Applied Mechanics and Materials Vol. 372

Abstract: This study investigates the effect of Sodium Chloride (NaCl) coagulant medium with different concentration to produce Polysulfone (PSf) ultrafiltration (UF) asymmetric membrane. The polymer membrane prepared by a phase inversion method using Polysulfone (PSf) as a base polymer, Polyethylene glycol (PEG) 400MW as copolymer additive, N-methyl-2-pyrrolidone (NMP) as solvent and NaCl coagulant medium with different concentration as nonsolvent. In this work, the concentration of immersion medium for membrane phase immersion process prepared based on different coagulation concentration medium NaCl was modified repeatedly in the range of 1-5%. These membrane performance were analyzed via pure water permeation and solute rejection of humic acid. Based on these results, the membrane immersed in 4% concentration of NaCl coagulant medium showed the highest pure water permeation (235.69 l.m^-2. h^-1) and solute rejection of humic acid which is up to 98%.

Abstract: In the present work, polysulfone (PSf) ultrafiltration membranes were prepared by solution casting. The effects of rice husk silica (RHS) on the surface properties of the PSf/Polyethylene glycol (PEG) membrane were observed and investigated. Characterizations were conducted to determine the membrane cross-section area and RHS distribution. The structure of RHS and morphology of membrane were analyzed by using X-ray diffractometer (XRD) and scanning electron microscope (SEM). XRD pattern showed that the amorphous silica was produced from rice husk ash (RHA). The analysis of SEM indicates that the addition of RHS obviously changed the microstructure of the membrane especially at top layer and sub layer.

Abstract: Marcoporous silica hollow microspheres were prepared by poly (acrylic acid)@poly (ethyleneglycol dimethacrylate-co-4-vinylpyridine) (PAA@P(EGDMA-co-VPy)) composite particles with raspberry-like structure as the template. P(EGDMA-co-VPy) and PAA microspheres were prepared by distillation precipitation polymerization respectively. The raspberry-like organic composite polymer particles were obtained through the self-assembly of PAA microspheres on P(EGDMA-co-VPy) microspheres. Then, Silica layer was coated on the composite particles with Stöber method in an alkaline environment. The marcoporous silica hollow microspheres were received after the calcination to remove the organic template. The diameter of the marcoporous silica hollow microspheres, hollow inner core and the pore size of silica layer was about 2.0 μm, 1.5 μm and 20-130 nm, respectively.

Abstract: The purpose of this research is the development of new design method for integrating the optimum strength evaluation and the product design which can make the best use of material's characteristics obtained by the experiment and the analysis. Further we do design using high-strength composite material with this developed concept which is different from conventional design. First, to establish this design method of high-strength materials, we examined these materials characteristics and manufacturing methods and the commercialized products. As this research target material, we focus the fiber reinforced materials such as composite with carbon fiber, glass fiber and aramid fiber. Above all, we marked the carbon fiber which has the high specific tensile strength, wear resistance, heat conductivity and conductance. Here, we introduce the fundamental design concept which makes the best use of the design with enough strength.

Abstract: Fe_81-xNi_xGa₁₉(with x ranging from 0-25 at.% Ni) ribbons were made by melt spinning method. We have studied the structural (phases, texturing, and lattice parameter), magnetic (saturation magnetization and saturation magnetostriction) properties of these ribbons. The main results are as follows: (i) For x≤10, all the ribbons are A₂ single phase; for x=15, the ribbon is of A₂+L1₂+DO₃+E2₁ phase; for x=20, the ribbon is of A₂+L1₂+DO₃+B₂ phase; for x=25, only A₂ and L1₂ phases exist. (ii) For x=5 and 15, an obvious (211) texture was detected, whereas other ribbons are (110) textured, no (100) texture was tested. (iii) (110) texture in our ribbons brought low saturation magnetic field (Hs) and high saturation magnetostrction (λs). (iv) E2₁ phase played a positive role in the magnetostricion of FeNiGa ribbons.

Abstract: This paper presents how a single rising bubble experiment in the Hallimond Tube (HT) can be predicted using a computational fluid dynamics model (CFD). The study is emphasized on the effect of CFD Mesh to the pressure coefficient and axial velocity around the bubble. A rigid sphere with the radius of 0.00575 m using flow velocity of 0.0067 m/s was considered in this study. Experimental and simulated data obtained by other researchers in the similar study were used to validate the simulation results from the computational fluid dynamics model.

Abstract: The solder/substrate reactions, for Sn-1.0Ag-0.5Cu, Sn-1.0Ag-0.5Cu-0.05Ni and Sn-1.0Ag-0.5Cu-0.05Ni-0.02B, were evaluated in what concerns the melting temperature, microhardness, morphology of the solder and chemical composition of the interface layer. The phases formed at the interface between the Cu Substrate and a molten lead-free solder were studied with different stage times. The evaluation of their chemical compositions were performed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS).

Abstract: In this article, studies were conducted to evaluate the densification of W-Cu sintered compacts produced using two methods; liquid phase sintering (LPS) and combination of liquid phase sintering and liquid infiltration technique (LPS+LI) named Cu-melt infiltration (Cu-MI). Low concentration of nickel (1wt.%) was used to activate the sintering process in both methods. Isothermal sintering was carried out in alumina tube furnace at temperatures of 1150°C for 2 hr. under H₂/Ar. as protective gas. The infiltration (Cu-MI) method proved to be effective in the densification, microstructure and hardness enhancement of the 80W-Cu compact as opposed to the other conventionally liquid phase sintered compacts. The relative densities of 80W-Cu-1Ni composites prepared by using insert method (Cu-melt infiltration) achieved 96.22% of theoretical density.

Abstract: The reflective properties and illumination uniformity of the polymer can be improved effectively with microstructure on the surface and scattering particles with high refractive index inside. The paper is based on the early research of the author. The reflector cup is processed by injection molding using the polymer of high reflective properties, which can achieve high efficiency of the light energy utilization and the uniform emergent ray.