Cesium-adsorption capacity and hydraulic conductivity of sealing geomaterial made with marine clay,bentonite, and zeolite

Great amounts of soil and waste contaminated with radioactive cesium have been generated due to the decontamination work after the Fukushima Daiichi Nuclear Power Plant accident. The aim of this study is to develop a sealing geomaterial for use at the disposal facilities of the soil and waste constructed in the maritime environment. The geomaterial consists of marine clay, bentonite, and zeolite. The hydraulic conductivity and cesium-adsorption performance of the geomaterial were examined through laboratory tests with different proportions of bentonite and zeolite added to marine clay. It was concluded that the hydraulic conductivity could be reduced to the required level by increasing the amount of bentonite and that the cesium-adsorption capacity could be enhanced by increasing the amount of zeolite.     

On-off switching properties of one-dimensional photonic crystals consisting of azo-functionalized polymer liquid crystals having different methylene spacers and polyvinyl alcohol

In this paper, photoresponsive behavior of multi-bilayered films having precisely controlled layer thickness prepared by stacking an azo-functionalized polymer liquid crystal, PMAzXAc, and polyvinyl alcohol alternatively, PVA, is described. The multi-bilayered films were found to reflect a light of specific wavelength depending on the layer thickness and refractive index, and showed the reversible change in the reflection intensity by irradiation with visible and UV lights. The change in the reflection intensity was brought about by change in the molecular orientation of PMAzXAc between an out-of-plane orientation and a photo-induced isotropic state, and was strongly dependent on the number of methylene spacer of PMAzXAc linking the azobenzene side group with the acrylate polymer main chain. PMAz6Ac with hexa-methylene spacer showed the largest change in the reflection intensity, while smaller change in the reflection intensity was observed for PMAzXAc having shorter or longer methylene spacer than 6. The effect of the methylene spacers on the photochemical change in the molecular orientation of azobenzene chromophores in the multi-bilayered films will be discussed.     

Synthesis and optical properties of azobenzene side chain polymers derived from the bifunctional fumaric acid and itaconic acid

Three type polymers containing the same azobenzene side chain group with different backbone structures, poly(DMAz6Fm), poly(DMAz6It) and poly(MAz6Ac) derived respectively from fumaric acid, itaconic acid and acrylic acid, were synthesized. The dependence of photo-response properties on the polymeric architecture was investigated for the solutions and films. By irradiation of the linearly polarized light (436 nm), uniaxial orientations of the thin films were induced and anisotropic properties were investigated by measurements of the order parameters and birefringence values.     

Effect of Sliding History on Super-Low Friction of Diamond-Like Carbon Coating in Water Lubrication

Water lubrication using diamond-like carbon (DLC) coatings is regarded as being a promising eco-friendly technology. However, it has been reported that delamination of DLC coatings occurs in water. The authors clarified that the application of friction in ambient air prior to self-mating DLC water lubrication, in addition to the suppression of DLC delamination, caused the friction coefficient to decrease more than when no processing is performed in the boundary lubrication region. When compared to the case when there was no pre-sliding, in terms of the wear scar, in this case, a much more hydrophilic and smoother surface was formed. Therefore, the friction-reducing process in water due to the presence of a sliding history (pre-sliding in ambient air) was clarified by an analysis of the DLC geometry, structure, chemical state and an in situ analysis that can measure the friction properties and the chemical state of DLC. We clarified that the process in which the oxidation and structural changes of the DLC proceed at the time of pre-sliding in ambient air using in situ Fourier transform infrared spectroscopy–attenuated total reflection. It was also revealed that the OH termination subsequently accelerated rapidly due to the friction in water after pre-sliding process. In addition, a time-of-flight secondary ion mass spectrometry analysis revealed that this OH group was derived from the lubricating water and unlike the case in which there was no pre-sliding in ambient air, the rate at which OH terminates increased considerably.     

Lifetime prediction of woven GFRP laminates under constant tensile loading in hydrothermal environment

This study aims to investigate the effects of a hydrothermal environment on the creep behavior of woven glass fiber reinforced plastics (GFRPs) and to propose a method for predicting their lifetime. Toward this end, experiments were carried out in air and deionized water at 40, 60, 80 and 95 ^°C. Static tensile tests of woven GFRP were conducted in air and in deionized water to evaluate its mechanical properties and to determine suitable experimental conditions for subsequent constant tensile load tests. The mechanical properties of the woven GFRP decreased with an increase in temperature and with water immersion. Constant tensile load tests were also conducted in air and in deionized water to investigate the creep behavior and fracture time. The fracture time decreased with an increase in stress and water temperature and demonstrated the possibility of a threshold stress for fracturing. In addition, the fracture time during each constant tensile load test was predicted using a modified Reiner–Weissenberg (R-W) criterion, which is a failure criterion for linear viscoelastic materials based on the accumulation of dissolved energy within the GFRP. In this study, the R-W criterion was modified to consider the effects of degradation and its acceleration, which are due to the applied stress and immersion in a solution. The predicted results were in good agreement with the experimental data when considering the effects of hydrothermal aging.     

Numerical computation of two-loop box diagrams with masses

A new approach is presented to evaluate multi-loop integrals, which appear in the calculation of cross-sections in high-energy physics. It relies on a fully numerical method and is applicable to a wide class of integrals with various mass configurations. As an example, the computation of two-loop planar and non-planar box diagrams is shown. The results are confirmed by comparisons with other techniques, including the reduction method, and by a consistency check using the dispersion relation.     

Microfluidic Spinning of Cell‐Responsive Grooved Microfibers

Engineering living tissues that simulate their natural counterparts is a dynamic area of research. Among the various models of biological tissues being developed, fiber‐shaped cellular architectures, which can be used as artificial blood vessels or muscle fibers, have drawn particular attention. However, the fabrication of continuous microfiber substrates for culturing cells is still limited to a restricted number of polymers (e.g., alginate) having easy processability but poor cell–material interaction properties. Moreover, the typical smooth surface of a synthetic fiber does not replicate the micro‐ and nanofeatures observed in vivo, which guide and regulate cell behavior. In this study, a method to fabricate photocrosslinkable cell‐responsive methacrylamide‐modified gelatin (GelMA) fibers with exquisite microstructured surfaces by using a microfluidic device is developed. These hydrogel fibers with microgrooved surfaces efficiently promote cell encapsulation and adhesion. GelMA fibers significantly promote the viability of cells encapsulated in/or grown on the fibers compared with similar grooved alginate fibers used as controls. Importantly, the grooves engraved on the GelMA fibers induce cell alignment. Furthermore, the GelMA fibers exhibit excellent processability and could be wound into various shapes. These microstructured GelMA fibers have great potential as templates for the creation of fiber‐shaped tissues or tissue microstructures.