地铁站内烟气流动特性和消防安全

介绍了地铁站内烟气流动和控制的试验和数值研究。在三个真正地铁站内利用甲醇油池火作为燃料进行了试验，用所获得数据来验证地铁站火灾数值模型，并进一步检验其烟控系统的性能。在站内使用了制量烟气流动模型，再现了最简单条件下每个站点的试验结果，然后把结果跟其他试验条件下的试验结果进行了比较。最后，用模型预测更复杂火灾的烟气流动情况。另外，还讨论了地铁系统的有效设计和火灾安全设施的正常运作情况。通过限制内饰面材料的燃烧性能或者安装自动喷淋系统都可以有效控制热释放速率，且在站点两端开设逃生路线、站台和地铁隧道直接卷帘的正常启动等可有效保证安全疏散。     

A SPECIFIC QUALITATIVE DETECTION METHOD FOR PEANUT (ARACHIS HYPOGAEA) IN FOODS USING POLYMERASE CHAIN REACTION

A qualitative method for detection of peanuts in foods using polymerase chain reaction was developed. A universal primer pair CP 03‐5′/CP 03‐3′ was designed to confirm the validity of the DNAs for PCR. The plant‐specific amplified fragments were detected from 13 kinds of plants using the universal primer pair. In addition, for the specific detection of peanuts with high sensitivity, the primer pair agg 04‐5′/agg 05‐3′ was designed to detect the gene encoding the peanut agglutinin precursor. The primer pair specifically generates a 95‐bp amplified fragment from peanut genomic DNA. Five hundred femto grams of peanut genomic DNA can be detected using the established method. The same qualitative results were obtained from both model processed and nonprocessed food samples containing 0.001, 0.01 and 0.1% of peanut. Moreover, it was shown that the trace amount of peanut in the commercial food products could be qualitatively detected using this method. The reproducibility and applicability of the proposed methods were verified in a six‐laboratory collaborative study.     

An Electricity Price Forecasting Model with Fuzzy Clustering Preconditioned ANN

In this paper, a hybrid model of fuzzy clustering and ANN (Artificial Neural Network) is proposed for electricity price forecasting. Due to the complicated behavior of electricity price in power markets, market players are interested in maximizing profits while minimizing risks. As a result, more accurate models are required to deal with electricity price forecasting. This paper proposes a new method that makes use of fuzzy clustering preconditioned GRBFN (Generalized Radial Basis Function Network) to provide more accurate predicted prices. Fuzzy clustering plays a key role to prevent the number of learning data from decreasing at each cluster. GRBFN is one of efficient ANNs to approximate nonlinear systems. Furthermore, a modified GRBFN model is developed to improve the performance of GRBFN with the use of DA (Deterministic Annealing) clustering for the parameters initialization and EPSO (Evolutionary Particle Swarm Optimization) for optimizing the parameters of GRBFN. The proposed method is successfully applied to real data of ISO New England, USA.     

Gas-sensor properties of SnO2 films implanted with gold and iron ions

SnO₂ gas-sensor films were modified by implantation of gold and iron ions. The change in electrical resistivity of the films caused by inflammable gases, H₂, CO, CH₄ and C₂H₅OH, was measured in the temperature range 100–500°C, and compared to non-implanted films. The morphological changes caused by gold and iron ion implantation were also investigated by atomic force microscopy. After ion implantation and annealing at 600°C, the sensitivity to H₂ and CO gas was found to increase, and the dynamic range of the sensitivity to ethanol was improved. The sensitivity to CH₄ was low before and after ion implantation. Fe₂O₃ (3%SnO₂) film was also modified by gold ion implantation for comparison. This revised version was published online in July 2006 with corrections to the Cover Date.     

Contribution of Paramyosin to Marine Meat Gel Characteristics

The properties of the paramyosin-natural actomyosin system gels were considerably improved by paramyosin, and a strong and firm gel was formed. This effect of paramyosin on gel properties was large at relatively low paramyosin contents. Paramyosin considerably altered the characteristic texture of the marine meat gel products made from invertebrate meats. Two-step heating, including the low temperature setting, was effective in increasing the gel strength for the paramyosinnatural actomyosin system gels. The strengthening effect of setting on the gel strength became larger on increasing the paramyosin content.     

Analytical Method Applying a Mathematical Model for Axial‐Gap‐Switched Reluctance Motor

In this paper, an analytical method using a mathematical model for switched reluctance motors (SR motors) is proposed. The feature of this method is the representation of the effect of the mutual flux on the integral model by applying transient analysis utilizing preprocessed inductance tables. The advantage of this method is that the analysis time is reduced in comparison with the finite element method (FEM). The calculation results for the torque show little difference between the FEM and the proposed method, and the computation time was shortened. A 3.7‐kW prototype axial‐gap SR motor designed using the proposed method delivered the specified performance.     

A Verification of Estimation Accuracy of Lightning Current Waveform and Charge Transfer from Measured E‐Field Waveform

To establish effective countermeasures on power facilities against lightning damage, it is necessary to clarify the lightning characteristics such as current parameters at the area of interest. In order to collect lightning current parameters effectively, the authors have observed electric and magnetic field waveforms simultaneously at south Kyushu, where the lightning flash density in summer is high. Based on observed electric field waveforms, the lightning current parameters have been estimated by adopting the Diendorfer–Uman model (DU model) as the return‐stroke model. In this paper, the accuracy of the estimated return‐stroke current waveform is verified by comparison with directly measured return‐stroke current waveform, along with the accuracy of the estimated charge transfer from the electric field waveform measured with a slow antenna.     

Development of Electrolytic Capacitor Less Photovoltaic Grid Connected Inverter with Boost‐Up Type Active Buffer Circuit

This paper proposes a configuration of a single‐phase voltage source inverter that features power decoupling capability. Generally, the converter connected to a single‐phase grid employs bulky dc link capacitors such as electrolytic capacitors in order to decouple the power ripple with twice the frequency of the power supply. The power ripple in the proposed circuit is compensated by an active buffer with small capacitors. In this paper, the fundamental operations of the proposed converter are confirmed by experimental results. From the experimental results, the output current total harmonic distortion (THD) is 3.51%, the ratio of the input current is 14.3%, and the output power factor is over 99%. In addition, the volume of the proposed circuit is reduced by 61% when the carrier frequency is 64 kHz compared to that with a carrier frequency of 16 kHz. Finally, from an evaluation of the power density using Pareto front curves, the proposed circuit achieves high power density in comparison with the conventional circuit.     

Ultra-High-Speed Performance of Ball Bearings and Annular Seals in Liquid Hydrogen at Up to 3 Million DN (120,000 rpm)©

The ultra-high-speed performance of a hybrid ceramic 25-mm-bore ball bearing, as well as that of floating-ring seals with a sealing diameter of 30 mm, was determined in liquid hydrogen at speeds to 120,000 rpm, 3 million DN, under thrust loads to 3,140 N and sealed pressures to 1.7 MPaG. The bearings had Si₃N₄ balls and a single outer land-guided retainer. The hybrid ceramic bearing exhibited excellent performance at high load, contrasting with the seized all-steel bearing; however, the ceramic balls developed superficial micro-cracks due to frictional heating. Effective cooling of the bearing was achieved by increasing the jet speed through the nozzles. The bearing power loss drastically increased with increasing speed and cooling flow rate. The critical load capacity without bearing damage was also evaluated. Furthermore, the sealing performance of the one-ring seal was superior to that of the two-ring seal in preventing the sealing ring seizure against the runner.     

Effect of software maintenance policies for a hardware-software system

It is generally considered that a fault-tolerant system is composed of a hardware system and a software system. The present work assumes that a hardware system is composed of two units (processors). Two software maintenance policies depending on the priority maintenance for software are proposed. In particular, software maintenance policies are discussed by evaluating the (time dependent) transient solutions of the reliability measures. Formulating Markov process models for two policies, and calculating the reliability measures numerically, two software maintenance policies for the resulting reliability measures are compared.