Advanced Materials Research Vol. 410

Abstract: Lightweight sandwich panels (LWSP) have been used in various sectors of construction and transportation industries. However, due to the cost and complexity of the manufacturing process, their usage in high level sport equipment has been somewhat neglected. This study investigates the feasibility of using a wood veneer sandwich panel to construct the playing surface of a table tennis table. The effects of material parameters, such as the face sheet thickness, core configuration, core thickness and surface coating, on the dynamic friction coefficient and coefficient of restitution, which ultimately dictate the speed, bounce and spin of the ball, will be examined. All results from characterisation of the LWSP table using the International Table Tennis Federation (ITTF) standards will be compared with those from commercially available tables. The material parameters identified to yield the most consistent and favourable characteristics for a table tennis game will be applied for construction of a full size demonstration table.

Abstract: This research work concerns a study on the effect of donor-acceptor graft copolymer, namely poly-p-phenylene vinylene grafted with polystyrene fullerene (PPV-g-PSFu), on morphology and power conversion efficiency of bulk heterojunction solar cells (BHJ) based on P3HT/C₆₀. The aim of this work is to investigate the effect of the graft copolymers content (10, 20 and 40 pph) on morphology and efficiency of the solar cells. The copolymer was mixed with P3HT and C₆₀, by using a solution blending technique. The blend film was fabricated by using a spin coating technique. Power conversion efficiency of the cells was determined by using current density-voltage (J-V) measurements. From the results, it was found that power conversion efficiency (PCE) of various BHJ cells increased from 0.07 x10^-4 % to 1.45 x10^-4 % after the copolymer (20 pph) was added. The above change was discussed in the light of some changes in morphology of the P3HT/C₆₀ blend. Atomic force micrographs (AFM) the various blends showed that, by adding the graft copolymer, the domain size decreased and finer dispersed particle morphology was obtained.

Abstract: A compact flow-through plate silencer is constructed for low frequency noise control by using new reinforced composite plates. The concept comes from the previous theoretical study [1] that in a duct, a clamped supported plate covered with a rigid cavites. The structural property of the very light plate with high bending stiffness is very crucial element in such plate silencer. In this study, an approach to fabricate new reinforced composite panel with light weight and high bending stiffness is developed in order to realize the function of this plate silencer practically. The performance of two plate silencer with the stopband from 229 to 618Hz in which the transmission loss is higher than 10 dB over the whole frequency band can be achieved.

Abstract: Polyvinylidene Fluoride (PVDF) Is Not Inherently Piezoelectric however Non-Piezoelectric α-Crystal Form of the Polymer Can Be Transform to Piezoelectric β-Crystal Form by Application of High Drawing Ratio, Heat and High DC Voltage. in this Work, some Mechanical Tests, such as Linear Density, Tenacity, Elongation%, Were Carried Out to Comparatively Investigate both Poled and Unpoled PVDF Filaments which Were Produced via a Continuous Process in a Customized Melt Extruder. the Voltage Responses of Poled and Unpoled Filaments Were Also Investigated under a Standard Impact Test Ring. These Filaments Were then Studied under Semi Electron Microscopy (SEM) for their Micro Structural Analysis.

Abstract: In this current study, spandex fiber with high elasticity and high recovery ratio were added into shape memory epoxy resin. Compared with pure shape memory resin, the Young’s modulus increases by 28.2%, tensile stress by 49.7% and fracture strain by 16.4% in samples with 20 vol% spandex fiber, while recover time reduces by 36s in samples with 40 vol% spandex fiber.

Abstract: The aim of this paper is to study the influence of frequency in pulse electrodeposition, on the current efficiency, Ni content and surface morphology of deposits from a novel cyanide-citrate electrolyte with 20 mM gold as KAu (CN)₂ and 7 mM NiSO₄, with the aim of design of experiment by respond surface method (RSM). Frequency was in the range of 1-200 Hz in constant average current density, temperature, and duty cycle of 7 mA/cm², 59 ^◦C and 55% respectively. Composition of the deposits was determined by atomic absorption spectroscopy (AAS). Additionally, deposits were characterized by scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDS). It was shown that from main effect plots, decreasing the level of frequency to 50 Hz resulted in an increase in Ni content of the deposits up to 1.5 %. Additionally, by increasing frequency up to 150 Hz, current efficiency increased to 60%. Besides, by decreasing frequency, grain size decreased. It was also shown that duty cycle and frequency have interaction effect on cathode efficiency. Furthermore, by using cyclic voltammetry techniques, Au-Ni electrodeposition from cyanide-citrate electrolyte has been scrutinized and categorized as a diffusion-control system.

Abstract: In this work, pyrithione was modified chemically and resulted in a new molecule of bis (2-(pyridine-N-oxide--2-ylthio) ethyl) amine (abbreviated as BEPA). The suspension of the nanoparticles of the zinc (II) and copper (II) complexes with BEPA were fabricated.

Abstract: Electrospinning is a popular technique for producing micro-or nanofibers for diverse applications including filtration, catalysis, sensors, cosmetics, wound dressing and tissue engineering. In some applications such as controlled drug/biomolecule delivery, core-shell structured nanofibers are desired. There are two major electrospinning processes for making core-shell structured fibers: emulsion electrospinning and coaxial electrospinning. In this study, the formation of core-shell structured fibers of poly (L-lactic acid) (PLLA) through emulsion electrospinning was investigated. To study the electrospinability of emulsions based on PLLA solutions, two solvents, pure chloroform and mixed solvent of chloroform and N,N-dimethylformamide, were used separately for making PLLA solutions. In the study of the formation of controlled release systems for biomolecules, bovine serum albumin, a model protein, was dissolved in de-ionized water to make the water phase in emulsions. In emulsion electrospinning, parameters such as applied voltage, working distance and feeding rate, were systematically investigated. The morphology, diameter and core-shell structure of emulsion electrospun fibers was studied using electron microscopies.

Abstract: Electrospinning is investigated by many groups around the world for constructing fibrous tissue engineering scaffolds. Incorporating biomolecules such as growth factors in fibers is becoming common for enhancing the biological performance of electrospun scaffolds. However, biomolecules may lose bioactivity if they are exposed to organic solvent during electrospinning. In emulsion electrospinning, an aqueous biomolecule solution is emulsified and water-in-oil emulsions are then electrospun into core-shell structured fibers, with biomolecules being contained in the core of fibers, which helps to avoid biomolecule-solvent contact and also reduce the initial burst release. In this investigation, for a comparative study, poly (L-lactic acid) was made into solid and core-shell structured fibers via conventional electrospinning and emulsion electrospinning, respectively. The two electrospinning techniques and resultant fibers were compared in terms of processing parameters (polymer concentration, applied voltage, working distance, etc.) and fiber characteristics (morphology, diameter, structure, etc.). Solvent properties such as conductivity and volatility affected fiber morphology and diameter. The polymer concentration range usable for emulsion electrospinning was narrower than that for conventional electrospinning owing to changes in viscosity.