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Hideyuki Tsukagoshi - One of the best experts on this subject based on the ideXlab platform.

  • a study on a sound Operated Valve for a wearable pneumatic system 1st report development of a pilot Valve of a sound Operated directional control Valve
    TRANSACTIONS OF THE JAPAN FLUID POWER SYSTEM SOCIETY, 2008
    Co-Authors: Shuyi Jing, Ato Kitagawa, Canghai Liu, Hideyuki Tsukagoshi
    Abstract:

    A sound Operated directional control Valve is proposed in order to widen the application of pneumatic drives to a multi-degree wearable system. The proposed Valve opens and closes in response to the sound of a specific frequency propagated inside the gas supply tube and therefore needs no electric wiring to convey the control signal. By using multi-frequency sound, several Valves can be controlled simultaneously and resultantly the pneumatic multi-degree wearable system can be constructed compactly. In this paper, firstly, the sound-gas pressure converter, which uses the resonance of a vibrating object consisting of a leaf spring and head, is proposed and is improved so that self-excited vibration does not arise. Secondly, the basic characteristic of the sound-gas pressure converter is investigated, and it is clarified that the back pressure is different depending on whether the sound of specific frequency exits or not. Furthermore, a pilot Valve of the sound Operated directional control Valve is developed by combining the sound-gas pressure converter with a vibration transmitting element, which transmits the vibration in the tube to the sound-gas pressure converter. Using a Dry-Ice Power Cell developed in a previous study as the portable gas supply, the characteristic of the developed pilot Valve is investigated experimentally. It is clarified that a definite change of back pressure of the pilot Valve in response to the sound inside the gas supply tube can be obtained, and it is concluded that the developed Valve can be used as a pilot Valve of a sound Operated directional control Valve.

  • a study on a sound Operated Valve for a wearable pneumatic system
    Proceedings of the JFPS International Symposium on Fluid Power, 2008
    Co-Authors: Ato Kitagawa, Shuyi Jing, Canghai Liu, Hideyuki Tsukagoshi
    Abstract:

    A sound Operated directional control Valve (SODC-Valve) is proposed which opens and closes in response to the sound of a specific frequency propagated inside the gas supply tube and therefore needs no electric wiring to convey the control signals. By using multi-frequency sound, several Valves can be controlled simultaneously and resultantly the pneumatic multi-degree wearable system can be constructed compactly. Firstly, the sound-gas pressure converter is proposed and improved so that self-excited vibration can be suppressed. Secondly, the basic characteristic of the sound-gas pressure converter is investigated to show that the back pressure is different depending on whether the sound of specific frequency is added or not. Furthermore, a pilot Valve is developed. Because the pilot pressure change of the pilot Valve developed is only 20kPa, a main Valve is proposed and developed. Finally, a pneumatic multi-degree-of-freedom wearable power-assist system is constructed by using a Dry Ice Power Cell as the portable gas supply, wearable actuators developed in the previous study, and two sound Operated directional control Valves developed. Experimental results show that the sound Operated directional control Valve is feasible and practical in the pneumatic multi-degree-of-freedom wearable system.

Jangbom Chai - One of the best experts on this subject based on the ideXlab platform.

  • DEVELOPMENT OF A MAJORITY VOTE DECISION MODULE FOR A SELF-DIAGNOSTIC MONITORING SYSTEM FOR AN AIR-Operated Valve SYSTEM
    Nuclear Engineering and Technology, 2015
    Co-Authors: Wooshik Kim, Jangbom Chai, Intaek Kim
    Abstract:

    Abstract A self-diagnostic monitoring system is a system that has the ability to measure various physical quantities such as temperature, pressure, or acceleration from sensors scattered over a mechanical system such as a power plant, in order to monitor its various states, and to make a decision about its health status. We have developed a self-diagnostic monitoring system for an air-Operated Valve system to be used in a nuclear power plant. In this study, we have tried to improve the self-diagnostic monitoring system to increase its reliability. We have implemented three different machine learning algorithms, i.e., logistic regression, an artificial neural network, and a support vector machine. After each algorithm performs the decision process independently, the decision-making module collects these individual decisions and makes a final decision using a majority vote scheme. With this, we performed some simulations and presented some of its results. The contribution of this study is that, by employing more robust and stable algorithms, each of the algorithms performs the recognition task more accurately. Moreover, by integrating these results and employing the majority vote scheme, we can make a definite decision, which makes the self-diagnostic monitoring system more reliable.

  • New algorithms for diagnosing defects of an air-Operated Valve for self diagnostic monitoring system
    2014 International Conference on Prognostics and Health Management, 2014
    Co-Authors: Wooshik Kim, Jangbom Chai
    Abstract:

    We have developed a self-diagnostic monitoring system for an air Operated Valve system which produces arrow patterns according to the states of the system and makes a diagnosis whenever the system shows the corresponding symptom [1, 2]. In our first model, we have used a neural network and a simple comparison method for decision processor. In this paper, we modify and improve the decision processor module. We developed a logistic regression algorithm for the simple decision algorithm and modified the neural network algorithm. By changing the rule for translating arrow symbols into 2-D tuples, we could make unambiguous and rich training data set. With this, we performed some simulations and present a result.

  • Condition Monitoring of a Motor-Operated Valve Using Estimated Motor Torque
    Jsme International Journal Series C-mechanical Systems Machine Elements and Manufacturing, 2004
    Co-Authors: Jangbom Chai, Shinchul Kang, Sung Keun Park, Sung-yull Hong
    Abstract:

    This paper is concerned with the development of data analysis methods to be used in on-line monitoring and diagnosis of Motor-Operated Valves (MOVs) effectively and accurately. The technique to be utilized includes the electrical measurements and signal processing to estimate electric torque of induction motors, which are attached to most of MOV systems. The estimated torque of an induction motor is compared with the directly measured torque using a torque cell in various loading conditions including the degraded voltage conditions to validate the estimating scheme. The accuracy of the estimating scheme is presented. The advantages of the estimated torque signatures are reviewed over the currently used ones such as the current signature and the power signature in several respects: accuracy, sensitivity, resolution and so on. Additionally, the estimated torque methods are suggested as a good way to monitor the conditions of MOVs with higher accuracy.

  • DETERMINATION OF COMPONENT MOTIONS IN A MOTOR-Operated Valve USING HOUSING VIBRATION☆
    Mechanical Systems and Signal Processing, 1996
    Co-Authors: Jangbom Chai, Richard H. Lyon
    Abstract:

    Abstract This paper is concerned with diagnosing the construction of motor Operated Valves (MOVs) based on their performance in previous runs. One part of the signature that reveals condition is Valve travel, which is to be determined non-invasively. The technique described here is based on the determination of Valve stem rotation through the analysis of gear meshing forces. These forces are, in turn, determined from the vibrations they produce in the MOV housing. These vibrations are interpreted as forces through inverse filtering of the received signals. The gear mesh force signals are, in turn, related to gear rotation through frequency demodulation. Experimental results from a laboratory set-up indicate that this procedure leads to acceptable estimates of shaft rotation and Valve travel.

Vijit Koshy Cherian - One of the best experts on this subject based on the ideXlab platform.

  • Reduction in left ventricular volume following aortic Valve replacement does not predict improved ventricular function
    Indian Journal of Thoracic and Cardiovascular Surgery, 2009
    Co-Authors: Alpha Mathew Kavunkal, Jayavelan Ramkumar, Shivananad Gangahanumaiah, Antonisamy Belavemdra, Vijit Koshy Cherian
    Abstract:

    Background Aortic Valve replacement in rheumatic disease is one of the procedures that clearly prolonged the life expectancy of adult patients. Our study objectives are to assess the mortality and morbidity associated with aortic Valve replacement, and study the effects of successful, Valve replacement on ventricular volume and performance in aortic stenosis and in aortic incompetence. Methods Between January 1997 and December 2001, 148 patients underwent aortic Valve replacement at our institution. The records of these patients were evaluated retrospectively. A total of 136 survivors were followed up both actively and passively. Results There were 9 deaths (6.07%) with an early mortality at 30 days of 4.05% and Valve related mortality of 4.05%. Bleeding events and Operated Valve endocarditis occurred infrequently (0.03% and 0.04% / patient year). 2 patients had nonstructural Valve dysfunction (paravalvular leak) (0.02% / patient year). Following successful Valve replacement, ventricular volume decreased substantially, while there was no significant increase in ventricular performance in aortic stenosis, and aortic incompetence. Conclusion Aortic Valve replacement can be performed today with a low mortality and morbidity. Although the ventricular volume and cardiac size reduced substantially following Valve replacement, the ventricular performance remained unchanged in aortic stenosis, and aortic incompetence because of the impaired ventricular function pre-operatively and because the ejection fraction tends to over estimate contractile function in aortic regurgitation. Low preoperative ejection fraction is therefore an important risk factor for postoperative left ventricular dysfunction.

Subrata Chatterjee - One of the best experts on this subject based on the ideXlab platform.

  • PLC based flow control system using a motor Operated Valve
    2018 4th International Conference on Control Automation and Robotics (ICCAR), 2018
    Co-Authors: Mandakinee Bandyopadhyay, Nirupama Mandal, Subrata Chatterjee
    Abstract:

    The motor Operated control Valve as a final control element in any process control loop of a process plant may be controlled according to the set point needed by the process requirement. There are various types of control techniques of a motorized Valve are presented by the different investigators. In the present paper, a Programmable Logic Controller (PLC) based flow control scheme using a motor [PMDC] Operated Valve has been described. The final calibration and experimental results reported in the paper reveal the linearity and reliability of the control system.

Richard D. Weisel - One of the best experts on this subject based on the ideXlab platform.

  • Guidelines for Reporting Morbidity and Mortality after Cardiac Valvular Operations
    The Annals of thoracic surgery, 1996
    Co-Authors: L. Henry Edmunds, Richard E. Clark, Lawrence H. Cohn, Gary L. Grunkemeier, D. Craig Miller, Richard D. Weisel
    Abstract:

    At the request of the Councils of The Society of Thoracic Surgeons (STS) and The American Association for Thoracic Surgery (AATS) the Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity "revisited" the "Guidelines" published in September 1988 [1–3]. The purpose of the review was to update and clarify definitions within the guidelines and to consider recommendations made by others [4, 5]. The variety of cardiac valvular procedures has expanded since 1988; therefore, in this document the term "Operated Valve" indicates prosthetic and bioprosthetic heart Valves of all types: Operated or repaired native Valves and allograft and autograft Valves . The term "Operated Valve" includes any cardiac Valve altered by a surgeon during an operation. Much morbidity and mortality is a direct consequence of the interaction between the patient and Operated Valve(s), although patient variables (eg, age, degree of coronary arterial disease, follow-up care) may be more responsible for outcomes than an Operated Valve. However, no set of guidelines can identify all possible patient factors that may affect morbidity and mortality. General agreement regarding the following definitions of terms and suggestions for reporting data do not preclude more detailed analyses or constructive recommendations and investigators are encouraged to identify relevant patient factors in addition to factors related to Operated Valves.