Search results for "Fracture"

Microstructure, porosity and mineralogy around fractures in Olkiluoto bedrock

2012

3D distributions of minerals and porosities were determined for rock-core samples that included water-conducting fractures. The analysis of these samples was performed using conventional petrography methods, C-14-PMMA porosity analysis and X-ray tomography. It seems that the properties of rock around a water-conducting fracture depend on so many uncorrelated factors that no clear pattern emerged even for rock samples with a given type of fracture. We can conclude, however, that the present combination of methods can be used to infer novel structural information about alteration zones adjacent to fracture surfaces.

Physical activity after a hip fracture : effect of a multicomponent home-based rehabilitation program - a secondary analysis of a randomized controll…

2017

Objectives To investigate the effect of a yearlong multicomponent rehabilitation program on the level of physical activity (PA) and the maintenance of the level of PA over 1-year follow-up among older people recovering from a recent hip fracture. Design Secondary analysis of a randomized, controlled, parallel-group trial. Setting Home-based rehabilitation; measurements in university laboratory. Participants Community-dwelling people (N=81) aged ≥60 years recovering from a hip fracture. Participants were randomly assigned to an intervention (n=40) or a control (n=41) group, on average, 42±23 days after discharge from the hospital. Intervention A yearlong intervention included evaluation and …

Kvalitet på elektronisk sykepleiedokumentasjon hos pasienter med hoftebrudd og helsetjenesteassosiert infeksjon

2019

Masteroppgave klinisk helsevitenskap ME520 - Universitetet i Agder 2019 Project background: Approximately 9000 patients with hip fractures are annually admitted to hospitals (Folkehelseinstituttet, 2016). About 50000 patients receive an annual health-related infectionthat cangive more number of bed nightsand an increasedrisk of mortality. Good infection control procedurescan prevent some of the health related infections (Helse-og omsorgsdepartementet, 2008b). Nursing for these patients consists of a pre-and a postoperative periodwhere observations of signs of complications are important(Knutstad, 2013). Research shows that nursing documentation in several cases is poor, both in relation to …

Balance confidence and functional balance are associated with physical disability after hip fracture

2012

Background. This cross-sectional study investigated the associations between balance confidence, functional balance, and physical disability among older people after hip fracture. Material and methods. The study utilizes baseline data of two randomized controlled trials (ISRCTN34271567 and ISRCTN53680197). The participants were 159 community-dwelling over 60-year-old people. Health, fracture status, the date and type of surgery, and contraindications for participation were assessed in a clinical examination. Balance confidence was assessed by the Activities-specific Balance Confidence Scale (ABC) and functional balance by the Berg Balance Scale. Physical disability was assessed by a questio…

Experimentelle Bestimmung der Gleitreibungskräfte beim Einschlagen von Oberschenkelmarknägeln

1990

No data have published concerning the procedure of driving in intramedullary nails. An extensive experimental device consisting of a contact-free distance measurement, a dynamograph connected to strain gages and an accelerometer now enabled this investigation. Among other things we determined the range of sliding friction for each stroke at different levels of nail-progression. Depending of the depth of nail-progression forces between 200 N und 400 N were measured. When the nail is stuck these values rise to over 1000 N. The sliding-process lasted between 10 ms and 20 ms. Knowledge of these data is of major importance for improvement of surgical technique and possible development of mechani…

Simulation of Fatigue Delamination Growth in Composites with Different Mode Mixtures

2007

A numerical model, obtained by implementing a cyclic damage model in the framework of an interface element, is here proposed to reproduce the crack growth in laminated composites subjected to cyclically repeated loads. This model, which differs from the few studies in the literature on the topic, applies not only to single fracture modes but also to mixed modes, and to constant or variable crack growth rates. The applied load (in terms of force or displacement) is assumed to oscillate between a minimum and a maximum constant value. The Paris curve can be reproduced with accuracy once some parameters in the numerical model are tuned with experiments. These parameters are preliminarily found…

Friction of Shear-Fracture Zones

2017

A shear fracture of brittle solids under compression undergoes a substantial evolution from the initial microcracking to a fully formed powder-filled shear zone. Experiments covering the entire process are relatively easy to conduct, but they are very difficult to investigate in detail. Numerically, the large strain limit has remained a challenge. An efficient simulation model and a custom-made experimental device are employed to test to what extent a shear fracture alone is sufficient to drive material to spontaneous selflubrication. A “weak shear zone” is an important concept in geology, and a large number of explanations, specific for tectonic conditions, have been proposed. We demonstra…

Hierarchical BEM for dynamic analysis of anisotropic 3-D cracked solids

2011

A new mixed-mode fracture criterion for large-scale lattice models

2014

Abstract. Reasonable fracture criteria are crucial for the modeling of dynamic failure in computational lattice models. Successful criteria exist for experiments on the micro- and on the mesoscale, which are based on the stress that a bond experiences. In this paper, we test the applicability of these failure criteria to large-scale models, where gravity plays an important role in addition to the externally applied deformation. Brittle structures, resulting from these criteria, do not resemble the outcome predicted by fracture mechanics and by geological observations. For this reason we derive an elliptical fracture criterion, which is based on the strain energy stored in a bond. Simulation…

New Comers, fiducia e frammentazione sociale nelle comunità a forte differenziazione culturale

2010

L’articolo ha come base empirica uno studio di comunità svolto in un microcosmo siciliano, Mazara del Vallo, assunto come paradigma delle società a forte differenziazione culturale, in cui la pluridecennale convivenza tradizionale tra autoctoni e comunità tunisina è stata investita dalle nuove ondate di immigrati dell’est europa. La ricerca qualitativa effettuata con storie di vita e interviste in profondità, somministrate alla popolazione autoctona, agli immigrati tunisini di prima e seconda generazione e ai “nuovi” immigrati ha evidenziato non solo inedite rappresentazioni di frammentazione sociale, sentimento di fiducia, marginalizzazione, ma anche la ridefinizione di pratiche culturali …