• Journal of the Korean Society of Safety
• /
• v.26 no.2
• /
• pp.70-76
• /
• 2011

Industrial accident frequency in small- and medium-sized ship-building plants is much higher than that of large-sized ones so that safety management activities should be different. In that sense, voluntary hazard assessment would be helpful for small- and medium-sized plants. However, conventional hazard assessment items and methods had some problems that discouraged voluntary participation of plants concerned. This study aimed to develop a new model for small- and medium-sized ship-building plants that can promote and encourage voluntary hazard assessment activities. For that purpose, ship-building process was assumed as a sequence of phases, and accident characteristics were compared with them. From that result, relative weights of accident factors including ship-building phases, accident types, occupational category, accident-induced objects, and hazardous items were determined with accident frequency data and with the help of expert groups. Therefore, for web-based integrative computer programming, a plain but accident data-dependent model was developed, with an additive function for related agencies that want to collect assessment results. It is expected that this model would help small- and medium-sized ship-building plants that wanted not only simple checklists but also effective assessment and management guidelines.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.10a
• /
• pp.455-458
• /
• 2008

Former times Information Technology generally has only depended on text or sound, while nowadays information is being moved through a variety of image media. Cell phone, TV and computer have been major elements of modem society as mediators using image signal. Therefore, image signal processing also has been treated importantly and done actively. The processing has been developed in many fields of digital image processing technologies as image data compression, recognition, restoration, etc. Noises are inevitably generated by using the signals during the processing, and typical types of the noise are Impulse(salt & pepper) and AWGN(Addiction White Gaussian Noise). To reduce the noise, various kinds of filters have been developed, and according to each noise, it is being used different filter each. However, the noise is not generated by one signal but by a complex. In this paper, I suggested an image filter to remove the complex noise, and compared with existing filters' methods for verification.

• Membrane Journal
• /
• v.27 no.5
• /
• pp.458-467
• /
• 2017

In this study, we prepared PVDF membranes via TIPS for water treatment applications. PVDF was used for its excellent chemical and mechanical properties. The effect of coagulation bath composition, temperature, and heat capacity on the overall membrane morphology was studied and observed using SEM. A mixture of DOP and DBP was used as the diluent, and silica was used as an additive. It was observed that as the heat capacity of the coagulation bath increased, the crystallization rate of PVDF decreased yielding larger pores. Also, as the heat capacity of the coagulation bath decreased, the crystallization rate of PVDF increased yielding smaller pores.

• KSBB Journal
• /
• v.25 no.1
• /
• pp.1-10
• /
• 2010

Biodiesel is a type of biofuel obtained from bioresources and able to use in diesel vehicles as an alternative/additive to petro diesel. In recent biodiesel research, there are three main issues which include high quality biodiesel, low cost feed stock and a highly efficient biodiesel production process. The sustainable production and use of biodiesel are attracting much attention in the renewable energy field. In this paper, we review some of the literatures related to environmental and economic evaluation for biodiesel production and analysis the issues including life cycle assessment (LCA), global warming potential (GWP), energy consumption, biodiesel production cost, production technologies and feedstock.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.5C
• /
• pp.171-185
• /
• 2011

Ready-mixed shotcrete that mixed with high quality aggregate and can improve construction quality is produced in a dry mortar plant and transported to construction sites. Because of using aggregate that produced in a special plant, Ready-mixed shotcrete has many advantages : good grain-size distribution, minimum stone powder, high quality and standardization material, etc. In this basic study different from the existing study that limited to additive and accelerator, the improvement of aggregate quality was tried to upgrade the shotcrete performance. The investigation about the construction conditions of shotcrete was performed and the result of an opinion poll was analyzed for a good grasp of the problems in domestic shotcrete quality. Pilot Plant Test was also performed to minimize the material segregation in plant manufacturing process. In additions, the field test was performed to find the optimum contents of synthetic fiber, appearing the same flexible toughness with that of steel fiber, and to find the optimum replacement ratio of blast furnace slag.

• Journal of Community Nutrition
• /
• v.4 no.3
• /
• pp.187-194
• /
• 2002

This study was investigated the effects of exercise and supplementation of L-carnitine and antioxidants on hepatic mitochondrial function, especially oxidative phosphorylation (OXPHOS). Isolated hepatic mitochondria from 4 rat groups were functionally tested by an analysis of respiration and the coupling of this process to ATP synthesis in the presence of ADP. Four groups were non-trained, non-supplemented group (NTNS), non-trained, supplemented group (NTS), long term-trained, non-supplemented group (LTNS) , and long term-trained, supplemented group (LTS). The trained rats run on a treadmill (grade 10°,20 m/min) for 60min/day for 8 weeks. The supplemented rats were treated with L-carnitine (0.5% diet), vitamin E(0.5mg/g BW), vitamin C (0.5mg/g BW) and melatonin (1 $\mu$ g/g BW) for 8 weeks. There were exercise effects on improving mitochondrial OXPHOS. Within non-supplemented groups, exercised rats resulted in a significant decrease in state 4 oxygen consumption, which increased the respiratory control (RC) ratio and ADP : O (P/O) ratio. There were supplementation effects on improving mitochondrial OXPHOS, too. Within non-exercised rats, supplemented rats resulted in a significant decrease in state 4 oxygon consumption. which increased the RC ratio and P/O ratio. There were additive effects of exercise and supplementation on OXPHOS. Within supplemented rats, exercise resulted in an increase in RC ratio. Significant effects of exercise-supplement interaction on improving OXPHOS were identified. It suggests that exercise and supplementation of L-carnitine and antioxidants might improve more efficiently the impaired OXPHOS efficiency in mitochondrial dysfunction that recognized as is an important cause of degenerative diseases. (J Community Nutrition 4(3) : 187∼194, 2002)

• Journal of the Korean Society of Radiology
• /
• v.2 no.4
• /
• pp.33-40
• /
• 2008

Images acquired by a digital X-ray imaging system are inherently degraded due to system degradation process and additive noise sources. The system degradation in image quality is typically described as the system response function characterized by the modulation transfer function (MTF) and the noise term described as the noise power spectrum (NPS). In this case, we can restore the blur image as close as possible to the original image by using modified filtering designed for digital imaging system, as we know more precisely about the MTF and the NPS. In this paper, by performing simulation, we tried to restore blurred images taken from a digital X-ray imaging system based upon conventional filtering techniques such as a direct-inverse filtering, limited-inverse filtering, or a Wiener filtering, and evaluated the characteristics of the image restoration.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.316-316
• /
• 2010

Thin films spin-coated from solvent solutions are characterized by solution parameters and spin-coating process. In this study, performance characteristics of polymer solar cells were investigated with changing solution parameters such as solvent and additives. The phase-separation between polymer and fullerene is needed to make the percolation pathway for better transportation of hole and electron in polymer solar cells. For this reason, cooperative effects of solvent mixtures adding additives with distinct solubility have been studied recently. In this study, chlorobezene, 1, 2-dichlorbenzene, and chloroform were used as solvent. 1, 8-diiodoctaned and 1, 8-octanedithiol were used as additives and were added into poly(3-hexylthiophene-2, 5-diyl)/[6, 6]-phenyl C61 butyric acid methyl ester (P3HT/PCBM) blends. Pre-patterned ITO glass was cleaned using ultrasonication in mixed solvent with ethyl alcohol, isopropyl alcohol and acetone. PEDOT:PSS was spin-coated on to the ITO substrate at 3000rpm and was baked at $120^{\circ}C$ for 10min on the hotplate. The prepared solution was spin-coated at 1000rpm and the spin-coated thin film was dried in the Petri dishes. Al electrode was deposited on the thin film by thermal evaporation. The devices were annealed at $120^{\circ}C$ for 30min. By adding 2.5 volume percent of additives into the chlorobenzene from that bulk heterojunction films consisting of P3HT/PCBM, the power efficiency (AM 1.5G conditions) was increased from 2.16% to 2.69% and 3.12% respectively. We have investigated the effect of additives in P3HT/PCBM blends and the film characteristics and the film characteristics including J-V characteristics, absorption, photoluminescence, X-ray diffraction, and atomic force microscopy to mainly depict the morphology control by doping additives.

• International Journal of Highway Engineering
• /
• v.8 no.3 s.29
• /
• pp.163-172
• /
• 2006

This study evaluated the laboratory properties of asphalt binder and mixture modified with SPC(Sulfur Polymer Cement), which consists of sulfur as a main ingredient that is an industrial by-product made from refining process of crude oil and carbon-black as an additive. Four levels of SPC modifier ratios(0, 10, 30, 50%) were evaluated in the laboratory. Superpave(Superior Performing Asphalt Pavements) system was used to determine the PG(Performance Grade) and evaluate the property of SPC modified binder at the different temperatures. IDT(Indirect Tensile Test) was performed to evaluate the resistance of fatigue and low-temperature cracking at $10^{\circ}C\;and\;-10^{\circ}C$. Wheel-tracking test was also performed to evaluate the rutting-resistance of SPC modified asphalt mixtures. Test results showed that the more SPC modifier ratios, the better rutting-resistance and the more potential of low-temperature cracking resistance. However, SPC modifier did not show the effect on the fatigue cracking resistance.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.25 no.2
• /
• pp.156-165
• /
• 2015

Objectives: The purpose of this study was to investigate the possible effects of a gasoline vapor recovery system on personal exposure levels of gasoline vapor constituents including benzene, toluene, ethyl benzene, xylene(BTEX), and methyl tert-butyl ether(MTBE) among gas station workers in a metropolitan area. Methods: Thirty-one gas station workers at ten gas stations in a metropolitan area were selected as subjects for this study. Test method PV2028 as recommended in the OSHA process was used for sampling and analysis. Results: The personal exposure levels of benzene, toluene, ethyl benzene, xylene, MTBE and gasoline vapor in the gas station workers were $0.0018{\pm}0.0069ppm$, $0.0077{\pm}0.0137ppm$, $0.0002{\pm}0.0008ppm$, $0.0016{\pm}0.0084ppm$, $0.2619{\pm}0.3340ppm$, and $1.4940{\pm}1.7984ppm$, respectively. After adjustment for refueling frequency and volume, personal exposure levelswere higher in the gas stations where gasoline vapor recovery systems(Stage II) were not installed, but the results were not statistically significant. Gasoline vapor concentrations showed a positive correlation to the level of MTBE, a gasoline additive. Conclusions: Vapor recovery systems(Stage II) were effective not only in reducing emissions of air pollutants, but also in reducing exposure to hazardous substances among gas station workers. In addition, acorrelation between gasoline vapors and MTBE concentration was confirmed.