Application of the damage index method for plate-like structures to timber bridges

The paper presents a research recently completed by the authors utilizing a method of damage evaluation for identifying damage in timber bridges, numerically and experimentally. The method utilizes changes in modal strain energy between the undamaged and damaged states of plate-like structures. A finite element model of a laboratory timber bridge was developed to investigate the capabilities and limitations of the method to detect damage. A simple four-girder bridge was fabricated and tested in a laboratory to verify the method. The numerical studies showed that the method can correctly identify single and multiple damage locations within the bridge. The experimental studies also showed promising results for detecting severe damage, but less effective for light and medium damage. Copyright © 2009 John Wiley & Sons, Ltd

Vibration-based damage detection for timber structures in Australia

© 2014 by Nova Science Publishers, Inc. All rights reserved. The use of non-destructive assessment techniques for evaluating structural conditions of aging infrastructure, such as timber bridges, utility poles and buildings, for the past 20 years has faced increasing challenges as a result of poor maintenance and inadequate funding. Replacement of structures, such as an old bridge, is neither viable nor sustainable in many circumstances. Hence, there is an urgent need to develop and utilize state-of-the-art techniques to assess and evaluate the ?health state? of existing infrastructure and to be able to understand and quantify the effects of degradation with regard to public safety. This paper presents an overview of research work carried out by the authors in developing and implementing several vibration methods for evaluation of damage in timber bridges and utility poles. The technique of detecting damage involved the use of vibration methods, namely damage index method, which also incorporated artificial neural networks for timber bridges and time-based non-destructive evaluation (NDE) methods for timber utility poles. The projects involved successful numerical modeling and good experimental validation for the proposed vibration methods to detect damage for simple beams subjected to single and multiple damage scenarios and was then extended to a scaled timber bridge constructed under laboratory conditions. The time-based NDE methods also showed promising trends for detecting the embedded depth and condition of timber utility poles in early stages of that research

Application of the modified damage index method to timber beams

In this paper the use of two existing algorithms developed for global nondestructive evaluation to locate and evaluate localised damage in timber beams is investigated using a finite element model. These damage localisation algorithms were found, through this investigation, not to be effective in locating multiple damage scenarios and unable to evaluate the severity of damage. Hence, modifications on damage index algorithms as well as a hybrid algorithm are proposed to overcome the problems. In this study, experimental modal analysis (EMA) was used as a tool to extract mode shapes for calculating the damage index in the proposed method which utilises changes in modal strain energy between the undamaged and the damaged timber beam model. The modified damage index (MDI) method normalises the mode shape curvature and the hybrid algorithm combines the modified damage index and changes in flexibility algorithms which reflect the changes of natural frequency and mode shape. Analytical evaluations were performed to compare and verify the ability of original and modified damage localisation algorithms in locating single and multiple damage in timber beams. The modified damage index (MDI) algorithm and the hybrid damage algorithm are also used in the experimental studies to validate the effectiveness of the methods to locate and evaluate damage within timber beams by laboratory experiments. © 2007 Elsevier Ltd. All rights reserved

High volumetric energy density capacitors based on new electrode material lanthanum nitride

This is the author accepted manuscript. The final version is available from the American Chemical Society via the DOI in this recordLaN is synthesized via calcining La2O3 in NH3 and studied as capacitive material for energy storage. A volumetric capacitance of 951.3 F cm-3 was found in 1 mol dm-3 Na2SO4 using a current density of 1 Ag-1, with less than 1% loss of capacitance being experienced after 5000 cycles. In addition, 87.3% of the initial capacitance remained at a current density of 10 A g-1. LaN exhibits high capacitance that is attributed to subsurface space charge accumulation with a possible electric double-layer capacitor component. A reversible electrode process ensures long cycle life and favorable electrical charge transfer. The assembled LaN symmetrical capacitor showed high volumetric energy densities, facilitating high-duty applications.National Natural Science Foundation of ChinaFoundation for Innovation Groups of Basic Research in Gansu Provinc

Protocol for Acupuncture Treatment of Lateral Elbow Pain: A Multisite Randomised Controlled Trial in China, Hong Kong, Australia, and Italy

© 2016 Christopher Zaslawski et al. Background. Lateral elbow pain is one of the most common musculoskeletal pains associated with the upper limb and has an estimated population incidence of 1-3%. Methods/Design. This study protocol is for a multisite randomised controlled study and is designed to evaluate the clinical efficacy of acupuncture in the treatment of chronic (over three months' duration) lateral elbow pain. Four study sites, in the People's Republic of China, Hong Kong, Italy, and Australia, will recruit 24 participants each. A total of 96 participants will be randomised to either an acupuncture group or a sham laser control group. The primary outcome measure will be the Disabilities of Arm, Shoulder, and Hand questionnaire with secondary outcome measures of Pain-Free Grip Strength Test, Muscle Tension Test, and a pain visual analogue scale. Discussion. Key features for conducting a multisite international acupuncture randomised clinical trial have been detailed in this protocol. Trial Registration. This trial is registered at Australian and New Zealand Clinical Trial Registry ACTRN12613001138774 on 11 October, 2013

Optimal interdependence between networks for the evolution of cooperation

Recent research has identified interactions between networks as crucial for the outcome of evolutionary games taking place on them. While the consensus is that interdependence does promote cooperation by means of organizational complexity and enhanced reciprocity that is out of reach on isolated networks, we here address the question just how much interdependence there should be. Intuitively, one might assume the more the better. However, we show that in fact only an intermediate density of sufficiently strong interactions between networks warrants an optimal resolution of social dilemmas. This is due to an intricate interplay between the heterogeneity that causes an asymmetric strategy flow because of the additional links between the networks, and the independent formation of cooperative patterns on each individual network. Presented results are robust to variations of the strategy updating rule, the topology of interdependent networks, and the governing social dilemma, thus suggesting a high degree of universality

Investigation of the Phenomenon of Propagated Sensation along the Channels in the Upper Limb Following Administration of Acupuncture and Mock Laser

© 2017 Background Similar to De Qi psychophysical responses, propagated sensation along the channels (PSC) is considered an important phenomenon in traditional Chinese acupuncture. In acupuncture clinical trials, different acupuncture manipulation techniques are used to enhance the propagation of sensation along the channels to facilitate an optimum therapeutic result. Aim To examine and compare the PSC reported by participants in a clinical trial following the administration of acupuncture and inactive mock laser. Methods The study was embedded in a two-arm parallel design multicenter, randomized clinical trial, the Tennis Elbow Acupuncture—International Study—China, Hong Kong, Australia, Italy (TEA IS CHAI). Needle sensations were measured using a validated instrument, the Massachusetts General Hospital Acupuncture Sensation Spreading Scale. Ninety-six participants with lateral elbow pain were randomly allocated into two groups in a 1:1 ratio; the acupuncture treatment group (n = 47) and the mock laser control group (n = 49). Participants in both groups received the intervention at two acupoints, LI10 and LI11, consisting of 2 minutes of either standardized needle manipulation or mock laser at each acupoint with a rest period between each intervention period. Data were collected immediately following the interventions at the first and the ninth session within the clinical trial. Results Although participants in both groups perceived PSC radiating to similar sites along the upper limb, the frequency of the reported radiation sites among the two intervention groups for both radiation up the limb (p < 0.05) and radiation down the limb (p < 0.001) were statistically significantly different. Among the radiating sensation sites recorded within the two study groups, the sensations were reported as radiating a greater distance down the forearm to the wrist compared to up the arm. Evaluation of PSC across the four study sites revealed a statistically significant difference in frequency of the reported radiation down the limb sites in each study group and radiation up the limb sites only in control group only (p < 0.001). Conclusion The findings of the study demonstrated that the PSC phenomenon is not just associated with needling but can be perceived when using a mock laser. Trial registration Australian and New Zealand Clinical Trial Registry reference: ACTRN12613001138774 on 11th of October 2013