Pulsed field losses and coupling current loop in a large‐current superconductor

Pulsed field losses in a short sample (445 mm length) of 46‐kA Nb₃Sn cable‐in‐conduit conductor of superconducting magnet for the fusion experimental reactor “ITER” are measured by a calorimetric method. The coupling time constant between strands is obtained as 30 ms through pulsed loss. Based on this time constant and interstrand conductance measurement, it is expected that there is a coupling current loop length of about 400 mm, which is longer than half the fabrication twist pitch in the fourth cabling stage. A geometrical calculation on several‐stage cabling shows this value to be reasonable. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 142(4): 27–33, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10088     

Variations in the soluble sugar and organic acid contents in radish (Raphanus sativus L.) cultivars

The radish is a root vegetable of the Brassicaceae family that is mainly consumed in Far Eastern Asian countries. Because chemical indexes indicating the quality of a radish have not been established, we investigated the variations in the contents of the soluble sugars and organic acids that influence taste among seven radish cultivars. In terms of the total soluble sugar content, which is a strong index of sweetness, Koshin, Kouto, and Shogoin were the three highest among the seven cultivars. Sobutori, which is the most common radish cultivar in Japan, was the lowest. The total organic acid contents varied among the seven cultivars, although they were five to thirteen times lower than the total soluble sugar contents. These results indicate that there are variations in the soluble sugar and organic acid contents among radish cultivars; therefore, these contents may be used as chemical indexes for the quality of radishes.     

Real-time dynamics of prostaglandin F2alpha release from uterus and corpus luteum during spontaneous luteolysis in the cow

Prostaglandin (PG) F2alpha released from the uterus in a pulsatile fashion is essential to induce regression of the corpus luteum (CL) in the cow. In addition to the uterus, the CL has also been recognized as a site of PGF(2alpha) production. Therefore, this study aimed to determine the detailed dynamics of the releasing profile of CL-derived PGF2alpha together with uterus-derived PGF2alpha during spontaneous luteolysis in the cow. Non-lactating Holstein cows (n = 6) were surgically implanted with a microdialysis system (MDS) on day 15 (oestrus = day 0) of the oestrous cycle. Simultaneously, catheters were implanted to collect ovarian venous plasma ipsilateral to the CL as well as jugular venous plasma. The concentrations of PGF2alpha, 13,14-dihydro-15-keto-PGF2alpha (PGFM) and progesterone in the MDS and plasma samples were determined by enzyme immunoassays. The intra-luteal PGF2alpha secretion slightly increased after the onset of luteolysis (0 h) and drastically increased from 24 h, and was maintained at high levels towards the following oestrus. Furthermore, PGF2alpha was released from the CL into the ovarian vein in a pulsatile manner during spontaneous luteolysis. Also, the fact that intra-luteal secretion of PGF2alpha and PGFM showed a positive correlation indicates the existence of a local metabolic pathway for PGF2alpha in the CL. In conclusion, the present study clarified the real-time dynamics of uterus-derived PGF2alpha and CL-derived PGF2alpha during spontaneous luteolysis in the cow, and gives the first in vivo evidence that the CL releases PGF2alpha during spontaneous luteolysis in the cow. Although the physiological relevance of CL-derived PGF2alpha appears to be restricted to a local role as an autocrine/paracrine factor in the CL, overall results support the concept that the local release of PGF2alpha within the regressing CL amplifies the luteolytic action of PGF2alpha from the uterus.     

Effect of amplification of desensitized purF and prs on inosine accumulation in Escherichia coli

The effect of a phosphoribosylpyrophosphate (PRPP) synthetase gene (prs) that was desensitized to feedback inhibition by ADP on inosine accumulation was investigated using an inosine-producing mutant of Escherichia coli. At the same time, various types of plasmid having a PRPP amidotransferase gene (purF) that was desensitized to feedback inhibition by AMP and GMP were also investigated to improve inosine productivity using a compatible plasmid containing prs with a plasmid containing purF. The recombinant E. coli I-9 harboring a low-copy-number plasmid having the desensitized-purF (pMWKQ) accumulated 3.6 g/l inosine from 40 g/l glucose in a 2-d culture. Furthermore, desensitized-prs amplification, in addition to purF, resulted in the accumulation of 6.2 g/l inosine. Additionally, through these experiments, a spontaneous mutant with an enhanced inosine-producing ability compared with the parent strain I-9 was obtained. The spontaneous mutant I-9m harboring only pMWKQ and I-9m harboring both pMWKQ and pSTVDA (a plasmid having the desensitized-prs) accumulated 6.7 g/l and 7.5 g/l inosine, respectively, from 40 g/l glucose in a 3-d culture.     

A review of current anti-islanding methods for photovoltaic power system

Islanding phenomenon is undesirable because it leads to a safety hazard to utility service personnel and may cause damage to power generation and power supply facilities as a result of unsynchronized re-closure. Until now, various anti-islanding methods (AIMs) for detecting and preventing islanding of photovoltaic and other distributed generations (DGs) have been proposed. This paper presents an overview of recent anti-islanding method developments for grid-connected photovoltaic (PV) power generation, focusing on the concept and operating principle, mainly based on single phase system. For the performance comparison, the experimental results of the various AIMs with 3 kW PV inverter are provided based on the islanding detection capability and power quality. As a result, the active AIMs have better islanding detection capability rather than the passive one. However, the active AIMs have power quality degradation on harmonic distortion or displacement power factor based on the injected active signal type. In addition to the evaluation and comparison of the main anti-islanding methods, this paper also summarizes the related anti-islanding standards to evaluate anti-islanding capability for PV system. This paper can be used as a useful anti-islanding reference for future work in DG like PV, and wind turbine.     

Hydrogen and ethanol production from glycerol-containing wastes discharged after biodiesel manufacturing process

H2 and ethanol production from glycerol-containing wastes discharged after a manufacturing process for biodiesel fuel (biodiesel wastes) using Enterobacter aerogenes HU-101 was evaluated. The biodiesel wastes should be diluted with a synthetic medium to increase the rate of glycerol utilization and the addition of yeast extract and tryptone to the synthetic medium accelerated the production of H2 and ethanol. The yields of H2 and ethanol decreased with an increase in the concentrations of biodiesel wastes and commercially available glycerol (pure glycerol). Furthermore, the rates of H2 and ethanol production from biodiesel wastes were much lower than those at the same concentration of pure glycerol, partially due to a high salt content in the wastes. In continuous culture with a packed-bed reactor using self-immobilized cells, the maximum rate of H2 production from pure glycerol was 80 mmol/l/h yielding ethanol at 0.8 mol/mol-glycerol, while that from biodiesel wastes was only 30 mmol/l/h. However, using porous ceramics as a support material to fix cells in the reactor, the maximum H2 production rate from biodiesel wastes reached 63 mmol/l/h obtaining an ethanol yield of 0.85 mol/mol-glycerol.     

Sensitization effect by porphyrin in polythiophene/perylene dye two-layer solar cells

An enhanced photocurrent was observed for a two-layer cell consisting of a regioregular polythiophene (PTh) blended with metal-free porphyrin (H₂tpp) and a perylene tetracarboxylic derivative (PV), compared to a PTh (without H₂tpp)/PV two-layer cell. This is because photoexcited H₂tpp molecules efficiently transfer holes to PTh molecules and then produced electrons in H₂tpp molecules rapidly transfer to PV molecules at the mixed solid/PV interface. In the two-layer photocell with the mixed solid, H₂tpp behaves as a sensitizer, PTh and PV solids as carrier transport layers, and the mixed solid/PV interface as a charge separation site. Power conversion efficiency attained to η=2.9% for the PTh (with H₂tpp)/PV two-layer cell under monochromatic light with 6 μW cm⁻² intensity.     

Improvement of wastewater treatment performance of the Fukashiba treatment plant.

The Fukashiba Treatment Plant Kashima Rinkai Specified Sewage Works has received wastewater from the petrochemical complex (90%) and public sewage of Kamisu and Hasaki town (10%). For this reason, the plant is facing many difficulties in producing good quality effluent. In order to solve these difficulties, we are reviewing the treatment performance and making efforts for its improvement with nitrification inhibition, control of bio-persistent substances and the PRTR approach.     

Single-pass desalination of high salinity sea water with reverse osmosis

Two types of new “HOLLOSEP” have been developed for single-pass desalination of high salinity seawater. One is a high pressure and high temperature module, type “HPT”. The performance of this new type HOLLOSEP is analyzed in the case of desalination of high salinity seawater under a high pressure Of 75Kg/cm² G at high temperature of 40°C. It has been found that the operation costs can be reduced by this high pressure and high temperature operation system.The other is a large size module containing five elements of 12 inches diameter, type “JM-12”. This module has been developed to reduce the water cost by enlarging the diameter and the length of a vessel coupled with the improvement in water flux rate of the hollow fiber membranes. The fresh water productivity of this module is 150m³/day under the conditions of 3.5% NaCl feed water, 30% product water recovery at 55kg/cm²G.