Search results for " Torsion."

Hemodynamic effects of experimental testicular torsion.

1987

Experimental testicular torsion must be used for certain studies of clinical relevance, but most experimental models either do not provide hemodynamic alteration comparable to the clinical situation or cannot guarantee reproducibility. Using a rat model arterial perfusion and hemorrhagic infarction were correlated to the degree of both intra- and extravaginal testicular torsion. Arterial inflow was measured sequentially with radiolabelled microspheres, hemorrhagic infarction was judged by the increase of testicular weight. Maximal hemorrhagic infarction and reproducible values were found when the spermatic cord was twisted together with the tunica vaginalis for 360 degrees-540 degrees.

Quantum gravity with torsion and non-metricity

2015

We study the renormalization of theories of gravity with an arbitrary (torsionful and non-metric) connection. The class of actions we consider is of the Palatini type, including the most general terms with up to two derivatives of the metric, but no derivatives of the connection. It contains 19 independent parameters. We calculate the one loop beta functions of these parameters and find their fixed points. The Holst subspace is discussed in some detail and found not to be stable under renormalization. Some possible implications for ultraviolet and infrared gravity are discussed.

Confronto tra metodologie di varo a spinta di ponti curvi a cassone in c.a.p. ed effetti della torsione primaria e secondaria

2014

TORSIONAL STRESS CONCENTRATIONS IN SHAFTS: FROM ELECTRICAL ANALOGIES TO NUMERICAL METHODS

2013

This paper presents the historical development of methods used for the study of torsional stresses in shafts. In particular the paper covers both analog methods, in particular those based on electrical analogies proposed since about 1925, and numerical methods, in particular finite difference methods (FDM), finite element methods (FEM) and boundary elements (BEM).

On the history of torsional stress concentrations in shafts: From electrical analogies to numerical methods

2014

This article proposes a retrospective on experimental and numerical methods developed throughout the past century to solve the torsion problem in shafts, with particular emphasis on the determination of shear stress concentration factors in discontinuities of typical use in shaft design. This article, in particular, presents the theory and related solutions distinguishing between two classes of geometries: shafts with constant cross section and axisymmetric shafts with variable diameter. Emphasis is given to approaches based on physical analog methods and, in particular, those based on electrical analogies proposed since about 1925. Experimental methods based on structural physical models …

Torsional shear strength and elastic properties of adhesively bonded glass-to-steel components

2020

Nowadays glass is widely used in building applications and coupled to steel through adhesive joining. Reliable mechanical characterization of these joints is necessary to design and predict the final structure performance.In this framework, the aim of this paper is to measure the pure shear strength and elastic modulus for design and modelling of adhesive joined glass-to-steel structures.Torsional shear strength and elastic properties of an adhesively bonded glass-to-steel component were measured on several joined steel-to-steel and steel-to-glass samples.An epoxy resin-based adhesive was used as joining material for AISI304 steel and soda-lime glass.The same steel and adhesive were used to…

Excision of ectopic adrenocortical tissue during laparoscopy for isolated tubal torsion

2017

Ectopic adrenal tissue is an occasional finding during surgery procedures. These remnants are usually found near the primary gland or along the course of gonadal vessels consistently with embryologic development. The appearance is of a small but distinct, soft, round, yellow nodule and only cortical adrenal tissue is normally observed. We report a case of an emergency laparoscopic salpingostomy for isolated tubal torsion with excision of EAT, incidentally found in left ovarian pedicle, followed by postoperative resumption of regular menses and regression of hirsutism. Although intraoperative research of ectopic adrenal tissue is not necessary its removal is indicated in case of incidental f…

Laparoscopic management of an isolated left fallopian tube torsion due to twisted Morgagni hydatid in a pre-menarcheal girl.

2014

Isolated torsion of fallopian tube, meanwhile uncommon, should be considered in diagnosis of pelvic and lower abdominal pain. US investigation is an useful diagnostic tool. A prompt diagnosis could avoid salpingectomy and preserve fertility. Laparoscopy, as the first approach, should be preferred. We report a case of isolated tubal torsion occurring in a premenarcheal girl successfully managed by laparoscopy.

On the influence of curvature and torsion on turbulence in helically coiled pipes

2014

Turbulent flow and heat transfer in helically coiled pipes at Retau=400 was investigated by DNS using finite volume grids with up to 2.36×10E7 nodes. Two curvatures (0.1 and 0.3) and two torsions (0 and 0.3) were considered. The flow was fully developed hydrodynamically and thermally. The central discretization scheme was adopted for diffusion and advection terms, and the second order backward Euler scheme for time advancement. The grid spacing in wall units was ~3 radially, 7.5 circumferentially and 20 axially. The time step was equal to one viscous wall unit and simulations were typically protracted for 8000 time steps, the last 4000 of which were used to compute statistics. The results s…

The warping torsion as a sequence of infinite bending problems

2014

[EN] In the present article, a methodology for teaching modeling problem of mixed torsion for thin-walled open sections. The mathematical analogy of warped twist as a problem of Euler-Bernoulli beams is exploited. In fact, the paper proposes to represent the warped torsion differential equation as a perturbation of the pure torsion or also called the Saint-Venant theory. Thus, it is demonstrated that under certain conditions related to the value of the torsional slenderness the response of a beam is the addition of infinite pure warped problems, that is, infinite bending problems, according to the analogy. We call this the asymptotic torsion analogy.