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Now showing items 1 - 16 of 35

  • INJECTION DEVICE AND POWER DEVICE PROVIDED WITH SAME

    The purpose of the present invention is to provide: an injection device that causes combustion by mixing water efficiently with engine fuel, and that can improve output; and a power device provided with the injection device. An injection device (2) injects a mixture of water and a catalyst into an intake manifold (12) that introduces air from an engine (1) into the combustion chamber (11), the engine producing power by causing a mixed gas of air and fuel to combust in a combustion chamber (11). The mixture of water and the catalyst is injected into air passing through the interior of the intake manifold (12) and is introduced into the combustion chamber (11) together with the air, and the foregoing makes it possible to achieve combustion in the combustion chamber (11) without causing separation of the fuel and water.
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  • Vertical Shaft Support Improvement Studies by Strata Grouting at Aquifer Zone

    Yu, Qing   Yin, Kexin   Ma, Jinrong   Shimada, Hideki  

    The shaft lining failure which occurs in deep alluvium is a sudden coal mine hazard. The strata grouting is one of the treatment methods for the shaft lining failure. To investigate the impact of grout injection pressure on the shaft lining, the field measurement and the numerical analysis of the shaft lining stress variation during the grouting were conducted. To improve the strata grouting, the underground continuous impervious curtain (UCIC) is proposed as a new method by using the chain conveyor cutter technique without the impact on the shaft lining. The effects of the new method were also analyzed by means of the numerical methods. The results show that the strata grouting in the deep alluvium needs a high injection pressure, and in the horizontal direction, the shaft lining sustains the repeat tensile and compressive force during the grouting process. The negative influence of strata grouting on the stability of the shaft lining is obvious and serious. The UCIC built around the shaft lining can restrain the stress concentration induced by the aquifer drawdown. The triangular UCIC has a similar effect as that of the vertical one, and the small angle is better for preventing the shaft lining failure.
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  • Vertical Shaft Support Improvement Studies by Strata Grouting at Aquifer Zone

    Yu, Qing   Yin, Kexin   Ma, Jinrong   Shimada, Hideki  

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  • Examination for Effectiveness of Scatter Correction in Portable Chest Radiography

    Ichikawa, Hajime   Ono, Takaaki   Sawane, Yasuhiro   Terabe, Mitsuaki   Yamaguchi, Minoru   Shimada, Hideki  

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  • Behaviour of grouting material used for floor reinforcement in underground mines

    Shimada, Hideki   Hamanaka, Akihiro   Sasaoka, Takashi   Matsui, Kikuo  

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  • Stability of Deep Underground Openings through Large Fault Zones in Argillaceous Rock

    Qian, Deyu   Zhang, Nong   Pan, Dongjiang   Xie, Zhengzheng   Shimada, Hideki   Wang, Yang   Zhang, Chenghao   Zhang, Nianchao  

    The stability of underground openings is pivotal to sustainable safe mining in underground coal mines. To determine the stability and tunneling safety issues in 800-m-deep underground openings through large fault zones in argillaceous rocks in the Guqiao Coal Mine in East China, the pilot industrial test, laboratory experimentation, and field measurements were used to analyze the large deformations and failure characteristics of the surrounding rock, the influence factors of safe excavation and stability of underground openings, and to study the stability control countermeasures. The main factors influencing the stability and tunneling safety include large fault zones, high in situ stress, poor mechanical properties and engineering performance of the argillaceous rock mass, groundwater inrush and gas outburst. According to the field study, the anchor-ability of cables and the groutability of cement-matrix materials in the argillaceous rock in the large fault zones were extremely poor, and deformations and failure of the surrounding rock were characterized by dramatic initial deformation, high long-term creep rate, obviously asymmetric deformations and failure, rebound of roof displacements, overall loosened deformations of deep surrounding rock on a large scale, and high sensitivity to engineering disturbance and water immersion. Various geo-hazards occurred during the pilot excavation, including roof collapse, groundwater inrush, and debris flow. Control techniques are proposed and should be adopted to ensure tunneling safety and to control the stability of deep underground openings through large fault zones, including regional strata reinforcement technique such as ground surface pre-grouting, primary enhanced control measures, floor grouting reinforcement technique, and secondary enclosed support measures for long-term stability, which are critical for ensuring the sustainable development of the coal mine.
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  • CORIOLIS FLOWMETER

    A drive device for operating an electromagnetic oscillator is formed by: an OP amplifier which amplifies an analog input signal from an electromagnetic pickoff; an A/D converter which converts the analog signal outputted from the OP amplifier into a digital signal; a D/A converter which performs a digital process on the digital signal outputted from the A/D converter in accordance with a phase detection in a DSP and converts the digital signal of the data amount into an analog signal; and a D/A converter which performs a digital process on the digital signal outputted from the D/A converter in accordance with a phase detection in the DSP and converts the digital signal of the data amount into an analog signal.
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  • TEMPERATURE MEASUREMENT CIRCUIT IN FLOWMETER

    A line-to-line resistance (24) is obtained by subtracting a resistance value, which is obtained by multiplying a voltage ratio based on divided voltages in a nonconductive state between a second electric line (26) and a third electric line (27) by a reference resistance, from a resistance value obtained by multiplying a voltage ratio based on divided voltages in a conductive state therebetween by the reference resistance. Obtaining the line-to-line resistance (24) allows a temperature-related, compensated resistance value to be obtained.
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  • Estimation of dynamic tensile strength of sandstone

    Kubota, Shiro   Ogata, Yuji   Wada, Yuji   Simangunsong, Ganda   Shimada, Hideki   Matsui, Kikuo  

    A series of dynamic tests on Kimachi sandstone for measuring dynamic tensile strength are carried out using underwater shock waves. An emulsion explosive is used as the source of dynamic loading, and a pipe filled with water was arranged between the explosive and a cylindrical specimen. The length of the pipe is varied to produce different strengths of the incidence shock wave into the specimen. The velocity at the free end of the specimen and the position of a crack are observed using a laser vibration meter and a high-speed camera, respectively. A simple method of estimating dynamic tensile strength is proposed based on experimental results. The complete velocity pro. le at the free end without fracture information is completely constructed under a simple assumption. The point at which the crack may be markedly activated has been defined by the velocity pro. le at the free end as "the averaged fracture point''. Instead of the distance from the free end to the fracture position, the distance from the free end to the averaged fracture point is employed in estimating dynamic tensile strength. The dynamic tensile strength of Kimachi sandstone was obtained by an improved method within strain rates of 10-40 s(-1). This study has indicated that the dynamic tensile strength varies with strain rate to the 1/3 power. (C) 2007 Elsevier Ltd. All rights reserved.
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  • Comparing blast-induced ground vibration models using ANN and empirical geomechanical relationships

    Iramina, Wilson Siguemasa   Sansone, Eduardo Cesar   Wichers, Michiel   Wahyudi, Sugeng   Eston, S=C3=A9rgio M=C3=A9dici de   Shimada, Hideki   Sasaoka, Takashi  

    Abstract Blasting remains as an economical and reliable excavation technique, but there are some environmental shortcomings such as the control of blast-induced vibration. The impacts of vibration over surrounding communities in a blast area have been investigated for decades and researchers have been using a myriad of empirical predictive attenuation equations. These models, however, may not have satisfactory accuracy, since parameters associated to geomechanical properties and geology affect the propagation of seismic waves, making vibration modeling a complex process. This study aims for application of an Artificial Neural Network (ANN) method and Geomechanical parameter relationships to simulate the blast-induced vibration for a Brazilian mining site and then compare them to the traditional approach. ANN had the best performance for this mine despite having demanded large datasets (as much as for the traditional approach), while geomechanical parameters like RQD and GSI may be used to deliver a fair approach even without seismic data. Also, ANN methods may be useful in dealing with a large amount of information to facilitate the simulation process when combined with other methods. Therefore, alternative prediction methods may be helpful for small budget mining operations in planning and controlling blast-induced vibration and helping mining in urban areas becoming a more sustainable activity.=09
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  • Study on Effect of Blast Vibration on Size of Fragmentation at Limestone Quarry

    SHIMADA, Hideki   MATSUI, Kikuo   ICHINOSE, Masatomo   SASAOKA, Takashi   KUBOTA, Shiro   M.SIMANGUNSONG, Ganda   OGATA, Yuji  

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  • Role of Acoustic Emission for Solving Rock Engineering Problems in Indonesian Underground Mining

    Kramadibrata, Suseno   Simangunsong, Ganda Marihot   Matsui, Kikuo   Shimada, Hideki  

    In situ stress measurement is not well accepted yet in Indonesia due to the unavailability of technology, high costs and because it is impractical in remote regions. Alternatively, the Kaiser effect of acoustic emission (AE) can be used as a method for determining the stress-state at depth, without creating induced stress and is practical in remote areas. This paper is focused on the development of the AE test. The research has started to study the phenomenon of stress memory in a rock sample, the factors influencing the phenomenon, and finally, to determine the in situ stresses around underground excavations by applying the AE method. It is expected that knowledge in gaining the most important input parameters for maintaining the stability of underground excavations can be well understood and be reliably conducted at a reasonable cost.
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  • Formation of Anodic Oxide Films on Aluminum in Diluted KOH Solutions.

    SHIMADA, Hideki   SAKAIRI, Masatoshi   TAKAHASHI, Hideaki  

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  • Efficiency analysis of thinning based on daily reports of forest operations:the case of Hiyoshi,Japan

    Shimada, Hideki   Fujino, Masaya   Kuriyama, Koichi  

    A new requirement has emerged to improve efficiency in forest management in Japan. However, few empirical studies assess the efficiency of forest management using data from several sites and examine long-term forest management. The objective of this research is to assess the efficiency of thinning by examining daily operational data on the districts in Hiyoshi provided by the Hiyoshi's Forest Owners' Cooperative. Using data envelopment analysis, we find that even within the same organization, differences can be seen among forest plots. In addition, from the econometric analysis, we find that efficiency significantly depends on natural conditions such as tree diameter at breast height or number of felled trees left in forests (rather than extracted). The results indicate that Hiyoshi's Forest Owners' Cooperative, which applies relatively advanced forest management, can still improve efficiency by working with trees with large enough diameters at breast height, implementing thinning that will lead to such larger diameters, and introducing an adequate machine that will decrease the number of felled trees left in forests.
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  • Rise of Breakdown Potential of Anodic Oxide Film on Aluminum by Pore-Filling Method.

    SHIMADA, Hideki   SAKAIRI, Masatoshi   TAKAHASHI, Hideaki  

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  • Effects of pH-Induced Changes in Soil Physical Characteristics on the Development of Soil Water Erosion

    Matsumoto, Shinji   Ogata, Shunta   Shimada, Hideki   Sasaoka, Takashi   Hamanaka, Akihiro   Kusuma, Ginting Jalu  

    Soil water erosion is frequently reported as serious problem in soils in Southeast Asia with tropical climates, and the variations in pH affect the development of the erosion. This study investigated the effects of changes in pH on soil water erosion based on changes in the physical properties of the simulated soils with pH adjusted from 2.0 to 10.0 through artificial rainfall tests. The zeta potential was entirely shifted to positive direction at each pH condition due to Al, Ca, and Mg. In the pH range of 6.0 to 2.0, the aggregation of soil particles resulting from the release of Al3+ from clay minerals and/or molecular attraction between soil particles caused the plastic index (I-P) of the soil to decrease. The decrease in IP led to the development of soil water erosion at the pH range. When the pH exceeded 6.0, the repulsive force generated by the negative charges on soil particles decreased IP, resulting in accelerated erosion by water. The results suggest that changes in pH causes physical properties of the soil to change through changes of the zeta potential in the clayey soil rich in Al, Ca, and Mg, leading to the development of soil water erosion.
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