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Kaye Nigel B. Robinson Dylan M. Akhter Romana Ahsanullah Md Safwan Jordan TaJon A. Martinez Oscar E. 《Environmental Fluid Mechanics》2022,22(4):763-787
Environmental Fluid Mechanics - Buoyant turbulent plumes are often categorized by their geometry and described as either round plumes, issuing from a point source, or line/planar plumes, issuing... 相似文献
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Asam Farid Khanzaib Jadoon Gulraiz Akhter Muhammad Asim Iqbal 《Environmental monitoring and assessment》2013,185(3):2407-2422
Hydrostratigraphy and hydrogeology of the Maira vicinity is important for the characterization of aquifer system and developing numerical groundwater flow models to predict the future availability of the water resource. Conventionally, the aquifer parameters are obtained by the analysis of pumping tests data which provide limited spatial information and turn out to be costly and time consuming. Vertical electrical soundings and pump testing of boreholes were conducted to delineate the aquifer system at the western part of the Maira area, Khyber Pakhtun Khwa, Pakistan. Aquifer lithology in the eastern part of the study area is dominated by coarse sand and gravel whereas the western part is characterized by fine sand. An attempt has been made to estimate the hydraulic conductivity of the aquifer system by establishing a relationship between the pumping test results and vertical electrical soundings by using regression technique. The relationship is applied to the area along the resistivity profiles where boreholes are not drilled. Our findings show a good match between pumped hydraulic conductivity and estimated hydraulic conductivity. In case of sparse borehole data, regression technique is useful in estimating hydraulic properties for aquifers with varying lithology. 相似文献
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Akil Ahm Jamal Akhter Siddique Mohammad Asaduddin Laskar Rajeev Kumar Siti Hamidah Mohd-Setapar Asma Khatoon Rayees Ahmad Shiekh 《环境科学学报(英文版)》2015,27(5):104-123
The direct determination of toxic metal ions, in environmental samples, is difficult because of the latter's presence in trace concentration in association with complex matrices, thereby leading to insufficient sensitivity and selectivity of the methods used. The simultaneous removal of the matrix and preconcentration of the metal ions, through solid phase extraction, serves as the promising solution. The mechanism involved in solid phase extraction (SPE) depends on the nature of the sorbent and analyte. Thus, SPE is carried out by means of adsorption, ion exchange, chelation, ion pair formation, and so forth. As polymeric supports, the commercially availableAmberlite resins have been found very promising for designing chelating matrices due to its good physical and chemical properties such as porosity, high surface area, durability and purity. This review presents an overview of the various works done on the modification of Amberlite XAD resins with the objective of making it an efficient sorbent. The methods of modifications which are generally based on simple impregnation, sorption as chelates and chemical bonding have been discussed. The reported results, including the preconcentration limit, the detection limit, sorption capacity, preconcentration factors etc., have been reproduced. 相似文献
15.
Assessment of strontium and calcium levels in Pakistani diet 总被引:1,自引:0,他引:1
Akhter P Baloch NZ Mohammad D Orfi SD Ahmad N 《Journal of environmental radioactivity》2004,73(3):247-256
To cope with nuclear emergency effectively due to ingestion of fission fragment (90)Sr, adequacy of nutritionally and radiologically important elements strontium and calcium was studied in typical Pakistani diet and baseline analytical data were generated. Concentrations of strontium and calcium were measured by using inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and atomic absorption spectrometry (AAS) techniques. Daily dietary intake of strontium and calcium varied from 0.9 to 5.7 mg and 217 to 713 mg with the geometric mean value x geometric standard deviation of 2.6 x 1.7 and 487.1 x 1.4 mg d(-1), respectively. The average Sr concentration in the Pakistani diet was 1.4 times higher while Ca concentration was 0.4 times lower than the recommended values of the International Commission on Radiological Protection (ICRP). The calculated Sr/Ca ratio 5.3E-03 was also higher than the ICRP value. The study depicts that the strontium concentration in the Pakistani diet is adequate, while the calcium concentration is inadequate according to international standards and needs improvement. 相似文献
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Morgubatul Jannat Mohammed Kamal Hossain Mohammad Main Uddin Md. Akhter Hossain Md. Kamruzzaman 《国际发展与全球生态学杂志》2018,25(6):554-561
The study was conducted to investigate people’s forest dependency and contributions of forests to the livelihoods in the three hill districts of Chittagong Hill Tracts (CHT), Bangladesh. The study revealed that forest resources contribute significantly to rural community’s livelihoods and economic well-being. Using generalized logistic regressions, this study has also investigated the socioeconomic factors that affect people’s dependency on forest resources of CHT. The study revealed that people’s income from forest and forest-related occupation was positively aligned with their forest dependency. However, their education level significantly reduced their dependency on forest resources. Thus, educating the forest-dependent people and supporting alternative income generation activities should be appreciated for effective forest management in CHT. This study will be helpful to forest and environmental policy makers for CHT. 相似文献
17.
Airborne fungal spores are well known to cause respiratory allergic diseases particularly bronchial asthma, allergic rhinitis, rhino-conjunctivitis and allergic broncho-pulmonary aspergillosis in both adults and children. In order to monitor and analyze airborne fungal flora of the Karachi environment, an aeromycological study was conducted using a Burkard 7-Day Recording Volumetric Spore Trap from January to December 2010. The data recorded from the Spore Trap was further analyzed for percent catch determination, total spores concentration, seasonal periodicities and diurnal variations. Cladosporium spp (44.8%), Alternaria spp. (15.5%), Periconia spp (6.1%), Curvularia spp (2.1%), Stemphylium spp (1.3%) and Aspergillus/Penicillium type (1%) emerged to be major components constituting more than 70% of the airborne fungal flora. Cladosporium, Curvularia and Stemphylium displayed a clear seasonal trend, while there were no clear seasonal trends for other fungal spore types. Diurnal variations were observed to be mainly having daytime maxima. Spearman Rank Correlation Coefficient analysis was conducted using various weather parameters. The various fungal types showed a negative correlation with heat index, dew point, wind velocity and wind chill. However, a positive correlation was found with humidity, rain and barometric pressure. In fact, Alternaria, Bipolaris and Periconia showed a negative correlation with temperature, while Cladosporium and Periconia showed a negative correlation with heat index, dew point, wind velocity and wind chill. The barometric pressure was positively correlated with Cladosporium. On the basis of these findings, it can be concluded that a number of fungal spores are present in the atmosphere of Karachi throughout the year, with certain atmospheric conditions influencing the release, dispersion, and sedimentation processes of some genera. It is expected that clinicians will use the identified fungal flora for diagnosis and treatment and/or adopt preventative measures for allergic individuals. 相似文献
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Determining the depositional pattern by resistivity–seismic inversion for the aquifer system of Maira area,Pakistan 总被引:1,自引:0,他引:1
Velocity and density measured in a well are crucial for synthetic seismic generation which is, in turn, a key to interpreting
real seismic amplitude in terms of lithology, porosity and fluid content. Investigations made in the water wells usually consist
of spontaneous potential, resistivity long and short normal, point resistivity and gamma ray logs. The sonic logs are not
available because these are usually run in the wells drilled for hydrocarbons. To generate the synthetic seismograms, sonic
and density logs are required, which are useful to precisely mark the lithology contacts and formation tops. An attempt has
been made to interpret the subsurface soil of the aquifer system by means of resistivity to seismic inversion. For this purpose,
resistivity logs and surface resistivity sounding were used and the resistivity logs were converted to sonic logs whereas
surface resistivity sounding data transformed into seismic curves. The converted sonic logs and the surface seismic curves
were then used to generate synthetic seismograms. With the utilization of these synthetic seismograms, pseudo-seismic sections
have been developed. Subsurface lithologies encountered in wells exhibit different velocities and densities. The reflection
patterns were marked by using amplitude standout, character and coherence. These pseudo-seismic sections were later tied to
well synthetics and lithologs. In this way, a lithology section was created for the alluvial fill. The cross-section suggested
that the eastern portion of the studied area mainly consisted of sandy fill and the western portion constituted clayey part.
This can be attributed to the depositional environment by the Indus and the Kabul Rivers. 相似文献
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Shah MH Iqbal J Shaheen N Khan N Choudhary MA Akhter G 《Environmental monitoring and assessment》2012,184(3):1243-1252
Selected trace metals were estimated by atomic absorption spectrometry in the water and soil samples collected from the remote
region of Himalaya. The soil samples were analysed for soluble and acid extractable fraction of trace metals. In water samples,
Ca, Na, Mg and K emerged as dominant contributors, whereas, Ca, Na, K, Mg, Fe and Pb were estimated at comparatively higher
levels in the water extract of the soil. In case of acid extract of the soil samples, Ca, K, Fe, Mg, Mn and Na were found
at elevated concentrations. Based on mean levels of the metals, following decreasing concentration order was observed in water
samples: Ca > Na > Mg > K > Pb > Co > Cu > Zn > Mn > Cr > Fe > Cd > Li, however, in the acid extract of the soil, following
order was noted: Ca > K > Fe > Mg > Mn > Na > Pb > Zn > Cr > Li > Cu > Co > Cd. The correlation study revealed appreciably
diverse mutual relationships of trace metals in the water and soil samples. The multivariate cluster analyses exhibited divergent
apportionment of trace metals in water and soil samples. Among the trace metals, Cd, Pb, Li, Zn, Cr, Cu, Mn and Co exhibited
extreme to significant anthropogenic enrichment in the soil samples, while the rest of the metals were mostly contributed
by the natural processes. 相似文献
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Zulfiqar Ahmad Gulraiz Akhter Arshad Ashraf Alan Fryar 《Environmental monitoring and assessment》2010,170(1-4):395-406
A three-dimensional contaminant transport model has been developed to simulate and monitor the migration of disposal of hydrocarbon exploration produced water in Injection well at 2,100 m depth in the Upper Cretaceous Pab sandstone, Bhit area in Dadu district of Southern Pakistan. The regional stratigraphic and structural geological framework of the area, landform characteristics, meteorological parameters, and hydrogeological milieu have been used in the model to generate the initial simulation of steady-state flow condition in the underlying aquifer’s layers. The geometry of the shallow and deep-seated characteristics of the geological formations was obtained from the drilling data, electrical resistivity sounding surveys, and geophysical well-logging information. The modeling process comprised of steady-state simulation and transient simulation of the prolific groundwater system of contamination transport after 1, 10, 30 years of injection. The contaminant transport was evaluated from the bottom of the injection well, and its short- and long-term effects were determined on aquifer system lying in varying hydrogeological and geological conditions. 相似文献