A weight-function approach for determining watershed initial conditions for combustion waves

In many generic combustion models, one finds that a combustionwave will develop with a specific wave speed. However, thereare possible initial temperature profiles which do not evolveinto such waves, but rather die out to the ambient temperature.There can exist, in some models, a clear distinction betweenthose initial conditions that do evolve into combustion wavesand those that do not; this is sometimes referred to as thewatershed initial condition. When fuel consumption is consideredto be negligible, analytical methods can be used to obtain theexact watershed. In this paper, we consider the problem of determiningpseudo-watersheds and ascertaining the relationship betweenthese pseudo-watersheds and the exact watersheds. In the processa novel weight-function approach for infinite spatial domainsis developed.     

Block copolymer solution self-assembly: Recent advances,emerging trends,and applications

The self-assembly process of block copolymers (BCPs) in solution has been at the focus of extended scientific research over the past several decades owing to the astonishing morphological diversity and attainable complexity of the resulting nanoassemblies, including spheres, cylinders, lamellae, vesicles, and many other complex, bicontinuous or even hierarchical structures. The ever-increasing sophistication in the development of synthetic chemistry methods and techniques has led to a myriad of available macromolecules with varying chemical compositions, architectures, features, and properties. This assortment of characteristics has led in turn to a plethora of intriguing self-organized polymeric nanostructures, with countless possible applications in several nanotechnological fields relevant to physics, chemistry, material science, nanomedicine, and biomaterials. The present review aims to illuminate the importance and fascinating potential of BCPs solution self-assembly by highlighting recent advances and emerging trends in the field, as well as significant application-oriented progress, through characteristic contemporary examples.     

Oxide density distribution across the barrier layer during the steady state growth of porous anodic alumina films: chronopotentiometry, kinetics of mass and thickness evolution and a high field ionic migration model

The steady state growth of porous anodic alumina films in oxalate solutions at various conditions was studied by chronopotentiometry, mass balance and optical microscopy methods enabling determination of consumed Al, film mass and thickness, current efficiencies, Al³⁺ and O²⁻ transport numbers across barrier layer, etc. The film thickness growth rate was found to be proportional to O²⁻ anionic current. A high field ionic migration model was developed. It predicted that, during anodising, the local oxide density across barrier layer rises from 2.6 in Al|oxide to 4.59–5.22 g cm⁻³ in oxide|electrolyte interface with mean value ≈3.21–3.52 g cm⁻³. The field strength rises from the first to second interface. The mechanism of Al oxidation near the Al|oxide interface embraces the transformation of the Al lattice to a transient, rare oxide one sustained by field with comparable Al³⁺ spacing parameter. The oxide near the Al|oxide interface and around the density maximum in the oxide|electrolyte interface are under different levels of electro-restriction stresses. During relaxation, the oxide behaves like a solid-fluid material suppressing the initial density distribution.     

Electrostatic complexation of a double hydrophilic block polyelectrolyte and proteins of different molecular shape

The electrostatic complexation between the polyelectrolyte block of the novel double hydrophilic copolymer quaternized poly(3,5‐bis(dimethylaminomethylene) hydroxystyrene)‐b‐poly(ethylene oxide) (QNPHOS‐PEO) and proteins of different molecular shape, that is globular bovine serum albumin (BSA) or rod‐like bovine fibrinogen (FBG), is investigated by means of dynamic, static, and electrophoretic light scattering, as well as analytical ultracentrifugation measurements. The solution behavior, structure, and properties of the formed complexes at pH 7 and 0.01 M ionic strength, as a function of the protein concentration in the solution (or equivalently the charge ratio of the two components), depend on the protein concentration and molecular characteristics. Moreover, the structure of the complexes is greatly influenced by the intrinsic structure of the block polyelectrolyte, which forms rather loose multichain aggregates, due to hydrophobic interactions. A direct correlation between the stability of the preformed complexes against the increase of the solution ionic strength and their structure is established. Finally, the spectroscopic structural investigation of both complexed proteins reveals no signs of protein denaturation upon complexation. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1515–1529     

An insight into the disorder properties of the α-cyclodextrin polyiodide inclusion complex with Sr2+ ion: dielectric,DSC and FT-Raman spectroscopy studies

At T < 250 K, the polyiodide inclusion complex (α-cyclodextrin)₂·Sr_0.5·I₅·17H₂O displays two separate relaxation processes due to both the frozen-in proton motions in an otherwise ordered H-bonding network and the order–disorder transition of some normal H-bonds to flip-flop ones. At T>250 K, the AC-conductivity is dominated by the combinational contributions of the disordered water network, the mobile Sr²⁺ ions, the polyiodide charge-transfer interactions and the dehydration process. The evolution of the Raman spectroscopic data with temperature reveals the coexistence of four discrete pentaiodide forms. In form (I) (I^?  ₃·I₂ ? I₂·I^?  ₃), the occupancy ratio (x/y) of the central I^?  ion differs from 50/50. In form (IIa) (I₂·I^? ·I₂) x/y = 50/50, whereas in its equivalent form (IIb) (I₂·I^? ·I₂) ^* as well as in form (III) (I^?  ₃·I₂), x/y = 100/0 (indicative of full occupancy). Through slow cooling and heating, the inverse transformations (I) → (IIa) and (IIa) → (I) occur, respectively.