Recycling of fiber reinforced plastics using depolymerization by solvothermal reaction with catalyst

Fiber reinforced plastics (FRP) have been widely used as a high strength material. However, it is well known that the FRP is one of the most difficult materials to fractionate into elemental components, namely fiber, filler, and polymers in the waste recycling process. Therefore, the wastes are treated in the incineration or landfilling without any recycling approaches. We have developed a new recycling method using subcritical fluids where unsaturated polyester (UP) resin in FRP can be efficiently depolymerized to separate glass fiber from filler and polymer. Reactions were carried out with or without a catalyst (K₃PO₄) in diethyleneglycol monomethylethter (DGMM) and benzyl alcohol under their subcritical state at temperatures 463–623 K for 1–8 h in a batch reactor. The conversion of UP became fast as the catalyst/solvent molar ratio increased and it was enhanced in the presence of K₃PO₄ catalyst in subcritical BZA. The glass fiber recovered after the FRP treatment in subcritical BZA was relatively long, while it became short and somewhat damaged at temperature higher than 573 K. The similar trend was observed when DGMM was used as a solvent.     

Non-binding property of cathepsin L to myosin

Disodium pyrophosphate at 10 mM concentration, was effective in dissociating myosin and actin from actomyosin in walleye pollock (Theragra chalcogramma) surimi and red bulleye (Priacanthus macracanthus) surimi. After Sepharose 2B gel filtration, cathepsin L contained in the actomyosin was obviously non-binding to myosin. Actomyosin from carp (Cyprinus carpio) muscle was not dissociated in pyrophosphate solution in the absence of MgCl₂ and it was successfully dissociated by 10 mM pyrophosphate in the presence of 2 mM MgCl₂. Cathepsin L in carp actomyosin was shown to be much more complicated than that in the above two surimis. After Sepharose 2B gel filtration, there were two activity peaks of cathepsin L in carp, one almost corresponding with actomyosin, the other obviously separated from actomyosin. Both of the peaks were non-binding to myosin.     

Applicability of clinker ash as fill material in steel strip-reinforced soil walls

The generation of coal ash by coal-fired thermal power plants has increased in recent years. This study focuses on the use of a type of coal ash, clinker ash, in place of sandy soil as a fill material in soil structures. Clinker ash is an excellent geomaterial to use as backfill for soil structures because it is lightweight and has high shear strength and permeability. In this study, to determine the applicability of clinker ash as a backfill material for steel strip-reinforced soil walls, a series of laboratory pullout tests was conducted on different types of clinker ash to investigate the pullout behaviour of a ribbed strip from a layer of clinker ash and to evaluate the influence of the overburden pressure and the degree of compaction on the maximum pullout resistance. The correlation between the physical properties of clinker ash and the maximum pullout resistance was investigated on the basis of the test results. Additionally, the results of the pullout tests were compared with those of in-situ pullout tests. Furthermore, the usefulness of clinker ash was evaluated by applying the pullout test results to the standard design method for reinforced soil walls and comparing the results with the material constants for commonly used sandy soil. The main conclusions of the study are as follows: (1) The tests performed here confirmed that clinker ash has excellent frictional properties compared with sandy soil. (2) The frictional properties of clinker ash exceed the proposed design values given in the manual describing the reinforced soil wall method. (3) The application of clinker ash in reinforced soil walls is effective from the viewpoint of frictional properties.     

Effect of Fluidizing Particle on Drying Characteristics of Porous Materials in Superheated Steam Fluidized Bed under Reduced Pressure

The hygroscopic porous particle was used as the fluidizing particle for the superheated steam fluidized bed drying under reduced pressure. A relatively large material was immersed in the fluidized bed as the drying sample. The drying characteristics of the sample were examined experimentally and the results were compared with those in the case of inert particle fluidized bed.

The water transfer from the sample to the fluidizing particle bed in the case of hygroscopic porous particle facilitated the drying regardless of pressure and temperature in the drying chamber. The increment degree of the sample temperature at the earlier period of drying was smaller in the case of hygroscopic porous particle than in the case of inert particle, and the phenomenon was more remarkable in the case of superheated steam than in the case of hot air.     

Compensation for magnetizing inrush currents in transformers using a PWM inverter

When a transformer is connected to a circuit, under certain conditions, magnetizing inrush currents may be about ten times the full load current of the transformer. The currents contain a large amount of harmonic components and cause some relays to trip out. In this paper, the magnetizing inrush currents are compensated using a PWM inverter. The magnetizing inrush currents are detected and the PWM inverter generates compensating currents for the inrush currents. Hysteresis current controllers are used for fast response. The validity of this compensation is investigated by the simulation results. In addition, hardware implementation for the compensator is accomplished to verify the simulation results. Moreover, for the compensator, the relation between the compensating characteristics, the maximum switching frequency, and the coupling reactor is discussed based on the simulation results. Finally, characteristics of two current controllers (hysteresis band current controller and ramp‐comparison controller) are compared and it is shown that the hysteresis band current controller is more suitable for the compensator. The PSCAD/EMTDC electromagnetic transient simulator is used for the simulations. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(2): 53–64, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10023     

Effect of Fluidizing Particle on Drying Characteristics of Porous Materials in Superheated Steam Fluidized Bed under Reduced Pressure

The hygroscopic porous particle was used as the fluidizing particle for the superheated steam fluidized bed drying under reduced pressure. A relatively large material was immersed in the fluidized bed as the drying sample. The drying characteristics of the sample were examined experimentally and the results were compared with those in the case of inert particle fluidized bed.

The water transfer from the sample to the fluidizing particle bed in the case of hygroscopic porous particle facilitated the drying regardless of pressure and temperature in the drying chamber. The increment degree of the sample temperature at the earlier period of drying was smaller in the case of hygroscopic porous particle than in the case of inert particle, and the phenomenon was more remarkable in the case of superheated steam than in the case of hot air.     

Molecular biological analysis of microflora in a garbage treatment process under thermoacidophilic conditions

In our efforts to solve problems associated with the treatment of garbage wastes, a novel, efficient process utilizing a small bioreactor equipped with a heating and an agitating apparatus was developed. The use of this process, which reduces and stabilizes garbage wastes, can be distinguished from other similar treatment processes that utilize similar equipment by its highly stable operation. This advantage led us to consider a characteristic microflora that would play an important role in the process. Thus, we analyzed the structure of the microflora in the process using molecular biological methods. The major microorganisms inhabiting the treatment environment were usually maintained for several weeks although garbage waste was added to the system each weekday. Moreover, surprisingly, lactic acid bacteria constituted a large majority in the microflorae in spite of the thermoacidophilic conditions in the reactor. These analyses permitted a better understanding of the mechanism of the process, especially of its stability.     

Participation of cysteine protease cathepsin L in the gel disintegration of red bulleye (Priacanthus macracanthus) surimi gel paste

BACKGROUND: Endogenous proteases, among them cysteine‐type proteases, are reported to contribute to gel disintegration, resulting in kamaboko of poor quality. Severe gel disintegration occurs in red bulleye surimi gel paste. The objective of this study was to clarify the participation of cysteine protease cathepsin L in the gel disintegration of red bulleye surimi. The surimi was made into kamaboko with and without cathepsin L inhibitors. To confirm its hydrolysis action, crude cathepsin L was also extracted and added to the surimi to make kamaboko. RESULTS: The gel strength of kamaboko obtained by both one‐step (50 °C, 2 h) and two‐step (50 °C, 2 h + 80 °C, 20 min) heating was very low in the absence of inhibitors. Protease inhibitors E‐64 and leupeptin were found to enhance the gel strength considerably. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the hydrolysis of kamaboko was promoted by crude cathepsin L and inhibited by E‐64 and leupeptin. The gel strength of two‐step heated kamaboko was increased from 12 to 110 and 130 g cm^?2 by E‐64 and leupeptin respectively at a concentration of 0.2 g kg^?1 surimi. CONCLUSION: Endogenous cathepsin L of red bulleye surimi participates in gel disintegration during kamaboko processing. It does so by degrading the myosin heavy chain of actomyosin and consequently hindering the gelation of red bulleye surimi. Copyright © 2009 Society of Chemical Industry