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51.
The cumulative effect of accidental spills from oil and gas extraction in the marine environment can have significant impacts on marine wildlife. Oil and gas operators are typically required to report spill data as part of a regulatory process. We conducted a survey of the public disclosure of hydrocarbon spill data for four countries, Australia, Canada, United Kingdom and United States. There was significant variation in the spill data statistics that were publicly reported by the regulators. No country provided full disclosure of spill data or follow-up actions taken by the regulator on their website. The lack of disclosure of spill data is of concern because the scale of environmental effects is more difficult to assess, insufficient information is available to assess the accuracy of predictions made in the environmental assessment process, and without consistency of spill reporting there is no method to compare regional differences of spill rates. 相似文献
52.
This paper presents a detailed account of the effect of shipping activity on the increasing trends of air temperatures in the Canadian Arctic region for the period of 1980–2018. Increasing trend of temperature has gained significant attention with respect to shipping activities and sea ice area in the Canadian Arctic. Temperature, sea ice area and shipping traffic datasets were investigated, and simple linear regression analyses were conducted to predict the rate of change(per decade) of the average temperature, considering winter(January) and summer(July) seasons. The results indicate that temperature generally increased over the studied region. Significant warming trend was observed during July, with an increase of up to 1℃, for the Canadian Arctic region. Such increasing trend of temperature was observed during July from the lower to higher latitudes. The increase in temperature during July is speculated to increase the melting of ice. Results also show a decline in sea ice area has a significant positive effect on the shipping traffic, and the numbers of marine vessel continue to increase in the region. The increase in temperature causes the breaking of sea ice due to shipping activities over northern Arctic Canada. 相似文献
53.
Asim Jilani Syed Zajif Hussain Mohd Hafiz Dzarfan Othman Usama Zulfiqar Muhammad Bilal Shakoor Imran Ullah Khan Javed Iqbal Attieh A. Al-Ghamdi Ahmed Alshahrie 《Journal of Atmospheric Chemistry》2018,75(3):271-283
In this work, the X-ray Photoelectron Spectroscopy (XPS) technique is utilized to analyze the surface chemical composition of particulate matter (PM) which was collected from various locations at Jeddah, Saudi Arabia. The main elements found on the surface of PM are carbon (C), oxygen (O) and silicon (Si) with combined percentage of 89.4–94.9 while traces of nitrogen (N), calcium (Ca), aluminum (Al), sodium (Na), chlorine (Cl), manganese (Mg), and sulfur (S) were also present. The analyzed XPS chemical state of C, O and Si was further used to determine their bonding with other elements occurring over the surface of PM. Carbon was found in the form of carbides (18.86%), fluorides (2.39%) and carbonates (78.75%); oxygen was observed as oxides (21.05%) and hydroxides (73.42%) of other metals; and silicon was detected as silicones (12.16%), nitrides (82.53%) and silicates (5.25%). The particle size of a PM is also of great concern for health issues, and thus has been investigated by the Field Emission Scanning Electron Microscope (FESEM). The Energy Dispersive X-ray Spectroscopy (EDS) was employed for cross verification of detected elements by XPS. 相似文献
54.
N. Hussain 《Journal of Earth System Science》1991,100(1):1-11
A simple thermal model is developed to evaluate the heat exchange surface area of a hot dry rock geothermal reservoir. This
model, in conjunction with the Rn model of Andrews and coworkers, is applied to RH12/RH15 system of the British HDR reservoir.
Results suggest that although the estimated Rn transfer surface area represents the actual swept surface area, it is between
25 and 45 times larger than the heat transfer surface area. The difference is explained as due to clustering of several fractures
within a range of thermal interaction, over the duration of the circulation. It is also shown that the decline in the measured
temperatures of circulation fluids since 1985 to the present is consistent with the heat exchange surface area going through
a maximum in 1987. 相似文献
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Ortho- and para-amphibolites occur throughout the Dharwar schists, gneisses and ultramafics in Karnataka State, India. From the chemical data alone, these ortho- and para-amphibolites cannot be very clearly differentiated. While the ortho-amphibolites follow the Karroo trend, the para-amphibolites appear to have been evolved from the metamorphism of low-Si and -K graywackes. The amphibolitic xenoliths occurring in Peninsular gneisses follow both the igneous and graywacke field, indicating that probably both para and ortho types constitute these enclaves. Their trace element concentrations, like those of Ni, Co and Cr, are not related to the Mg and Fe contents of the amphibolites. Probably these amphibolites have been derived from basic rocks, which were predominant over the Archaean crust, either directly or after having gone through a sedimentary cycle. The higher concentration of Ni, Co, Cr and other elements, such as Mg, in these amphibolites, as compared with younger oceanic basalts, thus indicates the higher concentration of these elements in Archaean basalts and the proto-mantle. 相似文献
60.
Mathematical relationships have been developed for reaeration rate coefficient (Ka) by various researchers. These relationships have a number of variables such as depth, velocity, width, slope, Froud number, molecular diffusion coefficient, kinematic viscosity and the gas‐transfer Reynolds number. From these variables, 29 relations have been developed and divided into four groups. To evaluate their predictive capability for highly variable flow rivers receiving high pollution loads form large cities, these relationships have been used to model dissolved oxygen (DO) in the River Ravi. Such rivers are either saturated with DO during high flows or anaerobic during critical low‐flow conditions. The evaluation is based on the agreement between model DO values calculated using Ka obtained from the available equations and the measured DO concentrations in the river samples in terms of sum of square of residuals (SSR) and coefficient of determination (R2). It has been found that in general, the group of equations containing depth and velocity as the only two variables affecting Ka performed better than the equations in other groups as reflected by lower SSR and higher R2 values. The study results also reveal that the turbulence‐based reaeration rate coefficient equation containing additional variables also resulted in close agreement between DO model results and the measured values. The study results identify the most important parameters affecting the reaeration rate coefficient and the suitability of various Ka relationships as well for rivers with highly variable flows. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献