Search results for "Placement."
showing 10 items of 1123 documents
Inverse Analysis Used to Determine Plastic Flow and Tribological Characteristics for Deep-drawing Sheet
2014
Abstract The present paper aims to develop a simple method based on inverse analysis that allows us to determine the laws of plastic flow coefficients and the friction coefficient between the material and punch. Selecting from different types of tests, we have chosen the Hecker test, because this test requires a single form of punch, the hemispherical one. In this test, the friction between the punch and the blank-sheet is caused by the blank-sheet strains and not by the movement it makes (as in deep drawing case). Besides the friction coefficient, other parameters like hardening and strength coefficients (n and k), influence the distribution of stresses and strains in the material. Using t…
The Symmetry and Predictive Factors in Two-Stage Bilateral Hip Replacement Procedures
2021
Background: Approximately 10–25% of total hip replacement patients undergo a bilateral procedure. The purpose of this study was to compare selected parameters associated with the first and second hip arthroplasty in patients undergoing two-stage treatment due to bilateral hip osteoarthritis and establish the predictive factors for the second procedure. Methods: This study compared the data on bilateral total hip replacement surgeries conducted in the period between 2017 and 2021 (42 patients). The following parameters from the first and second procedure were compared: the prosthetic stem, head, and insert cup size
Impact of Prosthesis-Patient Mismatch after Mitral Valve Replacement
2016
Background and aim of the study: The study aim was to determine the impact of prosthesis-patient mismatch (PPM) on early and late clinical outcomes, left atrial and ventricular remodeling, late tricuspid valve regurgitation and pulmonary hypertension (PH) in patients after mitral valve replacement (MVR). Methods: A total of 46 patients (mean age 66 ± 9.3 years) with mitral valve diseases and undergoing isolated MVR was enrolled in the study. The mitral valve effective orifice area (EOA) was determined using the continuity equation and indexed for the patient’s body surface area (EOAi). PPM was defined as EOAi ≤1.2 cm2/m2. PH was defined as a systolic pulmonary artery pressure (sPAP) >40 mmH…
Preoperative evaluation before MitraClip®: present and future perspective.
2014
ABSTRACT Mitral regurgitation (MR) is the second most common heart valve disease worldwide. Currently, the management of MR is based on medical therapy (including biventricular pacing), surgery (mitral valve replacement or repair) and percutaneous therapy. However, in spite of guideline recommendations, 50% of individuals assessed in the Euro Heart Survey were not referred to surgical intervention due to comorbidities or real or perceived high risks for cardiac surgery; thus, in recent years, the focus of research has shifted to the development of percutaneous approaches to treat severe MR in order to restore valve function in a minimally invasive fashion. Among these techniques, the perc…
The Role of Endoscopy in the Treatment of Acute Traumatic Anterior Epidural Hematoma of the Cervical Spine: Case Report
1997
OBJECTIVE AND IMPORTANCE: Epidural hematoma (EDH) of the spine represents an uncommon neurosurgical disorder that sometimes requ;res emergent surgical decompressive therapy. Traumatic EDH of the cervical spine is exceedingly rare. The hematoma is usually located dorsally in the epidural space. We present one case of acute EDH located ventrally in the cervical spine. Special emphasis is placed on the role of spinal endoscopy in surgical treatment. CLINICAL PRESENTATION: After a fall from a tree, a 69-year-old man with rapidly increasing tetraparesis was referred to our institution. Plain films of the cervical spine revealed nothing abnormal. The results of computed tomography were highly sus…
Laser heterodyne displacement measuring using PLZT frequency shifter
1991
Abstract The implementation of a frequency shifter based on lead lanthanum zirconate titanate ceramic (PLZT) and a voltage-controlled λ/4 plate is described. The capabilities of these elements are demonstrated with results from a Michelson-type laser heterodyne displacement measuring interferometer with 0.01 μm accuracy and 1 Hz display update rate.
The decline and displacement of custom in early modern Spain
2019
Summary This article aims to describe the reasons for the decline of customary law in the early modern era. Confining the discussion to a limited geographical setting – the Iberian Peninsula – the arguments I used might be easily applied to other European jurisdictions. Part I presents an explanation of the predominance of custom in the medieval Spanish legal traditions. Part II describes the general features of the law in the early modern era, since they contributed – to a greater or lesser degree – to the demise of custom. Part III focuses more specifically on the theoretical and practical reasons for the decline and displacement of custom in early modern Spain. Part IV describes the cons…
On damping characteristics of frictional hysteresis in pre-sliding range
2016
Frictional hysteresis at relative motion in the pre-sliding range is considered. This effect is characterized by an elasto-plastic interaction, and that on the micro-scale, between two rubbing surfaces in contact that gives rise to nonlinear friction force. The pre-sliding friction force yields hysteresis in displacement. In this study, the damping characteristics of frictional hysteresis are analyzed. It is worth noting that we exclude the viscous damping mechanisms and focus on the pure hysteresis damping to be accounted in the friction modeling. The general properties of pre-sliding friction hysteresis are demonstrated and then compared with the limit case of discontinuous Coulomb fricti…
SELF-EXPANDABLE METAL STENT PLACEMENT FOR CLOSURE OF A LEAK AFTER TOTAL GASTRECTOMY FOR GASTRIC CANCER: REPORT ON THREE CASES AND REVIEW OF THE LITER…
2014
In the setting of the curative oncological surgery, the gastric surgery is exposed to complicated upper gastrointestinal leaks, and consequently the management of this problem has become more critically focused than was previously possible. We report here three cases of placement of a partially silicone-coated SEMS (Evolution Controlled Release Esophageal Stent System, Cook Medical, Winston-Salem, NC, USA) in patients who underwent total gastrectomy with Roux-en-Y end-to-side esophagojejunostomy for a gastric adenocarcinoma. The promising results of our report, despite the small number of patients, suggest that early stenting (through a partially silicone-coated SEMS) is a feasible alternat…
Minimum theorems for displacement and plastic strain rate histories in structural elastoplasticity
1975
The finite element method approach is used to obtain formulations of analysis problems relative to elastic-plastic structures when subjected to prescribed programmes of loads, and under the restrictive hypotheses:a) the yielding surfaces are piecewise linearized, andb) the plastic flow-laws are supposed to be of holonomic type within a single “finite” time interval. For mulations are given as linear complementarity problems and quadratic programming problems: one pair of formulations in terms of velocity and plastic multiplier rate histories, and another pair in terms of plastic multiplier rate histories only. The solutions are shown to be characterized by two minimum principles for displac…