Influence of saturation on rainfall generated landslides in shale along Murree-Kohala road,Pakistan

On August 10, 2010 a series of landslides of more than 90,000 m³ occurred along the Muree-Kohala road in the northern area of Pakistan. A study was undertaken to evaluate the likely impacts of percent saturation and bulk density on mobilized shear strength along the basal rupture surface of the landslide. A series of unconfined compression test and unconsolidated undrained triaxial tests were performed on remolded samples of different densities with varied percentages of saturation. The results of these tests suggest that soil cohesion and friction decreases with increasing saturation. The tests also showed that the shear strength parameters tend to increase with increasing dry density; however, all the samples exhibited a noticeable loss of shear strength with increasing degree of saturation, independent of soil density.Limit equilibrium slope stability analyses were performed along the most probable failure planes, based on shear strength parameters corresponding to degrees of saturation, which varied between 30% to about 100%. This resulted in drop of factor of safety from FS = 1.64 down to 0.51 as the degree of saturation approaches unity.These results suggest that the causative factor in triggering the landslide along Murree-Kohala was the partial saturation of the zone that developed the basal rupture plane. As rain infiltrated the slope, the bulk unit weight of the soil increased, while the shear strength along the developing plane of rupture decreased sufficiently to concentrate shear strain when the material became more than 60% saturation (FS < 1.0).     

Spatio‐temporal distribution of actual evapotranspiration in the Indus Basin Irrigation System

Strategic planning of optimal water use requires an accurate assessment of actual evapotranspiration (ET_a) to understand the environmental and hydrological processes of the world's largest contiguous irrigation networks, including the Indus Basin Irrigation System (IBIS) in Pakistan. The Surface Energy Balance System (SEBS) has been used successfully for accurate estimations of ET_a in different river basins throughout the world. In this study, we examined the application of SEBS using publically available remote sensing data to assess spatial variations in water consumption and to map water stress from daily to annual scales in the IBIS. Ground‐based ET_a was calculated by the advection‐aridity method, from nine meteorological sites, and used to evaluate the intra‐annual seasonality in the hydrological year 2009–2010. In comparison with the advection‐aridity, SEBS computed daily ET_a was slightly underestimated with a bias of ?0.15 mm day^?1 during the kharif (wet; April–September) season, and it was overestimated with a bias of 0.23 mm day^?1 in the rabi (dry; October–March) season. Monthly values of the ET_a estimated by SEBS were significantly (P < 0.05) controlled by mean air temperature and rainfall, among other climatological variables (relative humidity, sunshine hours and wind speed). Because of the seasonal (kharif and rabi) differences in the water and energy budget in the huge canal command areas of the IBIS, ET_a and rainfall were positively correlated in the kharif season and were negatively correlated during the rabi season. In addition, analysis of the evaporation process showed that mixed‐cropping and rice–wheat dominated areas had lower and higher water consumption rates, respectively, in comparison with other cropping systems in the basin. Basin areas under water stress were identified by means of spatial variations in the relative evapotranspiration, which had an average value of 0.59 and 0.42 during the kharif and the rabi seasons, respectively. The hydrological parameters used in this study provide useful information for understanding hydrological processes at different spatial and temporal scales. Results of this study further suggest that the SEBS is useful for evaluation of water resources in semi‐arid to arid regions over longer periods, if the data inputs are carefully handled. Copyright © 2014 John Wiley & Sons, Ltd.     

Treatment of vegetable oil mill effluent using crab shell chitosan as adsorbent

In this study, a naturally available crab shell chitosan of low molecular weight (20?kDa) has been used as adsorbent to evaluate the pollution load in vegetable oil mill effluent. A series of batch experiment was conducted by varying chitosan dosage (100?C400?mg), pH (2?C9), stirring time (15?C90)?min and agitation speed (25?C150?rpm) to study their effects on adsorption and flocculation processes. The parameters considered for adsorption study are chemical oxygen demand, total suspended solids, electrical conductivity and turbidity. The maximum reduction in chemical oxygen demand, total suspended solids, electrical conductivity and turbidity is 74, 70, 56 and 92?% , respectively. The observed experimental result showed that crab shell chitosan could able to reduce significantly the chemical oxygen demand, turbidity, electrical conductivity and suspended matter. The optimum conditions were estimated as 400?mg/l chitosan, pH 4 and 45?min of mixing time with mixing speed of 50?rpm. Chitosan showed very good pollution removal efficiency and can be used for the effective treatment of vegetable oil mill effluent.     

Instabilities in a nonstationary model of self-gravitating disks. III. The phenomenon of lopsidedness and a comparison of perturbation modes

This is an examination of the gravitational instability of the major large-scale perturbation modes for a fixed value of the azimuthal wave number m = 1 in nonlinearly nonstationary disk models with isotropic and anisotropic velocity diagrams for the purpose of explaining the displacement of the nucleus away from the geometric center (lopsidedness) in spiral galaxies. Nonstationary analogs of the dispersion relations for these perturbation modes are obtained. Critical diagrams of the initial virial ratio are constructed from the rotation parameters for the models in each case. A comparative analysis is made of the instability growth rates for the major horizontal perturbation modes in terms of two models, and it is found that, on the average, the instability growth rate for the m = 1 mode with a radial wave number N = 3 almost always has a clear advantage relative to the other modes. An analysis of these results shows that if the initial total kinetic energy in an isotropic model is no more than 12.4% of the initial potential energy, then, regardless of the value of the rotation parameter Ω, an instability of the radial motions always occurs and causes the nucleus to shift away from the geometrical center. This instability is aperiodic when Ω = 0 and is oscillatory when Ω ≠ 0 . For the anisotropic model, this kind of structure involving the nucleus develops when the initial total kinetic energy in the model is no more than 30.6% of the initial potential energy.     

Mesoscale and Nutrient Conditions Associated with the Massive 2008 Cochlodinium polykrikoides Bloom in the Sea of Oman/Arabian Gulf

Cochlodinium polykrikoides formed large blooms in the coastal waters of Oman from October 2008 through mid-January 2009, and satellite images from Aqua-MODIS and region-wide reports suggest that this bloom was found throughout the Arabian Gulf and Sea of Oman for more than 10 months. The unusual occurrence of this species appears to have supplanted the more regularly occurring bloom species, Noctiluca scintillans, in 2008–2009. For the first 2 weeks of the coastal Omani bloom, C. polykrikoides abundance was near monospecific proportions, with cell densities ranging from 4.6?×?10³ to 9?×?10⁶ cells L^?1 and very high levels of chlorophyll a (78.0 μg L^?1) were also recorded. The regional progression of the bloom likely began with stronger than normal upwelling along the Iranian and northern Omani coasts during the southwest monsoon in late summer, followed by discharge of unusually warm coastal plume water along the coast of Oman with the reversal of monsoonal winds in late October. The occurrence and persistence of high densities of C. polykrikoides in Oman coastal water were also significantly influenced by an elevated nutrient load and warmer than normal temperatures. Concentrations of nutrients, especially NH₄ ⁺, urea, PO₄ ^3?, and organic nitrogen and phosphorus, were manyfold higher than observed in the year prior or since. These findings suggest that mesoscale features were important in bloom dynamics more regionally, but locally the bloom was sustained by nutrient enrichment supplemented by its mixotrophic capabilities.     

Characteristics of lipid tracer compounds transported to the Arabian Gulf by runoff from rivers and atmospheric dust transport

River runoff and atmospheric fallout (dust and air particulate matter) are major input sources of natural and anthropogenic terrestrial organic and inorganic components to the Arabian seas. In this study, we report on the various lipid tracer compounds that might be transported to the Arabian Gulf by rivers, dust, and air particulate matter. These are based on geochemical analysis of sediment, dust, and particulate samples collected from Iraq, Kuwait, and Saudi Arabia. The samples were extracted with a dichloromethane/methanol mixture and analyzed by gas chromatography-mass spectrometry. The extractable organic compounds (lipids) in the samples include n-alkanes, n-alkanoic acids, n-alkanols, methyl n-alkanoates, steroids, triterpenoids, carbohydrates, and petroleum hydrocarbons. The steroids and triterpenoids were major components in river and wetland samples. The major sources of these lipids were from natural vegetation, microbial (plankton and bacteria) residues in the sediments, sand, and soils, with some contribution from anthropogenic sources. Accordingly, these sources could be major inputs to the Arabian seas besides the autochthonous marine products. Future studies of the organic and inorganic biogeochemistry on river, dust, and coastal areas are needed to characterize the various regional sources, transformation, and diagenetic processes of the organic matter en route to the marine environment.     

Groundwater budget for the upper and middle parts of the River Gash Basin, eastern Sudan

The River Gash Basin is filled by the Quaternary alluvial deposits, unconformably overlying the basement rocks. The alluvial deposits are composed mainly of unconsolidated layers of gravel, sand, silt, and clays. The aquifer is unconfined and is laterally bounded by the impermeable Neogene clays. The methods used in this study include the carry out of pumping tests and the analysis of well inventory data in addition to the river discharge rates and other meteorological data. The average annual discharge of the River Gash is estimated to be 1,056?×?10⁶ m³ at El Gera gage station (upstream) and 587?×?10⁶ m³ at Salam-Alikum gage station (downstream). The annual loss mounts up to 40% of the total discharge. The water loss is attributed to infiltration and evapotranspiration. The present study proofs that the hydraulic conductivity ranges from 36 to 105 m/day, whereas the transmissivity ranges from 328 to 1,677 m²/day. The monitoring of groundwater level measurements indicates that the water table rises during the rainy season by 9 m in the upstream and 6 m in the midstream areas. The storage capacity of the upper and middle parts of the River Gash Basin is calculated as 502?×?10⁶ m³. The groundwater input reach 386.11?×?10⁶ m³/year, while the groundwater output is calculated as 365.98?×?10⁶ m³/year. The estimated difference between the input and output water quantities in the upper and middle parts of the River Gash Basin demonstrates a positive groundwater budget by about 20?×?10⁶ m³/year     

Embryonic development of Pelteobagrus fulvidraco （Richardson, 1846）

1 INTRODUCTION Pelteobagrus fulvidraco (Richardson, 1846) or yellow catfish is slender and scaleless with a gently sloping dorsal profile from anterior to posterior. It is generally black-brown to black-yellow on the back, light yellow on the belly, with …     

Effects of Replacing Fishmeal with Animal By-products Meal Supplementation in Diets on the Growth and Nutrient Utilization of Mangrove Red Snapper

A feeding trial was conducted for 75 d to evaluate the nutritive value of a mixture of animal by-products(MAB) as a possible protein source in diets for juvenile mangrove red snapper,Lutjanus argentimaculatus(mean initial body weight,30 g). Fish were fed one of five isonitrogenous diets(40% crude protein) replacing 0,25%(MAB25),50%(MAB50),75%(MAB75) and 100%(MAB100) of fish meal protein with similar percentages of MAB. The MAB consisted of 25% cow liver meal,20% leather meal,20% meat and bone meal,15% blood meal,10% APC(poultry feather meal),8% poultry manure dried,1.5% choline and 0.5% chromic oxide. After 75 d of feeding,fish fed with diets MAB50,MAB75 and MAB100 exhibited significantly lower growth per-formance than that of fish fed with control and MAB25 diets. The optimum level of MAB was estimated to be 23%. Replacement of fish meal by MAB23% showed the following performance:maximum weight gain,510%;SGR,2.39% and FCE,2.83%. The MAB substitution up to 75% of fish meal protein in diets did not show differences in apparent protein digestibility(83.6% for MAB25,79.2% for MAB50,78.7% for MAB75) compared with control(83.4%),whereas in MAB100 group digestibility(65.3%) was sig-nificantly lower than in other groups. The apparent phosphorus absorption of test diet groups was significantly higher(37.1% for MAB25,28.5% for MAB50,55.6% for MAB75 and 54.5% for MAB100) than that of control(11.2%). The levels of protein and ash in the whole body,carcass and viscera increased as MAB substitution in diets increased,whereas lipids and moisture remained con-sistent among all treatment groups. These results showed that approximately 23% of fish meal protein could be replaced by a mixture of animal by-products for juvenile snapper growing from 30 g to 167 g in 75 d without compromising growth performance and feed efficiency.