• Title/Summary/Keyword: torsion

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Testicular torsion in the inguinal region in an extremely low birth weight infant

  • Jung, Yu-Jin;Chung, Jae-Min
    • Clinical and Experimental Pediatrics
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    • v.53 no.9
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    • pp.852-854
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    • 2010
  • Testicular torsion is rare in newborn infants. However, its frequency has increased, most of which are reported in full-term infants. We diagnosed and treated testicular torsion in an extremely low birth weight infant (ELBWI). A $2{\times}2cm$ red mass was palpable in the left groin of a 24-week-old, 745 g, male newborn at 23 days of age. Left testicular torsion was diagnosed, and emergent orchiopexy was performed. Careful physical examination is needed in cases suspicious of testicular torsion in ELBWIs with cryptorchidism. Moreover, early diagnosis and emergent exploration are necessary to prevent complications such as the risk of anorchia.

Effect of Heat Treatment on Torsion Characteristics of High Nitrogen Steel Wire for Overhead Conductors (송전선용 고질소강선의 비틀림 특성에 미치는 열처리의 영향)

  • 김정훈;김봉서;박수동;김병걸;이희웅
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.2
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    • pp.190-195
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    • 2004
  • The effect of heat treatment on torsion characteristics of high nitrogen steel wire has been studied by torsion test, tensile test, specific resistivity, X-ray diffraction and scanning electron microscopy. After heat treatment at 600∼$700^{\circ}C$, torsion cycle was increased with increasing temperature. Especially, in case of high nitrogen steel wire heat teated at $650^{\circ}C$, torsion cycle was sharply increased. It is estimated that cold worked high nitrogen steel wire started to recrystallize and phase transform at 64$0^{\circ}C$ in air atmosphere.

DISCRETE TORSION AND NUMERICAL DIFFERENTIATION OF BINORMAL VECTOR FIELD OF A SPACE CURVE

  • Jeon, Myung-Jin
    • The Pure and Applied Mathematics
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    • v.12 no.4 s.30
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    • pp.275-287
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    • 2005
  • Geometric invariants are basic tools for geometric processing and computer vision. In this paper, we give a linear approximation for the differentiation of the binormal vector field of a space curve by using the forward and backward differences of discrete binormal vectors. Two kind of discrete torsion, say, back-ward torsion $T_b$ and forward torsion $T_f$ can be defined by the dot product of the (backward and forward) discrete differentiation of binormal vectors that are linear approximations of torsion. Using Frenet formula and Taylor series expansion, we give error estimations for the discrete torsions. We also give numerical tests for a curve. Notably the average of $T_b$ and $T_f$ looks more stable in errors.

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Strength of prestressed concrete beams in torsion

  • Karayannis, Chris G.;Chalioris, Constantin E.
    • Structural Engineering and Mechanics
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    • v.10 no.2
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    • pp.165-180
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    • 2000
  • An analytical model with tension softening for the prediction of the capacity of prestressed concrete beams under pure torsion and under torsion combined with shear and flexure is introduced. The proposed approach employs bilinear stress-strain relationship with post cracking tension softening branch for the concrete in tension and special failure criteria for biaxial stress states. Further, for the solution of the governing equations a special numerical scheme is adopted which can be applied to elements with practically any cross-section since it utilizes a numerical mapping. The proposed method is mainly applied to plain prestressed concrete elements, but is also applicable to prestressed concrete beams with light transverse reinforcement. The aim of the present work is twofold; first, the validation of the approach by comparison between experimental results and analytical predictions and second, a parametrical study of the influence of concentric and eccentric prestressing on the torsional capacity of concrete elements and the interaction between torsion and shear for various levels of prestressing. The results of this investigation presented in the form of interaction curves, are compared to experimental results and code provisions.

Analysis of Bending and Rotation Phenomenon of Torsion Bar During Press-fitting Process for EPS Angle Sensors (EPS 각도센서용 토션 바의 압입공정의 휨과 회전현상 분석)

  • H. Lee;S.H. Lee;T.H. Jeon;I.-K. Chung
    • Transactions of Materials Processing
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    • v.32 no.6
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    • pp.376-383
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    • 2023
  • The torsion bar, which is a steering torque sensor, is mounted between the steering pinion and the input shaft in the IPA(input pinion assembly). Accurate torque measurement is important to improve the sense of operation, and the straightness of the torsion bar can affect torque measurement. In this study, the amount of bending was measured and the exact shape was analyzed regarding the bending phenomenon in the press-fitting process for torsion bars. The effect of alignment error was analyzed through finite element forming analysis. Process data analysis was conducted for the double-end press fit model. If there is an alignment error of about 10% of the serration tooth height, the indentation load is reduced by about 10%. If there is an alignment error, the torsion bar is rotated.

Multilayered viscoelastic beam loaded in torsion under strain-path control: A delamination analysis

  • Victor I. Rizov
    • Advances in materials Research
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    • v.13 no.2
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    • pp.87-102
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    • 2024
  • This paper is focused on the delamination analysis of a multilayered beam structure loaded in torsion under strain-path control. The beam under consideration has a rectangular cross-section. The layers of the beam are made of different viscoelastic materials which exhibit continuous inhomogeneity in longitudinal direction. Since the delamination is located inside the beam structure, the torsion moments in the two crack arms are obtained by modeling the beam as an internally static undetermined structure. The strain energy stored in the beam is analyzed in order to derive the strain energy release rate (SERR). Since the delamination is located inside the beam, the delamination has two tips. Thus, solutions of the SERR are obtained for both tips. The solutions are verified by analyzing the beam compliance. Delamination analysis with bending-torsion coupling is also performed. The solutions derived are timedependent due to two factors. First, the beam has viscoelastic behavior and, second, the angle of twist of the beam-free end induced by the external torsion moment changes with time according to a law that is fixed in advance.

ON FREE AND TORSION-FREE AUTOMATA

  • Park, Chin-Hong
    • Journal of applied mathematics & informatics
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    • v.1 no.1
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    • pp.75-78
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    • 1994
  • In this paper we define free torsion-free and torsion-free completely on an automaton. We prove some properties of them which are important

MAYER-VIETORIS SEQUENCE AND TORSION THEORY

  • Payrovi, Sh.
    • Bulletin of the Korean Mathematical Society
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    • v.37 no.3
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    • pp.419-428
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    • 2000
  • This work presents a new construction of Mayer-Vietoris sequence using techniques from torsion theory and including the classical case as an example.

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The effects of berberine on ischemia-reperfusion injuries in an experimental model of ovarian torsion

  • Filiz Yilmaz;Orkun Ilgen;Alper Mankan;Bayram Yilmaz;Sefa Kurt
    • Clinical and Experimental Reproductive Medicine
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    • v.50 no.4
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    • pp.292-298
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    • 2023
  • Objective: Ovarian torsion is a gynecological disorder that causes ischemia-reperfusion injuries in the ovary. Our study investigated berberine's short- and long-term effects on ovarian ischemia-reperfusion injuries. Methods: This study included 28 Wistar albino female rats weighing 180 to 220 g, which were divided into four groups: sham (S), torsion/detorsion (T/D), torsion/ detorsion+single dose berberine (T/D+Bb), and torsion/detorsion+15 days berberine (T/D+15Bb). The torsion and detorsion model was applied in all non-sham groups. In the T/D+Bb group, a single dose of berberine was administered, while in the T/D+15Bb group, berberine was administered over a period of 15 days. After the rats were euthanized, their ovaries were excised. The left ovaries were used for histopathologic evaluation, which included ovarian injury scoring and follicle count, while the right ovaries were used for biochemical analyses (tissue transforming growth factor-β [TGF-β] and alpha-smooth muscle actin [α-SMA] levels). Results: The histopathologic evaluation scores for the ovaries were significantly lower in the T/D+B group (p<0.05) and the T/D+15B group (p<0.005) than in the T/D group. The follicle counts in the T/D group were lower than those in both the sham and treated groups (p<0.005). The TGF-β levels were significantly lower in the T/D+15B group (p<0.005), whereas the α-SMA levels did not show a significant difference. Conclusion: Both short- and long-term berberine use could potentially have therapeutic effects on ovarian torsion. Long-term berberine use exhibited anti-inflammatory effects by reducing TGF-β levels, thereby preventing ischemia-reperfusion injuries. Therefore, we suggest that long-term berberine use could be beneficial for ovarian torsion.

Concurrent Torsion of the Caudate Liver Lobe and Spleen in a German Shepherd Dog

  • Seong-won An;Seung-Min Hwang;Il-Gwon Jung;Sang-Kwon Lee;Young-Sam Kwon
    • Journal of Veterinary Clinics
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    • v.41 no.1
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    • pp.30-36
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    • 2024
  • A 3-year-old, 20.6 kg, neutered male German Shepherd dog was referred to Kyungpook National University Veterinary Medicine Teaching Hospital. Clinical examination revealed chronic diarrhea for 6 weeks and a non-tender, distended abdomen without lethargy, anorexia, and vomiting. Diarrhea was watery and had a waxing and waning course despite symptomatic treatment. A complete blood count identified mild leukocytosis and mild anemia. Serum biochemistry analysis showed elevated alanine aminotransferase and aspartate aminotransferase levels, and mild hypoalbuminemia. Abdominal ultrasound examination revealed mixed echogenicity with absent blood flow at the caudate process of the caudate liver lobe and a small amount of ascites. Computed tomography revealed torsion of the caudate process of the caudate liver lobe and spleen and gas dilatation of the intestine. After establishing a diagnosis of organ torsion on imaging, we deemed the condition an emergency and immediately performed surgery. Given that laparotomy confirmed organ torsion, liver lobectomy, total splenectomy, and prophylactic gastropexy were conducted. The patient was discharged 11 days after surgery without complications. In general, liver lobe torsion and splenic torsion are uncommon in dogs and present with nonspecific clinical signs, such as abdominal pain, lethargy, anorexia, and vomiting. In the current case, torsion of the caudate liver lobe and spleen occurred without other clinical signs except for a distended abdomen. Moreover, no reports in dogs have demonstrated the simultaneous occurrence of both diseases.