4 research outputs found
Factors underlying denial of and disbelief in COVID-19 [Fatores subjacentes à negação e descrença em relação à COVID-19]
Objective: To investigate factors that influence or promote disbelief and negative attitudes toward COVID-19. Methods: This was cross-sectional study involving 544 males and females ≥ 18 years of age in Greece between December of 2020 and January of 2021. All participants were informed about the purpose of the study, protection of anonymity, and volunteer participation. Participants completed an online anonymous 40-item questionnaire. Analysis of data included the identification of correlations and use of t-tests and ANOVA. Results: The level of knowledge regarding COVID-19 transmission routes, manifestations, and prevention was high in our sample. Women appeared to have a more positive attitude toward COVID-19 prevention and management than did men (p = 0.032 and p = 0.018, respectively). Younger people (18-30 years of age) seemed to deny the validity of scientific data and mass media reports about ways to deal with the pandemic more commonly than did those > 30 years of age (p = 0.003 and p = 0.001, respectively). People who resided in cities more commonly believed in scientific announcements than did those living in villages (p = 0.029). Conclusions: In order to minimize cases of denial of and disbelief in COVID-19 and to promote vaccination, a series of actions are required. Governments should implement a series of measures to contain the disease, taking into consideration the psychological and social aspects of those policies. © 2022 Sociedade Brasileira de Pneumologia e Tisiologia
Simulation of PZT monitoring of reinforced concrete beams retrofitted with FRP
Summarization: A numerical study has been carried out to simulate an innovative monitoring procedure to detect and localize damage in reinforced concrete beams retrofitted with carbon fiber reinforced polymer (CFRP) unidirectional laminates. The main novelty of the present simulation is its ability to conduct the electro-mechanical admittance monitoring technique by considerably compressing the amount of data required for damage detection and localization. A FEM simulation of electromechanical admittance-based sensing technique was employed by applying lead zirconate titanate (PZT) transducers to acquire impedance spectrum signatures. Response surface methodology (RSM) is finally adopted as a tool for solving inverse problems to estimate the location and size of damaged areas from the relationship between damage and electro-mechanical admittance changes computed at PZT transducer surfaces. This statistical metamodel technique allows polynomial models to be produced without requiring complicated modeling or numerous data sets after the generation of damage, leading to considerably lower cost of creating diagnostic database. Finally, a numerical example is carried out regarding a steel-reinforced concrete (RC) beam model monotonically loaded up to its failure which is also retrofitted by a CFRP laminate to verify the validity of the present metamodeling monitoring technique. The load-carrying capacity of concrete is predicted in the present paper by utilizing an Ottosen-type failure surface in order to better take into account the passive confinement behavior of retrofitted concrete material under the application of FRP laminate.Παρουσιάστηκε στο: Smart Structures and System
Performance of different types of FRCM composites applied to a concrete substrate
This research aimed to investigate the performance of fiber reinforced cementitious matrix (FRCM) composites employed as externally applied strengthening system for reinforced concrete members. The results of an experimental campaign conducted on FRCM composites applied to a concrete substrate are shown and discussed. The composites were comprised of different types of fibers, namely carbon, glass, steel, and basalt fibers, and different types of cementitious matrix. Single-lap direct-shear tests were performed to study the behavior of the different composites. Specimens with different bonded lengths were tested to investigate the stress-transfer mechanism and to investigate the existence of an effective bond length. Comparisons between the peak loads obtained with the direct-shear tests and the tensile strength of the fibers, which provide an indication of the exploitation of the fibers, were carried out