• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.3
• /
• pp.269-273
• /
• 2015

The study investigated the effect of the distance between two collinear circumferential surface cracks on the primary stress corrosion crack (PWSCC) growth in alloy 600TT steam generator tubes using a finite element damage analysis based on the PWSCC initiation model and macroscopic phenomenological damage mechanics approach. The damage analysis method was verified by comparing the results to the previous study results. The verified method was applied to collinear circumferential surface PWSCCs. As a result, it was found that the collinear cracks showed earlier coalescence and penetration times than the a single crack, and the times increased with the distance. In addition, it is expected that penetration may occur before coalescence of two cracks if they are more than a specific distance apart.

• Fire Science and Engineering
• /
• v.27 no.6
• /
• pp.89-96
• /
• 2013

The purpose of this study is to check the fire origin and cause of the fire by observing the shape of the flame propagation in air-conditioner indoor unit through the fire tests. We supposed that the flame is spread from the surroundings to the top of the air-conditioner and ignited on top of the air-conditioner with n-heptane. And then repeated this experiment twice under the same conditions. After the ignition, refrigerant filled in air-conditioner and lubricating oil exploded with large explosion and flame having high temperature and pressure belched out rapidly due to bursting refrigerant pipe linked air-conditioner between 734 seconds and 559 seconds. After result of checking the combustion residue we found that almost all of that was lost except a part of the evaporator, motor and metal. The position of short-circuit traces of wiring for the air-conditioner ignited itself is similar to that of fire damage by external flame. Therefore, we verified that it is not certain to determine the ignition cause and point by only the shape of the combustion residues.

• Tribology and Lubricants
• /
• v.32 no.2
• /
• pp.56-60
• /
• 2016

Sapphire has a high hardness and strength and chemical stability as a superior material. It is used mainly as a material for a semiconductor as well as LED. Recently, the cover glass industry used by a sapphire is getting a lot of attention. The sapphire substrate is manufactured through ingot sawing, lapping, diamond mechanical polishing (DMP) and chemical mechanical polishing (CMP) process. DMP is an important process to ensure the surface quality of several nm for CMP process as well as to determine the final form accuracy of the substrate. In DMP process, the material removal is achieved by using the mechanical energy of the relative motion to each other in the state that the diamond slurry is disposed between the sapphire substrate and the polishing platen. The polishing platen is one of the most important factors that determine the material removal characteristics in DMP. Especially, it is known that the geometric characteristics of the polishing platen affects the material removal amount and its distribution. This paper investigated the material removal characteristics and the effects of the polishing platen groove in sapphire DMP. The experiments were preliminarily carried out to evaluate the sapphire material removal characteristics according to process parameters such as pressure, relative velocity and so on. In the experiment, the monitoring apparatus was applied to analyze process phenomena in accordance with the processing conditions. From the experimental results, the correlation was analyzed among process parameters, polishing phenomena and the material removal characteristics. The material removal equation based on phenomenological factors could be derived. And the experiment was followed to investigate the effects of platen groove on material removal characteristics.

• Research in Community and Public Health Nursing
• /
• v.14 no.2
• /
• pp.299-311
• /
• 2003

Purpose: This is a phenomenological study to describe the experiences of nursing students on home visiting nursing service as a community nursing practice. Method: Individual interviews were conducted on subjective experiences of 17 nursing students. Data were analyzed through Colaizzi's method in which meaningful statements were extracted and these were clustered into 6 themes. Result: The nursing students started practice with anxiety and expectation at the same time. They were frightened at the clients' inferior environment and their level of loneliness. They also felt pity and experienced complicated feelings for the clients. However, the home visiting practice was a chance for them to discard prejudice on the clients. Positive experiences on visiting nursing practice reported by the nursing students included lively interactions between nurses and the clients, and variable provision of primary nursing care. However, facts such as much limited visiting time, non-professional and limited scope of practice were reported as negative experiences. They felt both worthiness of the home visit service and restricted self-capability at the same time through the practice. They also felt sorry for the clients because the home visit services were carried out during limited time period. Regardless of this, the home visit experience provided them an opportunity of self-growth. This self-growth includes increased awareness of issues for elderly, building of self-identity as a nursing student, self-reflection, and realization of the value of family. Conclusion: This study may provide data for better understanding of nursing students experiences of home visiting nursing services. However, more study on the barriers of their community health practice is needed in the future. Moreover, it is needed to establish desirable practice environment through the collaborative relationships between the university and staffs in the public health center.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.3
• /
• pp.46-51
• /
• 2018

This study is one of a series of studies exploring the locality of Jeju architecture, in which we focused on the works of domestic architects, rather than those of famous foreign architects, as well as on the locality of the phenomenological aspect rather than the conceptual one, so as to reveal the locality in the present situation. It was revealed that the architects had the following viewpoints with regard to the local characteristics of Jeju: first, the hermeneutic aspect of the locality is the architectural application of the traditional Jeju architecture; second, the phenomenal aspect of the locality involves respect for the landscape and natural scenery of Jeju. There are two main ways in which architects can realize the locality that they envisage. The hermeneutic representation of Jeju would be as a locality consisting of traditional houses. The architects mainly wanted to implement the elements of the private houses through the space layout. The phenomenal representation of the locality would require them to respect the landscape and scenery of Jeju and to implement them in its architecture. This was the case if the landscape or landscape elements were directly borrowed from the buildings, or if the buildings respect the scenery or landscape of Jeju.

• Korean Journal of Human Ecology
• /
• v.23 no.5
• /
• pp.789-805
• /
• 2014

This study is performed to verify immigrant wives' perceived conflicts with mother-in-laws and coping experiences. In order to understand in-depth conflicts between female immigrants and their mother-in-laws, we selected 8 foreign daughter-in-laws who have stayed over 5 years in Korea. We applied van Manen's phenomenological methods. After the data analysis, 7 fundamental themes were derived and these are as follows: First, mother-in-laws as a prison guard, second, living a conscious life of other's eyes, third, annoying words from mother-in-laws, fourth, treat married female immigrants as invisible woman not as family members, fifth, saying we are one finger which can overcome pains from biting, sixth, mother-in-laws can't let her son go, seventh, not distributing love. In addition, coping behaviors were as follows: they just deal with living a conscious life of other's eyes, making a feeble complaints, accepting it with understanding, resisting the situation, evading and enduring the circumstances. Husband was most reliable supporter and secured hiding place. Her friends were her spirit supporters.

• International Journal of Aeronautical and Space Sciences
• /
• v.17 no.4
• /
• pp.518-525
• /
• 2016

This paper presents the characteristics of non-fundamental multi-mode combustion instability and the effects of high-harmonic components on the Rayleigh criterion. Phenomenological observations of multi-harmonic-mode dynamic pressure waves regarding the intensity of harmonic components and the source of wave distortion have been explained by introducing examples of second- and third-order harmonics at various amplitudes. The amplitude and order of the harmonic components distorted the wave shapes, including the peak and the amplitude, of the dynamic pressure and heat release, and consequently the temporal Rayleigh index and its integrals. A cause-and-effect analysis was used to identify the root causes of the phase delay and the amplification of the Rayleigh index. From this analysis, the skewness of the dynamic pressure turned out to be a major source in determining whether multi-mode instability is driving or damping, as well as in optimizing the combustor design, such as the mixing length and the combustor length, to avoid unstable regions. The results can be used to minimize errors in predicting combustion instability in cases of high multi-mode combustion instability. In the future, the amount of research and the number of applications will increase because new fuels, such as fast-burning syngases, are prone to generating multi-mode instabilities.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.10
• /
• pp.1463-1470
• /
• 2010

Microforming, which exploits the advantages of metal forming technology, appears very promising in manufacturing microparts since it enables the production of parts using various materials at a high production rate, it has high material utilization efficiency, and it facilitates the production of parts with excellent mechanical properties. However, the conventional macroscale forming process cannot be simply scaled down to the micro-scale process on the basis of the extensive results and know-how on the macroscale process. This is because a so-called "size effect" occurs as the part size decreases to the microscale. In this paper, we attempt to develop an effective analytical and experimental modeling technique for explaining the effects of the grain size and the specimen size on the behavior of metals in microscale deformation processes. Copper sheet specimens of different thicknesses were prepared and heat-treated to obtain various grain sizes for the experiments. Tensile tests were conducted to investigate the influence of specimen thickness and grain size on the flow stress of the material. In addition, an analytical model was developed on the basis of phenomenological experimental findings to quantify the effects of the grain size and the specimen size on the flow stress of the material in microscale and macroscale forming.

• Journal of the Korea Furniture Society
• /
• v.20 no.6
• /
• pp.543-551
• /
• 2009

The history repeatedly shows that designers have sought their creative inspiration from fine arts. was also influenced by contemporary art such as surrealism or installment works. This thesis aims to examine the inter-relationship between contemporary art and contemporary furniture design with examples of organic modernism and minimalism furniture design. Also, will be analyzed in light of such interdisciplinary relationship, explaining the significances of in scholastic perspective. The previous research analysis of finding out examples of how fine art and design sought mutual exchanges to develop will help to examine the significance of in the context of art history. This analysis could be used as an important academic material to understand the origin and characteristics of modern design furniture. The features of surrealism and minimalism will be discussed in light of their influences on and interactive relationship with organic modernism furniture design. This provides important basic material to further analyze . Furthermore, the artistic language and plastic features of contemporary sculptors and installment artists such as Jean Arp, Richard Serra and Anish Kapoor will be examined to show how integrated and combined main features of those artists. extracted cognitive and phenomenological aspects from Serra's works that overwhelm viewers with their massive scales. Somewhat abstract yet somewhat primitive and dynamic features of Arp's works was also referred to . are made of FRP, composed of three partitions and six stools. This work was analyzed in aspect of form, composition and function. They have organic and flexible formations with free composition availability which endow free disassemble and arrangement. Also, they have cognitive features as of small elements are freely dispersed upon spaces to bestow certain presences. Based on this, this thesis could develop scholastic researches that examine the mutual and interactive relationship between contemporary art and furniture design with much more detailed discussions and examples.

• Journal of Sensor Science and Technology
• /
• v.7 no.6
• /
• pp.386-393
• /
• 1998

We have carried out the measurements of complex dielectric constants with impedance/gain-phase analyzer using capacitor method and the experiments of high temperature X-ray powder diffraction with X-ray diffractometer using ${\theta}-2{\theta}$ scan method for the KTP single crystal which has the premium nonlinear optical properties. From the results of high temperature X-ray powder diffraction experiments, we have found that KTP does not undergo structural phase transition below $900^{\circ}C$. It is clear that KTP undergoes structural phase transition around $900^{\circ}C$ and belongs to orthorhombic above $900^{\circ}C$ still. However, we have applied phenomenological relation of dielectric relaxation to the results of complex dielectric measurement and have found that relaxation mechanism of KTP well satisfies the Cole-Cole relation over the temperature range from $-78^{\circ}C$ to $200^{\circ}C$. And also the relaxation time well satisfies the Vogel-Fulcher relation. It is regarded that the hopping and thermally activated diffusion mechanism may control the conduction behavior of KTP above $200^{\circ}C$.