Search results for "FRACTURE"

Tracer migration in crystalline rock : application to geological barriers of nuclear waste storage

2016

This work deals with transport of radionuclides in the geosphere. The subject is investigated through characterisation of water conducting fractures, determining of rock transport properties and development of new methods for characterising geological samples. Here, as is often the case, radionuclide transport is investigated indirectly by characterising the structures, where the transport takes place, and directly by measuring transport properties in the gas phase. First water conducting fractures of three different types and the rock matrix surrounding them were analysed through rock samples from Olkiluoto. The analysis was done using X-ray tomography, the 14C-PMMA autoradiography techniq…

Microsurgery and external fixation in orthoplastic reconstruction of tibial injuries.

2019

"Orthoplastics" is a relatively new approach to lower limb reconstruction, where an integration of both plastic and orthopedic expertise is required, together with the availability of well-equipped facilities. Acute shortening and long-term frames for lengthening are generally considered alternatives to length preservation and soft tissue microsurgical reconstruction, but an integration of external fixation and reconstructive microsurgery is gaining an increasing role with refinements of joint approaches.Data on sixteen patients who underwent microsurgical lower limb reconstruction and external fixation with an orthoplastic approach, following acute or chronic tibial injury, were retrospect…

Osteoporosis from etiopathogenesis to rehabilitation

2015

Stochastic fracture analysis of systems with moving material

2015

This paper considers the probability of fracture in a system in which a material travels supported by rollers. The moving material is subjected to longitudinal tension for which deterministic and stochastic models are studied. In the stochastic model, the tension is described by a multi-dimensional Ornstein-Uhlenbeck process. The material is assumed to have initial cracks perpendicular to the travelling direction, and a stochastic counting process describes the occurrence of cracks in the longitudinal direction of the material. The material is modelled as isotropic and elastic, and LEFM is applied. For a general counting process, when there is no fluctuation in tension, the reliability of t…

Peri-Implant Distal Radius Fracture: Proposal of a New Classification

2022

A peri-implant fracture near the volar plate of the distal radius represents a rarity and can be associated with a mechanical failure of the devices. A literature review was conducted including all fractures that occurred around a volar wrist plate, which could be associated with an ulna fracture. All articles published until December 2021 were considered according to the guidelines presented in the PRISMA Statement. The search was conducted with the PubMed electronic database, Cochrane Database of Systematic Reviews, Medline, Embase, and Google Scholar. Only nine cases of these fractures were reported in the literature. The causes could be due to delayed union/non-union of the old fracture…

BEM analysis of a piezoelectric structural health monitoring system for delamination detection

2013

In the present work a piezoelectric based structural health monitoring (SHM) system is analyzed with the aim of assessing the ability of the piezoelectric patch to detect both edge and embedded delaminations proper of flange-skin composite laminated structures. he boundary element model is developed for piezoelectric solids and is implemented by taking advantage of the multidomain technique to model laminated and cracked configurations. A non-linear spring model interface is then implemented in conjunction with an iterative procedure allowing for the simulation of the finite stiffness of the bonding layers as well as of the non-penetration condition of the delamination surfaces. he dynamic …

Fracture and fatigue of titanium narrow dental implants: New trends in order to improve the mechanical response

2019

Sixty-four fractured commercially pure titanium (cp-Ti) narrow dental implants (NDIs) with similar macrogeometry and connection designs were studied after different implantation times in humans in order to determine their reliability and to evaluate the causes of the fracture. These NDIs were compared with other similar implants, made with alloyed titanium with 15% Zr and with 12% strained titanium. Original implants were tested under static and fatigue conditions, simulating the tri-axial loads in the mouth by means of a Bionix hydraulic test machine. Fractography was studied using field-emission scanning electron microscopy (FSEM). The results showed that cp-Ti NDI exhibits low strength f…

Preoperativ oppvarming av pasienter med hoftebrudd : Kan preoperativ oppvarming med varmluftsteppe redusere intraoperativt temperaturfall hos pasient…

2018

Masteroppgave spesialsykepleie ME519 – Universitetet i Agder 2018 Background: Hip fractures are a common cause of hospitalization and are linked with high morbidity and mortality rates. It is therefore important to optimize every aspect of their treatment to minimize complications. The Nurse Anesthetist plays an important role in preventing complications related to both surgery and anesthesia. Purpose: The aim of this project is to evaluate the quality of the current procedure for preoperative prevention of hypothermia in our hospital. We wanted to investigate if this procedure for preventing hypothermia is as effective as preoperative warming with a forcedair system in hip fracture patient…

Association between low-frequency ultrasound and hip fractures - comparison with DXA-based BMD

2014

Background: New methods for diagnosing osteoporosis and evaluating fracture risk are being developed. We aim to study the association between low-frequency (LF) axial transmission ultrasound and hip fracture risk in a population-based sample of older women. Methods: The study population consisted of 490 community-dwelling women (78 – 82 years). Ultrasound velocity (V LF ) at mid-tibia was measured in 2006 using a low-frequency scanning axial transmission device. Bone mineral density (BMD) at proximal femur measured using dual-energy x-ray absorptiometry (DXA) was used as the reference method. The fracture history of the participants was collected from December 1997 until the end of 2010. Li…

Dynamics of hydrofracturing and permeability evolution in layered reservoirs

2015

International audience; A coupled hydro-mechanical model is presented to model fluid driven fracturing in layered porous rocks. In the model the solid elastic continuum is described by a discrete element approach coupled with a fluid continuum grid that is used to solve Darcy based pressure diffusion. The model assumes poro-elasto-plastic effects and yields real time dynamic aspects of the fracturing and effective stress evolution under the influence of excess fluid pressure gradients. We show that the formation and propagation of hydrofractures are sensitive to mechanical and tectonic conditions of the system. In cases where elevated fluid pressure is the sole driving agent in a stable tec…