Can land use regulations and taxes help mitigate vehicular CO2 emissions? An empirical study of Japanese cities

This study advocates a multi-dimensional urban planning strategy to help combat climate change under local—and not national—policies. However, the literature does not provide adequate guidance to local governments seeking to enhance urbanization and in turn reduce vehicular carbon dioxide (CO₂) emissions. Therefore, this study sheds light on the effects of the following four urban planning instruments on vehicular CO₂ emissions: urbanization promoting areas, urbanization control areas, urban planning taxes and property taxes. Using Japanese city-level data from 1990 to 2010, we find that the two urbanization area planning instruments and the urban planning taxes help lower emissions by increasing population density in low-density cities and that property taxes help reduce emissions in high-density cities. However, the increased population density associated with these instruments can lead to other negative outcomes, including increased traffic accidents, increased crime and a decrease in the facility condition index. City governments should consider complementary policies to mitigate such negative outcomes when employing planning instruments aiming to increase population density.     

Fundamental Behavior of Direct-Coupled Submicrosecond Pulse Energization in Electrostatic Precipitators

The fundamental characteristics of the direct-coupled pulse energization in electrostatic precipitators (EP's) are investigated in a test rig comprised of a coal pulverizing facility, a furnace, a gas cooling system, and an EP. The EP consisted of a corona electrode with barbed wires and a collection electrode with 300-mm duct spacing. This simulates the type of EP normally used in a coal-fired power station. The pulse-energized collection field shows a very high collection performance of more than 99 percent collection efficiency and the performance enhancement compared to the conventional dc energization, causing very severe back corona, becomes as large as H = 2.50.H is the enhancement factor in terms of the Deutsch migration velocity in the case of the very high resistivity dust of rd = 2 x 1013 ?cm at the gas temperature of Tg = 150°C. Even at the lower level of the dust resistivity at Tg = 110°C, where no back corona occurs in the dc-energized collection field, the performance enhancement is as large as H = 1.21. The mechanism of such great performance enhancement is likely to be the result of the very uniform and very intense formation of corona plasmas on the wires as a result of the very fast rise in the pulse voltage applied and a special sawtooth waveform of the operating voltage between the corona and collection electrodes.     

Spatial indexing of high-dimensional data based on relative approximation

We propose a novel index structure, the A-tree (approximation tree), for similarity searches in high-dimensional data. The basic idea of the A-tree is the introduction of virtual bounding rectangles (VBRs) which contain and approximate MBRs or data objects. VBRs can be represented quite compactly and thus affect the tree configuration both quantitatively and qualitatively. First, since tree nodes can contain a large number of VBR entries, fanout becomes large, which increases search speed. More importantly, we have a free hand in arranging MBRs and VBRs in the tree nodes. Each A-tree node contains an MBR and its children VBRs. Therefore, by fetching an A-tree node, we can obtain information on the exact position of a parent MBR and the approximate position of its children. We have performed experiments using both synthetic and real data sets. For the real data sets, the A-tree outperforms the SR-tree and the VA-file in all dimensionalities up to 64 dimensions, which is the highest dimension in our experiments. Additionally, we propose a cost model for the A-tree. We verify the validity of the cost model for synthetic and real data sets. Edited by T. Sellis. Received: December 8, 2000 / Accepted: March 20, 2002 Published online: September 25, 2002     

Ultrashort X-ray pulse generation using subpicosecond electron linac

As a promising tool for ultrafast material analyses, we propose to utilize the X-ray pulse which may be generated in a quite simple manner using subpicosecond electron linacs. The properties of the X-ray were numerically studied with the EGS4 code. Verification of the X-ray generation was also conducted at the Nuclear Engineering Research Laboratory (NERL) linac and clear diffraction patterns of characteristic X-ray were obtained for typical single crystals.     

Analysis of electromagnetic force in wire-EDM

This paper clarifies the mechanism of how electromagnetic force applied to the wire electrode in wire electrical discharge machining (wire-EDM) is generated. This electromagnetic force is caused not only by DC component but also by AC components of the discharge current supplied to the wire. We therefore developed and used a two-dimensional finite element method (FEM) program to analyze the electromagnetic field taking into account electromagnetic induction. Assuming that trapezoidal pulse current is supplied to the wire, distributions of the current density and magnetic flux density were analyzed and changes in the electromagnetic force applied to the wire were calculated. Wire movement when the electromagnetic force alone was applied to the wire was also calculated. The calculated wire movement agreed with the measured wire movement when pulse current actually used in WEDM was supplied to the wire, clarifying the mechanism of electromagnetic force generation.     

Team performance modeling for HRA in dynamic situations

This paper proposes a team behavior network model that can simulate and analyze response of an operator team to an incident in a dynamic and context-sensitive situation. The model is composed of four sub-models, which describe the context of team performance. They are task model, event model, team model and human–machine interface model. Each operator demonstrates aspects of his/her specific cognitive behavior and interacts with other operators and the environment in order to deal with an incident. Individual human factors, which determine the basis of communication and interaction between individuals, and cognitive process of an operator, such as information acquisition, state-recognition, decision-making and action execution during development of an event scenario are modeled. A case of feed and bleed operation in pressurized water reactor under an emergency situation was studied and the result was compared with an experiment to check the validity of the proposed model.     

Low-noise multiwavelength transmitter using spectrum-slicedsupercontinuum generated from a normal group-velocity dispersion fiber

Aiming at the application of supercontinuum (SC) generated from a fiber with a normal group-velocity dispersion (GVD) to multiwavelength transmitters, we theoretically study the enhancement of optical-amplifier noise in the SC-generation and spectrum-slicing processes. We find that significant enhancement of noise is not observed in these processes. The bit error rate measurement actually shows that the power penalty induced by these processes is less than 1 dB in all spectrum-sliced channels. These results assure low noise of the multiwavelength transmitter using spectrum-sliced SC generated in a normal GVD fiber     

TiO2 thin films using organic liquid materials prepared by Hot-Wire CVD method

TiO₂ thin films prepared by Hot-Wire CVD method have been studied as a protecting material of transparent conducting oxide (TCO) against atomic hydrogen exposures for the fabrications of Si thin film solar cells. It was found that electrical conductivity of the films at room temperature reached a value of 0.4 S/cm. This value is 2-3 orders of magnitude higher than that of TiO₂ films prepared by RF magnetron sputtering and electron-beam evaporation methods in our previous works. The conductivity improvement seems to be partly due to the enlargement of TiO₂ crystallites.     

Influence of cathode polarization on the chromium deposition near the cathode/electrolyte interface of SOFC

Chromium poisoning phenomena were compared among three SOFC cathodes using (La_0.8Sr_0.2)_0.98MnO₃ (LSM), La_0.6Sr_0.4Fe_0.8Co_0.2O₃ (LSCF) and LaNi_0.6Fe_0.4O₃ (LNF) at 700 °C by changing cathode polarization (0–400 mV). Chromium vapor deposited near the electrolyte for LSM and LNF, and the amount of the deposition increased with increasing cathode polarization. In the case of LSCF, chromium deposited near the cathode surface under smaller cathode polarization (≤200 mV). Under larger cathode polarization (≥300 mV), however, chromium deposition near the cathode/electrolyte interface similarly increased for the three cathodes. Cathode polarization facilitated the chromium deposition and there seemed to be no correlation with the current density. Microscopic distribution of the deposited chromium, which was located on the surface of LSM, LSCF, LNF grains, and also on the surface of zirconia and ceria, seemed to correspond to the distribution of oxygen vacancy by cathode polarization at the electrode reaction sites. Chromium deposition on the zirconia surface seemed to be assisted by metal oxides segregated from the cathode material, which can conduct electron required for generating oxygen vacancy continuously. Oxygen deficiency on the surface of the deposited chromium was confirmed and interdiffusion of chromium and zirconium caused by cathode polarization was also suggested.     

Temporal-Talbot-effect-based preprocessing for pattern-effect reduction in all-optical clock recovery using a semiconductor-optical-amplifier-based fiber ring laser

We propose and experimentally demonstrate the temporal-Talbot-effect (TTE)-based preprocessing for the pattern-effect reduction in the all-optical clock recovery using a semiconductor-optical-amplifier (SOA)-based fiber ring laser (SOA-FRL). The TTE-based preprocessing successfully reduced the pattern effects of the recovered clock pulses, so that the 10-GHz clear optical clock pulses were recovered from a 10-Gbit/s return-to-zero on–off keying (RZ-OOK) pseudo-random bit sequence (PRBS) optical signal. “Peak variation” and “Pattern-dependent intensity noise (PDIN)” were proposed and were utilized as parameters to quantitatively evaluate the pattern effects, from which recovered clock pulses suffer, in the temporal domain and the frequency domain, respectively. Peak variation was reduced from 77.2% to 36.2%, and PDIN was improved from ?103 dBc/Hz to ?110 dBc/Hz with the aid of the TTE-based preprocessing. Furthermore, we examined the tolerance of the proposed technique by intentionally deviating the input signal’s bit-rate by ±190 Mbit/s (±2% of the bit-rate) from the optimum condition for the TTE. As compared with the PDIN value for the pulse train obtained by the direct injection of the non-processed signal into the SOA-FRL, the PDIN of the recovered clock pulses using the preprocessed signal indicated improvements over the entire measurement range of ±190 Mbit/s, which corresponds to the wavelength-dispersion deviation of ±56 ps/nm (±4% of the wavelength-dispersion applied to the input signal) from the optimum value.