Groundwater Circulation Well for Controlling Saltwater Intrusion in Coastal aquifers: Numerical study with Experimental Validation

Saltwater intrusion into coastal aquifers has become a prominent environmental concern worldwide. As such, there is a need to prepare and implement proper remediation techniques with careful planning of freshwater withdrawal systems for controlling saltwater intrusion in coastal marine and estuarine environments. This paper investigates the performance of groundwater circulation well (GCW) in controlling saltwater intrusion problems in unconfined coastal aquifers. The GCWs have been established as a promising in-situ remedial technique of contaminated groundwater. The GCW system creates vertical circulation flow by extracting groundwater from an aquifer through a screen in a single well and injecting back into the aquifer through another screen. The circulation flow induced by GCW force water in a circular pattern between abstraction and recharge screens and can be as a hydraulic barrier for controlling saltwater intrusion problem in coastal aquifers. In this study, an effort has been made to investigate the behavior of saltwater intrusion dynamics under a GCW. An experiment has been conducted in a laboratory-scale flow tank model under constant water head boundary conditions, and the variable-density flow and transport model FEMWATER is used to simulate the flow and transport processes for the experimental setup. The evaluation of the results indicates that there is no further movement of saltwater intrusion wedge towards the inland side upon implementation of GCW, and the GCW acts as a hydraulic barrier in controlling saltwater intrusion in coastal aquifers. The present study reveals the GCWs system can effectively mitigate the saltwater intrusion problem in coastal regions and could be considered as one of the most efficient management strategies for controlling the problem.

     

Photovoltaic effect in single-layer organic solar cell devices fabricated with two new imidazolin-5-one molecules

Organic solar cells were fabricated with two new imidazolin-5-one molecules as active layers. The use of imidazolin-5-ones, derivatives of a biomolecule chromophore, for photovoltaic applications is particularly attractive due to its biodegradable nature and tunable properties. Single-layer devices with two analogues of imidazolin-5-ones were prepared and characterized. Devices fabricated with one of the molecules as the active layer showed a maximum J_sc of 0.52 μA cm⁻² and V_oc of 0.68 V at an incident power of 20.32 mW cm⁻², while the other set of devices showed a maximum J_sc of 0.63 μA cm⁻² and V_oc of 0.57 V at the same incident power.     

Ultra-Short Cyclized β-Boomerang Peptides: Structures,Interactions with Lipopolysaccharide,Antibiotic Potentiator and Wound Healing

Many antibiotics are ineffective in killing Gram-negative bacteria due to the permeability barrier of the outer-membrane LPS. Infections caused by multi-drug-resistant Gram-negative pathogens require new antibiotics, which are often difficult to develop. Antibiotic potentiators disrupt outer-membrane LPS and can assist the entry of large-scaffold antibiotics to the bacterial targets. In this work, we designed a backbone-cyclized ultra-short, six-amino-acid-long (WKRKRY) peptide, termed cWY6 from LPS binding motif of β-boomerang bactericidal peptides. The cWY6 peptide does not exhibit any antimicrobial activity; however, it is able to permeabilize the LPS outer membrane. Our results demonstrate the antibiotic potentiator activity in the designed cWY6 peptide for several conventional antibiotics (vancomycin, rifampicin, erythromycin, novobiocin and azithromycin). Remarkably, the short cWY6 peptide exhibits wound-healing activity in in vitro assays. NMR, computational docking and biophysical studies describe the atomic-resolution structure of the peptide in complex with LPS and mode of action in disrupting the outer membrane. The dual activities of cWY6 peptide hold high promise for further translation to therapeutics.     

Optimal Management of Coastal Aquifers Using Linked Simulation Optimization Approach

Saltwater intrusion management models can be used to derive optimal and efficient management strategies for controlling saltwater intrusion in coastal aquifers. To obtain physically meaningful optimal management strategies, the physical processes involved need to be simulated while deriving the management strategies. The flow and transport processes involved in coastal aquifers are difficult to simulate especially when the density-dependent flow and transport processes need to be modeled. Incorporation of this simulation model within an optimization-based management model is very complex and difficult. However, as an alternative, it is possible to link a simulation model externally with an optimization-based management model. The GA-based optimization approach is especially suitable for externally linking the numerical simulation model within the optimization model. Further efficiency in computational procedure can be achieved for such a linked model, if the simulation process can be simplified by approximation, as very large number of iterations between the optimization and simulation model is generally necessary to evolve an optimal management strategy. A possible approach for approximating the simulation model is to use a trained Artificial Neural Network (ANN) as the approximate simulator. Therefore, an ANN model is trained as an approximator of the three dimensional density-dependent flow and transport processes in a coastal aquifer. A linked simulation – optimization model is then developed to link the trained ANN with the GA-based optimization model for solving saltwater management problems. The performance of the developed optimization model is evaluated using an illustrative study area. The evaluation results show the potential applicability of the developed methodology using a GA- and ANN-based linked optimization – simulation model for optimal management of coastal aquifer.     

Establishing and validating secured keys for IoT devices: using P3 connection model on a cloud-based architecture

International Journal of Information Security - IoT devices are slowly turning out to be an essential part of our everyday lives. These devices perform one operation, and they specialize in doing...     

Thanatin: An Emerging Host Defense Antimicrobial Peptide with Multiple Modes of Action

Antimicrobial peptides (AMPs) possess great potential for combating drug-resistant bacteria. Thanatin is a pathogen-inducible single-disulfide-bond-containing β-hairpin AMP which was first isolated from the insect Podisus maculiventris. The 21-residue-long thanatin displays broad-spectrum activity against both Gram-negative and Gram-positive bacteria as well as against various species of fungi. Remarkably, thanatin was found to be highly potent in inhibiting the growth of bacteria and fungi at considerably low concentrations. Although thanatin was isolated around 25 years ago, only recently has there been a pronounced interest in understanding its mode of action and activity against drug-resistant bacteria. In this review, multiple modes of action of thanatin in killing bacteria and in vivo activity, therapeutic potential are discussed. This promising AMP requires further research for the development of novel molecules for the treatment of infections caused by drug resistant pathogens.     

Rectangular MgO microsheets with strong catalytic activity

Rectangular hydromagnesite microsheet is prepared by simple solution route through controlled hydrolysis-condensation of magnesium chloride in urea solution using ethylene glycol (EG) as a bifunctional cosolvent. Calcination of the hydromagnesite sheets at 450 °C produces MgO without any alteration in the morphology. The MgO sheets were of 2–3 μ side length and 4–5 nm thickness, and made of highly crystalline MgO nano-particles, which show reasonably high BET surface area of 106 m² g⁻¹. These MgO microsheets showed very strong activity as heterogeneous base catalyst in the solvent free Claisen–Schmidt condensation of benzaldehyde with acetophenone giving 99.0% conversion in less than 4 h with almost no loss of activity in three successive cycles. The strong activity is correlated with its large surface area and presence of oxide ions in low coordination (LC) O_LC²⁻ (where LC = 5C, 4C and 3C for terrace, edge, corner and kink sites, respectively) along with defects, which was revealed by photoluminescence (PL) emission studies. Presence of basic sites of different strength, determined by temperature programmed desorption of carbon dioxide (TPD-CO₂) also supports the strong catalytic activity of the MgO micro-sheets. Increase in calcination temperature to 650 °C destroys the open sheet morphology and enhances crystallite size, which causes decrease in catalytic activity due to low surface area, constrain in mass transport from the core structure and low concentration of active basic sites.     

A highly efficient carbon-supported Pt electrocatalyst prepared by γ-irradiation for cathodic oxygen reduction

A simple, efficient and scalable approach is developed for synthesis of Vulcan XC-72(carbon)-supported Pt nanoparticles (NPs) that combines homogeneous deposition (HD) of Pt complex species through reaction with OH^- ions generated by in situ hydrolysis of urea and subsequent reduction by reducing species generated from radiolysis of water by γ-rays. This method not only avoids addition of any commonly used reducing agent, but also offers more uniform homogeneous dispersion of Pt NPs with much smaller particle size. Thus, when used as a cathode catalyst for proton exchange membrane fuel cell, the synthesized carbon-supported Pt NPs demonstrate excellent oxygen reduction electro–catalytic activity, higher Pt utilization efficiency, and considerably improved fuel cell polarization performance compared to those of Pt catalysts prepared with other synthesis strategies such as conventional NaBH₄ reduction and HD-ethylene glycol method as well as commercial Pt catalyst. The combined HD-γ-irradiation strategy is found to be simple, reproducible and efficient with mild synthesis condition and in particular, holds great promises for large scale production of highly efficient Pt-based catalysts for fuel cells.     

Joint solution of low, intermediate, and high-level vision tasks byevolutionary optimization: Application to computer vision at lowSNR

Methods for conducting model-based computer vision from low-SNR (=/<1 dB) image data are presented. Conventional algorithms break down in this regime due to a cascading of noise artifacts, and inconsistencies arising from the lack of optimal interaction between high- and low-level processing. These problems are addressed by solving low-level problems such as intensity estimation, segmentation, and boundary estimation jointly (synergistically) with intermediate-level problems such as the estimation of position, magnification, and orientation, and high-level problems such as object identification and scene interpretation. This is achieved by formulating a single objective function that incorporates all the data and object models, and a hierarchy of constraints in a Bayesian framework. All image-processing operations, including those that exploit the low and high-level variables to satisfy multi-level pattern constraints, result directly from a parallel multi-trajectory global optimization algorithm. Experiments with simulated low-count (7-9 photons/pixel) 2-D Poisson images demonstrate that compared to non-joint methods, a joint solution not only results in more reliable scene interpretation, but also a superior estimation of low-level imaging variables. Typically, most object parameters are estimated to within a 5% accuracy even with overlap and partial occlusion.     

TTCBT: two tier complete binary tree based wireless sensor network for FSR and LANMAR routing protocols

Microsystem Technologies - Wireless sensor network is extensively used for monitoring and surveillance systems. The primary challenges encountered in the area are energy minimization as well as...