Comparative economic and environmental benefits of ownership of both new and used light duty hydrogen fuel cell vehicles in Japan

We present a novel study of the differential total costs of ownership and marginal cost of life cycle emissions abatement for owners of both new and used light duty fuel cell and internal combustion engine vehicles in Japan. We find the emergence of used FCVs in the fleet significantly improves the economic and emissions savings over ICEVs. The cumulative life cycle GHG emissions reductions rapidly increase when FCVs exceed 55%–70% of total LDVs. Life cycle emissions in the vehicle fleet increase 40% if hydrogen is produced from SMR with CCS rather than from solar or wind based electrolysis. Fuel cell cost and electrolyser efficiency are key factors in achieving benefits. Finally, if the early time growth of FCVs to 2030 can be maintained near 50% the government 2050 emissions reduction target of 80% reduction from a 2013 base can be achieved.     

盛开的“阴影”——具有感知的百叶窗

正在夏季,树木会伸展枝叶,以便更好地遮挡强烈的阳光;而在冬季,当光线较弱时,树叶大都会枯萎凋零。nendo最近采用仿生理念设计了一款产品,打破了人们对窗帘遮挡窗口的普遍认知。在我们的生活中,人们会通过多种方式来控制透过窗户的光线,从而使室内的光线、温度更为舒适,同时保护自己的隐私,譬如下垂的窗帘,卷起的幕帘,可转换角度的百叶窗……     

Fabrication of Porous Copper with Directional Pores by Continuous Casting Technique Through Thermal Decomposition of Hydride

Lotus-type porous copper with aligned long cylindrical pores was fabricated by continuous casting technique through thermal decomposition method (TDM) in an argon atmosphere of 0.1 MPa. A pellet of titanium hydride was supplied into molten copper with adjusting the time interval to maintain the constant concentration of hydrogen to be dissolved in the melt, when the transfer velocity of the unidirectional solidification is changed. Long lotus-type porous copper slabs were fabricated with constant solidification velocity. The effect of the transfer velocity on the porosity and pore size was investigated. The average pore diameter was independent of the transfer velocity, but the porosity is slightly dependent on the velocity. It is apparent that the continuous casting technique can be applicable for production of lotus metals through TDM.     

Picosecond carrier dynamics induced by coupling of wavefunctions in a Si-nanodisk array fabricated by neutral beam etching using bio-nano-templates

The picosecond carrier dynamics in a closely packed Si-nanodisk (Si-ND) array with ultrathin potential barrier fabricated by neutral beam etching using bio-nano-templates was investigated by time-resolved photoluminescence (PL). The PL decay curves were analyzed as a function of photon energy by the global fitting method. We show three spectral components with different decay times, where the systematic energy differences of the spectral peaks are clarified: 2.03 eV for the fastest decaying component with a decay time τ = 40 ps, 2.02 eV for τ = 300 ps, and 2.00 eV for τ = 1.6 ns. These energy separations ranging from 10 to 30 meV among the emissive states can be attributed to the coupling of wavefunctions of carriers between neighboring NDs.     

Hardness effect of stainless steel substrates on tribological properties of water-lubricated DLC films against AISI 440C ball

Diamond-like carbon (DLC) films were deposited on stainless steel substrates with different hardness by thermal electron excited plasma CVD method, and their tribological properties in water-lubricated conditions were investigated. EDS was used to estimate the wear of the films. The results show that the hardness of the substrates has little effect on the friction and, the wear loss of the films is much smaller than that measured by an optical interferometer. The deep wear track is mainly due to the plastic deformation of the substrates and the films but not due to wear. However, the failure of the films is closely related to the hardness of their substrates. The harder the substrate, the higher the failure-resistant capability. The film deposited on a soft substrate is easy to crack and fail due to the low deformation resistance of the substrate and rubbing at a high contact-pressure. On the other hand, the wear of the counter balls increases with the hardness of the substrates.     

PWM逆变器下永磁同步电动机中永磁体的三维涡流分析

对于永磁同步电动机中永磁体的发热及温升,快速准确地分析永磁体的涡流损耗是其关键问题所在.用场路紧密耦合方法,建立了考虑永磁体分割的三维有限元模型,对一台在脉宽调制(PWM)逆变器驱动下的30 kW/50 Hz表贴式永磁同步电动机进行仿真研究,分析了其气隙旋转磁场、电枢电流,以及在不同载波频率下永磁体的涡流损耗.研究表明:在载波谐波作用下,永磁体的涡流损耗比在正弦电压驱动下大幅增加,并将引起更大的温升.输入电流波形、转矩和功率平衡关系等试验结果表明,该分析方法能准确计算出永磁体的涡流损耗,为下一步的温升研究奠定了基础.     

Surge voltages and currents into a customer due to nearby lightning

This paper presents experimental results of lightning surges incoming into a customer due to lightning to an antenna of the customer, a pole and a ground nearby the customer, and briefly discusses lightning current distribution in the customer, a distribution line and a telephone line. Based on experimental results, modeling of each component is explained, and EMTP simulations are carried out. The ground voltage rise is represented by a mutual resistance between grounding electrodes. EMTP simulation results have been observed to agree qualitatively with the measured results, and it becomes possible to investigate lightning surges and current distribution in a customer by an EMTP simulation.     

Effect of air space in waterproof sealed case containing transmitter and receiver of wireless power transfer in sea water

In this study, the effect of air space in waterproof sealed case of undersea magnetic field resonance type wireless power transfer (WPT) is reported. It has been reported that the transmission power is increased by the air space between the transmitter and receiver coil in the waterproofing case and the wall surface of the case. We evaluated the dependence of the thickness of the air space from measurement and magnetic field analysis. The measurement and magnetic field analysis results indicated the similar tendency to increase the transmission power by 9.8% with the 10‐mm air space at the transmitter side and the 30‐mm air space at the receiver side.     

A study of AC link and DC link method for wind power generation connected to electric power system

In this paper, grid‐connection of wind power generators was evaluated from the viewpoint of frequency fluctuation. Wind power generation is a power generation method that depends on natural energy, and there is some concern that it may exert a negative influence on electric power quality. As a result, it is necessary to maintain high electric power quality when wind power generation is connected to the grid. The AC link method, the AC‐DC link method, and the DC link method are alternatives for grid connection of wind power generators. The model system was constructed with the use of a synchronous generator and an induction generator as wind power generator, and verification experiments were performed. Verification experiments using the various grid‐connection methods for each generator were conducted. The steadiest frequency characteristic was obtained in the DC link method. In particular, the stability level was highest in the wind power generation system using the DC link method with a wound‐rotor induction generator. Generally, induction generators are grid‐connected by the AC link method. Therefore, grid‐connection of induction generators by the DC link method appears effective from the viewpoint of frequency fluctuation. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(3): 21–30, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21196