• Journal of the Korean Society of Clothing and Textiles
• /
• v.41 no.5
• /
• pp.939-949
• /
• 2017

This study uses 3D printing technology to design and fabricate a fall impact protection pad with a spacer fabric structure. The design of the pads consists of hexagonal three-dimensional units connected in a honey-comb shape; in addition, the unit consists of a surface layer and a spacer layer. Protect pads were designed as either a hexagonal type or diamond type according to the surface layer structure; subsequently, a spacer filament was also designed as the most basic I-shape type. Designed pads were printed using four types of flexible filaments to select suitable material for a fall impact protection pad. Impact protection performance and bending stiffness were evaluated for the eight type of pad outputs. As a result of the impact protection performance evaluation, when the force of 6,500N was applied, the force passed through the pad was in the range of 1,370-2,132N. FlexSolid$^{(R)}$ and Skinflex$^{TM}$ showed good protection performance and cubicon flexible filament showed the lowest protection. NinjaFlex$^{(R)}$ was found to be the most flexible in the bending stiffness evaluation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.7 no.1
• /
• pp.9-16
• /
• 2009

Transport package for radioactive material should be structurally safe under puncture drop condition and its safety should be verified by test and numerical analysis. Most finite element analyses for puncture drop have been performed without modeling the impact limiter since failure is occurred in the materials of the impact limiter. This paper presents a new modeling methodology, where an element is eroded in case that the material's failure criteria are reached at the element's integration point, to investigate the effect of the impact limiter in the puncture process. The effectiveness of the proposed scheme is shown through the puncture drop analysis of hotcell transport cask, which is under design in KAERI. The results show that about 80 percent of the total impact energy is absorbed due to the deformation of impact limiter. Using the present method the puncture drop can be analyzed more accurately, but it would give conservative results compared to the actual test condition.

• Korea Journal of Hospital Management
• /
• v.7 no.2
• /
• pp.1-23
• /
• 2002

D. W. Organ(1977) published a paper about the importance of Organizational Citizenship Behavior(OCB) in an organization. Since then, the studies of OCB have been continuously increased. As recent business environment has changed with rapidity and uncertainty, OCB for the improvement performance of organization should be more emphasized. Role behaviors of organization are divided into two parts such as in-role behavior and extra-role behavior. In recent, although the researches about extra-role behavior have been studied, they are still not sufficient. This study attempted to examine relationships between organizational culture, organizational commitment and organizational citizenship behavior, Sample was 193 employee engaged in hospitals of Pusan. In this study I chose four factor(affective, conservative, task and innovative culture) of organizational culture and three factors (affective, continuous and normative commitment) of organizational commitment and five factors(altruism, conscientiousness, courtesy, civic virtue and sportsmanship) with regard to organization citizenship behavior. The major findings of the empirical research are as follows ; 1. The Causal relation of dimensions of organizational culture and dimensions of OCB. 1) Affective culture has significant impact on courtesy, civic virtue of OCB. 2) Conservative culture has no significant impact on all of OCB. 3) Task culture has significant impact on conscientiousness, civic virtue, sportsmanship of OCB. 4) Innovative culture has no significant impact on courtesy, civic virtue of OCB. 2. The Causal relation of dimensions of organizational commitment and dimensions of OCB. 1) Affective commitment has significant impact on all of OCB. 2) Continuous commitment has no significant impact on all of OCB. 3) Normative commitment has significant impact on courtesy, civic virtue of OCB. In brief, though this study has several limitations in research design and methods, the results suggest that organizational culture of hospitals and organizational comitment of hospitals shows a strong relationship to the organization citizenship behavior.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.6
• /
• pp.431-444
• /
• 2012

Constituents of timber framed floor affect the insulation performance against impact sound significantly. Among them, installation of massive sound absorbing layer and reinforcement of stiffness of timber floor have been considered as major factors that improve the insulation performance against impact sound. Researches on evaluating the effect of floor constitutions have been carried out through the field measurements for timber framed buildings in Korea. It is concluded that the impact sound pressure level at the relatively lower frequency governs the overall insulation performance, and can be improved by the installation of sound absorbing layer and reinforcement of floor stiffness. Especially, the insulation performance against heavy impact sound was improved significantly when the massive cement mortar layer for floor heating system was installed and the stiffness was reinforced by shortening the joist span using additional beam at the mid-position of original span.

• Advances in aircraft and spacecraft science
• /
• v.1 no.2
• /
• pp.233-251
• /
• 2014

Each aircraft have to be certified for a specified level of impact energy, for assuring the capability of a safe flight and landing after the impact against a bird at cruise speed. The aim of this research work was to define a scientific and methodological approach to the study of the birdstrike phenomenon against several windshield geometries. A series of numerical simulations have been performed using the explicit finite element solver code LS-Dyna, in order to estimate the windshield-surround structure capability to absorb the bird impact energy, safely and efficiently, according to EASA Certification Specifications 25.631 (2011). The research considers the results obtained about a parametric numerical analysis of a simplified, but realistic, square flat windshield model, as reported in the last work (Grimaldi et al. 2013), where this model was subjected to the impact of a 1.8 kg bird model at 155 m/s to estimate the sensitivity of the target geometry, the impact angle, and the plate curvature on the impact response of the windshield structure. Then on the basis of these results in this paper the topic is focused about the development of a numerical simulation on a complete aircraft windshield-surround model with an innovative configuration. Both simulations have used a FE-SPH coupled approach for the fluid-structure interaction. The main achievement of this research has been the collection of analysis and results obtained on both simplified realistic and complete model analysis, addressed to approach with gained confidence the birdstrike problem. Guidelines for setting up a certification test, together with a design proposal for a test article are an important result of such simulations.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.26 no.3
• /
• pp.43-55
• /
• 2023

The railway project is an essential green transportation tool that is considered suitable for the domestic and foreign policy direction of carbon neutrality, but there are some limitations, such as damaging important carbon absorption sources during construction. This study analyzed the environmental impact assessment related to carbon absorption sources of greenhouse gas evaluation items conducted during the railway project, and limitations and implications were derived. The analysis of environmental impact assessment guidelines related to railway projects and carbon absorption sources dealt with prediction and reduction methods related to carbon absorption sources, but guidelines, including environmentally friendly railway construction guidelines, lacked descriptions. Since the greenhouse gas environmental impact assessment, 83 railway project environmental impact assessments have been reviewed, but in some cases, carbon absorption-related predictions have not been implemented, or carbon absorption-related reduction measures have been insufficient. In addition, there were cases where there was a limit to calculating emissions and reduction or where the reduction value was insignificant compared to emissions. In order to supplement the environmental impact assessment in the field of carbon absorption sources related to railway construction projects, alternatives such as quantitative emission and low reduction calculation, review of the no net loss system using the total environmental resource system, and linkage with climate change impact assessment are needed.

• Asian Journal of Atmospheric Environment
• /
• v.5 no.4
• /
• pp.205-215
• /
• 2011

Ozone ($O_3$) is a main component of photochemical oxidants and a phytotoxic air pollutant. Although the current levels of tropospheric $O_3$ in East Asia could adversely affect productivity of forest tree species, risk assessments of $O_3$ impact were limited. In this paper, we summarize the methodology of risk assessment of $O_3$ on forest tree species based on our two previous studies, risk assessments of $O_3$ impact on the growth of Fagus crenata by Watanabe et al. (2012) and on the annual carbon absorption of three representative conifers, Cryptomeria japonica, Pinus densiflora and Larix kaempferi by Watanabe et al. (2010). $O_3$ sensitivity of each tree species obtained from an experimental study, $O_3$ exposure and atmospheric N deposition based on field monitoring and vegetation survey were integrated by geographic information system method. Based on the results, we conclude that the area with high risk of $O_3$ impact does not necessarily correspond to the area with high $O_3$ exposure. The varieties of tree habitat, tree sensitivity to $O_3$ and annual carbon absorption among the tree species, and N deposition-induced change in the $O_3$ sensitivity of F. crenata are raised as the factors of discordance between areas with high risk and those with high $O_3$ exposure. In the last part of this paper, we discuss the present uncertainty and perspectives of risk assessment for the future studies on the impact of $O_3$ on forest tree species in East Asia.

• Journal of the Korean Institute of Gas
• /
• v.2 no.4
• /
• pp.42-46
• /
• 1998

Miniaturized specimen technology Permits mechanical behavior to be determined using a minimum volume of material. The technology is useful in case of not collecting a large amount of materials from industrial equipments. Five kinds of accelerated degradation materials were prepared by isothermal aging heat treatment at $630^{\circ}C$. Three kinds of specimens were prepared for impact testing. In order to increase plastic constraint of subsize specimen, side-groove was introduced. Results between subsize and full size impact testing were compared. Size effects correlations were developed for the impact properties of turbine rotor material. These correlations successfully predict the ductile brittle transition temperature (DBTT) of full size Charpy impact specimens based on subsize specimen data.

• Ecology and Resilient Infrastructure
• /
• v.4 no.4
• /
• pp.237-244
• /
• 2017

The Impact Mitigation Regulation was first introduced in Germany with an intention to avoid or reduce the natural ecology and landscape infringement as much as possible according to the development project. The system has is an advantage of being able to efficiently operate the linkage policy of land planning and environment planning to prevent the excessive development of the national land and to continue to manage it. This study applied the German natural impact mitigation system by revising and supplementing it according to the domestic situation with a biotope map of Juam-dong, Gwacheon City, as a case study area. Spatial analysis was conducted of biotope maps, landscape maps, and NDVI maps to suggest a plan to derive and preserve the areas excellent in an ecological and environmental value. It was confirmed the Impact Mitigation Regulation could be used as a policy link of the land-environment policy that minimizes the degree of the damage that cannot help occurring necessarily in the development of the national land and to manage that damage from the planning stage.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.8
• /
• pp.681-688
• /
• 2021

This paper considers the trajectory and impact point dispersion analysis of the test launch vehicle (TLV). The analysis, which performed before and after its flight test on November 28, 2018, is described and verified by comparing with the flight test results. The six degree-offreedom (DOF) simulation is used to compute the dispersion of the trajectory, attitude, and impact point, where the launch vehicle performance variations and wind effects during the atmospheric phase are included. The impact area to guarantee the flight safety is determined using the results of the dispersion analysis. The flight test results confirm that the safe flight of TLV is performed within the predicted dispersion boundary.