Quantification of effect of convergence in porous media flow

An attempt is made in this study to quantify the effect of convergence on macroscopic scale in the case of flow through porous media. Experiments are conducted separately on specially conceived parallel flow permeameter and converging flow permeameter keeping identical inlet and outlet conditions, using eight sizes of coarse granular media and water as the fluid medium. The media is sieved through sieves of different sizes to separate the crushed rock into sizes of 3.25 mm, 4.73 mm, 10.00 mm, 11.64 mm, 13.10 mm, 20.10 mm, 28.90 mm and 39.50 mm and glass spheres of 15.41 mm, 18.03 mm and 28.37 mm. As the effect of convergence is predominant in non- Darcian zones of flow, such as flow near the well, flow through rock fills, filters etc.,, the scope of the present work is restricted to flow regime with Re \u3e 10. (After Kovacs) Forchheimer’s equation ( i = aV + bV2 ) is applied to analyze the experimental data. Equations are derived for Darcy parameter (a) and Non-Darcy parameter (b) of the Forchheimer’s equation for the crushed rock and glass spheres by relating to size of the media (d) in both parallel flow condition and converging flow condition. From the results it is inferred that for a given rate of flow through a known size of aquifer having predetermined grain size, the resistance to flow is higher in the parallel flow compared to similar media conditions in converging flow configurations. A comparison is then made between the coefficients of the equation, computed for parallel and converging configurations of flow. The difference in these values is expressed in terms of a factor called ‘Integrated Convergence factor (Cfi)’. It is concluded that the convergence of stream lines of seepage flow has a clear and profound influence on the relationship between resistance and regime. In order to make the findings reliable and suitable to field applications, the derived expressions are subjected to corrections for porosity effect, wall effect and tortuosity effect. Expressions for integrated convergence factor for crushed rocks and glass spheres are Cfi = 1.095 d - 0.079 and Cfi = 0.802 d - 0.25 respectively

Generation of Groundwater Quality Index Map: A Case Study

Reliance on groundwater has been rapidly increasing, especially in the arid and semiarid regions, resulting in its overexploitation leading to deterioration of quality. Kurmapalli Vagu basin of Andhra Pradesh, a semi-critical region with respect to the stage of groundwater development is a good example. Its monitoring and assessment is imperative for devising preventive measures against health hazards. Groundwater samples from twenty five locations were collected and analyzed for various physico-chemical parameters in terms of Water Quality Index (WQI) to determine its suitability for drinking purposes. Seven locations were found to have WQI value within the limits. High values of WQI were mostly due to high content of Fluorides. WQI Contour map was generated to study spatial distribution of quality of groundwater. Suitable remedial measures and groundwater augmenting structures are proposed in the study area to improve the quality of groundwater. Keywords: Groundwater, WQI, Fluorosis, Groundwater augmenting structures

Automated minimization of steric clashes in protein structures

Molecular modeling of proteins including homology modeling, structure determination, and knowledge-based protein design requires tools to evaluate and refine three-dimensional protein structures. Steric clash is one of the artifacts prevalent in low-resolution structures and homology models. Steric clashes arise due to the unnatural overlap of any two non-bonding atoms in a protein structure. Usually, removal of severe steric clashes in some structures is challenging since many existing refinement programs do not accept structures with severe steric clashes. Here, we present a quantitative approach of identifying steric clashes in proteins by defining clashes based on the Van der Waals repulsion energy of the clashing atoms. We also define a metric for quantitative estimation of the severity of clashes in proteins by performing statistical analysis of clashes in high-resolution protein structures. We describe a rapid, automated and robust protocol, Chiron, which efficiently resolves severe clashes in low-resolution structures and homology models with minimal perturbation in the protein backbone. Benchmark studies highlight the efficiency and robustness of Chiron compared to other widely used methods. We provide Chiron as an automated web server to evaluate and resolve clashes in protein structures that can be further used for more accurate protein design

Gaia: automated quality assessment of protein structure models

Motivation: Increasing use of structural modeling for understanding structure–function relationships in proteins has led to the need to ensure that the protein models being used are of acceptable quality. Quality of a given protein structure can be assessed by comparing various intrinsic structural properties of the protein to those observed in high-resolution protein structures

Modelling of the Electric Vehicle Charging Infrastructure as Cyber Physical Power Systems: A Review on Components, Standards, Vulnerabilities and Attacks

The increasing number of electric vehicles (EVs) has led to the growing need to establish EV charging infrastructures (EVCIs) with fast charging capabilities to reduce congestion at the EV charging stations (EVCS) and also provide alternative solutions for EV owners without residential charging facilities. The EV charging stations are broadly classified based on i) where the charging equipment is located - on-board and off-board charging stations, and ii) the type of current and power levels - AC and DC charging stations. The DC charging stations are further classified into fast and extreme fast charging stations. This article focuses mainly on several components that model the EVCI as a cyberphysical system (CPS)