Gas discrimination method for detecting transformer faults by neural network

This paper describes a method available for early detection of abnormality in an oil-filled transformer. In this method, four gas sensors having different characteristics and neural network are used to identify gas species (H₂, CH₄, C₂H₄, C₂H₂ and mixture of two species). To improve the selectivity of gas sensors, the time response patterns induced by changing sensor temperature and the stationary sensor output are identified by neural network. Furthermore, the mixture ratio of gases is derived by using the stationary sensor output in response to the changing sensor temperature. Gas species are well discriminated, and the mixture ratio derived from the sensor output agrees well with the measurement by gas chromatography. Therefore, it is confirmed that our method is applicable to the transformer diagnostic technology.     

Molecular motion in poly(amino acid)s: 7. Molecular motion in the β-form crystal of silk fibre

Molecular motion in the β-form crystal of fully annealed silk fibre was investigated by means of an X-ray diffractometer, an infra-red spectrophotometer, and thermal and viscoelastic measurements. There was ordinary thermal expansion in stable sheets up to 250°C, in which chains were bound side by side with intermolecular hydrogen bonds. It was shown that the slip motion between the sheets started at about 200°C, accompanied by active motion and/or slight scission of the side chains packed in the intersheets. Melting of the crystal occurred due to scission of the intermolecular hydrogen bonds above 260°C in the sheets. Melting was accompanied by degradation of the molecular chains.     

Thermal properties of ionomer

A series of resol-type phenol-formaldehyde resins with varying phenol/formaldehyde (P/F) molar ratio were investigated by infrared spectroscopy. The infrared spectroscopic data suggest that absorbance ratio of D₂₉₂₀, D₁₆₁₀, D₁₁₅₀, D₁₀₁₀, and D₇₆₀ based on 1 590 cm^?1 band can be used for the determination of phenol/formaldehyde molar ratio of the resins.     

Vinyl polymerization by metal complexes. V. Effects of amines on the polymerization by copper(II) chelate and carbon tetrachloride initiating system

The polymerization of acrylonitrile was studied by the system of copper(II)-oligo(n)ethylene-(n+1)amine complex and carbon tetrachloride. Addition of amines to the initiating system accelerates the polymerization. The acceleration by these amines was found to be in the following order: prim.-amine<sec.-amine<tert.-amine<diamine<phenylenediamine. Effects of the sort of the ligands in the copper(II) chelates on the polymerization were also studied.     

Human Behavior in Residential Moving

Behaviormetrika - Apartment dwellers move more and more frequently in recent years. Motives of the move are job transfer, change for better housing, and marriage. The desire for change is the...     

E-cadherin gene-engineered feeder systems for supporting undifferentiated growth of mouse embryonic stem cells

Conventionally, embryonic stem (ES) cells are cultured on a cell layer of mouse embryonic fibroblasts (MEFs) as feeder cells to support undifferentiated growth of ES cells. In this study, cell–cell interactions between mouse ES and feeder cells were artificially engineered via an epithelial cell adhesion molecule, E-cadherin, whose expression is considerable in ES cells. Mouse mesenchymal STO and NIH3T3 cells that were genetically engineered to express E-cadherin were used in ES cell cultures as feeder cells. ES cells cultured on the E-cadherin-expressing feeder cells maintained the expression of stem cell markers, alkaline phosphatase (AP), Oct3/4, Nanog and Sox2, and the efficiency of AP-positive colony formation was comparable to MEFs, and much better than parental STO and NIH3T3 cells. Furthermore, ES cells maintained on the E-cadherin-expressing feeder cells possessed the ability to differentiate into the three germ layers both in vitro and in vivo. The results indicated that E-cadherin expression in feeder cells could improve the performance of feeder cells, which may be further applicable to create new artificial feeder cell lines.     

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.     

Application of Ni-free high nitrogen stainless steel for bipolar plates of proton exchange membrane fuel cells

Ni-free 23Cr-1N stainless steel was examined as bipolar plates for proton exchange membrane fuel cells. Corrosion resistance of the 23Cr-1N stainless steel was better relative to 22Cr stainless steel in the simulated cathodic environments. As confirmed by X-ray photoelectron spectroscopy, the polarized 22Cr and 23Cr-1N stainless steels at pH 2.3 presented predominantly chromium oxide in the outer passive layers. At pH 4.3, the passive layer of the polarized 22Cr stainless steel changed to iron oxides dominant. Interestingly, on the other hand, the polarized 23Cr-1N stainless steel preserved chromium oxide rich outer passive layer, which provides good corrosion resistance. As a result, although the initial cell voltage was slightly lower (∼40 mV), the 23Cr-1N stainless steel bipolar plates employing cell showed better cell voltage stability up to 1000 h, compared with the 22Cr stainless steel employing cell. The operation voltage became further higher through a surface modification of the 23Cr-1N stainless steel with TiN nanoparticles. It seems that the corrosion resistive Ni-free 23Cr-1N is possible to apply for bipolar plates of proton exchange membrane fuel cells.