• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.22 no.4
• /
• pp.293-300
• /
• 2012

Objectives: In chemical hazard communication, information receiver's perception is a important factor, but the study on the perception was few. Therefore, this study evaluated the perception of managers and workers group about chemical hazard communication by chemical hazard communication tools that were being used in fields. Methods: 91 managers and 238 workers were surveyed in two companies where use chemicals. All subjects were asked about the comprehensibility and perception for MSDS and GHS Pictograms being used in their workplaces through face-to-face interviews. Results: Most of the respondents knew MSDS, and more than half of the respondents had used MSDS once or more per year. The level of use to find the information on chemicals with MSDS was higher in the managers in comparison with workers. Also, the managers could understand and find the information on MSDS easier(p < 0.05). In the question asking the meaning of GHS Pictograms, the managers responded more correctly, as well(p < 0.05). 86.8% of the managers and 62.6% of the workers were conscious of the possible health hazards of chemicals that they could be exposed at work. However, among the respondents conscious of the health hazards, only less than 70% were well aware of the contents of the health hazards correctly. Conclusions: In chemical hazard communication, it is very important to evaluate whether information receiver have proper and correct knowledge and perception or not and actions based on the evaluations as well as provide correct information.

• Geomechanics and Engineering
• /
• v.6 no.3
• /
• pp.293-320
• /
• 2014

In this study, in order to evaluate adequacy of considering local site effect, excluding soil-structure interaction (SSI) effects in inelastic dynamic analysis and design of mid-rise moment resisting building frames, three structural models including 5, 10, and 15 storey buildings are simulated in conjunction with two soil types with the shear wave velocities less than 600 m/s, representing soil classes $D_e$ and $E_e$ according to the classification of AS1170.4-2007 (Earthquake actions in Australia) having 30 m bedrock depth. Structural sections of the selected frames were designed according to AS3600:2009 (Australian Standard for Concrete Structures) after undertaking inelastic dynamic analysis under the influence of four different earthquake ground motions. Then the above mentioned frames were analysed under three different boundary conditions: (i) fixed base under direct influence of earthquake records; (ii) fixed base considering local site effect modifying the earthquake record only; and (iii) flexible-base (considering full soil-structure interaction). The results of the analyses in terms of base shears and structural drifts for the above mentioned boundary conditions are compared and discussed. It is concluded that the conventional inelastic design procedure by only including the local site effect excluding SSI cannot adequately guarantee the structural safety for mid-rise moment resisting buildings higher than 5 storeys resting on soft soil deposits.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2003.05a
• /
• pp.192-197
• /
• 2003

A virtual vessel traffic control system is introduced to contribute to prevent a marine accident, e.g. ship collision or stranding. from happening. The system that comes from VTS limitaions, consists of both data acquisition by satellite remote sensing and a simulation of traffic environment stress (here, INOUE model used) based on the satellite data. Remotely sensed data cab be used to provide timely and detailed information about the marine safety, including the location, speed and direction of ships, and help us operate vessels safely and efficiently. If in the future, e.g. 5-minute after, environmental stress values that a ship may encounter on a voyage can be available, proper actions can be taken to prevent accidents. It lastly can be shown that JERS satellite data are used to track ships and extract their information.

• Wind and Structures
• /
• v.29 no.5
• /
• pp.339-359
• /
• 2019

Pre-stressed concrete poles are among the supporting systems used to support transmission lines. It is essential to protect transmission line systems from harsh environmental attacks such as downburst wind events. Typically, these poles are designed to resist synoptic wind loading as current codes do not address high wind events in the form of downbursts. In the current study, the behavior of guyed pre-stressed concrete Transmission lines is studied under downburst loads. To the best of the authors' knowledge, this study is the first investigation to assess the behaviour of guyed pre-stressed concrete poles under downburst events. Due to the localized nature of those events, identifying the critical locations and parameters leading to peak forces on the poles is a challenging task. To overcome this challenge, an in-house built numerical model is developed incorporating the following: (1) a three-dimensional downburst wind field previously developed and validated using computational fluid dynamics simulations; (2) a computationally efficient analytical technique previously developed and validated to predict the non-linear behaviour of the conductors including the effects of the pretension force, sagging, insulator's stiffness and the non-uniform distribution of wind loads, and (3) a non-linear finite element model utilized to simulate the structural behaviour of the guyed pre-stressed concrete pole considering material nonlinearity. A parametric study is conducted by varying the downbursts locations relative to the guyed pole while considering three different span values. The results of this parametric study are utilized to identify critical downburst configurations leading to peak straining actions on the pole and the guys. This is followed by comparing the obtained critical load cases to new load cases proposed to ASCE-74 loading committee. A non-linear failure analysis is then conducted for the three considered guyed pre-stressed concrete transmission line systems to determine the downburst jet velocity at which the pole systems fail.

• Earthquakes and Structures
• /
• v.17 no.4
• /
• pp.373-385
• /
• 2019

In this article, different frequently adopted modeling aspects of linear and nonlinear dynamic soil-structure interaction (SSI) are studied on a pile-supported integral abutment bridge structure using the open-source platform OpenSees (McKenna et al. 2000, Mazzoni et al. 2007, McKenna and Fenves 2008) for a 2D domain. Analyzed approaches are as follows: (i) free field input at the base of fixed base bridge; (ii) SSI input at the base of fixed base bridge; (iii) SSI model with two dimensional quadrilateral soil elements interacting with bridge and incident input motion propagating upwards at model bottom boundary (with and without considering the effect of abutment backfill response); (iv) simplified SSI model by idealizing the interaction between structural and soil elements through nonlinear springs (with and without considering the effect of abutment backfill response). Salient conclusions of this paper include: (i) free-field motions may differ significantly from those computed at the base of the bridge foundations, thus put a significant bias on the inertial component of SSI; (ii) conventional modeling of SSI through series of soil springs and dashpot system seems to stay on the safer side under dynamic conditions when one considers the seismic actions on the structure by considering a fully coupled SSI model; (iii) consideration of abutment-backfill in the SSI model positively affects the general response of the bridge, as a result of large passive resistance that may develop behind the abutments.

• Structural Monitoring and Maintenance
• /
• v.2 no.3
• /
• pp.269-282
• /
• 2015

Civil structures should be designed with the lowest cost and longest lifetime possible and without service failure. The efficient and sustainable use of materials in building design and construction has always been at the forefront for civil engineers and environmentalists. Timber is one of the best contenders for these purposes particularly in terms of aesthetics; fire protection; strength-to-weight ratio; acoustic properties and seismic resistance. In recent years, timber has been used in commercial and taller buildings due to these significant advantages. It should be noted that, since the launch of the modern building standards and codes, a number of different structural systems have been developed to stabilise steel or concrete multistorey buildings, however, structural analysis of high-rise and multi-storey timber frame buildings subjected to lateral loads has not yet been fully understood. Additionally, timber degradation can occur as a result of biological decay of the elements and overloading that can result in structural damage. In such structures, the deficient members and joints require strengthening in order to satisfy new code requirements; determine acceptable level of safety; and avoid brittle failure following earthquake actions. This paper investigates performance assessment and damage assessment of older multi-storey timber buildings. One approach is to retrofit the beams in order to increase the ductility of the frame. Experimental studies indicate that Sprayed Fibre Reinforced Polymer (SFRP) repairing/retrofitting not only updates the integrity of the joint, but also increases its strength; stiffness; and ductility in such a way that the joint remains elastic. Non-linear finite element analysis ('pushover') is carried out to study the behaviour of the structure subjected to simulated gravity and lateral loads. A new global index is re-assessed for damage assessment of the plain and SFRP-retrofitted frames using capacity curves obtained from pushover analysis. This study shows that the proposed method is suitable for structural damage assessment of aged timber buildings. Also SFRP retrofitting can potentially improve the performance and load carrying capacity of the structure.

• Journal of Environmental Impact Assessment
• /
• v.24 no.4
• /
• pp.375-385
• /
• 2015

This study analyzed international case studies on Strategic Environmental Assessment (SEA) follow-up and suggested implications based on the study's findings to aid implementation of SEA follow-up in Korea. SEA requires follow-up in order to identify unforseen adverse effects and enable appropriate remedial action to be taken. Tool kits and methodological framework for effective SEA follow-up are only being researched recently. Based on the study's findings, following implications for implementing SEA follow-up in Korea were drawn. First, the system of carrying out SEA follow-up would be different depending on the PPP topic. During the scoping stage, significant impacts should be identified according to the PPP topic, and thus help determine the indicators to be developed in the later stage. Secondly, responsibility, method, time, intervals and actions from SEA follow-up may vary depending on the target SEA consultation. Thirdly, the indicators of SEA follow-up may be considered together with various environmental standards and current political, social and economic indicators which are a big issue in society. Fourthly, SEA follow-up can be used as an integration system of its target planning and environmental planning. Finally, SEA feedback system should be needed. The result of SEA follow-up should be used for target PPP. These would lead to improvements to the target PPP. If SEA follow up is successfully implemented and actively carried out for domestic PPPs, Korea can be a step closer to realization of sustainable development.

• Journal of Life Science
• /
• v.27 no.2
• /
• pp.247-266
• /
• 2017

Cordyceps is a traditional Chinese medicinal herb well-known in China, Korea and Japan since B.C. 2,000. The original entomopathogenic fungus, Cordyceps sinensis belonging to the genus Cordyceps could not be found inside Korean peninsula due to the absence of the host insect for the corresponding entomogenous fungus. The development of artificial production methods of Korean type Cordyceps using the silkworm Bombyx mori as in vivo culture medium for the the entomopathogenic fungus Paecilomyces tenuipes is the first, and wonderful occasion in the research history of insect industry of this global world. The aim of this article is to review the historical research background, mass-production methods, and pharmacological effects of the silkworm-dongchunghacho (Paecilomyces tenuipes) which is a newly developed Korean medicinal insect-borne mushroom, and another non-insect-borne medicinal mushroom (Cordyceps militaris and Cordyceps pruinosa). Their biological actions include anti-tumor, immunostimulating, anti-fatigue, anti-stress, anti-oxidant, anti-aging, anti-diabetic, anti-inflammatory, anti-thrombosis, hypolipidaemic and insecticidal effects. The bioactive principles are protein-bound polysaccharides (hexose, hexosamin), cordycepin, D-manitol, acidic polysaccharide etc. Protein-bound polysaccharides and n-butanol fractions were demonstrated to show a significant anti-tumor activities but did not show a cytotoxicities. D-mannitol exhibited a significant prolongation of the life span in tumor bearing mice. Ergosterol did not show an efficient anti-tumor activity, but showed a significant phagocytosis enhancing activity. Anti-tumor activity of silkworm-dongchunghacho might be attributed to immuno-stimulating activities rather than cytotoxic effects [164]. Also this review comprises the breeding of Dongchunghacho varieties, optimization of culture conditions, improvement of learning and memory by Dongchunghacho, application of them as foods and chemical constituents.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.3
• /
• pp.132-139
• /
• 2017

Endocrine disrupting chemicals (EDCs) interfere with endocrine system in organisms, and have different mode of actions compared to conventional chemicals. Therefore, EDCs specific ecotoxicity tests and assessments have been globally developed by some organizations such as OECD, ASTM, and USEPA. In Korea, researches on EDCs and monitoring of EDCs in domestic environments were also continued. However, Korean ecotoxicity test guidelines for EDCs are not suggested till date. The purpose of this study is to review and analyze international ecotoxicity test guidelines for EDCs and the compare ecotoxicity methods and toxicity endpoints among standard test guidelines. We found that there are very limited EDCs specific soil ecotoxicity test guidelines (only in ASTM) compared to aquatic ecotoxicity test guidelines. Currently, fish, amphibian, waterflea, copepoda, earthworm, white worm, springtail, nematode, mite, and midge are suggested as standard ecotoxicity test species for EDCs. Reproduction, hormones, growth, vitellogenin, sex retio and development were proposed as endpoints for EDCs ecotoxicity. This study provided the comparison of EDCs specific ecotoxicity methods and endpoints between standard test guidelines, and suggested the further research to develop the method for assesseing ecotoxicity of EDCs.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2003.10a
• /
• pp.170-170
• /
• 2003

An initial study has been conducted with Korea Institute of Geoscience and Mineral resources and National Institute of Environment Research to evaluate the distribution of radon levels and their risk levels of groundwater in Korea. Probability distribution of 616 samples was log-normal one with 1,867pCi/L as arithmetic value, 920pCi/L as median and 40,010pCi/L as maximum during iou. years(1999-2002). In addition, 10% of total samples are in excess of 4,000pCi/L, 20% in excess of 2,700pCi/L, and 30% in excess of 1,700pCi/L, and 15 samples exceeds 10,000pCi/L. Total samples are grouped into 10 areas and 5 rocks unit, and difference of concentrations among areas and rocks are statistically significant(respectively, p<0.0001). The highest area is Daejeon located in ogcheon metamorphic rocks and granitic rocks, and most of all sites with high concentration sites are located in granitic rocks. The lowest area is Jeju located in volcanic rocks. We have estimated excess cancer risks of radon based on these data. To estimate risks, first of all, use patterns of groundwater are categorized with 6 groups: for drinking, household, farming, washing cars, raising stock, and others. We considered risk only for drinking water and household water because radon is rapidly dispersed before it of other use reach human respiratory organs. We select 565 samples for risk analysis, and applied unit risk which is 6.6210-7 per pCi/L to be recommended by NAS committee. Unit risk was derived from considering radon ingestion and radon inhalation from water use. When estimating risk, we analyzed PDF of concentration and represented risk as 50 and 95 percentile values to consider uncertainty with Monte-Carlo simulation. It results in 10-4 level of their excess cancer risk and in 10-2 level in some areas with high concentration of radon. It must be monitor periodically and take adequate actions in these risky sites. We recommend that it needs to take more survey and finally set guideline for radon regulation in groundwater.