Showing papers by "King Fahd University of Petroleum and Minerals published in 1983"

A study of various factors affecting digestion of fish tissue prior to mercury determination.

Abstract: The effect of temperature on digestion, the acid combination and their quantities, and the time required for digestion of fish tissue were investigated using Hamour (Epinephelus tauvina) body tissue. Concentrations of Hg in fish tissue digested for four hours at 80 +/- 2 degrees C and 95 +/- 2 degrees C were statistically similar and significantly higher than in tissue digested at 60 +/- 2 degrees C. Eight acid combinations were investigated as digestion media and a 1:2 mixture of concentrated HNO3:H2SO4 proved to be the best. A quantity of 15 ml of this digestion media were found to be sufficient to digest approximately two grams of wet fish tissue. The use of 25 ml of digestion media resulted in significantly reduced Hg concentration whereas 10 ml was not sufficient to digest two grams of fish tissue. A digestion period of four to six hours at 80 degrees C was sufficient to oxidize the fish tissue. However, a two hour digestion resulted in reduced Hg values. Mercury determinations made from the samples prepared by the best combination of all the experimental conditions showed a good agreement with those of samples prepared in Teflon Acid Digestion Bombs. This study has pointed the necessity of developing a uniform standard procedure for digesting fish tissue prior to Hg determinations.

The fate of two large oil spills in the arabian gulf

Abstract: In August and October 1980, two large oil spills occurred in the Arabian Gulf. The first, from an unidentified source, involved about 20,000 barrels of crude oil and impacted the entire north and west coasts of the island nation of Bahrain. The second occurred when the Ron Tapmeyer platform in the Hasbah offshore oil field blew out, releasing an estimated 50,000 barrels of thick crude into the Gulf. The spill subsequently covered large sections of the coastline of Qatar. The fate of the oil from these spills is examined with respect to the unique conditions found in the region. A computer model is used for trajectory analysis of the spills and hypothesizing the possible origin of the first spill. Methods of cleanup and problems with the weathered oil are mentioned. The environmental damage caused by the Bahrain spill is assessed.

Complexing of lead by DTPA in calcareous soils

Abstract: Ten agricultural soils were spiked with 100 μg of Cu, Zn, and Pb g−1 of soil The complexation of Pb by 10−4 M DTPA was determined after 60 days of metal equilibrium A theoretical stability model of Fe, Mn, Cu, Zn, Ca, and Pb, between pH 1 and 10 was developed It showed that CuL3− (554 to 63%), CuHL2− (01 to 94%), PbL3− (291 to 333%), PbHL2− (001 to 25%) and MnL3− (28 to 32%) as the predominant species between pH 6 and 9 Other species like CaL3−, CaHL2−, FeL2−, FeHL−, FeL3−, FeHL2−, ZnL3−, ZnHL2− and MnHL2− were less than 01% between pH 6 and 9 In the experimental soils, DTPA-Pb complexes accounted for 123 to 212% of metal complexed after 3 days of DTPA equilibriation DTPA-Cu complexes were the major complexed species in the soils ranging between 725 and 822% after 3 days equilibriation with 10−4 M DTPA The proportion of Zn complexed by DTPA (38 to 101%) was much greater than predicted by the theoretical model On the contrary, Mn was not complexed in appreciable amounts by DTPA

A Surface Renewal/Classical Analysis of Turbulent Convection Heat Transfer*

Abstract: The surface renewal model of wall turbulence is coupled with a classical eddy diffusivity representation of the turbulent core for fully developed, fully turbulent, constant property pipe flow. The analysis provides predictions for velocity and temperature distributions and friction factor and Nusselt number which are compatible with experimental data and standard empirical correlations. Predictions are also developed for em and Pr1 for the inner region which are consistent with recent experimental data. The chief benefits of this approach are felt to include the strong physical basis for the underlying model of wall turbulence, the low level of empiricism, and the potential of generalization. It is hoped that this analysis will provide impetus for formal inclusion of the surface renewal modeling approach in modern numerical computation schemes (including eddy diffusivity, one-equation, or two-equation models for the turbulent core) in analyzing complex turbulent convection heat transfer problems.