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Search Results: 1 - 10 of 3692 matches for " Torsion Load "
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Left ventricular twist is load-dependent as shown in a large animal model with controlled cardiac load
Roman A’roch, Ulf Gustafsson, Jan Poelaert, G?ran Johansson, Michael Haney
Cardiovascular Ultrasound , 2012, DOI: 10.1186/1476-7120-10-26
Abstract: Seven anesthetised juvenile pigs were studied, using direct measurement of left ventricular pressure and volume and simultaneous transthoracic echocardiography. Transient inflation of an inferior vena cava balloon (IVCB) catheter produced controlled load reduction. First and last beats in the sequence of eight were analysed with speckle tracking (STE) during the load alteration and analysed for change in rotation/twist during controlled load alteration at same contractile status. Two pharmacological inotropic interventions were also included to examine the same hypothesis in additionally conditions of increased and decreased myocardial contractility in each animal. Paired comparisons were made for different load states using the Wilcoxon’s Signed Rank test.The inferior vena cava balloon occlusion (IVCBO) load change compared for first to last beat resulted in LV twist increase (11.67° ±2.65° vs. 16.17° ±3.56° respectively, p?<?0.004) during the load alteration and under adrenaline stimulation LV twist increase 12.56° ±5.1° vs. 16.57° ±4.6° (p?<?0.013), and though increased, didn’t reach significance in negative inotropic condition. Untwisting rate increased significantly at baseline from ?41.7°/s ±41.6°/s vs.?122.6°/s ±55.8°/s (P?<?0.039) and under adrenaline stimulation untwisting rate increased (?55.3°/s ±3.8°/s vs.?111.4°/s ±24.0°/s (p?<?0.05), but did not systematically changed in negative inotropic condition.Peak systolic LV twist and peak early diastolic untwisting rate are load dependent. Differences in LV load should be included in the interpretation when serial measures of twist are compared.Normal heart function incorporates an aspect of twisting during systole and ejection [1,2], and untwisting during relaxation and diastole [3,4]. When ventricular function is disturbed, the normal twist or wringing action can be affected. Reports have suggested importance of left ventricular rotation as an indicator of cardiac performance [5,6]. Some areas where twist ha
Post-Buckling Behavior of Laminated Composite Cylindrical Shells Subjected to Axial, Bending and Torsion Loads  [PDF]
Yengula Venkata Narayana, Jagadish Babu Gunda, Ravinder Reddy Pinninti, Markandeya Ravvala
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.34019
Abstract: In present work, post-buckling behavior of imperfect (of eigen form) laminated composite cylindrical shells with different L/D and R/t ratios subjected to axial, bending and torsion loads has been investigated by using an equilibrium path approach in the finite element analysis. The Newton-Raphson approach as well as the arc-length approach is used to ensure the correctness of the equilibrium paths up to the limit point load. Post-buckling behavior of imperfect cylindrical shells with different L/D and R/t ratios of interest is obtained and the theoretical knock-down factors are reported for the considered cylindrical shells.
Evaluation of Structural Behavior of Externally Prestressed Segmented Bridge with Shear Key under Torsion
M. A. Algorafi,A. A. A. Ali,I. Othman,M. S. Jaafar
Journal of Engineering, Project, and Production Management , 2011,
Abstract: Externally Prestressed Segmented (EPS) concrete beams are generally used in the construction of bridge structures. External Prestressed technique uses tendons that are placed completely outside the concrete section and attached to the concrete at anchorages and deviators only. Segmented bridge is a bridge built in short sections. Segmented bridge applies smart technique that is a part of an engineering management. EPS bridges are affected by combined stresses i.e., bending, shear, normal, and torsion stresses especially at the segments interface joints. Previous studies on EPS bridges did not include the effect of torsion in the load carrying capacity and other structural behavior. This paper presents an experimental investigation of the structural behavior of EPS bridged under combined bending, shear, normal, and torsion stresses. The aim of this paper is to improve the existing equation to include the effect of torsion in estimating the failure load of EPS bridge. A parametric study was carried out to investigate the effect of different external tendon layouts and different levels of torsion.
Spin, the Classical Theory  [PDF]
Richard T. Hammond
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.31001
Abstract: With the development of local gauge theories of gravitation, it became evident that intrinsic spin was an integral part of the theory. This gave spin a classical formulation that predicted the existence of a new kind of field, the torsion field. To date only one class of experiments has been developed to detect this field, a search for a long range dipole force. In this article, the torsion equations are de-coupled from the curved space of general relativity derived from basic principles using vector calculus and the theory of electromagnetism as a guide. The results are written in vector form so that they are readily available to experimentalists, paving the way for new kinds of experiments.
Natural course of ovarian torsion after untwisting: A case report with radiographic imaging  [PDF]
Dmitry Fridman, Muhammad Faisal Aslam, Neekianund Khulpateea
Open Journal of Obstetrics and Gynecology (OJOG) , 2012, DOI: 10.4236/ojog.2012.21007
Abstract: Background: Radiographic studies largely contribute to prompt diagnosis of ovarian torsion, though post-operative changes are not described and might contribute to unnecessary intervention. Case: We report a case of ovarian torsion diagnosed based on clinical presentation and radiographic findings. The detorsion was successfully performed through laparosopic access. Subsequently patient presented for elective ultrasonography and MRI which diagnosed multicystic ovarian mass, attributed to hematoma which resolved spontaneously with no intervention in 3 weeks. Conclusion: Ovarian changes after detorsion consistent with development of hematoma may be benign and resolve spontaneously.
Clinical Findings of Patients Undergone Surgery for Testicular Torsion: A 12-Year Single Center Experience in Northern Iran  [PDF]
Hamid Shafi, Amin Zarghami, Arsalan Aliramaji, Maryam Rahimi
Open Journal of Urology (OJU) , 2014, DOI: 10.4236/oju.2014.45011
Abstract:

Introduction: Testicular torsion is a surgical emergency which requires early diagnosis and prompt surgical management to avoid testicular damage. The aim of this study is to survey the clinical findings and outcome of the patients treated for testicular torsion in a university hospital in Babol, northern Iran. Methods: In this cross sectional study, a retrospective survey of all cases presenting with acute scrotum and primarily diagnosed as testicular torsion was conducted during 2001 and 2012 in Babol, northern Iran. All 103 cases were reviewed and several clinical data, including duration of symptoms and operative findings were collected. Findings: Of 103 patients who presented to the emergency department with acute scrotum, the median age of the cases was 16.0 years. Thirty four percent of the patients presented emergency unit less than 6 hours from symptom exposure. Pain (95.1%) was the major symptom in all patients. Surgery revealed that 72 (70.9%) cases were diagnosed firmly as testicular torsion that 23 patients underwent orchidectomy for a necrotic torsed testis. There were significant differences between orchiectomized versus non-orchiectomized torsion cases in affected side, symptom presentation to operation time. Conclusion: According to our results more than half of the cases presented more than in the golden time. Late presentation to hospital was the major cause of delay leading to orchidectomy in patients with testicular torsion. Greater effort in health education and direct or selfreferal to hospital may reduce this delay.

海底椭圆管道在扭矩和水压作用下的屈曲压溃研究
Buckling Collapse of Subsea Oval Pipeline Under Torsion and Hydrostatic Pressure

余建星,安思宇,李志刚,段晶辉,孙震洲,蒋梅荣,韩梦雪
- , 2018, DOI: 10.11784/tdxbz201705033
Abstract: 在实际工程中海底管道往往具有一定的椭圆度, 椭圆管道受到扭矩作用会影响其极限承载力.对于服役前受到扭矩作用的等壁厚椭圆管道, 通过理论推导得到了其在弹性阶段的位移方程, 并建立数值模型对理论方法进行了验证.利用有限元中的弧长法对椭圆管道在服役中的塑性屈曲压溃进行了数值模拟, 研究了壁厚、一致椭圆度、外径等敏感性因素对其压溃压力的影响.同时分析了椭圆管道在服役过程中受到扭矩作用后的屈曲压溃特性.结果表明, 尺寸参数及扭矩加载路径会对管道极限承载力产生明显影响, 分析结果可为实际工程应用提供参考.
It is common that subsea pipelines have a certain ovality degree in practical engineering. The ultimate bearing capacity of oval pipelines would be affected by torsion. For oval pipelines with equal thickness subjected to torsion before service,their displacement equation in the elastic stage is obtained by theoretical reduction which is verified by numerical simulation. The collapse of pipelines in the plastic stage during service is researched by FE arc-length method,and several influence factors of collapse pressure,including thickness,uniform ovality,outside diameter etc,are studied. At the same time,the buckling collapse of oval pipelines under torsion during service is analyzed. It shows that dimension parameters and torsion load-path would have remarkable effects on the ultimate bearing capacity of pipelines,which could provide reference for practical engineering
Atypical presentation and localization of granulosa cell tumor—A case report and review of the literature  [PDF]
Evangelos Grigoriou Sakkas, Dario Bucella, Alexandre Roland De Wind, Claudia Stanciu, Frederic Buxant
Open Journal of Obstetrics and Gynecology (OJOG) , 2012, DOI: 10.4236/ojog.2012.22031
Abstract: Introduction: Extraovarian granulosa cell tumor (GCT) is a very uncommon tumor, assumed to arise from the ectopic gonadal tissue along the embryonal route of the genital ridge. Case report: We report the case of a 25 year-old woman who was presented at the emergency unit with a severe abdominal pain focused on the left iliac fossa. The patient had delivered normally 2 months before. An ovarian mass of 79 × 67 × 89 mm was shown in vaginal ultrasound as well as at the abdominal scan. Exploratory laparoscopy was performed and a torsion of the fallopian tube and an hemato-salpinges was visualized. Re-vascularisation was not achieved and a left salpingectomy took place. The immuno-histopathology report revealed an extra-ovarian GCT deriving from the fimbriae of the tube. Follow-up surgery was discussed. The case is presented for its rarity.
An Unusual Presentation of Pelvic Pain: Torsion of Ovarian Endometroid Adenocarcinoma
Firat BEKTAS,Cem OKTAY
Turkish Journal of Emergency Medicine , 2009,
Abstract: Letter to the Edit r
TORSION OF TESTIS
Irfan Akhtar
The Professional Medical Journal , 1995,
Abstract: A retrospective study of thirty two patients presenting to Emergency department of Rawalpindi General Hospitalwith acute scrotal pain, all being subjected to surgery. Seventeen (54%) were found to have gangrenous testiswith mean time of presentation 9 hours. Nine (28%) patients could be salvaged with bilateral fixation. Seven(22%) were found to have torsion of appendix testis with mean time of presentation being 18 hours. Torsionin undescended testis was encountered in seven (22%) patients. Six(19%) patients had negative explorationsand all were above 25 years of age.
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