Transient analysis of blowdown thrust force under PWR LOCA

The analytical results of blowdown characteristics and thrust forces were compared with the experiments, which were performed as pipe whip and jet discharge tests under the PWR LOCA conditions. The blowdown thrust forces were obtained by Navier-Stokes momentum equation for a single-phase, homogeneous and separated two-phase flow, assuming critical pressure at the exit if a crifical flow condition was satisfied.The following results are obtained:

1. (1) The node-junction method is useful for both the analyses of the blowdown thrust force and of the water hammer phenomena.

2. (2) The Henry-Fauske model for subcooled critical flow is effective for the analysis of the maximum thrust force under the PWR LOCA conditions. The jet thrust parameter of the analysis and experiment is equal to 1.08.

3. (3) The thrust parameter of saturated blowdown has the same one with the value under pressurized condition when the stagnant pressure is chosen as the saturated one.

4. (4) The dominant terms of the blowdown thrust force in the momentum equation are the pressure and momentum terms except that the acceleration term has large contribution only just after the break.

A comparative study of fracture behavior between carbon black/poly(ethylene terephthalate) and multiwalled carbon nanotube/poly(ethylene terephthalate) composite films

Fracture behavior of amorphous poly(ethylene terephthalate) (PET) films added multiwalled carbon nanotube (MWCNT) has been compared with that of the PET films added with carbon black (CB) to elucidate the effects of the large aspect ratio of MWCNT. Fracture toughness has been evaluated using the essential work of fracture tests. Evolution of the crazes has been analyzed by conducting time‐resolved small‐angle X‐ray scattering measurements during tensile deformation of the films at room temperature using synchrotron radiation. CB and MWCNT increased the fracture toughness of the PET film by increasing the plastic work of fracture. This resulted from the effects of the fillers to prevent the localization of deformation upon the crazes formed at earlier stages of tensile deformation and to retard the growth of the fibrils in the crazes to a critical length. The CB particles provided a number of sites where the crazes were preferably formed due to stress concentration. In the case of MWCNT, on the other hand, the widening of the crazes formed at earlier stages was suppressed due to the bridging effect arising from the large aspect ratio of MWCNT. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

High performance electron negative resist,chloromethylated polystyrene. A study on molecular parameters

High sensitivity and high contrast electron negative resist, chloromethylated polystyrene (CMS) was developed for direct writing electron beam lithography with 1-μm resolution. The resist shows excellent lithographic performances such as high plasma-etching durability and negligible “post polymerization effect”. A series of CMS covering a wide range of M?_w, 6,800–560,000, were synthesized by the chloromethylation of nearly monodisperse polystyrenes. The effects of molecular parameters on sensitivity and resolution were investigated. The chloromethylation remarkably improved the reactivity of polystyrene, but which was saturated above 40% of chloromethylation ratio. About 100 times higher sensitivity could be achieved as compared with the starting material. As the increase of chloromethylation ratio (CR) gradually broadened the molecular weight distribution (MWD), the optimum CR was evaluated to be about 40%. In the above range of M?_w, the sensitivity varies from 39 to 0.4 μC/cm, whereas the γ-value varies from 3.0 to 1.4. A sharp edge profile was obtained in developed pattern of CMS resist because of its relatively high glass-transition temperature (68–115°C) compared with commercial resists and the suitable selection of a developer. The resolution of CMS was compared with the structually related polymers synthesized from polystyrene with a broader MWD or vinylbenzylchloride and poly(chloroethylvinylether) (CEVE). These polymers show significantly lower resolution than CMS, which indicates the importance of MWD and T_g in electron negative resist.     

Transmission analysis of electromagnetic induction RFID system

The transmission characteristics of the electromagnetic induction RFID systems are greatly influenced by the distance between the primary and secondary antenna coils and by the materials used in their design. In this paper the induced current of the secondary antenna coil is calculated by the 3D finite element method when both the primary and secondary antenna coils are operated in resonant circuits. The influences of the analyzed parameters on the transmission characteristics are demonstrated. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(4): 38–45, 2010; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21019     

Development of Lignin-Based Terpolyester Film and Its Application to Separator Material for Electric Double-Layer Capacitor

For new application of technical lignins as separator material for electric double-layer capacitor (EDLC), we tried first to prepare bipolyester film by melt-polycondensation of polyethylene glycol lignin (PEGL) and maleic anhydride. The EDLC assembled with this film, however, showed lower electrochemical performance than the reference EDLC with commercial cellulosic separator. Porous bipolyester film was then prepared and the resulting EDLC exhibited improved specific capacitance, but high intrinsic and charge transfer resistances. Non-porous terpolyester film was prepared next, using polyethylene glycol 500,000 to improve flexibility of the film, which might lower the resistances. This film was flexible enough and provided the resulting EDLC with superior electrochemical performance to the bipolyester film. EDLC with porous terpolyester film was finally prepared and showed the highest electrochemical performance, comparable to the reference EDLC. Porous morphology and flexibility were key factors to fabricate lignin-based self-standing film as separator material for high-performance EDLC.     

The Traveling Agent Problem

 This paper considers a sequencing problem which arises naturally in the scheduling of software agents. We are given n sites at which a certain task might be successfully performed. The probability of success is p _i at the ith site and these probabilities are independent. Visiting site i and trying the task there requires time (or some other cost metric) t _i whether successful or not. Latencies between sites i and j are l _ij, that is, the travel time between those two sites. Should the task be successfully completed at a site then any remaining sites do not need to be visited. The Traveling Agent Problem is to find the sequence which minimizes the expected time to complete the task. The general formulation of this problem is NP-Complete. However, if the latencies are constant we show that the problem can be solved in polynomial time by sorting the ratios t _i/p _i according to increasing value and visiting the sites in that order. This result then leads to an efficient algorithm when groups of sites form subnets in which latencies within a subnet are constant but can vary across subnets. We also study the case when there are deadlines for solving the problem in which case the goal is to maximize probability of success subject to satisfying the deadlines. Applications to mobile and intelligent agents are described. Date received: February 10, 1998. Date revised: November 16, 1999.     

Fine tuning of frontier orbital energy levels in dithieno[3,2-b:2′,3′-d]silole-based copolymers based on the substituent effect of phenyl pendants

A series of dithieno[3,2-b:2′,3′-d]silole-based π-conjugated copolymers containing thieno[3,4-c]pyrrole-4,6-dione or thieno[3,4-b]thiophene units bearing 4-substituted phenyl pendants were synthesized and their thermal stability, optical properties and frontier orbital energy levels were systematically investigated. The introduction of electron-withdrawing substituents on the phenyl rings lowered their frontier orbital energy levels without deteriorating their thermal and optical properties. By replacing an electron-donating methoxy group with an electron-withdrawing trifluoromethyl group, both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital energy levels of the polymers were deepened by more than 0.3 eV. A relatively linear relationship was observed between the HOMO energy levels and the Hammett substituent constants.     

Nitric oxide-scavenging compounds in Agrimonia pilosa Ledeb on LPS-induced RAW264.7 macrophages

The extract of Agrimonia pilosa Ledeb, with a high polyphenol content, inhibited nitrite accumulation as an indicator of nitric oxide (NO) in LPS-induced RAW264.7 macrophages. The NO inhibitory compounds in the extract were isolated using open column chromatography and HPLC, and five phenolic compounds, namely aromadendrin (AD), dihydrokaempferol 3-O-β-D-glucoside (DK3-O-glc), quercitrin (QC), aglimonolide-6-O-β-D-glucoside (AG6-O-glc) and loliolide (LL), were determined by ¹H, ¹³C NMR and LC/MS analyses. This is the first time that these compounds have been isolated from this plant. 4-Ethyl-2-hydroxyamino-5-nitro-3-hexenamide (NOR3), as a NO donor, was used in the presence of these compounds and then the nitrite-level, as an index of NO, decreased, indicating that these compounds would potentially have a NO-scavenging activity. An ESR study of the system containing NOR3 and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), as a NO detection reagent, with or without the compound, provided the evidence that these compounds directly scavenged NO and the scavenging activities of three flavonoids (AD, DK3-O-glc and QC) were remarkably high in comparison to those of the other phenolic compounds. These results indicated that one of the suppression mechanisms in cells would be the NO-scavenge of phenolic compounds.     

A method for production of γ-amino butyric acid (GABA) using barley bran supplemented with glutamate

γ-amino butyric acid (GABA) has antihypertensive and anti-stress effects on human health. In this study, we developed a simple method for GABA production from sodium glutamate using barley bran without any buffer or any coenzyme. We determined the optimal reaction conditions of the GABA production using barley bran as described below, reaction temperature: 20 °C, initial barley bran concentration: 150 mg/mL, initial sodium glutamate concentration: 10 mM, reaction time: 6 h. Under optimal conditions using barley bran, the concentration of GABA reached 11.0 mM (containing GABA from barley bran) from 10.0 mM of sodium glutamate; however in using wheat and rice bran, the GABA concentrations were only 3.9 and 0.8 mM, respectively. To apply the water containing GABA produced from sodium glutamate using barley bran (WGBB) to beer brewing, we prepared wort using WGBB. The wort contained a large amount of GABA (257 μg/mL) without lowering the other wort qualities.     

Mixed P3HT/PCBM Organic Thin-Film Transistors： Relation between Morphology and Electrical Characteristics

The mixed P3HT （poly（3-hexylthiophene）） and [6,6]-PCBM （phenyl C61-butyric acid methyl ester） organic thin films were investigated for electronic structure using UV-Vis spectrophotometer and PESA （photo-electron spectroscopy in air）. Furthermore, ESR （electron spin resonance） and AFM （atomic force microscopy） were used to investigate the surface morphology and molecular orientation, respectively. ESR analysis indicated the molecular orientation of the P3HT crystalline in the blend thin films, which the crystalline oriented normal to the substrate with distribution of 35°. AFM images indicated that the surface morphology of P3HT film was affected by the presence of PCBM nanoparticles. Solution-processed OTFTs （organic thin-film transistors） based on P3HT/PCBM blend thin film in a top source-drain contact structure was fabricated, and the electrical characteristics of the devices were also investigated. A unipolar property with p-channel characteristics were obtained in glove box measurement.