• Journal of Ocean Engineering and Technology
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• v.20 no.1 s.68
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• pp.16-19
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• 2006

With the fast growth of the shipbuilding industry, the number of lifting lugs used every year has reached onehundred. This paper is aimed at examining the cause of cracking in the hopper top plate, due to block lifting. First of all, we have investigated the fracture surface in the occurrence position of the crack of the hopper top plate, using the scanning electron microscope. In this study, we have evaluated the structural strength for COT super block under present lifting conditions. For this purpose, the equivalent stresses have been calculated by linear elastic analysis, using the finite element program ABAQUS.

• Proceedings of the KWS Conference
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• 1998.10a
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• pp.244-246
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• 1998

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.35-42
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• 2015

Injection molding is a high efficient manufacturing technology for producing plastic parts. On the other hand, the warpage of molded plastic parts is an ubiquitous problem in the injection molding process. The main objective of this study was to minimize the amount of warpage occurring in the injection molding process of a hopper of ATDPS made of crystalline polymer (PP) instead of amorphous polymer (ABS). The moldflow CAE simulation was conducted for the molding process of the hopper to clarify the injection moldability, shear rate, shear stress, warpage by changing the gate shape and the number of ribs installed on the top of the hopper flange. The wide gate shape of runner system and multiple rib installation were found to be useful for minimizing the warpage of the hopper. The validity of the CAE simulations was supported by the injection molding experiment for the optimized design case.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.3
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• pp.212-221
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• 2007

This paper describes on the evaluation and management of work process in suction hopper dredger and grab bucket dredger as an application of a PC-based ECDIS system. The dynamic tracking of dredging bucket and the data logging of grab dredging information were performed by using the grab dredging vessel "Kunwoong G-18". The position and route tracking of the dredger moving toward the ocean dumping site of dredged material was performed by using the hopper dredging vessel "Samyang-7". The evaluation of wok process in the dredging field, for grab dredger, was continuously carried out on January to May, 2006, in Incheon Hang and for hopper dredger, on July to December, 2003, in Busan Hang, Korea. The dredging information, such as dredger's position, heading, dredging depth and route track which was individually time stamped during the dredging operation, was automatically processed in real-time on the ECDIS and displayed simultaneously on the S-57 ENC chart. From these results, we conclude that the ECDIS system can be applied as a tool in order to manage the work process during the dredging operation, and also in order to generate the factual record of the dredging activities that is sufficient for dredging inspector to accurately evaluate the contract performance even in the absence of a full-time onboard inspector.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.9
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• pp.28-34
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• 2022

The flow at the top surface of the hopper is of particular industrial interest. Previously, the velocity distribution inside the hopper was predicted using the simple, void and spot models, which are equations for the particle flow field. However, because these equations cannot predict the velocity distribution at the top surface, a new equation has been recently proposed. This study employed the discrete element method with the changed shape of the particles. Based on the results, the shape of the particle had no effect on the discharge angle and shape of the velocity distribution; however, it greatly affected the size of the velocity distribution and bed thickness of the flowing particles. Therefore, in the future, it is necessary to modify the theoretical equation by considering the shape of the particles.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.27-33
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• 2000

N-Dimethoxyphosphinothionyl carbofuran, PSC, has a high insecticidal activity and low mammalian toxicity. Ten N-phosphinothionyl carbofuran derivatives were synthesized and their insecticidal activities were determined against brown plant hopper (Nilaparvata lugens), green peach aphid (Myzus persicae), diamondback moth (Plutella xylostella), and two-spotted spider mite (Tetranychus urticae). Green peach aphid, diamondback mea and brown plant hopper were controlled over 90% by application of 125 ppm, 125 ppm, and 63 ppm, respectively, of carbosulfan. Two hundred and fifty ppm of newly synthesized compounds could control most of brown plant hopper and diamondback moth. Especially, insecticidal activities of compound 10 against brown plant hopper, diamondback moth, and green peach aphid were similar to those of carbosulfan. Our results show that the newly synthesized derivatives of NV-phosphinothionyl carbofuran have a similar insecticidal activity to carbosulfan.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.263-268
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• 2011

There are many exclusive freight cars in railway freight transportation system. Gondola is one kind of freight cars. Gondolas have a role to carry bulk-type cargo such as coals and ores. A few problems are occurring due to exclusive freight cars. Operation company has redundant freight cars because exclusive freight cars can carry limited items. And purchasing cost of freight cars is higher and higher because of irregular bid. Operation efficiency of gondola is very low because return time of gondola is much longer than that of container car. In this study, we analysed the introduction effect of hopper-type container for through transit. First, we identified the characteristics of spatial distribution on freight stations. And we provided the effect of hopper-type container in terms of operation efficiency, cost reduction, new demand excavation and image enhancement of eco-friendly railroad.

• Journal of the Korean Society of Industry Convergence
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• v.19 no.4
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• pp.193-197
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• 2016

There are many hoppers in the actual industrial plants such as grain hoppers in agricultural companies, surge hoppers in steel companies, and so on. In general, they are time-delay systems so that their level control is not easy. Thus, they have been manually controlled to avoid the overflow and empty out. In this paper, we proposed Fuzzy PID controller for level control of hopper systems. To show the effectiveness of the proposed scheme, some simulation results are given.

• Journal of Animal Environmental Science
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• v.14 no.1
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• pp.53-60
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• 2008

This study was carried out to measure and analyze the vibration levels and modes produced by a hopper type feeder used at laying hen farms, to prevent the vibration resonance and to reduce the vibration of the hopper type feeder (6-tier). The most vibration in a layer house were produced by hopper type feeder as shown the previous study. According to the measurement results, the ratio of transmissibility was as high as 100-638% for natural frequency of 170 Hz or less. And vibration simulations were taken by the results of vibration mode analysis and the weakest points to vibrations were determined accordingly. Then measurement and analysis were taken for those points. The quantities of vibration were 4.6354-4.9118 g($g=9.81^m/s^2$) by axis. In this study, it was found that hopper type feeder generated vibration as much as to influence the ratio of laying eggs of layer. And by the analysis of vibration on the weakest points, design methods and equipment were suggested for isolating/reducing of vibration by each axis.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.163-166
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• 2000

This paper describes the principle of humidity sensor using high frequency resistance method for Hopper-Scale that is used in RPC(Rice processing Complex) which is spreaded out in domestic, and we also understand the principle and specificity of controller and humidity sensor. After artworking the humidity sensor and controller circuit, we measure the humidity of the designed system. In this progress, we suggested substitute parts which are easy to get in domestic and also we could propose correct method of humidity detection.