Condition-based maintenance of wind turbine blades

The blades of offshore wind farms (OWTs) are susceptible to a wide variety of diverse sources of damage. Internal impacts are caused primarily by structure deterioration, so even though outer consequences are the consequence of harsh marine ecosystems. We examine condition-based maintenance (CBM) for a multiblade OWT system that is exposed to environmental shocks in this work. In recent years, there has been a significant rise in the number of wind turbines operating offshore that make use of CBMs. The gearbox, generator, and drive train all have their own vibration-based monitoring systems, which form most of their foundation. For the blades, drive train, tower, and foundation, a cost analysis of the various widely viable CBM systems as well as their individual prices has been done. The purpose of this article is to investigate the potential benefits that may result from using these supplementary systems in the maintenance strategy. Along with providing a theoretical foundation, this article reviews the previous research that has been conducted on CBM of OWT blades. Utilizing the data collected from condition monitoring, an artificial neural network is employed to provide predictions on the remaining life. For the purpose of assessing and forecasting the cost and efficacy of CBM, a simple tool that is based on artificial neural networks (ANN) has been developed. A CBM technique that is well-established and is based on data from condition monitoring is used to reduce cost of maintenance. This can be accomplished by reducing malfunctions, cutting down on service interruption, and reducing the number of unnecessary maintenance works. In MATLAB, an ANN is used to research both the failure replacement cost and the preventative maintenance cost. In addition to this, a technique for optimization is carried out to gain the optimal threshold values. There is a significant opportunity to save costs by improving how choices are made on maintenance to make the operations more cost-effective. In this research, a technique to optimizing CBM program for elements whose deterioration may be characterized according to the level of damage that it has sustained is presented. The strategy may be used for maintenance that is based on inspections as well as maintenance that is based on online condition monitoring systems

Contrasting Views of Complexity and Their Implications For Network-Centric Infrastructures

There exists a widely recognized need to better understand and manage complex “systems of systems,” ranging from biology, ecology, and medicine to network-centric technologies. This is motivating the search for universal laws of highly evolved systems and driving demand for new mathematics and methods that are consistent, integrative, and predictive. However, the theoretical frameworks available today are not merely fragmented but sometimes contradictory and incompatible. We argue that complexity arises in highly evolved biological and technological systems primarily to provide mechanisms to create robustness. However, this complexity itself can be a source of new fragility, leading to “robust yet fragile” tradeoffs in system design. We focus on the role of robustness and architecture in networked infrastructures, and we highlight recent advances in the theory of distributed control driven by network technologies. This view of complexity in highly organized technological and biological systems is fundamentally different from the dominant perspective in the mainstream sciences, which downplays function, constraints, and tradeoffs, and tends to minimize the role of organization and design

Constructing resilience through security and surveillance: The politics, practices and tensions of security-driven resilience

This article illuminates how, since 9/11, security policy has gradually become more central to a range of resilience discourses and practices. As this process draws a wider range of security infrastructures, organizations and approaches into the enactment of resilience, security practices are enabled through more palatable and legitimizing discourses of resilience. This article charts the emergence and proliferation of security-driven resilience logics, deployed at different spatial scales, which exist in tension with each other. We exemplify such tensions in practice through a detailed case study from Birmingham, UK: ‘Project Champion’ an attempt to install over 200 high-resolution surveillance cameras, often invisibly, around neighbourhoods with a predominantly Muslim population. Here, practices of security-driven resilience came into conflict with other policy priorities focused upon community-centred social cohesion, posing a series of questions about social control, surveillance and the ability of national agencies to construct community resilience in local areas amidst state attempts to label the same spaces as ‘dangerous’. It is argued that security-driven logics of resilience generate conflicts in how resilience is operationalized, and produce and reproduce new hierarchical arrangements which, in turn, may work to subvert some of the founding aspirations and principles of resilience logic itself

Economic Underperformance: SSA from Planning through Life Crisis Coping and Structural Adjustment To What Strategic Agendas?

For ADB

Disaster Risk Management by Communities and Local Governments

This study refers to disaster risk management at the local level. The topic was selected by the members of the Natural Disasters Network of the Regional Policy Dialogue, and was presented during its 3rd Meeting, on March 6 and 7, 2003. The goal of this document is to achieve a better knowledge of the best practices and benefits that disaster risk management represents for Latin America and the Caribbean. Included are comparative case studies of the Philippines, Colombia, Guatemala and Switzerland. Also discussed are strengths and weaknesses of local organizations in decentralized systems and financial services for disaster risk management.Disasters, Financial Risk, Decentralization, Civil Society, Environment, disaster risk management

Small business innovation research. Abstracts of completed 1987 phase 1 projects

Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

Vibroacoustic transformer condition monitoring

Throughout the life of a transformer the effects of mechanical shocks, insulation aging, thermal processes and short circuit forces will cause deformations in the winding. This deformation can lead to vibration in the transformer and mechanical fatigue of the solid insulation. Defects which form in a transformers structure can cause faults such as partial discharge, hot spots and arcing. These faults generate combustible gases which can be analysed for condition assessment of the transformer. The development of a suitable and cost effective vibration measurement system forms a key part of this research project. A monitoring system is developed for real-time vibration analysis. An embedded capacitive accelerometer is used in conjunction with an Arduino microcontroller to record vibrations. The sensor platform is designed to communicate wirelessly via XBee radios to a terminal computer. A software program and user interface is designed as a tool for analysis. The outcomes and benefits of these works are primarily based on determining the condition of transformer insulation through measurements of vibration. Following a working measurement system, suitable transformer sites are monitored. Spectral analysis is performed in the frequency domain to determine a correlation with gas analysis results. The validity of vibroacoustic measurement as a predictive maintenance tool is subsequently evaluated. Six transformers are chosen for vibration monitoring with analysis of the vibration signatures correlated to the dissolved gas analysis reports at each site. The vibration signatures at each location are analysed using the Short Time Fourier Transform and frequency peaks compared for the different sites. It was noted that sensor location does not have a large impact on vibration magnitudes and identifying the frequency components present in the signal. However, from the signatures obtained there is not enough variation in magnitude or frequency components to suggest that this method can identify the type of fault present

Editorial: Improving urban regeneration and renewal outcomes by engaging an urban psychology

A crisis in mental health, especially in economically deprived neigh bour hoods, can present a significant barrier to successful urban regeneration projects. It follows that urban regeneration not only has a stake in promoting mental health care generally but, through its place making influence on physical and social structures, has a more direct responsibility to address poor mental health and sustain well-being where it exists. In support of a psychologically informed urban regeneration, this Special Issue sets out the case for a systematised intellectual and practice-based discipline and movement: An urban psychology, with an explicit therapeutic mission. It incorporates 10 articles delivered initially at Europe’s first urban psychology summit — City, Psychology, Place — held at the University of Liverpool in London campus in June 2019. In this editorial introduction, we reflect upon the need for an urban psychology at this historical juncture and offer our views on the work which such a body of practical knowledge might do to improve regeneration and renewal outcomes. We conclude that there can be no enduring economic, social or physical regeneration of distressed, failing or failed communities unless there is first ‘regeneration in support of life itself’ (RISLI)