969 resultados para field testing


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The safety of an in-service brick arch railway bridge is assessed through field testing and finite-element analysis. Different loading test train configurations have been used in the field testing. The response of the bridge in terms of displacements, strains, and accelerations is measured under the ambient and design train traffic loading conditions. Nonlinear fracture mechanics-based finite-element analyses are performed to assess the margin of safety. A parametric study is done to study the effects of tensile strength on the progress of cracking in the arch. Furthermore, a stability analysis to assess collapse of the arch caused by lateral movement at the springing of one of the abutments that is elastically supported is carried out. The margin of safety with respect to cracking and stability failure is computed. Conclusions are drawn with some remarks on the state of the bridge within the framework of the information available and inferred information. DOI: 10.1061/(ASCE)BE.1943-5592.0000338. (C) 2013 American Society of Civil Engineers.

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Recent research has shown that higher ambient turbulence leads to better wake recovery, so turbines could be installed in closer proximity in real tidal flows than might be assumed from typical towing tank tests that do not take into account turbulent inflow conditions. The standard tools to assess flow velocities in field conditions are Doppler based sonar devices, such as Acoustic Doppler Profilers (ADPs) or Acoustic Doppler Velocimeters (ADVs). The use of these devices poses some challenges when assessing the wake of a tidal turbine. While ADPs allow the three-dimensional measurement of a velocity profile over a distance, the data is calculated as a mean of three diverging beams and with low temporal resolution. ADVs can measure with higher sampling frequency but only at a single point in the flow. During the MaRINET testing of the SCHOTTELSIT turbine at the QUB tidal test site in Portaferry, Northern Ireland, ADP and ADV measurements were successfully tested.Two methods were employed for measuring the wake: firstly, with a rigidly mounted ADP and secondly, with a submerged ADV which was streamed behind the turbine. This paper presents the experimental set-up and results and discusses limitations and challenges of the two methods used.

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Like any new technology, tidal power converters are being assessed for potential environmental impacts. Similar to wind power, where noise emissions have led to some regulations and limitations on consented installation sites, noise emissions of these new tidal devices attract considerable attention, especially due to the possible interaction with the marine fauna. However, the effect of turbine noise cannot be assessed as a stand-alone issue, but must be investigated in the context of the natural background noise in high flow environments. Noise measurements are also believed to be a useful tool for monitoring the operating conditions and health of equipment. While underwater noise measurements are not trivial to perform, this non-intrusive mon- itoring method could prove to be very cost effective. This paper presents sound measurements performed on the SCHOTTEL Instream Turbine as part of the MaRINET testing campaign at the QUB tidal test site in Portaferry during the summer of 2014. This paper demonstrates a comparison of the turbine noise emissions with the normal background noise at the test site and presents possible applications as a monitoring system.

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The Rapid Assessment of Disability (RAD) questionnaire measures the magnitude and impact of disability and aims to inform the design of disability inclusive development programs. This paper reports the psychometric evaluation of the RAD.

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Mode of access: Internet.

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Semi-permeable membrane devices (SPMDs) were loaded with deuterated anthracene and pyrene as performance reference compounds (PRCs) and deployed at a test site in four different chambers (open and closed box chamber, bowl chamber and cage chamber) for 29 days. The losses of PRCs and the uptake of polyaromatic hydrocarbons (PAHs) from the ambient air were quantified. UV-B levels measured in each deployment chamber indicated that SPMDs would be exposed to the most UV-B in the cage chamber and open box chamber. Significantly less PAHs were quantified in SPMDs deployed in the cage chamber and open box chamber compared to samplers from the other two chambers, suggesting that photodegradation of PAHs had occurred. The loss of PRCs confirmed these results but also showed that photodegradation was occurring in the closed box chamber. The bowl chamber appears to provide the best protection from the influence of direct photodegradation. (c) 2006 Elsevier Ltd. All rights reserved.