Diffraction on birefringent elements with sine surface microrelief

Abstract— Light diffraction on optically anisotropic substrates using sine surface microrelief has been calculated by using the OAGSM method. The influence of the microrelief depth and material birefringence on the diffraction intensity on the order of 0–3 is reviewed and discussed. The results are compared with the results of the calculation for a rectangular microrelief. The microrelief depth and material birefringence allows the realization of different polarization states of the light beam transmitted or reflected by the substrate. The approach can be used to control the light‐beam propagation for different applications including LCD backlights.     

Describing and quantifying the chemical composition distribution in unimodal and multimodal ZN‐polyethylene using CRYSTAF

A new approach in describing and quantifying the chemical composition distribution (CCD) in Ziegler–Natta‐polyethylene copolymers was developed by using crystallization analysis fractionation (Crystaf). Copolymers of ethylene and α‐olefins (1‐butene and 1‐hexene) polymerized with different ZN catalyst systems were analyzed. Distinct differences in the CCD between the different polymer types (catalyst‐cocatalyst system and comonomer type) were observed and could be quantified. Same approach was applied to 2‐dimensional fractionation technique, cross fractionation chromatography, to describe and quantify the CCD of multimodal polyethylene copolymers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43089.     

Process development for spray drying a value‐added extract from aflatoxin‐contaminated peanut meal

Peanut meal, the primary by‐product of commercial oil crushing operations, is an excellent source of protein although aflatoxin contamination often limits applications for this material. Naturally aflatoxin‐contaminated (59 ppb) peanut meal dispersions were adjusted to pH 2.1 or pH 9.1, with or without additional protease and/or a clay absorbent, and the resulting soluble extracts derived from these dispersions were spray dried. Clay addition during processing minimally affected spray‐drying yields, protein powder solubility or antioxidant capacities, whereas these properties were significantly altered by pH and protease treatments. Spray‐dried hydrolysates produced from peanut meal treated with clay contained significantly less aflatoxin than hydrolysates produced without clay; the effects of pH or enzyme on aflatoxin content were minimal. Peanut meal treated with Alcalase, and clay yielded spray‐dried hydrolysates with enhanced antioxidant capacity and increased solubility compared to unhydrolysed controls and had aflatoxin levels below 1 ppb.     

Flexural-gravity waves due to unsteady motion of point source under a floating plate in fluid of finite depth

The paper deals with the theoretical investigation of the straight unsteady motion of a point source submerged into the liquid of finite depth below the floating ice plate. The formulae describing the plate deflection and obtained with the help of integral and asymptotic methods are numerically analyzed with respect to velocity and submergence depth of point source, basin depth, ice plate thickness and Young’s modulus.

     

Self-diffusion in solutions of carboxylated acrylic polymers as studied by Pulsed Field Gradient NMR. 2. Diffusion of macromolecules

The diffusion constants of carboxylated acrylic copolymers in isopropanol (IPA) have been investigated using the PFG NMR technique. A range of compositions of butyl methacrylate and methacrylic acid random copolymers (BMA–MAA 100/0 through to 60/40 in 10 mol% steps) have been studied. The polymer diffusivity is two orders of magnitude slower than that for the solvent. A maximum value of G _max = 10 T/m for the gradient pulse was used to suppress solvent signal and to measure the low value of the self-diffusion coefficient for the polymers. Polymer diffusion studies at different diffusion times showed that the diffusion constant decreased with increasing diffusion time. The influence of the concentration on the polymer aggregation in solution and the influence of the BMA/MAA molar ratio on the diffusion constants of the polymer have been studied. The diffusion constant for the polymer at long diffusion times increased with mol% BMA which is similar to the short diffusion time studies. The data obtained have been discussed using published results and models for “anomalous diffusion” of macromolecules in polymer solutions.     

Tailoring engineered cementitious composites for impact resistance

This paper presents results of deliberate tailoring of engineered cementitious composites (ECC) for impact resistance. Microstructure control involving fiber, matrix and fiber/matrix interface was based on steady-state dynamic crack growth analyses accounting for rate dependence of composite phases. Uniaxial tensile stress–strain curves of the resulting impact resistant ECC were experimentally determined for strain rates ranging from 10^? 5 s^? 1 to 10^? 1 s^? 1. Low speed drop weight tower test on ECC panels and beams was also conducted. Damage characteristics, load and energy dissipation capacities, and response to repeated impacts, were studied.     

Aqueous colloidal processing of SiC with Y3Al5O12 liquid-phase sintering additives

The aqueous colloidal processing of SiC with Y₃Al₅O₁₂ liquid-phase sintering additives was investigated for two different additive systems, one the mixture of Y₂O₃ and Al₂O₃ in a 3:5 molar ratio and the other directly Y₃Al₅O₁₂. The investigation involved the study of the colloidal stability of the different components, and the comparison of the rheological behaviour of concentrated suspensions of SiC, SiC + 3Y₂O₃:5Al₂O₃, and SiC + Y₃Al₅O₁₂ as a function of the sonication condition, dispersant content, and solid loading. This allowed appropriate conditions for the preparation of well-dispersed, single-phase, and multi-component concentrated suspensions of SiC to be identified. It was found that the multi-component suspensions have better rheological behaviour than the single-phase ones, and that in terms of rheology and slip casting the Y₃Al₅O₁₂ additives are more functional than the conventional 3Y₂O₃ + 5Al₂O₃ additives. It was also demonstrated that the Y₃Al₅O₁₂ additive is as effective as the 3Y₂O₃ + 5Al₂O₃ additive in densifying SiC via liquid-phase sintering, with there existing no differences either in the microstructure or in room-temperature mechanical properties (hardness, toughness, and fracture mode). Implications of interest for the wet-shaping of complex SiC parts are discussed.     

Theoretical and experimental analysis of droplet evaporation on solid surfaces

The evaporation of sessile drops is central to a number of important processes, including printing, washing and coating. In this paper, the evaporation of water sessile droplets on hydrophobised silicon wafers and Teflon was analysed from theoretical and experimental perspectives. The contact angle, volume and base radius of the water droplets as a function of time were determined using tensiometry. The theoretical analysis showed different evaporative flux phenomena for acute and obtuse contact angles. The non-linear evolution of residual droplet volume, contact angle and base radius are solved and depend on the hydrophobicity of the solid surface and droplet dimension. Good agreement between the theoretical and experimental results was observed during pinning and depinning stages of evaporation. It was shown that the surface roughness, hydrophobicity and the contact angle hysteresis significantly influenced the evaporation of sessile drops and need to be considered when quantifying the evaporation process.     

Oxidative Stress Mediates the Disruption of Airway Epithelial Tight Junctions through a TRPM2-PLCγ1-PKCα Signaling Pathway

Oxidative stress has been implicated as an important contributing factor in the pathogenesis of several pulmonary inflammatory diseases. Previous studies have indicated a relationship between oxidative stress and the attenuation of epithelial tight junctions (TJs). In Human Bronchial Epithelial-16 cells (16HBE), we demonstrated the degradation of zonula occludens-1 (ZO-1), and claudin-2 exhibited a great dependence on the activation of the transient receptor potential melastatin (TRPM) 2 channel, phospholipase Cγ1 (PLCγ1) and the protein kinase Cα (PKCα) signaling cascade.