The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
B. Mohammed - One of the best experts on this subject based on the ideXlab platform.
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Effects of agrochemicals on surface waters and groundwaters in the Tunga-Kawo (Nigeria) irrigation scheme
Hydrological Sciences Journal, 2003Co-Authors: O. D. Jimoh, M. A. Ayodeji, B. MohammedAbstract:Abstract The Tunga-Kawo Dam has a reservoir capacity of 22 Mm3, and was designed to irrigate 900 ha of land in the Midland region of Nigeria. This paper examines the quality of surface water and groundwater within the scheme. In particular, the seasonal variation of the concentrations of nitrate, phosphate, dissolved oxygen and hydrazine during the year 2000 is discussed. Three sample points: SF1, SF2 and SF3, were selected for monitoring the surface water quality at the upstream, impounded water and Downstream Sections, respectively. The quality of groundwater was monitored using samples from a well near the dam (GW2) and the Downstream Section (GW3). Water samples were taken on a weekly basis from the sample points during the year 2000. It was found that the concentrations in the surface water were higher than the WHO standards for drinking water. For example, the nitrate level in SF3 increased from 0.0 mg l−1 before application of fertilizer to 74.1 mg l−1 after fertilizer was applied, while the phosph...
Yacoubou Salissou - One of the best experts on this subject based on the ideXlab platform.
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an additional configuration to standard astm e2611 09 for measuring the normal incidence sound transmission loss in a modified impedance tube
2012Co-Authors: Olivier Doutres, Raymond Panneton, Yacoubou SalissouAbstract:This paper presents a three-microphone two-load (3M2L) method for measuring the normal incidence sound transmission loss of a noise control system or material in a modified impedance tube. In the standard ASTM E2611-09, the Downstream Section of the impedance tube includes two microphones flush with the interior surface of the tube and the proposed four-microphone two-load (4M2L) method to assess the normal incidence sound transmission loss requires the use of two arbitrary acoustic terminations. The method presented here is conceptually identical but (i) the Downstream Section is reduced to a simple movable rigid backing with one microphone flush mounted on it and (ii) the two arbitrary acoustic terminations are replaced by two air cavities. It thus requires one microphone less and fewer transfer functions. The standard switching technique used to correct the variations between the three microphones is validated on a symmetrical air layer. The proposed 3M2L method is then applied to a non-symmetrical specimen and validated compared to the standard 4M2L method.
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An additional configuration to standard ASTM E2611-09 for measuring the normal incidence sound transmission loss in a modified impedance tube
2012Co-Authors: Olivier Doutres, Raymond Panneton, Yacoubou SalissouAbstract:This paper presents a three-microphone two-load (3M2L) method for measuring the normal incidence sound transmission loss of a noise control system or material in a modified impedance tube. In the standard ASTM E2611-09, the Downstream Section of the impedance tube includes two microphones flush with the interior surface of the tube and the proposed four-microphone two-load (4M2L) method to assess the normal incidence sound transmission loss requires the use of two arbitrary acoustic terminations. The method presented here is conceptually identical but (i) the Downstream Section is reduced to a simple movable rigid backing with one microphone flush mounted on it and (ii) the two arbitrary acoustic terminations are replaced by two air cavities. It thus requires one microphone less and fewer transfer functions. The standard switching technique used to correct the variations between microphones is validated on a symmetrical air layer. The proposed 3M2L method is then applied to a non-symmetrical non-homogenous specimen and validated compared to the standard 4M2L method.
O. D. Jimoh - One of the best experts on this subject based on the ideXlab platform.
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Effects of agrochemicals on surface waters and groundwaters in the Tunga-Kawo (Nigeria) irrigation scheme
Hydrological Sciences Journal, 2003Co-Authors: O. D. Jimoh, M. A. Ayodeji, B. MohammedAbstract:Abstract The Tunga-Kawo Dam has a reservoir capacity of 22 Mm3, and was designed to irrigate 900 ha of land in the Midland region of Nigeria. This paper examines the quality of surface water and groundwater within the scheme. In particular, the seasonal variation of the concentrations of nitrate, phosphate, dissolved oxygen and hydrazine during the year 2000 is discussed. Three sample points: SF1, SF2 and SF3, were selected for monitoring the surface water quality at the upstream, impounded water and Downstream Sections, respectively. The quality of groundwater was monitored using samples from a well near the dam (GW2) and the Downstream Section (GW3). Water samples were taken on a weekly basis from the sample points during the year 2000. It was found that the concentrations in the surface water were higher than the WHO standards for drinking water. For example, the nitrate level in SF3 increased from 0.0 mg l−1 before application of fertilizer to 74.1 mg l−1 after fertilizer was applied, while the phosph...
Hua Meng - One of the best experts on this subject based on the ideXlab platform.
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conjugate heat transfer endothermic fuel pyrolysis and surface coking of aviation kerosene in ribbed tube at supercritical pressure
International Journal of Thermal Sciences, 2018Co-Authors: Keke Xu, Hua MengAbstract:Abstract Supercritical-pressure heat transfer of hydrocarbon fuel plays an important role in regenerative engine cooling in propulsion systems. Conjugate heat transfer, fuel pyrolysis, and surface coking of the aviation kerosene RP-3 in ribbed tubes are numerically studied at a supercritical pressure of 5 MPa, with consideration of detailed pyrolytic chemical reactions. The rib effects on heat transfer, pressure loss, endothermic fuel pyrolysis, and surface coking are comprehensively examined. Results indicate that a ribbed tube is very effective in enhancing heat transfer of a hydrocarbon fuel at supercritical pressure, particularly in the inlet region, in which the tube wall temperature can be reduced by around 300 K. A ribbed tube surface makes significant impacts on fluid temperature distribution and thus fuel pyrolysis. The enhanced heat transfer leads to higher fluid temperature inside a ribbed tube in the Downstream Section, in which strong fuel pyrolysis occurs not only in the near-wall region, as in a smooth tube, but also inside the tube. Therefore, the pyrolytic chemical reaction rate of RP-3 increases in the Downstream Section in a ribbed tube. Owing to the decreased tube wall temperature and decreased species molar concentrations of coking precursors in the near-wall region, pyrolytic surface coking is weakened in a ribbed tube. The thermal performance factor is used to quantify the combined effects of different rib heights on both heat transfer and pressure loss for supercritical-pressure heat transfer of RP-3 in ribbed tubes.
Olivier Doutres - One of the best experts on this subject based on the ideXlab platform.
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an additional configuration to standard astm e2611 09 for measuring the normal incidence sound transmission loss in a modified impedance tube
2012Co-Authors: Olivier Doutres, Raymond Panneton, Yacoubou SalissouAbstract:This paper presents a three-microphone two-load (3M2L) method for measuring the normal incidence sound transmission loss of a noise control system or material in a modified impedance tube. In the standard ASTM E2611-09, the Downstream Section of the impedance tube includes two microphones flush with the interior surface of the tube and the proposed four-microphone two-load (4M2L) method to assess the normal incidence sound transmission loss requires the use of two arbitrary acoustic terminations. The method presented here is conceptually identical but (i) the Downstream Section is reduced to a simple movable rigid backing with one microphone flush mounted on it and (ii) the two arbitrary acoustic terminations are replaced by two air cavities. It thus requires one microphone less and fewer transfer functions. The standard switching technique used to correct the variations between the three microphones is validated on a symmetrical air layer. The proposed 3M2L method is then applied to a non-symmetrical specimen and validated compared to the standard 4M2L method.
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An additional configuration to standard ASTM E2611-09 for measuring the normal incidence sound transmission loss in a modified impedance tube
2012Co-Authors: Olivier Doutres, Raymond Panneton, Yacoubou SalissouAbstract:This paper presents a three-microphone two-load (3M2L) method for measuring the normal incidence sound transmission loss of a noise control system or material in a modified impedance tube. In the standard ASTM E2611-09, the Downstream Section of the impedance tube includes two microphones flush with the interior surface of the tube and the proposed four-microphone two-load (4M2L) method to assess the normal incidence sound transmission loss requires the use of two arbitrary acoustic terminations. The method presented here is conceptually identical but (i) the Downstream Section is reduced to a simple movable rigid backing with one microphone flush mounted on it and (ii) the two arbitrary acoustic terminations are replaced by two air cavities. It thus requires one microphone less and fewer transfer functions. The standard switching technique used to correct the variations between microphones is validated on a symmetrical air layer. The proposed 3M2L method is then applied to a non-symmetrical non-homogenous specimen and validated compared to the standard 4M2L method.