• Journal of Welding and Joining
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• v.2 no.1
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• pp.41-48
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• 1984

Recrystallization technique was applied to analyze plastic strain at the notch tip of coarse grain HAZ in mild steel (SB 41) and high strength steel (SA 588). The notch tip of specimen was deformed by three point bending. Accumulated displacement (Crack Opening Displacement ${delta}t$) by the monotonic and cyclic loading under room temperature and hot strain embrittlement temperature ($250^{\circ}C$) was 0~1.0mm. Recrystallization heat treatment conditions were $650^{circ}C{ imes}3hr$ for SB 41 and $700^{circ}C{ imes}3hr$ for SA 588. The experimental results obtained were as follows ; 1) Distribution of the effective plastic strain at plastic zone was appeared by the function of crack opening displacement, and plastic zone or the effective plastic strain increased with crack opening displacement. 2) Plastic strain at notch tip of HAZ due to accumulated hot strain calculated as follows. .epsilon. over bar $_{p}$ = .epsilon. over bar $_{cr}$ (x/ $R_{x}$ ) $^{m}$ (m=0.25) 3) Work hardending ratio of notch tip for hot strain was linearly increased with .epsilon. over bar $_{max}$ and dependent upon the material types.s.

• Archives of Plastic Surgery
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• v.41 no.1
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• pp.3-11
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• 2014

Background This study aimed at overcoming the disadvantages of septal extension grafts and keeping the nasal tip as natural as possible by using different forms of the graft and additional supporting methods depending on the case. Methods Among 458 patients who received a septal extension graft from March 2008 to September 2011, 107 patients were selected who underwent at least a 6-month follow-up. Patients were categorized according to the primary objective of the operation; an upturned tip correction or tip lengthening, tip lengthening with tip projection, or retracted columella correction. Each group of patients received a different type of septal extension graft out of 3 different types of grafts based on the purpose of the operation. The evaluation of the results was made from by comparing preoperative and postoperative photographs of the tip angle, projection, and nasolabial angle. Results The average tip angle for the patients in the upturned tip correction group was reduced to 98.3 from 124.9 degrees. For the patients in the tip lengthening with tip projection group, the average tip angle was reduced to 96.8 from 122.4 degrees and the average tip projection was increased to 27.5 from 23.2 mm. The average nasolabial angle for the patients in the retracted columella correction group was increased to 94.6 from 74.8 degrees. Conclusions Sufficient nasal tip lengthening and projection could be achieved by applying a septal extension graft using the graft best suited for the group of patients categorized by surgical objective.

• Archives of Plastic Surgery
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• v.41 no.6
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• pp.630-637
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• 2014

A long nose with a drooping tip is a major aesthetic problem. It creates a negative and aged appearance and looks worse when smiling. In order to rectify this problem, the underlying anatomical causes should be understood and corrected simultaneously to optimize surgical outcomes. The causes of a drooping tip of a long nose are generally classified into two mechanisms. Static causes usually result from malposition and incorrect innate shape of the nasal structure: the nasal septum, upper and lower lateral cartilages, and the ligaments in between. The dynamic causes result from the facial expression muscles, the depressor septi nasi muscle, and the levator labii superioris alaeque nasi muscle. The depressor septi nasi depresses the nasal tip and the levator labii superioris alaeque nasi pulls the alar base upwards. Many surgical methods have been introduced, but partial approaches to correct such deformities generally do not satisfy East Asians, making the problem more challenging to surgeons. Typically, East Asians have thick nasal tip soft tissue and skin, and a depressed columella and alar bases. The authors suggest that multifactorial approaches to static and dynamic factors along with ancillary causes should be considered for correcting the drooping tip of the long noses of East Asians.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.24-32
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• 2004

The effects of guide vanes and tip clearances on the characteristics nf axial flow fans are investigated both computationally and experimentally. Performance test of fans carried out in full scale shows considerable effects of tip clearance between rotor tip and duct on the characteristics of fans. The tested results are compared with the computation based on the finite volume method to solve the Navier-Stoke equations with $textsc{k}$-$\varepsilon$ turbulence model. The comparison shows good agreements between experimental and computational results. In addition, the effects of shape of guide vanes are numerically studied. The results show that increased volume of separated region around the guide vane reduces the recovery of tangential component of kinetic energy in the wake, resulting in loss of efficiency

• Archives of Plastic Surgery
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• v.41 no.1
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• pp.12-18
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• 2014

In patients having a short nose with a short septal length and/or severe columellar retraction, a septal extension graft is a good solution, as it allows the dome to move caudally and pushes down the columellar base. Fixing the medial crura of the alar cartilages to a septal extension graft leads to an uncomfortably rigid nasal tip and columella, and results in unnatural facial animation. Further, because of the relatively small and weak septal cartilage in the East Asian population, undercorrection of a short nose is not uncommon. To overcome these shortcomings, we have used the septal extension graft combined with a derotation graft. Among 113 patients who underwent the combined procedure, 82 patients had a short nose deformity alone; the remaining 31 patients had a short nose with columellar retraction. Thirty-two patients complained of nasal tip stiffness caused by a septal extension graft from previous operations. In addition to the septal extension graft, a derotation graft was used for bridging the gap between the alar cartilages and the septal extension graft for tip lengthening. Satisfactory results were obtained in 102 (90%) patients. Eleven (10%) patients required revision surgery. This combination method is a good surgical option for patients who have a short nose with small septal cartilages and do not have sufficient cartilage for tip lengthening by using a septal extension graft alone. It can also overcome the postoperative nasal tip rigidity of a septal extension graft.

• The KSFM Journal of Fluid Machinery
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• v.15 no.1
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• pp.41-45
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• 2012

The effects of inducer tip clearance on the suction performance of a pump for turbopumps are investigated. Experiments for the pump with inducer tip clearances of 1.8% and 1.4% of blade height were performed. The experimental results showed that the suction performance of the pump increased as the tip clearance decreased. It seems that the suction performance of the pump becomes better with smaller tip clearances because the strength of the inducer backflow becomes weak with the decreased tip clearance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.11
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• pp.849-854
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• 2013

Experimental study was conducted to investigate aerodynamic interference effect of wing tip vortex in formation flight of high speed aircraft. In formation flight, wing tip vortex produced by leading aircraft can affect on the aerodynamic characteristics of trailing aircraft. The interference effect of flow is varied with distances between wing tips of leading and trailing aircraft. It is confirmed, in this study, that the interference of wing tip vortex generated from the leading aircraft makes the aerodynamic forces and moments of the trailing aircraft with the vertical or horizontal positions of the trailing aircraft. Especially, the lift coefficients of trailing aircraft were highly increased at y/b=-0.125, z/b=0.0 or deeply decreased at y/b=-0.5, z/b=0.38. The interfering pattern of wing tip vortices from two aircraft is precisely observed.

• Resources Recycling
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• v.25 no.6
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• pp.41-49
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• 2016

The present study was intended to prepare cobalt oxide ($Co_3O_4$) powder of average particle size 50 nm or less by spray pyrolysis reaction using the raw cobalt chloride ($CoCl_2$) solution, in order to identify the change in the nature of the particles according to the change in the nozzle tip size. When the nozzle tip was 1 mm, it turned out that most of the droplets were spherical and the surface showed very tight structure. The average particle size of the finally formed particles was 20-30 nm. When the nozzle tip size was 2 mm, some of the droplets formed were spherical, but a considerable part of them showed severely disrupted form. particles formed showed an average particle size of 30 - 40 nm. For the nozzle tip size of 5 mm, spherical droplets were almost non-existent and most were in badly fragmented state. The tightness of surface structure of the droplets has greatly been reduced compared with other nozzle tip sizes. Average size of the formed particles was about 25 nm. As the nozzle tip size increased from 1 mm to 2 mm and 3 mm, the intensities of the XRD peaks have changed little, but significantly been reduced when the nozzle tip size increased to 5mm. As the nozzle tip size increased from 1 mm to 2 mm, the specific surface area of the particles decreased, but the nozzle tip size increased to 5mm, the specific surface area remarkably increased.

• The KSFM Journal of Fluid Machinery
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• v.13 no.2
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• pp.41-47
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• 2010

The effect of incidence angle on the three-dimensional flow and aerodynamic loss in the tip leakage flow region downstream of a turbine rotor cascade has been investigated for two tip gap-to-chord ratios of h/c=0.0% (no tip gap) and 2.0%. The incidence angle is changed to be $i=-10^{\circ}$, $0^{\circ}$, and $5^{\circ}$. The results show that for $i=5^{\circ}$, secondary flows including the passage vortex are intensified noticeably, and there is a strong interaction between the passage and tip leakage vortices. For $i=-10^{\circ}$, however, the passage vortex is weakened significantly, so that there exists only a strong leakage-jet-like secondary flows near the casing wall. For h/c=0.0% and 2.0%, aerodynamic loss tends to increase with increasing i from $-10^{\circ}$ to $5^{\circ}$. A small increment of i in its positive incidence range results in a remarkable aerodynamic loss increase, while increasing i in the negative incidence range leads to a small change in the aerodynamic loss generation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.7
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• pp.516-523
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• 2013

The tip clearance effect on counter-rotating ducted fan of VTOL UAV in hovering condition, was investigate using computational analysis. The $k-{\omega}$ SST turbulence model is employed in this study. The numerical results of baseline model are validated by wind tunnel test in hovering and forward conditions. It is observed that if tip clearance of one rotor in the counter-rotating ducted fan increase then the thrust coefficient of another rotor increases. In Addition to this, when the tip clearance of the rear rotor increases, the thrust of the ducted fan is improved due to increasing of average total pressure at exit plane.