Plasma deposition of a silicone-like layer for the corrosion protection of magnesium

Magnesium (Mg) and its alloys are widely used for biodegradable implant materials due to their degradability and mechanical properties similar to bone. However, the high corrosion rate and release of hydrogen gas hinder its clinical application. In this study, plasma-polymerization was used to deposit the hexamethyldisiloxane (HMDSO) polymeric films on Mg surface using low temperature radio frequency discharge plasma. The chemical and physical properties of the HMDSO films were characterized by contact angle measurements, field emission scanning electron microscope, and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Contact angle results show that the contact angle and the plasma discharge powers are strongly correlated. ATR-FTIR results indicate that plasma-polymerized HMDSO films have a chemical structure close to polydimethylsiloxane (PDMS). The weight loss test and electrochemical impedance spectroscopy were performed immersion in 0.9% NaCl solution in order to investigate corrosion protective properties of the coating layer. It was found that HMDSO plasma-polymerized coating layer showed good anti-corrosion properties than that of untreated samples. These results that the polymeric films coated on Mg may be potentially applied for clinical use.     

Dynamic modeling and analysis of a shell-and-tube type gas-to-gas membrane humidifier for PEM fuel cell applications

A gas-to-gas humidifier using membranes is the preferred technology for external humidification of fuel cell reactant gases in mobile applications because no extra power supply is required and there are no moving parts. In particular, a shell and tube structure is compact, which allows its easier integration in a fuel cell vehicle.

This paper proposes a mathematical model for the humidifier using the principles of thermodynamics, including analysis of heat and mass transfer and of static and dynamic behaviors. Firstly, the heat and mass transfer behavior was simulated and the results compared with the experimental data. Secondly, the model was used to investigate the sensitivity of the geometric parameters and the effects of various operating conditions on performance. Finally, step responses of the humidifier at various flow rates were analyzed.     

Coolant controls of a PEM fuel cell system

When operating the polymer electrolyte membrane (PEM) fuel cell stack, temperatures in the stack continuously change as the load current varies. The temperature directly affects the rate of chemical reactions and transport of water and reactants. Elevated temperature increases the mobility of water vapor, which reduces the ohmic over-potential in the membrane and eases removal of water produced. Adversely, the high temperature might impose thermal stress on the membrane and cathode catalyst and cause degradation. Conversely, excessive supply of coolants lowers the temperature in the stack and reduces the rate of the chemical reactions and water activity. Corresponding parasitic power dissipated at the electrical coolant pump increases and overall efficiency of the power system drops.     

Fabrication of laser-annealed poly-TFT by forming aSi1-xGex thermal barrier

Germanium is ion-implanted deeply into the bottom of a Si film before excimer laser annealing begins. During the solidification step, the implanted Ges form a high thermal resistive Si_1-xGe_x alloy, which reduces the thermal extraction rate of laser energy and the grain growth rate. Laterally larger but double-stacked grains were achieved with a higher Ge implant dose and a slower grain growth. The performance of fabricated poly-TFTs has been enhanced with a Ge 5×10¹⁵/cm² at 80 keV implant but deteriorated at a higher dose. We attribute this enhancement to a laterally enlarged grain and show that the performance of TFT is deteriorated more dominantly by other Ge-related factors than by surface roughening and Ge-induced defect creation     

Construction of the Asian American Family Conflicts Scale.

This study describes the construction and initial validation of the Asian American Family Conflicts Scale (FCS) with 3 samples of Asian American college students. The scale consists of 10 typical Asian American family conflicts that are rated for likelihood of occurrence (FCS-Likelihood) and seriousness of conflict (FCS-Seriousness). In Study 1, FCS-Likelihood and FCS-Seriousness had sound internal reliability, stability, and construct validity. In Study 2, FCS-Likelihood correlated with socioeconomic and cultural orientation variables. Ethnic, generation, and language differences, as well as the parent–child acculturation gap hypothesis, also were confirmed for FCS-Likelihood. In Study 3, FCS-Likelihood correlated with measures of family cohesion, adaptability, and parent-child communication. Although further validation is necessary, FCS-Likelihood in particular is a potentially useful research and clinical instrument for assessing the quality of Asian American parent–child relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perchlorate adsorption and desorption on activated carbon and anion exchange resin

The mechanisms of perchlorate adsorption on activated carbon (AC) and anion exchange resin (SR-7 resin) were investigated using Raman, FTIR, and zeta potential analyses. Batch adsorption and desorption results demonstrated that the adsorption of perchlorate by AC and SR-7 resin was reversible. The reversibility of perchlorate adsorption by the resin was also proved by column regeneration test. Solution pH significantly affected perchlorate adsorption and the zeta potential of AC, while it did not influence perchlorate adsorption and the zeta potential of resin. Zeta potential measurements showed that perchlorate was adsorbed on the negatively charged AC surface. Raman spectra indicated the adsorption resulted in an obvious position shift of the perchlorate peak, suggesting that perchlorate was associated with functional groups on AC at neutral pH through interactions stronger than electrostatic interaction. The adsorbed perchlorate on the resin exhibited a Raman peak at similar position as the aqueous perchlorate, indicating that perchlorate was adsorbed on the resin through electrostatic attraction between the anion and positively charged surface sites.     

Effects of jupcheong (soaking in syrup) with ginger powder on the lipid oxidation and antioxidant stability of yakgwa (Korean deep-fried confection)

Food Science and Biotechnology - This study evaluated the effect of jupcheong (soaking in syrup) with/without ginger on lipids and antioxidants of yakgwa (Korean deep-fried confection) during...     

Technical report: double-phase technetium-99m-sestamibi parathyroid imaging with an in-field photopenic marker for better mapping

The author introduces a photopenic marker that was used to delineate better anatomic mapping in a double-phase technetium-99m-sestamibi parathyroid imaging. This home-marker was placed on a patient within the imaging field to increase reproducibility of the images: early versus delayed images.     

Investigation of the kinetics of intergranular corrosion in iron

Corrosion experiments on iron were performed in boiling 55% Ca(NO₃)₂ solution (115°C) to elucidate the kinetics of intergranular corrosion (IGC) of iron. After the time-current curve was recorded for the specimen exposed for 30 h to the IGC test solution at 1000 mV_SHE (passive region), the specimen was examined for IGC by optical microscopy. The current-time curves and optical micrographic observations suggested that the kinetics of IGC of iron is based upon the periodic passivation-grain boundary dissolution process. IGC occurs mainly between the first passivation and the second repassivation periods. Average current density during this period can be regarded as a measure of the susceptibility to IGC. The excess dissolved nitrogen or nitride at the grain boundaries does not lead to a definite IGC.