• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1858-1868
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• 2021

Resisting an accidental impact of large commercial aircrafts is an important aspect of advanced nuclear power plant (NPP) design. Especially after the 9·11 event, some regulations were enacted, which required the design of NPPs should consider the accidental impact of large commercial aircrafts. Normal working of equipment is important for stopping reactor under an impact when an NPP is in operation. However, there is a lack of reliable analysis and research on the impact test of nuclear prototype equipment. Therefore, in order to study the response of the equipment under high acceleration impact, a centrifugal pump is selected as the research object to perform the impact test. A horizontal half-sinusoidal pulse wave was applied to the working pump. The test results show that the horizontal response of the motor and flange is greater compared to other parts, as well as the vertical response of the coupling. The stress response of the pump body support and motor support is high, hence these parts should be considered in the design of the pump. Finally, combined with the damage and stress evaluation results of the pump under different amplitudes, the ultimate impact acceleration that the pump can withstand is given.

• Journal of Internet Computing and Services
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• v.22 no.1
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• pp.79-88
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• 2021

As drone industry increase with the advent of the 4th industrial revolution, yet ensured the safety of a drone crashing and incurring accidents which may result in significant damage to human life and assets. Thus, the authentication of drone safety is very urgent. For this reason, many countries are in need of institutional improvement in the aspect of authentication/legal systems by considering the importance of safety for drone. In this study, the regulations, research, and standards concerning drone safety are compared and analyzed. The analysis results can be used for improving the regulations of drone safety and standardization. The study can be contributed to invigorate drone industry by ensuring drone safety.

• Earthquakes and Structures
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• v.19 no.6
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• pp.485-498
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• 2020

Non-ductile detailing of Reinforced Concrete (RC) frames may lead to structural failure when the structure is subjected to earthquake response. These designs are generally encountered in older RC frames constructed prior to the introduction of the ductility aspect. The failure observed in the beam-column joints (BCJs) and accompanied by excessive column damage. This work examines the seismic performance and failure mode of non-ductile designed RC columns and exterior BCJs. The design was based on the actual building in Tainan City, Taiwan, that collapsed due to the 2016 Meinong earthquake. Hence, an experimental investigation using cyclic testing was performed on two columns and two BCJ specimens scaled down to 50%. The experiment resulted in a poor response in both specimens. Excessive cracks and their propagation due to the incursion of the lateral loads could be observed close to the top and bottom of the specimens. Joint shear failure appeared in the joints. The ductility of the member was below the desired value of 4. This is the minimum number required to survive an earthquake with a similar magnitude to that of El Centro. The evidence provides an understanding of the seismic failure of poorly detailed RC frame structures.

• Journal of the Korean Orthopaedic Association
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• v.56 no.4
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• pp.341-345
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• 2021

The infrapatellar fat pad (IPFP) is one of three fat pads located about the anterior knee. Injury in this region is relatively common. Damage to the IPFP is caused mostly by an iatrogenic injury from a surgical procedure or repeated small collision trauma. The authors experienced a case of an IPFP injury, that has not been reported in the domestic or international literature. In this case, acute IPFP separation followed by a contusion at the anterior aspect of knee in the kneeling position, confirmed using magnetic resonance imaging. The patient was fully recovered with conservative treatment.

• Steel and Composite Structures
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• v.47 no.3
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• pp.315-337
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• 2023

The steel structure is an assembly of individual structural members joined together by connections. The connections are the focal point to transfer the forces which is susceptible to damage easily. It is challenging to replace the affected connection parts after an earthquake. Hence, steel plates are utilised as a structural fuse that absorbs connection forces and fails first. The objective of the present research is to develop a beam-column end plate connection with single and dual fuse and study the effect of single fuse, dual fuse and combined action of fuse and damper. In this research, seismic resilient beam-column end plate connection is developed in the form of structural fuse. The novel connection consists of one main fuse was placed horizontally and secondary fuse was placed vertically over main fuse. The specimens are fabricated with the variation in number of fuse (single and dual) and position of fuse (beam flange top and bottom). From the fabricated ten specimens five specimens were loaded monotonically and five cyclically. The experimental results are compared with Finite Element Analysis results of Arunkumar and Umamaheswari (2022). The results are critically assessed in the aspect of moment-rotation behaviour, strain in connection components, connection stiffness, energy dissipation characteristics and ductility. While comparing the performance of total five specimens, the connection with fuse exhibited superior performance than the conventional connection. An equation is proposed for the moment of resistance of end-plate connection without and with structural fuse.

• Earthquakes and Structures
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• v.25 no.4
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• pp.269-282
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• 2023

This study investigates a rocking seismic isolation (RSI) system as a seismic protection measure against narrow-band ground-motions generated by earthquakes. Structures supported over RSIs are considered capable of reducing the lateral demands and damage of the main structural system through lifting and rocking. This lifting and rocking during earthquake activity is provided by free-standing columns. A single-degree-of-freedom (SDOF) system supported on a RSI system is subjected to narrow-band seismic motions and its response is compared to an analog system without RSI. The comparison is then extended to reinforced concrete linear frames with and without RSI; three-bay frames with 11 and 17 storeys are considered. It is found that the RSI systems significantly reduce acceleration and displacement demands in the main structural frames, more noticeably if the first structural mode dominates the response and for ratios of the predominant frequency of the ground motion to the predominant frequency of the main frame near one. It is also found that the RSI system is more effective in reducing lateral accelerations and displacements of the main structure when the aspect ratio, b/h, and size, R, of the free-standing columns decrease, although the rocking stability of the RSI system is also reduced.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.50 no.2
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• pp.110-115
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• 2024

A 22-year-old male patient presented to the clinic with severe pain in the preauricular area with an inability to completely occlude the jaw. Facial computed tomography and magnetic resonance imaging revealed a well-defined lesion that was tentatively diagnosed as a benign tumor or cystic mass. Surgical approach of a lesion in the condyle is delicate and problematic as many vulnerable anatomical structures are present. There are several methods for surgery in this area. Typically, an extraoral approach is dangerous because of potential injuries to nerves and arteries. The intraoral approach also presents difficulties due to the lack of visibility and accessibility. On occasion, coronoidectomy may be performed. The goal here was to determine an easier and safer new surgical approach to the condyle. We reached the anterior part of the pterygoid plate in the same method as in Le Fort I surgery. From this point, through the external pterygoid muscle, approaching the anterior aspect of the condyle is relatively easy and safe, with minimal damage to the surrounding tissues. Pus was drained at the site, and the lesion was diagnosed as an abscess. Pain and inability to close the mouth resolved without recurrence.

• Advances in nano research
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• v.16 no.1
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• pp.91-109
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• 2024

Carbon nanotubes are drawing wide attention of research communities and several industries due to their versatile capabilities covering mechanical and other multi-physical properties. However, owing to extreme operating conditions of the synthesis process of these nanostructures, they are often imposed with certain inevitable structural deformities such as single vacancy and nanopore defects. These random irregularities limit the intended functionalities of carbon nanotubes severely. In this article, we investigate the mechanical behaviour of double-wall carbon nanotubes (DWCNT) under the influence of arbitrarily distributed single vacancy and nanopore defects in the outer wall, inner wall, and both the walls. Large-scale molecular simulations reveal that the nanopore defects have more detrimental effects on the mechanical behaviour of DWCNTs, while the defects in the inner wall of DWCNTs make the nanostructures more vulnerable to withstand high longitudinal deformation. From a different perspective, to exploit the mechanics of damage for achieving defect-induced shape modulation and region-wise deformation control, we have further explored the localized longitudinal and transverse spatial effects of DWCNT by designing the defects for their regional distribution. The comprehensive numerical results of the present study would lead to the characterization of the critical mechanical properties of DWCNTs under the presence of inevitable intrinsic defects along with the aspect of defect-induced spatial modulation of shapes for prospective applications in a range of nanoelectromechanical systems and devices.

• Journal of Forest and Environmental Science
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• v.40 no.1
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• pp.24-34
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• 2024

Fire, being primarily a natural phenomenon, is impossible to control, although it is feasible to map the forest fire risk zone, minimizing the frequency of fires. The spread of a fire starting in any stand in a forest can be predicted, given the burning conditions. The natural cover of the land and the safety of the population may be threatened by the spread of forest fires; thus, the prevention of fire damage requires early discovery. Satellite data and geographic information system (GIS) can be used effectively to combine different forest-fire-causing factors for mapping the forest fire risk zone. This study mainly focuses on mapping forest fire risk in the Madikhola watershed. The primary causes of forest fires appear to be human negligence, uncontrolled fire in nearby forests and agricultural regions, and fire for pastoral purposes which were used to evaluate and assign risk values to the mapping process. The majority of fires, according to MODIS events, occurred from December to April, with March recording the highest occurrences. The Risk Zonation Map, which was prepared using LULC, Forest Type, Slope, Aspect, Elevation, Road Proximity, and Proximity to Water Bodies, showed that a High Fire Risk Zone comprised 29% of the Total Watershed Area, followed by a Moderate Risk Zone, covering 37% of the total area. The derived map products are helpful to local forest managers to minimize fire risks within the forests and take proper responses when fires break out. This study further recommends including the fuel factor and other fire-contributing factors to derive a higher resolution of the fire risk map.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.5
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• pp.20-30
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• 2003

This study is aimed at establishing the categories and items for ecological assessment and evaluation of the environmental friendliness of golf courses in the capital region of Korea. The categories and items for the assessment have been derived based on the existing literature and interviews with golf experts. This study covers 32 golf courses in the capital region of Korea that are available in terms of data and on-site surveys. In order to conduct a comprehensive assessment of the environmental friendliness of the golf courses, the assessment area was divided into 4 categories that include a total of 14 sub-categories. The 4 categories encompass 1) location, 2) topography, 3) vegetation, and 4) construction. As its sub-categories, the location category includes current land use and zoning in the National Land Use Management Law. Topography has 2 sub-categories in the damage ratio of existing topography, gradient, cut area, and slope height. The assessment of vegetation is largely based on site surveys in the categories of preservation of the existing vegetation, the use of natural resources and existing trees, the component ratio of native tree species, the multi-layered structure of vegetation, and the utilization of water purification plants. In the aspect of construction, afforestation on tile slopes and the utilization of existing surface soil were evaluated. The examination of comparative analysis among the 10 items as a ratio measure showed that the scores were low in the sub-categories of current land we, the use of existing trees, and the multi-layered structure of vegetation. However, the rating results were satisfactory in the 2 sub-categories including cut area, and the utilization of native tree species. Those proved to be contributing factors in the ecological health of the golf courses. According to correlation analysis of the 10 items to the overall ecological rating of each golf course, the sizes of the 32 golf courses were mainly affected by the damage ratio of existing topography, gradient, preservation of vegetation and slope height. This study has the initiative to conduct an ecological assessment of golf courses in the country based on site surveys. The study results revealed that location factors such as current land use, damage ratio of topography and gradient and topographical factors were the main factors affecting the environmental friendliness of golf courses. This indicates indicating the significance of these factors in the future construction practices of golf courses. Furthermore, this study raises the need for follow-up studies to establish more detailed assessment criteria and to develop assessment techniques for areas such as slope afforestation and water purification plants that need a qualitative approach.