High temperature electrochemical heat pump using water gas shift reaction. Part I: Theoretical considerations

A new electrochemical heat pump using a combination of an electrolytic reaction at lower temperature to absorb low grade thermal energy and a thermochemical reaction at higher temperature to produce more efficient thermal energy is proposed. At a lower temperature, an endothermic reaction which cannot occur thermochemically proceeds with electrolysis. At a higher temperature, an exothermic reaction which is the reverse of the electrolysis reaction occurs thermochemically to produce high grade thermal energy. The water gas shift reaction, CO₂(g) + H₂(g) CO(g) + H₂O(g), in molten carbonate is one possible candidate for the new electrochemical heat pump and can lead to an increase in the temperature of the thermal energy from 1100 to 1200K. A heat pump system using the shift reaction is also considered theoretically.     

Potential reprocessing improvements in the Advanced Fuel Recycle System

From the aspects of economical competitiveness, proliferation resistance, and minimizing waste problems, PNC has proposed an improved recycle concept for the FBR fuel cycle, termed Advanced Fuel Recycle System. Reprocessing in this system is based on the well-known PUREX flowsheet and features a “single cycle Pu/U co-extraction flowsheet” with lower decontamination factor (DF) than that in the conventional process. This feature is practical because of the FBR's low neutronic sensitivity to impurities.

Such a simplified extraction process without purification cycles should substantially reduce not only the number of process components but also the quantities of liquid to be treated in other related processes, so it will lead to the proportional reduction in waste processing, waste itself, and all other related equipments and facilities. This should improve overall economics. One method being examined to further reduce the liquid throughputs and simplify the process is to apply the crystallization technique to dissolver solution.

Overall, with this proposed concept, proliferation resistance will be significantly improved because plutonium is always recovered as a mixture with the uranium and DF of the plutonium product is low.

Reprocessing and fabrication processes are integrated into one fuel cycle plant in this system further contributing to these improvements.     

A quicker preparation method for autologous fibrin glue

To establish a quicker preparation procedure for cryoprecipitate (Cryo) from a patient's autologous plasma, to be used as fibrin glue, we examined the effects of various conditions on the concentrations and yields of coagulation factors in Cryo. Human plasma from healthy volunteers was divided and treated under various freezing, shaking and defrosting conditions. The concentrations of fibrinogen, plasminogen, fibronectin, and factor XIII in Cryo were then measured. Results were as follows: (1) concentrations and yields of plasma components in Cryo obtained from plasma stored at -20 degrees C were significantly higher than those in Cryo from plasma stored at -80 degrees C; (2) shaking at 70 cycles/min during the freezing process had a favorable effect on the concentrations and yields of coagulation factors in the Cryo; (3) a shaking thaw process in a cold water bath was a rapid method for obtaining adequate yields of coagulation factors; (4) shaking in the defrosting process did not affect the yields of coagulation factors. These results indicated that Cryo containing high concentrations of coagulation factors could be prepared easily and rapidly from a patient's autologous plasma (within 4-5 h).     

Factors affecting the oxidative activity of laccase towards biphenyl derivatives in homogeneous aqueous-organic systems

Catalytic oxidation of biphenyl derivatives was investigated using laccase in a homogeneous aqueous-organic system. A thermostable laccase from Trametes sp. showed the highest catalytic activity for the oxidation of 4-hydroxybiphenyl (4-HB) at a reaction temperature of 60 degrees C when dimethylsulfoxide (DMSO) was employed as a co-solvent. Furthermore, the catalytic performance was successfully enhanced by the incorporation of a laccase mediator system (LMS) into the aqueous-DMSO media. The catalytic performance strongly depended on the type of mediator, and the highest activity was observed with 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as mediator, suggesting the importance of the selection of a suitable mediator. It was verified that this mediator system is applicable to the oxidation of several biphenyl derivatives with hydroxyl groups.     

Disintegration process of yttria-stabilized zirconia ceramics using hydrothermal conditions

Capability of the recycling of high strength and high fracture toughness yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) sintered body utilizing “low-temperature annealing degradation” phenomenon was investigated. Hydrothermal treatment was employed to induce the phase transformation from tetragonal to monoclinic zirconia and to disintegrate the Y-TZP sintered body. 3 mol% Y₂O₃–ZrO₂ specimens sintered at 1,550 °C and more were disintegrated without leaving the original appearances when the treatment temperature was between 200 °C and 400 °C. The size of the disintegrated fragments of Y-TZP sintered body was much affected by hydrothermal treatment conditions. Only with hydrothermal treatment and simple ball milling, the sintered body was pulverized into the primary particle level. This technique is expected to apply to a sustainable recycling system for the zirconia ceramics, which restrains an energy consumption compared to crushing zirconia using mechanical procedures.     

Flexible feature discovery and structural information control

In this paper, we propose a new information theoretic method called structural information control for flexible feature discovery. The new method has three distinctive characteristics, which traditional competitive learning fails to offer. First, the new method can directly control competitive unit activation patterns, whereas traditional competitive learning does not have any means to control them. Thus, with the new method, it is possible to extract salient features not discovered by traditional methods. Second, competitive units compete witheach other by maximizing their information content about input patterns. Consequently, this information maximization makes it possible to control flexibly competition processes. Third, in structural information control, it is possible to define many different kinds of information content, and we can choose a specific type of information according to a given objective. When applied to competitive learning, structural information can be used to control the number of dead or spare units, and to extract macro as well as micro features of input patterns in explicit ways. We first applied this method to simple pattern classification to demonstrate that information can be controlled and that different neuron firing patterns can be generated. Second, a dipole problem was used to show that structural information could provide representations similar to those by the conventional competitive learning methods. Finally, we applied the method to a language acquisition problem in which networks must flexibly discover some linguistic rules by changing structural information. Especially, we attempted to examine the effect of the information parameter to control the number of dead neurons, and thus to examine how macro and micro features in input patterns can explicitly be discovered by structural information.     

The influence of matrix on the quantum size effect of CdSe microcrystals-doped thin films

CdSe microcrystals were successfully dispersed in GeO₂ glass andCaF₂ crystal thin films by rf-sputtering. All films preparedshowed the blue shift of absorption edge in visible spectra due toquantum size effect. The amount of the blue shift of the filmsincreased with decreasing the size of the microcrystals. Comparingthe amount of the particle size–depending blue shift of CdSemicrocrystals dispersed in between the GeO₂, CaF₂ and SiO₂ matricies, the influence of the matrix on the shift was found.Therefore, it can be said that there is an influence of the matrix onthe quantum size effect. From the modified theoretical calculation,the influence of matrix was considered to appear through Coulombinteraction between electrons and holes.