25 research outputs found

    New System for the Acceleration of the Airflow in Wind Turbines

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    Background: This patent is based on the wind industry technology called Diffuser Augmented Wind Turbines (DAWTs). This technology consists of a horizontal axis wind turbine, which is housed inside a duct with diverging section in the direction of the free air stream. In this paper, a review of preceding patents related to this technology is carried out. Objective: This paper presents an innovative patent to improve the performance of horizontal axis wind turbines. In particular, this system is aimed at improving the performance of those turbines that otherwise might not be installed due to the low wind resource existing at certain locations. Methods: The most innovative elements of this patent are: (1) the semi-spherical grooves, which are mechanized on the surface of the two diffusers in order to guarantee a more energetic boundary layer; (2) the coaxial diffuser, which is located downwind following the first diffuser in order to increase the suction effect on the air mass close to the inlet; (3) the coaxial rings located around the first diffuser outlet, which are used to deflect the external airflow toward the turbine wake; and (4), the selforientating system to orientate the system by the prevailing wind direction. Results: An application of the patent for increasing the power generated by a horizontal axis wind turbine with three blades is presented. The patent is designed and its performance is evaluated by using a Computational Fluid Dynamics code. The numerical results show that this system rises the airflow going through the rotor of the turbine. Conclusion: The patented device is an original contribution aimed at enabling a more profitable installation of wind turbines in places where the wind resource is insufficient because of the wind shear caused both by the proximity of the earth and the obstacles on the earth surface.This work was supported by the OASIS Research Project that was cofinanced by CDTI (Spanish Science and Innovation Ministry) and developed with the Spanish companies: Iridium, OHL Concesiones, Abertis, Sice, Indra, Dragados, OHL, Geocisa, GMV, Asfaltos Augusta, Hidrofersa, Eipsa, PyG, CPS, AEC and Torre de Comares Arquitectos S.L and 16 research centres. The authors also acknowledge the partial funding with FEDER funds under the Research Project FC-15-GRUPIN14-004. Finally, we also thank Swanson Analysis Inc. for the use of ANSYS University Research programs as well as the Workbench simulation environment

    Modelos para gestão de riscos em cadeias de suprimentos: revisão, análise e diretrizes para futuras pesquisas

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    2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease

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    The recommendations listed in this document are, whenever possible, evidence based. An extensive evidence review was conducted as the document was compiled through December 2008. Repeated literature searches were performed by the guideline development staff and writing committee members as new issues were considered. New clinical trials published in peer-reviewed journals and articles through December 2011 were also reviewed and incorporated when relevant. Furthermore, because of the extended development time period for this guideline, peer review comments indicated that the sections focused on imaging technologies required additional updating, which occurred during 2011. Therefore, the evidence review for the imaging sections includes published literature through December 2011

    An application of the AHP in vendor selection of a telecommunications system

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    Vendor selection of a telecommunications system is an important problem to a telecommunications company as the telecommunications system is a long-term investment for the company and the success of telecommunications services is directly affected by the vendor selection decision. Furthermore, the vendor selection of a telecommunications system is a complex multi-person, multi-criteria decision problem. The group decision-making process can be improved by a systematic and logical approach to assess priorities based on the inputs of several people from different functional areas within the company. The analytic hierarchy process (AHP) can be very useful in involving several decision-makers with different conflicting objectives to arrive at a consensus decision. In this paper, an AHP-based model is formulated and applied to a real case study to examine its feasibility in selecting a vendor for a telecommunications system. The use of the proposed model indicates that it can be applied to improve the group decision making in selecting a vendor that satisfies customer specifications. Also, it is found that the decision process is systematic and that using the proposed AHP model can reduce the time taken to select a vendor.Telecommunications Systems Vendors Selection AHP

    A risk-based maintenance management model for toll road/tunnel operations

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    Preventive maintenance (PM) has long been recognized as a method to increase equipment reliability and availability. However, for equipment in complex plant installations like toll road/tunnel systems, to carry out PM on all components may not be feasible, or, may end up with excessive maintenance costs. This paper describes how a risk-based maintenance management model was formulated to systematically prioritize PM activities. The model was based on the five core elements of the risk management process (RMP): identification, measurement, assessment, valuation, and control and monitoring. This model was applied to a toll road/tunnel company in Hong Kong to enhance the PM operations of its lighting system. The improvements recommended in this case study show that the application of RMP in preventive maintenance could effectively identify and assess potential risks for equipment and facilities. The RMP results provide quantified information for decision-makers to select the best course of actions for implementing a more cost-effective risk-based PM system.Risk management process, preventive maintenance, toll road/tunnel, operations,

    A world-wide survey of current practices in the management of risk within electrical supply projects

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    A survey is described which examines the current risk handling practices in evaluating capital development projects (transmission, generation and distribution) within the electricity supply industry world-wide. As risk perception is an important aspect of risk management, the attitudes towards and the barriers created by management to risk management plus the benefits perceived are examined and compared with the results of previous surveys. The survey will assist also in determining the need and feasibility of applying a risk management process to capital budgets in investments such as transmission construction works and other appropriate applications. The survey has demonstrated that a formal risk management process is more likely to apply to large, complex projects with potential of cost overrun. However, the criteria for application are likely to depend more on overcoming managers concerns about time involvement, human/organizational resistance and understanding of quantitative techniques, such as assessing probability distributions, determining and interpreting expected values, variances, and risk management output results, so as to appreciate the benefits and enable effective decisions to be made. The world-wide survey confirms that there is a drive towards a more thorough assessment of risks than previously recorded, with a formal risk management process that will meet the expectations of business growth and project sponsors and ensure that all risks are actively managed throughout the life cycle of a project.Risk Management, Practices, Power Generation, Power Distribution, World-wide Survey, Electricity Supply Industry,

    System-on-a-Package (SOP) Substrate and Module with Digital, RF and Optical Integration

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    The Packaging Research Center has been developing next generation system-on-a-package (SOP) technology with digital, RF, and optical system integration on a single package. SOP aims to utilize the best of on-chip SOC integration and package integration to achieve highest system performance at the lowest cost. The microminiaturized multifunctional SOP package is highly integrated and fabricated on large area substrates similar to the wafer-to-IC concept. In addition to novel mixed signal design methodologies, SOP research at PRC is targeted at developing enabling technologies for package level integration including ultra-high density wiring, embedded passive components, embedded optical interconnects, wafer level packaging and fine pitch assembly. Several of these enabling technologies have been recently integrated into the first successful system level demonstration of SOP technology using the Intelligent Network Communicator (INC) testbed. This paper reports on the latest INC and SOP testbed results at the PRC and provides an insight into the future SOP integration strategy for convergent microsystems. The focus of this paper is on integration of materials, processes and structures in a single package substrate for System-on-a-Package (SOP) implementation. I
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