Adapting the ionic transfer behavior of cation exchange membrane incorporated with SiO2/PAA composite nanoparticles

Ionics - In this study, silicon dioxide nanoparticles (SiO2 NPs) were functionalized by polyacrylic acid (PAA) then used as the modifier agent in polyvinyl chloride (PVC)-based heterogeneous cation...     

Utilization of coir fiber in multilayer acoustic absorption panel

Coconut is one of the most important harvests in Malaysia. Industrial prepared coir fiber is obtained from coconut husk combined with latex and other additives to enhance its structural characteristics. Unfortunately, such inevitable process diminishes the acoustical features of material. Previous studies on industrial coir fiber and fiber-air gap layers showed that low frequency absorptions needed improvements. Therefore perforated plate (PP) was added to the multilayer structure to further enhance the sound absorption in this area. Analyses were accomplished through three PP modeling approaches (Allard, Beranek and Ver, Atalla and Sgard) and Allard Transfer Function (TF) method. Experiments were conducted in impedance tube to support the analytical results. Outcomes showed that Allard TF method was generally closer to measurement values and implemented for additional analyses. Two possible conditions of putting PP in front of fiber layer or between fiber-air gap layers were investigated. Both arrangements were suitable to enhance the sound absorption. Although, when PP was backed by coir fiber and air gap, porosity of the plate had great influence in adjusting the amount of low frequency absorption. Result derived that PP might improve the low frequency absorption of coir fiber but at the same time the medium frequency absorption was reduced. This effect was noticed previously in coir fiber-air gap structures while the air gap thickness increased. The advantage of using PP was that it assisted in greatly reducing the air gap thickness under the same acoustical performance. Hence it is an efficient tool to reduce the thickness of acoustic isolators in practical purposes.     

The correlations between processing parameters and magnetic properties of an iron–resin soft magnetic composite

In this study, internal microstrain of an iron–resin composite produced by powder metallurgy has been calculated using the Williamson–Hall method. The effects of microstrain evolution during different processing conditions on magnetic properties such as coercive force and hysteresis loss have been investigated. The results show that there are regular and similar changes of coercivity and hysteresis loss. Both of these properties are directly dependant on the pinning effect of the internal microstrain against the movement of magnetic domain walls during magnetization process.     

Optical transmission and reflection of aluminum film irradiated by nanosecond laser beam and experimental studying of phase-explosion

In this paper we present evidence for a phase explosion during the laser-induced ablation process by studying the optical reflectivity of the ablated plume. The ablation was produced by irradiating thin film aluminum coated on a quartz substrate with a single pulse laser beam in ambient air. The laser pulse was provided by the second harmonic of a Q-switched Nd:YAG laser with ∼10 ns pulse duration. The transmission of a low power He–Ne laser beam through the hot ablated material plume and its reflection (from the front surface, and rear surface of aluminum film) were also monitored during the duration of the ablation event. The results show that the front surface reflectivity is enhanced at an early time of ablation which is described as strong evidence for the creation of a phase explosion in this process.     

CuI–Ionic Liquids as Efficient Reaction Media for the Synthesis of Pyran Skeleton via Domino Knoevenagel–Hetero–Diels–Alder Reaction with Unactivated Alkynes

The article describes ionic liquids [bmim][NO₃] in the presence of 30% mol CuI as efficient media for the domino Knoevenagel–hetero–Diels–Alder reaction of o-propargyloxy benzaldehydes as unactivated terminal alkynes with some active methylene compounds. Short reaction time, easy workup, good to excellent yields, and mild conditions are advantages of this new media.

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