• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.5
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• pp.107-115
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• 2008

In this research, it has been developed the tongs mechanism by a friction force for curbstone working. This tongs apparatus was farmed to grip and rotate the rectangular curbstone. Specification of this tongs apparatus has been determined by considering a loading weight and reversal load preventing reversal of 1.5 ton excavator. And, specification of the linear actuator has been determined with considering mechanical structure and the operation power demanded by the grip pad friction of tongs apparatus. The safety of the part has been examined from the 3D numerical simulation of the tongs apparatus. The operation system has been arranged to grip and rotate curbstone by on-off switching. The prototype has been established to carry out experiment after installing 1.5 ton excavator.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.185-186
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• 2015

The use of non-bearing lightweight wall has increased recently due to the increase of high-rise buildings and supply of long-life housing. Lightweight wall has advantages such as reducing the self-weight of the building, convenience in installation, and shortening construction period, however, must have a sufficient strength to external force. This study standardized the stiffness (static horizontal load resistance) test method for lightweight walls by using the actual impact load obtained through the load analysis test conducted in the previous studies. The size of specimen was set up as height 2.4m and width 3.0m. Test apparatus and test methods were referred to BS 5234-2:1992. However, the loading level applied to the specimen was divided into 3 steps (3000N, 1000N, 500N) that can be applied selectively depending on the purpose of the wall. The deformation characteristics according to the same loading level were vary depending on the specimen's type, and the evaluation criteria for functional damage may vary depending on the material, method of construction, and purpose of wall. Therefore, we did not suggest unified evaluation criteria of the stiffness to the test results.

• Journal of the Korean Vacuum Society
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• v.12 no.3
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• pp.157-161
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• 2003

Nowadays there are increasing demands for more accurate measurement of atmospheric pressure according to the development of environmental industries. One of the most important pressure gauges for satisfying these demands is a quartz resonance barometer. In order to calibrate such an accurate barometer, laser/ultrasonic mercury manometers have been used. However, complexity and cost of mercury manometers made it out of use gradually. As a substitute, a gas-operated pressure balance is used for calibration of precise barometers. In such a case, commercially available pressure balances cannot be entirely suitable because consequent exposure of the piston, cylinder and masses to the atmosphere causes the problem of contamination. In this paper a device for changing the masses in situ without breaking the vacuum is described. This device made it possible to add or remove weights in the absolute mode, thereby greatly reducing the time between observations. At the same time, we investigated the characteristics of a commercial precise barometer using this new apparatus.

• Tribology and Lubricants
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• v.3 no.1
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• pp.47-51
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• 1987

The purpose of this paper is to study the lubrication characteristics which is occured in contact surface of two meterials. In this study, experimental apparatus which was modelling of the Cold rolling was used. Electric resistance, the temperature variation and the friction coefficient, between Disk and Roller were measured by respectively electric circuit system, temperature probe, and strain gauge. The experiment carried on the disk velocity range of 10m/min to 1000m/min in loading weight 2kg to 18kg.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.1
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• pp.45-54
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• 2020

In this study, an automatic system for improving the working environment and increasing production efficiency of a laver aquaculture industry in Korea was developed by combining a hydraulic control system and a load cell in a current landing work of the laver. The improved gathering laver system allowed the automatic gathering process of the laver in the sea with the hydraulic control system connected to a cutting machine of the laver on the operating ship, which has been used for gathering the laver semi-automatically in a form of the traditional farming method. The transporting process of the laver from an operating ship to the land was improved as follows. A frame installed on the operating ship and the bag nets were designed and made to hold about 1,000 kg of the laver inside. The bag nets contain the laver on the improved operating ship were tied in knots and hooked on a crane using a load cell. The weight is measured immediately by lifting the bag nets through the load cell system. Weight information is communicated to the fishermen and successful bidders through the application. The advantages of the improved system can help fishermen to fish by improving their working environment and increasing production efficiency. The field survey to improve the landing operation of the laver aquaculture was conducted in Gangjin, Goheung, Shinan, Wando, Jindo, and Haenam in South Jeonnam Province. A total of 10 sites including Gunsan in Jeonbuk Province, Daebu Island in Ansan City, Jebu Island in Hwaseong City in Gyeonggi Province, and Seocheon in Chungnam Province were searched to collect data. Prototypes of the system were tested at the auction house of laver located in Goheung, where laver collection using hydraulic control and landing using road cell could be improved.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.3
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• pp.313-327
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• 1999

The aim of this study was to compare wear resistance of resin denture teeth opposing various restorative materials. The wear resistance of conventional acrylic resin teeth(Trubyte Biotone) and three high-strength resin teeth(Bioform IPN, Endura, SR-Orthosit-PE) opposing different restorative materials(gold alloys, dental porcelain, composite resin) was compared. Wear tests were conducted with a sliding-induced wear testing apparatus which applied 100,000 strokes to the specimen in a mesio-distal direction under conditions of 100 stroke/min and constant loading of 1Kgf/tooth. Wear resistance of the resin denture teeth was evaluated by the following criteria : 1) wear depth, 2) weight loss, and 3) SEM observation. Results were as follows. 1. When opposed to gold alloys and composite resin, high-strength resin teeth showed superior wear resistance compared to acrylic resin teeth. But, in cases opposing dental porcelain, differences between the wear of the high-strength and acrylic resin teeth were not statistically significant (p<0.05). 2. When comparing wear resistance among high-strength resin teeth, opposing gold alloys, Endura was slightly more resistant and while in cases opposing dental porcelain, SR-Orthosit-PE was showed to be slightly resistant(p<0.05). 3. The wear of high-strength resin teeth was greater by 5 to 7 times when opposing porcelain and 2 to 3 times when opposing composite resin compared to gold alloys(p<0.05). 4. SEM observations of the wear surface showed that wear of resin teeth opposing gold alloys is a fatigue type of wear and wear of resin teeth opposing dental porcelain is fatigue and abrasion type of wear. Trubyte Biotone showed more severe fatigue type of wear than high-strength resin teeth. In conclusion, the use of dental porcelain should seriously be considered as restorative material in cases opposing resin denture teeth and improvement seems to be needed on resin teeth in the areas of wear resistance.

• Journal of the Korean Geotechnical Society
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• v.25 no.4
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• pp.31-38
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• 2009

A continuous, fast, and convenient experimental method, replacing recent tests such as standard oedometer or self weight consolidation test, is needed for the determination of the consolidation behavior of unformed soft soils. This study introduced the seepage induced fast consolidation test using the flow pump technique. It can obtain the consolidation characteristics of unformed soft soils conveniently and fast. The seepage induced consolidation test apparatus consists of a modified triaxial cell, differential pressure transducer, flow pump, and displacement transducer. The test continuously proceeds with starting seepage forces induced consolidation, loading consolidation, and permeability test on the same sample. In addition, this test result was compared with the standard oedometer test result to make this method valid. From this study it was found that this method is a convenient and time saving effective method for obtaining data required for calculation of consolidation settlement of unformed soft soils.