Damage characterization in thin-ply composite laminates under out-of-plane transverse loadings

Composite laminates with thin-ply layers are expected to exhibit superior damage resistance to the standard composite laminates. This study investigated the damage characteristics of carbon fiber/toughened epoxy thin-ply laminates subjected to transverse loadings. Quasi-isotropic laminates were prepared using both standard prepregs and thin-ply prepregs in order to examine the effect of ply thickness on the damage accumulation processes. Clear difference on damage accumulation process between standard laminates and thin-ply laminates was identified; fiber fractures were susceptible to formation in thin-ply laminates. Finally, the reason of the difference on damage process was investigated using finite element analyses, and it was clarified that the accumulated delamination position has a significant effect on the fiber fractures during the indentation.     

Work Hardening,Dislocation Structure,and Load Partitioning in Lath Martensite Determined by <Emphasis Type="Italic">In Situ</Emphasis> Neutron Diffraction Line Profile Analysis

A lath martensite steel containing 0.22 mass pct carbon was analyzed in situ during tensile deformation by high-resolution time-of-flight neutron diffraction to clarify the large work-hardening behavior at the beginning of plastic deformation. The diffraction peaks in plastically deformed states exhibit asymmetries as the reflection of redistributions of the stress and dislocation densities/arrangements in two lath packets: soft packet, where the dislocation glides are favorable, and hard packet, where they are unfavorable. The dislocation density was as high as 10¹⁵ m^?2 in the as-heat-treated state. During tensile straining, the load and dislocation density became different between the two lath packets. The dislocation character and arrangement varied in the hard packet but hardly changed in the soft packet. In the hard packet, dislocations that were mainly screw-type in the as-heat-treated state became primarily edge-type and rearranged towards a dipole character related to constructing cell walls. The hard packet played an important role in the work hardening in martensite, which could be understood by considering the increase in dislocation density along with the change in dislocation arrangement.     

Hydrolysis of the potato glycoalkaloid alpha-chaconine by filamentous fungi

Three strains of filamentous fungi have been isolated from potato sprouts to obtain an enzyme degrading the glycoalkaloids. All of the strains hydrolyzed alpha-chaconine and not alpha-solanine when grown on the sprouts. From strain HP341, identified as Plectosphaerella cucumerina, the enzyme hydrolyzing alpha-chaconine was purified on columns of DEAE-Toyopearl and Phenyl-Toyopearl. The partially purified enzyme hydrolyzed alpha-chaconine to beta1-chaconine but not to beta2- or gamma-chaconine, suggesting that the enzyme is a rhamnosidase specific for the hydrolysis of the rhamnose (C1-C4) glucose linkage in alpha-chaconine. Conversion of alpha-chaconine to beta1-chaconine may be the first step of detoxification for filamentous fungi to grow on potato sprouts that accumulated antifungal alpha-chaconine.     

Sinterability of magnesium silicon nitride powder with yttrium oxide addition coated using the homogeneous precipitation method

The sinterability of magnesium silicon nitride (MgSiN₂) powder with yttrium oxide (Y₂O₃) addition was examined using the hot-pressing technique (31 MPa and N₂ atmosphere) at 1550°C for 90 min; the MgSiN₂ powder had been coated with 0–4 mass% of Y₂O₃ addition by a (urea-based) homogeneous precipitation method. Relative densities of the hot-pressed MgSiN₂ compacts (ceramics) with and without Y₂O₃ addition were 99.6% apart for the MgSiN₂ceramic with 4 mass% Y₂O₃ addition (98.4%). The thermal conductivities of the MgSiN₂ ceramics with 0–1 mass% Y₂O₃ addition were in the range of 20–21 W · m^–1 · K^–1 whilst the Vickers hardness was 19.7 GPa for the pure MgSiN₂ ceramic and decreased slightly with Y₂O₃ addition. Average fracture toughness values were in the range of 1.2–1.6 MPa · m^1/2 with significant trend being noted with regards to the ceramic containing 0.5 mass% of Y₂O₃. It was concluded that the use of homogeneous precipitation processing resulted in significant advantages regarding the densification, homogeneous microstructure, and fracture toughness despite the amount of Y₂O₃ addition being as low as 0.5 mass%.     

Two cases of ventricular parasystole associated with ventricular tachycardia

In two patients, ventricular parasystole (VP) was associated with ventricular tachycardia (VT), and in one patient, catheter ablation was successful. In patient 1, with dilated cardiomyopathy, VP led to VT, which converted to ventricular fibrillation. In patient 2, VP led to symptomatic nonsustained polymorphic VT. The origin of parasystolic focus was determined by endocardial mapping, and a radiofrequency current was delivered to patient 2. Both VP and VT disappeared immediately, and no recurrence has been observed during a follow-up of 8 months. Catheter ablation to the parasystolic focus was effective and a relationship between VP and VT was strongly suggested.     

Low-drive voltage intersectional waveguide optical switch usingGaInAs/InP MQW structure

A low-drive voltage intersectional waveguide optical switch using 1.6 μm GaInAs/InP MQW (multiple quantum well) structure, which was fabricated by only one-step epitaxial growth of MQW structure followed by a one-step pattern etching of the waveguide is demonstrated. Extinction ratio at the straight port of 9.9 dB and that at the reflection port of 4.4 dB were obtained at an applied voltage of -4 V     

Beam expanding fiber using thermal diffusion of the dopant

A beam-expanding fiber (BEF) for embedding optical devices has been fabricated by utilizing thermally induced Ge diffusion in silica single-mode fibers (SMFs). The preparation of fiber samples and their heat treatment is described, and the effect of heat on Ge dopant distribution and diffusion is discussed. Modal-intensity distributions were studied and found to confirm the broadening of the modal field distribution after heat treatment of the fiber. Localized heat treatment to obtain BEFs is considered, and device characteristics are discussed. The BEF can arbitrarily change the spot size of a propagating mode without changing the normalized frequency     

Confirmation of non-permitted dyes detected in Akasu (red vinegar) by LC/MS

Suitable liquid chromatography/mass spetrometry (LC/MS) conditions were examined for Amaranth, Red 2G (R2G), Azo Rubine (Azo), Fast Red E (FRE) and Brilliant Blue FCF, which were detected in Akasu, a red vinegar made in Hong Kong from sake lees, on both thin layer chromatography (TLC) and photodiode array high-performance liquid chromatography (PDA-HPLC). Molecular-related ions for each dye were detected with excellent sensitivity by LC/MS using electro-spray ionization with negative ion mode, capillary voltage 3.00 kV, cone voltage 50 V and desolvation temperature 400 degrees C. LC/MS analysis of refined Akasu under these conditions enabled us to obtain clear mass spectra of R2G, Azo and FRE, which were present at trace levels in the Akasu. The results were consistent with those from TLC and PDA-HPLC. These experiments suggested that LC/MS analysis is applicable for confirmation of dyes in food.     

Cloning and characterization of the dnaKJ operon in Acetobacter aceti

The dnaKJ operon of Acetobacter aceti was cloned and sequenced. The profile of the gene configuration was similar to that of other alpha-proteobacteria. In the DnaK and DnaJ proteins of A. aceti, the characteristic domains/motifs reported in other organisms were well conserved. This operon was transcribed in response to a temperature shift and exposure to ethanol/acetic acid. The overexpression of this operon in A. aceti resulted in improved growth compared to the control strain at high temperature or in the presence of ethanol, suggesting a correlation to resistance against stressors present during fermentation, although the overexpression did not increase the resistance to acetic acid.