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Wave force acting on a circular flexible plate in the presence of a vertical surface-piercing flexible porous membrane is examined under the hypothesis of linear water wave theory. A semi-analytic solution is developed employing the Fourier-Bessel series expansion method along with the methods of separation of variables and least-squares approximation. To keep the outer flexible membrane at a desired position, clamped-moored condition is used. Appropriate orthogonal mode-coupling relationship for the eigenfunctions of the plate covered region is exploited in the expansion formulas together with the continuity of velocity and pressure for achieving the system of equations and to determine the unknowns. The effects of various physical parameters are analyzed by computing wave load on the structures, plate deflection and flow distribution. It is found that due to the presence of vertical flexible porous membrane, a significant amount of wave force on the plate is reduced. Thus, a cylindrical flexible porous membrane can be implemented to protect the inner circular flexible plate. [ABSTRACT FROM AUTHOR]

The effect of a floating elastic membrane on a gravity‐driven flow down an inclined porous plane is examined. The present work extends the earlier work of Anjalaiah et al. [Phys. Fluid, Vol. 25, 022101 (2013)] by including the thin membrane and excluding the insoluble surfactant at the top surface of the flow. The membrane tension emergence from the elasticity, is used to monitoring the surface tension on the top surface of the fluid layer. The fluid flow below the elastic membrane is governed by the Navier–Stokes equations and flow through the porous medium is governed by the Darcy–Brickmann equations. Using the normal mode analysis, two Orr–Sommerfeld systems are derived for each layers and solved by using the spectral collocation method to capture the linear instability. Further, the temporal growth rate and marginal stability curve are analyzed for different set of structural parameters. In general, the instability of free surface flow is more due to the presence of the unstable Yih mode. Both, the membrane tension and the uniform mass distribution rate along the length of the membrane assure to stabilize the surface waves by lowering the temporal growth rate of the disturbances. Consequently, the floating elastic membrane and the porosity of the inclined substrate pretend to suppress the unstable Yih mode and stabilize the flow anatomy. Hence, the floating elastic membrane can be disposed for the lethargic control of the free‐surface flows' instability. [ABSTRACT FROM AUTHOR]

Wave interaction with multiple bottom-standing rectangular porous structures of different structural parameters is numerically modeled using the multidomain boundary element method and the matched eigenfunction expansion method, while assuming linear water wave theory. The sensitivity of wave reflection and transmission to the wave and structural parameters is analyzed with the objective to maximize wave energy attenuation. Different configurations of multiple structures are tested for maximizing the efficiency of dissipation. Furthermore, wave trapping by multiple porous structures near a sloping rigid wall is studied. Bragg resonance is observed in the case of wave scattering by multiple structures irrespective of wave and structural parameters and is found as proportional to the number of structures deployed. In addition, the study reveals that in the presence of multiple structures, due to more wave energy dissipation, wave transmission in the lee side of the structures is reduced significantly when compared with that observed for a single structure. [ABSTRACT FROM AUTHOR]

Pillar[n]arene, a new class of macrocycle was first introduced in the year 2008. Since then, it has gained much attention in supramolecular chemistry. The structural simplicity combined with its straightforward synthesis through one‐step reaction process paves the way to develop various functionalized materials. The electron‐rich cavities of pillar[n]arene attached to suitable functional groups have been extensively used for various applications. This report will be focused on the challenges to engineer pillar[n]arene scaffold to get functionalized materials, potential applications and their future scope. [ABSTRACT FROM AUTHOR]

Understanding the determinants of permeability and selectivity in biological channels serves two general purposes. It provides fundamental biophysical insights and allows the evaluation of new membrane proteins and artificial channel designs for the development of biomimetic separation membranes. This understanding relies on accurate ways to quantify unitary (single channel) solute and solvent permeabilities. However, the current research in biomimetic and bioinspired membranes and in protein biophysics tends to focus on relative permeabilities. Further, many methods and approximations currently used result in erroneous permeability values which hinder and complicate the comparison between channels. Combined, these gaps in the available measurements obscure the biophysical insights and impede the development of novel high-performance channels. In this review, we summarize in vitro model membrane systems useful to functionally characterize artificial as well as biological channels. We also critically discuss biophysical techniques capable of extracting permeability values and membrane channel densities, which are fundamental parameters required to determine accurate unitary permeability values. Pertinent examples are provided, along with advantages, disadvantages, and potential improvements needed for specific techniques to acquire accurate unitary permeability values for a diverse set of small molecules, including water, ions, weak acids and bases, neutral molecules, and protons. [Display omitted] • Membrane proteins and their artificial mimics are important for biology and engineering. • Accurate unitary solute and solvent permeabilities are important benchmarks. • Biophysical quantification methods can help to improve membranes for separations. • Artificial channel performance can be benchmarked to model membrane proteins. [ABSTRACT FROM AUTHOR]

Protein pores that selectively transport ions across membranes are among nature's most efficient machines. The selectivity of these pores can be exploited for ion sensing and water purification. Since it is difficult to reconstitute membrane proteins in their active form for practical applications it is desirable to develop robust synthetic compounds that selectively transport ions across cell membranes. One can envision tuning the selectivity of pores by incorporating functional groups inside the pore. Readily accessible octapeptides containing (aminomethyl)benzoic acid and alanine are reported here that preferentially transport cations over halides across the lipid bilayer. Ion transport is hypothesized through pores formed by stable assemblies of the peptides. The aromatic ring(s) appear to be proximal to the pore and could be potentially utilized for functionalizing the pore interior., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)