25 research outputs found

    Past 140-year environmental record in the northern South China Sea: Evidence from coral skeletal trace metal variations

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    About 140-year changes in the trace metals in Porites coral samples from two locations in the northern South China Sea were investigated. Results of PCA analyses suggest that near the coast, terrestrial input impacted behavior of trace metals by 28.4%, impact of Sea Surface Temperature (SST) was 19.0%, contribution of war and infrastructure were 14.4% and 15.6% respectively. But for a location in the open sea, contribution of War and SST reached 33.2% and 16.5%, while activities of infrastructure and guano exploration reached 13.2% and 14.7%. While the spatiotemporal change model of Cu, Cd and Pb in seawater of the north area of South China Sea during 1986-1997 were reconstructed. It was found that in the sea area Cu and Cd contaminations were distributed near the coast while areas around Sanya, Hainan had high Pb levels because of the well-developed tourism related activities. (C) 2013 Elsevier Ltd. All rights reserved

    Experimental and theoretical studies of nanofluid thermal conductivity enhancement: a review

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    Nanofluids, i.e., well-dispersed (metallic) nanoparticles at low- volume fractions in liquids, may enhance the mixture's thermal conductivity, knf, over the base-fluid values. Thus, they are potentially useful for advanced cooling of micro-systems. Focusing mainly on dilute suspensions of well-dispersed spherical nanoparticles in water or ethylene glycol, recent experimental observations, associated measurement techniques, and new theories as well as useful correlations have been reviewed

    Photorealistic rendering: a survey on evaluation

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    This article is a systematic collection of existing methods and techniques for evaluating rendering category in the field of computer graphics. The motive for doing this study was the difficulty of selecting appropriate methods for evaluating and validating specific results reported by many researchers. This difficulty lies in the availability of numerous methods and lack of robust discussion of them. To approach such problems, the features of well-known methods are critically reviewed to provide researchers with backgrounds on evaluating different styles in photo-realistic rendering part of computer graphics. There are many ways to evaluating a research. For this article, classification and systemization method is use. After reviewing the features of different methods, their future is also discussed. Finally, dome pointers are proposed as to the likely future issues in evaluating the research on realistic rendering. It is expected that this analysis helps researchers to overcome the difficulties of evaluation not only in research, but also in application

    Effects of a Solar Eclipse on the Propagation of VLF-LF Signals: Observations and Results

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    The results from the measurements of some of the fundamental parameters (amplitude of sferics and transmitted signal, conductivity of lower ionosphere) of the ionospheric responses to the 22 July 2009 solar eclipse (partial: 91.7%) are shown. This study summarizes our results from sferics signals at 81 kHz and subionospheric transmitted signals at 19.8 and 40 kHz recorded at Agartala, Tripura (latitude: 23¢XN, longitude: 91.4¢XE). We observed significant absorption in amplitude of these signals during the eclipse period compared to their ambient values for the same period during the adjacent 7 days. The signal strength along their propagation paths was controlled by the eclipse associated decrease in ionization in the D-region of the ionosphere. Waveguide mode theory calculations show that the elevation of the height of lower ionosphere boundary of the Earth-ionosphere waveguide to a value where the conductivity parameter was 106 unit. The absorption in 81 kHz sferics amplitude is high compared to the absorption in the amplitude of 40 kHz signal transmitted from Japan. The simultaneous changes in the amplitudes of sferics and in the amplitude of transmitted signals assert some sort of coupling between the upper atmosphere and the Earth¡¦s near-surface atmosphere prevailing clouds during solar eclipse

    Effects of the India–Pakistan border earthquake on the atmospherics at 6 kHz and 9 kHz recorded at Tripura

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    <!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables /> <w:SnapToGridInCell /> <w:WrapTextWithPunct /> <w:UseAsianBreakRules /> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if !mso]><object classid="clsid:38481807-CA0E-42D2-BF39-B33AF135CC4D" id=ieooui></object> <mce:style><! st1:*{behavior:url(#ieooui) } --> <!--[endif] --> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> <!--[if gte mso 10]> <mce:style><! /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} --> <!--[endif] -->The unusual variations observed in the records of the integrated field intensity of the atmospherics (IFIA) at 6 kHz and 9 kHz at Agartala, Tripura, in the north-eastern state of India (latitude, 23˚ N; longitude, 91.4˚ E) during the large earthquake on October 8, 2005 at Muzaffarabad (latitude, 34.53˚ N; longitude, 73.58˚ E) in Kashmir in Pakistan are here analyzed. Spiky variations in the IFIA at 6 kHz and 9 kHz were observed several days previous to the day of the earthquake (from midnight, September 28, 2005). The effects persisted for some days, decayed gradually, and eventually ceased on October 31, 2005. The spikes are distinctly superimposed on the ambient level, with mutual separation of 2–5 mins. The number of spikes per day and the total duration of their occurrence were particularly high on the day of the earthquake. The spike heights are higher at 6 kHz than at 9 kHz. The results are discussed here. The generation of electromagnetic radiation associated with the fracture of rocks, the subsequent penetration of this radiation into the Earth atmosphere, and finally its propagation through the Earth–ionosphere waveguide may be responsible for these observed spikes. The present observations show that the very low frequency anomaly dominates between 6 kHz and 9 kHz. The nature of the spikes presented here is a characteristic feature of the IFIA during the period of the earthquake. This has been established on the basis of time-series analyses over a period of one year.<br /><span style="font-size: 12pt;"></span&gt
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