• Journal of Environmental Impact Assessment
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• v.14 no.2
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• pp.83-96
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• 2005

Brominated flame retardants have the market share of 40%, comparing others because of their low cost and highly effective retardation against the flame. However, their toxic effects in human and properties of the accumulation in the environments have been issued among the international organization such as EU, OECD and etc. It, therefore, was surveyed the classification, toxic effects, and the usage of Brominated flame retardants, the trends for their managements in the world and Korea, and their contaminated levels in Korean Peninsula. In addition, the management directions for them were proposed. Penta, octa, and deca-BDE among brominated retardants will seem to be prohibited by the regulation as a flame retardants for plastics in Europe because of their toxic effects. Although Penta and Octa BDEs was used marginally in Korea, deca-BDE was 27% of brominated flame retardants (49,050 ton) which had been used in 2002. However, risk assessment for brominated retardants might not launched in Korea, yet. These reports demonstrate that toxic brominated retardants such as PBDEs will be assessed for their usage and the level of contamination in the environment in the area of the point sources like the industrial areas, incinerators and etc. However, the law to regulate the hazardous chemicals seems not to be dictated the monitoring of their contamination in the environment. We, therefore, suggest how to evaluate and to monitor the toxic contaminants with EIA (Environmental Impact Assessment) and LCA (Life Cycle Assessment) system. Further, to establish the management system of BFRs (such as the monitering of contamination levels in environments, life cycle assessment, and risk assessment for the toxic chemicals), It can be recommended the law to deal with the method analyzing chemicals will be established, which contains QA/QC (Quality Assurance and Quality Control) to evaluate the analytic capability of the companies to prepare EIS (Environment Impact Statement) or other institutes for analyzing chemicals.

• Korea Journal of Hospital Management
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• v.7 no.1
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• pp.1-18
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• 2002

Empowerment is a multifaceted concept which can be described somewhat differently. In general, it is defined as the motivational concept of autonomy and self-efficacy. Recently, this concept of empowerment is applied to improve organizational staff's job satisfaction and organizational commitment in many organizations. Empowerment in service organizations has certainly generated more publicity than any other organizations. The objective of this study is to measure the degree of hospital administrative staff's empowerment using Spreitzer(1995)'s empowerment theory, and also to analyze the relationship of empowerment and job satisfaction and organizational commitment. Spreitzer argues that the work empowerment is composed of 4 dimensions (meaning, competence, self-determination, and impact) and each dimension influences employee's job satisfaction, organizational commitment, and organizational performance in the end. In order to carry out this study, data were collected by self-administered Questionnaires from 181 hospital administrative staff at 3 university hospitals in Inchon and Kyunggi-Do. The response rate is 86%. The Collected data were analyzed with SPSS statistical package V10.0. The major findings of this study are as follows: First, the degree of hospital administrative staff's empowerment is a high level point at the 7 Likert Scale. Second, the reliability of 3 variables, empowerment, job satisfaction and organizational commitment, was statistically satisfied(Cronbach's alpha>0.80). Third, as a result of correlation analysis, four components of empowerment, job satisfaction and organizational commitment showed a positive relationship. Finally, multiple regression analysis was conducted to find the impact of empowerment on job satisfaction and organizational commitment. In the case of job satisfaction, the meaning and competence factors have a positive effect(P<0.05). And the case of organizational commitment, the meaning and impact components have a positive relation(p<0.05). These results showed that the workplace empowerment is significantly related to employee's job satisfaction and organizational commitment.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.81-87
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• 2008

In this study, concerns the crashworthiness of the widely used vehicle structure, square thin-walled tubes, which are excellent on the point of the energy absorbing capacity. An experimental investigation was carried out to study the energy absorption characteristics of thin-walled square tubes subjected to dynamic crushing by axial loading to develop the optimum structural members. The impact velocity was tested in the rage $4.698{\sim}8.2m/s$. To efficiently review the collapse characteristics of these sections, the simulation have been carried out using explicit FEM package, LS-DYNA. The solutions compared with results the impact collapse experiment. Here, the controller are introduced to improve and control the absorbed energy of thin-walled square tubes in this paper. To predict and control the energy absorption, we designed it in consideration to the it's influence, height, thickness, wide ratio in this study. When the controller used, the experimental results of crushing of square tubes controlled by the controller's elements showed a good candidate for a controllable energy absorption capability in impact axial crushing.

• Journal of Environmental Impact Assessment
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• v.33 no.5
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• pp.228-251
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• 2024

It is clear that the implementation of Total Pollution Load Management (TPLM) has contributed to the improvement of river water quality in Korea. However, it is also true that the TPLM has focused on point source pollution management, with limitations in addressing non-point source pollution. This study examined the issues of the current TPLM from the perspective of non-point source pollution, which is closely related to high-flow conditions, by analyzing Load Duration Curves (LDC) using water quality and flow data collected over the past four years from 21 sub-watersheds in the Geum River Basin. Since the current TPLM is based on water quality predictions using a static water body model that applies the average flow of the dry season, we found that the reduction in loads required under actual flow conditions could be up to 140 times greater than under the reference flow condition, indicating that load amounts under high-flow conditions are not reflected. Additionally, there were abnormal correlations between discharge loads and water quality in several sub-watersheds, and illogical situations arose where compliance with allocated loads did not align with achieving the target water quality. While the causes of such abnormal and illogical situations are diverse and complex, this study highlights the need for rational reflection of non-point source loads under high-flow conditions in water quality modeling. As a solution, we propose the application of watershed models and dynamic water body models.

• Journal of Environmental Health Sciences
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• v.46 no.1
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• pp.88-95
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• 2020

Object: The purpose of this study was to select priority points for soil management using the location of groundwater and to suggest this method for soil contamination surveys. Method: Groundwater impact range was set to an area of 100 to 500 meters from the center point of agricultural groundwater wells. Data on industrial complex and factory areas, areas of stored or used ores and scrap metals, areas associated with waste and recycling, and traffic-related facilities areas were collected and checked for whether they fall within the groundwater impact range. Longitude and latitude coordinates of these data were mapped on the groundwater impact range using QGIS (Quantum Geographic Information System). Results: Considering the groundwater impact range, the points were selected as follows: 589 points were selected from 6,811 factories and 259 points were selected from 1,511 recycling business points. Traffic-related facility areas were divided between gas stations, bus depots, and auto mechanics. Thirty-four points were selected from 149 bus depots and 573 points were selected from 6,013 auto mechanic points. From the 2,409 gas station points, 323 were selected. Conclusion: Contaminated soil influences groundwater and crops, which can harm human health. However, soil pollution is not easily identified, so it is difficult to determine what has occurred. Pollution must be prevented beforehand and contaminated soil found. By selecting and investigating soil contamination survey points in consideration of the location of groundwater wells, we can safely manage water resources by preventing groundwater contamination in advance.

• Polymer(Korea)
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• v.25 no.3
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• pp.435-440
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• 2001

The objective of this study was to examine the effect of oxidation inhibitor contents on the work of adhesion, fracture toughness, and impact strength of the unidirectional carbon-carbon composites (C/C composites). The molybdenum disilicide ($MoSi_2$) used as an oxidation inhibitor was impregnated with phenolic resins to improve the anti-oxidation properties of the composites in different concentrations of 4, 12 and 20 wt%. Based on Wilhelmy equation, the work of adhesion of C/C composites was calculated by contact angle methods. Fracture toughness and impact strength were pressured by three-point bending test for the critical intensity factor ($K_IC$) and Izod test method, respectively. As a result, the composites made with $MoSi_2$ resulted in an increasing of both fracture toughness and impact strength. Especially, the composites made with 12 wt% $MoSi_2$ content showed the highest value of London dispersive component, $W_A\;^L$, in work of adhesion, resulting from improving the interfacial adhesion force among fibers, filler, and matrix in this system.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.639-648
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• 2013

Unconventional natural gas resources are now estimated to be as large as conventional resources. Unconventional natural gas has became an increasingly important source of energy in the world since the start of this century. The factors that drive natural gas demand and supply point more and more to a future in which natural gas plays greater role in the global energy mix. The expansion of using natural gas will be expected in Korea. This research aims to analyze environmental impacts of expansion of unconventional natural gas. This research was carried out for comparative analysis between global energy mix and Korea energy mix, and developed a case that reflect the changed energy mix due to the expansion of unconventional natural gas in Korea. Also this research evaluate the production of air pollutants and the cost of the damage in power generation sector. The results of this research can be summarized as that natural gas portion of future global energy mix (about 25%) is greater than Korea energy mix (about 12%). This research developed a case that replace 10% energy of power generation sector to natural gas in the 6th demand supply program, reflecting the changed energy mix due to the expansion of natural gas use. In that case, air pollutants would be reduced gradually through 2015 to 2027. In detail, carbon dioxide reduces 22 million tons and environmental damage cost reduces 4500 billion won by 2027.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.283-291
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• 2015

Objective : The purpose of this study was to determine the differences in the head and tibial acceleration signal magnitudes, and their powers and shock attenuations between flat-footed and normal-footed running. Methods : Ten flat-footed and ten normal-footed subjects ran barefoot on a treadmill with a force plate at 3.22m/s averaged from their preferred running speed using heel-toe running pattern while the head and tibial acceleration in the vertical axis data was collected. The accelerometers were sampled at 2000 Hz and voltage was set at 100 mv, respectively. The peak magnitudes of the head and tibial acceleration signals in time domain were calculated. The power spectral density(PSD) of each signal in the frequency domain was also calculated. In addition to that, shock attenuation was calculated by a transfer function of the head PSD relative to the tibia PSD. A one-way analysis of variance was used to determine the difference in time and frequency domain acceleration variables between the flat-footed and normal-footed groups running. Results : Peaks of the head and tibial acceleration signals were significantly greater during flat-footed group running than normal-footed group running(p<.05). PSDs of the tibial acceleration signal in the lower and higher frequency range were significantly greater during flat-footed running(p<.05), but PSDs of the head acceleration signal were not statistically different between the two groups. Flat-footed group running resulted in significantly greater shock attenuation for the higher frequency ranges compared with normal-footed group running(p<.05). Conclusion : The difference in impact shock magnitude and frequency content between flat-footed and normal-footed group during running suggested that the body had different ability to control impact shock from acceleration. It might be conjectured that flat-footed running was more vulnerable to potential injury than normal-footed running from an impact shock point of view.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.212-217
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• 2009

Strategic alliance is a proactive management process that integrates and optimizes value-added services of each party to best achieve business objectives of all parties within the relationship. Under the current competitive global environment, strategic alliance can produce a "Win-Win" situation and thus change paradigm that has resided in the construction industry. While many studies revealed the significance of alliance relationship in the industry, its impact on project performance has rarely been analyzed. Using the data obtained from 661 construction projects in the Construction Industry Institute database (359 projects from 38 owners and 302 projects from 29 contractors), this study first diagnoses the implementation status of strategic alliance at both project and company levels. Then, its impact on project performance is quantified and discussed. The descriptive analysis performed in this study revealed that an average of 79% of owner companies and 69% of contractor companies have ever implemented strategic alliance into at least one of their projects. However, both owner and contractor companies did not always use the strategy for all or their projects. Only 33% and 30% of projects reported by owners and contractors have been completed under alliance relationship, respectively. Analyzing the alliance impact on project performance, this study also establishes that strategic alliance positively affects project performance of both owners and contractors while owners should consider and control the level of its use for their projects. Recognizing and understanding the benefits from strategic alliance will be a starting point to produce mutual success among project participants, ultimately allowing the construction industry to go forward to a sustainable industry that transfers success from one project to the other.

• Korean Journal of Materials Research
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• v.34 no.7
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• pp.330-340
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• 2024

Al-Mg-Si alloys are light weight and have excellent corrosion resistance, and are attracting attention as a liner material for high-pressure hydrogen containers in hydrogen fuel cell vehicles. Because it has excellent plastic hardening properties, it is also applied to car body panel materials, but it is moderate in strength, so research to improve the strength by adding Si-rich or Cu is in progress. So far, the authors have conducted research on the intergranular fracture of alloys with excessive Si addition from the macroscopic mechanical point of view, such as specimen shape. To evaluate their impact tensile properties, the split-Hopkinson bar impact test was performed using thin plate specimens of coarse and fine grain alloys of Al-Mg-X (X = Cr,Si) alloy. The effect of the shape of the specimen on the characteristics was studied through finite element method (FEM) analysis. As a result, it was found that the intergranular fracture of the alloy with excessive Si depended on the specimen width (W)/grain size (d), which can be expressed by the specimen size and grain size. As W/d decreases, the intergranular fracture transforms into a transgranular fracture. As the strain rate increases, the fracture elongation decreases, and the fracture surface of the intergranular fracture becomes more brittle. It was confirmed that intergranular fracture occurred in the high strain rate region even in materials with small grain sizes.