• Journal of Advanced Marine Engineering and Technology
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• 제25권2호
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• pp.345-345
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• 2001

This paper was studied on the characteristics of galvanic corrosion and its protection on heat exchanger tube plate in the sea water. In this paper, behavior of pitting corrosion of Ni-al bronze connected with Ti tube was measured af flow velocity of 0 m/s and 2.4 m/s. To protect galvanic corrosion, the protection characteristics of Ni-Al bronze connected with Ti tube by Zn-base alloys galvanic anode and hexagonal nylon insert was investigated. Main results obtained asre al follows: 1) The galvanic corrosion of Ni-Al bronze connected with Ti-tube is more active than single Ni-al bronze. 2) As the circuit resistance increase under the cathodic protection employing Zn-base alloys galvanic anode, Ni-al bronze connected with Ti tube is cathodically unpolarized. 3) The corrosion of Ni-Al bronze connected with Ti tube by nylon insert controls approximately 73% than not nylon insert.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.3019-3021
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• 2005

In this paper we suggest a novel temperature detection method utilized in direct over-temperature protection circuit modeling. The suggested model detects temperature variation using Rds(on) characteristics of MOSFET, while the conventional methods are using extra devices such as a temperature sensor or an over-temperature detection transistor. The temperature-dependant MOSFET model is implemented using Spice ABM(Spice Analog Behavior Model). The direct over-temperature protection circuit was designed including it. We verified effectiveness of the temperature dependant Rds(on) model characteristics and performance of the direct over-temperature protection circuit on PSpice simulation

• Journal of Information Technology Applications and Management
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• 제27권2호
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• pp.1-21
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• 2020

The purpose of this study is to investigate the behavioral factors affecting the security attitude and intention to use biometrics password based on the protection motivation theory. This study also investigates security awareness training to understand trust, privacy, and security vulnerability regarding biometric authentication password. This empirical analysis reveals security awareness training boosts the protection motivational factors that affect on the behavior and intention of using biometric authentication passwords. This study also indicates that biometric authentication passwords can be used when the overall belief in a biometric system is present. After all, security awareness training enhances the belief of biometric passwords and increase the motivation to protect security threats. The study will provide insights into protecting security vulnerability with security awareness training.

• Journal of Electrochemical Science and Technology
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• 제9권1호
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• pp.1-8
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• 2018

The effect of mixing ratio on the corrosion protection of carbon steel coated by a film composed of poly(vinylidene) fluoride (PVDF) and poly(methyl methacrylate) (PMMA) was examined using electrochemical impedance spectroscopy. Surface crystallization behavior and thermal properties of the PVDF/PMMA coated carbon steel were evaluated using polarized optical microscopy and differential scanning calorimetry, respectively. A Maltese cross-pattern spherulite crystal was observed in the PVDF/PMMA coating film, which became more apparent with increasing PVDF content. The highest corrosion protection performance was achieved with 60 wt.% PVDF-coated carbon steel, and delamination and corrosion reactions were observed for 20 wt.% PVDF-coated carbon steel. Further, corrosion protection performance with an amorphous/crystal mixture (PVDF/PMMA, 60/40 (w/w)) was better than those observed in the amorphous domain and the perfect-crystal domain of the PVDF/PMMA blended coating system.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2001년도 춘계학술대회 논문집
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• pp.152-157
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• 2001

This paper was studied on the characteristics of crevice corrosion prevention of SS 400 in marine environment. In NaCl solution, polarization behavior under the crevice corrosion was investigated. And Weight loss rate of SS 400 applied cathodic protection and non cathodic protection was measured according to the NaCl concentration. The main results obtained are as follows : The weight loss rate of Al-alloy galvanic anode was increased as the concentration of NaCl solution increased by 3.5% but the concentration increased over 3.5%, that of Al-alloy galvanic anode become decreased. The protective potential of SS 400 used Al-alloy galvanic anode becomes more cathodic polarization with increasing concentration of NaCl solution. Effects of oxygen on the weight loss rate of Al-alloy sacrificial anode for cathodic protection as the concentration of 3.5% NaCl solution become sensitive than that of 0% NaCl solution.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.148-150
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• 2006

This paper describes the overvoltage at the branch line in underground distribution systems when the direct lightning surge strikes on conductor of overhead line. Distribution systems are very complex because it includes many branch lines, transformers, switches and so on. Therefore model system consists of overhead distribution lines, underground cable include branch lines, lightning source and switches. Analysis are performed using EMTP to understand and evaluate the surge behavior on branch lines considering various conditions in underground distribution systems. Simulation results show overvoltage with location in various cases. It is evaluated that result will be used to establish protection methods in actual underground distribution systems.

• Interaction and multiscale mechanics
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• 제3권4호
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• pp.405-414
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• 2010

The performance of full-scale steel and composite bridge safety barriers under vehicle crash is evaluated by using the nonlinear explicit finite element code LS-DYNA. Two types of vehicles used in this study are passenger car and truck, and the performance criteria considered include structural strength and deformation, occupant protection, and post-crash vehicle behavior. It can be concluded that the composite safety barrier satisfies all performance criteria of vehicle crash. Although the steel safety barrier satisfies the performance criteria of occupant protection and post-crash vehicle behavior, it fails to satisfy the performance criterion of deformation. In all performance evaluations, the composite safety barrier exhibits a superior performance in comparing with the steel safety barrier.

• 가정과삶의질연구
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• 제21권5호
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• pp.121-132
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• 2003

This study investigated the current situation regarding college environments and the use of disposable goods, to inquire the environmental consciousness of college student consumers, and to identify factors that affect their use of disposable products. The major findings of this study are summarized in the following. First, college students' usage of disposable products was measured in two ways: the tendency to use disposable product and the quantities of disposable products consumed. The tendency to use disposable product was found to be 2.80/5, which indicates that college students' behavior of consuming disposable goods was less than moderate. On average, a college student consumed a total of 35 disposable products per month. Second, variables that affect college students' consumption of disposable products were investigated. The students who showed a higher tendency to use disposable products were those with more spending money, those without any experiences in the environmental organizations and clubs, those who had a low personal opinion toward university policies, those who regarded environmental protection as more important than economic growth, and those who thought environmental protection to be more important than fashion.

• International Journal of Precision Engineering and Manufacturing
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• 제4권4호
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• pp.45-50
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• 2003

In order to investigate the effect of surface treatment (Anodizing) and rolling on AI 5083-H131 alloy, under hyper velocity impact, a ballistic testing was conducted. Ballistic resistance of these materials was measured by a protection ballistic limit ($V_{50}$)' a statistical velocity with 50% probability of penetration. Perforation behavior and ballistic tolerance, described by penetration modes, were respectfully observed, by $V_{50}$ test and Projectile Through Plates (PTP) test at velocities greater than $V_{50}$. PTP tests were conducted with 0$^{\circ}$ obliquity at room temperature using 5.56mm ball projectiles. $V_{50}$ tests with 0$^{\circ}$ obliquity were also done with projectiles that were able to achieve near or complete penetration during PTP tests. Resistance to penetration, and penetration modes of Al 5052-H34 alloy were compared to those of Al 5083-H 131 alloy.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 추계학술대회 논문집
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• pp.268-268
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• 2015

The corrosion protection behavior of AZ31 magnesium alloy (Mg alloy) with cathodic electrophoretic coating (E-coating) pretreated by cerium-based conversion coatings at various pH was investigated in this study. Cerium-based conversion coatings (CeCCs) were deposited on AZ31 Mg alloy by immersion treatment in the nitrate-based cerium salt solution. The morphology and composition of the CeCCs were analyzed using scanning electron microscopy and energy dispersive X-ray spectroscopy. The corrosion properties of the AZ31 Mg alloy pretreated with cerium coating and subsequently E-coated were studied during salt-spray testing. The surface morphologies of the E-coated Mg alloy were examined in detail after different testing times using digital photography. It was found that the protective properties of the E-coating on AZ31 Mg alloy generated are heavily dependent upon the CeCC factors such as treatment time, coating thickness and pH of the solution.