Academic literature on the topic 'Ring slitting method'

During polymerization, dental composites develop residual stresses that may compromise the marginal integrity and properties of the restorative. The objective of this study was to use the thin-walled ring-slitting method to measure and compare residual stresses. The hypotheses to be tested were that composites would generate different levels of residual stress based on their specific formulations and slitting times. Rings made from composites (Z100, Herculite, and Heliomolar) were cut at different times (10 min, 1 and 24 hrs) after being light-cured, and stress was measured. Residual stress was higher at the earlier cutting times, except for Heliomolar (α < 0.05). For the 10-minute and one-hour cutting groups, stress followed this order: Z100 > Herculite > Heliomolar. Early slitting was better to capture residual stress, and the thin-walled rings showed higher values than thick-walled rings and were better able to discriminate residual stress in composites.

<p class="abstract"><strong>Background:</strong> <span lang="EN-GB">The lack of anterior support for the graft frequently leads to graft failure if an underlay method is used whereas anterior blunting is a complication of overlay techniques in the anteriorly located tympanic membrane perforations</span><span lang="EN-IN">. The objective of the study was </span><span lang="EN-GB">to evaluate the correct surgical technique for the reconstruction of anterior tympanic membrane perforation.</span></p><p class="abstract"><strong>Methods:</strong> <span lang="EN-GB">Our prospective study was conducted from January 2011 to December 2013. This study included 39 patients of either sex, 17-56 years of age groups, at Kamineni Institute of Medical Sciences Narketpally, Nalgonda district, Telangana state. Our surgical experience with a) Simplified underlay technique-in small perforations having healthy remnant in10 patients. b) Button hole and slitting the graft- in thin atrophic ring anteriorly in 25 patients. c) Gerlach’ quilting procedure- in inadequate anterior rim in 3 patients and d) Kerr flap-in only anterior rim annulus in 1 patient</span><span lang="EN-IN">. </span></p><p class="abstract"><strong>Results:</strong> <span lang="EN-GB">All these methods gave 91.96% closure rate, a mean auditory threshold gain of 8.5 dB was achieved at the frequencies tested</span><span lang="EN-IN">. </span></p><p class="abstract"><strong>Conclusions:</strong> <span lang="EN-GB">Here we describe and promote the various techniques of placing grafts in anterior perforations of tympanic membrane, thereby attaining the aforementioned benefits and reducing the incidence of complications</span><span lang="EN-IN">.</span></p>

Tantalum refractory liners were explosively clad into cylindrical pressure vessels, some of which had been previously autofrettaged. Using explosive cladding, the refractory liner formed a metallurgical bond with the steel of the pressure vessel at a cost of induced strain. Two techniques were employed to determine the residual stress state of the clad steel cylinders: neutron diffraction and mechanical slitting. Neutron diffraction is typically nondestructive; however, due to attenuation along the beam path, the cylinders had to be sectioned into rings that were nominally 25 mm thick. Slitting is a destructive method, requiring the sectioning of the cylindrical samples. Both techniques provided triaxial stress data and useful information on the effects of explosive cladding. The stress profiles in the hoop and radial directions were similar for an autofrettaged, nonclad vessel and a clad, nonautofrettaged vessel. The stress profiles in the axial direction appeared to be different. Further, the data suggested that residual stresses from the autofrettage and explosive cladding processes were not additive, in part due to evidence of reverse yielding. The residual stress data are presented, compared and discussed.

This thesis is dealing with the issue of residual stress present in the wall of a polymer pipe and the influence on its lifetime. Experimental data obtained by the ring slitting method are evaluated and the tangential residual stress in the wall of polypropylene pipe is determined. The evaluation is carried out using a new methodology based on the curved beam theory. The method is verified using numerical simulation. 3D numerical model is used to verify the behavior of the pipe, when there are both tangential and axial residual stresses present in the pipe wall, because the presence of axial stress causes a rise in the magnitude of tangential residual stress. A correction of the tangential stress values corresponding to the pipe length is then proposed. It is shown, that the distribution of the tangential residual stress does not depend significantly on the dimensions or ma-terial of the extruded pipe and a general equation is proposed to describe the distribution. This general distribution is then involved in the calculations of the pipe lifetime that are carried out using a method based on the linear elastic fracture mechanics. A significantly lower lifetimes are obtained when taking the residual stress into account.