• Journal of Korean Society for Atmospheric Environment
• /
• v.26 no.3
• /
• pp.305-317
• /
• 2010

In this research, a total of 11 newly designated offensive odorants in Korea in 2008 and 2010 (styrene (S), toluene (T), p-xylene (p-X), methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), butyl acetate (BuAc), isobutyl alcohol (i-BuAl), propionic acid (PA), butyric acid (BA), isovaleric acid (IA), and valeric acid (VA)) were selected as target compounds and analyzed from two types of gutter system in the urban environment. Because of the environmental significance of these compounds as offensive odorants, the results are meaningful enough to explore their behavior and distribution in the urban environmental systems. In the course of this study, samples were collected three times a day from two different gutter systems representing the wet (W) and dry (D) conditions. A large fraction of volatile organic compounds (VOCs) data fell into method detection limit (MDL) range with exceptions of toluene, p-xylene, and methyl ethyl ketone. In contrast, the results of organic fatty acids were distinguished by the relative dominance of butyric acid and propionic acid over others. If the concentration data of all odorants were converted into odor intensity (OI), the results of aromatics, ketones, acetate, and alcohol groups approached zero level. However, odor intensity of organic fatty acids was noticeably higher with the value of 2.8 (on average) from both W and D system, suggesting their potent roles as odorants in gutter system.

• Journal of Korean Foot and Ankle Society
• /
• v.22 no.3
• /
• pp.111-115
• /
• 2018

Purpose: Ingrown toenails are a common disease in the adolescent period and the treatments could be more conservative for this early stage of the disease. This study is a case series on the results of a gutter splint for an adolescent ingrown toe nail as a simple, comfortable treatment method. Materials and Methods: From 2011 to 2018, 22 patients (mean age, 12.2 years; range, 8~15 years) with ingrown toenails were treated with a gutter splint. There were 16 boys and 6 girls with 7 patients on both great toes, and additional 4 both corners of a nail, giving a total of 33 splints. Flat, plastic straws and glue or suture were used to protect the nail corners under local anesthesia. The medical records were reviewed retrospectively and phone calls were made to obtain the long-term results. Results: Fifteen splints were fixed with a suture and the other 18 splints were fixed with glue. There were 9 cases of recurrence out of 33 gutter splints, 8 out of 15 sutured splints and 1 out of 18 glued splints (p=0.010). There was no gender (p=0.383) or age (p=0.305) difference in the number of recurrences. Conclusion: For growing people, ingrown nails can be cured easily by conservative treatment for a transiently shortened or broken toenail. The glued gutter splint had a reasonable success rate as a first line treatment.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.05a
• /
• pp.319-322
• /
• 2003

For the analysis of leveling process by the 3-dimensional elastic-plastic finite element method, a finite element analysis program modeling large deformation of shell has been developed. This program fur analyzing large deformation of sheet during leveling includes spring-back analysis as well as efficient contact treatment between sheet and rolls of leveler. This is verified by the simple leveling experiment with 5 rolls at laboratory. Besides the leveling examples, problems within the category of large strain and rotation, such as 3-dimensional roll-up and gutter occurrence at continuous bending-unbending process are also tested for verification of the program. The residual curvatures of strip predicted by finite element analysis are within 20% error range of the experiment. The formation and direction of anticlastic curvature or gutter during bending-unbending under tension is predicted and this agrees with the experimental results.

• Transactions of Materials Processing
• /
• v.6 no.2
• /
• pp.118-135
• /
• 1997

In order to analyze the deformation and residual curvature of steel sheets in the strip processing lines, a program for calculating curvature and work hardening of sheet was developed. Strip deformation caused by repeated bending under tension in the process lines was analyzed on the basis of the incremental-plasticity theory with the mixed hardenting model for the purpose of predicting the strip shape and the yield stress change. The developed calculation program was applied to predict curl and gutter of sheets within a 10% difference. The yield stress increment was also predicted with the similar accuracy. Application of the model to tension legvelling process showed that gutter could be controlled by intermesh and elongation. The yield stress increment in the electro-galvanizing line calculated by the developed program was found to be dependent on the yield strength, the applied tension and the diameter of the smallest roll.

• 한국연소학회:학술대회논문집
• /
• 2012.11a
• /
• pp.351-354
• /
• 2012

The characteristics of flame dynamics occurring near bluff body was experimentally investigated in a model combustor with V-gutter bluff body. Flashback occurs due to the change of pressure gradient in the combustor, and flashback distance depends on equivalent ratio. Unstable flames can be classified into three types depending on the flashback distance and structure. Re-stabilization takes place as the flame moves downstream. This process is supported by a strong vortex structure behind bluff body.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.577-580
• /
• 2006

This paper presents the experimental results of frost durability characteristics including freezing-thawing and de-icing salt scaling of the concrete used for gutter of the road. Mixtures were proportioned with the three level of water-binder ratio (W/B), 0.58, 0.53, and 0.48, and two binder compositions corresponding to Type I cement without any supplementary cementitious materials (OPC) and Type I cement with 30% blast-furnace slag replacement (Slag30). Also, two different solutions of calcium chloride and water that contains 0 and 8g of anhydrous calcium chloride in each 100 mL of solution, respectively, were used to evaluate their effect on the frost durability resistance. Test results showed that the Slag30 mixture exhibited higher durability factor and lower mass loss values than those made with OPC. Among the mixture tested in this work, the mixtures (OPC and Slag30) made with a relatively higher W/B of 0.58 exhibited large amount of the de-icing salt scaling regardless of calcium chloride concentration. Finally, the use of slag can be used effectively in terms of economy and frost durability of the concrete designated for gutter.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.447-448
• /
• 2008

The goal of this study is to find flame dynamic behavior using a transverse fuel injection in a model combustor, and is to investigate main causes of unstable combustion in a liquid-fueled combustor. For transverse fuel injection into air cross flow, spray result shows similar tendency with Wu et al.[1998] until spray arrives at flame-holder. However, passing through flame-holder, fuel inflow into recirculation region of flameholder is not sufficient so it makes large difference between shear flame and recirculation flame behind flameholder. In combustion tests, the stable flame shows a kind of shear flames and low peaks of dynamic pressure frequencies. On the other hand, unstable flame shows periodic detached flame in recirculation zone and a strong peak of dynamic pressure frequency. The instability frequency is highly affected by influx air velocity, air temperature, equivalence ratio and wake or vortex shedding frequency behind the flameholder.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.10a
• /
• pp.255-258
• /
• 2003

In this study, to develop a flash-less die for forming of shoe-outsole, experiments and forming analysis were carried out. In order to reduce the extra-materials, of feet method and mass distribution method are used in the preform design. To improve the accuracy of contact surface of dies, the contact status of dies are measured by using the pressure film. The vertical pressing die structure and the guide-gutter system have been developed for the discharge of extra-materials and re-pressing. By the investigation, flash of shoe-outsole was considerably reduced.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.1
• /
• pp.103-108
• /
• 2005

In this study, to develop a flash-less mold for forming of shoe-outsole, experiments and forming analysis were carried out. In order to reduce the extra-materials, offset method and mass distribution method are used in the preform design. The vertical mold structure pressing the preform was introduced to produce a flash-less shoe-sole. To measure the contact status of parting surface of mold, the pressure film has been used. The guide-gutter system and the continuous pressing mold have been developed for the discharge of extra-materials and re-pressing. By the investigation, flash of shoe-outsole was considerably reduced.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.603-607
• /
• 2011

Structure of flashback and reignition occurring near flameholder was experimentally investigated in a model combustor with V-gutter flameholder. The combustor has a long duct shape with cross section of $40{\times}40mm$ and City Nature Gas(CNG) were used as fuel. Measurements of chemiluminescence with high speed camera was used for visualization of flame structure. In the lean case, flashback distance depend on equivalent ratio. New flame occurred at the front tip of flameholder when flashback. Flashback flame moved toward downstream direction of combustor because mixture flow velocity had increased, and then re-ignition was caused by entering flow into recirculation zone that is formed behind the flameholder.