Development of a Structure for Blast Wave Mitigation

The internal structure of a blast containment container has been developed and examined by experiments involving the explosion of a high explosive. A steel pipe was selected as an effective structure for blast mitigation, because it dramatically reduces the blast wave in the radial direction near the explosion source. To also reduce the blast wave in the axial direction, two types of model structures consisting of a steel pipe as the main part were examined by both high‐speed photography and pressure measurements of the blast waves. A 0.34‐scale internal structure was constructed by combining these structures. To induce a powerful mitigation effect, the internal structure was filled with a shock‐absorbing material. The peak pressures of C4 explosions in free air were obtained on the basis of the published blast wave data for TNT explosions in free air using an equivalent weight of 1.37. The peak pressures of the blast waves from the structures for all cases were compared with the blast wave data for C4 explosions in free air to estimate the blast mitigation effect. As a result it was estimated that the internal structure not only eliminates the blast pressure in the radial direction but also reduces the blast wave in the axial direction by 36 %. By combining the effects of the internal structure and the shock‐absorbing material, the structure can reduce the peak pressure by 75 %.     

Early construction and operation of the highly contaminated water treatment system in Fukushima Daiichi Nuclear Power Station (IV) - Assessment of hydrogen behavior in stored Cs adsorption vessel

Hydrogen diffusion behavior in a cesium adsorption vessel is assessed. The vessel is used to remove radioactive substance from contaminated water, which is proceeded from Fukushima accident. Experiment and numerical calculation are conducted to clarify the characteristics of natural circulation in the vessel. The natural circulation arising from the temperature difference between inside and outside the vessel is confirmed. We develop an evaluation model to predict the natural circulation and its prediction agrees well with the results obtained by the experiment and the calculation. Using the model, we predict steady and transient behavior of hydrogen concentration. Results indicate that hydrogen concentration is kept lower than the flammability limit when the short vent pipe is open.     

Influence of the carbon surface on cathode deposits in non-aqueous Li–O2 batteries

Cup-stacked carbon nanotubes (CSCNT) with different surface properties were used for the non-aqueous Li–O₂ battery cathodes, and then examined at high magnification to understand how the discharge products were deposited on the cathode. As-prepared CSCNT based cathode had many reactive edges consisting of truncated conical graphene layers. After discharge, discharge products with average particle size 50 nm covered a nanotube, resulting in a layer-like texture. On the other hand, a heat-treated CSCNT based cathode was composed of edges terminated by graphitization of several graphene layers. After discharge, the size of the products was almost the same but the products were agglomerated, forming a bulky morphology. It was, thus, found that the carbon surface structure was closely related with the morphology of the cathode deposits after discharge. First principles calculations also indicated that no terminated edges acted as preferential active sites in adsorbing and storing the reaction species. It was, therefore, concluded that the active edges of the carbon surface were indispensable for controlling the morphology of cathode deposits and improving the battery performance.     

One-year weekly survey of noroviruses and enteric adenoviruses in the Tone River water in Tokyo metropolitan area, Japan

To investigate the actual fluctuations in the concentrations of noroviruses (NoVs) GI and GII, and enteric adenoviruses (EAdVs) in river water and its relationship with the number of acute infectious gastroenteritis patients, one-year weekly quantitative monitoring of NoVs GI and GII and EAdVs was performed in the Tone River in Japan where the surface water is utilized for the main production of drinking water for the Tokyo Metropolitan Area from October 2009 to September 2010. Noroviruses GI and GII and EAdVs were detected in 28 (54%), 33 (63%), and 23 (44%) of the 52 samples (1 L each), respectively. The concentrations of NoVs GI and GII and EAdVs fluctuated strongly and were more abundant in winter and early spring. The concentration of NoVs GI was transiently greater than 10,000 copies/L. The number of acute infectious gastroenteritis patients in the upper river basin was highly correlated with all the viral concentrations, while general microbial indicator data such as turbidity and heterotrophic plate count were independent of viral concentration as suggested in previous studies. To the best of our knowledge, this is the first study that clearly shows the strong correlation of the number of gastroenteritis with virus contamination in lower river basin.     

Characteristics and functional properties of gelatin from splendid squid (Loligo formosana) skin as affected by extraction temperatures

Gelatin was extracted from the skin of splendid squid (Loligo formosana) at different temperatures (50, 60, 70 and 80 °C) with extraction yield of 8.8%, 21.8%, 28.2%, and 45.3% (dry weight basis) for G50, G60, G70 and G80, respectively. Gelatin from the skin of splendid squid had a high protein content (∼90%) with low moisture (8.63–11.09%), fat (0.22–0.31%) and ash contents (0.17–0.68%). Gelatin extracted at higher temperature (G80) had a relatively higher free amino group content than gelatin extracted at lower temperatures (G50, G60 and G70) (P < 0.05). All gelatins contained α- and β-chains as the predominant components. Amino acid analysis of gelatin revealed the high proline and hydroxyproline contents for G50 and G60. FTIR spectra of obtained gelatins revealed the significant loss of molecular order of the triple-helix. The gel strength of gelatin extracted at lower temperature (G50) was higher than that of gelatins extracted at higher temperatures including G60, G70 and G80, respectively. The net charge of G50, G60, G70 and G80 became zero at pHs of 6.84, 5.94, 5.49, and 4.86, respectively, as determined by zeta potential titration. Gelatin extracted at higher temperature (G80) had the lower L* value but higher a* and b* values, compared with those extracted at lower temperatures (P < 0.05). Emulsion activity index decreased, whilst emulsion stability index, foam expansion and stability increased as the concentration (1–3%) increased (P < 0.05). Those properties were governed by extraction temperatures of gelatin. Thus gelatin can be successfully extracted from splendid squid skin using the appropriate extraction temperature.     

Numerical simulation of gas–liquid–solid three-phase flow using particle methods

We want to simulate, based on particle methods, the dynamic behavior of multi-phase flows in a gas–solid–liquid mixture system. With the governing equations discretized within the finite volume particle method, the effects of contact and collision between solid particles were modeled by the distinct element method. Applicability of the viscosity model and an empirical drag force model were confirmed for the hydrodynamic interactions between solid particles and fluid. Simulations were performed of a single bubble rising in a tank of stagnant solid particle–liquid. The results for the dynamic behavior indicate that the present computational framework of particle-based simulation method may be useful for numerical simulations of multi-phase flow behavior in a solid particle–fluid mixture system.     

Determination of the surface band bending in InxGa1−xN films by hard x-ray photoemission spectroscopy

Core-level and valence band spectra of In_xGa_1−xN films were measured using hard x-ray photoemission spectroscopy (HX-PES). Fine structure, caused by the coupling of the localized Ga 3d and In 4d with N 2s states, was experimentally observed in the films. Because of the large detection depth of HX-PES (∼20 nm), the spectra contain both surface and bulk information due to the surface band bending. The In_xGa_1−xN films (x = 0–0.21) exhibited upward surface band bending, and the valence band maximum was shifted to lower binding energy when the mole fraction of InN was increased. On the other hand, downward surface band bending was confirmed for an InN film with low carrier density despite its n-type conduction. Although the Fermi level (E_F) near the surface of the InN film was detected inside the conduction band as reported previously, it can be concluded that E_F in the bulk of the film must be located in the band gap below the conduction band minimum.     

Design of a GMPLS control plane with PCE-based impairment-aware full restoration capability for translucent WSON: Enabling techniques,service demonstration,and performance evaluation

The control plane techniques based on the Generalized Multi-Protocol Label Switching (GMPLS) and Path Computation Element (PCE) architectures are promising candidates for potential industrial deployment in Wavelength Switched Optical Networks (WSON), because they can greatly reduce operational expenses and improve the network intelligence. Moreover, link failures have a critical effect on WSON, since a single failure may result in the loss of a huge amount of data. In light of this, in this paper, we detail the design and implementation of a GMPLS control plane, with PCE-based, impairment-aware, full restoration capability for translucent WSON. We investigate the enabling techniques for such a PCE/GMPLS control plane by surveying a series of solutions, and, based on these enabling techniques, we present an experimental demonstration of service recovery for uncompressed video stream in a GMPLS controlled WSON with PCE-based full lightpath restoration. We also quantitatively evaluate the performance of the PCE-based full restoration, and compare it with the PCE-based pre-planned restoration and the PCE-based pre-computed dynamic restoration in terms of signaling latency and restorability. To the best of our knowledge, it is the first time that the PCE-based full restoration is experimentally investigated on an actual GMPLS controlled WSON testbed, which is beneficial for verifying the overall feasibility and efficiency of the proposed solutions, obtaining valuable insights for its future deployment in a real operational scenario, and providing active contribution in support of the on-going Internet Engineering Task Force (IETF) standardization activities.     

Molecular Species of Phospholipids with Very Long Chain Fatty Acids in Skin Fibroblasts of Zellweger Syndrome

The ratio of C_26:0/C_22:0 fatty acids in patient lipids is widely accepted as a critical clinical criterion of peroxisomal diseases, such as Zellweger syndrome and X-linked adrenoleukodystrophy (X-ALD). However, phospholipid molecular species with very long chain fatty acids (VLCFA) have not been precisely characterized. In the present study, the structures of such molecules in fibroblasts of Zellweger syndrome and X-ALD were examined using LC–ESI–MS/MS analysis. In fibroblasts from Zellweger patients, a large number of VLCFA-containing molecular species were detected in several phospholipid classes as well as neutral lipids, including triacylglycerol and cholesteryl esters. Among these lipids, phosphatidylcholine showed the most diversity in the structures of VLCFA-containing molecular species. Some VLCFA possessed longer carbon chains and/or larger number of double bonds than C_26:0-fatty acid (FA). Similar VLCFA were also found in other phospholipid classes, such as phosphatidylethanolamine and phosphatidylserine. In addition, VLCFA-containing phospholipid species showed some differences among fibroblasts from Zellweger patients. It appears that phospholipids with VLCFA, with or without double bonds, as well as C_26:0-FA might affect cellular functions, thus leading to the pathogenesis of peroxisomal diseases, such as Zellweger syndrome and X-ALD.     

The deformation behavior of polypropylene film under high strain rates

The relationship between stress and strain for polypropylene film was studied under strain rates from 0.13 to 5.21 s^?1 in order to study the deformation behavior of film under higher strain rates than previous studies. Uniform thickness was obtained in the strain rates from 2.08 to 5.21 s^?1 at 435 K, or from 2.08 to 3.13 s^?1 at 437 K. The temperature rise of film due to the generation of heat from plastic strain influenced the relationship between stress and strain, in particular, at high strain rates and low temperature. Material constants for the constitutive equation of film were determined using the measurements from 2.08 to 5.21 s^?1 at 435 K and from 2.08 to 3.13 s^?1 at 437 K. Film thicknesses during and after transverse direction stretching were successfully predicted by applying the material constants obtained. The authors concluded that the material constants should be determined by applying the stretching conditions, under which there is little or no effect from heat generation and under which film can be stretched uniformly in thickness. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers