• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.222-225
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• 2006

Pull-off test is widely used to evaluate bond performance between concrete and FRP composite. However, reliability of experiment result declines due to many difference between test methods of each national standards. This study analyzed problems of various existing test methods for pull-off test and suggested standardized test method. In addition, since tensile strength of concrete is smaller than bond strength of epoxy resin, maximum bond strength of epoxy resin shall be limited within tensile strength of concrete. Alternative testing method, therefore, which decrease FRP adhesion areas than concrete adhesion areas is suggested to widen test range of bond strength in pull-off test. In the experimental results, bond performance can be estimated up to two times of tensile strength of concrete by reducing FRP adhesion areas by 1/3.

• Journal of Korean Clinical Health Science
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• v.4 no.3
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• pp.622-633
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• 2016

Purpose. The purpose of this study was compared of left dominant and the right dominant hands about coordination. Methods. The participants were 30 occupational therapy students in M university in Changwon, from April 28th 2015 to May 1. The test tools were Jebson-Taylor Hand Function Test, Hand Strength & Pinch, Grooved Pegboard Test, Box & Block and Balance Test. Results. Right dominant hand was higher than left dominant in hand grip and dexterity, hand manipulation skills. And one leg standing and toe standing were higher left foot than right foot dominant. Conclusion. Most of all evaluation items showed a better result right dominant hand than left dominant. But shows that there is no functional difference between left-hand dominant than right-hand. So left-hand dominant coordination was evaluated by a better than right-handed.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.96-99
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• 2002

In order to determine the in-plane shear properties of unidirectional carbon fiber reinforced aluminum laminate composites, a new Iosipescu shear test fixture was developed, by using a fixture undergoing tensile force for the specimen edge to be subjected to compressive loads assumption, under plane stress. Also, to compare the results, Iosipescu shear test method by the modified Wyoming fixture and the off-axis tensile test were performed to determine the shear properties. Off-axis tension test was performed by using new oblique-shaped tabs proposed by Sun and Chung. [5] The oblique tabs reduced remarkably end-constraint effects of off-axis specimens with a aspect ratio of about eight. It is observed through the experimental results show that there is no significant difference between off-axis test results and those of Iosipescu shear test.

• The Journal of Korean Physical Therapy
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• v.35 no.6
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• pp.185-189
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• 2023

Purpose: This study investigated the immediate biomechanical effects of unilateral mastication for 10 minutes on the temporomandibular joint (TMJ) with 21 healthy adult participants. Methods: The gum group chewed gum on the right side for 10 minutes, and the control group rested for 10 minutes. Biomechanical data were obtained using a three-dimensional infrared camera before and after intervention. An independent t-test assessed the variation of kinematic data to identify differences between before and after intervention. Results: Among biomechanical variables, the gum group's length of the left forehead middle region and the temporomandibular joint angle decreased compared to the control group (p<0.05). Conclusion: Caution with unilateral masticatory activity is recommended, as unilateral mastication causes biomechanical changes due to excessive load on the soft tissues of the contralateral TMJ.

• Tribology and Lubricants
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• v.31 no.2
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• pp.56-61
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• 2015

In this study, we investigated the effectiveness of an ultrasonic nanocrystal surface modification (UNSM) technique on the mechanical and wear properties of tungsten carbide (WC). The UNSM technique is a newly developed surface modification technique that increases the mechanical properties of materials by severe plastic deformation. The objective of this study was to improve the wear resistance of press die made of WC by applying the UNSM technique. We observed the microstructures of the untreated and UNSM-treated specimens using a scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX) was used to investigate the chemical composition. The SEM observations showed the pore size and the number of pores decreased after the UNSM treatment. We assessed the wear behavior of both the untreated and UNSM-treated specimens using a scratch test. The test results showed that the wear resistance of the UNSM-treated specimens increased by about 46% compared with the untreated specimens. This may be attributed to increased hardness, reduced surface roughness, induced compressive residual stress, and refined grain size following the application of the UNSM technique. In addition, we found that the UNSM treatment increased the carbon concentration to 63% from 33%. We expect that implementing the findings of this study will lead to an increase in the life of press dies.

• Journal of Ocean Engineering and Technology
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• v.13 no.4 s.35
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• pp.45-54
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• 1999

Non destructive test is applied to revise mechanical strength and assume material strength or defect of material, equipment and structure, instead of fracture test. Especially, ultrasonic test has the characteristics such as an excellent permeability high-sensitiveness to fine defect and an almost exact measurement for position, size and direction of inner defect which differ from other non destructive tests. In this study, the program is developed to evaluate optimal testing condition, to distinguish obstacle echo and defect position. This program on the basic of Ray-Tracing model shows generation and processing of ultrasonic pulse. The simulation is compared with testing in the 3 cases of an oblique angle transducer like $45^{\circ},\;60^{\circ}\;and\;70^{\circ}$. The test result for all conditions is well compared with simulation result when relative not is within $0.1{\sim}7.2%$. And the course of several echos is simply assumed through simulation.

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.778-783
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• 2012

The synthetic short-circuit making test to adequately stress the circuit breaker has been specified as the mandatory test duty in the IEC 62271-100. The purpose of this test is to give the maximum pre-arcing energy during making operation. And this requires the making operation with symmetrical short-circuit current that is established when the breakdown between contact gap occurs near the crest of the applied voltage. Also, if the interrupting chamber of circuit breakers is designed as the type of common enclosure or the operation is made by the gang operated mechanism that three-phase contacts are operated by one common mechanism, three-phase synthetic making test is basically required. Therefore, several testing laboratories have developed and proposed their own test circuits to properly evaluate the breaker performance. With these technical backgrounds, we have developed the new alternative three-phase making circuit.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.393.1-393
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• 2002

Offices and other multipurpose buildings commonly have suspended ceilings installed over room dividing wall. But Korean Standards don't include any code on test methods and test facility of the suspended ceiling system. Therefore, test methods and test facility from ISO and ASTM have been used for evaluating sound performance in domestic so far. In this study, Korean Standards draft on test methods and test facility of suspended ceiling system and materials is proposed on the basis of ISO and ASTM.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.932-935
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• 2007

According to Urban Railroad Act, trains can be operated only after they take The Urban Transit Performance Test. There has been Performance Tests for the trains which has been manufactured since 2000, but it is nearly impossible to utilize the Performance Test results other than the original purpose due to the fact that they are not organized in detail, In addition, test steps have difficulty using the former test results. Thus, test results must be computerized and made into database to make the best use of them and to carry out efficient and dependable tests. For this purpose, this paper analyzes the task and the procedure of the performance test on trains. On the basis of the analysis results, this paper checks the availability of the computerized information and the possibility of improving the task concerned

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.2 s.17
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• pp.126-135
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• 2004

The KSR-III rocket developed by KARI is the first rocket vehicle which is adopting the liquid propellant rocket engine system in Korea and its flight test was successfully done last year, KSR-III is a sounding rocket class launch vehicle, but there is a sense to accomplish design, manufacture, performance test and finally its flight test by domestic technology. In this paper, the authors are intended to introduce the multi-purpose test facility(PTA-II Test Facility) which is constructed for the variety of tests on KSR-III feeding system(single component tests, verification tests, cold flow tests and combustion tests) and its firing test results.