• Title/Summary/Keyword: experimental device

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Experimental Study of Impulsive High Current Generating Apparatus (충격전류발생장치의 실험적연구)

  • An Kyun Kim
    • 전기의세계
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    • v.24 no.4
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    • pp.73-76
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    • 1975
  • In this study, a design scheme of an impulsive high current generating device is presented. The device is proved to be effective in producing rather complex type of the permanent magnet. Principally, the apparatus designed same to the ordinary potential transformer or current transformer, but, it has a certain differences that the primary winding of many turns is excited by d.c. source and the secondary winding of a few turns induce low voltage and high current at the instant when opening a switch in the primary circuit. This paper does not include magnet production process. Rather, it deals with the analytical studies of the devices, the designing procedure of the experimental setup, and some results from the experimental data are presented as a preliminary study. The experimental results are found to agree well with the theoritical analysis presented in this paper.

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Effect of Mouthrinses prepared by Sterilized Water-Generating Device on the Control of Periodontal Disease (살균수 발생장치에 의해 생성된 양치용액이 치주질환에 미치는 효과)

  • Lee, Ji-Hyun;Yun, Jeong-Ho;Choi, Seong-Ho;Cho, Kyoo-Sung
    • Journal of Periodontal and Implant Science
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    • v.34 no.3
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    • pp.659-669
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    • 2004
  • The aim of this study was to evaluate the clinical efficacy of mouthrinses prepared by sterilized water-generating $device(Purister^{(R)})$ on the control of gingivitis and incipient periodontitis when it was used as a adjunctives to the mechanical plaque control. 40 healthy patients with gingivitis or incipient periodontitis were divided into two groups. Patients in the experimental group use mouthrinses prepared by sterilized water-generating $device(Purister^{(R)})$ after tooth brushing while patients in the control group do only tooth brushing for plaque control. All patients received scaling and tooth brushing instruction. 1 week after scaling was set as baseline. Probing pocket depth, clinical attachment level, and bleeding on probing were scored at baseline, 4 weeks. Gingival index and plaque index were scored at baseline, 2 weeks, and 4 weeks. The results were as follows: 1. In the experimental group, gingival index, plaque index, probing pocket depth, and clinical attachment level showed statistically significant decrease, but in the control group, significant increase(p<0.05). 2. There was no significant difference between the experimental and the control group in bleeding on probing, but significant decrease in the experimental group and Significant increase in the control group In a time-dependent manner(p <0.05). From these results, it can be concluded that regular use of mouthrinses prepared by sterilized water-generating $device(Purister^{(R)})$ as adjunctives of mechanical plaque control, may be effective to prevent and treat gingivitis and incipient periodontitis.

Identification of Coffee Fragrances Using Needle Trap Device-Gas Chromatograph/Mass Spectrometry (NTD-GC/MS)

  • Eom, In-Yong;Jung, Min-Ji
    • Bulletin of the Korean Chemical Society
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    • v.34 no.6
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    • pp.1703-1707
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    • 2013
  • A fast and simple sampling and sample preparation device, (NTD) has been developed and applied to sample and analyze volatile components from ground coffee beans. Coffee fragrances and other volatile organic compounds (VOCs) were sampled by the NTD and then analyzed by gas chromatograph-mass spectrometry (GC/MS). Divinylbenzene (DVB) particles (80/100 mesh size) were the sorbent bed of the NTD. More than 150 volatile components were first identified based on the database of the mass library and then finally 30 fragrances including caffeine were further confirmed by comparing experimental retention indices (i.e. Kovat index) with literature retention indices. Total sampling time was 10 minutes and no extra solvent extraction and/or reconstitution step need. Straight n-alkanes (C6-C20) were used as retention index probes for the calculation of experimental retention indices. In addition, this report suggests that an empty needle can be an alternative platform for analyzing polymers by pyrolysis-GC/MS.

Development of an Expert System for Optimizing Die and Mold Polishing-I (금형면 자동 다듬질 전문가 시스템 개발에 관한 연구-I -DB 구축을 위한 회전 및 진동 연마 가공의 실험적 연구-)

  • 민헌식;이성환;안유민;조남규;한창수
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.1
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    • pp.38-44
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    • 2002
  • In manufacturing die and mold, polishing: is important as it takes as much as 50% of the production cost. In this research, an attachable type polishing device to a WC machining center was developed. experiments were done with a special1y designed rotation type polishing device. Also an ultra-sonic (vibration type) waving device was introduced to acquire finer surface finishes. From the constructed data base based on the experimental results, it is shown that optimal polishing conditions are generated by the combined use of the rotation type tool and the vibration type tool.

Experimental Study on Coefficient of Flow Convection (유수대류계수에 관한 실험적 연구)

  • 정상은;오태근;양주경;김진근
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.297-302
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    • 2000
  • Pipe cooling method is widely used for reduction of hydration heat and control of cracking in mass concrete structures. However, in order to effectively apply pipe cooling systems to concrete structure, the coefficient of flow convection relating the thermal transfer between inner stream of pipe and concrete must be estimated. In this study, a device measuring the coefficient of flow convection is developed. Since a variation of thermal distribution caused by pipe cooling has a direct effect in internal forced flows, the developed testing device is based on the internal forced flow concept. Influencing factors on the coefficient of flow convection are mainly flow velocity, pipe diameter and thickness, and pipe material. finally a prediction model of the coefficient of flow convection is proposed using experimental results from the developed device. According to the proposed prediction model, the coefficient of flow convection increases with increase in flow velocity and decreases with increase in pipe diameter and thickness. Also, the coefficient of flow convection is largely affected by the type of pipe materials.

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A Experimental Study on the Fire Hazards in Drum-Type Electric Washing Machine (건조일체형 드럼세탁기의 화재위험성에 관한 실험연구)

  • Hong, Sung-Ho
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.3
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    • pp.328-331
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    • 2008
  • This study presents on the analysis fire hazards of drum type electric washing machine. In order to analyze fire hazards fire experiment is conducted. The fire experiment is conducted to simulate under the normal condition and abnormal condition. The experiment under the abnormal condition is simulated in safety device failure, situation of accumulated dust and tracking phenomenon caused by humidity. The results show that fire hazard is high at the abnormal condition. In this paper, we suggest to use the safety device of low operating temperature in electric washing machine for reducing fire hazard.

Real-time Control on LonWorks/IP Virtual Device Network(VDN) for Rail Transit Vehicles (철도차량용 LonWorks/IP 가상 디바이스 네트워크 (VDN)에서의 실시간 분산제어)

  • Choi, Gi-Heung
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.1253-1258
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    • 2004
  • A general idea of implementing and managing real-time control on the VDN for rail transit vehicles is presented. In particular, the virtual device network considered in this paper is composed of Ethernet as the data network and LonWorks network as the device (control) network. A LonWorks/IP web server was used as a gateway to realize peer to peer data communication on the virtual device networks. Experimental results are given to validate the suggested architecture.

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Fluid viscous device modelling by fractional derivatives

  • Gusella, V.;Terenzi, G.
    • Structural Engineering and Mechanics
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    • v.5 no.2
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    • pp.177-191
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    • 1997
  • In the paper, a fractional derivative Kelvin-Voigt model describing the dynamic behavior of a special class of fluid viscous dampers, is presented. First of all, in order to verify their mechanical properties, two devices were tested the former behaving as a pure damper (PD device), whereas the latter as an elastic-damping device (ED device). For both, quasi-static and dynamic tests were carried out under imposed displacement control. Secondarily, in order to describe their cyclical behavior, a model composed by an elastic and a damping element connected in parallel was defined. The elastic force was assumed as a linear function of the displacement whereas the damping one was expressed by a fractional derivative of the displacement. By setting an appropriate numerical algorithm, the model parameters (fractional derivative order, damping coefficient and elastic stiffness) were identified by experimental results. The estimated values allowed to outline the main parameter properties on which depend both the elastic as well as the damping behavior of the considered devices.

Development of New Measurement Device for the Coefficient of Kinetic Friction by Using Side Air-Guide Track (측면 에어 가이드 트랙을 이용한 새로운 운동마찰계수 측정 장치의 개발)

  • Nam, Hyoung Joo
    • Journal of Engineering Education Research
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    • v.21 no.3
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    • pp.12-19
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    • 2018
  • In this study, a new experimental device was developed for measurement of the coefficient of kinetic friction using a photo gate timer system which have advantages of easy and accurate detection of motion. This device, consisting of a side air-guide track and a side friction-free glider, forces a friction sample to move in a straight line without producing unnecessary friction. The new device is compared to two conventional measuring methods of friction for four different friction samples: one is using a camera system and the other is using a force sensor. It is demonstrated that the developed friction device in this study is easier to operate and produces the most accurate and the least deviating results among them. On the basis of these results, we propose that friction experiment using the new friction device is included in general physics experiment, so that engineering students should have a chance to get correct understanding of classical mechanics including friction phenomenon.

Design of Capacitive Displacement Sensor and Gap Measurement with High Precision Using Surface Acoustic Wave Device (표면 탄성파 장치를 응용한 용량 성 변위센서의 설계 및 초정밀 간극 측정)

  • Kim, Jae-Geun;Lee, Taek-Joo;Lim, Soo-Cheol;Park, No-Cheol;Park, Young-Pil;Park, Kyoung-Su
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.5
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    • pp.437-443
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    • 2010
  • SAW device is widely used as band pass filters, chemical or physical sensors, and actuators. In this paper, we propose the capacitive gap measurement system with high precision using SAW device. The research process is mainly composed of theoretical and experimental part. In the theoretical part, equivalent circuit model was used to predict the SAW response by the change of load impedance. In the experimental part, commercialized capacitor was used to see the SAW response by the change of load capacitance to check the feasibility as a sensor unit. After that, experimental setup to measure and adjust the gap was made and the SAW response by the change of gap which caused the capacitance change was measured. Finally, resolution and stroke was decided compared with the signal change and basic measurement noise level.