• Journal of Advanced Marine Engineering and Technology
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• v.27 no.3
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• pp.447-452
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• 2003

Crevice corrosion is localized form of corrosion usually associated with a stagnant solution on the micro-environmental level. Such stagnant micro environments tend to occur in crevices (shielded areas) such as those formed under gaskets washers insulation material. fastener heads. surface deposits. disbonded coatings. threads. lap joints and clamps. Crevice corrosion is initiated by changes in located electrochemical reaction within the crevice such as a) depletion of inhibitor in the crevice b) depletion of oxygen in the crevice c) a shift to acid conditions in the crevice and d) build-up of aggressive ion species (e.g chloride) in the crevice. In this study. the mechanism of crevice corrosion for Type 430 stainless steel is investigated undercondition that the size of specimen is $15{\times}20\{times}3mm$, in 1N $H_2SO_4$ + 0.05N NaCl solution. and the artificial crevice gap size of 3 x 0.2 x 15 mm. Crevice corrosion is measured under applied potential -300mV(SCE) to the external surface. The obtained result of this study showed that 1) the induced time for initiation of crevice is 750 seconds. 2) potential of the crevice was about from -320mV to -399mV. which is lower than that of external surface potential of -300mV It is considered that potential drop in the crevice is one of mechanisms for the crevice corrosion

• Acta Via Serica
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• v.2 no.1
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• pp.65-84
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• 2017

Media has become an inseparable companion of $21^{st}$ century culture, exerting immense influence on our daily lives. This article aims to reveal how cultural aspects and media in a particular part of the Silk Road have adapted Western cannons. Iran has redefined and transformed Western culture through the modern Silk Road by the method of cinematic adaptation. Karim-Masihi employs the general plot of Hamlet, the well-known drama by William Shakespeare (1564-1616), in his movie Tardid (Doubt 2009); however, he transforms some of the characters to reflect the current socio-cultural aspects of Iranian society. One of the characters is named Siavash, whose life is similar to Hamlet. In passivity, he awaits his imminent death and other tragic consequences. Yet, the movie ends differently. It is not an Elizabethan tragedy in a strict sense, although the final scenes abound with corpses. This article aims to find the similarities and differences between the two works, while reasoning the significance of the alterations. It concludes with how different cultures react to the same themes.

• Journal of Mechanical Science and Technology
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• v.17 no.10
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• pp.1443-1449
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• 2003

Primary goal of adaptive observers would be to estimate the true states of a plant. Identification of unknown parameters is of secondary interest and is achieved frequently with the persistent excitation condition of some regressors. Nevertheless, two problems are linked to each other in the classical approaches to adaptive observers; as a result, we get a good state estimate once after a good parameter estimate is obtained. This paper focuses on the state estimation without parameter identification so that the state is estimated regardless of persistent excitation. In this direction of research, Besancon (2000) recently summarized that most of adaptive observers in the literature share one common canonical form, in which unknown parameters do not affect the unmeasured states. We enlarge the class of linear systems from the canonical form of (Besancon, 2000) by proposing an adaptive observer (with additional dynamics) that allows unknown parameters to affect those unmeasured states. A recursive algorithm is presented to design the proposed dynamic observer systematically. An example confirms the design procedure with a simulation result.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.207-213
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• 2019

Corrosion and mechanical behavior of the hot-rolled 0.5%Gd-0.8%B-stainless steel to develop a spent nuclear fuel storage material was studied in a simulated nuclear waste treatment condition with rolling condition. The austenite and ferrite phases of the 0.5%Gd-0.8%B-stainless steels are about 88:12. The average austenite and ferrite grain size of the plane normal to rolling, transverse and normal directions of the hot rolled specimens are about 5.08, 8.94, 19.35, 23.29, 26.00 and 18.11 [${\mu}m$], respectively. The average micro-hardness of the as-cast specimen is 200.4 Hv, whereas, that of the hot-rolled specimen are 220.1, 204.7 and 203.5 [$H_v$] for the plane normal to RD, TD and ND, respectively. The UTS, YS and elongation of the as-cast and the hot-rolled specimen are 699, 484 [MPa], 34.0%, and 654, 432 [MPa] and 33.3%, respectively. The passivity was observed both for the as-cast and the hot rolled specimens in a simulated nuclear waste solution. The corrosion potential and corrosion rate of the as-casted specimens are $-343[mV_{SHE}]$ and $3.26{\times}10^{-7}[A/cm^2]$, whereas, those of the hot rolled specimens with normal to ND, RD and TD are -630, -512 and -620 [$mV_{SHE}$] and $6.12{\times}10^{-7}$, $1.04{\times}10^{-6}$ and $6.92{\times}10^{-7}[A/cm^2]$, respectively. Corrosion tends to occur preferentially Cr and B rich area.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.333-335
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• 2006

Position of surface objects can be fixed in many ways. The most popular radionavigational systems, including satellite systems, make possible obtaining nearly continuous and very precise ship's position. However, under the water application of radionavigational systems is impossible. Underwater navigation requires other tools and solutions then these encountered in surface and air navigation. In underwater environment vehicles and submarines, operate that have to possess alternative navigational systems. Underwater vehicles, in order to perform their tasks require accurate information about their own, current position. At present, they are equipped with inertial navigational systems (INS). Accuracy of INS is very high but in relatively short periods. Position error is directly proportional to time of working of the system. The basic feature of INS is its autonomy and passivity. This characteristic mainly decides that INS is broadly used on submarines and other underwater vehicles. However, due to previously mentioned shortcoming i.e. gradually increasing position error, periodical calibration of the system is necessary. The simplest calibration method is surface or nearly surface application of GPS system. Another solution, which does not require interruption of performed task and emergence on the surface, is application of comparative navigation technique. Information about surrounding environment of the ship, obtained e.g. by means sonic depth finder or board sonar, and comparing it with accessible pattern can be used in order to fix ship's position. The article presents a structure and a description of working of underwater vehicle navigation system simulator. The simulator works on the basis of comparative navigation methods which exploit in turn digital images of echograms and sonograms. The additional option of the simulator is ability to robust estimation of measurements. One can do it in order to increase accuracy of position fixed with comparative navigation methods application. The simulator can be a basis to build future underwater navigation system.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.5
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• pp.495-501
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• 2005

Al is a active metal that owes its resistance to a thin, protective, barrier oxide surface layer, which is stable in air and neutral aqueous solution. Thus Al alloys are widely used in architectural trim. cold & hot-water storage vessels and piping. However Al and most of its alloy may corrode with some forms such as pitting corrosion, intergranular corrosion and galvanic corrosion in the case of exposure to various industrial and marine atmosphere. Therefore a correct evaluation of corrosion resistance for their Al and Al alloys may be more important in a economical point of view. In this study. a relative evaluation of corrosion resistance for three kinds of Al alloys such as ALDC2, ALDC3, and ALDC8 series was carried out with electrochemical method. There is a tendency that corrosion potential is shifted to positive or negative direction by alloying components regardless of corrosion resistance. Moreover the data of corrosion properties obtained from cathodic Polarization curve, cyclic voltammogram and AC. DC impedance respectively showed a good correspondence each other against the corrosion resistance but variation of corrosion potential. passivity current density of anodic polarization curve and corrosion current density by Tafel extrapolation and Stern-Geary method didn't correspond with not only each other but also considerably the data of corrosion properties discussed above. Therefore it is suggested that an optimum electrochemical evaluation for corrosion resistance of Al alloy is to calculate the diffusion limiting current density of cathodic polarization curve, impedance of AC or DC and polarization resistance of cyclic voltammogram.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.5 no.2
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• pp.1-6
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• 2009

Nuclear power plants (NPP) using Alloy 600 (Ni 75wt%, Cr 15wt%, Fe 10wt%) as a heat exchanger tube of the steam generator (SG) have experienced various corrosion problems by ageing such as pitting, intergranular attack (IGA) and stress corrosion cracking (SCC). In spite of much effort to reduce the material degradations, SCC is still one of important problems to overcome. Especially lead is known to be one of the most deleterious species in the secondary system that cause SCC of the alloy. Even Alloy 690 (Ni 60wt%, Cr 30wt%, Fe 10wt%) as an alternative of Alloy 600 because of outstanding superiority to SCC is also susceptible to leaded environment. An oxide on SG tubing materials such as Alloy 600 and Alloy 690 is formed and modified expanding to complex sludge throughout hideout return (HOR) of various impurities including Pb. Oxide formation and breakdown is requisite for SCC initiation and propagation. Therefore it is expected that an oxide property such as a passivity of an oxide formed on steam generator tubing materials is deeply related to PbSCC and an inhibitor to hinder oxide modification by lead efficiently can be found. In the present work, the SCC susceptibility obtained by using a slow strain rate test (SSRT) in aqueous solutions with and without lead was discussed in view of the oxide property. The oxides formed on Alloy 600 and Alloy 690 in aqueous solutions with and without lead were examined by using a transmission electron microscopy (TEM), an energy dispersive x-ray spectroscopy (EDXS), an x-ray photoelectron spectroscopy (XPS) and an electrochemical impedance spectroscopy (EIS).

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.180-187
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• 2021

This thesis explores the place and role of a performer's action from a perspective of a director and playwright David Mamet's concept for performer training. This thesis takes inspiration from the idea of Mamet's simple and practical investigation specifically in text-based approach with a performer's bodily function on stage. For Mamet, the writings and practices of many different body-centered training are not rooted in the principle and nature of acting/performance. Reconsidering complicated approaches particularly psychological-oriented theory, practice, and assumption draw on several practitioners takes us beyond the field of visible and/or outer appearance of a performer which in turn leads the performer's body to be as abstract therefore not to being in the moment on stage. Arming the points, we argue that whatever disciplines and/or methods necessarily need to meet the principles and demands of acting/performance/theatre to connect to the materials, an action/objective given by a specific playwright which the performer must inhabit through his/her body. Out of the context, any 'method' serves no purpose. That is, the mechanics of an action is an extension of addressing what a performer's specific needs which shifts his/her body to respond appropriately to the theatrical demands. Taking this argument further, we claim that the purpose of performer training should not be understood as learning and improving techniques or skills for his/her self-perfection. The research finding shows that this resembles to the phenomenon that the visible very often precedes the invisible where the performer's body lose a clarity with no more chance to happen and/or change the event(s). Rather, it is a process of learning what/how to learn which in turn brings us back to the central question of why we do training for what purpose in this contemporary era. Exploring and answering these questions is not only a way to employ the key materials applicable to the theatrical demands but also to achieve the identify as a professional performer/doer on stage.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.138-144
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• 2016

Titanium is resistant to general corrosion and in sea water because of the passivity layer film on the surface of material, but may be attacked by environments that cause breakdown of the protective oxide layer including hydrochloric, sulfuric and phosphoric acids. In this study, the Ti alloys were solution heat treatment 5hours at $1066^{\circ}C$ and $966^{\circ}C$, and followed by aging heat treated, 1, 4, 8 and 16 hours in $500^{\circ}C$, $600^{\circ}C$ and $650^{\circ}C$ respectively. The heat treated specimens were measured micro Vicker's hardness, and then accomplished electrochemical polarization test for comparing corrosion in 1N sulfuric acid solution. Additionally, micro structures were taken for corrosion tested specimens. The results showed that corrosion resistance was higher in solution heat treated alloy than base and age heat treated metal. Measured corrosion resistants were increased as increasing aging heat treatment time and temperature.

• The Journal of the Acoustical Society of Korea
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• v.31 no.4
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• pp.235-243
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• 2012

This paper studies characteristics and causes of sound, and many others by distinguishing passivity and activity of the cases of a dog vocalizing human's words. As a result of the previous cases of vocalization of human's words, the dog was able to understand characteristics of a host's voice and imitate the sound using his own vocal organs. This is the case of passive vocalization accompanied by temporary voice imitation without a function of communication. On the contrary, as a consequence of the recently reported case in which a dog vocalizes such words as "Um-ma" and "Nu-na-ya," it shows the vocalization pattern clearly distinguished from the prior cases. The given dog repeatedly vocalizes pertaining words in an active manner according to circumstances and plays a role of fundamental communication and interaction with its host. The reason why the dog can vocalize the man's words actively is determined to be that the dog has a high level of intelligence and intimacy with its host, that people react actively to its pertaining pronunciation, and so forth. The following results can be used for the study that investigates animals' sound with vocalization possibility and language learning feasibility.