35 research outputs found

    De novo 7p partial trisomy characterized by subtelomeric FISH and whole-genome array in a girl with mental retardation

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    Chromosome rearrangements involving telomeres have been established as one of the major causes of idiopathic mental retardation/developmental delay. This case of 7p partial trisomy syndrome in a 3-year-old female child presenting with developmental delay emphasizes the clinical relevance of cytogenetic diagnosis in the better management of genetic disorders. Application of subtelomeric FISH technique revealed the presence of interstitial telomeres and led to the ascertainment of partial trisomy for the distal 7p segment localized on the telomeric end of the short arm of chromosome 19. Whole-genome cytogenetic microarray-based analysis showed a mosaic 3.5 Mb gain at Xq21.1 besides the approximately 24.5 Mb gain corresponding to 7p15.3- > pter. The possible mechanisms of origin of the chromosomal rearrangement and the clinical relevance of trisomy for the genes lying in the critical regions are discussed

    Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault tolerant control

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    Power maximization has always been a practical consideration in wind turbines. The question of how to address optimal power capture, especially when the system dynamics are nonlinear and the actuators are subject to unknown faults, is significant. This paper studies the control methodology for variable-speed variable-pitch wind turbines including the effects of uncertain nonlinear dynamics, system fault uncertainties, and unknown external disturbances. The nonlinear model of the wind turbine is presented, and the problem of maximizing extracted energy is formulated by designing the optimal desired states. With the known system, a model-based nonlinear controller is designed; then, to handle uncertainties, the unknown nonlinearities of the wind turbine are estimated by utilizing radial basis function neural networks. The adaptive neural fault tolerant control is designed passively to be robust on model uncertainties, disturbances including wind speed and model noises, and completely unknown actuator faults including generator torque and pitch actuator torque. The Lyapunov direct method is employed to prove that the closed-loop system is uniformly bounded. Simulation studies are performed to verify the effectiveness of the proposed method

    Toward farm-level health management of wind turbine systems: Status and scope for improvements

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    An outline of health management for OWFs has been detailed in this chapter with description of various important elements. The need for such farm level management is explained and benefits are discussed. Key gaps to be filled in order to realize such a system are identified. The proposed health management system is mainly based on the existing knowledge of fleet-level management in the aerospace sector. Health management is much broader than CM; there are a number of aspects beyond the prognostics capabilities that are to be designed in order to arrive at a comprehensive maintenance management scheme. A comprehensive maintenance program that is sensitive to the health of the assets and adapts maintenance schedule accordingly, depending upon resource availability, logistics and inventory, is key to cost optimization while ensuring reliability and availability. The advances in CM and diagnostics in wind energy are in the right direction, and many of them are building blocks for health management. Offshore wind faces a number of unique challenges that can be satisfactorily addressed by following a suitable systematic approach. RCM implementation appears to be the most suitable as it encompasses other maintenance strategies and is suitable for farm-level deployment

    Fault diagnostics for electrically operated pitch systems in offshore wind turbines

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    In this chapter, the main objective is to determine the feasibility and applicability of current signature analysis for pitch motors in typical operating profiles. In order to determine pitch system operation profiles, the 5 MW reference wind turbine is simulated in FAST analysis tools developed by National Renewable Energy Laboratory [10]. The pitch systems however pose significant challenge in terms of intermittent, start-stop operating profiles and low speed operations. The main contribution of this chapter is therefore twofold: (1) to develop a detailed physical modelling of various motor faults and study their effect on motor currents in pitch system operating profiles and (2) to determine the feasibility of current signature analysis in such operating profiles. The rest of this chapter is organised as follows: In Section 8.2, determination of the typical pitch profiles from FAST analysis tool is described. Further, a detailed modelling of induction motor with implementation of various fault conditions is described in Section 8.3. In Section 8.4, the motor current signature analysis (MCSA) is tested for pitch motor diagnostics in various wind turbine operating profiles. Finally, accuracy of the fault detection algorithms and steps towards implementation in wind farms are discussed

    Semantic similarity model for risk assessment in forming cloud computing SLAs

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    Cloud computing has enabled users to access various resources and applications as a service and in return pay the provider only for the time for which they are used. Service Level Agreements (SLA) are formed between the user and provider to ensure that the required services and applications are delivered as expected. With the increase of public cloud providers, challenges such as availability, reliability, security, privacy and transactional risk demand detailed assessment during the formation of SLAs. This paper focuses on one sub-category of transactional risk while forming SLAs: namely, performance risk. We argue that performance risk assessment should be done by the user before entering into an SLA with a service provider. We propose to measure performance risk according to the specific context and assessment criteria with the aid of a semantic similarity model for the SLA requirement being negotiated in a cloud computing environment. We show through simulations that the performance risk analysis is more accurate using semantic similarity matching compared with analysis without semantic similarity matching

    Role of metal 3D printing to increase quality and resource-efficiency in the construction sector

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    Demand for the construction of new structures is increasing all over the world. Since the construction sector dominates the global carbon footprint, new construction methods are needed with reduced embodied carbon and high resource efficiency to realize a sustainable future. In this direction, Metal Additive Manufacturing, also known as metal 3D printing, can be an opportunity. Many studies are underway to answer open questions about the metal 3D printing processes and products for high-tech industries. The construction sector must join the metal 3D printing research more actively to enrich the knowledge and experience on this technology, and correctly adapt the process parameters suitable to the construction sector requirements. This paper states the opinion of a research group composed of academics and practitioners from Europe, the US, Japan, and South Africa on how metal 3D printing can be a complementary tool/technology to conventional manufacturing to increase productivity rates, and reduce the costs and CO2 emissions in the construction industry
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