Experimental Study of Porous Gel Sintering

Formation and disappearance of closed pores in silica gel during sintering were experimentally detected using a light-scattering technique. The disappearance of closed pores is strongly influenced by the atmosphere in which the gel is sintered.     

A prolog based expert system for the allocation of quality assurance program resources

The worldwide proliferation of fraudulent materials has brought about the need for a new approach to the control of purchased material quality. Nuclear power, defense, aerospace and many other industries are affected by the supply of poor quality clones that presume to be original replacement parts. Safety considerations abound as these highly defective materials are used in systems that are critical to the preservation of human lives. Commonly utilized quality assurance programs have not effectively stopped the influx of fraudulent materials. These programs fail to concentrate inspection efforts on materials and inspection attributes that would effectively prevent the acceptance of fraudulent materials. herein a solution is presented to this problem in the form of an expert system application. Information commonly available in industry is formulated into a knowledge based system wherein advisories are given to the user regarding key purchased material receipt inspection strategies.     

Thermal storage efficiencies of two solar saltless water ponds

A comparative study between two types of solar ponds is presented. The first type has its free surface covered by a thin layer of transparent paraffin oil. The second type is covered by transparent glass floating devices. Each device disposes an air-vacuum chamber. The free water surface between these devices is covered by transparent paraffin oil also. The thermal storage efficiency of each pond is estimated during two time periods: between sunrise and sunset and from midnight to midnight. The calculated efficiency between sunrise and sunset corresponds to the average transmittance–absorptance product. This is estimated using linear regression and also a maximum likelihood identification technique. The behavior of the system was studied by solving numerically the heat transfer equations of the system. Also an ARMAX (AutoRegressivie Moving Average with eXogenous signal) model allowing the assessment of its performance was presented. This efficiency is larger for the first pond during the sunrise to sunset period and smaller when calculated from midnight to midnight. Thus, the first type of pond could be preferred for a use just after the sunset of the same day, while the second for use after one or more days of heat storage.     

Linearity stablized fiber-optic thermometer using pseudo-heterodyne phase detection

A temperature sensor using a fiber-optic Fabry-Perot interferometer is described. A pseudo-heterodyne detection scheme is adopted to read the light phase difference in the Fabry-Perot interference output. A higher harmonic components comparison method is used to stabilize the system and to increase detection linearity. This system realizes not only highly sensitive temperature sensing with good linearity and minimal adjusting error, but also application to the sensing of other physical quantities such as vibrations. Additionally, the signal-to-noise ratio and distortion of the detected signal are investigated as functions of fiber end reflectivity. These results will be useful in designing a high performance fiber-optic Fabry-Perot thermometer.     

Inference of message sequence charts

Software designers draw message sequence charts for early modeling of the individual behaviors they expect from the concurrent system under design. Can they be sure that precisely the behaviors they have described are realizable by some implementation of the components of the concurrent system? If so, can we automatically synthesize concurrent state machines realizing the given MSCs? If, on the other hand, other unspecified and possibly unwanted scenarios are "implied" by their MSCs, can the software designer be automatically warned and provided the implied MSCs? In this paper, we provide a framework in which all these questions are answered positively. We first describe the formal framework within which one can derive implied MSCs and then provide polynomial-time algorithms for implication, realizability, and synthesis.     

Quality-Assurance Technology in Japan

A survey of the state of SQA in Japan finds that the situation is much like, but slightly different than, that in the US.