Behavioural Study of Concrete Surface Crack Filling Conditions on Surface Rayleigh Wave

In the recent studies of concrete surface crack non-destructive test (NDT), the environmental factors are seldom to be taken into assessment consideration using Rayleigh wave (R-wave) propagation method. Dust, fine sand or water that accumulated in the concrete surface cracks might potentially affect the behaviour of R-wave when it propagated through the cracks. In this study, the effects of filling conditions in concrete surface crack to the properties of R-wave were examined. The targeted parameters that used for studying the behaviour of R-wave are the arrival time of R-wave and its corresponding amplitude. Numerical simulations were conducted for determining the changes of R-wave amplitudes and arrival time when it propagated through a concrete model with a surface crack which containing various filling conditions. Sand and charcoal powder were the materials used for filling the concrete cracks. The results of numerical simulations were then justified by experimental measurements. The comparison between the results of numerical simulation and experimental measurement generated a conclusion where R-wave arrival time and its corresponding amplitude is independent from the predefined filling conditions of concrete surface crack

Behavioural Study of Concrete Surface Crack Filling Conditions on Surface Rayleigh Wave

In the recent studies of concrete surface crack non-destructive test (NDT), the environmental factors are seldom to be taken into assessment consideration using Rayleigh wave (R-wave) propagation method. Dust, fine sand or water that accumulated in the concrete surface cracks might potentially affect the behaviour of R-wave when it propagated through the cracks. In this study, the effects of filling conditions in concrete surface crack to the properties of R-wave were examined. The targeted parameters that used for studying the behaviour of R-wave are the arrival time of R-wave and its corresponding amplitude. Numerical simulations were conducted for determining the changes of R-wave amplitudes and arrival time when it propagated through a concrete model with a surface crack which containing various filling conditions. Sand and charcoal powder were the materials used for filling the concrete cracks. The results of numerical simulations were then justified by experimental measurements. The comparison between the results of numerical simulation and experimental measurement generated a conclusion where R-wave arrival time and its corresponding amplitude is independent from the predefined filling conditions of concrete surface crack

Trajectories of Early-Onset Rhinitis in the Singapore GUSTO Mother-offspring Cohort

10.1111/cea.13803Clinical and Experimental Allerg

Trajectories of early‐onset rhinitis in the Singapore GUSTO mother‐offspring cohort

Background: The natural history of childhood rhinitis is not well described.Objective: This study aimed to identify different rhinitis trajectories in early childhood and their predictors and allergic associations.Methods: Rhinitis symptoms were ascertained prospectively from birth until 6 years using standardized questionnaires in 772 participants. Rhinitis was defined as one or more episodes of sneezing, runny and/or blocked nose >2 weeks duration. Latent trajectories were identified using group‐based modelling, and their predictive risk factors and allergic associations were examined.Results: Three rhinitis trajectory groups were identified: 7.6% (n = 59) were termed early transient rhinitis, 8.6% (n = 66) late transient rhinitis, and 6.6% (n = 51) persistent rhinitis. The remaining 77.2% (n = 596) were classified as non‐rhinitis/reference group. Early transient rhinitis subjects were more likely of Indian ethnicity, had siblings, reported childcare attendance, early wheezing and eczema in the first 3 years of life. Late transient rhinitis was associated with antenatal exposure to smoking, higher maternal education levels, and wheezing at age 36‐72 months. Persistent rhinitis was associated with male gender, paternal and maternal history of atopy, eczema, and house dust mite sensitization.Conclusions & Clinical Relevance: Risk factors for early transient rhinitis involve a combination of genetic and early environmental exposures, whereas late transient rhinitis may relate to maternal factors and early respiratory infections independent of atopy. In contrast, persistent rhinitis is strongly associated with atopic risk and likely represents the typical trajectory associated with allergic disorders. Allergic rhinitis symptoms may commence as early as the first year of life and may inform development of early interventive strategies

Platelet inhibition to target reperfusion injury trial: Rationale and study design

10.1002/clc.23110CLINICAL CARDIOLOGY4215-1