Re-evaluation and re-construction of water purification system using soil. II. Removal of pollutants from infiltrating water.

Presented in this paper are the results of a series of column experiments and a pilot scale test conducted to develop the treatment system of freshwater and wastewater by their percolation through soil and the other materials at the rate of a few metres per day. Materials that had high ability to sorb fulvic acid (FA hereafter) and phosphate ion were selected based on the results of the batch sorption tests and were processed into beads before subjecting them to the column test. The results of the column experiment suggested that the reagents added to increase the strength of the beads reduced the sorption of FA, thus causing the early breakthrough of the FA injected into the column. Less effect from the bead processing was observed for the removal of phosphate ion. Pilot scale test showed that the removal of particulate fraction of phosphorus differed among the materials used. The bead processing technique that can ensure the high water permeability while maintaining the sorption capacity of the material was required for further development of the treatment system.     

A fuzzy self-tuning parallel genetic algorithm for optimization

The genetic algorithm (GA) is now a very popular tool for solving optimization problems. Each operator has its special approach route to a solution. For example, a GA using crossover as its major operator arrives at solutions depending on its initial conditions. In other words, a GA with multiple operators should be more robust in global search. However, a multiple operator GA needs a large population size thus taking a huge time for evaluation. We therefore apply fuzzy reasoning to give effective operators more opportunity to search while keeping the overall population size constant. We propose a fuzzy self-tuning parallel genetic algorithm (FPGA) for optimization problems. In our test case FPGA there are four operators—crossover, mutation, sub-exchange, and sub-copy. These operators are modified using the eugenic concept under the assumption that the individuals with higher fitness values have a higher probability of breeding new better individuals. All operators are executed in each generation through parallel processing, but the populations of these operators are decided by fuzzy reasoning. The fuzzy reasoning senses the contributions of these operators, and then decides their population sizes. The contribution of each operator is defined as an accumulative increment of fitness value due to each operator's success in searching. We make the assumption that the operators that give higher contribution are more suitable for the typical optimization problem. The fuzzy reasoning is built under this concept and adjusts the population sizes in each generation. As a test case, a FPGA is applied to the optimization of the fuzzy rule set for a model reference adaptive control system. The simulation results show that the FPGA is better at finding optimal solutions than a traditional GA.     

Sub-boundaries in3He and4He single crystal and their migration below 1K observed by X-ray topography

The observation of alterations in crystal structure at ultra-low temperatures by X-ray diffraction, made possible by the realization of synchrotron radiation use after a quarter of this century, plays an important role in obtaining an understanding of the base structure of solids. For that, two types of³He-⁴He dilution refrigerators with a modified version of the top-loading facilities were installed at the BL-3C₂ and 6C₁ stations of the Photon Factory. In BL-3C₂, the behaviors of lattice defects in solid helium have been studied by X-ray topography. In this note, the migrations of sub-boundaries in³He and⁴He single-crystals are reported as being the result of an annealing effect. After annealing hcp⁴He single crystals for 80min at 0.5K, no change in crystallographic orientations could be easily observed from white SR X-ray topographs. In the same type topographs of bcc³He single crystals after annealing for several hours at 03K, migration of sub-boundaries were conspicuously discerned.     

3Beta-hydroxysteroid dehydrogenase activity in human osteoblast-like cells

In spite of improvements in single or double lung transplantation (LT) technique, complications after LT are not uncommon; the most frequent ale anastomotic complications, infections and rejection (acute or chronic). Early detection of complications of LT allows the optimal therapeutic option to be taken, yielding decreased morbidity and mortality. In some cases, CT plays a key role in early detection of several complications of LT that may not be depicted with other diagnostic modalities, so that knowledge of their CT features is important. In this pictorial review, the authors describe the spectrum of CT features of the complications of LT (including reimplantation response, mechanical problems, acute and chronic rejection, infection, lymphoproliferative disorders, recurrence of the initial disease and complications involving the pleura and the anastomotic sites). In addition, the authors analyze the value of CT compared to that of the other available modalities for the detection of complications of LT.     

Evaluations of tribological characteristics of PFPE lubricants on DLC surfaces of magnetic disks

This article presents measurements of adhesion and friction of perfluoropolyether (PFPE) lubricant films dip-coated on magnetic disks covered with diamond-like carbon (DLC) film. We have developed a custom-built pin-on-disk type micro-tribotester to perform the tribological measurements. The adhesion tests were performed by pulling down/up a 1.5-mm-diameter glass ball on a stationary disk surface, and the friction tests were carried out by sliding the glass ball on a rotating disk surface without changing head-disk interface conditions from the adhesion tests. Experiments were performed for the different kinds of 2- and 6-nm-thick PFPE lubricants (polar: Zdol4000 and Zdol2000; nonpolar: Z03) under lightly loaded and slow sliding conditions to minimize disturbance against the molecular layered structure. The adhesive forces were found to decrease with increasing film thickness in the order of Z03 > Zdol2000 > Zdol4000 (decreasing rate), which closely corresponds to the order of monolayer thickness, and then to saturate to almost the same calculated values. As for the friction forces of 2-nm-thick films, Zdol2000 featured extraordinarily large friction in comparison with Zdol4000 and Z03, while Zdol4000 was slightly larger than Z03. The largest friction of Zdol2000 reveals that the 2-nm-thick Zdol2000 formed a monolayer that served as an immobile layer. With the increase in film thickness, the friction force of Zdol2000 decreased, indicating that extra lubricant molecules served as a mobile layer, while that of Z03 remained unchanged as the lowest value. By extrapolating the loading force versus friction force relationship into a negative loading force region, it is found that the friction force of Z03 tended to zero at zero net load (loading force plus adhesion force), while those for Zdol2000 and Zdol4000 exhibited finite values, indicating formation of an immobile layer, which shows similar characteristics to those of adhesive rubber material. The dewetted surface is found to feature violently changing friction force only at the first stage of sliding, and it then becomes stable after several sliding passes.     

Metal electrodes bonded on solid polymer electrolyte membranes (SPE)—II. The polarization resistance of Pt-Nafion electrode

The hydrogen and oxygen electrode reactions were examined on a Pt-SPE (Nafion) electrode with the condition that the platinum side was in contact with gaseous phase. The polarization curve shows an Ohmic relation determined mainly by the solution and membrane resistances. The removal of the solution resistance improves the above polarization characteristics to a large extent.     

Shape-controlled synthesis of nanocarbons from resorcinol-formaldehyde nanopolymers using surfactant-templated vesicular assemblies

The NaOH-catalyzed polymerization of resorcinol (R) and formaldehyde (F) confined to the vesicular assemblies of cetyltrimethylammonium bromide as a core template mixed with 1,3,5-trimethylbenzene and tert-butanol (tBuOH) as cosurfactants yielded RF polymer/cetyltrimethylammonium composite nanowires and nanospheres depending on the amount of tBuOH. Carbonization of the resulting nanpolymers led to microporous carbon nanowires of 45-240 nm diameter and nanospheres of 260-650 nm diameter. Similar but a little modified reactions successfully resulted in monodispersed carbon nanospheres of ca. 280 nm diameter as well as monodispersed carbon nanowires of ca. 70 nm diameter with a high surface area of 1777 m²/g. The present approach could be further extended to the synthesis of a wide range of carbon nanomaterials by using various surfactants and cosurfactants.     

Laser and tandem scanning confocal microscopic studies of rabbit corneal wound healing

The process of corneal endothelial wound healing was studied using laser and tandem scanning confocal microscopy (LSCM and TSCM). Following transcorneal freeze (TCF) injury, rabbit corneas were observed using ex vivo LSCM and in vivo TSCM. LSCM revealed the intracellular actin filament organization which, stained with phalloidin-FITC, in migrating endothelial cells, transformed fibroblast-like cells, stroma keratocytes, and epithelial cells during wound healing in corneal tissue. The TSCM provided sequential spatial observation of morphologic changes from endothelium to epithelium of the cornea during in vivo cellular repair of wound healing noninvasively on the same cornea without animal sacrifice. Ex vivo LSCM supported the morphologic analysis of the in vivo TSCM observations.     

Particle erosion behaviour of boiler tube materials at elevated temperature

The particle erosion behaviour of typical boiler tube materials, including carbon steel, low alloy steels and austenitic steels, at elevated temperatures up to 650 °C was studied using irregularly shaped silica particles. Using 304 steel, the influence of various factors, namely particle concentration, velocity and impingement angle, was examined. The erosion behaviour did not seem to differ significantly from that obtained at room temperature. The erosion rate was a linear function of the particle concentration. The velocity exponents obtained at 300 and 650 °C were both approximately 2.8. The peak impingement angle was at acute angles of 20° – 30°, with a tendency for the peak angle to be slightly higher at 300 °C than at 650 °C. However, the temperature effect was clearly observed in that the erosion rate at acute impingement angles increased significantly with the temperature suggesting that the steel tends to show a behaviour more typical of ductile materials as the temperature is increased. The erosion morphologies at low angles indicated cutting for every temperature used and the lengths of the cutting tracks obtained at 20° also increased with temperature.The erosion rate varied significantly between materials, e.g. the alloy (Incoloy) 800 eroded the most and the 12Cr-1Mo-V steel eroded the least at every temperature used, although every material showed an increase in the erosion rate with temperature. From an attempt to compare the erosion rate data obtained at 20° for every material at every temperature with the tensile properties of the steels, it was found that the yield strength of materials correlates reasonably well with the erosion rate. The erosion rate was apparently proportional to the reciprocal of the yield strength, suggesting that the flow stress included in Finnie's cutting theory may be conveniently substituted by the yield strength multiplied by a constant.