Construction of a geothermal power generation model based on characteristics of geothermal steam wells and its applications

Electricity generation in geothermal power plants depends on the characteristics of geothermal steam wells. In this research, a geothermal power generation model was constructed based on the characteristics of the steam well, and the generation of electricity was estimated precisely by the constructed model. Many applications of the geothermal power generation model are introduced. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(3): 39–49, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10039     

Creutzfeldt-Jakob disease associated with autonomic nervous system dysfunction in the early stage

A 54-year-old man presented with tremor and unusual behavior. He was admitted two months later because of dementia and myoclonus. Periodic synchronous discharges were observed on the electroencephalogram. Based on these findings, we diagnosed the case as Creutzfeldt-Jakob disease. About two weeks after admission, decubitus, bowel dysfunction and hypohidrosis occurred. We observed various autonomic nervous system dysfunctions such as abnormal pupillary response to autonomic drugs, reduced coefficient of variation of R-R interval, and abnormal diurnal blood pressure variation.     

Preparation of oxidized 6-O-glycolchitosan,pH sensitivity of its aqueous solution and of its cross-linked hydrogel

Chitosan and 6-O-glycolchitosan, a water-soluble chitosan derivative, were oxidized by periodate. In the case of chitosan, only degradation products were obtained. With 6-O-glycolchitosan, however, water-soluble amphoteric polyelectrolyte derivatives of chitosan having higher molecular weight were obtained. The oxidized 6-O-glycolchitosan (OX-GC) showed a pH sensitive change of viscosity in aqueous solution. Moreover, the OX-GC hydrogel, cross-linked with glutaraldehyde, showed a pH sensitive swelling behavior. The OX-GC showed biodegradation behavior by lysozyme after acetylation.     

Lightweight type linear induction motor and its characteristics

At the Institute for Posts and Telecommunications Policy, a postal transportation system has been studied. This system would make use of linear induction motor (LIM)-driven vehicles for transporting mail between post offices in the Tokyo Metropolitan area. The system would connect the main post offices in the Tokyo area with tunnels circularly constructed underground and would transport mail with linear induction motor-driven vehicles. In this study, it is found that if vehicle weight is reduced, climbing capability could be considerably improved. Accordingly, the potential for reducing the weight of vehicle-mounted LIMs has been explored, and a prototype lightweight LIM has been manufactured. This paper reports on the lightweight LIM and its characteristics.     

Electrical Properties of Manganese-Doped Titanium Dioxide

The electrical conductivity and Seebeck coefficient for TiO₂ doped with varying amounts of MnO₂ have been measured over the temperature range of 900°–1100°C. The Hall coefficient was also measured over the temperature range of 300°–500°C. The electrical conductivity and carrier density were found to decrease initially, go through a minimum at approximately x = 0.0001–0.001, and then increase with increasing content of MnO. For dopant levels above 0.01 at.%, p -type electrical conduction behavior was observed.     

TGF-beta1 influences early gingival wound healing in rats: an immunohistochemical evaluation of stromal remodelling by extracellular matrix molecules and PCNA

The effect of topically applied transforming growth factor beta1 (TGF-beta1) on the rat gingival wound healing process after flap surgery was evaluated by immunohistochemistry for extracellular matrix molecules (ECM), such as tenascin, heparan sulfate proteoglycan (HSPG) and type IV collagen, and for proliferating cell nuclear antigen (PCNA) in fibroblasts. TGF-beta1 solution was applied to the surgical wound experimental sites. Two microg/microl were applied at the time of the operation, and 1 microg/microl at days 1 and 2 after surgery, with contralateral control sites receiving the vehicle alone. Periodontal tissues were histologically examined at 3 and 7 days post-surgery. Tenascin was found to be more strongly stained in the granulation tissue from experimental sites at 3 days post-surgery. At 7 days postsurgery, HSPG-positive areas in granulation tissue had become smaller and there was a prominent proliferation of PCNA-positive fibroblast-like cells and type IV collagen-positive blood vessels. These results suggest that TGF-beta1 applied to surgical wounds influences early proliferation of gingival fibroblast-like cells, the formation of blood vessels, and ECM remodelling. In conclusion, TGF-beta1 application appears to promote granulation tissue formation in periodontal wound healing.     

A multi‐user CDMA receiver utilizing decorrelating detector with additional dummy pilot response

A pilot assisted CDMA system which uses extended spreading sequences with guard sequences under a quasi‐synchronous condition is capable of separating the interference components included in the input of a de‐correlating receiver by solving a system of linear equations. The performance of such a system, however, depends on the property of the de‐correlating matrix consisting of the received pilots, which correspond to the respective user spreading sequences and the multi‐path channel conditions. That is, the regularity of the matrix often tends to degrade, and the rank reduces occasionally primarily due to the multi‐paths, resulting in solutions that are vulnerable to AWGN. The present paper proposes an effective technique to solve this problem by introducing a virtual user into a group of real users that are to be served. The simulation results indicate a remarkable improvement in the bit‐error‐rate (BER) performance. In addition, based on the BER performance, the system has a RAKE‐like function that has power‐sum characteristics. Copyright © 2003 John Wiley & Sons, Ltd.     

Psychological evaluations of robot motions

Human arm motions were simulated using both computer graphics and an industrial robot under various velocity patterns, and evaluated to examine which factors are essential for human-likeness. The results are summarized as follows. First, the velocity peak position in the normalized movement time of the motion is important for the emotion of human-likeness. Second, the maximum value of the velocity affects the human impression of the motion. There exists an appropriate maximum value which best gives a subject the impression of human-likeness. Finally, the emotion of human-likeness is related to that of agreeableness. These results are almost the same for both a simulated motion on CRT and a robot motion.

Relevance to industry

In the future, robots will play important roles by assisting or cooperating with humans in various industrial fields. In such cases, a robot's motion must be well designed taking into account human perception. The results of the research will become an important guide for the design of a robot's motion.     

Origin of ZnO Varistor

The varistor properties were examined in porous ZnO. The sample used contained no dopants such as Bi₂O₃ or Pr₆O₁₁, which are usually considered to be useful in developing varistors. Comparison of I-V curves for the oxidized and unoxidized samples indicated that oxygen, which had chemisorbed and diffused into the grain boundary, played a role in developing varistor characteristics.     

Improved optical and electrical characteristics of free-standing GaN substrates by chemical polishing utilizing photo-electrochemical method

The optical and electrical properties of GaN(0001) surfaces treated by a novel chemical polishing method are described. Scanning microscopic photoluminescence images reveal that the polished GaN surface shows improved luminescence properties compared to the untreated surface. Current-voltage measurements of Schottky barriers formed using the GaN substrates show that the polished GaN surface has a lower reverse leakage current, and that the barrier height and ideality factor are improved after the polishing treatment.