Search results for " Strengthening"
showing 10 items of 36 documents
Flexural behaviour of calcarenite masonry walls reinforced with FRP sheets
2015
The use of fiber-reinforced polymers (FRP) for structural strengthening has become increasingly popular in recent years. Several applications of FRP have been proposed and applied, depending on the target of the technique, kind and/or material of the structural member. In particular, because of their great tensile strength, FRP materials are commonly used to enhance the out-of-plane behaviour of masonry walls, allowing to increase their strength, ductility and improving safety against overturning. For these reasons, FRP laminates are often applied in vulnerable ancient buildings in seismic areas to reinforce façades and walls with poor structural features. However, some issues arise when ad…
Analysis of bond strength between a nylon reinforcement structure and dental resins
2021
Made available in DSpace on 2021-06-25T10:30:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-01 Background: Nylon is a polymer that its use to reinforce dental resins has shown positive results such as increased flexural strength. The aim of this study was to evaluate the bond strength between dental resins and a nylon reinforcement. Material and Methods: Forty cylindrical nylon blocks with 13 x 23 mm with 0.5% by volume of silica and 40 without were made. Half of the samples of each nylon composition were sandblasted with aluminum oxide (50µm) for 3 s (2.8 bar pressure, distance: 20 mm, incidence angle: 90o). On the nylon blocks, cylinders of chemically activated acrylic resin…
RC beams retrofitted by FRP oriented in any direction: Influence of the effectiveness factors
2022
Shear strength of FRP-retrofitted RC beams is usually influenced by different brittle failure modes characterizing the collapse of the FRP reinforcement. The most significant analytical models for assessing the shear strength of FRP-retrofitted RC beams reflect the effect of brittle failure through an effectiveness factor “R”, which reduces the ultimate tensile strength of FRP. The brittle collapse of FRP reinforcement often leads to a lower shear contribution by steel stirrups due to hindering of the yielding of all stirrups involved by critical cracking. Some analytical models consider this phenomenon introducing a further effectiveness factor “r”, which reduces the yielding strength of s…
Elective surgery system strengthening: development, measurement, and validation of the surgical preparedness index across 1632 hospitals in 119 count…
2022
© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: The 2015 Lancet Commission on global surgery identified surgery and anaesthesia as indispensable parts of holistic health-care systems. However, COVID-19 exposed the fragility of planned surgical services around the world, which have also been neglected in pandemic recovery planning. This study aimed to develop and validate a novel index to support local elective surgical system strengthening and address growing backlogs. Methods: First, we performed an international consultation through a four-stage consensus process to develop a multidomain index for hospital-level assess…
Influence of Cross-Section Shape and FRP Reinforcement Layout on Shear Capacity of Strengthened RC Beams
2022
The evaluation of the shear capacity of an FRP-strengthened reinforced-concrete beam is challenging due to the complex interaction between different contributions provided by the concrete, steel stirrup and FRP reinforcement. The shape of the beam and the FRP inclination can have paramount importance that is not often recognized by the models that are suggested by codes. The interaction among different resisting mechanisms has a significant effect on the shear capacity of beams, since it can cause a reduction in the efficiency of some resisting mechanisms. A comparative study of the performance in the shear resistance assessment provided by three models with six different effectiveness fact…
Relation between grain size and hydrogen diffusion coefficient in an industrial Pd–23% Ag alloy
1999
Abstract The diffusion mechanism of hydrogen in an industrial cold worked Pd–23% Ag alloy is investigated according to its grain size. The microstructural parameters are determined by X-ray diffraction analysis and the diffusion parameters are determined using the galvanostatic electrochemical permeation technique. Two diffusion mechanisms are displayed. For apparent grain size below 40 nm the hydrogen atoms diffuse in the grain boundaries. For grain size above 100 nm, an intergranular diffusion mechanism occurs. For intermediate grain size both mechanisms coexist. Furthermore, the diffusion in the grain boundaries is not faster than the diffusion in the bulk, as generally observed for pure…
Formation of surface roughness on nanocrystalline aluminum samples under straining by molecular dynamics studies
2006
International audience; The surface roughening of nanocrystalline aluminum samples was investigated by molecular dynamics simulations. Attention was focused on the fact that roughness increases with the grain size and the strain. The elastic-plastic transition was found at around 3.5% strain and a reverse Hall-Petch effect was observed under straining conditions. Then, different strain distributions in grains and grain boundaries at the samples surface was highlighted, yielding to the formation of local roughness. Finally, a linear relationship between the magnitude of roughness and the out-of-plane strain component was found.
Is the Physician’s Behavior in Dyslipidemia Diagnosis in Accordance with Guidelines? Cross-Sectional Escarval Study
2013
Background: Clinical inertia has been defined as mistakes by the physician in starting or intensifying treatment when indicated. Inertia, therefore, can affect other stages in the healthcare process, like diagnosis. The diagnosis of dyslipidemia requires $ 2 high lipid values, but inappropriate behavior in the diagnosis of dyslipidemia has only previously been analyzed using just total cholesterol (TC). Objectives: To determine clinical inertia in the dyslipidemia diagnosis using both TC and high-density lipoprotein cholesterol (HDL-c) and its associated factors. Design: Cross-sectional. Setting: All health center visits in the second half of 2010 in the Valencian Community (Spain). Patient…
Prevalence and 30-Day Mortality in Hospitalized Patients With Covid-19 and Prior Lung Diseases.
2021
Patients with pre-existing respiratory diseases in the setting of COVID-19 may have a greater risk of severe complications and even death.A retrospective, multicenter, cohort study with 5847 COVID-19 patients admitted to hospitals. Patients were separated in two groups, with/without previous lung disease. Evaluation of factors associated with survival and secondary composite end-point such as ICU admission and respiratory support, were explored.1,271 patients (22%) had a previous lung disease, mostly COPD. All-cause mortality occurred in 376 patients with lung disease (29.5%) and in 819 patients without (17.9%) (Previous lung disease is a risk factor for mortality in patients with COVID-19.…
Effect of corner over-reinforcing strips on the compressive behaviour of TRM confined masonry columns
2020
Several recent works studied the efficiency of inorganic matrix composites, namely Textile Reinforced Mortar (TRM) or Fabric Reinforced Cementitious Matrix, for enhancing the strength and shortening capacity of masonry columns subjected to axial load. Literature studies were addressed to study the great number of variables involved in the problem, such as the nature and the grade of mortar, the strength of the fabric, the number of reinforcing layers, the type, the arrangement and the strength of the masonry, and helped to draw the first technical guidelines for practitioners and designers. All the experimental works highlighted that the actual performance of TRM confinement in masonry memb…