• Journal of Advanced Marine Engineering and Technology
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• v.34 no.5
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• pp.718-724
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• 2010

This paper studies the differences due to the wall effect in propeller open water(POW) characteristics tested in a towing tank and in a medium size cavitation tunnel(CT). When the advanced velocity of the propeller is defined as the flow velocity measured in the plane of propeller, POW characteristics resulting from CT has a better relationship with them of towing tank. To obtain the wall effect in the propeller plane, numerical computation using the lifting panel theory is performed with and without the wall around a propeller. Then, POW results in CT are corrected based on the wall effect from numerical results. The POW results obtained from this procedure show a better agreement with the experimental results in the towing tank.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.409-414
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• 2010

Purpose: Poland's syndrome encompasses a constellation of congenital chest wall, breast, and upper extremity deformities. We would like to present several techniques, which may be combined if necessary, used to treat the forms involving both the breast and chest wall according to the degree of deformity. Methods: In a retrospective series of 9 patients (3 men and 6 women), we report our experience with reconstructing breast and chest contour deformities associated with Poland syndrome. We recorded their age, gender, the surgical techniques, and the grade in Poland's syndrome according to the classification of Foucras. Results: The breast and chest wall deformities associated with Poland syndrome can be treated in individualized fashion according to the classification of Foucras. In case of 3 male patients with gradeI, II, the latissimus dorsi muscle pedicled flap improved the chest contour deformity. 3 female patients with grade II underwent the latissimus dorsi muscle pedicled flap with breast implant. 2 female patients with gradeIunderwent breast reconstruction with breast implant and fat injection each other. One female patient with severe chest wall deformity (grade III) underwent breast reconstruction using the free TRAM flap. All patients were satisfied with the results without specific complications. Conclusion: The Individualized correction for this syndrome according to the degree of patient's deformity and preference made the overall satisfaction of the patients high.

• Journal of Chest Surgery
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• v.7 no.1
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• pp.93-100
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• 1974

This is a case report of successful surgical correction of coarctation of the aorta associated with the patent ductus arteriosus and the persistent left superior vena cava. The patient was a 15 year old girl and congenital heart anomaly was suspected at the sixth month after birth. Afterward there has been no embarrassing symptoms until the day of operation except slight dyspnea on exertion, The diagnosis of coarctation of the aorta and the patent ductus arteriesus detected by physical signs and X-ray studies including aortography. In the first place, coarctation of the aorta was corrected with following procedure: partial resections of the aortic wall just above and below the coarctating line of the aorta and removal of diaphragmatic structure of coarctation performed by. cross clamping aorta above and below coarctation, and then the defect of the aortic wall was closed by lateral aortorrhapic suture with atraumatic needle 3-0 silk continuously [Fig. 6]. In the second place, the patent ductus arteriosus was closed with double ligation method. The persistent left superior vena cava left as it has been, because there has been no evidence of hemodynamic abnormal shunt. After operation, excellent result was obtained; blood pressure in the upper and lower extremities was normalized and subjective complains of hypertension in the upper extremity was disappeared.

• Journal of International Society for Simulation Surgery
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• v.1 no.1
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• pp.7-12
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• 2014

Purpose Surgical correction of various occular problems which do not have visual problem in plastic surgical area is to normalize the appearance of the face by restoring the normal position of orbit and eyeball. With development of surgical technique, the orbit can be restored exactly in trauma patient and can be moved totally in hypertelorism, as an example of congenital disease. All these surgeries are based on the hypothesis that the position of oclular glove moves in the plane in a quantitatively predictable reationship to osseous orbit movement. However, no studies have critically evaluated between the change of periorbital soft tissue and the outcome of the surgical correction, because there is no method of objective, quantitave evaluation of the periorbital soft tissue. Method Author suggest the methodology for quantitative assessment of ocular and periocular fat changes using the manipulation of digital images of computed tomographic scan. Results The method was allowed to evaluate inter-dacryon distance, inter-centroid distance, movement of the medial orbital wall, movement of the lateral orbital wall, alteration of thickness of the lateral periorbital fat as indicator of movement of the orbital wall and orbit in the patient with congenital periorbital anomaly and postoperative periorbital surgery. The goal of surgical correction of various occular problems which do not have visual problem in plastic surgical area is to normalize the appearance of the face by restoring the normal position of orbit and eyeball. With development of surgical technique, the orbit can be restored exactly in trauma patient and can be moved totally in hypertelorism, as an example of congenital disease. All these sugeries are based on the hypothesis that the position of oclular glove moves in the plane in a quantitatively predictable relationship to osseous orbit movement. However, no studies have critically evaluated between the change of periorbital soft tissue and the outcome of the surgical correction, because there is no method of objective, quantitave evaluation of the periorbital soft tissue. In this report, author suggest the methodology for quantitative assessment of ocular and periocular fat changes using the manipulation of digital images of computed tomographic scan. Conclusion The method suggested is objective and accurate method in measurement of the orbital contents. It takes time and is not easy to do, however, this kind of measurement for fine structures will be more easily available in near future.

• Transactions of Materials Processing
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• v.18 no.6
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• pp.488-493
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• 2009

The very big springback of advanced high strength steel(AHSS) sheets invokes undesired shape defects, which can be generally eliminated by die correction or process parameter control. The springback reduction by controlling the forming process parameters is easy for the application, but limited for the bulky achievement. In this study, the effective die correction method, which obtains the modification of tool shape from the relationship between die design variable and springback, is introduced and is applied to the TWB tool of automotive side rail to show the validity and usefulness. Among the die correction trials repeatedly performed, the first trial is carried out by correcting the tool shape to the opposite direction to the springbacks of several tool sections. Next trials are done by extrapolating the springbacks of among the original tool uncorrected and the tools corrected negative amounts of the springback and by finding tool shapes without springbacks. After the angle of side wall and radius of curvature of horizontal bottom floor are chosen as design variables in the tool design of side rail, the tool shape is corrected 3 times. The accuracy of final shape within the assembly limit of 1mm and the springback reduction of 75.8% compared to the uncorrected tool are achieved.

• Current Optics and Photonics
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• v.4 no.6
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• pp.500-508
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• 2020

The rifling angle of artillery is an important parameter, and its determination plays a key role in the stability, hit rate, accuracy and service life of artillery. In this study, we propose an optical measurement method for the rifling angle based on angle error correction. The method is based on the principle of geometrical optics imaging, where the rifling on the inner wall of the artillery barrel is imaged on a CCD camera target surface by an optical system. When the measurement system moves in the barrel, the rifling image rotates accordingly. According to the relationship between the rotation angle of the rifling image and the travel distance of the measurement system, different types of rifling equations are established. Solving equations of the rifling angle are deduced according to the definition of the rifling angle. Furthermore, we added an angle error correction function to the method that is based on the theory of dynamic optics. This function can measure and correct the angle error caused by the posture change of the measurement system. Thus, the rifling angle measurement accuracy is effectively improved. Finally, we simulated and analyzed the influence of parameter changes of the measurement system on rifling angle measurement accuracy. The simulation results show that the rifling angle measurement method has high measurement accuracy, and the method can be applied to different types of rifling angle measurements. The method provides the theoretical basis for the development of a high-precision rifling measurement system in the future.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.215-218
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• 1999

A general structural model, which is an extension of the Vlassov theory, is developed for the analysis of composite rotor blades with elastic couplings. A comprehensive analysis applicable to both thick-and thin-walled composite beams, which can have either open- or closed profile is formulated. The theory accounts for the effects of elastic couplings, shell wall thickness, and transverse shear deformations. A semi-complementary energy functional is used to account for the shear stress distribution in the shell wall. The bending and torsion related warpings and the shear correction factors are obtained in closed form as part of the analysis. The resulting first order shear deformation theory describes the beam kinematics in terms of the axial, flap and lag bending, flap and lag shear, torsion and torsion-warping deformations. The theory is validated against experimental results for various cross-section beams with elastic couplings.

• Coupled systems mechanics
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• v.7 no.4
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• pp.421-440
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• 2018

In this study, a computational method for wall shear stress combined with an implicit direct-forcing immersed boundary method is presented. Near the immersed boundaries, the sub-grid stress is determined by a wall model in which the wall shear stress is directly calculated from the Lagrangian force on the immersed boundary. A coupling mathematical model of the transition process for a model Francis turbine comprising turbulent flow and rotating rigid guide vanes is established. The spatiotemporal distributions of pressure, velocity, vorticity and turbulent quantity are gained with the transient process; the drag and lift coefficients as well as other forces (moments) are also obtained as functions of the attack angle. At the same time, analysis is conducted of the characteristics of pressure pulsation, velocity stripes and vortex structure at some key parts of flowing passage. The coupling relations among the turbulent flow, the dynamical force (moment) response of blade and the rotating of guide vane are also obtained.

• Journal of ILASS-Korea
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• v.13 no.1
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• pp.22-27
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• 2008

The false diffusion occurs generally when the flow is oblique to the grid lines and when there is a non-zero gradient of the dependent variable in the direction normal to the flow. This numerical problem can overestimate diffusion terms in the continuous phase, causing the numerical inaccuracy for the simulation of impinging sprays on inclined walls because most of spray calculation uses rectangular grid system. Therefore, the main objective of this article is to investigate numerically the influence of false diffusion on numerical simulation for spray-wall impingement on inclined walls. It is found that unlike the spray impingement normal to the wall, the numerical diffusion exists in the case when diesel sprays impinge on the inclined walls with different angles. The results show that the correction function should be considered for accurate prediction of spray penetration length and more elaborate numerical schemes should be utilized to reduce the false diffusion.

• Archives of Craniofacial Surgery
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• v.20 no.6
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• pp.361-369
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• 2019

Background: Trauma is one of the most common causes of enophthalmos, and post-traumatic enophthalmos primarily results from an increased volume of the bony orbit. We achieved good long-term results by simultaneously using an anatomical absorbable implant and iliac bone graft to correct post-traumatic enophthalmos. Methods: From January 2012 to December 2016, we performed operations on seven patients with post-traumatic enophthalmos. In all seven cases, reduction surgery for the initial trauma was performed at our hospital. Hertel exophthalmometry, clinical photography, three-dimensional computed tomography (3D-CT), and orbital volume measurements using software to calculate the specific volume captured on 3D-CT (ITK-SNAP, Insight Toolkit-SNAP) were performed preoperatively and postoperatively. Results: Patients were evaluated based on exophthalmometry, clinical photographs, 3D-CT, and orbital volume measured by the ITK-SNAP program at 5 days and 1 year postoperatively, and all factors improved significantly compared with the preoperative baseline. Complications such as hematoma or extraocular muscle limitation were absent, and the corrected orbital volume was well maintained at the 1-year follow-up visit. Conclusion: We present a method to correct enophthalmos by reconstructing the orbital wall using an anatomical absorbable implant and a simultaneous autologous iliac bone graft. All cases showed satisfactory results for enophthalmos correction. We suggest this method as a good option for the correction of post-traumatic enophthalmos.