• Title/Summary/Keyword: control forces

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Development of a Gripper and a Cutter for the Automatic Harvest of Green Perilla Leaves (식용 들깻잎 수확 자동화 시스템의 그리퍼 및 절단 컷터 개발)

  • 송영호;장동일;방승훈;조한성
    • Journal of Biosystems Engineering
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    • v.28 no.6
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    • pp.497-504
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    • 2003
  • The objectives of this study were to develop a harvesting gripper for perilla leaves and test its performance, which was a partial work of the automated perilla leaves harvesting system development. The results of this study could be summarized as the followings: The shear forces for harvesting the perilla were measured. The measured results showed that the average shear force required was 12.13N for cutting the petioles attached to the perilla stalks, and the maximum of 17.42N. The inner diameter of air cylinder used was 6mm and the air pressure was maintained as 0.7㎫ during the tests. The time required for cutting perilla leaves could be adjusted by the control program and cutting operation could be done within 1- 10 seconds. The performance tests were conducted to harvest the perilla leaves by the gripper developed. The average success rates of cutting were 72.2% for the first test, 78.5% for the second, and 74.2% for the last. The perilla leaves were not damaged by the gripper The whole system operation could be finished within three seconds except the delay time for dropping harvested leaves.

Balance Recovery Mechanisms Against Anterior Perturbation during Standing (직립자세에서의 전방향 동요 시 균형회복 기전)

  • 태기식;김영호
    • Journal of Biomedical Engineering Research
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    • v.24 no.5
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    • pp.435-442
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    • 2003
  • In this paper, biomechanical aspects of dynamic대학교postural responses against forward perturbations were experimentally determined simultaneous measurements of joint angles, accelerations. EMG activations, center of pressure(CoP) movements and ground reaction forces(GRF), Thirteen young healthy volunteers, stood on a flat platform, were translated into the forward direction by an AC servo-motor at two separate velocities(0.1m and 0.2m/s). In order to recover postural balance against the forward perturbation, joint motions were observed in the sequence of the ankle dorsiflexion, the knee flexion and then the hip flexion during the later acceleration phase. Both acceleration patterns at the heel and the sacrum were shown the forward acceleration pattern during the later acceleration phase and early of constant velocity phase as increasing platform velocity, respectively. Tibialis anterior(TA) for the ankle dorsiflexion and biceps femoris(BF) for the knee flexion. the primary muscle to recover the forward perturbation, was activated during the half of acceleration phase. Ankle strategy was used for slow-velocity perturbation, but mixed strategy of both ankle and hip used for the fast-velocity perturbation. In addition, parameters of perturbation such as timing and magnitude influenced the postural response against the perturbation.

The Effect of Blanching and Lactic Acid Bacterial Inoculation on the Quality of Kimchi (열처리 및 젖산균 접종이 김치의 품질에 미치는 영향)

  • Park, Hee-Ok;Kim, Yoo-Kyeong;Yoon, Sun
    • Korean journal of food and cookery science
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    • v.9 no.2
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    • pp.61-66
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    • 1993
  • The object of this study was to investigate the effects of blanching and lactic acid bacterial inoculation on the quality of kimchi. The pHs of the group added Leuconostoc mesenteroides were rapidly decreased, and then kept almost steady states. However, the pHs of the groups added Bifidobacterium bifidum were gradually decreased. Blanching treatment reduced the number of viable cells. At the beginning of the fermentation, the total organic acid contents of the blanched groups were lower than those of the non-blanched groups, but later on they were higher. With fermentation, the contents of malic, citric and fumaric acid were decreased in the control group, but increased in the cultured groups and all blanched groups. The cutting forces of the blanched groups were higher than those of the non-blanched groups during the whole fermentation period. The inoculation of Leu. mesenteroides was effective on the preservation of ascorbic acid. Blanching and the inoculation of Leu. mesenteroides gave good effect on the sensory acceptability. The acceptability of the groups added Bifidobacterium bifidum was low in initial fermentation period, but increased during the late fermentation period.

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The controllable fluid dash pot damper performance

  • Samali, Bijan;Widjaja, Joko;Reizes, John
    • Smart Structures and Systems
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    • v.2 no.3
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    • pp.209-224
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    • 2006
  • The use of smart dampers to optimally control the response of structures is on the increase. To maximize the potential use of such damper systems, their accurate modeling and assessment of their performance is of vital interest. In this study, the performance of a controllable fluid dashpot damper, in terms of damper forces, damper dynamic range and damping force hysteretic loops, respectively, is studied mathematically. The study employs a damper Bingham-Maxwell (BingMax) model whose mathematical formulation is developed using a Fourier series technique. The technique treats this one-dimensional Navier-Stokes's momentum equation as a linear superposition of initial-boundary value problems (IBVPs): boundary conditions, viscous term, constant Direct Current (DC) induced fluid plug and fluid inertial term. To hold the formulation applicable, the DC current level to the damper is supplied as discrete constants. The formulation and subsequent simulation are validated with experimental results of a commercially available magneto rheological (MR) dashpot damper (Lord model No's RD-1005-3) subjected to a sinusoidal stroke motion using a 'SCHENK' material testing machine in the Materials Laboratory at the University of Technology, Sydney.

Study of wind tunnel test results of high-rise buildings compared to different design codes

  • Badri, Abdulmonem A.;Hussein, Manar M.;Attia, Walid A.
    • Wind and Structures
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    • v.20 no.5
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    • pp.623-642
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    • 2015
  • Several international codes have been developed for evaluating wind loads on structures; however, the wind structure interaction could not be accurately captured by these codes due to the gusty nature of wind and the dynamic behavior of structures. Therefore, the alternative wind tunnel testing was introduced. In this study, an introduction to the available approaches for wind load calculations for tall buildings was presented. Then, a comparative study between different codes: the Egyptian code, ECP 201-08, ASCE 7-05, BS 6399-2, and wind tunnel test results was conducted. An investigation has been carried out on two case studies tall buildings located within the Arabian Gulf region. Numerical models using (ETABS) software were produced to obtain the relation between codes analytical values and wind tunnel experimental test results for wind loads in the along and across wind directions. Results for the main structural responses including stories forces, shears, overturning moments, lateral displacements, and drifts were presented graphically in order to give clear comparison between the studied methods. The conclusions and recommendations for future works obtained from this research are finally presented to help improving Egyptian code provisions and show limitations for different cases.

Study on Oriental Prescription for Medicinal Food Applications -Effects and Mechanism of Saengmaegsan on the Relaxation of Contracted Artery and Regional Cerebral Blood Flow- (한약처방을 활용한 Medicinal Food의 개발에 관한 연구 - 생맥산이 수축동맥의 이완과 국소뇌혈류량에 미치는 효과 및 기전 -)

  • Park Sung-Hye;Kim Woon-Ju
    • Journal of the East Asian Society of Dietary Life
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    • v.15 no.5
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    • pp.606-612
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    • 2005
  • This study was performed to provide basic data that predict the application of Saengmaegsan(SMS) as medicinal food. SMS has been used in oriental medicine for many years as a therapeutic agent for cerebral disease. We examined the effects of SMS on physiological function in isolated abdominal aorta and femoral artery from rabbit and measured the changes of regional cerebral hood flow(rCBF), which was continually monitored by laser-doppler flowmeter and pressure transducer in anesthetized adult Spargue-Dawley rats through the data acquisition system composed of MacLab and Macintosh computer. The contraction forces by injection of norephinephrine in isolated abdominal aorta and femoral artery were significantly decreased in each concentration of SMS treatment compared with control. rCBF was increased by SMS in a dose-dependent manner. These results suggest that SMS causes a diverse response of rCBF and arterial diameter. These mechanism in rCBF increase may be mediated by prostaglandis, cyclic GMP and adrenergic $\beta-receptor$. Also mechanism in artery contraction decrease is also mediated by prostaglandis and cyclic GMP. These results indicate that SMS can be nsed as a safe and clinically applicable as a supplementation of diet therapy for cerebral cardiovascular disease patients.

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Development of High Precision Plate Holder in Automotive Seat Recliner by Mechanical Press(I) : Application of FCF Method (기계식 프레스에 의한 자동차 시트 리클라이너의 고정밀 플레이트 홀더 개발(I) : FCF 공법 적용)

  • Kim, Byung-Min;Choi, Hong-Seok;Chang, Myung-Jin;Bae, Jae-Ho;Lee, Seon-Bong;Ko, Dae-Cheol
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.7
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    • pp.55-63
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    • 2008
  • Fine blanking is a process of press shearing which makes it possible to produce the thick sheet metal of the finished surface and the close dimensional accuracy over the whole material thickness in the single blanking operation. In this paper, a plate holder of automotive seat recliner is manufactured by FCF(Flow Control Forming) method using the conventional mechanical press instead of the fine blanking press. Main processes for manufacturing of the plate holder by FCF method are embossing, half blanking and trimming processes. Optimal clearance, stripper force and counter force to increase the dimensional accuracy of the plate holder have been investigated by FE-analysis. As a result of FE-analysis, the clearance for both embossing and half blanking processes was -2%t and the forces of stripper and counter were 25ton and 15ton, respectively. After manufacturing the plate holder by FCF method, the measured dimensional characteristics have been compared with the required specifications as the final product. Although the dimensional accuracy of the plate holder manufactured by FCF method was a little inferior to that by fine blanking process, it was satisfactory in a general sense.

Effects of Partial Beef Fat Replacement with Gelled Emulsion on Functional and Quality Properties of Model System Meat Emulsions

  • Serdaroglu, Meltem;Nacak, Berker;Karabiyikoglu, Merve;Keser, Gokcen
    • Food Science of Animal Resources
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    • v.36 no.6
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    • pp.744-751
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    • 2016
  • The objective of this study was to investigate the effects of partial beef fat replacement (0, 30, 50, 100%) with gelled emulsion (GE) prepared with olive oil on functional and quality properties of model system meat emulsion (MSME). GE consisted of inulin and gelatin as gelling agent and characteristics of gelled and model system meat emulsions were investigated. GE showed good initial stability against centrifugation forces and thermal stability at different temperatures. GE addition decreased the pH with respect to increase in GE concentration. Addition of GE increased lightness and yellowness but reduced redness compared to control samples. The results of the study showed that partial replacement of beef fat with GE could be used for improving cooking yield without negative effects on water holding capacity and emulsion stability compared to C samples when replacement level is up to 50%. The presence of GE significantly affected textural behaviors of samples (p<0.05). In conclusion, our study showed that GE have promising impacts on developing healthier meat product formulations besides improving technological characteristics.

The Critical Speed Analysis of the Differential Planetary Gear Train of a Concrete Mixer Truck Mixer Reducer (콘크리트 믹서 트럭용 믹서 감속기의 차동 유성 기어 트레인에 대한 위험속도 해석)

  • Bae, Myung Ho;Bae, Tae Yeol;Kim, Dang Ju
    • Journal of Drive and Control
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    • v.14 no.1
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    • pp.1-7
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    • 2017
  • The power train of a concrete truck mixer reducer includes differential planetary gears to get a large reduction ratio for operating the mixer drum in a compact structure. These differential planetary gears are a very important part of the mixer reducer where strength problems are the main concern. Gear bending stress, gear compressive stress and scoring failure are the main concerns. Many failures in differential planetary gears are due to the insufficient gear strength and resonance problems caused by major excitation forces such as gear mating failure in the transmission. In the present study, where the excitation frequencies are the gear tooth passing frequencies of the mating gears, a Campbell diagram is used to calculate differential planetary gear critical speeds. Mode shapes and natural frequencies of the differential planetary gears are calculated by CATIA V5. These are used to predict gear resonance failures by comparing the working speed range with the critical speeds due to the gear transmission errors of the differential planetary gears.

The study of wheel unloading change in case of tilting actuation (틸팅차량의 곡선부 틸팅동작 시 윤중감소율 병화에 대한 고찰)

  • Kim Nam-Po;Kim Jung-Seok;Oh Il-Geun
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.435-442
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    • 2004
  • Tilting train allow the train to pass curve at higher speed without affecting passenger comfort. As the tilting trains run curve track about 30$\%$ higher than non-tilting trains, the centrifugal force and dynamic force will be higher. Therefore it is very important for tilting train to ensure safety against derailment, and to reduce the lateral track forces by applying light-weight design, optimized suspension design and steering mechanism. The 180 km/h Korean Tilting Train(TTX) which is now developing as a part of the Korean National R & D project, was designed and analytically verified to meet these special requirements. This paper describes the analytic study to verify the safety against derailment, especially on the wheel unloading in case of tilting actuation. The severest curve geometry and curving speed was assumed, the tilting control pattern was also assumed as trapezoidal force function applied to tilting bolster and bogie frame. For the comparison, the operation with the speed of tilting train without tilting actuation was numerically simulated and the operation with the balanced speed without tilting actuation was also numerically simulated. Through the numerical simulation of various operating case, we found that derailment quotients, wheel unloading and Q/P was not affected by tilting actuation and that the bogie of TTX was nicely designed to satisfy the safety against the derailment.

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