3,522 research outputs found
Occurrence and physical setting of ferromanganese nodules beneath the Deep Western Boundary Current, SW Pacific
No full textAn extensive ferromanganese nodule field adjacent to the Campbell Plateau in the Southwest Pacific Ocean forms beneath the Deep Western Boundary Current (DWBC) and Antarctic Circumpolar Current (ACC). West of c. 174°E, between 59 and 48°S, the field is inferred to be 300–500 km wide, but east of 174°E, where the currents impinge on the eastern slope of the Campbell Plateau, the field narrows from c. 200 km at 55°S to c. 120 km at 49°S. This coincides with deflection of current flow eastward, and consequent reduction in bottom-current velocity and eddy kinetic energy. Based on seafloor photographs, dredge samples, and 3.5 kHz profile data, five principal nodule facies form broadly parallel zones eastwards from the lowermost Campbell escarpment. These are defined based on location, presumed nodule genesis, and seafloor nodule density: (1) slope hydrogenous, high-density (SHH); (2) abyssal diagenetic/hydrogenous, low-density (ADHL); (3) abyssal hydrogenous, high-density (AHH); (4) abyssal diagenetic, high-density (ADH); and (5) abyssal diagenetic, low-density (ADL). Several nodule morphotypes are identified including distinctive discoidal forms with overgrowths possibly resulting from overcrowding and partial sediment burial. Seafloor abundance, surficial textures, and chemistry indicate a predominantly hydrogenous nodule growth and very low net sedimentation beneath the core of the DWBC. Increasing Mn, Ni, and Cu contents, and decreasing detrital silicate contents from core to rim, reflect intensifying abyssal DWBC circulation since c. 6 Ma. Because of the DWBC’s high velocity, the nodules provide no record of an increasing terrigenous bedload from New Zealand since c. 3 Ma. However, in regions of reduced flow velocity eastwards from the main DWBC pathway, relatively higher sedimentation rates prevail, and nodules have a higher diagenetic component
Forced convective heat transfer of 45° rib-roughened fin flows
No full textThe detailed heat transfer measurements in three side-open & bottom-sealed rectangular channels with two opposite walls roughened by 45° full staggered ribs were performed using the infrared radiometer. The present flow configuration simulated an enhanced coolant channel of the fin-type heat-sinks for cooling of electronic chipsets. The hydraulic diameter of three test channels was 14.8 mm with different length-to-gap (L/B) ratios of 21.33, 17.11 & 13.56. The influences of L/B ratio on the local & spatially averaged heat transfers over the rib-roughened surface at Reynolds numbers (Re) of 500, 1000, 2000, 3000 & 3300 were examined. A selection of heat transfer results illustrated the interactive effects between the side-profile leakage-flow & the rib-induced flow phenomena, which were L/B ratio dependent. Heat transfer levels over the rib-roughened surface consistently increased with the increase of Reynolds number or the decrease of L/B ratio. The skewed streamwise ‘‘saw-tooth’’ heat transfer variations gradually emerged over the rib-roughened surface when the Reynolds number systematically increased. Comparing with the heat transfers in the likewise channels but roughened by 90° staggered ribs, the 45° staggered ribs could further enhance heat transfers over 10% for L/B = 21.33 & 50% for L/B = 13.56. Heat transfer correlation for the spatially averaged Nusselt number over a rib-roughened fin surface was generated using Re & L/B ratio as the controlling parameters. A criterion for determining the optimal L/B ratio that could provide the maximum cooling power over a rib-roughened fin surface was subsequently derived to aid the design tools for the heat-sink selection
The Multi-Dimensional Analysis Method Development for KALIMER-600 using MARS-LMR CODE
No full textThis research was supported by KAERI(Korea Atomic Energy Research Institute) and the author would like to thank Dr. S.W. Bae and Dr. K.S. Ha for their help
Improving the performance of the trolley supply chain with a focus on visibility.
No full textThe lack of visibility, significant investment and a presumption of fleet shrinkage falter the decision-making process of a Dutch airline. Five decision areas have been identified and for each decision area improvements strategies or alternatives have been designed. Selecting the best alternative per decision area is a multi-criteria decision making problem. Therefore, a more sophisticated method is required to support the decision-maker. For this problem the novel Best-Worst Multi-Criteria Decision Making Method (BWM) has been selected. The BWM has been successfully applied to select the best alternative per decision area. Next steps for the airline are the implementation of the chosen alternatives.SEPAMTransport & LogisticsTechnology, Policy and Managemen
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