Probabilistic analyses of soil consolidation by prefabricated vertical drains for single‐drain and multi‐drain systems

Natural soils are one of the most inherently variables in the ground. Although the significance of inherent soil variability in relation to reliable predictions of consolidation rates of soil deposits has long been realized, there have been few studies that addressed the issue of soil variability for the problem of ground improvement by prefabricated vertical drains. Despite showing valuable insights into the impact of soil spatial variability on soil consolidation by prefabricated vertical drains, available stochastic works on this subject are based on a single‐drain (or unit cell) analyses. However, how the idealized unit cell solution can be a supplement to the complex multi‐drain systems for spatially variable soils has never been addressed in the literature. In this study, a rigorous stochastic finite elements modeling approach that allows the true nature of soil spatial variability to be considered in a reliable and quantifiable manner, both for the single‐drain and multi‐drain systems, is presented. The feasibility of performing an analysis based on the unit cell concept as compared with the multi‐drain analysis is assessed in a probabilistic context. It is shown that with proper input statistics representative of a particular domain of interest, both the single‐drain and multi‐drain analyses yield almost identical results. Copyright © 2016 John Wiley & Sons, Ltd.     

Stormflow generation involving pipe flow in a zero‐order basin of Peninsular Malaysia

Hydrological responses in a zero‐order basin (ZOB), a portion of whose discharge emerged via preferential flow through soil pipes, were examined over a 2‐year period in Peninsular Malaysia to elucidate primary stormflow generation processes. Silicon (Si) and specific conductance (EC) in various runoff components were also measured to identify their sources. ZOB flow response was dependent on antecedent precipitation amount; runoff increased linearly with precipitation during events >20 mm in relatively wet antecedent moisture conditions. Runoff derived from direct precipitation falling onto saturated areas accounted for <0·2% of total ZOB flow volume during the study period, indicating the predominance of subsurface pathways in ZOB flow. ZOB flow (high EC and low Si) was distinct from perennial baseflow via bedrock seepage (low EC and high Si) 5 m downstream of the ZOB outlet. Pipe flow responded quickly to ZOB flow rate and was characterized by a threshold flow capacity unique to each pipe. Piezometric data and pipe flow records demonstrated that pipes located deeper in the soil initiated first, followed by those at shallower depths; initiation of pipe flow corresponded to shallow groundwater rise above the saprolite‐soil interface. Chemical signatures of pipe flow were similar to each other and to the ZOB flow, suggesting that the sources were well‐mixed soil‐derived shallow groundwater. Based upon the volume of pipe flow during storms, the combined contribution of the pipes monitored accounted for 48% of total ZOB flow during the study period. Our results suggest that shallow groundwater, possibly facilitated by preferential flow accreted above the saprolite–soil interface, provides dominant stormflow, and that soil pipes play an important role in the rapid delivery of solute‐rich water to the stream system. Copyright © 2006 John Wiley & Sons, Ltd.     

Sedimentary facies of Maastrichtian to Danian deposits in Amur River area, Russian Far East

Sedimentary facies of the Tsagayan Formation is distributed in the eastern Zeya-Bureya Basin has been analyzed. The formation is of the Maastrichtian to Danian in age and characterized by the cyclicity of the fining-upwards successions. Analysis of environmental changes during the K/T boundary is the focus of this study. Five facies have been identified: Facies A, thick and laterally extensive coarse-grained to medium-grained sandstone units, interpreted as channelfill deposits; Facies B, parallel-laminated to massive mudstone units interpreted as interchannel lakes and flood plain deposits; Facies C, sheet-like medium-grained to fine-grained sandstones interpreted as crevasse splay deposits;Facies D, coal to coaly mudstone beds interpreted as deposits ofpeatlands; Facies E, very poorly sorted sandy mudstone beds interpreted as debris flow deposits. Fluvial environments with the low-relief flat topography was inferred. A channel transported large volumes of clasts, and a flood basin with interchannel lakes and peatlands was deciphered. Any distinct change of sedimentary environments has not been identified throughout the Tsagayan Formation (including the K/T boundary). However, two beds of debris flow deposits were identified. The one occurs at the uppermost part of the lower Tsagayan Subformation and contains dinosaur fossils. The other is intercalated in the upper Tsagayan Subformation.     

Analysis of generalized ghost version of pilgrim dark energy

The proposal of pilgrim dark energy is based on the speculation that phantom-like dark energy possesses enough resistive force to preclude the black hole formation in the later universe. We explore this phenomenon by assuming the generalized ghost version of pilgrim dark energy. We find that most of the values of the interacting (ξ ²) as well as pilgrim dark energy (u) parameters push the equation of state parameter towards phantom region. The squared speed of sound shows that this model remains stable in most of the cases of ξ ² and u. We also develop $\omega_{\varLambda}\mbox{--}\omega'_{\varLambda}$ plane and observe that this model corresponds to thawing as well as freezing regions. Finally, it is shown that the non-interacting and interacting generalized ghost versions of pilgrim dark energy correspond to ΛCDM limit on the statefinder plane.     

Groundwater investigation in Kuala Selangor using vertical electrical sounding (VES) surveys

Integrated geoelectrical and hydrochemical surveys were used to investigate and delineate different types of groundwater in the Kuala Selangor alluvial aquifer. Previous hydrogeological borehole investigation showed that this aquifer contains several types of groundwater in relation to its salinity. The high salinity of the groundwater in some areas is believed to be due to either saltwater intrusion from the nearby sea or river infiltration during high tide season. The vertical electrical sounding (VES) method was employed to study and map the subsurface variation of resistivity in the area. For each sounding measurement, a total spread length of 300 m was obtained with a vertical depth penetration of about 60 to 75 m. Chemical analysis of the groundwater samples taken from both shallow and deep boreholes was carried out for the water quality determination. A total of 45 VES stations were succesfully established along three parallel roads with a direction almost perpendicular to the coastal line. The distance between stations varies from 1 to 2 km with a maximum length of about 60 km surveyed line. Results of the vertical electrical soundings as well as the hydrochemistry of the groundwater samples show that the soil and groundwater in the study area can be grouped into fresh and brackish water zones. The subsurface resisitivity sections derived from the VES study suggest that the area is dominated by brackish soil and groundwater zones, especially in the area towards the coast. This result appears to agree well with the groundwater pumped from boreholes scattered around in the area. Water drawn from boreholes near the coast showed higher salinity compared to the water pumped from inland boreholes. Chloride values greater than 250 mg/L are considered to represent the brackish zones whilst values less than 250 mg/L represents zones of fresh soil and groundwater.     

Particulate matter dispersion and haze occurrence potential studies at a local palm oil mill

The emissions from palm oil industry through incineration and open burning are the major sources of air pollutions contribution in Malaysia. The consequence of increasing the particulate concentration, the particulate matter dissolves with vapour and grows into droplets when the humidity exceeds approximately 70% and causing opaque situation known as haze. This work focuses on the dispersion particulate matter from palm oil mill. Gaussian Plume Model from a point source, subject to various atmospheric conditions is used to calculate particulate matter concentration then display the distribution of plume dispersion using geographic information system. Atmospheric Stability, mixing height, wind direction, wind speed, natural and artificial features play an important role in dispersion process. Study on the dispersion of particulate matters and the haze potential are presented as a case study in this paper. The data obtained will be served as the purpose of modeling the transport of particulate matter for obtaining permits and prevention of significant deterioration to the environment.     

Water and sediment quality, partial mass budget and effluent N loading in coastal brackishwater shrimp farms in Bangladesh

The present study aimed to quantify the water and sediment quality and growth and production parameters and to establish nutrient budgets for an average of five selected semi-intensive shrimp ponds in Bangladesh over a growing cycle. Physico-chemical parameters of water and sediments were measured and analyzed by standard methods. Gross yield (kg ha-1) of shrimp was calculated from the stocking and harvesting data. Finally, a partial nutrient mass budget for N and P was calculated. Most of the parameters of water and sediments correlated significantly with each other suggesting a high degree of interactions between different parameters in the system. Significantly higher concentrations of all species of nitrogenous nutrients were recorded in the effluent waters than that entering into the ponds. Therefore, a high loading and net output of nitrogenous nutrients in effluent waters was documented. The study also indicated a net discharge of solids and minerals through effluent loading. However, significantly lower concentrations of phosphorus in the effluent water indicated a net retention and trapping of phosphatic nutrients in the environment. Total production ranged between 532.0 and 697.0 kg ha-1 cycle-1 and P. monodon production between 484.0 and 562.0 kg ha-1 cycle-1. Ponds gained nitrogen primarily from intake water (55%) and fertilizers (29%), and nitrogen was lost primarily from water exchange (78%) and harvested shrimp (12%). Phosphorus gain occurred mostly from intake water (52%) and fertilizers (25%), and phosphorus was lost primarily from water exchange (52%) and harvested shrimp (3.3%). About 10% of input nitrogen and 44% of phosphorus were not accounted for in measured losses, and presumably were fixed or metabolized in the system. On average, 78 g N was discharged to and 25 g P was removed from the surrounding water by the system for each kilogram of shrimp produced. Mean conversion of feed nitrogen and phosphorus to shrimp flesh averaged 74% and 40%, respectively. It was concluded that semi-intensive systems serve as net supplier of N to and net remover of P from the surrounding water.     

结合遥感和气象数据的森林火险监测研究——以马来西亚半岛为例

结合遥感和气象数据,基于可燃物引燃能量的物理概念,利用火灾敏感性指数(FSI)进行森林火险监测和评估。计算FSI只需要两个参数,即可燃物的温度和湿度,两者均可以从遥感和气象数据获得。利用遥感数据进行可燃物类型制图,并根据可燃物易燃性对FSI的值进行调整计算。利用MODIS探测的火点数据对马来西亚半岛火灾前9天的FSI进行了比较分析,发现随着火灾发生日期的接近,FSI的值逐渐升高,这个趋势在火灾发生的前4天中表现的尤其明显。结果表明,FSI将遥感数据和气象数据两者紧密结合在一起,能够很好地对森林火险进行监测和预警,是一种性能优越的火险评价指数。FSI可用于计算可燃物的点燃概率以及在不同的生态系统中进行火险的比较,并且因其灵活性和可扩展性,有利于不同类型火险模型的集成和发展。     

Time-dependent plume front positioning and its dynamics coupled with seasonal river efflux

Ocean Dynamics - The time-dependent plume front positioning with respect to different tidal phases and its dynamics coupled with seasonal river efflux on the shelf off Kochi, southwest coast of...