Search results for "estres"
showing 10 items of 111 documents
Simplified Procedure for Evaluating the Effects of Creep and Shrinkage on Prestressed Concrete Girder Bridges and the Application of European and Nor…
2013
The effects of time-dependent phenomena on concrete prestressed girder bridges are investigated. The study concerns the case of bridges built directly in their final configuration and that of bridges built by a sequence of stages in which geometry, restraints, and loads vary until the final configuration is achieved. An analytical approach based on the principles of aging linear viscoelasticity and the age-adjusted effective modulus method is followed. The paper has two aims: the first is to provide an efficient and simplified tool for the evaluation of the structural response in the early stages of design; the second is to compare the results of the analyses on actual cases of bridges when…
Programa experimental per al foment de l'ús de llibres de text en dispositius electrònics : estudi d'un cas
2015
L'aparició al mercat de les tauletes digitals ha marcat un abans i un després en l'ensenyament. Aquesta eina tecnològica es perfila com un recurs innovador de cara a la seua utilització educativa. I, com tots sabem, l'escola no pot quedar-se al marge d'aquesta revolució tecnològica. Analitzar l'impacte sobre l'alumnat de l'ús de les tauletes digitals, extraure els seus avantatges i inconvenients i generar idees sobre el seu ús ens pot portar a una educació de qualitat. En aquest article s’analitza la posada en pràctica d’aquest nou projecte anomenat Programa experimental per al foment de l'ús de llibres de text en dispositius electrònics anomenats tauletes digitals en un centre de titularit…
Tutorial multimèdia per al desenvolupament de treballs de fi de grau en Informació i Documentació
2013
La pàgina web i els materials creats formen part del projecte d'Innovació Educativa: Tutorial multimèdia per al desenvolupament de treballs de fi de grau en Informació i Documentació. La preparació i defensa d’un Treball de Fi de Grau constitueix una de les principals novetats derivades del procés de construcció de l’Espai Europeu d’Educació Superior (EEES). En aquest treball queden reflectides totes les habilitats adquirides pels estudiants en els anys previs a la finalització del Grau, atès que els estudiants han d’enfrontar-se en el mateix al procés de generació autònoma de coneixement i a les dificultats que comporta un treball de tipus pràctic. El present document recull l’experiència …
Stressing sequence of steel cable-stayed bridges built by cantilevering
2015
The construction of cable-stayed bridges by cantilevering implies several changes of geometry, stress and strain patterns during the assemblage of segments. The main target to be satisfied in the construction process is the achievement of the required final geometry and of a convenient state of stress for self-weight and sustained loads. The sequence of stay stressing and the values of prestressing forces at each stage of segment assembling have the main role for reaching the desired result of design, due to the large redundancy of cable-stayed structures.Among the different procedures proposed in the literature for initial cable force determination, the Partial Elastic Scheme (PES) Method …
THE REHABILITATION THROUGH EXTERNAL PRESTRESSING OF HISTORICAL REINFORCED CONCRETE BRIDGES WITH REDUCED PERFORMANCE: A CASE STUDY
2022
Many existing reinforced concrete bridges exhibit behaviour at the Service Limit State and the Ultimate Limit State which can be considered unsatisfactory with respect to the current provisions of Codes, but which are actually deficiencies deriving from obsolete calculation methods, structure age, material degradation, diffuse or localized corrosion and increased loads. Among these, cantilever bridges with half-joints may present a decrease in global safety coefficients for the most stressed current sections of the deck or in the local ones, that affect the performance of elements sensitive to degradation, such as Gerber saddles. In these cases, simple strengthening interventions through ex…
Ex post-facto study of long-term stress in a sample of adoptees
2015
In this work we study the impact of relinquishment and the adoption process in posttraumatic symptoms and stressful life events in a group of 55 adults that were adopted as children after the Spanish Civil War (1936-1939). The effects of institutionalization, maltreatment and traumatic revelation of the adopted status have also been studied. No significant differences were found between institutionalized and non-institutionalized adoptees in posttraumatic symptomatology and stressful life events frequency. However, maltreated adoptees scored significantly higher in intrusion, arousal and stressful life events frequency than non-maltreated. Similar differences were found in the comparison be…
Quantitative parameters and ecological implications of a specialized tritrophic interaction involving a seed-feeding tortricid, Pseudargyrotoza conwa…
2014
Producción Científica
Factorial validity of the Maslach Burnout Inventory (MBI-HSS) among Spanish professionals
2005
OBJECTIVE: To assess the factorial validity and internal consistency of the Maslach Burnout Inventory (MBI-HSS). METHODS: In a sample consisting of 705 Spanish professionals from diverse occupational sectors (health, education, police and so one), seven plausible factorial models hypothesized were compared using LISREL 8. RESULTS: The four-factor oblique solution and the three-factor oblique solution showed the best and similar fit. Deletion of Item 12 and Item 16, taking into consideration the suggestions in the manual, improved the goodness of fit for both models. The four-factor oblique model suggests that, in addition to Emotional Exhaustion (EE) and Depersonalization (DP), Personal Acc…
Quality control of B-lines analysis in stress Echo 2020
2018
Background The effectiveness trial “Stress echo (SE) 2020” evaluates novel applications of SE in and beyond coronary artery disease. The core protocol also includes 4-site simplified scan of B-lines by lung ultrasound, useful to assess pulmonary congestion. Purpose To provide web-based upstream quality control and harmonization of B-lines reading criteria. Methods 60 readers (all previously accredited for regional wall motion, 53 B-lines naive) from 52 centers of 16 countries of SE 2020 network read a set of 20 lung ultrasound video-clips selected by the Pisa lab serving as reference standard, after taking an obligatory web-based learning 2-h module ( http://se2020.altervista.org ). Each te…
Influence of axial force and corrosion on failure of prestressed concrete structures considering M-V interaction
2021
Abstract Existing prestressed concrete structures suffer from degradation of prestressing for two main reasons: a defect of the sheath infills (cement grout) of bonded tendons, and corrosion of steel strands. These two causes, often concomitant, lead to a reduction over time of the effectiveness of initial prestressing, in addition to the ordinary tension losses due to concrete shrinkage and creep, and to steel relaxation. In many cases a consequence of bad grouting in bonded tendons is that the structure shows an intermediate behavior between that of external prestressing and that of internal bonded prestressing. This, added to damage to wires due to corrosion, makes it essential for the d…