scholarly journals Health Monitoring of Stress-Laminated Timber Bridges Assisted by a Hygro-Thermal Model for Wood Material

2020 ◽  
Vol 11 (1) ◽  
pp. 98
Author(s):  
Stefania Fortino ◽  
Petr Hradil ◽  
Keijo Koski ◽  
Antti Korkealaakso ◽  
Ludovic Fülöp ◽  
...  

Timber bridges are economical, easy to construct, use renewable material and can have a long service life, especially in Nordic climates. Nevertheless, durability of timber bridges has been a concern of designers and structural engineers because most of their load-carrying members are exposed to the external climate. In combination with certain temperatures, the moisture content (MC) accumulated in wood for long periods may cause conditions suitable for timber biodegradation. In addition, moisture induced cracks and deformations are often found in timber decks. This study shows how the long term monitoring of stress-laminated timber decks can be assisted by a recent multi-phase finite element model predicting the distribution of MC, relative humidity (RH) and temperature (T) in wood. The hygro-thermal monitoring data are collected from an earlier study of the Sørliveien Bridge in Norway and from a research on the new Tapiola Bridge in Finland. In both cases, the monitoring uses integrated humidity-temperature sensors which provide the RH and T in given locations of the deck. The numerical results show a good agreement with the measurements and allow analysing the MCs at the bottom of the decks that could be responsible of cracks and cupping deformations.

2013 ◽  
Vol 838-841 ◽  
pp. 1087-1091
Author(s):  
Xu Hui Hu ◽  
Ning Zhong ◽  
Shi Hong Jing

Study and design a set of economical and practical mid-and-long term monitoring system for long-span prestressed concrete continuous rigid frame bridge relying on the engineering of Xintan Qijiang Bridge in Chongqing. Master the static characteristics of such parameters as displacement, stress and external cable force during operation process of bridge through finite element model and make a comparative analysis of the relevant data after running for two years to test the feasibility and practicability of mid-and-long term monitoring system for continuous rigid frame bridge suggested in the paper.


Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 795
Author(s):  
Valentina Secchi ◽  
Gerolamo Masala ◽  
Andrea Corda ◽  
Francesca Corda ◽  
Enrica Potop ◽  
...  

Early diagnosis of tendon injuries and accurate long-term monitoring of the healing process are key for equine veterinarians that use conventional ultrasonography. The development of strain elastography could improve the management of clinical cases. The aim of the study was to assess the intraobserver repeatability and interobserver reproducibility of manual measurements of the colored areas of the tendons within elastograms and to standardize this manual modality by comparing the analysis of the images with ImageJ. Twenty elastograms of the injured superficial digital flexor tendons (SDFTs) of horses were analyzed by two different operators after an acute injury was diagnosed with ultrasonography. Statistical analysis demonstrated excellent intraobserver repeatability (intraclass correlation coefficient, ICC = 0.949) and good interobserver reproducibility (ICC = 0.855) for manual measurements performed with tools available on the ultrasound unit. A good agreement between manual measurements and measurements performed with ImageJ (ICC=0.849) was then demonstrated. Despite its subjectivity, the manual modality proved to be a valid method for analyzing images obtained with strain elastography.


2014 ◽  
Vol 5 (2) ◽  
pp. 195-202 ◽  
Author(s):  
Bettina Franke ◽  
Steffen Franke ◽  
Andreas Müller

Author(s):  
Sarah Gwyn ◽  
Andrew W. Nute ◽  
Eshetu Sata ◽  
Zerihun Tadesse ◽  
Ambahun Chernet ◽  
...  

Programs to eliminate trachoma as a public health problem use prevalence of the clinical sign trachomatous inflammation—follicular (TF) in 1- to 9-year-olds in endemic districts to make decisions to begin or end mass drug administration with azithromycin. Trachomatous inflammation—follicular is used as a proxy for transmission of ocular Chlamydia trachomatis infection. Long-term monitoring of previously endemic districts for recrudescence of ocular C. trachomatis infection would benefit from a simple blood test that could be integrated with other public health programs. In this study, we evaluated multiple tests to measure antibodies against the C. trachomatis antigen Pgp3—a multiplex bead assay (MBA), an ELISA, and two versions of a lateral flow assay (LFA)—in four districts of the Amhara region of Ethiopia with varying levels of TF. Seroprevalence and seroconversion rate (SCR) results were proportional to TF prevalence by district for most tests, with the notable exception of the LFA using colloidal gold as the developing reagent. Changing the test developing reagent to black latex improved agreement between serological measures and TF prevalence and in inter-rater agreement. Seroconversion rate estimates using data derived from the LFA-gold assay were inconsistent with the shape of the age-seroprevalence curve, which did not increase in older ages. These data revealed potential complications with using SCR that will need further evaluation. Data from MBA, ELISA, and LFA with the black test line showed good agreement with each other and proportionality to TF estimates, providing further data that serology has potential utility for trachoma surveillance.


Author(s):  
Ana Ivanovic´ ◽  
Jianfeng Zhu ◽  
Richard Neilson ◽  
Finbarr O’Neill

The envionmental impact of towed demersal gears on benthic communities has been of concern for the last couple of decades. Knowledge of the response of benthic habitats to impacts from fishing gears is of great importance to the ecosystem and the long-term management of sustainable fisheries. An on-going EU project, DEGREE (DEvelopment of Fishing Gears with Reduced Effects on the Environment), addresses this concern by focusing on quantifying the environmental and ecological impacts of fishing, developing fishing gears with reduced environmental impact, and assessing the socio-economic consequences of these changes. This paper focuses primarily on the modelling of the interaction between a gear component, the roller clump of a twin trawl, and the seabed in terms of penetration and disturbance of the seabed. A finite element model of this interface has been developed and is able to predict the penetration depth, sediment displacement and the pressure field associated with each gear component. In order to verify these predictions, sea trials have taken place over a range of sediment types at depths accessible to scientific divers using SCUBA diving techniques. This has allowed sampling of the seabed and profiling of the disturbed region for comparison with the model results. Good agreement is found.


Author(s):  
Barbara S. Minsker ◽  
Charles Davis ◽  
David Dougherty ◽  
Gus Williams

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