• Archives of Craniofacial Surgery
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• v.10 no.1
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• pp.1-6
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• 2009

Purpose: This study presents a classification of pure medial and inferior blow-out fracture, and confirms the relationship between the types of fractures, postoperative complications and operative methods. Methods: Sixty patients were treated by transnasal endoscopic reduction with $Medpor^{(R)}$ implantation through subciliary incision and foley catheter insertion into maxillary sinus was done if there was extensive orbital floor fracture. Fractures were classified by number of coronal sections from posterior margin of fossa for lacrimal sac to orbital apex in CT. Type I is defined when the medial wall fracture is over 50% and inferior wall fracture below 50%. Type II, when below 50% medial wall fracture and over 50% floor fracture were present. If there were both over 50%, it was classified as Type III and both below 50% for Type IV. Extreme fracture involving orbital buttress was Type V and postoperative findings in all patients were examined. Results: Type I and V were most common and preoperative findings were more likely to present according to extent of inferior fracture. Diplopia remained in 2 cases after additional insertion of foley catheter, but enophthalmos over 2 mm were presented in 3 cases and diplopia in 3 cases were observed who were not treated with foley catheter. Conclusion: Postoperative complications were increased according to extent of fracture, especially buttress involvement. Additional insertion of foley catheter proved its effectiveness in decreasing postoperative complications.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.7
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• pp.729-738
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• 2010

The characteristics of lifted butane flames diluted with nitrogen have been investigated experimentally in order to elucidate the mechanism of individual flame oscillation modes. Flame oscillations in laminar free-jet lift-off flames are classified into the following five regimes: a stabilized lift-off regime (I), a heat-loss-induced oscillation (II), a buoyancy-induced oscillation along with a heat-loss-induced oscillation (III), a combined form of an oscillation prior to blow-out and a heat-loss-induced oscillation (IV), and a combination of an oscillation prior to blow-out and a buoyancy-induced oscillation along with a heat-loss-induced oscillation (V). The characterization of the individual flame oscillations modes are presented and discussed using Strouhal numbers and their relevant parameters by the analysis of the power spectrum for temporal variation of the lift-off height.

• Archives of Plastic Surgery
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• v.41 no.4
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• pp.355-361
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• 2014

Background A blow-out fracture is one of the most common facial injuries in midface trauma. Orbital wall reconstruction is extremely important because it can cause various functional and aesthetic sequelae. Although many materials are available, there are no uniformly accepted guidelines regarding material selection for orbital wall reconstruction. Methods From January 2007 to August 2012, a total of 78 patients with blow-out fractures were analyzed. 36 patients received absorbable mesh plates, and 42 patients received titanium-dynamic mesh plates. Both groups were retrospectively evaluated for therapeutic efficacy and safety according to the incidence of three different complications: enophthalmos, extraocular movement impairment, and diplopia. Results For all groups (inferior wall fracture group, medial wall fractrue group, and combined inferomedial wall fracture group), there were improvements in the incidence of each complication regardless of implant types. Moreover, a significant improvement of enophthalmos occurred for both types of implants in group 1 (inferior wall fracture group). However, we found no statistically significant differences of efficacy or complication rate in every groups between both implant types. Conclusions Both types of implants showed good results without significant differences in long-term follow up, even though we expected the higher recurrent enophthalmos rate in patients with absorbable plate. In conclusion, both types seem to be equally effective and safe for orbital wall reconstruction. In particular, both implant types significantly improve the incidence of enophthalmos in cases of inferior orbital wall fractures.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.149-157
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• 2004

A Piston assembly is very important because it directly receives the energy generated during combustion process. Surely, the friction and lubrication of piston ring pack do an important role in the performance and fuel economy of an engine. in fact, the friction loss in piston ring pack is the biggest portion to the whole engine friction. Therefore, the improvement of lubrication quality and friction loss in piston ring pack will be directly related with the improvement in the performance and fuel economy of an engine. Meanwhile, the oil consumption and blow-by gas through piston-cylinder-ring crevices have to be controlled as less as possible. In these two aspects, the study on the optimized design of piston ring pack has to be carried out. In this study, for the efficient design of piston ring pack, it is focused to develop a basic computer program that predicts the inter-ring pressure, the motion of ring and the blow-by gas through a crevice volume model between adjacent rings, and the oil film thickness and the friction computed by lubrication theories.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.5
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• pp.1269-1279
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• 1995

An experimental study is carried out on turbulent diffusion flames stabilized by a circular cylinder in a divergent duct flow. A commercial grade gaseous propane is injected from two slits on the rod as fuel. Flame stability limits, as well as size and temperrature of recirculation zone, are measured by direct and schlieren photographs to clarify the characteristics and structure of diffusion flames and to assess the effect of various divergent angle of duct. The results of the present study are as follows. Temperature in the recirculation zone decreases with increasing divergent angle. The blow-off velocity in parallel duct is higher than that in divergent duct. Critical blow-off velocity is expected to be about 8-12 degree through blow-off velocity pattern. Regardless of divergent angles, the length of recirculation zone is nearly constant, and this length becomes longer with rod diameter. Pressure gradient has an effect on the eddy structure in shear layer behind the rod. With the increase of divergent angle, large scale eddies by dissipated energy in shear layer are split into small scale eddies, and the flame becomes a typical distributedreacting flame.

• Journal of Power System Engineering
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• v.21 no.4
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• pp.84-93
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• 2017

This study was carried out to improve the electric power consumption of HVAC in the blow mold machine(BMM) and work environment. The experiment was conducted with the simulated HVAC system of 1/15 of the actual BMM. The temperature of main facility and two preheaters was fixed at 200 and $60^{\circ}C$ respectively in all test conditions. The measured points of temperature were chosen as critical locations considering the work environment. The tendency of temperature distributions decreases as the duct was closed to the main facility. The reduction rate of power consumption of HVAC increases up to 32.3% when both duct and cooling systems are operated. Also the efficiency of HVAC is improved about 9% through the modified design of duct system. It notes that the electric power consumption of HVAC can be reduced by the optimum design and operating condition of duct and cooling system.

• Journal of Animal Environmental Science
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• v.5 no.3
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• pp.181-188
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• 1999

This study was carried out to investigate the effect of blowing fan for reducing heat stress in lactating dairy cows in summer. Treatment conditions were divided into 3 types ; No blow(T1), blow to oblique angle(T2) and blow to right angle(T3). Feed intake milk yield, respiration rate, rectal temperature and plasma cortisol concenration were measured to investigate the effect of hot environment on the physiological, productive responses in lactating dairy cows. The results obtained are summarized as follows: The daily milk yields were 20.47, 22.82 and 24.31kg per head in T1, T2 and T3 during experimental period, respectively. The respiration rate was significantly (p<0.05) higher in T1 than those of T2 and T3. The rectal temperature in T1(39.4$^{\circ}C$) was higher than those of T2(39.1$^{\circ}C$), (P<0.05). The plasma cortisol concentration was higher in T1 than those of T2 and T3(P<0.05). It was suggested that blowing fan installed in the pen was effective means to reduce heat stress.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1571-1578
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• 2015

The cleaning characteristics of pulse air jet type cleaning system which is widely applied in the industries were identified by utilizing the computational fluid dynamics (CFD) and the cleaning performance in modified shape of dedusting unit was compared in this study. The review on each shape of cleaning part showed that the case of installing the nozzle on the blow tube (Case-3) and the case of installing the double intaking tube to the venturi (Case-4 and Case-5) were more excellent than the structure (Case-1). Also, the optimal venturi shape was designed and examined its applicability to the site in a pilot scale plant. A combined system of a blow tube and a venturi proposed by this study turned out to be very effective for concentrating an cleaning air compared to existing systems, such as using only blow tube and combines the blow tube and venturi. In addition, as a result of installing and testing a venturi proposed by this study, the cleaning frequency and cleaning time were much improved compared to a case of using a commercial venturi that is under use at the industrial sites.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.73-78
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• 2006

The lifted oscillating flame has been studied using experiments of inverse diffusion flames that the air jet injected into a methane background. To find out the characteristics of inverse diffusion flames, fundamentally flame stabilized diagram is investigated with various air and fuel jet velocities. It has five regions - flame extinction, stable attached flame, anchored flame, liftoff flame and blow off region. In inverse diffusion flame, lifted flames were observed near the blow off region. As long as flames lift off, flames oscillate by periods. In this oscillating lifted flame region, the frequency of 1 and under were observed in various air and methane jet velocities. Characteristics of lifted flames are also examined by using the ICCD direct image. And intensity of flame chemiluminescence is very different in rising and falling period from photographs. For the present, it is predicted that the changes of flame structure are related with flame oscillation, but more experiments will be needed to make clear the phenomenon.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.19-24
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• 2004

A great deal of exhaust gas inside a combustion room goes out through exhaust pipe but residual gas, is called 'Blow by gas', enters the crankcase through a small gap between the piston and the cylinder wall. Here, if the crankcase isn't vented, this causes many bad effects such as lubricant oil contamination, corrosion by that and crankcase explosion by rising pressure. So most automobiles are constituted with a PCV(Positive Crankcase Ventilation) system to prevent previous problems. PCV valve is the most important part in this ventilation system. When companies are manufacturing new cases, engineers are designing it depending on their experiments than theoretical knowledges. Much efforts and times are needed for new development. This study will show quantitative results to increase the possibilities.