1,720,960 research outputs found
Hawaii Deep Water Cable Program, phase II : conceptual design study : integrated control system for the HDWC cable laying
Get PDFThe Hawaii Deep Water Cable Program has been established to evaluate and resolve the technical problems associated with laying a power cable from the island of Hawaii to the island of Oahu in the State of Hawaii. This cable, 250km (150m) long, is to be laid at a maximum depth of 2135m (7000ft) under design seas of 2.5m (8ft) and surface currents up to 1.5m/s (3kts). One of the many problems associated with this task is the integrated control system for the deployment vessel, the subject of this study. The intent of this study is to provide a conceptual design for an integrated control system that identifies its basic method of operation, equipment required, and to determine potential problem areas. The main objective of the control system is to promptly lay the cable on the bottom, properly tensioned and properly located. In general, this is achieved by accurately measuring a variety of cable and vessel parameters, monitoring the vessel location and controlling the cable payout rate and the vessel position. In conclusion, a control system that can properly position and tension the cable for the Hawaii program is possible. Most of the components for the system are commercially available with the exception of the surface cable angle measurement. The cable lay and control will involve added complexities because of the depth, cable dynamics, path width and bottom slopes; these should be tested in the HDWC demonstration program
Analysis of Seafloor Surveys, Inc. precision bottom data between Maui and Oahu in determination of a potential cable route
Get PDFObjectives of study. To review and analyze Seafloor Surveys, Inc. bathymetry data in determining the feasibility of laying a cable from Maui to Oahu. To identify an acceptable path if possible. When applicable, identify the path width, obstacles on or near the path, and the required cable tension and bend radius requirements along a proposed cable route
Draft report Hawaii Deep Water Cable Program (HDWCP) : cable repair rationale
Get PDFThe Hawaii Deep Water Cable (HDWC) program has a major objective of determining the technical feasibility of deploying and operating, over a service life of thirty years, a submarine power transmission cable between Kohala on the island of Hawaii and the Makapuu area of Oahu. To this end the (HDWC) program has incorporated work elements to: 1) build and laboratory test a prototype cable that is designed to meet a wide range of environmental conditions expected in the route between the islands; 2) conduct at-sea tests to determine the feasibility of accurately laying a commercial cable with the proper tensions; and 3) perform bottom roughness surveys to establish the existence of acceptable cable laying routes and determine the laying requirements. Another task which this report addresses, is assessing the requirements for repairing the submarine portion of an inter-island cable system should damage occur during its operating life. The sections which follow discuss first the report prepared by Pirelli Cable Corporation, titled HDWC Program Repair Rationale which is included as Appendix A, and then develop a baseline approach to a repair scenario and a conceptual arrangement of equipment requirements integrated into the expected cable laying concept developed on other tasks of the HDWC program
Modeling the Physical and Biochemical Influence of Ocean Thermal Energy Conversion Plant Discharges into their Adjacent Waters
Get PDFThis paper describes the modeling work by Makai Ocean Engineering, Inc. to simulate the biochemical effects of of the nutrient-enhanced seawater plumes that are discharged by one or several 100 megawatt OTEC plants. The modeling is needed to properly design OTEC plants that can operate sustainably with acceptably low biological impact. In order to quantify the effect of discharge configuration and phytoplankton response, Makai Ocean Engineering implemented a biological and physical model for the waters surrounding O`ahu, Hawai`i, using the EPA-approved Environmental Fluid Dynamics Code (EFDC). Each EFDC grid cell was approximately 1 square kilometer by 20 meters deep, and used a time step of three hours. The biological model was set up to simulate the biochemical response for three classes of organisms: Picoplankton ( 20 um) e.g., diatoms. The dynamic biological phytoplankton model was calibrated using chemical and biological data collected for the Hawaii Ocean Time Series (HOTS) project. Peer review of the biological modeling was performed. The physical oceanography model uses boundary conditions from a surrounding Hawai'i Regional Ocean Model, (ROM) operated by the University of Hawai`i and the National Atmospheric and Oceanic Administration. The ROM provided tides, basin scale circulation, mesoscale variability, and atmospheric forcing into the edges of the EFDC computational domain. This model is the most accurate and sophisticated Hawai'ian Regional Ocean Model presently available, assimilating real-time oceanographic observations, as well as model calibration based upon temperature, current and salinity data collected during 2010 near the simulated OTEC site. The ROM program manager peer-reviewed Makai's implementation of the ROM output into our EFDC model. The supporting oceanographic data was collected for a Naval Facilities Engineering Command / Makai project. Results: The model was run for a 100 MW OTEC Plant consisting of four separate ducts, discharging a total combined flow rate of 420 m3/s of warm water and 320 m3/s of cold water in a mixed discharge at 70 meters deep. Each duct was assumed to have a discharge port diameter of 10.5m producing a downward discharge velocity of about 2.18 m/s. The natural system, as measured in the HOTS program, has an average concentration of 10-15 mgC/m3. To calibrate the biological model, we first ran the model with no OTEC plant and varied biological parameters until the simulated data was a good match to the HOTS observations. This modeling showed that phytoplankton concentration were patchy and highly dynamic. The patchiness was a good match with the data variability observed within the HOTS data sets. We then ran the model with simulated OTEC intake and discharge flows and associated nutrients. Directly under the OTEC plant, the near-field plume has an average terminal depth of 172 meters, with a volumetric dilution of 13:1. The average terminal plume temperature was 19.8oC. Nitrate concentrations are 1 to 2 umol/kg above ambient. The advecting plume then further dilutes to less than 1 umol/kg above ambient within a few kilometers downstream, while remaining at depth. Because this terminal near-field plume is well below the 1% light limited depths (~120m), no immediate biological utilization of the nutrients occurs. As the nitrate is advected and dispersed downstream, a fraction of the deep ocean nutrients (< 0.5 umol/kg perturbation) mix upward where they are utilized by the ambient phytoplankton population. This occurs approximately twenty-five kilometers downstream from the plant at 110 - 70 meters depth. For pico-phytoplankton, modeling results indicate that this nutrient perturbation causes a phytoplankton perturbation of approximately 1 mgC/m3 (~10% of average ambient concentrations) that covers an area 10x5 km in size at the 70 to 90m depth. Thus, the perturbations are well within the natural variability of the system, generally corresponding to a 10 to 15% increase above the average pico-phytoplankton biomass. This perturbation exhibits a meandering horizontal plume trajectory and spatial extent, but remains similar in magnitude (generally 1-2 mgC/m3). The diatom perturbations become more noticeable after three weeks of the simulation period, when the nearshore diatom population trends towards a greater concentration of 1 to 3 mgC/m3 . Relative to the background concentrations, this increased response is a fraction of the ambient, with perturbations remaining within fluctuations of the existing system. The perturbations were quantified by post-processing each time-step of model simulations without OTEC plants, with identical simulations that included OTEC plumes. Without this post processing, the 10-25% perturbations were obscured by the larger dynamic variations naturally caused by ocean circulation
Conceptual design appendices A-N (extracted from Hawaii Deep Water Cable Program bottom roughness survey of the Alenuihaha Channel May 1986.)
No full textConceptual design appendices A-N extracted from "Hawaii Deep Water Cable Program Bottom Roughness Survey of the Alenuihaha Channel May 1986.
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Hawaii Deep Water Cable Program : draft cable laying control and data acquisition systems final design report
Get PDFThis report describes the Integrated Control System (ICS), the Data Acquisition System (DAS) and data collection systems presently being completed for the At-Sea Test phase of the Hawaii Deep Wlater Cable Program. Two previous reports on the control of the cable laying process are as follows: "Conceptual Design of Reduced Scale At-Sea Test" - January, 1987 and "Cable Laying Control and Data Acquisitions Systems, Preliminary Design Report"- September 15, 1987. These previous documents provided detailed description of the At-Sea Test and the performance of the cable laying control system. This report is primarily an update of the hardware and the physical description of the system
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