Proposal for an engineering definition of a fatigue crack initiation unit for evaluating the fatigue limit on the basis of crystallographic analysis of pearlitic steel

In this study, in order to define a fatigue crack initiation unit, the relationship between the fatigue crack initiation process and the crystal structure in the pearlitic steel used for railroad rails was examined and fatigue tests, focusing on crack initiation, were performed. The fracture surfaces were analyzed using a scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). The crystal structure of the pearlitic steel is composed of “pearlitic colonies” that have the same lamellar structure direction and “pearlitic blocks” that have the same ferrite crystal direction. The SEM and EBSD results revealed that the crack initiation depends on the pearlitic colonies. Therefore, we defined the characteristic dimension for fatigue crack initiation as the pearlitic colony size. However, for safety purposes, the pearlitic block size should be considered the engineering definition of the fatigue crack initiation unit, since decreasing the pearlitic block size should cause an improvement in the fatigue limit of pearlitic steel.     

Phosphorescence of Large Polycyclic Aromatic Ketones

Phosphorescence measurements were performed for 6H-benzo[cd]-pyren-6-one (l), 2-nitro-benzo[hi]chrysen- 13-one (2), 2-bromo-di-benzo[a, de]anthracen- 13-one (3), and 7H-benzo[hi]chrysen-7-one (4) in an ethanol-ether-toluene mixed solution and the character of their lowest excited triplet (T₁) states were investigated. The phos horescence of the compounds appears at about 5,200 – 6,000 cm^?1 to the red of their fluorescence, indicating that the T, states have ππ^* character. On the other hand, the short phosphorescence lifetimes, 10 – 60 ms, suggest nπ^* transitions. Such a duality of the T₁ state seems to be characteristic of large polycyclic aromatic ketones. The polarized emission study revealed that the duality is ascribed to strong mixing of ππ^* and nπ^* natures.     

Studies of Alkali Fusion of Benzanthrone By-Producing Isoviolanthrone A

The relation between the yields of three isomers of violanthrone--violanthrone A (VOA), violanthrone B (VOB), and isoviolanthrone A (isoVOA)--and the condition of the alkali fusion of benzanthrone have been studied. When the method of alcoholic alkali fusion was applied to benzanthrone at low temperature, the major product was VOB. On the other hand, it was reported by Di Raddo et al. (2) that isoVOA was not obtained as a by-product under proper conditions (alkali fusion at high temperature) of synthesizing VOA. However, the result by the present authors is that 6 ～ 7 percent of the A compound is isoVOA.     

Isolation and characterization of a rheumatoid arthritis-specific antigen (RA-A47) from a human chondrocytic cell line (HCS-2/8)

Two types of 47 kDa antigen specifically recognized by sera from rheumatoid arthritis (RA) patients were isolated from the membrane fraction of a human chondrosarcoma-derived chondrocytic cell line (HCS-2/8) by a 2-step procedure: preparative SDS-PAGE and reverse-phase HPLC. An N-terminal amino acid sequence in one of the 47 kDa antigens, named RA-A47, had 81% homology to that deduced from the DNA sequence of the colligin gene which is reported as human hsp47 gene, and 100% homology to that deduced from the DNA sequence of colligin-2 gene, a homologue of colligin. The RA-A47 cross-reacted with a monoclonal antibody raised against chick heat shock protein (Hsp) 47 and bound to gelatin. The expression of the ra-a47 gene was enhanced by heat shock treatment and TGF-beta stimulation. These findings suggest that RA-A47 is a Hsp47-like protein, presumably the product of the colligin-2 gene, and that a collagen-specific molecular chaperone(s) such as Hsp47 and/or RA-A47 is involved in cartilage destruction in RA.     

CD14-positive and nonspecific esterase-positive neutrophils in a patient with refractory anemia with excess of blasts in transformation

A 34-year-old man was admitted with lumbago and anemia in November 1992. Hematological examination revealed an Hb 9.2g/dl, WBC count 13,500 microliters (33% blasts), and monocyte count 3,400/microliters. Bone marrow examination showed hyperplasia with dysplasia in trilineage blood cells and increased blasts (21.8%). A diagnosis of refractory anemia with excess of blasts in transformation (RAEB in T) was made. Cytochemical examination revealed the neutrophils in the peripheral blood were 66.5% positive for alpha-naphthyl butyrate esterase inhibited by sodium fluoride, 4.0% positive for peroxidase and 75% positive for alkaline phosphatase. The results of immuno-alkaline phosphatase stainings (avidin biotin alkaline phosphatase complex method) of neutrophils were as follows; CD16 (94.5%), CD24 (91.0%), CD13 (93.0%), CD14 (52.5%), CD33 (39.0%), CD36 (16.5%), HLA-DR (17.0%). These neutrophils exhibited monocyte-specific features and failed to show characteristics of neutrophils.     

Photoluminescence Measurement of Er,O-Codoped GaAs Under a Pulsed Magnetic Field up to 60 T

We have performed photoluminescence (PL) measurements on magnetic semiconductor GaAs:Er,O under pulsed magnetic fields up to 60 T at 4.2 K. We have succeeded in observing the Zeeman effect of the ⁴ I _13/2→⁴ I _15/2 PL transition of the Er³⁺ in the high magnetic field region. The effective g-factor of the dominant PL transition is estimated to be g _eff=1.54±0.04. This value is in reasonable agreement with the theoretical value based on the crystal field theory.     

High Field ESR Measurements of <Emphasis Type="Italic">S</Emphasis>=1/2 Quasi One-Dimensional Antiferromagnet Cu<Subscript>3</Subscript>Mo<Subscript>2</Subscript>O<Subscript>9</Subscript>

The tunneling of a Bose-Einstein condensate in a double-well potential causes the coherent atomic oscillations. The damping mechanism is employed to enhance the tunneling. Our numerical simulations show that the damping mechanism can firstly cause the atoms return to the initial well and form the metastable state. After that, the continuative dissipation of the energy of the system causes the unidirectional quantum coherent atomic tunneling, which just induces the system to transfer from the metastable state to the ground state.     

Numerical Analysis of the Erosion and the Transport of Fine Particles within Soils Leading to the Piping Phenomenon

About 50% of the world's dam failures are triggered by piping, which is a primary cause of embankment breaks. The phenomenon of piping results from the erosion of soil particles and their transport within a soil mass. In this paper, a numerical method is proposed to analyze the erosion within soils and the transport of eroded soil particles by adopting the concept of the erosion rate of soils. In such an analysis, the saturated-unsaturated seepage flow of the pore liquid, the detachment of the soil particles from the soil fabric, and the migration of the eroded particles are taken into consideration, and the equations related to the conservation of the pore liquid and the eroded soil particles are numerically solved. This numerical simulation allows for the procurement of the temporal alteration and the spatial distribution of the porosity, the particle size distribution, and the concentration of the detached soil particles in the pore liquid, as well as the distribution of pore liquid pressure. The results have revealed that the method can reproduce the experimental data from previous studies on the internal erosion of soils and that it qualitatively predicts, from the numerical experiments, the typical development of piping within soils, such as soil blocks and embankments, as the solutions to the initial and the boundary value problems of the governing equations.