Fabrication of 80 mm diameter-sized solid oxide fuel cells using a water-based NiO–YSZ slurry

Solid oxide fuel cells (SOFCs) are very attractive for their high energy conversion efficiency and low emissions. Generally, a supported layer of SOFCs is fabricated by tape casting, using an organic solvent. Recently, a slurry based on water instead of an organic solvent has been sought in order to avoid environmental pollution. In this study, the anode of SOFCs was fabricated by aqueous tape casting, and the electrolyte and the cathode were deposited by screen printing. The I–V characteristics of the cell thus obtained were evaluated. As a result, an 80 mm diameter-sized cell with a power density of 0.33 W/cm² at 800 °C was successfully fabricated by controlling sintering conditions.     

Laser brazing of a dissimilar joint of austenitic stainless steel and pure copper

In many industries, there are applications that require the joining of stainless steel and copper components; therefore, the welding of dissimilar stainless steel/copper joints is a common process. For this investigation, the optimal brazing conditions and suitable filler metals for laser brazing of stainless steel/copper lap joints were studied. Tensile shear force increases with increases in the laser spot diameter or in the laser irradiation angle, which is associated with increased bonding width; however, as bonding width approaches 2 mm, tensile shear force reaches a saturated value due to fracturing at the HAZ of the Cu base plate. In order to obtain joints with high tensile shear strength, laser brazing was optimized by using Cu–Si-based filler metal under the following conditions: laser power, 4 kW; spot diameter, 3 mm; laser irradiation angle, 80°; irradiation position shift, 0.6 mm; brazing speed, 0.30 m/min; and filler metal feed speed, 0.30 min. Concerning filler metals, it was found that the Ni–Cu type showed relatively large tensile shear force even at high welding speeds in comparison with those of the Cu–Si, Cu, Cu–Ni, Ni–Cu and Ni types, respectively.     

A study on physical and mechanical properties for soft to firm clays in Yangon area – Properties of clays deposit at the sedimentary basins in Myanmar

Recently, a great deal of foreign investment has been entered into construction of the social infrastructure of Myanmar. Many construction projects are therefore on-going, and these are especially planned in the Yangon area. While these construction booms are increasing, existing studies on the geotechnical problems in the Yangon area such as problematic soils like soft clays are limited at present. Information on soil properties has also not been shared and has been confined to individual projects. In this paper, the boring and laboratory tests carried out in the Yangon area are selected and focused upon among the tests carried out in Myanmar. Laboratory test results for clay deposits in the Yangon area are analyzed and the differences in soil properties between different sedimentary basins and sub-areas divided by the Tertiary sediment ridge that runs from north to south at the center of Yangon are clarified together with a comparison to the clays found in other countries, which have been previously investigated.     

Aerosol Particle Collection Efficiency of Holey Carbon Film-Coated TEM Grids

A simple sampling method to collect aerosol particles for transmission electron microscope (TEM) analysis was developed by R’mili and others in 2013. The method involves passing air through a holey carbon film-coated copper mesh TEM grid (holey carbon grid) and sampling particles by filtration. In this study, we proposed a modified calculation method to represent the collection efficiencies of holey carbon grids, taking into consideration the porosity of the copper mesh. We then evaluated the particle collection efficiencies of holey carbon grids both theoretically and experimentally. We tested the collection efficiency of two types of holey carbon grids, with nominal pore sizes of 1.2 and 0.6 μm, using particles of monodispersed polystyrene latex (PSL) and potassium chloride. The overall collection efficiency of each grid (E_grid) was determined by the downstream/upstream concentration ratio measured by condensation particle counters (CPCs). In addition, for PSL particles, the collection efficiency of the holey carbon film (E_film) was determined by the ratio of the number of particles on the film (counted on a scanning electron microscope) to the number of inflow particles (counted by a CPC). We compared model calculations against the experimental results obtained in this study and those reported by R’mili and others in 2013. These data showed that the calculated E_grid values were in reasonably good agreement with the experimental E_grid values. However, although the model calculation indicated that E_film ≈ E_grid, there was an inconsistency between the experimental E_film and E_grid, which requires further investigation in order to determine its cause.

Copyright 2014 American Association for Aerosol Research     

Network copolyesters from benzenepolycarboxylic acids and 1,6-hexanediol

Network copolyesters were prepared from trimesic (Y), pyromellitic (X) or mellitic (Y_H) acids and 1,6-hexanediol (6G). Prepolymers prepared by meltpolycondensation were cast from dimethylformamide solution and postpolymerized at 260°C for 6h to form a network. The resultant films were transparent, flexible and insoluble in any organic solvents. Degree of reaction estimated from the infrared absorbance of ester and methylene groups was almost the same for all films, 94–96%. X-ray diffraction intensity curves and densities showed that the ordering of networks was decreased by the copolymerization, which was remarkable for 6G–X/Y_H copolymer films and was consistent with the higher decreases of heat-distortion temperature for these copolymer films. The copolymerization also caused decrease of thermal stability, tensile properties and alkali resistance and increase of dye absorption.     

Condensation of organic binary mixtures flowing horizontally in a horizontal tube bundle

Both heat and mass transfer in the gas phase and heat transfer in the liquid phase are examined experimentally for film condensation of organic binary mixtures such as ethanol-water and methanol-water. Experimental results on the average heat flux, vapor-liquid interface temperature and liquid-phase Nusselt number are compared with analytical solutions based on stagnant film theory and heat-transfer relationships for film condensation from a pure vapor. Experimental heat transfer results agree well with the analytical solutions, except that the experimental liquid-phase Nusselt numbers under conditions of low mass fraction of water are considerably higher than predicted by the analytical solutions. This high value of the liquid-phase Nusselt number is considered to be caused by dropwise condensation in the liquid phase. However, its effect on the tube bundle is not so remarkable compared with that in gravity-controlled condensation on a vertical surface. This is considered to be caused by the condensate inundation effect. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(6): 342–361, 1996     

Serum Amyloid A3 Promoter-Driven Luciferase Activity Enables Visualization of Diabetic Kidney Disease

The early detection of diabetic nephropathy (DN) in mice is necessary for the development of drugs and functional foods. The purpose of this study was to identify genes that are significantly upregulated in the early stage of DN progression and develop a novel model to non-invasively monitor disease progression within living animals using in vivo imaging technology. Streptozotocin (STZ) treatment has been widely used as a DN model; however, it also exhibits direct cytotoxicity to the kidneys. As it is important to distinguish between DN-related and STZ-induced nephropathy, in this study, we compared renal responses induced by the diabetic milieu with two types of STZ models: multiple low-dose STZ injections with a high-fat diet and two moderate-dose STZ injections to induce DN. We found 221 genes whose expression was significantly altered during DN development in both models and identified serum amyloid A3 (Saa3) as a candidate gene. Next, we applied the Saa3 promoter-driven luciferase reporter (Saa3-promoter luc mice) to these two STZ models and performed in vivo bioluminescent imaging to monitor the progression of renal pathology. In this study, to further exclude the possibility that the in vivo bioluminescence signal is related to renal cytotoxicity by STZ treatment, we injected insulin into Saa3-promoter luc mice and showed that insulin treatment could downregulate renal inflammatory responses with a decreased signal intensity of in vivo bioluminescence imaging. These results strongly suggest that Saa3 promoter activity is a potent non-invasive indicator that can be used to monitor DN progression and explore therapeutic agents and functional foods.     

Immunomodulatory Properties and Osteogenic Activity of Polyetheretherketone Coated with Titanate Nanonetwork Structures

Polyetheretherketone (PEEK) is a potential substitute for conventional metallic biomedical implants owing to its superior mechanical and chemical properties, as well as biocompatibility. However, its inherent bio-inertness and poor osseointegration limit its use in clinical applications. Herein, thin titanium films were deposited on the PEEK substrate by plasma sputtering, and porous nanonetwork structures were incorporated on the PEEK surface by alkali treatment (PEEK-TNS). Changes in the physical and chemical characteristics of the PEEK surface were analyzed to establish the interactions with cell behaviors. The osteoimmunomodulatory properties were evaluated using macrophage cells and osteoblast lineage cells. The functionalized nanostructured surface of PEEK-TNS effectively promoted initial cell adhesion and proliferation, suppressed inflammatory responses, and induced macrophages to anti-inflammatory M2 polarization. Compared with PEEK, PEEK-TNS provided a more beneficial osteoimmune environment, including increased levels of osteogenic, angiogenic, and fibrogenic gene expression, and balanced osteoclast activities. Furthermore, the crosstalk between macrophages and osteoblast cells showed that PEEK-TNS could provide favorable osteoimmunodulatory environment for bone regeneration. PEEK-TNS exhibited high osteogenic activity, as indicated by alkaline phosphatase activity, osteogenic factor production, and the osteogenesis/osteoclastogenesis-related gene expression of osteoblasts. The study establishes that the fabrication of titanate nanonetwork structures on PEEK surfaces could extract an adequate immune response and favorable osteogenesis for functional bone regeneration. Furthermore, it indicates the potential of PEEK-TNS in implant applications.     

Determination of residual avoparcin in chicken muscle by HPLC with ultraviolet and amperometric detection

An analytical method was developed for determination of residual avoparcin in chicken muscle by measuring alpha- and beta-avoparcin, major components of the pharmaceutical preparation avoparcin, using HPLC with UV and amperometric detectors. The analytical HPLC was run on a Cosmosil 5C18-AR column (4.6 mm x 25 cm) with a gradient formed from A: 2.5% acetic acid, 0.01 mol/L sodium heptane sulfonic acid-acetonitrile (88.5:11.5) (pH 4.0) and B: 2.5% acetic acid-acetonitrile (10:90), using UV and amperometric detection (AMD) with glassy-carbon electrode (+900 mV). Avoparcin was extracted from chicken muscle by homogenization with methanol-0.2 mol/L sulfuric acid (6:4) followed by centrifugation after pH adjustment to 4 with 1 mol/L sodium hydroxide. The supernatant was evaporated to dryness, and the residue was dissolved in water. The aqueous layer was adjusted to pH 4 by adding 1 mol/L sodium hydroxide. Then it was purified on a Sep-Pak tC18 plus ENV cartridge. The cartridge was washed with water, and retained substances were eluted with 50% methanol. The eluate was evaporated to dryness under reduced pressure. The residue was dissolved in water and determined by HPLC. Recoveries of avoparcin spiked in chicken muscle were 73.1-88.1% at levels of 2-10 micrograms/g. The detection limits were 0.5 microgram/g (UV) and 0.2 microgram/g (AMD).     

Preparation of sharp-melting hard palm midfraction and its use as hard butter in chocolate

Preparation of hard palm midfractions (PMF) and its use as a cocoa butter equivalent ingredient were studied. Hard PMF is obtained by multistep fractionation of palm oil involving dry fractionation (DF) and/or solvent fractionation (SF), usually using hexane or acetone. From our experience, in acetone, a polar solvent, symmetrical 1,3-disaturated triacylglycerols tend to selectively crystallize more than nonsymmetrical 1,2- or 2,3-disaturated triacylglycerols, making it suitable for obtaining the solid midfraction. Unfortunately, triacylglycerols are very soluble in hexane, and temperatures at least 15 degrees lower than those required for acetone must be used for equivalent crystal yields. On the other hand, DF is a less expensive and safer process. Thus, multistep fractionation combining DF and SF using acetone was developed to achieve sufficient removal of high-melting components, and further enrichment of 1,3-dipalmitoyl-2-oleoylglycerol and the hard PMF was obtained by triple-step fractionation of palm olein or double-step fractionation of soft PMF. Compared to conventional hard PMF, this hard PMF had a steeper melting curve and better snapping and sharp-melting qualities when used in chocolate. Heat resistance of the hard PMF chocolate was similar to the conventional hard PMF chocolate, and its bloom resistance could be improved by adding polyglycerol fatty acid esters.