Permeation of Zidovudine and Probenecid from Oily Bases Containing Alcohols Through Rat Skin

Permeation of zidovudine (3'-azido-3'-deoxythymidine, AZT) and probenecid from oily bases containing an alcohol through rat skin was examined. Isopropyl myristate (IPM), as an oily vehicle, showed a penetration enhancing effect for AZT and probenecid. Ethanol, n-propanol, and n-butanol were used as additives in IPM and were examined for their own permeation and the enhancing effect on the permeation of AZT and probenecid. The skin permeation of AZT and probenecid from IPM was enhanced by addition of the alcohol in IPM. The degree of the enhancement was decreased with increasing lipophilicity of the alcohol used. me permeation rate of the drug from those systems was shown to be governed by penetration-enhancing effects of the oily base and alcohol, and the penetration of the alcohol itself through the skin.     

Safety evaluation on the depressurization accident in the gas turbine high temperature reactor (GTHTR300)

Japan Atomic Energy Agency has been developing a gas turbine high temperature reactor (GTHTR300) with electric power of approximately 300 MW. One of the unique safety design concepts of this system is that events with frequency of occurrence of higher than 10⁻⁸/reactor-year are evaluated as design basis events in order to show that the frequency of large amount of FP release is less than 10⁻⁸/reactor-year. According to this concept, a depressurization accident by a large break of helium piping is postulated as a design basis event. This accident is one of the most serious accidents in the high-temperature gas-cooled reactors from the viewpoint of loss of coolability. The safety evaluation on the accident was conducted based on the actual design of the system. The short-term and long-term behaviors of fuel temperature after occurrence of the accident, internal pressure of the reactor building, oxidation behavior of fuels and graphite structures were evaluated and exposure dose of general public was also estimated using the results of evaluation of fuel temperature and fuel failure by oxidation. All of the evaluation results meet the safety criteria and feasibility of the GTHTR300 was shown by this study.     

Theory and characteristics of novel variable reluctance 1X resolver

Although brushless resolvers have been used widely as angular position transducers, they are expensive due to their intricate construction, involving a rotary transformer to supply the exciting coils wound on the rotor poles with the current. It is shown theoretically in this paper that the resolver without rotary transformer or brushes can be realized by simple construction, which consists of the stator core with both 4-poles exciting windings and 2-poles output ones and the rotor core carrying no windings. In this resolver the rotor core has minimum gap at one side and a maximum gap at another side of the diameter. It is characterized by an outer surface form that makes the fluctuation part of gap permeance very in proportion to cos θ, where θ represents the angular position of a point in the air gap with respect to the origin on the rotor, the point of minimum air gap. The method determining the rotor form to embody the aforementioned gap permeance variation is also shown. It has been confirmed not only by simulation but also experiment that the 2-phase output voltages of a model designed based on the theory have sinusoidal waveforms with very small harmonic contents. Moreover, the rotor position detected by processing the output voltages through the conventional resolver/digital converter was within acceptable engineering accuracy.     

Transdermal Absorption of Zidovudine from Ethanol-Isopropyl Myristate Mixed System and Influence of Probenecid on It in Rats

Transdermal absorption of zidovudine (AZT) from an ethanol-isopropyl myristate (IPM) mixed system was examined in rats. For comparison of bioavailability (BA) after topical applications, 0.25 ml of the ethanol/IPM system containing 40% ethanol and 60 mM AZT was applied as a standard formulation. Values of the area under the plasma concentration-time curves of AZT for 8 hr (AUC_0-8), as indices of BA, following application of various formulations were compared with that of the standard formulation. Then the influence of content of the drug and ethanol, and application volume of the system was evaluated. BA was effectively improved only when the total amount of ethanol applied on the skin was increased. On the other hand, simultaneous transdermal application of AZT and probenecid increased the AU_0-8, of AZT without necessitating the increase in ethanol content in the formulation. In addition, coadministered probenecid improved cerebrospinal fluid/plasma concentration ratio of AZT.     

ORBIT: A parallel computing model of Prolog

This paper proposes a parallel processing model of the Prolog language. The model modifies Or-parallelism by introducing the “process bundle” as a candidate for simultaneous execution. The Process bundle is a subset of backtrack points stacked in depth-first execution. The process bundle includes one or more backtrack points, so it provides a longer process life cycle than the Or-parallel process. A process bundle is dispatched when an idle processor requests a job from an executing processor. The executing processor dispatches a message containing the full environment by which the idle processor can execute the process without any communication with other processors.     

Leak-tightness characteristics concerning the containment structures of the HTTR

The containment structures of the HTTR consist of the reactor containment vessel, the service area, and the emergency air purification system, which minimise the release of fission products in postulated accidents, which lead to fission product release from the reactor facilities. The reactor containment vessel is designed to withstand the temperature and pressure transients and to be leak-tight in the case of a rupture of the primary concentric hot-gas duct, etc. The pressure inside the service area is maintained at a negative pressure by the emergency air purification system. The emergency air purification system will also remove airborne radioactivity and will maintain a correct pressure in the service area.The leak-tightness characteristics of the containment structures are described in this paper. The measured leakage rates of the reactor containment vessel were enough less than the specified leakage limit of 0.1%/d confirmed during the commissioning tests and annual inspections. The service area was kept in a way that the design pressure becomes well below its allowable limitation by the emergency air purification system, which filters efficiency of particle removal and iodine removal well over the limited values.The obtained data demonstrate that the reactor containment structures were fabricated to minimise the release of fission products in the postulated accidents with fission product release from the reactor facilities.     

Safety design

JAERI established the safety design philosophy of the HTTR based on that of current reactors such as LWR in Japan, considering inherent safety features of the HTTR. The strategy of defense in depth was implemented so that the safety engineering functions such as control of reactivity, removal of residual heat and confinement of fission products shall be well performed to ensure safety. However, unlike the LWR, the inherent design features of the high-temperature gas-cooled reactor (HTGR) enables the HTTR meet stringent regulatory criteria without much dependence on active safety systems. On the other hand, the safety in an accident typical to the HTGR such as the depressurization accident initiated by a primary pipe rupture shall be ensured. The safety design philosophy of the HTTR considers these unique features appropriately and is expected to be the basis for future Japanese HTGRs.This paper describes the safety design philosophy and safety evaluation procedure of the HTTR especially focusing on unique considerations to the HTTR. Also, experiences obtained from an HTTR safety review and R&D needs for establishing the safety philosophy for the future HTGRs are reported.     

Influence of variations in creep curve on creep behavior of a high-temperature structure

It is one of the key issues for a high-temperature structural design guideline to evaluate the influence of variations in creep curve on the creep behavior of a high-temperature structure. In the present paper, a comparative evaluation was made to clarify such influence.The evaluation results showed that, in almost all cases of a creep behavior pattern in which creep strain accumulated during a stress cycle caused significant relaxation of the corresponding deformation-controlled stress in the following cycles, the variations in creep behavior with the creep curve were qualitatively similar to those in fundamental creep properties. On the other hand, in many cases of another creep behavior pattern in which creep strain accumulated during a cycle doesn't cause the significant stress-relaxation in the following cycles, the variations in creep behavior for earlier cycles are different from those in fundamental creep properties. Even in these cases, however, those get qualitatively similar after several cycles when their stress-time histories are stabilized.Additional consideration was given to the influence of the relationship between creep rupture life and minimum creep rate, i.e., the Monkman-Grant's relationship, on the creep damage evaluation.The consideration suggested that the Monkman-Grant's relationship be taken into account in evaluating the creep damage behavior, especially the creep damage variations. However, it was clarified that the application of the creep damage evaluation rule of ASME B.&P.V. Code Case N-47 to the “standard case”which was predicted from the average creep property would predict the creep damage on the safe side.     

Lateral Inhomogeneity in the Electronic Structure of a Conjugated Poly(3‐hexylthiophene) Thin Film

How annealing influences the morphology of a highly regioregular poly(3‐hexylthiophene) (RR‐P3HT) film at the substrate interface as well as the lateral inhomogeneity in the electronic structure of the film are elucidated. Whereas previous studies have reported that high‐molecular‐weight (MW) RR‐P3HT films tend to show low crystallinity even after annealing, it is found that high‐MW RR‐P3HT does show high crystallinity after annealing at high temperature for a long time. Photoemission electron microscopy (PEEM), X‐ray photoemission spectroscopy, and ultraviolet photoemission spectroscopy results clearly resolve a considerable lateral inhomogeneity in the morphology of RR‐P3HT film, which results in a variation of the electronic structure depending on the local crystallinity. The PEEM results show how annealing facilitates crystal growth in a high‐MW RR‐P3HT film.     

Use of support vector regression and numerically predicted cloudiness to forecast power output of a photovoltaic power plant in Kitakyushu,Japan

The development of a methodology to forecast accurately the power produced by photovoltaic systems can be an important tool for the dissemination and integration of such systems on the public electricity grids. Thus, the objective of this study was to forecast the power production of a 1‐MW photovoltaic power plant in Kitakyushu, Japan, using a new methodology based on support vector machines and on the use of several numerically predicted weather variables, including cloudiness. Hourly forecasts of the power produced for 1 year were carried out. Moreover, the effect of the use of numerically predicted cloudiness on the quality of the forecasts was also investigated. The forecasts of power production obtained with the proposed methodology had a root mean square error of 0.0948 MW h and a mean absolute error of 0.058 MW h. It was also found that the forecast and measured values of power production had a good level of correlation varying from 0.8 to 0.88 according to the season of the year. Finally, the use of numerically predicted cloudiness had an important role in the accuracy of the forecasts, and when cloudiness was not used, the root mean square error of the forecasts increased more than 32%, and the mean absolute error increased more than 42%. Copyright © 2011 John Wiley & Sons, Ltd.