Geo-engineering evaluation of Harrat Irbid Basaltic Rocks,Irbid District—North Jordan     

Israa?S.?Abu-MahfouzEmail authorView author&#;s OrcID profile  Ahmad?A.?Al-Malabeh  Shaher?M.?Rababeh 《Arabian Journal of Geosciences》2016,9(5):412

The basalt flow in Irbid district covers an area of about 300 km² and forms different shapes: elongated strips, sub-rounded spots, and arc-like outcrops. The basalt flow in the study area has thicknesses ranging from 1 to 30 m. This study is conducted to evaluate the basaltic rocks as a construction material in eight different places of Harrat Irbid. Thirty-six rock cores were prepared from the collected fresh basaltic rock samples to study the physical and mechanical properties. The basaltic rocks in the study area have desirable physical and mechanical properties; the rocks have high apparent specific gravity values (2.70–2.90), bulk specific gravity (2.60–2.84), absorption values (0.33–1.60 %) that indicates the texture is crystalline, porosity (0.22–2.15 %), void ratio (0.002–0.022), water content (0.35–1.08 %), degree of saturation (41–68 %), rebound number of Schmidt hammer hardness test (average 44.10), point load strength(average 11.35 MPa),uniaxial strength (average 106.83 MPa) which is classified as medium strength, basalt uniformity of wear (0.206), and very high durability which is equal to 99.52 % in average, recorded after the second cycle of the test. Based on field observations and physical and mechanical tests, this study confirms that the genesis of basalt in the study area is strongly related to Harrat Al-Shaam basalt. Therefore, this study adds a new area of about 300 km² to the Harrat Al-Shaam area. Additionally, this study strongly recommends the use of the basaltic rocks that have been tested in this study for some industrial applications (e.g., in construction).  相似文献   

Spatial evaluation of impacts of increase in impervious surface area on SCS-CN and runoff in Nagpur urban watersheds,India     

Tauseef Ahmad Ansari  Yashwant B. Katpatal  A. D. Vasudeo 《Arabian Journal of Geosciences》2016,9(18):702

The changing land use due to rapid urbanization has profound impact on the runoff in urban watersheds. The spatial analysis in urban watersheds is felt necessary for management of surface and subsurface water regimes. Significant increase in impervious zones was observed in Nagpur urban watersheds between 2000 and 2012 having impacts on runoff, and even flash floods were observed. This study presents spatial and temporal impacts of change in urban built-up area on curve number (CN) and runoff during the years 2000 and 2012. The study also analyzes effect of slope on CN values and shows that CN increases with slope. High-resolution satellite images were used to map impervious surface areas (ISAs) which show an increase of 0.9 to 34 % during 2000–2012. Spearman’s and Pearson’s coefficients have been generated to establish relationship between runoff, impervious surface areas, vegetation index, slope, and runoff coefficient. It has been hypothetically assumed that if 100, 50, and 25 % rooftop rainwater harvesting is considered, the estimated runoff reduces in 2012 as compared to the year 2000. The study suggests that increase in impervious areas within urban watersheds can be utilized for groundwater augmentation adopting rooftop rainwater-harvesting techniques and to prevent flash floods.  相似文献   

Occurrence of natural radioactivity and corresponding health risk in groundwater with an elevated radiation background in Juban District,Yemen     

Wedad Ali Abdurabu  Muneer Aziz Saleh  Ahmad Termizi Ramli  Arien Heryansyah 《Environmental Earth Sciences》2016,75(20):1360

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Criteria of Acceptance for Constant Rate of Strain Consolidation Test for Tropical Cohesive Soil     

Khairul Anuar Kassim  Ahmad Safuan A. Rashid  Ahmad Beng Hong Kueh  Chong Siaw Yah  Lam Chee Siang 《Geotechnical and Geological Engineering》2016,34(4):931-947

In this study, the rapid consolidation equipment (RACE) was developed as an alternative device to the conventional consolidation test using Oedometer, consuming merely a few hours for the whole precedure to determine the consolidation characteristics of cohesive soil. RACE operates based on the constant rate of strain (CRS) consolidation theory, which is a continuous loading method of testing, requiring a good estimation of the loading rate such that it is ideal for the achievement of steady state condition during testing. The steady state condition is achieved when the c _v values from drained and undrained face of CRS converged with the c_v from Oedometer test. A slightly modification has been made on the normal constant rate of strain (CRS) test by proposing a direct back pressure system to the specimen using a tube to saturate the soil sample. This research has produced a set of criteria for determining the suitable rate for the rapid consolidation test based on the ratio of normalized strain rate, β, and proposed a new coefficient in terms of a ratio of β to clay fraction (CF), as a part of new criteria for testing a fine soil. Four types of sample were tested with different rates of strain using the RACE and their results were compared with those conducted using the Oedometer on the same soil type, from which fairly good agreements were evident in many specimens. It was found from the study that the minimum value of normalized strain rate, β, for the CRS test is 0.005 and for the u _a /σ _v ratio is suggested as 0.01. Also, the maximum β/CF for soils with clay friction lower and higher than 50 % are 0.008 and 0.001, respectively. The minimum β/CF value for both conditions is 0.0001.  相似文献   

Uncertainty Analysis of Wind-Wave Predictions in Lake Michigan     

Navid NEKOUEE  Behzad ATAIE-ASHTIANI  Sajad Ahmad HAMIDI 《海洋工程》2016,(5):811-820

With all the improvement in wave and hydrodynamics numerical models, the question rises in our mind that how the accuracy of the forcing functions and their input can affect the results. In this paper, a commonly used numerical third-generation wave model, SWAN is applied to predict waves in Lake Michigan. Wind data are analyzed to determine wind variation frequency over Lake Michigan. Wave predictions uncertainty due to wind local effects are compared during a period where wind has a fairly constant speed and direction over the northern and southern basins. The study shows that despite model calibration in Lake Michigan area, the model deficiency arises from ignoring wind effects in small scales. Wave prediction also emphasizes that small scale turbulence in meteorological forces can increase prediction errors by 38%. Wave frequency and coherence analysis show that both models can predict the wave variation time scale with the same accuracy. Insufficient number of meteorological stations can result in neglecting local wind effects and discrepancies in current predictions. The uncertainty of wave numerical models due to input uncertainties and model principals should be taken into account for design risk factors.  相似文献   

Erratum to: Application of extreme learning machine for estimation of wind speed distribution     

Shahaboddin Shamshirband  Kasra Mohammadi  Chong Wen Tong  Dalibor Petković  Emilio Porcu  Ali Mostafaeipour  Sudheer Ch  Ahmad Sedaghat 《Climate Dynamics》2016,46(5-6):2025-2025

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Investigation on the Distribution of Gold Across the Ahar Area (NW Iran) Using Stream‐Sediment and BLEG Methods          下载免费PDF全文

Vartan Simmonds  Fatemeh Jahangiryar  Mohssen Moazzen  Ahmad Ravaghi 《Resource Geology》2016,66(2):213-225

The Ahar area is located in NW Iran. The main part of the area is covered by Eocene andesitic and andesi‐basaltic rocks within which several granitoid intrusives of Oligocene age are emplaced. This caused vast hydrothermal alterations and Cu and Au mineralization. In this regard, this contribution aims to explore the distribution of gold across the region based on systematic sampling of stream sediments and using the secondary geochemical halos, as well as the bulk leach extractable gold (BLEG) method. Meanwhile, the results obtained from these two methods will be compared in order to find out if the anomalous zones match with each other. For this, 620 stream sediment samples of ?80 mesh grain size and 422 BLEG samples were collected and analyzed by Fire Assay and atomic absorption spectroscopy (AAS) methods, respectively. For BLEG samples, gold was first dissolved using KCN before being analyzed by the AAS method. Furthermore, 84 rock samples were also collected during the field control surveys and were analyzed by Fire Assay and ICP‐OES methods for gold and other elements, respectively. After determining the distribution characteristics and statistical parameters of gold in each group of samples, anomaly maps of gold for each method were prepared, revealing almost similar anomalous zones across the region. Based on these maps, most of the discovered anomalies correlate well with granitoid intrusives of Oligocene age and the related hydrothermal alterations, which have occurred within the intrusives and the host andesitic‐basaltic rocks of Eocene age, especially at the NE and central parts of the area and east of Ahar. Some silicic veins and veinlets have been observed during field surveys in these parts, within which high concentrations of Au and sometimes Cu are determined. Another anomalous zone is located over the hydrothermal alterations within trachy‐andesitic and andesitic volcanics of Pliocene age at the SE part of the quadrangle, where vast alterations caused by volcanic fumaroles and epithermal mineralization of gold and Pb–Zn is discovered. In this regard, the SE and NE parts of the area and the east Ahar area are proposed, in order of importance, for further detailed investigations.  相似文献   

Assessing changes in the above ground biomass and carbon stocks of Lidder valley,Kashmir Himalaya,India   总被引：1，自引：0，他引：1  

Irfan Rashid  Mudasir Ahmad Bhat  Shakil Ahmad Romshoo 《国际地球制图》2017,32(7):717-734

The changes in the land use and land cover (LULC), above ground biomass (AGB) and the associated above ground carbon (AGC) stocks were assessed in Lidder Valley, Kashmir Himalaya using satellite data (1980–2013), allometric equations and phytosociological data. Change detection analysis of LULC, comprising of eight vegetation and five non-vegetation types, indicated that 6% (74.5 km²) of the dense evergreen forest has degraded. Degraded forest and settlement increased by 20 and 52.8 km², respectively. Normalized difference vegetation index was assessed and correlated with the field-based biomass estimates to arrive at best-fit models for remotely sensed AGB estimates for 2005 and 2013. Total loss of 1.018 Megatons of AGB and 0.5 Megatons of AGC was estimated from the area during 33-year period which would have an adverse effect on the carbon sequestration potential of the area which is already facing the brunt of climate change.  相似文献   

Litter pollution on the Jordanian shores of the Gulf of Aqaba (Red Sea)   总被引：1，自引：0，他引：1  

Abu-Hilal AH  Al-Najjar T 《Marine environmental research》2004,58(1):39-63

Litter was assessed on three beaches along the Jordanian coast of the Gulf of Aqaba, south of the town Aqaba, monthly during 1994 and 1995, in order to determine its nature, extent and possible sources. The overall mean was about 5 and 3 items/m(2) in 1994 and 1995, respectively. Approximately a total of 14,000 m(2) were examined and a total of 101,000 items were noted, 67,000 during 1994 and 34,000 in 1995. More than 50% of the litter was plastic and the remainder wood, glass, cardboard, Styrofoam, metal and other materials. Most litter appears to be from local land-based or near shore sources, although there are some regional influences as well. The main local sources are the passenger port, the cargo port and the beach goers. The findings are compared with other regions of the world. The amount of litter is related to distance of the beach from the main sources, and shape, physiography and orientation of the beach. Spatial and seasonal variations are examined and discussed, and actions and measures to combat the problem on local and regional levels are suggested.  相似文献   

Assessing the potential of two typical layered complexes from the Arabian Shield for hosting Ni-Cu mineralization through stream sediment geochemistry     

Ahmad M. Al-Saleh 《Arabian Journal of Geosciences》2016,9(6):470

Two late Proterozoic (< 630 Ma) mafic layered complexes (Al-Jilani and Shai) from the central and southern Arabian Shield were chosen for a preliminary rock and stream sediment survey to test their potential for hosting Ni–Cu sulfide mineralization. The choice was made on the basis of the highly differentiated and exceptionally well-layered nature of these intrusives, with the ultimate aim of drawing inferences on the mineralization potential of other mafic bodies of the same age and setting. The results showed a marked depletion of the target elements and their pathfinders (Ni, Cu, Co, Cr, and PGE), except for a single anomalous location at Shai which appears to lithologically induced rather than representing a true sulfide signature. The two major problems in the stream sediment results were the masking effect from the host lithologies and the dilution by felsic detritus. Applying factor analysis to the data set failed to yield an “ore factor” that excludes mafic lithophile elements, but revealed the important role of the Fe–Mn oxyhydroxides in adsorbing certain metal cations even in the arid climate of the Arabian Shield, thus opening up the possibility of future work utilizing partial leach techniques in this part of the world. Overall, the two complexes do not seem to satisfy the necessary requirements for Ni–Cu sulfide enrichment in that there is a general lack of an external source of sulfur, in addition to the absence of a concentration mechanism for any produced sulfides.  相似文献