Friday 28 December 2018

Monday 24 December 2018

A Mechanics-Based Procedure for Predicting Groundwater-Rise-Induced Slope Displacements: (OAJESS)- Lupine Publishers


A procedure for predicting cumulative slope displacements induced by groundwater table changes is proposed. The proposed procedure incorporates a back-calculation technique for the soil strength parameter based on the records of slope displacement and ground water table changes. The analytical tool for the back-calculation is a limit-equilibrium-based finite displacement method (FFDM) requiring force and moment equilibrium, displacement compatibility, and a hyperbolic shear stress-displacement constitutive law. The analyzed potential sliding mass is a statically determinate system, providing a closed-form solution for the displacement of the slope. Two well documented case histories of periodic rainfall-induced slope displacements are used to validate the proposed analytical procedures. The hyperbolic soil strength parameters back-calculated from the first event of slope displacement can be used as operational soil strength parameters for predicting subsequent slope displacements caused by rainfall-induced groundwater table elevation changes. The proposed method alleviates possible difficulties associated with the evaluation of soil strength using undisturbed soil sampling of colluviums in foothill areas. The proposed method requires little computer time in deriving useful information of slope displacement which cannot be achieved using conventional limit equilibrium methods or advanced numerical analyses. The proposed analytical procedure is valid only for simulating instantaneous sliding where time-dependent viscous (or creep) deformation is not dominant.

https://lupinepublishers.com/environmental-soil-science-journal/fulltext/a-mechanics-based-procedure-for-predicting-groundwater-rise-induced-slope-displacements.ID.000117.php
https://lupinepublishers.com/environmental-soil-science-journal/abstracts/a-mechanics-based-procedure-for-predicting-groundwater-rise-induced-slope-displacements.ID.000117.php

Wednesday 5 December 2018

Evaluation of Host Associated Genetic Markers for Rapid PCR Based Identification of Fecal Contamination Sources in Water: (OAJESS)-Lupine Publishers


The water quality of many waterways in the state of Alabama, and in the nation as a whole, is deteriorating due to point and nonpoint source pollution from human and animal waste. Accurate identification of contamination sources is essential if we are to develop cost-effective pollution control strategies. The direct detection of host specific genetic markers by Polymerase Chain Reactions (PCR) has been widely used in identifying sources of fecal contamination in environmental waters. In this study, we conducted experiments to validate genetic markers associated with deer/elk, Canada goose, dog, and cattle for Microbial Source Tracking (MST) in Alabama. End point PCR was performed on 10 raw sewage samples and 133 fecal samples from nine animal species. Our results showed that CowM3, GFD (goose), and deer/elk associated markers have acceptable specificity and sensitivity, making them suitable for MST studies. However, the dog marker and one of the cattle markers (CowM2) exhibited cross reactions with other fecal samples. The performance of these host associated markers in environmental water was evaluated using both end point and quantitative PCR (qPCR). Human, goose, and dog markers were detected in several water samples by end point PCR; the human marker and CowM2 marker were also detected by qPCR. Samples collected after a significant rainfall event showed the highest frequency of genetic marker detection. Both human and Canada geese contributed to fecal pollution in samples from Parkerson Mill Creek.

http://www.lupinepublishers.com/environmental-soil-science-journal/abstracts/OAJESS.MS.ID.000107.php
http://www.lupinepublishers.com/environmental-soil-science-journal/pdf/OAJESS.MS.ID.000107.pdf


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