Nanostructured polymer blend formed from poly(N-vinylpyrrolidone) and end-functional polystyrene

Phase structures of blends of poly(N-vinylpyrrolidone) (PVP) with SO₃H terminated polystyrene (PSS) were investigated. The PVP-PSS blends were macroscopically homogeneous, although the blends of PVP with polystyrene (PS) showed macroscopic phase separation. The PVP-PSS blends, however, showed two glass transitions indicating existence of two phases. Small-angle X-ray scattering measurements revealed the PVP-PSS blends formed mesomorphically ordered morphologies which change with variation of blend composition. The nano-organized phase separation in the PVP-PSS blends was caused due to hydrogen bonding of the PVP with the terminal SO₃H group of the PSS and repulsive interaction between PVP and main chain of the PSS.     

Alcohol electrooxidation at Pt and Pt–Ru sputtered electrodes under elevated temperature and pressurized conditions

The electrooxidation properties of methanol and 2-propanol, which are both promising candidates for direct alcohol fuel cells (DAFCs), have been studied under elevated temperature and pressurized conditions. Sputter-deposited Pt and Pt–Ru electrodes were well-characterized and utilized for the electrochemical measurement of the alcohol oxidation at 25–100 °C. The Pt electrode prepared at 600 °C had a flat surface, and the Pt–Ru formed an alloy. The electrochemical measurements were carried out in a gas-tight cell under elevated temperature, which accompanies the pressurized condition. This is a representative example of the DAFC rising temperature operation. As a result, at 25 °C, the onset potential of the 2-propanol oxidation is about 400 mV more negative than that of the methanol oxidation, and current density of the 2-propanol oxidation exceeds that of the methanol oxidation. Conversely, at 100 °C, the methanol oxidation current density overcomes that of 2-propanol, and the onset potentials of the two are almost the same. The highest current density for the methanol oxidation is obtained at the Pt:Ru = 50:50 electrode, whereas at the Pt:Ru = 35:65 for the 2-propanol oxidation. A Tafel plot analysis was employed to investigate the reaction mechanism. For the methanol oxidation, the number of electrons transferred during the rate-determining process is estimated to be 1 at 25 °C and 2 at 100 °C. This suggests that the methanol reaction mechanism differs at 25 and 100 °C. In contrast, the rate-determining process of the 2-propanol oxidation at 25 and 100 °C was expected to be 1-electron transfer which accompanies the proton-elimination reaction to produce acetone. Consequently, it is deduced that methanol and 2-propanol have an advantage under the rising temperature and room temperature operation, respectively.     

Antenatal Glucocorticoid Administration Promotes Cardiac Structure and Energy Metabolism Maturation in Preterm Fetuses

Although the rate of preterm birth has increased in recent decades, a number of preterm infants have escaped death due to improvements in perinatal and neonatal care. Antenatal glucocorticoid (GC) therapy has significantly contributed to progression in lung maturation; however, its potential effects on other organs remain controversial. Furthermore, the effects of antenatal GC therapy on the fetal heart show both pros and cons. Translational research in animal models indicates that constant fetal exposure to antenatal GC administration is sufficient for lung maturation. We have established a premature fetal rat model to investigate immature cardiopulmonary functions in the lungs and heart, including the effects of antenatal GC administration. In this review, we explain the mechanisms of antenatal GC actions on the heart in the fetus compared to those in the neonate. Antenatal GCs may contribute to premature heart maturation by accelerating cardiomyocyte proliferation, angiogenesis, energy production, and sarcoplasmic reticulum function. Additionally, this review specifically focuses on fetal heart growth with antenatal GC administration in experimental animal models. Moreover, knowledge regarding antenatal GC administration in experimental animal models can be coupled with that from developmental biology, with the potential for the generation of functional cells and tissues that could be used for regenerative medical purposes in the future.     

Influence of small amount of glass fibers on mechanical properties of discontinuous recycled carbon fiber-reinforced thermoplastics

The effect of residual contamination, such as glass fibers (GFs), on the application of discontinuous recycled carbon fibers (rCFs) is still unclear. In this study, GFs are used to substitute rCF at volume fractions (Vfs) of 0%, 1%, 2%, and 5% in carbon fiber paper-reinforced thermoplastics fabricated through a papermaking process. After an investigation with the three-point bending tests, the flexural modulus will not decrease when the GF content increased. Unlike the flexural modulus, the flexural strength decreased with an increase in the GF volume. In order to illustrate the effect of small amount of GF on flexural modulus, a modified rule of mixture (ROM) is used to derive a coefficient, Factor c₁, depicting the effect caused by discontinuous and randomly distributed reinforcement fibers. Furthermore, modified Halpin–Tsai model with Factor c₁ illustrated that the experiment results of flexural modulus is not decreased as fast as predicted results. Therefore, small amount of GF will not affect the application of rCF.     

Deformation near parallel cracks close to interface in bonded dissimilar plate

Tensile tests are carried out by using rectangular plate specimens extracted from the explosion clad plate. Artificial parallel cracks are made perpendicularly to the explosive interface in each specimen. When a tensile load is applied perpendicularly to the crack plane, strain, plastic deformation near cracks and crack opening displacement are examined by experiments as well as elasto-plastic finite element analysis. The effects of the material inhomogeneity, the change of material characteristics, the residual stress and the interaction between parallel cracks on the deformation behavior are revealed. The plastic zone around parallel cracks, at relatively low applied stress level, grows mainly ahead of and between two cracks. The interaction between parallel cracks on the crack opening displacement can be explained from the square of stress intensity factor at the low applied stress level and from the plastic deformation at the high applied stress level.     

Vanadium solid-salt battery: Solid state with two redox couples

We present the “vanadium solid-salt battery” (VSSB), which has high energy density, is low cost, is easily recycled, operates at ambient temperature, and has no requirement for special solvents. The VSSB contains two types of vanadium solid salts that are supported on carbon felts with a minimal amount of hydrosulfuric acid added to moisten the ion-exchange membrane. The optimized VSSB shows a cell potential of 1.34 V, excellent reproducibility for charging and discharging for nearly 100 cycles, a high energy efficiency (87%) and a high energy density (77 W h kg⁻¹ at 5 mA cm⁻² using the carbon felt XF208). The energy density is enhanced by 250-350% compared with conventional vanadium redox-flow batteries.     

Linear stability analysis on surface tension‐induced instability of LiBr aqueous solution absorbing water vapor

Linear stability analysis is applied to the absorption of water vapor into lithium bromide aqueous solution film when a small amount of surfactant is added to the solution. The condition under which an instability occurs and the role of the surfactant are investigated. The analysis shows that the film becomes unstable at a positive Marangoni number when the heat transfer is more determining than the mass transfer. In contrast, when the mass transfer is more determining, the film becomes unstable at a negative Marangoni number. As for LiBr aqueous solution, mass transfer is more rate determining than heat transfer, so the instability is promoted and maintained when the Marangoni number is negative. In the case of film flow absorption, the analysis shows that the disturbance of the film flow becomes more unstable in the transverse direction than in the longitudinal direction as the Reynolds number increases. © 2000 Scripta Technica, Heat Trans Asian Res, 29(7): 581–597, 2000     

Growth of yttria stabilized zirconia thin films by metallo-organic, ultrasonic spray pyrolysis

Randomly and preferentially oriented thin films of yttria stabilized zirconia (YSZ) have been prepared on fused quartz substrates by ultrasonic spray pyrolysis using zirconium octylate and yttrium octylate as metallo-organic precursors at a substrate temperature of 873–1023 K. The as-deposited films composed of fine columnar grains were found to be crystalline and transparent with a cubic fluorite structure. With increasing substrate temperature the growth rate and diameter of the columnar grains increased and the crystal habit showed a preferential orientation at the (111) plane.     

Thermal and mechanical transient behaviour of steel doors installed in non‐load‐bearing partition wall assemblies during exposure to the standard fire test

In this paper, the authors present experimental results and observations of four full‐scale standard fire tests on single‐leaf steel doors and steel frames installed in 3 × 3 m non‐load‐bearing partition walls. Three full‐scale fire tests were performed on steel doors installed in lightweight partition walls constructed by using steel C‐section studs with gypsum boards fixed on both sides. Two lightweight walls incorporated Rockwool cavity insulation, while the third lightweight wall was constructed without cavity insulation. The fourth fire test involved a steel door installed in a masonry partition wall. While the steel door leaf and door frames were identical in all four full‐scale tests, only the steel door installed in the masonry wall achieved the desired fire resistance rating of 30 min. The integrity criterion for fire resistance was determined for the scenario when the door opened away from the furnace. The duration of fire resistance according to the integrity criterion was found to be 38, 25 and 19 min for the same door when installed in masonry wall, uninsulated lightweight wall and insulated lightweight wall respectively. For the thermal insulation criterion of fire resistance, the scenario of the door opening into the fire was found to be the most onerous. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of Particle Sizes on Sintering Behavior of 316L Stainless Steel Powder

In rapidly evolving powder injection molding technology, the wide prevalence of various microstructures demands the powders of smaller particle sizes. The effects of particle size on the sintering behavior are critical to not only shape retention of microstructure but also its mechanical properties. This study investigates the effects of three different particle sizes on the sintering behavior of the 316L stainless steel (STS316L) samples, prepared by powder injection molding, via the dilatometry experiments. For this purpose, the STS316L powders of three different mean particle sizes, i.e., 2.97, 4.16, and 8.04 μm, were produced for STS316L. The samples for the dilatometry test were prepared through powder-binder mixing, injection molding, and solvent and thermal debinding. Dilatometry experiments were carried out with the samples in a H₂ atmosphere at three different heating rates of 3, 6, and 10 K/min. The shrinkage data obtained by dilatometry experiments was collected and analyzed to help understand the densification and the sintering behaviors in terms of particles size and heating rate. The master sintering curve (MSC) model was used to quantify the effects of particle sizes. In addition, we investigated the microstructure evolutions in terms of particles sizes.