Generalized cosmic Chaplygin gas inspired intermediate standard scalar field inflation     

Abdul Jawad  Shamaila Rani  Sidra Mohsaneen 《Astrophysics and Space Science》2016,361(8):268

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Tracing subsurface migration of contaminants from an abandoned municipal landfill   总被引：1，自引：1，他引：0  

E. A. Rahim Bahaa-eldin  I. Yusoff  S. Abdul Rahim  W. Y. Wan Zuhairi  M. R. Abdul Ghani 《Environmental Earth Sciences》2011,63(5):1043-1055

This paper aims at determining of inorganic leachate contamination for a capped unsanitary landfill in the absence of hydrogeological data. The 2D geoelectrical resistivity imaging, soil physicochemical characterization, and surface water analysis were used to determine contamination load and extent of selective heavy metal contamination underneath the landfill. The positions of the contaminated subsoil and groundwater were successfully delineated in terms of low resistivity leachate plumes of <10 Ωm. Leachate migration towards the reach of Kelang River could be clearly identified from the resistivity results and elevated concentrations of Fe in the river downslope toe of the site. Concentration of Fe, Mn, Ca, Na, K, Mg, Cu, Cr, Co, Ni, Zn, and Pb was measured for the subsoil samples collected at the downslope (BKD), upslope (BKU), and the soil-waste interface (BKI), of the landfill. The concentration levels obtained for most of the analyzed heavy metals significantly exceed the normal range in typical municipal solid waste landfill sites. The measured heavy metal contamination load in the subsoil is in the following order Fe ? Mn > Zn > Pb > Cr > Cu. Taking into consideration poor physical and chemical characteristics of the local soil, these metals first seem to be attenuated naturally at near surface then remobilize unavoidably due to the soil acidic environment (pH 4.2-6.18) which in turn, may allow an easy washing of these metals in contact with the shallow groundwater table during the periodic fluctuation of the Kelang River. These heavy metals are believed to have originated from hazardous industrial waste that might have been illegally dumped at the site.  相似文献   

Study of regional monsoonal effects on landslide hazard zonation in Cameron Highlands, Malaysia   总被引：1，自引：1，他引：0  

Abd Nasir Matori  Abdul Basith  Indra Sati Hamonangan Harahap 《Arabian Journal of Geosciences》2011,5(5):1069-1084

In general, landslides in Malaysia mostly occurred during northeast and southwest periods, two monsoonal systems that bring heavy rain. As the consequence, most landslide occurrences were induced by rainfall. This paper reports the effect of monsoonal-related geospatial data in landslide hazard modeling in Cameron Highlands, Malaysia, using Geographic Information System (GIS). Land surface temperature (LST) data was selected as the monsoonal rainfall footprints on the land surface. Four LST maps were derived from Landsat 7 thermal band acquired at peaks of dry and rainy seasons in 2001. The landslide factors chosen from topography map were slope, slope aspect, curvature, elevation, land use, proximity to road, and river/lake; while from geology map were lithology and proximity to lineament. Landslide characteristics were extracted by crossing between the landslide sites of Cameron Highlands and landslide factors. Using which, the weighting system was derived. Each landslide factors were divided into five subcategories. The highest weight values were assigned to those having the highest number of landslide occurrences. Weighted overlay was used as GIS operator to generate landslide hazard maps. GIS analysis was performed in two modes: (1) static mode, using all factors except LST data; (2) dynamic mode, using all factors including multi-temporal LST data. The effect of addition of LST maps was evaluated. The final landslide hazard maps were divided into five categories: very high risk, high risk, moderate, low risk, and very low risk. From verification process using landslide map, the landslide model can predict back about 13–16% very high risk sites and 70–93% of very high risk and high risk combined together. It was observed however that inclusion of LST maps does not necessarily increase the accuracy of the landslide model to predict landslide sites.  相似文献   

Seasonal Changes in Mayfly Communities and Abundance in Relation to Water Physicochemistry in Two Rivers at Different Elevations in Northern Peninsular Malaysia     

Suhaila Abdul Hamid  Mohd Ravi Che Salmah  Hamady Dieng  Abu Hassan Ahmad  Tomomitsu Satho  Fumio Miake 《湿地科学》2011,9(3):240-250

A field study was performed at rivers in Gunung Jerai forest reserve(Kedah,Malaysia) to assess seasonal changes in mayfly community structure and abundance in relation to altitude and water physicochemistry.Rivers at lower(Batu Hampar River) and higher(Teroi River) elevations were visited through dry and wet seasons in September 2007 to August 2008.Monthly visits were made to 20 sites on each river,and water and aquatic insects were sampled using D-pond aquatic nets.Water was warmer,more acid,and more turbid in Teroi River during wet season.Ammonia was the only nutrient exhibiting significant seasonal variations(greater during wet season).Chemical oxygen demand content was higher in Teroi River where biochemical oxygen demand content was low during wet season.Species richness was higher in Batu Hampar River,but displayed seasonal variations only in Teroi River.Among the eight families encountered,Baetidae was the commonest.Baetid abundance was usually high during wet season,and those belonging to the dominant genus(Baetis) were more abundant in Teroi River.Heptageniidae was the second commonest family;its predominant genus,Thalerospyrus was more abundant in Teroi River during dry season.Caenidae,Leptophlebiidae and Oligoneuriidae were only found in Batu Hampar River where their abundances peaked during dry season,i.e.,Habrophlebiodes sp.and Isonychia sp.Ephemerellidae and Teloganodidae occurred only in Teroi River,with the first found only during dry season.Mayflies were recorded under very distinct physicochemical conditions,illustrating their potential usefulness for assessing water quality.Caenids,leptophlebids,oligoneurids ephemerellids and teloganodids seem to be particularly sensitive to temperature,acidity,turbidity,chemical oxygen demand and biochemical oxygen demand,parameters that varied with river altitude.  相似文献   

CFD simulation and experimental analysis of flow dynamics and grinding performance of opposed fluidized bed air jet mill     

M. Sri Raj Rajeswari  K.A.M. Azizli  S.F.S. Hashim  M.K. Abdullah  M. Abdul Mujeebu  M.Z. Abdullah 《International Journal of Mineral Processing》2011,98(1-2):94-105

This paper presents a three dimensional Computational Fluid Dynamics (CFD) model to investigate the flow dynamics of solid–gas phases during fine grinding in an air jet mill. Alpine 100AFG fluidized bed air jet mill is considered for the study and the jet milling model is simulated using FLUENT 6.3.2 using a standard k-ε model. The model is developed in GAMBIT 2.3.16 and meshed by tet/hybrid (T-Grid) and Triangular (Pave) meshes. The effects of operating parameters such as solid feed rate, grinding air pressure and internal classifier speed on the performance of the jet mill are analyzed. The CFD simulation results are presented in the forms of dual phase vector plot, volume fraction of phases and particle trajectories during fine grinding process. The mass of ground feed entering and leaving the cyclone (underflow) is also computed by simulation. The proposed model gives realistic predictions of the flow dynamics within the jet mill. Experiments are conducted on the Alpine 100AFG jet mill to study the particle size, morphology and mass of the ground product. The numerical results are found in good agreement with the experimental results.  相似文献   

Evaluation of the fishery status for King Soldier Bream Argyrops spinifer in Pakistan using the software CEDA and ASPIC     

刘群 《中国海洋湖沼学报》2015,33(4):966-973

Catch and effort data were analyzed to estimate the maximum sustainable yield(MSY) of King Soldier Bream, Argyrops spinifer(Forssk?l, 1775, Family: Sparidae), and to evaluate the present status of the fish stocks exploited in Pakistani waters. The catch and effort data for the 25-years period 1985–2009 were analyzed using two computer software packages, CEDA(catch and effort data analysis) and ASPIC(a surplus production model incorporating covariates). The maximum catch of 3 458 t was observed in 1988 and the minimum catch of 1 324 t in 2005, while the average annual catch of A. spinifer over the 25 years was 2 500 t. The surplus production models of Fox, Schaefer, and Pella Tomlinson under three error assumptions of normal, log-normal and gamma are in the CEDA package and the two surplus models of Fox and logistic are in the ASPIC package. In CEDA, the MSY was estimated by applying the initial proportion(IP) of 0.8, because the starting catch was approximately 80% of the maximum catch. Except for gamma, because gamma showed maximization failures, the estimated results of MSY using CEDA with the Fox surplus production model and two error assumptions, were 1 692.08 t(R 2 =0.572) and 1 694.09 t( R 2 =0.606), respectively, and from the Schaefer and the Pella Tomlinson models with two error assumptions were 2 390.95 t( R 2 =0.563), and 2 380.06 t( R 2 =0.605), respectively. The MSY estimated by the Fox model was conservatively compared to the Schaefer and Pella Tomlinson models. The MSY values from Schaefer and Pella Tomlinson models were the same. The computed values of MSY using the ASPIC computer software program with the two surplus production models of Fox and logistic were 1 498 t(R 2 =0.917), and 2 488 t( R 2 =0.897) respectively. The estimated values of MSY using CEDA were about 1 700–2 400 t and the values from ASPIC were 1 500–2 500 t. The estimates output by the CEDA and the ASPIC packages indicate that the stock is overfished, and needs some effective management to reduce the fishing effort of the species in Pakistani waters.  相似文献   

New holographic dark energy in modified f(R) Horava-Lifshitz gravity     

Abdul Jawad  Surajit Chattopadhyay 《Astrophysics and Space Science》2014,353(1):293-299

In this paper, we study the new holographic dark energy model in the framework of modified f(R) Horava-Lifshitz Gravity. We apply correspondence scheme to construct model the in underlying scenario using power-law form of scale factor. To explore accelerated expansion of the universe, some well-known cosmological parameters (equation of state parameter and squared speed of sound) and cosmological planes (ω _Λ – \(\omega'_{\varLambda}\) and statefinder) are discussed for reconstructed model. It is interesting to conclude that these parameters represent phantom behavior of the universe with stable configuration. also, the cosmological planes show compatible results with recent observations for accelerated expansion of the universe.  相似文献   

Trace gases and PM2.5-bound metal abundance over a tropical urban environment,South India     

M  Abdul Shukkur  V.G  Gopikrishna  N.G  Vishnu  Mohan  Mahesh 《Journal of Atmospheric Chemistry》2021,78(3):193-208

Pre and Post-Monsoon levels of ambient SO₂, NO₂, PM_2.5 and the trace metals Fe, Cu, etc. were measured at industrial and residential regions of the Kochi urban area in South India for a period of two years. The mean PM_2.5, SO₂ and NO₂ concentrations across all sites were 38.98?±?1.38 µg/m³, 2.78?±?0.85 µg/m³ and 11.90?±?4.68 µg/m³ respectively, which is lower than many other Indian cities. There was little difference in any on the measured species between the seasons. A few sites exceeded the NAAQS (define acronym and state standard) and most of the sites exceeded WHO (define acronym and state standard) standard for PM_2.5. The average trace metal concentrations (ng/m³) were found to be Fe (32.58)?>?Zn (31.93)?>?Ni (10.13)?>?Cr (5.48)?>?Pb (5.37)?>?Cu (3.24). The maximum concentration of trace metals except Pb were reported in industrial areas. The enrichment factor, of metals relative to crustal material, indicated anthropogenic dominance over natural sources for the trace metal concentration in Kochi’s atmosphere. This work demonstrates the importance of air quality monitoring in this area.

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National ocean policy—new opportunities for Malaysian ocean development     

Abdul Hamid Saharuddin   《Marine Policy》2001,25(6)

Being a littoral state, Malaysian maritime sectors provide the basis for the growth and development of marine-related activities. As the country enters the new millennium along with the ‘2020 Vision’ which serves as the basic template against which the economic performance of these sectors should be judged, it poses a new challenge for Malaysia in developing these sectors. This paper attempts to address three basic issues: Firstly, is there any national ocean policy in place? Secondly, are the maritime sectors adequately organized to play an important role in achieving the objectives? Thirdly, what are the opportunities available in developing the ocean?It can be seen that existing policies to develop comprehensive ocean governance have not received the full attention they deserve. Organizational structures governing the ocean for implementing national policies are well in place but in a fragmented and uncoordinated fashion. As a result, sectoral and intersectoral management problems were created such as multiple-use conflicts, overlapping of jurisdiction and duplication of efforts. Environmental problems have also not been properly addressed. A few sectors have been identified as offering opportunities to further develop the Malaysian maritime areas. Among these are marine education and human resources development, marine tourism and the seafood industry.  相似文献   

Integrated geoelectrical resistivity and hydrogeochemical methods for delineating and mapping heavy metal zone in aquifer system   总被引：1，自引：0，他引：1  

Nur Islami  Samsudin Hj Taib  Ismail Yusoff  Azman Abdul Ghani 《Environmental Earth Sciences》2018,77(10):383

A novel study on using geoelectrical resistivity, soil property, and hydrogeochemical analysis methods for delineating and mapping of heavy metal in aquifer system is presented in this paper. A total of 47 surveys of geoelectrical resistivity with Wenner configuration were conducted to determine the subsurface and the groundwater characteristics. The groundwater sample from 53 existing wells and 2 new wells has been analyzed to derive their water chemical content. The chemical analysis was done on the soil sample obtained from new two wells and from selected locations. The water and soil chemical analysis results from the new two wells were used as calibration in resistivity interpretation. The occurrence of heavy metal in aquifer system was expected to detect using the geoelectrical resistivity survey for the whole study area. The result of groundwater analysis shows that the groundwater sample contains a relatively low concentration of Fe (<?0.3 mg/L) elongating from the south up to the middle region. While in the middle and the northwestern, Fe concentration is relatively high (around 12 mg/L). Chemical analysis of soil sample shows that in the lower resistivity zone (<?18 Ωm), Al and Fe concentrations are comparatively high with an average of 68,000 and 40,000 mg/kg, respectively. Starting from the middle to the northwestern zone, the resistivity value appears to be low. It is definitely caused by higher Al and Fe concentration within the soil, and it is supported also by lower total anion content in the groundwater. While the resistivity value of more than 40 Ωm in aquifers is obtained in the zone which Fe concentration is relatively lower in the soil but not present in the groundwater. Correlation Fe concentration in the soil and Fe concentration in the groundwater sample shows the trend of positively linear; however, the Al concentration in soil has no correlation with Al content in groundwater. Finally, the probability of high heavy metal zone in the aquifer system is easily delineated by the distribution of geoelectrical resistivity presented in depth slice shapes which extend from the Boundary Range Composite Batholith in the north to the northwest.  相似文献