Applied Mechanics and Materials Vols. 719-720

Abstract: Aiming at the problem that temperature filed changes can lead to edge cracks emerge to Al-Si alloy 4004 in the process of hot rolling, in this paper, finite element model of temperature field variations in the process of rolling have been established by the method of finite element numerical simulation. The relationship between temperature field variations and edge crack defects has been analyzed. The results show that temperature field of rolled piece is gradient variations, low in the center and high in the edge, metal accumulation in the edge, leading to stress concentration and forming cracks source, resulting in edge cracks arising in edge of roller piece. Finally, the reliability and accuracy of the numerical simulation method have been verified by hot-rolled tests and tensile tests. All the studies provide ideas for theoretical analysis of temperature variation during hot rolling and have important significance on improve the quality of products.

Abstract: Acetylide and thiourea moieties individually provides a wide range of electronic properties as they possess electronic delocalization in extended rigid π orbital system in their designated structures. In this work, a new derivative of N-([4–aminophenyl] ethynyltoluene)-N’-(1-naphthanoyl) thiourea (ATT) was successfully synthesized and spectroscopically characterized by using FT-IR, NMR, and UV-Vis analysis. In turn, the development of new sensing material thin-film based on ATT has been accomplished by incorporating with polyvinyl chloride (PVC) via dip-coating technique. The difference in absorption behavior using UV-visible spectroscopic analysis was employed to determine the sensitivity of thin-film towards carbon monoxide (CO) gas of 10, 20, and 30 ppm. ATT exhibits high sensitivity towards 30 ppm CO gas with 55% sensitivity. Quantum mechanical calculation via Gaussian 09 shows that ATT has potential van der Waals interaction towards CO with stabilization energy-6.54 kJ/mol and 3.14Ǻ of interaction distance between substrate and analyte. It is proven that ATT as single molecule gives great potential to be explored and used as sensing material application particularly in CO detection.

Abstract: The graft copolymerization of vinylbenzyl chloride (VBC) onto nylon-6 fiber was investigated by the pre-irradiation method using electron beam. The effects of grafting parameters, monomer concentration, absorbed dose and reaction temperature were investigated. The empirical kinetic rate equation dGo/dt=k[M]^0.86*[D]^1.06 was used to describe grafting of VBC onto nylon-6. The overall activation energy for graft copolymerization of VBC was found to be 22.6 kJ/mol. The results revealed that the grafting kinetic was controlled by the amounts of trapped radicals and monomer molecules. Fourier transform infrared (FT-IR) was used to provide evidence for the formation of grafted copolymers.

Abstract: The present work investigated the effect of carboxy methylcellulose (CMC) solid polymer electrolytes doped with ammonium carbonate (AC) prepared from solution cast technique. The CMC-AC solid polymer electrolytes system has been analyzed using EIS to understand its conductivity and dielectric behavior at temperature range of 303 K to 363 K. The highest conductivity achieved at room temperature (303K) is 7.71 x 10^-6 S cm^-1 doped with 7wt.% of AC and all samples follows Arrhenius behaviour. The dielectric constant (ε_r) value was found to be dependent of ionic dopant.

Abstract: Palygorskite/polyacrylamide (PAM) composited thickeners were prepared via in-situ polymerization. To optimize the preparation, the dependence of the viscosity, rheological properties and electrolyte resistance of the composited thickeners on the initiator concentrations, sodium hydroxide concentrations and palygorskite contents was investigated. By measuring their dynamic rheological properties, thickening mechanism of composited thickeners was explored. The composited thickeners showed excellent electrolyte resistance which represented good synergistic effect of inorganic/organic composited thickener.

Abstract: Charcoal derived from Cogongrass (Imperata cylindrica) consisting of cellulose, hemicellulose and lignin were collected for the experiment. The Cogongrass feeding to the continuous pyrolysis reactor at 500°C. When its passing the unit operate system, we can received all yield (liquid, solid and gas) on during pyrolysis, expecially, the solid product (charcoal). In this study, We have emphasized the characteristics and pattern surface and inside of charcoal by using Scanning Electron Microscope (SEM) and Energy Disperssive Scanning (EDS).

Abstract: Polymer electrolytes blends of methylcellulose (MC)/chitosan-ammonium triflate (NH₄CF₃SO₃) plasticized with Ethylene Carbonate (EC) were prepared by solution-casting technique. The effect on electrical property was investigated by impedance spectroscopy. Sample with 45 wt% of EC exhibit the highest room temperature conductivity of 2.16 × 10^-4 Scm^-1. Dielectric data were analyzed for the sample with the highest conductivity.

Abstract: In this investigation, bulk ultra-fine grained and nanocrystalline Al-2 wt.% Fe alloy was produced by mechanical alloying (MA). The powder was mechanically milled in an attritor for 3 hours and yielded an average crystal size of ~63 nm. The consolidation and sintering was performed using a high frequency induction sintering (HFIS) machine at a constant pressure of 50 MPa. The prepared bulk samples were subjected to uniaxial compressive loading over wide range of strain rates for large deformation. To evaluate the effect of sintering conditions and testing temperature on the strain rate sensitivity, strain rate jump experiments were performed at high temperature. The strain rate sensitivity of the processed alloy increased with an increase in temperature. The density of the bulk samples were found to be between 95 to 97%. The average Vickers micro hardness was found to be 132 Hv_0.1.

Abstract: In recent years a number of studies were conducted in order to obtain polymer composites with superior performance when compared to the metallic alloys. However, these new materials must meet a series of rigid project requirements. One way to evaluate the polymer composites is through their transition temperatures, especially the glass transition temperature (Tg). It is possible to evaluate the Tg of a polymeric material through the study of changes in dimensions of a sample as a function of temperature. These measurements can be made on an equipment of thermomechanical analysis (TMA), however, despite great sensitivity, this technique is basically unknown by most users when compared to others such as DSC or DMA. Even with different technical principles of operation, the results show similarity. Thus, this study aims to compare the results of Tg polymer composites obtained via TMA with those obtained from DSC curves in epoxy resin/carbon fiber laminates.

Abstract: Experimental comparative evaluation of cutting properties of edge tools underspecified operating conditions is undesirable, since it takes a lot of time and expenses. The need for development of simulation techniques is clear, and the above techniques can be the basis for the classification of compared edge cutting tools on their most appropriate features and for the selection of the most rational type of such a tool using a technique of nondestructive testing. The analysis of the studies in the field of evaluation of the cutting tool properties by nondestructive testing techniques as well as our own experience of developing similar techniques suggest that such a technique could be developed on the basis of the pendulum scribing technique. Thus, the objective of this study was to develop procedures for the selection of rational parameters of edge cutting tools for specified machining conditions based on simulating a low-cost process.The study was supported by grant No. 9.251.2014/K, project code 251.