• Proceedings of the KSME Conference
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• 2004.04a
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• pp.31-35
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• 2004

The speed competition of optical disk drive has been accelerated with the fast advancement of its storage density and data transmission technology. The continuous increase of the spinning speed of CD meets the unexpected and catastrophic failure of disk during the operation. The effect of its thickness and outer radius of disk were investigated to reduce stresses and J-integral around the crack tip. The effect of its thickness was considered ahead of the crack tip. In the effect of outer radius of disk, linear elastic fracture mechanics was used to obtain the critical crack length, which indicates the onset length for unstable crack growth. This approach is so significant as to detect the growing crack by disk drive before the catastrophic failure, which will provide the standard size of its safety for high-speed disk drive.

• Journal of Pharmacopuncture
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• v.3 no.2
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• pp.41-54
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• 2000

This study was undertaken to determine if Plantaginis Semen Herbal Acupuncture(PSA) has a protective effect against glycerol-induced acute renal failure in rats. Rats were dehydrated for 24hr and then injected with 8 ml/kg of $50\%$ glycerol, one-half of dose in each hindlimb muscle. In experiments for PSA effect, rats received 0.1 ml of PSA extraction in both sides of corresponding Shenso($BL_{23}$) of human body for 3 days after injection of glycerol. The experimental group were di vided into the Normal group, the Control group, the PSA group. Glycerol injection decreased glomerular filtration rate and increased urine volume, serum creatinine, BUN level and fractional excretion of glucose, $Na^+$, $K^+$ and $CI^-$. These result show that glycerol injection result in acute renal failure. PSA significantly increased glomerular filtration rate and significantly decreased serum creatinine, BUN level and fractional excretion of glucose, $Na^+$ and $CI^-$ as compared Control group. This suggests that PSA could be used in prevention and treatment of acute renalfailure. However, the precise mechanisms of PSA protection remain to be determined.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.332-340
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• 2016

A design optimization is performed for the double-bolted joint in cylindrical composite structures by using a simplified analytical method. This method uses failure criteria for the major failure modes of the bolted composite joint. For the double-bolted joint with a zigzag arrangement, it is necessary to consider an interaction effect between the bolt arrays. This paper proposes another failure mode which is determined by angle and distance between two bolts in different arrays and define a failure criterion for the failure mode. The optimal design for the double-bolted joint is carried out by considering the interactive net-tension failure mode. The genetic algorithm (GA) is adopted to determine the optimized parameters; bolt spacing, edge distance, and stacking sequence of the composite laminate. A purpose of the design optimization is to maximize the burst pressure of the cylindrical structures by ensuring structural integrity. Also, a progressive failure analysis (PFA) is performed to verify the results of the optimal design for the double-bolted joint. In PFA, Hashin 3D failure criterion is used to determine the ply that would fail. A stiffness reduction model is then used to reduce the stiffness of the failed ply for the corresponding failure mode.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.360-365
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• 2009

In the manufacture of CFRP(Carbon Fiber Reinforced Polymer Composite) composite structures, various independent components join by bolts and pins. Holes for bolts and pins have an effect on the failure strength of such structures, because those act as notches in structures. The failure characteristic of such structures are different from those of plain plate subject to remote load. In this paper, tensile properties of woven CFRP composite plates with laminates of $0^{\circ}$, $30^{\circ}$ and $45^{\circ}$ were obtained according to ASTM D 3039. By using obtained tensile failure strength and Tan-Cheng failure criterion, tensile failure strength of CFRP laminate with arbitrary fiber angle were evaluated. Also, the degradation of tensile properties by center hole(${\phi}10mm$) with a remote load was evaluated and the failure strengths were applied to Tan's failure criterion, similarly.

• Fashion & Textile Research Journal
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• v.24 no.2
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• pp.183-194
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• 2022

This study aims to understand the consumers' negative responses to communication failure of chatbots caused by their imperfections. Specifically, this study examines 1) the relationship among chatbot's communication failure, dissatisfaction, negative behavior (complaint, negative word-of-mouth (nWOM), and inertia); 2) the moderating effect of technostress on the relationship between chatbot's communication failure and dissatisfaction; 3) the differences in the negative responses between the generation MZ and the previous generations. Data were collected via an online survey. First, the participants interacted with the chatbot developed for this survey, to experience the chatbot's communication failure. Thereafter, they responded to a questionnaire. PLS-SEM was conducted using the R software environment to test the hypotheses. This study empirically identified that chatbot's communication failure positively affected dissatisfaction. In addition, the customers who were more dissatisfied with the chatbot's communication failures were more likely to complain than engage in nWOM. Compared to the generation MZ, chatbot's communication failure caused a higher level of dissatisfaction in previous generations. The results suggest that online shopping malls should carefully introduce an improved chatbot service after minimizing its communication failure rate. The chatbot developers of online shopping malls targeting middle-aged and elderly consumers should strive to develop and implement strategies to further alleviate consumers' dissatisfaction in the situation of chatbot's communication failure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.754-761
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• 2005

The 40\% of wall thickness criterion which has been used as a plugging rule of steam generator tubes is applicable only to a single cracked tube. In the previous studies performed by authors, several global failure prediction models were introduced to estimate the failure loads of steam generator tubes containing two adjacent parallel axial through-wall cracks. These models were applied for thin plates with two parallel cracks and the COD base model was selected as the optimum one. The objective of this study is to verify the applicability of the proposed optimum global failure prediction model for real steam generator tubes with two parallel axial through-wall cracks. For the sake of this, a series of plastic collapse tests and finite element analyses have been carried out fur the steam generator tubes with two machined parallel axial through-wall cracks. Thereby, it was proven that the proposed optimum failure prediction model can be used as the best one to estimate the failure load quite well. Also, interaction effects between two adjacent cracks were assessed through additional finite element analyses to investigate the effect on the global failure behavior.

• Journal of Astronomy and Space Sciences
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• v.28 no.2
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• pp.133-141
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• 2011

A satellite power system should generate and supply sufficient electric power to perform the satellite mission successfully during the satellite mission period, and it should be developed to be strong to the failure caused by the severe space environment. A satellite power system must have a high reliability with respect to failure. Since it cannot be repaired after launching, different from a ground system, the failures that may happen in space as well as the effect of the failures on the system should be considered in advance. However, it is difficult to use all the hardware to test the performance of the satellite power system to be developed in order to consider the failure mechanism of the electrical power system. Therefore, it is necessary to develop an accurate model for the main components of a power system and, based on that, to develop an accurate model for the entire power system. Through the power system modeling, the overall effect of failure on the main components of the power system can be considered and the protective design can be devised against the failure. In this study, to analyze the failure mode of the power system and the effects of the failure on the power system, we carried out modeling of the main power system components including the solar array regulator, and constituted the entire power system based on the modeling. Additionally, we investigated the effects of representative failures in the solar array regulator on the power system using the power system model.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3236-3246
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• 2021

Lessons learned from the Fukushima Daiichi nuclear power plant accident directed that multiple failures should be considered more seriously rather than single failure in the licensing bases and safety cases because attempts to take accident management measures could be unsuccessful under the high radiation environment aggravated by multiple failures, such as complete loss of electric power, uncontrollable loss of coolant inventory, failure of essential safety function recovery. In the case of the complete loss of electric power called station blackout (SBO), if there is no mitigation action for recovering safety functions, the reactor core would be overheated, and severe fuel damage could be anticipated due to the failure of the active heat sink. In such a transient condition at CANDU-6 plants, the seal failure of the primary heat transport (PHT) pumps can facilitate a consequent increase in the fuel sheath temperature and eventually lead to degradation of the fuel integrity. Therefore, it is necessary to specify the regulatory guidelines for multiple failures on a licensing basis so that licensees should prepare the accident management measures to prevent or mitigate accident conditions. In order to explore the efficiency of implementing accident management strategies for CANDU-6 plants, this study proposed a realistic accident analysis approach on the SBO transient with multiple-failure sequences such as seal failure of PHT pumps without operator's recovery actions. In this regard, a comparative study for two PHT pump seal failure modes with and without coolant seal leakage was conducted using a best-estimate code to precisely investigate the behaviors of thermal-hydraulic parameters during transient conditions. Moreover, a sensitivity analysis for different PHT pump seal leakage rates was also carried out to examine the effect of leakage rate on the system responses. This study is expected to provide the technical bases to the accident management strategy for unmitigated transient conditions with multiple failures.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.4
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• pp.145-153
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• 2014

This study examined the linkage between positive cognitive bias and entrepreneurial intention. Self-enhancement, unrealistic optimism, and illusion of control have been collectively referred as positive cognitive bias. We examined the effects of positive cognitive bias on attitudes toward success and failure. And we also examined the effect of attitudes toward success and failure on entrepreneurial intension. This study investigated these relationships using 240 high school students. The result of analysis indicated that the self-enhancement bias and unrealistic optimism bias had positive effects on attitude toward failure, but it had not any effect on attitude toward success. The illusion of control bias has positive effects on attitude toward success, but it had not any effect on attitude toward failure. The attitudes toward success and failure had positive effect on entrepreneurial intension. Then results of this study suggests that the cognitive biases showed a role of antecedents of attitudes toward success and failure. Finally, this study concluded with a discussion of the implications of the research findings and directions for future research.

• Culinary science and hospitality research
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• v.16 no.2
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• pp.15-30
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• 2010

This study investigates the effect of seriousness and controllability of service failure on perceived fairness, reliability, satisfaction and loyalty of customers. The result of the study is as follows. First, it was expected that a control-attribute and a seriousness-attribute would have an negative(-) impact on perceived fairness-attribute; however, the result showed that both did not have an negative impact on it. Next, a fairness-attribute of a procedure had a significant effect on trust, and a fairness-attribute of interaction and a fairness-attribute of distribution had a significant effect on trust and satisfaction. Lastly, trust had a significant effect on satisfaction while satisfaction had a significant effect on loyalty. Based of the result of this study, food-service enterprises need to perform a fast process of a recovery to overcome service failure rather than confirming a control-attribute and a seriousness-attribute of service failure. Also, they should set up a process of the recovery in the order of trust, satisfaction, and loyalty and check if this process is promptly carried out.