Application of magneto-optical sensors for fault location in an air-insulated substation bus

A new fault location system using optical current transducers (CTs) to detect faulted sections in the bus bars of directly grounded 275-kV substations has been developed. This system detects fault current by combining optical CTs with wound-type CTs. The new type of optical CT applies a bulk-type Faraday sensor to the combination of windings around a magnetic iron core and a solenoid coil. The optical CT was capable of current measuring over 50 kA. A current differential discriminator combining an optical CT and a wound-type CT verified the operational performance with 40-kA currents. The intended level of fault detection performance was obtained. Based on these results, a system is being made for actual application in 275-kV substations. © 1997 Scripta Technica, Inc. Electr Eng Jpn 119(2): 10–17, 1997     

Cytokine Networks in the Pathogenesis of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic systemic inflammation causing progressive joint damage that can lead to lifelong disability. The pathogenesis of RA involves a complex network of various cytokines and cells that trigger synovial cell proliferation and cause damage to both cartilage and bone. Involvement of the cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6 is central to the pathogenesis of RA, but recent research has revealed that other cytokines such as IL-7, IL-17, IL-21, IL-23, granulocyte macrophage colony-stimulating factor (GM-CSF), IL-1β, IL-18, IL-33, and IL-2 also play a role. Clarification of RA pathology has led to the development of therapeutic agents such as biological disease-modifying anti-rheumatic drugs (DMARDs) and Janus kinase (JAK) inhibitors, and further details of the immunological background to RA are emerging. This review covers existing knowledge regarding the roles of cytokines, related immune cells and the immune system in RA, manipulation of which may offer the potential for even safer and more effective treatments in the future.     

Preparation and mechanical properties of polystyrene–clay hybrids

Polystyrene–clay hybrids (PSCHs) were prepared by melt blending a styrene vinyloxazoline copolymer with organophilic clay. In the PSCHs, the silicate layers of the clay were delaminated and dispersed homogeneously to the nanometer level. The moduli of the PSCHs were higher than that of the PS copolymer. For example, the tensile modulus of the PSCH with 5 wt % clay was 1.4 times higher compared to that of the PS copolymer. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3359–3364, 1999     

Evaluation of immunochromatographic test kits for food allergens using processed food models

It has been mandatory to label five allergenic substances (AS; egg, milk, wheat, buckwheat and peanut) in all processed foods, since April 2002 in Japan. Two kinds of ELISA kits have been provided as screening test kits for the Japanese official method. The kits have many advantages but some disadvantages, i.e., the kits are not necessarily suitable for daily monitoring in food manufacturing plants, because they require various analytical equipments and the use of complicated procedures. To overcome these drawbacks, we have developed other diagnostic kits based on immunochromatography that should enable more rapid and simple screening for food allergens. Then we examined the performance of these immunochromatographic test kits (IC kits) in terms of sensitivity, repeatability and cross-reactivity to AS proteins in 11 kinds of food models with various heating conditions and physical properties. We also examined processed food models including AS protein of constant concentration, using the IC kits and ELISA kits, and compared the results. The IC kits detected AS proteins at 5 microg/g in the extracts from processed food models, and provided highly reproducible results. Cross-reactivity among the AS proteins was not observed. The results obtained using the IC kits showed performance equivalent to that of the ELISA kits we examined in unheating processed food models including AS proteins of constant concentration. The IC kits should be more suitable for daily monitoring in food manufacturing plants.     

Estimation of heat generation rate in solid oxide fuel cell module from single cell performance and module performance based on impedance analysis

Heat generation rate in SOFC module was estimated under various thermal self-sustained conditions. SOFC module and system was designed to evaluate power generation property and temperature of module. Single cell was also evaluated the performance and electrode overpotential by impedance analysis under the similar condition to module power generation state. We estimated the heat generation rate with enthalpy calculation based on the actual module performance, and also with entropy calculation based on the impedance analysis of single cell. It was found that the heat generation rate calculated by enthalpy is approximately corresponded with that calculated by entropy. There still contains small error between heat generation rate calculated by enthalpy and that calculated by entropy. It was considered that these errors are originated from distribution in stack temperature and reforming gas temperature in the module. According to impedance analysis, it was found that the ohmic resistance is varied under operating condition and related with the current distribution which is calculated with the current path length in the cell. It was suggested that power generation state of module is affected by the current path length in the cell (in another word, distribution of power density) and distribution of overpotential; these phenomena is dominated by gas composition and thermal self-sustainable temperature.     

Electrochemical properties of LiPON films made from a mixed powder target of Li3PO4 and Li2O

Lithium phosphorus oxynitride (LiPON) films were prepared by radio frequency magnetron sputtering. In order to control the atomic composition of the films, a mixture of Li₃PO₄ and Li₂O powders was used as the sputtering target. The ionic conductivity of the films showed a maximum (6.4 × 10^− 6 S/cm) when the molar ratio of Li₃PO₄ to Li₂O in the target was 1:2. The films formed from a target not containing Li₂O showed good durability in air at the expense of slightly poorer ionic conductivity. This is probably due to the amount of Li in the film being significantly less which effectively suppressed absorption of CO₂ in air.     

Mechanical properties of Si nanowires as revealed by in situ transmission electron microscopy and molecular dynamics simulations

Deformation and fracture mechanisms of ultrathin Si nanowires (NWs), with diameters of down to ~9 nm, under uniaxial tension and bending were investigated by using in situ transmission electron microscopy and molecular dynamics simulations. It was revealed that the mechanical behavior of Si NWs had been closely related to the wire diameter, loading conditions, and stress states. Under tension, Si NWs deformed elastically until abrupt brittle fracture. The tensile strength showed a clear size dependence, and the greatest strength was up to 11.3 GPa. In contrast, under bending, the Si NWs demonstrated considerable plasticity. Under a bending strain of <14%, they could repeatedly be bent without cracking along with a crystalline-to-amorphous phase transition. Under a larger strain of >20%, the cracks nucleated on the tensed side and propagated from the wire surface, whereas on the compressed side a plastic deformation took place because of dislocation activities and an amorphous transition.     

Electronic structure of the buried interface between an organic semiconductor, N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD), and metal surfaces

The electronic structures of buried interfaces between an organic semiconductor, N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) and metal surfaces of Au, Ag, Al and Ca were examined by the new experimental method that we have developed recently. In this method the energy levels at the organic/metal interface can be examined without changing the film thickness and related physical parameters e.g., the vacuum levels of the sample in contrast to the widely-used thickness-dependent photoemission experiments. The results were discussed in view of large interfacial dipole moment of the TPD and metal (Au and Ag) contacts.     

An ultra-fast fabrication technique for anode support solid oxide fuel cells by microwave

An effective and facile technique has been developed for high temperature anode-electrolyte co-sintering of anode support solid oxide fuel cells by using microwave activated sparking plasma. A high sintering temperature of 1600 °C can be achieved in a few minutes time by discharging effect. Anode support substrate pellet is uniaxially pressed, and then dip-coated with a 10 μm yttria stabilized zirconia electrolyte layer. After the microwave co-sintering, La_0.8Sr_0.2MnO_x cathode is screen-printed onto electrolyte and sintered by conventional thermal method. The cell has stably operated in 3% humidified hydrogen for more than 130 h.     

Growth of ZnO crystal on sapphire and nitridated sapphire substrates at 1000 °C by halide vapor phase epitaxy

Using a halide vapor phase epitaxy (HVPE) technique in which the starting materials are ZnCl₂ generated by the reaction between high purity Zn metal (7 N grade) and Cl₂ gas, and H₂O, ZnO crystals have been grown at a high temperature of 1000 °C on sapphire substrates with and without surface nitridation treatment. It was found that the nitridation treatment resulted in a change of the (112?0) sapphire surface to a (0001) AlN structure, leading to two possible sets of orientations for (0001) ZnO crystals. In addition, the nitridation treatment leads to a smaller average ZnO grain size and a higher density of nuclei.