• Journal of Microbiology
• /
• 제40권4호
• /
• pp.340-343
• /
• 2002

A PCB degrader, Ralstonia eutropha H850 was shown to induce bphC gene encoding 2,3-dihydroxy-biphenyl-1,2-dioxygenase in a carvone-amended pure culture in our previous study (Park et al.,1999). The present study was carried out to examine how plant terpenes, as natural substrates, would cause an expression of a PCB degradative gene in soil that was amended with terpenes. The population of Ralstonia eutropha H850 was maintained at least around 10$\^$8/ (CFU/g fresh soil) in the soil amended with carvone or limonene in the presence of succinate as a growth substrate at 50 th day. The gene expression was monitored by RT-PCR using total RNA directly extracted from each soil and bphC gene primers. The bphC gene expression of the seeded strain H850 was observed in the soil amended with biphenyl (4 days) but not with succinate, carvone and limonene. These results indicate that terpenes widely distributed in nature could be a potential inducing substrate for effective PCB biodegration in the soil but their bioavailability and specific induction behavior should be taken into account before PCB bioremediation implementation.

• 한국보건간호학회지
• /
• 제28권1호
• /
• pp.5-21
• /
• 2014

Purpose: The purpose of this study was to examine perceived needs for exercise programs among adults in the workforce based on sociodemographic characteristics and health-related behaviors. Methods: The sample consisted of 182 office workers, sales workers, and service workers recruited at a worksite in Seoul (97 males and 85 females, Mean age=34.6, SD=7.71). Study participants completed a structured questionnaire on health-related behaviors and areas of needs for exercise programs. Analysis of data was performed using descriptive statistics and chi-square tests. Results: Workers with greater interest in exercise reported to engage in exercise. Significant differences were observed in goals of exercise, preferred exercise, preferred methods for delivery of exercise, preferred exercise monitoring, and social support for exercise maintenance according to age, sex, marital status, education, commuting time, occupation, alcohol use, smoking, and current participation in exercise. There were no differences in areas of exercise program needs by consumption of high calorie foods. Conclusion: Public health nurses can use these findings for development and implementation of tailored exercise programs to promote health for workers whose physical activity is insufficient.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 하계학술대회 논문집 A
• /
• pp.595-602
• /
• 1994

PERISTOR-3000 loaded with 32 bit DSP(Digital Signal Processor) is a technically advanced versatile dc motor controller in applications with very high requirements for rapid response, control accuracy and reliability. The current controller of PERISTOR-3000 is of the predictive type and gives fast control with both discontinuous and continuous current compared to the conventional PI current control. The speed controller gain is compensated to improve response behavior. PERISTOR-3000 communicates with its host computer, POSTAR-3200, or any IBM or compatible PC and can be controlled. Dedicated monitoring system for MMI is introduced.

• 한국대기환경학회지
• /
• 제19권2호
• /
• pp.179-189
• /
• 2003

The concentration of gaseous elemental mercury (Hg) was measured concurrently with relevant environmental parameters from Yang-Jae monitoring station in Seoul during Sept. 1997 to June 2002. Although data collection was disrupted for certain periods, the grand mean concentration of Hg for this five year period was found at 5.32 $\pm$ 3.53 ng m$^{-3}$ (N = 27,170). Because of short resolution of data acquisition, we were able to examine the temporal variability of Hg at varying time scale. The diurnal variability of Hg, when investigated for each of those five years, indicated consistently the dominance of nighttime over daytime. If examined at seasonal scale, Hg level was systematically higher during winter/spring than summer/fall period. The results of this short-term variability were best explained by the combined effects of such factors as meteorological conditions (formation of inversion layer and seasonal changes) and anthropogenic source processes. However, examination of long-term variation Pattern was much more complicated to explain. Thus, extension of our study is needed to diagnose the future direction in long-term trend of Hg behavior.

• Composites Research
• /
• 제14권6호
• /
• pp.24-31
• /
• 2001

필라멘트 와인딩 연소관의 제작에 있어서 라이너 표면의 형상과 와인딩되는 섬유각도는 제작 공정상의 편의와 제작 후 구조물의 성능에 큰 영향을 미친다. 본 연구에서는 두 개의 반구를 합친 험상의 라이너 위에 와인딩된 로켓 연소관의 유한 요소 해석을 수행하였다. 32개의 스트레인 게이지를 표면에 부탁한 후 수압실험을 실시하여 유만 요소 해석 과정을 검증하였고, 웨이퍼(wafer)를 통한 국부적 보강 방법에 대한 해석을 수행하였다. 파손에 따른 재료의 비선형 거동을 고려한 점진적 파손 해석을 통해 연소관의 과열 압력과 취약부위에 대한 연구를 수행하였다.

• 한국대기환경학회지
• /
• 제9권3호
• /
• pp.207-215
• /
• 1993

In order to statistically predict $O_3$ levels in Seoul, the study used the TMS (telemeted air monitoring system) data from the Department of Environment, which have monitored at 20 sites in 1989 and 1990. Each data in each site was characterized by 6 major criteria pollutants ($SO_2, TSP, CO, NO_2, THC, and O_3$) and 2 meteorological parameters, such as wind speed and wind direction. To select proper variables and to determine each pollutant's behavior, univariate statistical analyses were extensively studied in the beginning, and then various applied statistical techniques like cluster analysis, regression analysis, and expert system have been intensively examined. For the initial study of high level $O_3$ prediction, the raw data set in each site was separated into 2 group based on 60 ppb $O_3$ level. A hierarchical cluster analysis was applied to classify the group based on 60 ppb $O_3$ into small calsses. Each class in each site has its own pattern. Next, multiple regression for each class was repeatedly applied to determine an $O_3$ prediction submodel and to determine outliers in each class based on a certain level of standardized redisual. Thus, a prediction submodel for each homogeneous class could be obtained. The study was extended to model $O_3$ prediction for both on-time basis and 1-hr after basis. Finally, an expect system was used to build a unified classification rule based on examples of the homogenous classes for all of sites. Thus, a concept of high level $O_3$ prediction model was developed for one of $O_3$ alert systems.

• Asian Journal of Atmospheric Environment
• /
• 제4권3호
• /
• pp.166-176
• /
• 2010

In this research, the environmental behavior of carbon dioxide ($CO_2$) was investigated in a mountainous site in the proximity of a highly industrialized megacity, Seoul, Korea. The concentration data of $CO_2$ monitored routinely at hourly intervals at Mt. Gwan-Ak (GA), Seoul, Korea throughout 2009 were analyzed in several respects. The mean $CO_2$ value was $405{\pm}12.1$ ppm (median=403 ppm) with a range of 344 to 508 ppm (N=8548). The analysis of its seasonal trend indicated that the $CO_2$ levels peaked in the winter but reached a minimum in fall. If the short-term trend is analyzed, the $CO_2$ values generally peaked during daytime along with the presence of two shoulders; this is suspected to be indicative of strong man-made effects (e.g., traffic activities). It is seen that the general patterns of $CO_2$ distribution in this study area are highly comparable to those typically found in urban areas with strong signals of anthropogenic activities.

• Structural Monitoring and Maintenance
• /
• 제1권4호
• /
• pp.357-369
• /
• 2014

In the existing bridge management systems, assessment of the structural behavior is based on the results of visual inspections in which corresponding condition states are assigned to individual elements. In this process, limited attention is given to the correlation between bridge elements from structural perspective. Also, the uncertainty of parameters which affect the structural capacity is ignored. A system reliability-based assessment model is potentially an appropriate replacement for the existing procedures. The aim of this research is to evaluate the system reliability of existing conventional Steel-Reinforced bridge decks over time. The developed method utilizes the reliability theory and evaluates the structural safety for such bridges based on their failure mechanisms. System reliability analysis has been applied to simply-supported concrete bridge superstructures designed according to the Canadian Highway Bridge Design Code (CHBDC-S6) and the deterioration pattern is achieved based on the reliability estimates. Finally, the bridge condition index of an old existing bridge in Montreal has been estimated using the developed deterioration pattern. The results obtained from the developed reliability-based deterioration model and from the evaluation done by bridge engineers have been found to be in accordance.

• Structural Engineering and Mechanics
• /
• 제72권5호
• /
• pp.569-583
• /
• 2019

Tubular steel sections are widespread all over the world because of their strength and aesthetic appearance. Tubular steel members may exhibit local buckling such as elephant foot or overall buckling under extreme compression load. Recently, external bonding of fiber reinforced polymers (FRP) sheets for strengthening these members has been explored through experimental research. This paper presents three-dimensional nonlinear finite element analysis (FEA) to investigate the structural behavior of strengthening tubular steel members with FRP against local and overall buckling phenomena. Out-of-roundness and out-of-straightness imperfections were introduced to the numerical models to simulate the elephant foot and overall buckling, respectively. The nonlinear analysis preferences such as the integration scheme of the shell elements, the algorithm for solution of nonlinear equations, the loading procedure, the bisection limits for the load increments, and the convergence criteria were set, appropriately enough, to successfully track the sophisticated buckling deformations. The agreement between the results of both the presented FEA and the experimental research was evident. The FEA results demonstrated the power of the presented rigorous FEA in monitoring the plastic strain distribution and the buckling phenomena (initiation and propagation). Consequently, the buckling process was interpreted for each mode (elephant foot and overall) into three sequential stages. Furthermore, the influence of FRP layers on the nonlinear analysis preferences and the results was presented.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1996년도 춘계학술발표회논문집(3)
• /
• pp.145-150
• /
• 1996

Acoustic Emission (AE) technique was applied to stress corrosion cracking of Inconel 600 to investigate the AE capability of detecting crack growth and to obtain the relation between AE characteristics and crack mechanism. The specimens were heat-treated in two conditions (600$^{\circ}C$ for 30 hrs or 700 $^{\circ}C$ for 1 hr) and undergone CERT at two extension rates ( 2.5${\times}$10$^{-5}$ or 1.25${\times}$10$^{－4}$(mm/s)). It was found that the AE peak amplitude from plastic deformation was generally smaller than about 48dB (0.25mV), while Intergranular stress corrosion cracking (IGSCC) and ductile fracture produced higher values of 49 to 70dB (0.3mV to 3mV). The slopes of cumulative amplitude distribution (b-values) were linearly dependent on IGSCC susceptibility and the higher the susceptibility, the smaller the b-value. The monitoring of combined AE parameters such as event rate, amplitude, count and energy can provide effective means to clearly identify the transition from crack initiation and small crack growth to rapid growth of dominant cracks.