On solute dispersion from an elevated line source in an open-channel flow

The streamwise dispersion of contaminant molecules due to a turbulent shear flow over a gravel-bed surface is examined when the solute is released from an elevated line source. A finite-difference, implicit method is used to solve the unsteady turbulent convection-diffusion equation, employing a combined scheme of central and four-point upwind differences for the steady-state condition and the Alternating Direction Implicit (ADI) method for the unsteady equation. It is shown how the mixing of contaminant is effected by the mean velocity due to the `log-wake law' and the corresponding eddy-diffusivity, when the solute is released in terms of a -function. The results for the steady-state condition are compared with existing experimental data and some other numerical results. The results obtained by the present method are in much better agreement with the experimental data than those obtained by the previous solution scheme, when the `log-wake-law' and the corresponding eddy-diffusivity are used. Far from the source, the concentration increases with time (the rate of increase is rapid near the source), asymptotically approaching a steady state after a certain time; concentrations are about two thirds of those near the source. The behaviour of iso-concentration lines in the vertical plane is also studied.     

Design and development of a safer non-invasive transungual drug delivery system for topical treatment of onychomycosis

Objective: The main objective of this study is to develop a safer non-invasive treatment for nail infections since the current treatment regimen has drawbacks like, incidence of systemic side-effects and higher cost. Proposed topical treatment on the other hand can drastically improve the situation, hence highly desirable. This work was undertaken with a hypothesis to develop a transungual microemulsion gel for topical treatment of onychomycosis.

Methods: Benzyl alcohol and isopropyl myristate were used as oil, Pluronic F68 as surfactant and ethanol as co surfactant, in double-distilled water and loading itraconazole as the model antifungal drug. Pseudo-ternary phase diagram was developed by titrating different ratios of total oil and water with total surfactant, and K_m ratio was fixed at 1:1. Microemulsion formulations were prepared based on the phase diagram and incorporated in gels by adding Carbopol 934P. Nail permeation enhancers like urea and salicylic acid were used to increase drug permeation through the nail plate. Parameters like drug loading, clarity, particle size distribution, drug entrapment efficiency (DEE), drug release profile, release kinetics and nail uptake were checked for the evaluation of the formulations.

Results: Complete release of drug from the formulation varied from 60 to 120?min. The optimized formulation had DEE of 92.75%, complete drug release in 60?min and highest nail uptake of 0.386%/mm² (39?µg of drug) with 5% urea as nail permeation enhancer.

Conclusion: The formulation may prove beneficial in safer treatment of onychomycosis.     

A comparative study of microstructure and mechanical behavior of CO2 and diode laser deposited Cu–38Ni alloy

Cu–38Ni alloy was deposited on C71500 (Cu–30Ni) substrates by a laser-aided direct metal deposition technique using CO₂ and diode lasers. Structure–property relationships of deposited specimens were investigated by optical microscopy, electron microscopy, X-ray diffraction techniques, and microhardness and tensile measurements. Laser-deposited specimens’ microstructures were primarily dendritic, forming columnar grains growing epitaxially from the substrate and subsequent layers along the preferred crystallographic growth. The grain growth pattern and grain size distribution was significantly different in both specimens. The lattice parameter of the solid solution phase was relatively larger in diode laser-formed specimen; CO₂ laser-formed specimens showed relatively higher but non-uniform hardness distribution whereas a very uniform hardness distribution was observed in diode laser formed specimens. Diode laser formed specimens showed higher tensile properties compared to CO₂ laser formed specimens which were comparable to C71500 substrates. Microstructure and mechanical behavior were explained based on laser processing parameters.     

Estimation of the Park-Ang damage index for planar multi-storey frames using equivalent single-degree systems

A detailed characterization of potential structural damage is essential to performance-based seismic design. The Park-Ang damage index is selected in this work as the seismic damage measure, since it is one of the most realistic measures of structural damage. Response spectra constitute the most common tool used for characterizing the seismic hazard at a site, and these spectra represent the demand on single-degree oscillators. To use these spectra for estimating the Park-Ang damage index demand on an MDOF system, three equivalent single-degree system-based approximate schemes are proposed. These schemes are tested on three moment resisting frames under several ground motion scenarios. The effectiveness of an equivalent system scheme is measured by comparing with the estimates from a nonlinear response-history analysis of the MDOF model. These schemes are tested for both global and storey-level damage indices. Variation of the non-dimensional parameter β is also considered in these case studies. Overall, all the three schemes are found to be effective with varying degrees of accuracy. The proposed methods are recommended for damage-based seismic design and performance evaluation of structures because these schemes can use response spectra for demand estimation and reduce computation cost.     

Effectiveness of combinations of raft foundation with aprons as a protection measure against bridge pier scour

Scour around bridge pier is the main reason for the failure of bridges. The local scour around the pier causes exposure of the foundation and may lead to undermining of the structure. Different types of protection measures such as the provision of raft, apron, sheet piles, etc. can be used as scour protection measures. One of the possible effective bridge scour protection measures is to provide a raft foundation with cut-off walls and provision of flexible stone aprons towards upstream (u/s) and downstream (d/s) sides of the pier. In this study, the effectiveness of various bridge pier scour protection measures using raft and aprons is investigated through hydraulic model studies in the laboratory. The results are compared for various cases, such as a simple pier, pier with raft and extended raft, pier resting on a raft with stone aprons at u/s and d/s of the raft and pier resting on an extended raft with stone aprons on u/s and d/s of it. The comparison of various cases showed that rigid raft with stone aprons on u/s and d/s and extended raft with apron are found to be more effective in reducing immediate scour beyond the rigid raft, thereby giving protection to the bridge piers.     

Event prediction with rough-fuzzy sets

Pattern Analysis and Applications - This article proposes a new methodology of unsupervised event prediction from videos. Detecting events from videos without prior information is a challenging...     

Machine learning-based accelerated design of fluorphlogopite glass ceramic chemistries with targeted hardness

In this work, we develop and employ an accelerated design strategy using a machine learning algorithm to overcome the challenges for designing a new machinable glass ceramic. The trained machine learning model predicts the specific hardness value for numerous possibilities of processing conditions such as growth temperature and time. We report that the optimized growth parameters of 1200°C and 5 h achieve the highest machinability of 0.4 in the glass ceramic. Furthermore, we predicted the eight most promising candidates containing specific ratios of silicon, magnesium, aluminum, lithium, boron, potassium, barium, and oxygen. Combining machine learning with experimental data enables a systemic and rapid design of a ceramic material while capturing the underlying physics represented in the experimental data.