Microbial Sensors for the Detection of Fish Freshness

A microbial sensor system consisting of immobilized living spoilage-causing bacterium, Alteromonas putrefaciens, and an oxygen electrode was prepared and applied to the continuous determination of fish freshness. Fish freshness was expressed as a ratio of A/B, where A is the current decrease of the microbial sensor obtained by the application of l0–50 μL fish extract and B is the current decrease by the equivalent volume of culture medium. Freshness of bluefin tuna and yellowtail meats stored in ice for up to 2 weeks was determined by both the proposed and the conventional K value enzyme sensor method. Good comparative results were obtained. One assay could be completed within 13 min.     

二垩英与资源回收-Ⅰ考虑到二垩英生成的资源与能量回收基础研究

目前在日本,存在大量工业垃圾,包括各种塑料制品,ASR(汽车破碎垃圾),含有毒PCB(多氯联苯)的110变压器和PVC(聚氯乙稀)制品等.而来自城市垃圾焚烧炉的废气含有大量能量.因此,在充分考虑环境、避免二垩英生成的同时,安全回收来自工业垃圾、城市和/或工业垃圾焚烧炉的资源和能量是个非常重要的课题,这也将对抑制CO2排放作出贡献.正确地阐明焚烧过程中二垩英的生成机理及详细研究含少量二垩英的焚烧废气在冷却过程中大量形成二垩英的临界温度是项很重要的工作.解决这个问题可有效实现资源和能量的回收.本报告介绍日本在二垩英排放方面目前采取的对策和存在的问题以及大阪大学为阻止二垩英生成所做的基础研究工作.     

Development of magnesium composite alloy by a new method combining B2O3 addition and melt stirring

For developing high performance magnesium alloys, a new method in combination of B2O3 addition and melt stirring was applied. When 0.3%, 6% and 12%（ mass fraction） B2O3 was added into pure Mg, many twins were produced in each alloy. The average grain size of Mg was about 200 μm. In Mg-6Al alloy, the grain size is decreased from 50 to 35 μm by B2O3 addition. In Mg-6RE （rare earth） alloys, the grain size is decreased from 35 to 15 μm. The grain size of Mg-9Al- 6Ti-3B2O3 alloy is about 5 μm. The hardness of pure Mg does not change by B2O3 addition. In Mg-6Al alloy, the hardness is increased by addition of 3% B2O3, however, the hardness of Mg-6RE alloy is decreased by B2O3 addition. Addition of B2O3 into Mg-Al, Mg-RE and Mg-Al-Ti alloys makes the fine grain structures, the hardness of Mg-RE alloy is decreased. This strange behavior may be interpreted with existence of many fine pores in the alloy. The mechanical properties of composite Mg-9Al-6Ti with 3?O3 are higher than those of AZ91C. The present results demonstrate the potential of this new method for developing high performance magnesium alloys.     

Evaluation Results of the Signal Decomposition Technique for OFDM Transmission which Achieves the Power‐Added Efficiency Improvement and the SNR Enhancement Using the Noise Elimination

The authors have proposed the signal decomposition technique as one of the powerful solution to mitigate the large peak‐to‐average power ratio (PAPR) to be addressed in orthogonal frequency division multiplexing (OFDM) transmitters especially on mobile terminals. In order to enhance the receiver SNR, the simple noise elimination techniques working together with the signal decomposition technique have also been proposed that eliminates the noise added on the decomposed constant amplitude on‐off‐signals taking advantage of the knowledge of their constant amplitude at the receiver. In this paper, we discuss the parameter design issue of the proposed techniques and their optimization. Then, demonstrate the PAPR, the power‐added efficiency (PAE), and also the BER performances operating on the optimized parameters. It is confirmed that the proposed signal decomposition technique improves the PAPR by 4 dB and doubles the PAE at the complementary cumulative distribution function of 1%. It is also confirmed that the proposed noise elimination technique improves the receiver SNR by 3 dB at the BER of 10 to 3, which is nearly equal to that of conventional OFDM, under the conditions that the decomposed signals are transmitted over the independent additive white Gaussian noise channels. Furthermore, it is demonstrated that the proposed techniques work properly when the decomposed signals are transmitted over 2 × 2 multi‐input multi‐output.     

Comment on the equivalence condition of optimal control problems

Given a general non-linear plant, a method is presented for designing model reference feedback controllers for the plant. It is shown that the feedback controllers produced will guarantee prespecified closed-loop properties if the error between the plant and model lies within computable bounds. In particular, an upper bound on the tracking error is established and conditions are given that ensure closed-loop stability.     

Diagnosis Criterion of Abnormality of Transformer Winding by Frequency Response Analysis (FRA)

Frequency response analysis (FRA) is a powerful technique to detect internal abnormalities within power transformers. However, diagnosis criteria of power transformers by FRA have not been fully established yet. In this paper, a new evaluation method of degree of identification between two transfer functions is proposed. In the proposed method, a frequency window is employed and cross‐correlation factor is calculated with moving the window. Furthermore, the proposed method is applied to transfer functions of real transformers with or without some abnormalities. Based on this discussion, objective criteria for diagnosis of abnormalities of transformer windings by FRA are proposed. The proposed criteria are based on a few data of transformers with some abnormalities. Therefore, the proposed criteria are tentative and they would be improved by accumulation of further data.     

Plasma Behavior in a High‐Temperature Noble Gas Plasma Disk‐Shaped MHD Power Generator

R‐θ two‐dimensional numerical simulations have been carried out to clarify the plasma behavior in a high‐temperature noble gas plasma disk‐shaped magnetohydrodynamic (MHD) generator. At low inlet total temperature and high load resistance, the plasma has spiral structure which is similar to the nonuniform structure under the weak noble gas ionization condition in a seed‐plasma MHD generator. As seen in a linear‐shaped Faraday‐type MHD generator, the plasma becomes stable with increase in the inlet total temperature because the coulomb collision of electrons becomes dominant. Even at low inlet total temperature, the ionization instability can be suppressed for low load resistance, because the relatively low electron temperature due to less Joule heating makes the ionization relaxation time longer than plasma residential time.     

MQL深孔钻削中关键因素的最适化研究

采用了微量润滑技术的钻削在长距或小孔径的条件下有必要对所供给的油雾和压缩空气进行最佳化分析.本文首先对切削变形与切削热分布的总能量进行了分析,并在把普通钻削过程中油雾假设为稳态可压缩绝热紊流状态的假设条件下,通过分析得到油膜厚度、气流速度、压缩空气温度和刀具平均温度等重要影响参数的相互关系.最后,给出微量润滑钻削条件下,切削过程中所需的油膜和压缩空气的最佳容量.     

等温淬火温度对奥贝球铁水脆化行为的影响

研究了等温淬火温度对奥贝球铁(ADI)水脆化行为的影响，水附着条件下不同等温淬火温度处理的ADI均发生水脆化行为，抗拉强度和伸长率显著降低；但随着等温淬火温度升高，ADI的水脆化程度降低。高强度的ADI、淬火回火球铁和珠光体球铁均发生水脆化行为，而铁素体含量高的铸态球铁和铁素体球铁无明显的水脆化行为。