DEVELOPMENT OF METHODOLOGY FOR CALCULATING PARAMETERS OF CONTINUOUS FORMING OF PIPE BILLET AT PRODUCTION OF ELECTRIC-WELDED PIPES OF SMALL AND MEDIUM DIAMETER

One of the effective methods for studying any process is its physical modeling, during which it is possible to verify the concepts and hypothesis obtained previously by theoretical modeling. In the laboratory of metal forming of NUST “MISIS” there is ERW mill 30 – 50 for the production and simulation of processes for the continuous forming of longitudinal welded pipes of small and medium diameter, their welding and calibration. This article discusses the deformation zone of a pipe billet, using the first two stands of a molding mill as an example with a calibration of a roll tool for a pipe diam. 50×1.5 mm. Based on the analysis of methods for calculating the parameters of real roll calibers, a model of contact interaction of the pipe billet with the first and second roll open stands was developed and areas of the deformation zone were determined including their sizes: non-intensive and intense impact; input and output contact zones; springing up. Analyzing the conditions of contact interaction of the pipe billet with roll calibers, parameters of the pipe billet in contact with the first-caliber rolls were determined in seven sections, taking into account the features of continuous forming. An analysis of the results has shown that the maximum longitudinal deformation occurred at the edge of the billet in section B – B and was equal to 1.04 %, and for the pipe billet bottom it was 0.92 %. For the experiment, a grid was applied to the pipe billet using a laser engraver. During forming, the trajectory deviation of the pipe billet bottom from horizontal axis was recorded, and sizes of the forming sections were determined. Comparison of theoretical and experimental values has shown that the discrepancy between them does not exceed 7 %.

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Method of surgical treatment of small and medium diameter macular holes with the foveal-sparing internal limiting membrane peeling

Modern technologies in ophtalmology ◽

10.25276/2312-4911-2021-3-213-216 ◽

2021 ◽

pp. 213-216

Author(s):

A.A. Shpak ◽

◽

A.I. Kolesnik ◽

F.A. Avakyan ◽

V.A. Pismenskaya ◽

...

Keyword(s):

Surgical Treatment ◽

Functional Results ◽

Internal Limiting Membrane ◽

Developed Countries ◽

Clear Understanding ◽

Ilm Peeling ◽

Internal Limiting Membrane Peeling ◽

Macular Holes ◽

Air Tamponade ◽

Medium Diameter

Introduction and purpose. Idiopathic macular hole (IMH) is an urgent medical and social problem of the population of developed countries. It is known that microinvasive 3-port vitrectomy with gas-air tamponade is a generally accepted method of surgical treatment of IMH. There is still no clear understanding of the reasons for incomplete functional success in this category of patients, despite the anatomical success.Thus, there is a need to develop and implement in clinical practice a modification of the ILM peeling technique for the treatment of small and medium-diameter of IMH, which would not be inferior in anatomical effectiveness to existing methods and would be accompanied by a less damaging effect on the structures of the retina. Material and methods. The study included 10 patients with a diagnosis of IMH, who underwent a 3-port microinvasive 25G vitrectomy with the preservation of foveal ILM. Results. The analysis of the clinical and functional results of surgical treatment of IMH with the foveal fragment left revealed the complete closure of the macular tear, the absence of gross defects of the ellipsoid zone, an increase in the values of the average visual acuity and microperimetry from the 1st month of dynamic observation. Conclusion. The proposed low-traumatic method of fovea - sparing ILM peeling provides stable anatomical and functional result, the restoration of both morphological and functional parameters, and minimizes the mechanical impact on the retina in the fovea. Key words: macular rupture, internal limiting membrane, fovea-sparing ILM peeling.

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Influence of Inner Surface Defects on the Fatigue Strength of Pipe Subjected to Cyclic Internal Pressure

Journal of Pressure Vessel Technology ◽

10.1115/1.3454482 ◽

1978 ◽

Vol 100 (4) ◽

pp. 360-368

Author(s):

Y. Yazaki ◽

S. Hashirizaki ◽

S. Nishida ◽

C. Urashima

Keyword(s):

Fatigue Strength ◽

Internal Pressure ◽

Test Specimen ◽

Surface Defects ◽

Fatigue Crack Initiation ◽

Internal Surface ◽

Fatigue Tests ◽

Inner Surface ◽

Surface Notch ◽

Medium Diameter

Cyclic internal oil pressure fatigue tests were carried out on medium-diameter ERW pipes of API 5LX - X60 in an attempt to determine the influence of surface defects on the fatigue strength. Experimental factors investigated were the depth and location of internal surface notch in relation to the axis of pipe. The specimen was subjected to cyclic internal pressure, the cyclic rate being 0.3–0.5 Hz. During the test, Acoustic Emission (AE) techniques were applied to detect the fatigue crack initiation. Along with the aforementioned fatigue tests, pulsating tension fatigue tests were carried out on specimens with the same surface notches as the cyclic internal pressure fatigue test specimen.

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Continuous forming of screw-ribbed insulators

Glass and Ceramics ◽

10.1007/bf00704944 ◽

1963 ◽

Vol 20 (11) ◽

pp. 609-611

Author(s):

B. I. Gaidash

Keyword(s):

Continuous Forming

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Simulation of Temperature Field of Metal Thin Wall Parts during Laser Direct Deposition Rapid Prototyping

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.88-89.42 ◽

2011 ◽

Vol 88-89 ◽

pp. 42-45

Author(s):

Wei Zhang ◽

Shu Qin Shi

Keyword(s):

Temperature Field ◽

Element Model ◽

Temperature Cycle ◽

Thin Wall ◽

Single Track ◽

Heat Accumulation ◽

Continuous Forming ◽

Life And Death ◽

Layer Deposition ◽

Simulation And Experiment

The simulation of temperature field during laser direct metal deposition(DMD) were researched. The finite element model of single track cladding, multi-track overlapping and multi-layer deposition were established. The temperature field was simulated by ANSYS software basing on life-and-death element and cycle algorithm. Under different process parameters, the temperature and temperature gradient on the cross-section of sample were simulated during single- track scanning, multi-track overlapping and multi-layer deposition. Temperature cycle curves at different position were analyzed and were consistent with actually value. Both simulation and experiment showed that heat accumulation during continuous forming greatly affected the temperature of molten pool.

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Effect of Welding Heat on Residual Stress in Butt Welded Zone of Medium-Diameter Pipe

The Proceedings of the Materials and Mechanics Conference ◽

10.1299/jsmemm.2019.os1305 ◽

2019 ◽

Vol 2019 (0) ◽

pp. OS1305

Author(s):

Yuya ISHII ◽

Yuka MIYATA ◽

Yosuke NAKANO ◽

Yoshiteru TOYOSHIMA ◽

Nobuyoshi YANAGIDA

Keyword(s):

Residual Stress ◽

Diameter Pipe ◽

Medium Diameter

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Localization of P2X and P2Y Receptors in Dorsal Root Ganglia of the Cat

Journal of Histochemistry & Cytochemistry ◽

10.1369/jhc.4a6556.2005 ◽

2005 ◽

Vol 53 (10) ◽

pp. 1273-1282 ◽

Cited By ~ 32

Author(s):

Huai-Zhen Ruan ◽

Lori A. Birder ◽

William C. de Groat ◽

Changfeng Tai ◽

James Roppolo ◽

...

Keyword(s):

Dorsal Root Ganglia ◽

Dorsal Root ◽

Polyclonal Antibodies ◽

Small Diameter ◽

P2y Receptors ◽

Receptor Subtypes ◽

P2y Receptor ◽

Drg Neurons ◽

Double Labeling ◽

Medium Diameter

The distribution of P2X and P2Y receptor subtypes in upper lumbosacral cat dorsal root ganglia (DRG) has been investigated using immunohistochemistry. Intensity of immunoreactivity for six P2X receptors (P2X5 receptors were immuno-negative) and the three P2Y receptors examined in cat DRG was in the order of P2Y2 = P2Y4>P2X3>P2X2 = P2X7>P2X6>P2X1 = P2X4>P2Y1. P2X3, P2Y2, and P2Y4 receptor polyclonal antibodies stained 33.8%, 35.3%, and 47.6% of DRG neurons, respectively. Most P2Y2, P2X1, P2X3, P2X4, and P2X6 receptor staining was detected in small- and medium-diameter neurons. However, P2Y4, P2X2, and P2X7 staining was present in large- and small-diameter neurons. Double-labeling immunohistochemistry showed that 90.8%, 32.1%, and 2.4% of P2X3 receptor-positive neurons coexpressed IB4, CGRP, and NF200, respectively; whereas 67.4%, 41.3%, and 39.1% of P2Y4 receptor-positive neurons coexpressed IB4, CGRP, and NF200, respectively. A total of 18.8%, 16.6%, and 63.5% of P2Y2 receptor-positive neurons also stained for IB4, CGRP, and NF200, respectively. Only 30% of DRG neurons in cat were P2X3-immunoreactive compared with 90% in rat and in mouse. A further difference was the low expression of P2Y1 receptors in cat DRG neurons compared with more than 80% of the neurons in rat. Many small-diameter neurons were NF200-positive in cat, again differing from rat and mouse.

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