• Title/Summary/Keyword: PAD Response

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Performance of Rotational Friction Dampers Under earthquake excitation (회전형 Friction Damper의 거동 특성 연구)

  • 배춘희;박영필
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.810-813
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    • 2004
  • A study on the dynamic response of single-storey steel frames equipped with a rotational friction damper is presented. Extensive testing was carried out for assessing the friction pad material, damper unit performance and foaled model frame response to lateral harmonics excitation. Numerical simulations based on non-linear time history analysis were used to evaluate the seismic behaviour of steel frames with rotational frictional damper. It Is demonstrated that using discrete friction dampers of proper parameters to link steel frame can reduce dynamic response significantly.

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A Study on the Development of Overload Detecting Pad for Low Speed WIM System (저속 WIM 시스템용 과적검지 패드 개발에 관한 연구)

  • Lee, Choon-Man;Choi, Young-Ho;Kim, Eun-Jung
    • Journal of the Korean Society for Precision Engineering
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    • v.34 no.3
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    • pp.179-184
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    • 2017
  • Recently, traffic accidents and damage on the highway have increased because of overloaded vehicles. The existing overload-detecting system has a low accuracy rate. An overload-detecting system using a weigh-in-motion (WIM) system has been developed to solve this problem. The WIM system can be used to detect overloaded vehicles by measuring the weight of the vehicles. The WIM system is divided into high-speed and low-speed types. The inaccuracy rate in the low-speed WIM system results mainly from the low response rate of the sensor when the velocity is moving at more than 20 km/h. In this study, a low-speed overload-detecting pad with a hydraulic structure using a WIM system was developed to make the system more accurate. The structural and formal analysis was carried out by using a finite element method (FEM) in order to analyze the structural stability and the extrusion velocity of the system. In addition, a static load test was performed to confirm the linearity and accuracy of the pad.

Journal Bearing Design Retrofit for Process Large Motor-Generator - Part I : Bearing Performance Analysis (프로세스 대형 모터-발전기의 저어널 베어링 설계 개선 - Part I : 베어링 성능해석)

  • Lee, An Sung
    • Tribology and Lubricants
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    • v.28 no.5
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    • pp.197-202
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    • 2012
  • In this study, with the purpose of fundamentally improving the unbalance response vibration of a large PRT motor-generator rotor by design, a performance improvement design analysis is carried-out by retrofitting tilting pad bearings, replacing the plain partial journal bearings that were originally applied for operation at a rated speed of 1,800 rpm. In this process, a goal of the design analysis is to obtain a design solution for maximizing the direct stiffness of the bearings while satisfying the key basic lubrication performance requirements such as the minimum lift-off speed and maximum oil-film temperature. The results show that with a careful design application of tilting pad journal bearings for operation at such a relatively low speed of 1,800 rpm, direct stiffness increment of the bearings by about two times can be effectively achieved. Prevention of pad unloading is also considered in the analysis. Moreover, the designs of elliptical and offset half journal bearings are also analyzed and reviewed.

Consumer's Affective Response Formation from Experience of Travel Agency (여행사경험에 의해 형성되는 소비자의 감성적 반응)

  • Jung, Moon Young;Kim, Gye Seok
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.7 no.4
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    • pp.33-40
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    • 2012
  • The major purpose of this study is to examine the moderating role of affect intensity, an important individual difference variable, upon affect formation based upon PAD framework from the experience of some dimensions of tavel aency or company. Research findings from the analysis of empirical data are as follow. First of all, four factors of customer's experience of travel agency(Resposiveness; Courtesy; Competency; Differentiation) are related to three affect represented by PAD framework(Pleasure; Arousal; Dominance). Moreover factors of experiences have differential influence upon formation of affective responses. Secondly, customers' Affect Intensity has moderating effects upon the formation of affects by the experience from dimensions of travel agency. The third finding is that the affect induced by travel agency has differential influence upon the formation of attitude toward travel agency and the formation of intention of repurchase of the travel service from that agency.

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Mechanism of Jaeumgenby-tang adding Aurantii FructusㆍGastrodae Rhizoma on the Improvement against Changes of Cerebral Hemodynamics in Cerebral Ischemia Rats (자음건비탕 가지각ㆍ천마가 뇌허혈동물의 뇌혈유력학 변동 개선에 미치는 작용기전)

  • Woo Jeong Hyun
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.17 no.5
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    • pp.1194-1201
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    • 2003
  • Jaeumgenby-tang(JGT) have been used in oriental medicine for many centries as a therapeutic agent of vertigo caused by deficiency of qi(氣) and blood(血). Effect of Aurantii Fructus(AF) take off the phlegm by promoting the circulation of qi, Gastrodae Rhizoma(GR) has effects treating for headarch, vertigo by calming the liver and suppressing hyperactivity of the liver-yang (陽). I investigated whether injection of JGT adding AFㆍGR extract(JTG) affects cerebral hemodynamics [regional cerebral blood f1ow(rCBF), pial arterial diameter(PAD) in cerebral ischemia rats by MCA occlusion method, and I designed to make manifest whether JTG is mediated by adrenergic β-receptor, cyclooxygenase or guanylate cyclase. The changes of rCBF was determinated by laser-doppler flowmetry(LDF), and the changes of PAD was determinated by video microscope and width analyzer. The results were as follows in cerebral ischemic rats; The changes of rCBF and PAD were increased stabilizly by treatment with JTG(10 ㎎/kg, i.v.) during the period of cerebral reperfusion, and pretreatment with propranolol and indomethacin were increased JTG induced increase of rCBF and PAD during the period of cerebral reperfusion. Pretreatment methylene blue was decreased JTG induced increase of rCBF and PAD during the period of cerebral reperfusion. In conclusion, JTG causes a diverse response of rCBF and PAD, and action of JTG is mediated by adrenergic β-receptor and cyclooxygenase. I suggest that JTG has an anti-ischemic effect through the improvement of crebral hemodynamics.

Estrogen Attenuates the Pressor Response Mediated by the Group III Mechanoreflex (폐경전후 여성의 Group III 기계적 수용기 자극 시 운동승압반사의 비교)

  • Park, Seung-Ae;Kim, Jong-Kyung
    • Journal of Korean Academy of Nursing
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    • v.41 no.2
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    • pp.191-196
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    • 2011
  • Purpose: We investigated the effects of group III mechanoreceptors to cardiovascular responses in both pre-menopausal woman and post-menopausal woman during passive ankle dorsiflexion (PAD). Methods: Twenty healthy volunteers (10 post-menopausal women and 10 pre-menopausal women) were recruited for this study. Stroke volume (SV), heart rate (HR), cardiac output (CO), and total vascular conductances (TVC) were measured continuously throughout the experiment. To stimulate the group III mechanoreceptors, PAD was performed for one minute. Results: The results showed that mean arterial pressure (MAP) mediated by the mechanoreflex activation was significantly increased in both groups. However, this pressor response was significantly higher in post-menopausal women. This reflex significantly increased both SV and CO in pre-menopausal women, while there were no differences in post-menopausal women. There was no difference in HR in either group. The mechanoreflex significantly decreased TVC in post-menopausal woman, while there was no difference in pre-menopausal woman. Conclusion: The results indicate that the excessive pressor response mediated by the mechanoreflex occurs due to overactivity of group III mechanorecptors and the mechanism is produced mainly via peripheral vasoconstriction in post-menopausal women.

Seismic Capacity Evaluation of Existing Medium-and low-rise R/C Frame Retrofitted by H-section Steel Frame with Elastic Pad Based on Pseudo-dynamic testing (유사동적실험에 의한 탄성패드 접합 H형 철골프레임공법으로 보강 된 기존 중·저층 R/C 골조의 내진성능 평가)

  • Kim, Jin-Seon;Lee, Kang-Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.4
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    • pp.83-91
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    • 2021
  • In this study, to improve the connection performance between the existing reinforced concrete (R/C) frame and the strengthening member, we proposed a new H-section steel frame with elastic pad (HSFEP) system for seismic rehabilitation of existing medium-to-low-rise reinforced concrete (R/C) buildings. This HSFEP strengthening system exhibits an excellent connection performance because an elastic pad is installed between the existing structure and reinforcing frame. The method shows a strength design approach implemented via retrofitting, to easily increase the ultimate lateral load capacity of R/C buildings lacking seismic data, which exhibit shear failure mechanism. Two full-size two-story R/C frame specimens were designed based on an existing R/C building in Korea lacking seismic data, and then strengthened using the HSFEP system; thus, one control specimen and one specimen strengthened with the HSFEP system were used. Pseudodynamic tests were conducted to verify the effects of seismic retrofitting, and the earthquake response behavior with use of the proposed method, in terms of the maximum response strength, response displacement, and degree of earthquake damage compared with the control R/C frame. Test results revealed that the proposed HSFEP strengthening method, internally applied to the R/C frame, effectively increased the lateral ultimate strength, resulting in reduced response displacement of R/C structures under large scale earthquake conditions.

Effect of nonlinearity of fastening system on railway slab track dynamic response

  • Sadeghi, Javad;Seyedkazemi, Mohammad;Khajehdezfuly, Amin
    • Structural Engineering and Mechanics
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    • v.83 no.6
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    • pp.709-727
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    • 2022
  • Fastening systems have a significant role in the response of railway slab track systems. Although experimental tests indicate nonlinear behavior of fastening systems, they have been simulated as a linear spring-dashpot element in the available literature. In this paper, the influence of the nonlinear behavior of fastening systems on the slab track response was investigated. In this regard, a nonlinear model of vehicle/slab track interaction, including two commonly used fastening systems (i.e., RFFS and RWFS), was developed. The time history of excitation frequency of the fastening system was derived using the short time Fourier transform. The model was validated, using the results of a comprehensive field test carried out in this study. The frequency response of the track was studied to evaluate the effect of excitation frequency on the railway track response. The results obtained from the model were compared with those of the conventional linear model of vehicle/slab track interaction. The effects of vehicle speed, axle load, pad stiffness, fastening preload on the difference between the outputs obtained from the linear and nonlinear models were investigated through a parametric study. It was shown that the difference between the results obtained from linear and nonlinear models is up to 38 and 18 percent for RWFS and RFFS, respectively. Based on the outcomes obtained, a nonlinear to linear correction factor as a function of vehicle speed, vehicle axle load, pad stiffness and preload was derived. It was shown that consideration of the correction factor compensates the errors caused by the assumption of linear behavior for the fastening systems in the currently used vehicle track interaction models.

Studies on the Effect of Captafol and Ethanol the Murine Immune System (Captafol 免疫毒性에 미치는 Ethanol의 영향)

  • 박귀례
    • Journal of Environmental Health Sciences
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    • v.14 no.1
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    • pp.115-122
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    • 1988
  • Captafol (1H-Isoindole-1.3(2H)-dione, 3a, 4, 7, 7a-tetrahydro-2-[1, 1, 2, 2-tetrahydroethyltkio]) is widely used as fungicide in agriculture. Immune modulatory effects of captafol and ethanol were studied in mice. Mice administered captafol intra peritoneally every other day for 5 times, and ethanol per os as captafol. Mice were sensitized and challenged with sheep red blood cells, serum antibody titer, foot pad swelling, and rosette forming cell number were mediated immune response. 1. The result show that humoral immune response and cell mediatea response were suppressed by captafol. 2. Especially effect of ethanol on the captafol immune response were significantly suppressed the humoral immune response and cell mediated immune response.

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A Study on the Causes of Security Vulnerability in 'Wall Pads' ('월패드'의 보안 취약 원인에 관한 고찰)

  • Kim Sang Choon;Jeon Jeong Hoon
    • Convergence Security Journal
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    • v.22 no.2
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    • pp.59-66
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    • 2022
  • Recently, smart home technology has been developed with a great response due to the convenience of home automation. Smart home technology provides various services by connecting various Internet of Things (IoT) and sensors to a home network through wired/wireless networks. In addition, the smart home service easily and conveniently controls lighting, energy, environment, and door cameras through a wall pad. However, while it has become a social issue due to the recent hacking accident of wall pads, personal information leakage and privacy infringement are expected. Accordingly, it is necessary to prepare preventive and countermeasures against security vulnerability factors of wall pads. Therefore, this study expects that it can be used as basic data for future smart home application and response technology development by examining the weak causes and countermeasures related to wall pads.