword(s):  
Wall Thickness ◽  
Biomedical Engineering ◽  
Measuring Method ◽  
Outer Diameter ◽  
Micro Computed Tomography ◽  
Cross Sectional ◽  
Biodegradable Poly ◽  
Ultrasonic Measuring ◽  
Inner Diameter ◽  
Sectional Analysis

AbstractIn the sector of biomedical engineering and implant technology, high-precision geometry is often decisive for successful end product functionalization. Especially in the production of tubular polymer semi-finished products, e.g. for stent fabrication, it is important to assure the desired parameters, such as inner and outer diameter and wall thickness. Within the current study we analyzed semifinished products for manufacturing of polymeric stents using three different methods. Biodegradable poly-L-lactide (PLLA) tubes were examined by means of micro computed tomography, ultrasonic scanning and scanning electron microscopy. The final evaluation presents clear advantages of the ultrasonic measuring method for the measurement of outer and inner diameter and wall thickness.

scholarly journals Evaluation of the Lower Punctum Parameters and Morphology Using Spectral Domain Anterior Segment Optical Coherence Tomography

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Riham S. H. M. Allam ◽  
Rania A. Ahmed
Keyword(s):  
Optical Coherence Tomography ◽  
Anterior Segment ◽  
Normal Subjects ◽  
Cross Sectional Study ◽  
Spectral Domain ◽  
Outer Diameter ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Air Bubble ◽  
Inner Diameter

Purpose. To study features of the lower punctum in normal subjects using spectral domain anterior segment optical coherence tomography (SD AS-OCT).Methods. Observational cross-sectional study that included 147 punctae (76 subjects). Punctae were evaluated clinically for appearance, position, and size. AS-OCT was used to evaluate the punctal shape, contents, and junction with the vertical canaliculus. Inner and outer diameters as well as depth were measured.Results. 24 males and 52 females (mean age44±14.35 y) were included. Lower punctum was perceived by OCT to be an area with an outer diameter (mean412.16±163 μm), inner diameter (mean233.67±138.73 μm), and depth (mean251.7±126.58 μm). The OCT measured outer punctum diameter was significantly less than that measured clinically (P: 0.000). Seven major shapes were identified. The junction with the vertical canaliculus was detectable in 44%. Fluid was detected in 34%, one of which had an air bubble; however, 63% of punctae showed no contents and 4% had debris.Conclusions. AS-OCT can be a useful tool in understanding the anatomy of the punctum and distal lacrimal system as well as tear drainage physiology. Measuring the punctum size may play a role in plugs fitting.

Structural characterization of the fullerene nanotubes prepared by the liquid–liquid interfacial precipitation method

2005 ◽  
Vol 20 (3) ◽  
pp. 688-695 ◽  
Author(s):  
Kun'ichi Miyazawa ◽  
Jun-ichi Minato ◽  
Tetsuro Yoshii ◽  
Masahisa Fujino ◽  
Tadatomo Suga
Keyword(s):  
Linear Relationship ◽  
Wall Thickness ◽  
Structural Characterization ◽  
Tube Wall ◽  
Precipitation Method ◽  
Outer Diameter ◽  
Tubular Structures ◽  
Growth Axis ◽  
Inner Diameter

Fine tubular fibers composed of C60 and C70 fullerene molecules were successfully fabricated by the liquid–liquid interfacial precipitation method. The walls of the tubular fibers were crystalline, and the fullerene molecules were densely packed along the growth axis of tube wall. The tubular structures are called “fullerene nanotubes.” The inner diameter and the outer diameter of C70 tubes showed a linear relationship, suggesting a constant wall thickness of the tubes. The tubular structures composed of C70 molecules could be formed when their diameter was larger than about 240 nm. The fullerene tubes were successfully fabricated by using a C60-C70 soot as well. The formation of fullerene nanotubes can be understood by assuming a mechanism of core dissolution of the solvated fullerene nanowhiskers.

Remote Measurement of the Pipe Thickness Reduction by Microwaves

2007 ◽  
Author(s):  
Yang Ju
Keyword(s):  
Resonance Frequency ◽  
Wall Thickness ◽  
Large Scale ◽  
Microwave Signal ◽  
Thickness Reduction ◽  
Remote Measurement ◽  
Copper Pipe ◽  
Inner Diameter

A method which can inspect a pipe in a large scale and measure the thickness reduction remotely was demonstrated. A copper pipe having 17 mm inner diameter, 1 mm wall thickness, and 900 mm length was measured. The thickness reduction having the value from 10% to 80% of the wall thickness was detected significantly. By building up a resonance for the microwave signal propagated in the pipe, it is possible to determine the thickness reduction using the measured resonance frequency.

scholarly journals A New Method for Precision Measurement of Wall-Thickness of Thin-Walled Spherical Shell Parts

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 467
Author(s):  
Jiang Guo ◽  
Yongbo Xu ◽  
Bo Pan ◽  
Juntao Zhang ◽  
Renke Kang ◽  
...  
Keyword(s):  
Spherical Shell ◽  
Wall Thickness ◽  
High Surface ◽  
Measurement Data ◽  
Outer Diameter ◽  
Surface Errors ◽  
Inner Diameter ◽  
Thickness Error ◽  
Thin Walled ◽  
Physics Experiments

Thin-walled parts are widely used in shock wave and detonation physics experiments, which require high surface accuracy and equal thickness. In order to obtain the wall thickness of thin-walled spherical shell parts accurately, a new measurement method is proposed. The trajectories, including meridian and concentric trajectories, are employed to measure the thickness of thin-walled spherical shell parts. The measurement data of the inner and outer surfaces are unified in the same coordinate system, and the thickness is obtained based on a reconstruction model. The meridian and concentric circles’ trajectories are used for measuring a spherical shell with an outer diameter of Φ210.6 mm and an inner diameter of Φ206.4 mm. Without the data in the top area, the surface errors of the outer and inner surfaces are about 5 μm and 6 μm, respectively, and the wall-thickness error is about 8 μm with the meridian trajectory.

Experimental Study on Residual Cross-Sectional Flattening of Thin-Walled Pipes Under Pure Plastic Bending

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Ziqian Zhang
Keyword(s):  
Cross Section ◽  
Wall Thickness ◽  
Residual Deformation ◽  
Outer Diameter ◽  
Cross Sectional ◽  
Plastic Bending ◽  
Thin Walled Pipe ◽  
Bending Radius ◽  
Thin Walled ◽  
The Cross

Abstract Cross-sectional ovalization (ovalization) usually occurs when thin-walled pipe is subjected to large plastic bending. This paper is concerned with residual deformation of thin-walled pipe's cross section in a radial direction when external bending moment is removed. In order to clarify the fundamental ovalization characteristics, find out what factors influence the residual flattening (value of ovalization), the ovalization behavior is investigated experimentally. The experiments are carried out on 21 stainless steel specimens with different geometric parameters under different bending radii by means of a four-point pure bending device. The residual cross-sectional flattenings are monitored continuously by scanning the cross section periodically along the circumferential direction. From the experimental results, it is observed that the cross-sectional shape of the thin-walled pipe is not perfect standard ellipse, and the appearance of the maximum residual flattening is usually found in the direction normal to the neutral surface. It is also revealed the relationships between the residual flattening and the bending radius, the wall thickness, and the pipe outer diameter, i.e., the residual flattening increases as the bending radius and the wall thickness reduce, but it increases as the outer diameter increases. These results are expected to find their potential application in thin-walled pipe bending operation.

Simulation of Ironing Process for Bullet Case to Get Minimum Forming Force with Variation of Die Angle and Reduction Wall Thickness

2016 ◽  
Vol 836 ◽  
pp. 197-202 ◽  
Author(s):  
M. Nushron Ali Mukhtar ◽  
I. Made Londen Batan ◽  
Bambang Pramujati ◽  
Agus Sigit Pramono
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Process Parameters ◽  
Wall Thickness ◽  
Strength Calculation ◽  
Thickness Reduction ◽  
Material Strength ◽  
Outer Diameter ◽  
Forming Force ◽  
Simulation Results

This study described how the ironing process to manufacture 20 mm caliber bullet case. For this purpose, the first step is analyzing the process parameters, and then calculates the forces needed to make the formation of bullet case. Through the analysis of the process it is known, that the ironing process parameters most influential to the magnitude of forming force are the die angle α and the reduction of the wall thickness. In this study a simulation is conducted to determine a minimum required of forming force until the process successful. That means the required bullet case accordance with the determined specifications and geometry. The material used for bullet case caliber 20 mm is brass Cu30% Zn 70% early-shaped cup with 33.5 mm outer diameter, 3 mm thick and 37 mm high. Based on material strength calculation, the ironing force is determined with value of 50.01 kN. By using this value the maximum allowable wall reduction thickness in the ironing process is 26.7%. The simulation is carried out using finite element method on a variety of die angle such as α = 5°, 10°, 15°, 20° and 25° respectively. The simulation results show that the shell cannot through the die on each angle die. Similarly, in variation of reduction by 5%, 10%, 15%, 20% and 25%, the ironing process is also unsuccessful. However, by load of 138 kN, in the 26.7% reduction and at die angle α=5°, the ironing process to produce cylinder is successfully. Similarly by the same of wall thickness reduction, with force of 148 kN and the die angle of 10°, the ironing process is also successfully to fulfill the bullet case with a specified geometry.

scholarly journals Evaluation of Fecal Calprotectin, D-Lactic Acid and Bedside Gastrointestinal Ultrasound Image Data for the Prediction of Acute Gastrointestinal Injury in Sepsis Patients

2021 ◽  
Vol 3 ◽  
Author(s):  
Junlu Li ◽  
Yanbo Ren ◽  
Chang Gao ◽  
Kaili Zhang ◽  
Fuwen Zheng ◽  
...  
Keyword(s):  
Small Intestine ◽  
Lactic Acid ◽  
Wall Thickness ◽  
Diameter Ratio ◽  
Cross Sectional Area ◽  
Gastric Antrum ◽  
Control Group ◽  
Outer Diameter ◽  
Sectional Area ◽  
Cross Sectional

Objective: To investigate the early warning and prognostic evaluation of fecal calprotectin (FC), D-lactic acid, and bedside gastrointestinal ultrasound (B-GIUS) data for acute gastrointestinal injury (AGI) in sepsis patients.Main Method: Sepsis patients were grouped based on the presence or absence of AGI into AGI and non-AGI groups. Healthy volunteers of the same period were selected as the control group. FC, B-GIUS data, D-lactic acid, etc. were collected on the 1st, 3rd and 7th days of admission. Twenty-eight-day mortality was recorded.Main Results: FC, D-lactic acid levels, gastric antrum cross-sectional area, and small intestine wall thickness were significantly increased in group A and B (P < 0.05); furthermore, inner-to-outer diameter ratio and cross-sectional area of small intestine were lower than those in the control group (P < 0.05). FC, D-lactic acid, gastric antrum cross-sectional area and small intestine wall thickness in AGI group were higher than those in non-AGI group (P < 0.05). Inner-to-outer diameter ratio and cross-sectional area of small intestine in AGI group were smaller than those in non-AGI group (P < 0.05). There was no difference in the thickness, inner-to-outer diameter ratio nor the cross-sectional area ratio of colon between AGI and non-AGI groups (P > 0.05). AUC for D-lactic acid was 0.881, which was higher than FC's (0.74). When the D-lactic acid cutoff value was 22.16 μmol/L, the sensitivity was 77.9% and the specificity was 92% for the prediction of AGI in sepsis. AUC for the cross-sectional area of the gastrointestinal antrum was 0.657, which was higher than the small intestine thickness's (0.629). When the gastric antrum cross-sectional area was larger than 4.20 cm2, the sensitivity was 64% and the specificity was 65.3%.Conclusion: D-Lactic acid and FC were early diagnostic indicators for sepsis with AGI, and D-lactic acid was the superior indicator. The gastric antrum cross-sectional area and the small intestine wall thickness had an early warning effect, and the prediction of the gastric antrum cross-sectional area was superior to that of the latter. Because it is non-invasive and convenient, B-GIUS can help in the diagnosis of sepsis with AGI.

Comparison of Dimensions and Residual Forces of Various Orthodontic Elastomeric Ligatures

2013 ◽  
Vol 746 ◽  
pp. 315-320 ◽  
Author(s):  
Niwat Anuwongnukroh ◽  
Nittaya Jiraanankul ◽  
Surachai Dechkunakorn ◽  
Pornkiat Churnjitapirom ◽  
Peerapong Tua-Ngam
Keyword(s):  
Rank Correlation ◽  
Outer Diameter ◽  
Cross Sectional ◽  
Force Decay ◽  
Significant Difference ◽  
Extension Force ◽  
Inner Diameter ◽  
Residual Force ◽  
Mean Differences ◽  
Digital Caliper

Objective: The study aimed to compare dimensions and residual forces of various commercial type orthodontic elastomeric ligatures available in Thailand. Materials and Methods: The study compared 5 types of elastomeric ligatures: MU-MTEC, UnitekTM, MorelliTM, WelovehealthTM and DentsplyTM. A digital caliper was used to measure dimensions: the inner and outer diameters and cross-sectional thickness. Then the initial extension force and residual force on days 1, 2, 3, 4, 5, 6, 7, 14 and 28 were measured according to ISO 21606: 2007. The data were analyzed with the Kruskal-Wallis test and Spearmans rank correlation. Results: No significant difference was found between the outer diameter of MU-MTEC and WelovehealthTM. However, significant mean differences were found in dimensions among the other ligature types. The lowest mean for inner diameter and cross sectional thickness was found in UnitekTM and the lowest mean for outer diameter was found in MorelliTM. The highest mean inner diameter, outer diameter and cross sectional thickness was found in Dentsply, UnitekTM, and MorelliTM, respectively. In terms of initial extension force, significant differences (p<0.001) were found among all samples. The highest mean was found in DentsplyTM (2.69 N) and the lowest mean was found in WelovehealthTM (1.80 N). All samples had rapid force degradation at about 42.21-56.23% after 24 hours, with a slow degradation rate until Week 1 and a constantly stable rate from Weeks 1-4. The greatest force decay on the first day was found in MorelliTM (56.23%). At 28 days, the residual force for all types of elastomeric ligature was about 31.97-46.84%. Conclusion: All 5 brands of commercial elastomeric ligatures had different dimensions, initial extension forces and residual forces. The correlation between brand and dimension, initial extension force and residual force showed different patterns. All elastomeric ligatures had greater force decay on the first day (residual force 43.77 57.79%), then slightly decreased over 28 days.

Principles of designing secondary channels along the river rhine for the benefit of ecological restoration

1995 ◽  
Vol 31 (8) ◽  
pp. 379-382 ◽  
Author(s):  
M. H. I. Schropp
Keyword(s):  
Ecological Restoration ◽  
Threshold Value ◽  
Main Channel ◽  
River Rhine ◽  
Secondary Channel ◽  
Frequency Curve ◽  
Cross Sectional ◽  
Design Value ◽  
Ecological Targets ◽  
Flow Velocities

Secondary channels present a favourable opportunity for ecological restoration of the River Rhine and its branches. However, they have to be fitted into the landscape without affecting existing interests such as inland shipping and protection against flooding. Also the ecological targets have to be met with a minimum of human interference. In this article some design principles for secondary channels are presented in which these aspects are taken into account. To avoid silting up of the secondary channel it is recommended to prevent sediment from entering the channel at all. Flow velocities have to be below the threshold value for initiation of motion of sediment, but still high enough to satisfy the ecological targets. The secondary channel discharge is a function of the maximum allowable aggradation of the main channel. Discharge and flow velocities together determine the required cross-sectional area and thus the design value of the bank slopes. In order to have flowing water in the secondary channel all year round, the thalweg level is to be chosen on the basis of the water level frequency curve of the main channel.

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