Complex formation in a ternary system composed of lauroamphoglycinate, oleic acid, and water

The formation of a complex, composed of lauroamphoglycinate (LG), oleic acid (OA) and water, was investigated, and this system was applied to emulsification. The complex was formed in the water-rich area (more than 90% in this system) at a molar ratio of OA to LG from 1 to 3, where two-phase systems of water and the complex existed. The interaction between LG and OA, both in the aqueous solution and at the interface of liquid paraffin dissolving the OA and LG solution, was studied by pH measurements and interfacial tension measurements, respectively. The results implied that LG and OA were linked stoichiometrically, both in aqueous solution and at the interface, and formed complexes. X-ray diffraction patterns and the strong hydrophobicity showed that the equimolar complex composed of LG, OA, and water was a liquid crystal with a reversed hexagonal structure. The reversed hexagonal liquid crystal was capable of solubilizing a certain amount of liquid paraffin in its alkyl group parts while maintaining its hexagonal structure. These results suggest the possibility to prepare a W/O-type emulsion by using the liquid crystal formed by LG, OA, partial liquid paraffin, and water as the continuous phase. The authors could obtain a stable W/O emulsion without coalescence of the water droplets that contained a substantial amount of water (approximately 90%). Furthermore, various types of emulsions, O/W, W/O, W/O/W, could be prepared by changing the ratio of LG and OA.     

Synthesis and thermal stability of novel anion exchange resins with spacer chains

Spacer-modified anion exchange resins were prepared by suspension copolymerization of ω-bromoalkylstyrenes or ω-bromoalkyloxymethylstyrenes with 2–8 mol % of divinylbenzene, followed by quaternization with trimethylamine. The thermal stability of the spacer-modified anion exchangers of the OH form was examined by standing the resins in deionized water at 100–140°C for 30–90 days. The anion exchangers with alkylene chains such as butylene or heptylene groups between the benzene ring and the quaternary nitrogen exhibited higher thermal stability compared with commercial, strongly basic anion exchangers with benzylic ammonium groups. The thermal stability of the exchangers with butyleneoxymethylene or hexyleneoxymethylene spacers was also higher than that of the commercial exchangers. The exchanger with the propyleneoxymethylene spacer, however, had less stability than did the commercial ones. The decreased stability of this spacer-modified exchanger is due to the accelerated degradation of the spacer chain via Hofmann elimination. The excellent stability of the anion exchangers with alkylene or alkyleneoxymethylene spacers, except propyleneoxymethylene, results from the structure of the exchangers, where there are no reactive benzylic carbons, which are attached directly to the quaternary nitrogen. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1161–1167, 1997     

Electrochemical reaction engineering of polymer electrolyte fuel cell

Although fuel cells can be considered as a type of reactor, methods of kinetic analysis and reactor modeling from the viewpoint of chemical reaction engineering have not yet been established. The rate of an electrochemical reaction is a function of concentration, temperature, and interfacial potential difference (or electromotive force). This study examined the cathode reaction in a polymer electrolyte fuel cell, in which oxygen and protons react over platinum in the catalyst layer (CL). The effects of the oxygen partial pressure and the cathode electromotive force on the reaction rate were assessed. Resistance to proton transport increases the electromotive force and reducing the reaction rate. It was established that the effectiveness factor of the cathode CL is determined by competition between the reaction and mass transport of oxygen and protons. Two dimensionless moduli that govern the cathode behavior are proposed as a means of depicting the processes in the cell. © 2016 American Institute of Chemical Engineers AIChE J, 63: 249–256, 2017     

Magnetic field-assisted finishing for micropore X-ray focusing mirrors fabricated by deep reactive ion etching

A magnetic field-assisted finishing process has been studied for high-aspect-ratio ion-etched silicon curvilinear micropore structures, which have potential application as mirrors for satellite-borne X-ray telescopes. The micropore sidewalls act as X-ray focusing mirrors, and lead to reductions in the mass-to-effective-area ratio of 10-1000 times, compared to traditional X-ray telescopes. This paper describes the processing principle for the surface finishing of the sidewalls of micropore structures (10, 20 μm and depth: 300 μm (aspect ratio ≈ 15, 30)), and the feasibility of achieving roughness ∼4 nm rms and improving the X-ray reflectivity of micropore sidewall surface are demonstrated.     

Ab initio study on plane defects in zirconium–hydrogen solid solution and zirconium hydride

Hydrogen embrittlement of zirconium alloys is one of the main causes of the mechanical degradation of the fuel cladding in light water reactors, and has therefore been extensively studied. Although various conjectures have been proposed as the origin of such embrittlement, it is not known which one plays the most important role: the brittle nature of the hydride, micro-crack nucleation by interaction of hydride precipitates with dislocations or void nucleation at the interface between hydride precipitates and zirconium matrix. The purpose of the present study was to elucidate the origin of the embrittlement by investigating the fracture properties of the hydride. We have evaluated the surface energy γ_S and unstable stacking energy γ_US of Zr–H systems by using ab initio calculations. The ductile/brittle behavior of the hydride is discussed based on the difference between γ_S and γ_US among the hydride, pure zirconium and hydrogen solid solution. For the solid solution at a H/Zr ratio less than 0.5 we obtained a monotonous decrease by 15–34% and 50–100% in γ_S and γ_US, respectively, from those in pure zirconium, indicating a reduction in both brittleness and ductility. Thus, hydrogen-induced embrittlement of the hcp Zr matrix was not confirmed. On the other hand, for the hydride we obtained a 25% smaller γ_S and a 200–300% larger γ_US than those in pure zirconium. This indicates that zirconium hydride has an extremely brittle nature due to the synergistic effect of a small γ_S, implying easy generation of a fracture surface, and large γ_US, implying a difficulty in dislocation motion, compared with pure zirconium. Furthermore, Rice’s ductile/brittle parameter D was 1.4 in the δ-hydride, indicating that it undergoes brittle fracture more easily than iridium, known as an extremely brittle material. These results seem sufficient to attribute hydrogen embrittlement of zirconium alloys substantially to the brittle nature of the hydride.     

Time-resolved DXAFS study on the reduction processes of Cu cations in ZSM-5

The time-resolved reduction process of copper cations in/on ZSM-5 during temperature-programmed reduction (300–700 K) was studied by energy-dispersive X-ray absorption fine structure (DXAFS) as well as transmission electron microscopy (TEM). Two Cu-ZSM-5 samples with different Cu loadings were prepared by an ion-exchange method. The Cu K-edge DXAFS spectra for isolated Cu₂₊ species in the channels of ZSM-5 and CuO particles on the outer surfaces of ZSM-5 were recorded at an interval of 1 s during the reduction. The curve fitting analysis of the EXAFS data and the XANES analysis revealed that the isolated Cu₂₊ species in the channels were reduced stepwise. They were reduced to isolated Cu₊ species at 400–450 K and the Cu₊ species to Cu₀ metallic clusters at 550–650 K. Small clusters like Cu₄ were initially formed, followed by particle growth. A small part of them went out to the outer surfaces of ZSM-5 during the reduction. In contrast, CuO particles on the outer surfaces were reduced directly to Cu₀ metallic particles around 450 K.     

Design and Fabrication of a Novel Electrode-Supported Honeycomb SOFC

We report the design and fabrication of a novel electrode-supported honeycomb solid oxide fuel cell (SOFC), that can generate high volumetric power density. Among various cell designs, honeycomb SOFCs are suitable for compact SOFC modules because they have a large surface electrode area per unit volume. We have succeeded in fabricating a cathode-supported honeycomb SOFC via extrusion of a LaSrMnO₃ honeycomb monolith and through the use of a new slurry injection method for the channel surface coating using electrolyte/anode bi-layers. The fabricated honeycomb SOFCs exhibited high volumetric power densities of approximately 1.2 W/cm³ at 600°C under a wet H₂ fuel flow.     

Resistance Degradation in Y(Cr,Mn)O3–Y2O3 Composite NTC Ceramics in Hostile Environments

A series of composite, negative temperature coefficient (NTC) ceramics were carefully processed with compositions based on the Y(Cr,Mn)O₃+Y₂O₃ system and these were investigated for resistance stability in hostile environments. This specific system is of interest for high-temperature automobile thermistors, however either through the processing or in use of these, materials can be exposed to reducing atmospheres at temperatures around 900°–1000°C. The thermochemical processes at intermediate temperatures and low     <10⁻¹⁰atm can influence the resistance of the given ceramics. Through an impedance analysis it is determined that the resistance increase is associated primarily with a grain boundary resistance increase. The grain and grain boundary elements are modeled through parallel constant phase element and resistance equivalent circuits connected in series. Possible origins of the defect chemistry being controlled through high-temperature processes at the sintering are partial Schottky reactions that are compensated through a superoxidation reaction on cooling and aging. The reduction process reversed the superoxidation reaction and transited the grain boundary surfaces to ionically compensated B-site vacancies with oxygen vacancies.     

Processability and mechanical properties for binary blends of PP and LLDPE produced by metallocene catalyst

Processability at extrusion coating and mechanical properties of the films obtained are investigated by means of linear and nonlinear rheological measurements and tensile tests for blends of polypropylene (PP) and linear low‐density polyethylene (LLDPE). Both materials are produced by metallocene catalyst. The processability of PP is found to be improved by the addition of LLDPE; the blend shows low level of motor torque and head pressure in an extruder and small level of neck‐in as compared with pure PP. Further, the anisotropy of ultimate tensile strength, which is prominent for PP, is reduced by blending with LLDPE. As a result, the blend having 20 wt % of LLDPE shows appropriate properties in the molten state for extrusion coating and in the solid state as a film. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Photocatalytic decomposition of 2-propanol in air by mechanical mixtures of TiO2 crystalline particles and silicalite adsorbent: The complete conversion of organic molecules strongly adsorbed within zeolitic channels

Fundamental photocatalytic behaviors were investigated for mechanical mixtures of TiO₂ crystalline particles (P25) and MFI type zeolite (silicalite) in the decomposition reaction of 2-propanol vapor in air for the first time. Mechanical mixing enables reliable comparisons to be made between photocatalysts because the contents of TiO₂ and the adsorbent can be widely varied (51 times in this study) while keeping the particle size and crystallinity of TiO₂ unchanged. That is, the use of mechanical mixture highlights the behavior of molecules adsorbed in the microporous crystals, keeping the TiO₂ unchanged. In the case of the mixed photocatalysts, the initial 2-propanol concentration in the gas phase was significantly reduced because of adsorption into the zeolite. After photo-irradiation started, 2-propanol was decomposed to CO₂ with no (or trace amount of) acetone detected in the gas phase. The analysis of final amount of CO₂ formed by the decomposition demonstrated that just by the mechanical mixing of TiO₂ and zeolite, the TiO₂ photocatalyst decomposed completely the reactant and intermediate molecules strongly adsorbed into the zeolite. On the other hand, in reference experiments in which TiO₂ and zeolite were not mixed and were separately placed in a photoreactor, the organic compounds strongly adsorbed in the zeolite could not be decomposed to CO₂ by the photocatalyst. It is notable that the CO₂ formation rates for the mixed photocatalysts were mostly constant for those comprising 40 wt% or larger amounts of zeolite, while being slower than for pure TiO₂. The rate-determining step was discussed based on these data. The present study showed that the mixed photocatalyst could remove organic vapors by adsorption in the dark and decompose completely to CO₂ at moderate reaction rates under photo-irradiation with minimized evolution of intermediate molecules into the gas phase.