• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.3085-3099
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• 2021

Investigations of large commercial aircraft impact effect on nuclear power plant (NPP) buildings have been drawing extensive attentions, particularly after the 9/11 event, and this paper aims to numerically assess the damage and vibrations of NPP buildings subjected to aircrafts crash. In Part I of present paper, two shots of reduce-scaled model test of aircraft impact on NPP were conducted based on the large rocket sled loading test platform. In the present part, the numerical simulations of both scaled and prototype aircraft impact on NPP buildings are further performed by adopting the commercial program LS-DYNA. Firstly, the refined finite element (FE) models of both scaled aircraft and NPP models in Part I are established, and the model impact test is numerically simulated. The validities of the adopted numerical algorithm, constitutive model and the corresponding parameters are verified based on the experimental NPP model damages and accelerations. Then, the refined simulations of prototype A380 aircraft impact on a hypothetical NPP building are further carried out. It indicates that the NPP building can totally withstand the impact of A380 at a velocity of 150 m/s, while the accompanied intensive vibrations may still lead to different levels of damage on the nuclear related equipment. Referring to the guideline NEI07-13, a maximum acceleration contour is plotted and the shock damage propagation distances under aircraft impact are assessed, which indicates that the nuclear equipment located within 11.5 m from the impact point may endure malfunction. Finally, by respectively considering the rigid and deformable impacts mainly induced by aircraft engine and fuselage, an improved Riera function is proposed to predict the impact force of aircraft A380.

• Journal of Environmental Impact Assessment
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• v.19 no.5
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• pp.453-464
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• 2010

We evaluated the status and problems of golf course developments in the southern coast of Korea. It's adjacent waters supports nursery and fishing grounds for commercially-important fisheries species, and various sites are designated and protected as marine protection area(MPA), fisheries reserve, or clean area(blue belt) for producing shellfish. We proposed key assessment items for environmental impact assessment(EIA) and checklists in selecting golf course locations. For the protected areas, we suggest that it is essential to limit golf course establishment while setting a minimal distance from the coast to secure a buffer zone for mitigating the environmental impacts. To efficiently utilize existing regional coastal management plans, it is necessary to diagnose how a golf course development will potentially modify geomorphology and scenery, amplify pollutant loads from non-point sources, and disrupt the functions of coastal ecosystem. Especially, continued monitoring and assesssing input loads of hazardous materials originating from agricultural chemicals should be obligatory. Finally, measures for improving the QA/QC analysis were discussed to enhance reliability of environmental data with respect to golf courses and adjacent coastal waters.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.7
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• pp.91-97
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• 2004

The first Korean liquid propellant rocket KSR-III successfully finished its flight test on Nov. 28, 2002. Herein, we summarize the results of range safety system operation which is employed for the first time in flight tests of rockets developed by Korea Aerospace Research Institute(KARI). During the flight, safety-critical flight data including instantaneous impact points are monitored in realtime by range safety officers utilizing Range Safety Display Systems. The recorded screen of the display system is presented for the explanation of safety operation. In addition, comparisons are made between onboard navigation system based and radar based results in calculating instantaneous impact points, and also errors from the finally recorded impact point are described.

• Journal of Korean Society of Transportation
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• v.18 no.4
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• pp.107-115
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• 2000

We suggest a method which solves the planar, two vehicle collision reconstruction problem. The method based on the Principle of impulse and momentum determines the pre-impact velocity components from Post-impact velocity components, vehicle Physical data and collision geometry. A novel feature is that although the impact coefficients such as the restitution coefficient and the impulse ratio are unknown, the method can estimate automatically the coefficients and calculate the pre-impact velocity components. This reverse calculation is important for vehicle accident reconstruction, since the pre-impact velocities are unknown and Post-impact Phase is the starting Point in a usual collision analysis. However. an inverse solution is not always Possible with the analytical rigid-body impact model. Mathematically, one does not exist under the common velocity condition. On the other hand, our method has a capability of reverse calculation under the condition if the absorbed energy during the collision process can be estimated using the crush profile. To validate the developed collision reconstruction a1gorithm, we use car-to-car collision test results. The analysis and experimental results agree well in the impact coefficients and the Pre-impact velocity components.

• Journal of Environmental Impact Assessment
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• v.27 no.1
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• pp.73-82
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• 2018

The purpose of this study is the evaluation of the impact of increase in impervious areas due to urbanization on the pollutant discharge using the HSPF model at Musim watershed. Model calibration and validation were performed based on the observed data 2015 and 2014, all simulation items have been successfully simulated such as flow, BOD, and TP. The land cover map used in the model reflected on the land use status of the Musim watershed in 2015 and the application of the development areas and locations. As a result of simulation, during rainfall daily pollutant load with the increased impervious land increased more than that before the development. However, the pollutant load decreased during the non-rainfall time. Annual pollutant load in rainfall time was significantly higher than that in non-rainfall time, BOD and TP increased. The simulation of non-point source pollutant load was applied under two assumptions, such as the increased area of impervious land and the non-change number of point source load before and after development. As the result of a simulation, the non-point source pollutant load after development was bigger than those before development. It was necessary to take measures to control non-point source pollution at the consideration status of development.

• Journal of Information Science Theory and Practice
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• v.11 no.3
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• pp.1-15
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• 2023

The present study examines the impact of value co-creation on satisfaction and intention to adopt of e-resources among users. Four components of the DART model have been adopted to describe value co-creation. These components are dialogue, access, risk-assessment, and transparency. Ph.D. scholars and faculty members from National Capital Region, India, were requested to respond on a five-point Likert scale. A total of 220 responses were collected with the help of a structured questionnaire from respondents of the top 50 business schools according to National Institute Ranking Framework. These responses have been analysed by means of structured equation modelling on Adanco 2.2 software. Findings of the study reported the insignificant impact of access and risk-assessment, and positive impact of dialogue and transparency on satisfaction. Further, satisfaction has been identified, creating significant impact on adoption of e-resources. Such findings reflect the real picture of customer experience with respect to their role in co-creation of e-resources. Respondents have conveyed their dissatisfaction with the co-creation process of e-resources, as companies do not provide all the information and access to their customers beforehand. Consequently, customers fail to make informed decisions and also find themselves unable to show trust in the service providers of e-resources.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.7
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• pp.2196-2204
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• 1996

The damage mechanism by the impact of steel ball on the soda-lime glass having a different surface roughness was investigated. An initiation and a propagation behavior of cracks formed by each impact velocity were quantitatively studied. A 4-point bending test was carried out to evaluate the remaining bending strength of a scratched soda-lime glass which impacted by the steel ball. As the surface roughness was increased, the shape of cracks became more irregular rather than those of the smooth specimens. The phenomenon of turning up in the wing of cone cracks occurred even at the lower velocity than the critical velocity caused the crushing. The threshold velocity of cracks initiation generally became lower than those of smooth specimen. An initiation and a propagation behavior of radial cracks had no relation with the direction of scratch on the surface. The remaning benidng strength of the scratched specimen according to impact velocity had no big difference compared with those of the smooth specimen.

• Journal of Welding and Joining
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• v.22 no.6
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• pp.57-63
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• 2004

Fracture toughness is an important parameter in designing offshore structures to ensure resistance to fracture at various temperatures. In this study, a series of experiments is carried out to obtain fracture toughness values (CTOD) of API 2W Gr.50B, welded using FCAW(Flux Cored Arc Weld). In particular, a comparison of absorbed impact energy and CTOD values are made with respect to two different welding groove shapes; double-V-groove and double-bevel-groove. Charpy impact tests are performed for specimens sampled near the root gap, and CTOD tests are carried out for three point bending specimens having the notch at weld zone. While Charpy impact test result is determined to be a good qualitative measure of fracture toughness, no quantitative correspondence between impact absorbed energy and CTOD values was found. Based on the experiment, it is observed that double-V-groove welds give lower transition temperature than those of double-bevel-groove.

• Journal of Environmental Impact Assessment
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• v.11 no.3
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• pp.205-221
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• 2002

Environmental impact assessment (EIA) is a tool used in planning development strategies and projects, and its use has been adopted into planning regulations in a number of countries. EIA has progressed from the consideration of pollution assessment, through the wider range of ecological assessment. Now EIA is required to consider the textbook of university students. Students taking lesson on EIA textbook are generally majoring in a variety of subjects, including environmental engineering, environmental health, environmental science, city planning, civil engineering, public policy, economics, and applied earth sciences. However, substantiality program of teaching material on EIA textbook has not been studied at expert society in the meantime, though a number of EIA textbook have been published every year in Korea. In current study, we presented the point at issue and improvement method of teaching material of EIA for student using domestic and foreign teaching materials and papers.

• Monthly Notices of the Royal Astronomical Society
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• v.496 no.4
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• pp.4787-4821
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• 2020

The merging rate of cosmic structures is computed, relying on the ansatz that they can be predicted in the initial linear density field from the coalescence of critical points with increasing smoothing scale, used here as a proxy for cosmic time. Beyond the mergers of peaks with saddle points (a proxy for halo mergers), we consider the coalescence and nucleation of all sets of critical points, including wall-saddle to filament-saddle and wall-saddle to minima (a proxy for filament and void mergers, respectively), as they impact the geometry of galactic infall, and in particular filament disconnection. Analytical predictions of the one-point statistics are validated against multiscale measurements in 2D and 3D realizations of Gaussian random fields (the corresponding code being available upon request) and compared qualitatively to cosmological N-body simulations at early times (z ≥ 10) and large scales (≥5 Mpc h^-1). The rate of filament coalescence is compared to the merger rate of haloes and the two-point clustering of these events is computed, along with their cross-correlations with critical points. These correlations are qualitatively consistent with the preservation of the connectivity of dark matter haloes, and the impact of the large-scale structures on assembly bias. The destruction rate of haloes and voids as a function of mass and redshift is quantified down to z = 0 for a Lambda cold dark matter cosmology. The one-point statistics in higher dimensions are also presented, together with consistency relations between critical point and critical event counts.