| 1. |
- Al Maliki, Ali, et al.
(författare)
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Comparison between inductively coupled plasma and X-ray fluorescence performance for Pb analysis in environmental soil samples
- 2017
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Ingår i: Environmental Earth Sciences. - : Springer. - 1866-6280 .- 1866-6299. ; 76:12
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Tidskriftsartikel (refereegranskat)abstract
- Comparison of two conventional analytical techniques such as X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) for measuring Pb concentrations in soil samples was achieved using field and laboratory work. Seventy-three samples were collected from urban areas surrounding the large lead smelter at South Australia, as an indicator of the environment impact of smelter activity. Soil Pb concentrations were determined using hand-held XRF analyser under laboratory conditions. ICP-MS analysis on digested soils (using a microwave-assisted nitric acid digestion-extraction) was applied to validate p-XRF data. The analysis showed that Pb concentrations determined by XRF correlated with high linearity with Pb concentrations determined by ICP-MS measurements (R2 = 0.89). Statistical test (t test) was applied to the data of both methods applied without any significant difference between the two techniques. These results indicated that ICP-MS corroborated XRF for Pb soil measurements and suggests that XRF was a reliable and quick alternative to traditional analytical methods in studies of environmental health risk assessment, allowing for much larger sampling regimes in relatively shorter times and could be applied in the field.
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| 2. |
- Al-Hashimi, Shaymaa A.M., et al.
(författare)
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Flow over Broad Crested Weirs: Comparison of 2D and 3D Models
- 2017
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Ingår i: Journal of Civil Engineering and Architecture. - : David Publishing Company. - 1934-7359 .- 1934-7367. ; 11:8, s. 769-779
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Tidskriftsartikel (refereegranskat)abstract
- The flow over broad-crested weirs was simulated by computational fluid dynamic model. The water surface profile over broad crested weir was measured in a laboratory model and validated using two and three dimensional Fluent programs. The Reynolds Averaged Navier-Stokes equations coupled with the turbulent standard (k-ε) model and volume of fluid method were applied to estimate the water surface profile. The results of numerical model were compared with experimental results to evaluate the ability of model in describing the behaviour of water surface profile over the weir. The results indicated that the 3D required more time in comparison with 2D results and the flow over weir changed from subcritical flow at the upstream (U/S) face of weir to critical flow over the crest and to supercritical flow at downstream (D/S). A reasonable agreement was noticed between numerical results and experimental observations with mean error less than 2 %.
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| 3. |
- Al-Jabban, Wathiq, et al.
(författare)
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Modification-Stabilization of Clayey Silt Soil Using Small Amounts of Cement
- 2017
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 7:3, s. 77-96
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the effects of using a small percentage of cement to stabilize clayey silt with a low organic content. Cement was added at percentages of 1, 2, 4 and 7% by dry weight. The physical and mechanical properties of the treated and untreated soil were evaluated by laboratory tests including tests of consistency limits, unconfined compressive strength, soil density, solidification and pH values. These tests have been conducted after 7, 14, 28, 60 and 90 days of curing time. Workability is defined as how easily the soil can be control or to handle physically. Results showed that the engineering properties of the clayey silt were improved. The soil exhibited better workability directly after treatment, and the workability increased with time. Soil density increased, while water content decreased, with increasing cement content and longer curing time. The pH value was immediately raised to 12 after adding 7% cement content, and then it gradually decreased as curing time increased. An increase of unconfined compressive strength and stiffness was observed, while strain at failure decreased. A gradual change in failure mode from ductile behavior to brittle failure was observed. The findings are useful when there is a need for modification and stabilization of clayey silt in order to increase the possibilities for different use which will reduce transportation and excavation.
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| 4. |
- Al-Jabban, Wathiq, et al.
(författare)
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Stabilization of Clayey Silt Soil Using Small Amounts of Petrit T
- 2017
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Ingår i: Engineering. - : Scientific Research Publishing. - 1947-3931 .- 1947-394X. ; 9:6, s. 540-562
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Tidskriftsartikel (refereegranskat)abstract
- Effects of using small amounts of a Petrit T, a by-product of manufacture sponge iron, to modify clayey silt soil were investigated in this study. Petrit T was added at 2%, 4% and 7% of soil dry weight. A series of unconfined compressive strength tests, consistency limits tests and pH tests were conducted at 7, 14, 28, 60 and 90 days of curing periods to evaluate the physical and mechanical properties of treated soil. Results indicated improving in the unconfined compressive strength, stiffness and workability of treated soil directly after treatment and over time. Increasing in soil density and decreasing in water content were observed, with increasing Petrit T content and curing time. The pH value was immediately increasing after treatment and then gradually decreased over time. Failure mode gradually changed from plastic to brittle behavior with increasing binder content and curing time. The outcomes of this research show a promising way of using a new by-product binder to stabilize soft soils in various engineering projects in order to reduce the costs which are associated with of excavation and transportation works.
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| 5. |
- Al-Madhlom, Qais, et al.
(författare)
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Seepage Velocity of Dibdibba Formation in Karbala, Iraq
- 2017
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Ingår i: Engineering. - : Scientific Research Publishing. - 1947-3931 .- 1947-394X. ; 9:3, s. 279-290
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Tidskriftsartikel (refereegranskat)abstract
- Iraq highly depends on its surface water resources. Now it is facing water shortage problems. For these reasons, the utilization of groundwater will be increasing with time. Karbala Governorate is located in the central part of Iraq. It covers an area of 5034 km2 and the population exceeds one million. It is characterized by an arid or semiarid environment. Karbala Governorate lack surface water resource and consequently, groundwater is the only available resource. The main groundwater aquifer within the area is Dibdibba formation. It is composed of poorly sorted sand and sand stone with gravel. In this research hydrological and hydrogeological information were used to find out the magnitude and the direction of groundwater seepage velocity. The results indicate that groundwater flow toward the flood plain to the east of the study region. The seepage velocity ranges from 0 to 0.18 m/d, with a general increase when moving from the west to the east.
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| 6. |
- Ali, Ammar A., et al.
(författare)
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Spatial Measurement of Bed Load Transport in Tigris River
- 2017
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - London : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 7:4, s. 55-75
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Tidskriftsartikel (refereegranskat)abstract
- Using Helley-Smith sampler, 288 bed load samples were collected from 16 cross sections along 18 km reach length of Tigris River within Baghdad. The spatial distribution of sampling along the reach took into consideration the variance of river topography where 7 meanders, 2 islands and several bank depositions characterize the geometry of the river. The implemented regulation schemes on Tigris River have reduced 44% of water discharges compared to previous period. The spatial variance in topography was effectively scattering the results of the applied twenty bed load formulas. The study results indicated that the complicated geometry of the river reach makes finding a unique representative bed load formula along the study reach rather difficult, and there is no grantee to have good agreement with measurements in the irregular cross sections (meanders, sand bars, etc.). The closest bed load prediction formulas were van Rijn1984. The annual transported quantities of bed load were estimated to be 30 thousand tons (minimum) in 2009 and 50 thousand tons (maximum) in 2013.
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| 7. |
- Ali, Ammar, et al.
(författare)
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Three-Dimensional Morphodynamic Modelling of TigrisRiver in Baghdad
- 2017
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Ingår i: Journal of Civil Engineering and Architecture. - : David Publishing Company. - 1934-7359 .- 1934-7367. ; 11:6, s. 571-594
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Tidskriftsartikel (refereegranskat)abstract
- Bathymetric and land surveys were conducted for the northern Tigris River reach (18 km length) in Baghdad, producing 180cross sections. A river bed topography map was constructed from these cross sections. The velocity profiles and the water discharges were measured using ADCP (Acoustic Doppler Current Profiler) at 16 cross sections, where intensive number of sediment samples was collected to determine riverbed characteristics and sediment transport rate. The three-dimensional morphodynamic model (SSIIM (simulation of sediment movements in water intakes with multiblock option)) was used to simulate the velocity field and the water surface profile along the river reach. The model was calibrated for the water levels, the velocity profiles and the sediment concentration profiles using different combinations of parameters and algorithms. The calibration and the validation results showed good agreement with field measurements, and the model was used to predict the future changes in river hydro-morphology for a period of 14 months. The results of the future predictions showed the Tigris River which behaved like an under-fit river, increases in depositions on the shallow part of the cross section having lower velocity, and the river deepens the incised route to fit its current hydrologic condition leaving the former wide section as a floodplain for the newer river. The net deposition/erosion rate was 67.44 kg/s in average and the total deposition quantity was 2.12 million ton annually. An expansion in the size of current islands was predicted. An indication of thepotential threats of the river banks’ collapse and the bridge piers’ instability was given by high erosion along the thalweg line.
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| 8. |
- Abbas, Nahlah, et al.
(författare)
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Impacts of Climate Change on Water Resources of Greater Zab and Lesser Zab Basins, Iraq, Using Soil and Water Assessment Tool Model
- 2017
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Ingår i: International Journal of Environmental, Chemical, Ecological, Geological and Geophysical Engineering. - : World Scientific and Engineering Academy and Society. - 2010-376X .- 2010-3778. ; 11:10, s. 823-829
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Tidskriftsartikel (refereegranskat)abstract
- The Greater Zab and Lesser Zab are the major tributaries of Tigris River contributing the largest flow volumes into the river. The impacts of climate change on water resources in these basins have not been well addressed. To gain a better understanding of the effects of climate change on water resources of the study area in near future (2049-2069) as well as in distant future (2080-2099), Soil and Water Assessment Tool (SWAT) was applied. The model was first calibrated for the period from 1979 to 2004 to test its suitability in describing the hydrological processes in the basins. The SWAT model showed a good performance in simulating streamflow. The calibrated model was then used to evaluate the impacts of climate change on water resources. Six general circulation models (GCMs) from phase five of the Coupled Model Intercomparison Project (CMIP5) under three Representative Concentration Pathways (RCPs) RCP 2.6, RCP 4.5, and RCP 8.5 for periods of 2049-2069 and 2080-2099 were used to project the climate change impacts on these basins. The results demonstrated a significant decline in water resources availability in the future.
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| 9. |
- Abbas, Nahla, et al.
(författare)
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The Impacts of Climate Change on Fitzroy River Basin, Queensland, Australia
- 2017
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Ingår i: Journal of Civil Engineering and Architecture. - USA : David Publishing Company. - 1934-7359 .- 1934-7367. ; 11:1, s. 38-47
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Tidskriftsartikel (refereegranskat)abstract
- An analysis of historical data of Fitzroy River, which lies in the east coast of Australia, reveals that there is an increasing trend in extreme floods and droughts apparently attributable to increased variability of blue and green waters which could be due to climate change. In order to get a better understanding of the impacts of climate change on the water resources of the study area for near future as well as distant future, SWAT (soil and water assessment tool) model was applied. The model is first tested for its suitability in capturing the basin characteristics with available data, and then, forecasts from six GCMs (general circulation model) with about half-a-century lead time to 2046~2064 and about one-century lead time to 2080~2100 are incorporated to evaluate the impacts of climate change under three marker emission scenarios: A2, A1B and B1. The results showed worsening water resources regime into the future.
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| 10. |
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