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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The prediction of two-phase flows

Papadopoulos, Christos January 1990 (has links)
No description available.
2

Distribution of polycyclic aromatic hydrocarbons (PAHs) in Gao-ping coastal water column

Hsu, Sheng-chieh 29 November 2012 (has links)
Water, suspended particle and sediment samples from Gao-ping coastal water column were collected and measured to determine the spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) during August 2010 and June 2011. In addition, principal component analysis (PCA) and hierarchical the cluster analysis (HCA) were performed with chemical fingerprinting to understand the possible sources of PAHs in Gao-ping coast. The correlations between PAHs and several factors such as salinity, temperature and organic carbon were also discussed in the present study. The total PAH concentrations (dissolved and particulate phase) at four sampling campaigns ranged from 2.09 to 45 ng/L. Concentrations of dissolved PAHs ranged from 2.0 to 39 ng/L and the highest average concentrations were found in November 2010 (10.0 ¡Ó 9.90 ng/L). The particulate PAHs ranged from 0.13 to 40 ng/L and the maximum concentration was found in the estuary in August 2010. The total PAH concentrations of sediment ranged from 125-648 ng/g, which were lower than the Effect Range Low (ERL) and Threshold Effect Level (TEL) values, suggesting that few adverse ecological effects would arise from the PAHs in Gao-ping canyon. Results from chemical fingerprinting, PCA and HCA indicate that PAHs in this area were from complex sources such as combustion, petroleum, diagenesis or biogenic sources. Sources of PAHs in dissolved phase were mainly from petrogenic and mixed sources, while particulate PAHs were mainly from a mixed source. However, sources of PAHs in November 2010 and February 2011 were mostly from mixed combustion, suggesting that the PAH concentrations in particulate phase might be affected by atmospheric transport. The results showed that perylene in Gao-ping coast and canyon was mainly from the biogenic source. A significant correlaction was found in PAH fingerprinting between the esturine particles and sediment, indicating that the sediments in Gao-ping canyon might mainly come from Gao-ping River. Correlation analysis showed a significant positive correlation between concentrations of suspended particle and PAHs, while a negative correlation was found between PAH concentrations and temperature. In addition, organic carbon showed a significant correlation with PAHs in sediment samples. The partition coefficients (Koc) values of PAHs were higher than the values from other literatures, suggesting that it might be attributed to soot carbon.
3

Distribution and sources of polycyclic aromatic hydrocarbons(PAHs) in Er-Jen River

Lin, Chien-ming 22 July 2011 (has links)
In this study our purposes were to investigate the spatial distribution and seasonal variation of polycyclic aromatic hydrocarbons (PAHs) in the dissolved and particulate phase of PAHs in Er-Jen River. In addition, the potential sources of PAHs in Er-Jen River were investigated not only by finger printing, but also principal component analysis (PCA) and hierarchical cluster analysis (HCA). ¡@¡@Concentrations of dissolved and particulate PAHs ranged from 13.8 to 516 ng/L and from 4.05 to 55.9 ng/L, respectively. In March (dry season), concentrations of dissolved and particulate PAHs ranged from 38.3 to 186 ng/L and from 4.05 to 25.9 ng/L, respectively. In addition, concentrations of dissolved and particulate PAHs ranged from 32.3 to 82.8 ng/L and from 14.8 to 85.3 ng/L, respectively in September (wet season). The highest total PAH concentration in this area was found in Station Er-3 which is located on a tributary of Er-Jen River. Total PAH concentrations in wet season were higher than those found in dry season for all stations in Er-Jen River, except for station Er-3, which suggesting that different geography might be the reason. ¡@¡@Results from correlation analysis indicated that distributions of PAH concentrations for particulate phase in Er-Jen River correlated well with flow rate, suspended solid concentrations and salinity. Total PAH concentration of station Er-2, which was located at the downstream Er-Jen River, was highly correlated with salinity; while total PAH concentrations in other stations were mainly affected by flow rate, suspended solid concentrations and some potential sources of pollution. Results from PCA, HCA and finger printing all indicated the origins of PAHs were complex sources in the study area, including pyrogenic, petrogenic and diagenetic/biogenic origins. The origins of PAHs in dissolved phase were mainly from both pyrogenic and petrogenic sources; while those in particulate phase were mainly from pyrogenic sources. In addition, the pyrogenic origins in both dissolved and particulate phase were mostly from liquid fuel combustion. In wet season, howerer, diagenetic/biogenic origins were also found in particulate phase at the sampling sites of Er-Jen River. ¡@¡@The annual total PAH fluxes of Er-Jen River were estimated to be 23.1 kg For dissolved phase, the average daily fluxes in dry and wet season were 5.9 g/day and 65.8 g/day, respectively, with an annual mean fluxe of 11.3 kg/year. For particulate phase, the mean daily fluxes in dry and wet season were 0.8 g/day and 76.2 g/day, respectively, with an annual mean flux of 11.8 kg/year. In general, the total PAH fluxes in wet season were higher than dry season. The total annual PAH fluxes in Er-Jen River were generally less than those reported worldwide, and comparable to those in San Francisco River in USA, but higher than those in Le Havre River in France.

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