Electrochemical study of indoor atmospheric corrosion layers formed on ancient iron artefacts

Several indoor atmospheric corrosion layers (0-800 years old) were selected from different localisations in France. Each sample was scrapped from its iron substrate. The resulting powder was mixed with graphite in appropriate proportions and the mixture was pressed onto a stainless steel grid to constitute a composite electrode. The electrochemical responses of the different samples were recorded under galvanostatic regulation, in a near-neutral pH-buffered NaCl solution at 25 °C. The E-t reduction curves allowed the determination of two characteristic parameters, E_τ/2, the potential value obtained at half the transition time, and Q_τ, the coulombic charge obtained at the end of the reduction. The diminution of E_τ/2 and Q_τ with the age of the corrosion layer showed that the “reduction reactivity” decreases with time, suggesting a progressive stabilisation of the corrosion layer.In a second part of the work, we synthesised several common ferric or ferrous/ferric products (goethite, lepidocrocite, magnetite, maghemite, ferrihydrite) and compared their reduction responses (product alone or mixture of 2 or 3 products) to those of corrosion samples.     

Synthesis of monodisperse nickel‐coated polymer particles by electroless plating method utilizing functional polymeric ligands

In the electroless plating process, to omit a sensitizing process with SnCl₂, we utilized amino‐functional groups on polymer particles. At first, highly monodisperse functional polymer particles could be prepared by a two‐step seeded polymerization of styrene, divinylbenzene, and glycidyl methacrylate. Then, surface epoxy‐functional groups were converted to amino‐functional groups by treating the particles with a diamine. By using these surface amino functionalities, we tried to prepare uniformly metal‐coated monodisperse polymer particles by electroless plating method. The constituents of an electroless nickel solution bath are nickel salt, a reducing agent, suitable complexing agents, and stabilizers. And the metal thickness was simply controlled by changing the loading amount of substrate polymer particles. Morphological observation of nickel‐plated polymer particles was conducted by using optical microscopy, scanning electron microscopy, and transmission electron microscopy. The structural composition of plated nickel was also investigated. Most of all, the function and the efficiency of the amino‐functional group of polymer particles as a polymeric ligand for metal binding was elucidated. From all observations, it was evident that in the electroless metal plating process without any sensitization step, the deposition of metal clusters on substrate particles is largely dependent upon the particle surface functionality. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3801–3808, 2006     

Preparation and photophysical properties of organic fluorescent polymers and their nanoparticles

New classes of stable organic florescent polymer nanoparticles were prepared from the corresponding tetrahydrofuran (THF) solutions, upon slow evaporation of solvent under a mild vacuum. Uniform spherical nanospheres having mean diameter of ? 500–700 nm, showed enhanced fluorescence emission in solution, but it diminished when it is destroyed using an organic base. These end‐capped fluorescent polymers are highly stabilized in the excited states at higher concentration in solution, leads no more intra‐ and intermolecular interactions among the excited molecules, because of the absence of free functional groups. The significant enhancement in fluorescence emission was attributed to the high level of molecular stacking in the fluorescent nanoparticles, when compared with micron‐sized isolated powder sample. In addition, these fluorescent polymers exhibited significant thermal properties, along with better solubility in most of common organic solvents for their future application. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5344–5350, 2006     

Hexafunctional poly(propylene glycol) based hydrogels for the removal of heavy metal ions

Two types of degradable poly(propylene glycol) (PPG) hydrogels that are suitable for the absorption of heavy metals have been presented. The PPG‐O‐P(O)Cl₂ fragments obtained by treating hexafunctional PPG with phosphorous oxychloride (POCl₃) react with 1,3‐propanediamine (PDA; Gel‐1 ) or PDA together with 1,2‐ethanedithiol ( Gel‐2 ), to yield cross‐linked and water‐swellable hydrogels in a one‐pot method. This protocol for the fabrication of PPG hydrogels exhibits promising advantages over prior methods including a short reaction time, mass‐production, easy separation, and high yield. A series of heavy metal ions were employed to test the adsorptive properties of the hydrogels. Gel‐2 shows better adsorption capacity than Gel‐1 for all the metal ions and the metal ions adsorption efficiency of the two types of hydrogels is in the order of Fe(III) > Pb(II) > Cd(II) > Zn(II) > Cu(II) > Ni(II) > Co(II) > Hg(II). The amounts of metal ions adsorbed increases with metal ion concentration and hydrogel dosage, but decreases with temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40610.     

Interactive robust optimal design of plastic injection products with minimum weldlines

A new robust optimal design methodology has been developed and applied to the design of plastic injection molding products. Taguchi’s robust design method and an optimal design search algorithm are integrated with a commercial CAE simulation tool. A direct search-based optimization procedure is implemented with the considerations of process variations as well as uncontrollable noise variables. The Interactive Design Space Reduction Method (IDSRM) based on orthogonal arrays for design of experiments is developed as a general optimization tool. Using the system, designers can interactively adjust the design space during the searching process for the optimal solution based on the outcomes of the experiments. The developed methodology is applied to an industrial application: a molding process design of an automobile front bumper to minimize the weldline, a form defect of plastic parts. Compared with the initial design solution, the optimized design aided by the proposed methodology shows a more efficient and better result in terms of design robustness against process variations.     

Effect of changes in ambient conditions on the homogeneous combustion characteristics and flammability limits of biodiesel fuel combustion using surrogate fuel coupled with a combustion mechanism

Journal of Mechanical Science and Technology - The purpose of this study was to analyze numerically the homogeneous combustion characteristics of biodiesel and diesel fuels and to investigate the...     

Multibody dynamic analysis of a duplicate bimodal tram

This study aimed to dynamically analyze a simulated bimodal tram by determining the motion equations for computer-aided analysis with Newton-Euler equations of motion, which algebraically represent motion. We utilized the multi-body dynamics analysis program, MSC.Adams, to evaluate the equations of motion, running stability, curving performance, and ride comfort of the simulated bimodal tram in comparison with single fleet and double fleet trams. For the double fleet tram, the characteristic equation was deduced to control the all-wheel steering mechanism by independently moving all the wheels characterizing an articulated vehicle. Our study aimed to design a double fleet bimodal tram. We confirmed that domestic and international standards were satisfied via the design and analysis of the simulation. Steering control equations are the significant preliminary data for coupling device research and development for double fleet bimodal trams.     

Electron beam lithography-assisted fabrication of Au nano-dot array as a substrate of a correlated AFM and confocal Raman spectroscopy

This paper documents a study of an Au nano-dot array that was fabricated by electron beam lithography on a glass wafer. The patterns that had features of 100nm dots in diameter with a 2-mum pitch comprised a total area of 200x200mum(2). The dot-shaped Cr underlayer was open to the air after developing Poly(methyl methacrylate) (PMMA). When dipped into the Cr etchant, the exposed Cr layer was eliminated from the glass wafer in a short period of time. In order to ultimately fabricate the Ti/Au dot arrays, Ti and Au were deposited onto the arrays with a thickness of 2 and 40nm, respectively. The lift-off procedure was carried out in the Cr etchant using sonication in order to completely remove the residual Cr/PMMA layer. The fabricated Au nano-dot array was then immersed in an Ag enhancing solution and then into an ethanol solution containing (N-(6-(Biotinamido)hexyl)-3'-(2'-pyridyldithio)-propionamide (Biotin-HPDP). The substrate was analyzed using a correlated atomic force microscopy (AFM) and confocal Raman spectroscopy. Through this procedure, position-dependent surface-enhanced Raman spectroscopy (SERS) signals could be obtained.     

Development of a Web-based RCM system for the driverless Rubber-Tired K-AGT system

The Korean Railroad Research Institute (KRRI) developed the rubber-tired AGT system (Model: K-AGT) between 1999 and 2005. The K-AGT is a light rail transit system does not require a driver and generally operates on an elevated railroad for transporting passengers. Accidents caused by driverless vehicles can severely affect social confidence, safety and economy. Therefore, it is very important to minimize the occurrences of such faults, and to accurately perform detailed maintenance tasks and thoroughly investigate the cause of any repeated failures. This research develops the web-based reliability centered maintenance (RCM) system for the K-AGT train system. The framework of the RCM system is based on performing a failure mode and effects analyses (FMEA) procedure on all the sub-systems in the K-AGT system. Out of the devices that have a low reliability, the high failure ranked devices are included high on the list for performing the overall maintenance plans. Through registration of historical failure data and the reliability indexes, the results of the FMEA can be updated. Such a process is repeated continuously and can achieve very accurate predictions for device operational lifetimes and failure rates. Also, the RCM system is designed so that workers can refer to the expert system for the latest procedures to perform the required diagnosis and repair of any failure. The overall RCM system consists of a failure/task management system, a preventive maintenance system, an expert system, a material management system, and an approval system. This research describes the development of the preventive maintenance system and the expert system that have been produced because these are the main functions for the RCM system. This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim Myung-Won Suh is a Professor of Mechanical Engineering. During 1986–1988, he worked for Ford motor company as researcher. From 1989–1995, he worked in technical center of KIA motors. He took a BS degree in Mechanical Engineering from Seoul National University and an MS degree in Mechanical Engineering from KAIST, South Korea. He obtained his Doctorate at the University of Michigan, USA, in 1989. His research areas include structure and system optimization, advanced safety vehicle and reliability analysis & optimization. Chul-Ho Bae is a PhD candidate at Sungkyunkwan University in Suwon, South Korea. He accomplished fellowship work as researcher at Mississippi State University, USA, in 2003 and 2005. He worked in Institute of Advanced Machi-nery and Technology (IMAT) as a Research Assistant in 2004. He was a part time Lecturer in computer aided Mechanical Engineering of Ansan College of Technology, Suwon Science College, and Osan College during 2004–2005. He took a BS Degree in Mechanical Design and an MS Degree in Mechanical Engineering from the Sungkyunkwan University. His research interests include computer aided engineering, reliability engineering, and optimization.