• Title/Summary/Keyword: experimentals

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Evaluation of Underwater Dam Concrete Structure Repair by Patching Material (댐 시설물 수중구조체 보수용 패칭재료의 적용 가능성 평가)

  • Kim, Wan-Young
    • Journal of The Korean Society of Agricultural Engineers
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    • v.51 no.6
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    • pp.77-81
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    • 2009
  • This study was performed to evaluate applicability of patching materials for underwater dam concrete structure. Two kinds of patching materials was investigated. Laboratory experimentals were conducted by workability, compressive strength, bond strength, chloride ion penetration, abrasion resistance. Test results showed that the most performances are relatively good except chloride ion penetration.

A fuzzy SOC based pressure tracking controller design for hydroforming process (Fuzzy SOC를 이용한 하이드로 포밍 고정의 압력제어기 설계)

  • 김문종;박희재;조형석
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.350-355
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    • 1990
  • A pressure tracking of hydroforming process is considered in this paper. To account for nonlinearities and uncertainty of the process. A fuzzy SOC based iterative learning control algorithm is proposed. A series of experimentals were performed for the pressure tracking control of the process. The experimental results show that regardless of inherent nonlinearties and uncertainties associated with hydraulic system. A good pressure tracking control performance is obtained using the proposed fuzzy learning control algorithm.

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Simulation and Experimentals of a Bi-Directional Converter with Input PFC on SRM System

  • Maged Maged N.F.
    • Journal of Power Electronics
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    • v.6 no.2
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    • pp.121-130
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    • 2006
  • This paper presents the performance and efficiency of a drive system incorporating a switched-reluctance motor (SRM) with input power factor correction (PFC). The proposed system consists of a PFC, bi-directional converter, an inverter, and a SRM operating as based voltage source drives (VSD). First, theoretical analysis is made for each identified mode of operation in the drive system. This is followed by comparing the performance of the SRM drive system with and without a PFC circuit. The losses are also calculated for both systems and overall efficiency. Experimental results are presented to prove the theoretical analysis.

A Study on the Abnormal Behavior of the Viscosity near the Critical Point

  • Kim, Won-Soo;Pak, Hyung-Suk;Chair, Tong-Seek
    • Bulletin of the Korean Chemical Society
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    • v.10 no.4
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    • pp.372-374
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    • 1989
  • The new viscosity theory is applied to the abnormal behavior of the viscosity near the critical point. This theory suggests that the viscosity is equal to the product of the absolute pressure(kinetic pressure + internal pressure) and the collision time. We can find this abnormal behavior to be due to the large collision time near the critical point. The agreements between theoriticals and experimentals of the critical enhancement are satisfactory.

Relationship between Forward Head Posture and Craniomandibular Disorders (두개하악장애와 두부전방자세와의 관계)

  • Kyung-Soo Han
    • Journal of Oral Medicine and Pain
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    • v.19 no.1
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    • pp.137-149
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    • 1994
  • This study was performed to investigate the relationship between Forward Head Posture(FHP) and Craniomandlbular Disorders(CMDs). Many studies reported that there was some relationship between them, however, there is still controversy. So It Is necessary to observe and compare many more patients with CMDs wirh normal controls. For the study 85 patients with CMDs and 37 dental students were selected as experimentals and controls, respectively. And the experimentals were classified Into two groups, that is, TMJ internal derangement group and muscle disorders group according to clinical diagnosis. For measuring the FHP, CROM(Cervical-Range-of-Notion)was used. This goniometer is composed of three part. First, gravity goniometer for flexion and extension. Second, magnetic compass and yoke for rotational movement. And last, forward head arm and vertebra locator for forward head posture. Next T-Scan, electronic occlusal analyzer, was used for recording of occlusal contact state. Other items such as maximum opening, lateral excursion, Helkimo's anamnestic index, and muscle palpation point from Friction's craniomandibular index were checked clinically by one examiner. The result of this study were as follows : 1. In male, control group showed much more measurement in resting forward head posture than did experimental group. But there were not significant differences between groups in female subject. From this results, the author contended that CROM is new measuring system and differ from other goniometers in some aspect, so that results should be re-evaluated 2. Mean value of maximum mouth opening in nearly all groups were greater than 40mm. and mouth opening had a significant correlation with occlusal force and with anamnestic index both sex. 3. Mean value of palpation point had not any correlationship with forward head posture in both sex, but there was significant difference between upper and lower group by rounded shouldes. 4. In summary, there was no significant relationship between forward head posture and sign and symptom of Craniomandibular Disorders.

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Prediction of Laminate Composite Strength Using Probabilistic Approach (확률분포를 이용한 복합재료의 강도예측)

  • 조영준;강태진;이경우
    • Composites Research
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    • v.13 no.1
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    • pp.33-39
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    • 2000
  • A numerical approach for predicting the ultimate strength of laminate composites has been studied using the Weibull distribution of the strengths of lamina plies. The probabilistic initial failure strengths of laminates were calculated using Tsai-Hill failure criterion. The ultimate strength of the laminate composites has been predicted using progressive failure analysis. The experimental results show that the strength prediction based on the Weibull distribution of ply strength reasonably agrees well with the experimentals better than equal strength assumption.

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Experimental Investigations on Barrier Oxidation in $N_{B}/A_{L}O_{X}/N_{B}$ Josephson Junctions

  • Kim, Kyu-Tae;Hong, Hyun-Kwon;Lee, Sang-Hwa;Nam, Du-Woo;Lee, Kyu-Won
    • Progress in Superconductivity and Cryogenics
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    • v.5 no.1
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    • pp.17-20
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    • 2003
  • Josephson junctions were fabricated for several oxidation conditions and several junction sizes. Considering self-field effect suppressing the observed critical current (Ic) at large junctions, the observed Ic values were in good agreement with theoretical prediction. The predicted junction critical current for small junction limit was also confirmed by experiment. The dependence of the estimated Jc as a function of oxidation exposure showed that our junctions have lower Jc than other authors' at the same oxidation exposure. This is thought to be one of equipment-specific phenomena. Details of experimentals will be reported with brief discussion.

A Study on the Removal of SOx/NOx by a Pulsed Corona Discharge in the Wire-Plate Reactor (Wire-Plate 반응기에서 펄스 코로나 방전을 이용한 탈황 탈질에 관한 연구)

  • Shin, Wan-Ho;Song, Yong-Hoon;Kim, Han-Seok;Choi, Yeon-Seok;Kim, Seok-Joon
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1910-1912
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    • 1996
  • This paper presents the results of laboratory experimentals to remove $SO_2$ and $NO_x$ by a pulsed corona discharge in the wire-plate reactor. A rotating spark gap switch was used to generate the pulse by chewing the dc high voltage. Repetition frequency of the pulse was 60Hz and rising time of 50ns. The photo pictures of positive streamer corona taken by ICCD camera, pulse voltage and current were measured using a digital oscilloscope. Simultaneous effects of $C_{2}H_{4}$ injection and heterogeneous chemical reactions on nonthermal plasma process to remove $SO_2$ and $NO_x$ from flue gas were investigated in the present study

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Stress Relaxation of Poly(methyl acrylate)-Poly(acrylonitrile) Copolymers (Poly(methyl acrylate)-Poly(acrylonitrile) 공중합체의 응력완화)

  • Kim, Nam-Jeong
    • Elastomers and Composites
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    • v.47 no.3
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    • pp.223-230
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    • 2012
  • The rheological parameters of poly(methyl acrylate)-poly(acrylonitrile) copolymers were obtained by applying the experimental stress relaxation curves to the theoretical equation of the Eyring-Halsey non-Newtonian model. The experimentals of stress relaxation were carried out using the tensile tester with the solvent chamber. The determination of rheological parameters was performed from computer calculation. It was observed that the rheological parameters of these copolymer samples are directly related to the self diffusions and viscosities and activation energies of flow segments.