• Journal of the Korean Society of Safety
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• v.27 no.6
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• pp.48-53
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• 2012

This paper is purposed to develop portable electric instrument to select NI-9223(National instrument comp.) and clamp meter(HIOKI comp.), which can be used in developing electric instrument, to detect leakage current(ZCT) and current(CT) signals. In this paper, The electric instrument that can interface with current and leakage current instrument(HIOKI 9283), is developed by NI-9223 of NI comp.. HIOKI clamp meter can measure current signals certainly by high-sensitivity of 10 ${\mu}A$ resolution(leakage current : at 10 mA range) and current 1~200A range. The NI-9223 use four 16-bit analog-to-digital converters(ADCs) for true simultaneous sampling at up to 1 MS/s per channel. NI-9223 can synchronize all analog input modules installed in the same chassis to share the same start clock and/or sample clocks. The monitoring program is developed by SignalExpress of LabVIEW. The monitoring program are developed to analyze at simultaneous sampling on electrical signals such as leakage current(ZCT) and current(CT). The developed system verification tests were conducted, and portable electric instrument can be used in place which requires analysis of the actual electrical signal.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.4 s.19
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• pp.29-36
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• 2005

In this study, relations among unconfined compressive strength, strain at maximum strength and depth were compared with each other. Test specimen is marine clay originated from the place near Ga-duck island in Busan city. In addition, influence of impure material contained in specimen and that of total core recovery(TCR) on unconfined compressive strength and degree of disturbance were investigated. As a result of tests, unconfined compressive strength decreases as strain corresponding to maximum strength increases. Also, the deeper the sampling depth and the bigger the TCR, the unconfined compressive strength increases. Especially, as the TCR increases, the unconfined compressive strength Increases and quality of specimen is enhanced.

• Asia pacific journal of information systems
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• v.31 no.4
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• pp.448-471
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• 2021

Compared to consumers' focus, in the past, on the functional aspect of fashion products, consumers recently tend to place more importance on their impressive and memorable experiences in purchasing process. As consumer's interest changes from functional aspects to individual experience in purchasing process, fashion brands try to convey the identity of the brand through creating favourable consumers' experiences. Therefore, this study explores the effect of individuals' aesthetic experiences with fashion brands' SNS accounts on their attitudes. More specifically, the study evaluates whether consumers enjoy the flow of fashion brands' SNS accounts and form purchase intentions through their aesthetic experiences and product placement. Through a survey, empirical testing was done to investigate the effect of the aesthetic experience on of flow and purchase intentions. The current study tests the interaction effect among perceived aesthetic experience, narrative images, and product placement employing 2×2×2 MANOVA. The findings herein reveal that the aesthetic experience affects flow and purchase intention, and that there is a statistically significant interaction effect between aesthetic experience, narrative images, and product placement.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.389-392
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• 1999

Fatigue is a process of progressive permanent internal structural change in a material subjected to repeitive stresses. These change may be damaging and result in progressive growth of cracks and complete fracture if the stress repetitins are sufficiently large. For structural members subjected to cyclic loads, the continuous and irrecoverable damage processes are taking place. These processes are referred as the cumulative damage processes due to fatigue loading. Moreover, increased use of high strength concrete makes the fatigue problem more important because the cross-section and dead weight are reduced by using high strength concrete. The purpose of this study is to investigate the shear fatigue behavior of reinforced concrete beams according to shear reinforcement ratio and concrete compressive strength under repeated loadings. For this purpose, comprehensive static and fatigue tests of reinforced concrete beams were conducted. The major test variables for the fatigue teats are the concrete strength and the amount of shear reinforcements. The increase of deflections and steel strains according to load repetition has been plotted and analyzed to explore the damage accumulation phenomena of reinforced concrete beams. An analytical model for shear fatigue behavior has been introduced to analyze the damage accumulation under fatigue loads. The failure mode and fatigue lives have been also studied in the present study. The comparisons between analytical results and experimental data show good correlation.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.24-29
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• 2003

Deep sea water has cold temperature, abundant nutrients and minerals, and good water quality that is pathogen-free and stable. Compared with surface water, deep sea water contains more nutrition salt, such as nitrogen and phosphor. Moreover, if has the good balance of minerals. Because of the ability of the spray drying process to produce a free-flowing power considering of spherical particles with a well-defined size distribution and the rapid drying times for heat-sensitive material, spray drying is attractive for a wide range of applications spray drying is a unique unit operation in which powders are produced from a liquid feed in a single processing step. Key component of the process are atomizer, spray chamber. Design of spray chamber should be based on the atomizer type, the production rate, and the particle size required. Because of the complex processes taking place during spray drying, traditional design method are based on pilot-plant tests and empirical scale-up rules. Modern technique such as CFD have a role to play in design and troubleshooting.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.127-134
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• 2010

Components in thermal power plants are subjected to service conditions under which creep damages take place causing material exhaustion. Comprehensive creep damage investigations have been performed on a 0.5Cr0.5Mo0.25V pipe bend which had been taken out of service after 117,603h and 501 start-ups because of severe cracks. The propagation of creep damage in a long term exposed pipe bend has been analysed by the replication, Indentation and hardness tests. Also, Calculation of creep lifetime has been investigated in order to verify actual lifetime of a damaged pipe bend. By measuring diametrical expansion, Accumulated creep strain and creep strain rate were calculated. Calculated results of creep lifetime on the Larson-Miller Parameter method are good agreement with actual service-exposed hour.

• Composites Research
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• v.23 no.1
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• pp.17-22
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• 2010

The compressive and dynamic properties of magnetorheological elastomers were investigated as functions of magnetizable particle volume fraction, alignment of the embedded particle and magnetic force. The specimens consisted of pure and filled silicons with randomly dispersed, longitudinal and transverse aligned magnetizable particle chains. To align the embedded particles in the elastomer, the cross-linking of the elastomer composites took place in a magnetic field. The compression and dynamic tests in the absence and the presence of different magnetic forces were carried out. The modulus and loss factor of the elastomer composites increase with increasing volume fraction at the same magnetic force. The case of longitudinal alignment shows a high modulus and loss factor when compared to the case of transverse alignment or random dispersion.

• Composites Research
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• v.23 no.4
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• pp.21-27
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• 2010

In most engineering structures, fracture often takes place due to fatigue. Therefore, many studies about the effect of the various mode-mixities on fatigue characteristics have been performed. However, most of the former studies only address metal/metal interfaces or delamination of composite. In this study, the fatigue characteristics of composite/metal interfaces are investigated. The fatigue tests were performed using single leg bending(SLB)specimens that comprise composite and steel bonded to each other using co-cure bonding method. This paper focuses on fatigue characteristics depending on different mode ratios$(G_{II}/G_T$. The overall results obtained in this study show that the crack propagation rate increases with the mode II loading component.

• Structural Engineering and Mechanics
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• v.65 no.3
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• pp.349-357
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• 2018

An extensive research was undertaken to study the vibration serviceability of a long-span and light-weight floor subjected to human loading experimentally and numerically. Specifically, heel-drop test was first conducted to capture the floor's natural frequencies and damping ratios, followed by jumping and running tests to obtain the acceleration responses. In addition, numerical simulations considering walking excitation were performed to further evaluate the vibration performance of a multi-panel floor under different loading cases and walking rates. The floor is found to have a high frequency (11.67 Hz) and a low damping ratio (2.32%). The comparison of the test results with the published data from the 1997 AISC Design Guide 11 indicates that the floor exhibits satisfactory vibration perceptibility overall. The study results show that the peak acceleration is affected by the walking path, walking rate, and adjacent structure. A simpler loading case may be considered in design in place of a more complex one.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.210-213
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• 2002

For insulation design of the superconducting transformer, many types of insulation tests should be carried out. To clarify the components of insulation for superconducting transformer, there are main four parts as 1ike that turn-to-turn interior of each primary and secondary windings, layer-to-layer between primary and secondary windings, and winding to grounded structures. The insulation components should meet the required withstand voltage of the system and enough safety factors must included. As the fundamental insulation characteristics, we tested surface flashover voltage of spacer that would place between the coils and would take the role of both cooling duct and insulator. The structure of spacer in practice vary depending on coil type, in this work we considered double pancake coil for the superconducting transformer. In this study we tested flashover voltages of several arrangement of spacer.