Heavy metals removal from automobile shredder residues (ASR)

The fate of heavy metals during a separation process for automobile shredder residues (ASR) was investigated. A washing method to remove heavy metals from the ASR was also investigated. Although the separation process was not designed for removal of heavy metals, but for the recovery of reusable materials, the heavy metal content in the ASR was efficiently decreased. The concentrations of Pb, Cr and Cd in ASR were effectively reduced by a nonferrous metals removal process, and the As concentration was reduced by the removal of light dusts during the separation process. Five heavy metals (As, Se, Pb, Cr, Cd) remaining in the ASR after the separation process satisfied the content criteria of the Environmental Quality Standards for Soil (EQSS), while the concentrations of As, Se, Pb in the leachate from the remaining ASR did not satisfy the elution criteria of the EQSS. After additional washing of the remaining ASR with a pH 1 acid buffer solution, the As, Se, and Pb concentrations satisfied the EQSS for elution. These results indicate that an ASR residue can be safely recycled after a separation process, followed by washing at acidic pH.     

Advanced energy-efficient house (HARBEMAN house) with solar thermal, photovoltaic, and sky radiation energies (experimental results)

An energy-independent residential house (‘HARBEMAN house’; Harmony BEtween Man And Nature), incorporating sky radiation cooling, solar thermal, and photovoltaic energies was built in Sendai, Japan during July, 1996. This paper reports monitored results of this house since September 1996 to date. The paper also presents simulation results for the HARBEMAN house and its results compared with the annual experimental data. The HARBEMAN house, which meets almost all the energy demands, including space heating and cooling, domestic hot water, electricity generated by photovoltaic cell and rainwater for standard Japanese homes. Sky radiation cooling, solar thermal/photovoltaic (PV), and underground coolness as well as rainwater and waste heat are utilized in combination. Annual variations of water temperature in the underground main tank, heating/cooling/domestic hot water demands, collected and emitted heats by the solar collector and sky radiator have been monitored.     

Fluid flow and heat transfer of natural convection at a slightly inclined,upward‐facing,heated plate

Natural convective flows over upward‐facing, inclined plates were investigated experimentally, with an emphasis on the role of opposing flows that appear over the plates inclined slightly from the horizontal line. The flow fields over the plates and the surface temperatures of the heated plates were visualized with both dye and a liquid‐crystal thermometry. The results showed that both the descending and ascending flows appeared over the plates when the inclination angles of the plates were less than 15°. The two flows collided with each other at a certain distance from the plate edge, and then detached from the plate to become a thermal plume. It was found that the above distance was determined solely by the inclination angles and was independent of sizes and heat fluxes of the plates. The local heat transfer coefficients of the plates were also measured. The results showed that the heat transfer from the plate was enhanced by the occurrence of the descending flows. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(5): 362–375, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10036     

Refractive index patterning of tellurite glass surfaces by ultra short pulse laser spot heating

Dot patterns of refractive indices were formed by the laser pulse irradiation on the tellurite glasses. The ternary tellurite glasses of TeO₂-Na₂O-Al₂O₃, TeO₂-Na₂O-GeO₂ and TeO₂-Na₂O-TiO₂ doped with 2 mol% of CoO were irradiated by a femtosecond pulse laser beam (800 nm) or by a green light beam (532 nm) from a second harmonic generator of a Q switch pulse YAG laser. The refractive index map of the glass was composed with an He-Ne laser beam by an scanning ellipsometric technique at a resolution of 100 m × 50 m, indicating that the spots possessing refractive index lower by about 0.05–0.38 than the surroundings were formed at the region irradiated by the laser beam. The irradiation of the femtosecond laser beam generated the dot patterns roughly equivalent to the beam size. The change of refractive index could be tunable by adjusting laser power, suggesting that the process could be applied to optical recording.     

On Fuzzy-Mathematical Programming

In problems of system analysis, it is customary to treat imprecision by the use of probability theory. It is becoming increasingly clear, however, that in the case of many real world problems involving large scale systems such as economic systems, social systems, mass service systems, etc., the major source of imprecision should more properly be labeled ‘fuzziness’ rather than ‘randomness.’ By fuzziness, we mean the type of imprecision which is associated with the lack of sharp transition from membership to nonmembership, as in tall men, small numbers, likely events, etc. In this paper our main concern is with the application of the theory of fuzzy sets to decision problems involving fuzzy goals and strategies, etc., as defined by R. E. Bellman and L. A. Zadeh [1]. However, in our approach, the emphasis is on mathematical programming and the use of the concept of a level set to extend some of the classical results to problems involving fuzzy constraints and objective functions.     

Study of a coal-fired transonic disk MHD generator for a power system with CO2 recovery

A conceptual design of a transonic disk MHD channel is carried out for a power generation system with liquefaction recovery of CO₂. A previous study has shown that the subsonic disk MHD channel has rather poor performance and the supersonic disk channel yields sufficiently high power output, although its stability should be improved. The present paper proposes a transonic disk channel which can be stably operated with high power output. It is assumed that the transition between supersonic flow and subsonic flow is accompanied by a cylindrical shock wave in the channel. The transonic channel yields enthalpy extraction ratios of 20.2 and 22.9%, respectively, for thermal inputs of 1100 and 2000 MW, and is nearly equal to the performance of the supersonic channel. The stability of the transonic disk channel is examined by r-0 two-dimensional time-dependent calculations. The two-dimensional analysis shows that the transonic disk channel works stably with fewer load sections than the supersonic channel even when inlet perturbations are added. © 1998 Scripta Technica. Electr Eng Jpn, 122(2): 21–29, 1998     

Downscaling mesoscale meteorological models for computational wind engineering applications

Considerable interest exists in joining the capabilities of mesoscale meteorological models (MMM) with those of computational wind engineering (CWE) models to produce realistic simulations, which address emerging issues in wind engineering and environmental applications. The model equations are similar for MMM and CWE, but there are significant differences in the objectives and approaches. Complete synthesis of these models is still premature and computational burdens are enormous. Appropriate procedures for joining these models have not been established yet and measurement data required for verification is limited.For convenience in presentations and discussions, coupling methods are divided into four groups: (1) coupling MMM and CWE models for up-scaling or downscaling, (2) up-scaling a CWE model to include the mesoscale meteorological influences, (3) downscaling an MMM to include the CWE capabilities, and (4) a combination of the above three approaches. Mochida et al. (this issue) focuses on up-scaling CWE from an engineering point of view and the present paper focuses on downscaling MMM from a meteorological point of view.Topics addressed here are (1) to understand the differences in the purposes and approaches of MMM and CWE models and (2) to identify issues and explore ways of coupling MMM and CWE modeling capabilities.     

Modification of Takaishi-Sensui formula for a diaphragm gauge system connected by an arbitrary length pipe

The thermal transpiration effect in a vacuum system, where a circular pipe connects a capacitance diaphragm gauge (CDG) and a vacuum vessel, was numerically investigated using the direct simulation Monte Carlo (DSMC) method. The simulated pressure ratios were plotted versus the Knudsen number K, over the range 10⁻³ ≤ K ≤ 10³, for a fixed diameter and various pipe lengths. The curve obtained here was compared with that obtained using the Takaishi-Sensui formula (T-S curve). For a long pipe, with λ ≥ 10, (λ: aspect ratio of length to diameter), the simulated curve agreed well with the T-S curve over the entire examined range of K. For a shorter pipe (λ < 10), the simulated curve seemed to shift in the low K (high pressure) direction, with respect to the T-S curve, and the distance between the curves abruptly increased with decreasing λ. The discrepancy for a short pipe was found to be removable by rescaling the Knudsen number. The discrepancy that originally existed for a long pipe could also be reduced, if the reflection on the pipe wall obeyed an incompletely accommodated Maxwell model.     

Chemical and biological degradation of 5-fluorouracil prodrugs having high serum albumin binding potencies

In order to understand the fundamental structural features which yield both high serum albumin binding potency and desired property as a prodrug, the derivatization was performed at N-1 or N-3 position in 5-fluorouracil. The N-3 derivatives were more stable than N-1 derivatives in vitro, whereas they were metabolized quickly in vivo. It is suggested that N-1 position should be blocked to avoid fast metabolism in vivo.     

Performance and conceptual design of superconducting magnet for disk MHD generator

This paper describes superconducting magnets coupled with two kinds of disk-type MHD generators. One is coupled with a disk generator in the closed-cycle MHD experimental facility FUJI-1. The other is for a full-scale disk MHD generator. These are split-pair magnets. In the magnet for the FUJI-1 facility, a unique structure which supports the coils against the electromagnetic force has been fabricated and the magnet has been operating stably. During MHD power generation experiments, an induced voltage across the terminals of the coil was measured. A magnitude of the Faraday current in the generator was calculated from this induced voltage. A possible construction of magnetics for a full-scale disk MHD generator is indicated. It is suggested that a high performance of the generator (output power density of 0.3-1 GW/m³) can be obtained with high magnetic field up to 10 T.