Temperature dependence of flexural strength and microstructure of Al2O3/Y3Al5O12/ZrO2 ternary melt growth composites

New Al₂O₃/Y₃Al₅O₁₂(YAG)/ZrO₂ ternary Melt Growth Composites (MGCs) with a novel microstructure have been fabricated by unidirectional solidification. These MGCs displayed superior high-temperature strength characteristics. The flexural strength increases progressively in the range 650–800 MPa with a rise in temperature from room temperature up to 1873 K. These excellent high-temperature characteristics are closely linked to such factors as: a microstructure consisting of three-dimensionally continuous and complexly entangled single-crystal Al₂O₃ with a hexagonal structure, single-crystal YAG with a garnet structure and fine ZrO₂ with a cubic structure; characteristic dimensions of the microstructure of Al₂O₃/YAG/ZrO₂ ternary eutectic ceramics of around 2–3 m for YAG, around 2–3 m for Al₂O₃ and around 0.4–0.8 m for ZrO₂; and the fact that no amorphous phase is formed at interfaces between any of the phases.     

Phospholipid analysis of human eosinophils: High levels of alkylacylglycerophosphocholine (PAF precursor)

The phospholipid composition and fatty acid profiles of human eosinophils were studied. Extremely high levels of ether phospholipids were found in this type of cell, such as alkylacylglycerophosphocholine (GPC) and alkenyl-acylglycerophosphoethanolamine (GPE); these two ether phospholipids accounted for about three-fourths of the choline and ethanolamine glycerophospholipids (CGP and EGP), respectively. Fatty acid analyses revealed that very large portions of arachidonic acid (20∶4) were esterified to alkylacyl-GPC (92.0% in CGP) and alkenylacyl-GPE (86.6% in EGP), respectively. While high amounts of alkylacyl-GPC and the abundance of 20∶4 in this ether phospholipid have been observed in other types of blood cells of various animals, these percentages for human eosinophils are the highest among such cells. These results suggest that alkyl and alkenyl ether phospholipids play essential roles in human eosinophils in various physiological and pathological conditions.     

Production of platelet-activating factor by human normodense and hypodense eosinophils

Normodense eosinophils and neutrophils from normal donors produced considerable amounts of plateletactivating factor (PAF) when stimulated with ionophore A23187. PAF produced by eosinophils appeared to be degraded more rapidly than PAF formed by neutrophils, suggesting a higher activity of PAF-degrading enzyme in eosinophils. Substantial proportions of PAF newly formed by both eosinophils and neutrophils were shown to be cell-associated. By comparison, hypodense eosinophils obtained from a patient with idiopathic hypereosinophilic syndrome produced an extremely large amount of PAF and released much of it into the incubation medium. The accelerated formation of PAF in hypodense eosinophils may be related to various cardiovascular complications associated with hypereosinophilic syndrome. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.     

Buckling of plates with a hole under tension

An FEM analysis is made on the elastic buckling of plates, each of which has a hole and is subjected to tensile loading.In a general way, no attention is paid to the buckling of plates if they are subjected to a tensile load. However, when a plate has a hole, compressive stresses appear near the hole under a tensile load, and the stress may cause local buckling of the plate.In this paper, stress distributions and buckling behaviours of such plates under tension are studied. Aspect ratios, shapes of holes and so on, are adopted as parameters.Through the analysis, variations of buckling coefficients and buckling modes against aspect ratios are obtained. The effects of the hole shapes on the buckling strength are also discussed.     

Effect of polymer chain scission on photodegradation behavior of polystyrene/multi‐wall carbon nanotube composite

To clarify an effect of polymer chain scission on a polystyrene (PS)/multi‐wall carbon nanotube (MWNT) composite photodegradation, a relationship between the change of molecular weight and photodegradation behavior was studied. The MWNT loading brought about severe PS chain scission and led to the increase of the low molecular weight (less than 10⁵) fraction. The increase of the fraction was not proportional to the loading amount and showed the minimum at the 2% loading. The strange behavior was due to a rheological effect bringing about a decrease of shear stress in the composite preparation. An unsaturated end group was produced by the chain scission and became the photodegradation initiator leading to auto‐oxidation and crosslink reactions. The MWNT scavenged radical species and worked as an antioxidant. The coexistence of the unsaturated end group and MWNT made the photodegradation behavior complicated. However, the MWNT radical scavenging ability was considerably poor, and the MWNT had little ability to inhibit the photodegradation initiation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40362.     

Film Fabrication Using Poly(Vinylidene Fluoride) Solution Droplet

This study was conducted to investigate poly(vinylidene fluoride) (PVDF) film characteristics when fabricated using a proposed method. First, a PVDF film is fabricated by dropping and drying a PVDF solution droplet. In this film fabrication, some PVDF solution droplets are prepared by changing the combination of the PVDF solution drop quantity and PVDF concentration in solution. Second, their PVDF crystalline structure is analyzed using an x-ray diffraction device. Then, the PVDF film profile is measured using a 3D shape measurement machine. In addition, the degree of PVDF crystallinity is measured using differential scanning calorimetry. Third, the crystalline structure formation is investigated using Raman spectroscopy for a PVDF solution droplet under a drying process. Finally, we discuss the PVDF film crystalline structure and profile with the present experimentally obtained results toward point drawing of PVDF, leading to the creation of free-form sensor and actuators.