Preparation of monodispersed polymer-modified silica particles by radical polymerization using silica colloid and introduction of functional groups on the composite surface

Summary Radical polymerizations of vinyl monomers using a initiator of 2,2-azobis(2-amidinopropane) dihydrochloride on monodispersed silica colloid led to formation of spherical polymer/SiO₂ composites, retained particle size. Addition of hydroxypropyl cellulose to the reaction system resulted in yielding excellent dispersible composites into ethanol by short period ultrasonic irradiation. The polymerization of styrene in the presence of mercapto-amine or carboxylic acid derivatives could successfully introduce amino or carboxyl group on the Poly(styrene)/SiO₂ composite.     

Progressive failure analysis of carbon-fibre/epoxy composites laminates to study the effect of stitch densities under in-plane tensile loading

Through thickness reinforced stitched laminates with different stitch densities (0.11 and 0.028?mm^?2) were studied in order to analyse effects on laminate behaviour, under in-plane tensile loading based on continuum mechanics. Multi-layered stitched laminates with the stacking sequence [+45/90/?45/0₂/+45/90₂/?45/0]_s were modelled on a lamina-wise basis to analyse the macroscopic damage and local stress–strain constitutive behaviour. Interfaces between lamina and stitch yarns were assumed to be perfectly glued and were modelled by the contact capability. Discretisation procedures using the principle of virtual work were applied in addition to discretisation of the contact traction. Progressive failure analysis with Puck’s failure criteria was conducted to characterise the failure behaviour of the laminate. This analysis showed that reinforcement density is one of the key factors affecting strength, stiffness and crack propagation in composite laminates. By suppressing the damage initiation, densely stitched laminates showed 15.2% higher in-plane stiffness than moderately stitched laminates. The results obtained by the finite element technique are consistent with the experimental results.     

Durability of radiation-sterilized polymers. I. Estimation of oxidative degradation in polymers by chemiluminescence

In relation to sterilization of medical supplies, the degree of degradation by γ-ray and electron beam irradiations of homopolypropylene (HP), copolypropylene (CP, coplymer including 6% of ethylene unit) and polymethylpentene were compared, and chemiluminescence (CL) of irradiated polymers were measured. HP degraded extremely around the sterilization dose (2.5 Mrad) by either γ-ray or electron beam irradiations. In the case of CP and polymethylpentene, stabilities of polymers far differed between γ-ray and electron beam irradiations. The polymethylpentene was more stable than the polypropylenes against irradiation. The counts of CL emitted by recombination of peroxy radical (ROO ·) increased with increasing dose, reflecting degrees of oxidation of polymers. The degradation of polymers was independent of irradiation sources, rather it depended on the degree of oxidation. It was found that CL analysis are favorable for estimation of degradation in irradiated polymers.     

Electron spin resonance studies of γ-irradiated cellulose. II. Free radicals in accessible regions to water in cellulose I and cellulose II

The types of free radicals produced in the water-accessible regions of cellulose I and cellulose II fibers by γ-irradiation in nitrogen atmosphere at room temperature were studied by ESR spectroscopy. The ESR spectra of the irradiated cellulose I and II change by contacting the fibers with water, and after immersion in water the spectral shape depends on the orientation of the fiber axes to the magnetic field. These spectra are probably related to the free radicals generated in the highly ordered regions inaccessible to water in irradiated cellulosic fibers. The ESR spectrum of free radicals generated in decrystallized cellulose after irradiation consists of a singlet and a doublet. When the ESR spectra of free radicals formed in the highly ordered regions of cellulose I and II and the singlet and the doublet are combined in adequate ratio, the constructed spectra are similar to those of the radicals scavenged by water in the irradiated cellulose I and II fibers. From these facts, the spectra due to the free radicals in the water-accessible regions in irradiated cellulose I and II are considered to consist of the singlet and the doublet formed by free radicals in the typical amorphous regions and the spectra of other types of radicals generated in the semicrystalline regions.     

Applicability of Ozonation Combined with Electrolysis to 1,4-Dioxane Removal from Wastewater Containing Radical Scavengers

In this paper, applicability of ozonation combined with electrolysis as an advanced oxidation process for the removal of 1,4-dioxane from synthetic wastewater, has been studied. The combined process easily decomposed 1,4-dioxane, and two byproducts were detected in treated water. Although bicarbonate alkalinity was a strong radical scavenger, its influence was abated by air-stripping of carbon dioxide at the anodic compartment of the reactor. Free chlorine produced through anodic oxidation of chloride ion accelerated the COD removal from wastewater, despite the fact that this ion acted as a weak radical scavenger. The combined process was demonstrated to be applicable to the treatment of wastewater containing high concentration of bicarbonate alkalinity and chloride ions.     

A memory‐in‐pixel reflective‐type LCD using newly designed system and pixel structure

A 7.03‐in. extended graphics array reflective LCD prototype has been developed by using memory‐in‐pixel (MIP) technologies with a newly designed system and pixel structure. The MIP system comprising a MIP backplane and a display driver has been optimized to reduce power consumption. The MIP backplane has specific circuits that allow accessing row drivers randomly, and the display driver manages which row should be accessed. Thus, the system is capable of showing a mixture of still and moving images, resulting in low power consumption. A dithering block embedded in the display driver enables to select an appropriate dithering algorithm according to the types of images and the position on the screen. In addition, the novel pixel structure, “three divided patterns”, has been designed to improve image quality and to provide visibility in dark environments. The latter is based on a novel approach; interpixel area is used for an aperture to transmit light from the backlight, and the fringe field from adjacent pixel electrodes is used to control LC directions. The feature of the pixel structure is also effective for obtaining equivalent gamma between reflective and transmissive images.     

International comparison of bubbles and bubble indicators

The purpose of this paper is to analyze the financial turmoil of the US subprime loan crisis of mid-Noughties and to compare it with the Japanese asset bubble of late 1980s. While examining the two crises, it compares the monetary policies of both countries, focusing on the excess liquidity and expansion of bank loans that were seen. This paper develops several bubble indicators, including the ratio of real estate loans to total loans, the loan-to-GDP ratio, and housing affordability. In order to develop these indicators, it is necessary to compare banking behavior in both Japan and the United States, as banks in both countries were making loans beyond the point of profit maximization. Property prices and monetary policy in both countries influenced banking behavior significantly. The bubble indicators developed in this paper can be used as early warning indicators for future bubbles.     

Effect of Deuterium Ion Implantation on Microstructures of Fe-M （M=V,W, Ta） Alloys

To study the effect of tungsten, vanadium and tantalum on the microstructures in CLAM (China Low Activation Martensitic) steel after irradiation respectively, the microstructures of Fe-M (M= V ,W, Ta) model alloys were investigated after implanted deuterium ions using an ion accelerator at 773 K. After implanted deuterium ion, TEM (Transmission Electron Microscope) observation and EDX (Energy Dispersive X-ray Spectrom) analysis have been carried out. The result showed that tiny voids were observed in all model alloys after implanted the same dose of deuterium ions. The swelling rate in FeTa alloy was the smallest among the three alloys. Unlike FeW and FeV alloys, there was the segregation in FeTa alloy under a fluence of 5×1017 D + /cm2 at 773 K. A theoretical analysis showed that the void growth in FeTa alloy slowed down due to tantalum segregation near voids. It indicates that tantalum plays an important role in the improved irradiation resistance of CLAM steel.     

Preparation of monophasic titanium sub-oxides of Magnéli phase with enhanced thermoelectric performance

Titanium sub-oxides of Magnéli phase are considered as earth-abundant, non-toxic materials for thermoelectric application at high temperature, but very limited investigation has been reported mainly owing to the difficulty lying in obtaining monophasic material. Herein we describe a facile strategy to prepare monophasic Ti₉O₁₇ and Ti₄O₇ powder, in which the single Ti₉O₁₇ phase is obtained for the first time. After spark plasma sintering, the thermoelectric properties of monophasic Ti₉O₁₇ and Ti₄O₇ ceramics are studied comparatively. Despite the one magnitude lower electrical conductivity, Ti₉O₁₇ shows higher power factor compared with Ti₄O₇ due to the large Seebeck coefficient. Moreover, with the low electronic thermal conductivity, sub-micron scaled grain size and nano-scaled crystallographic shear plane, the Ti₉O₁₇ ceramic exhibits even lower thermal conductivity compared to Ti₄O₇, leading to a ZT of 0.16 at 764 K, which is the best thermoelectric performance among reported Magnéli phases.