• Journal of Chest Surgery
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• v.17 no.4
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• pp.729-734
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• 1984

Bochdalek hernia is a type of congenital diaphragmatic defect in the posterolateral portion of the diaphragm. The defect is usually Lt. sided due to protective effect of liver on right. Sex distribution is male preponderance [2:1] and it is diagnosed during neonate, mostly first 24 hours, due to severe respiratory distress. We experienced a rare case of old aged female patient with congenital Bochdalek hernia on Rt. side which was found incidentally during treatment of spontaneous pneumothorax of Rt. side. 17 year old female patient was admitted to CS department for chest discomfort on right and mild dyspnea with duration of 20 days. Under the diagnosis of spontaneous pneumothorax, Rt. closed thoracostomy and underwater sealed drainage with continuous suction was applied. On follow-up chest x-ray, poorly defined hazy increased density with multiple air-fluid levels in Rt. lower lung field and Lt. subphrenic free air were noted. So, Barium enema was done under the impression of Rt. diaphragmatic hernia, and nearly entire colon proximal to sigmoid was demonstrated in the Rt. hemithorax. Operation was done-for surgical repair of defected diaphragm through Rt. posterolateral thoracotomy. Operative findings were as follows; 1.Hypoplastic Rt. lung, esp. RML & RLL. 2.Nearly entirely intestines were herniated. 3.Diaphragmatic defect was located on posterolateral portion of the diaphragm, about 10x3cm in size with blunt smooth margin. 4.A large bleb on apex of RUL of lung. Herniated intestines were repaired into abdominal cavity manually and defect of diaphragm was repaired with No. I black silk interrupted sutures directly, and bleb was resected. Postoperative courses were uneventful and the patient was discharged with good condition on POD 14th.

• Journal of Chest Surgery
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• v.38 no.1 s.246
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• pp.84-87
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• 2005

Spontaneous hemothorax vary in cause and are rare for hemothorax induced osteochondroma. Sometimes hemothroax is reported due to osteochondroma induced injury of diaphragm, lung, pericardium, heart, or pleura. We report a patient with diaphragm laceration due to osteochondroma.

• Computers and Concrete
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• v.14 no.2
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• pp.109-125
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• 2014

The force transfer mechanism in positive moment continuity details for prestressed concrete girder bridges is investigated in this paper using a three-dimensional detailed finite element model. Positive moment reinforcement in the form of hairpin bars as recommended by the National Cooperative Highway Research Program Report No 519 is incorporated in the model. The cold construction joint that develops at the interface between girder ends and continuity diaphragms is also simulated via contact elements. The model is then subjected to the positive moment and corresponding shear forces that would develop over the service life of the bridge. The stress distribution in the continuity diaphragm and the axial force distribution in the hairpin bars are presented. It was found that due to the asymmetric configuration of the hairpin bars, asymmetric stress distribution develops at the continuity diaphragm, which can be exacerbated by other asymmetric factors such as skewed bridge configurations. It was also observed that when the joint is subjected to a positive moment, the tensile force is transferred from the girder end to the continuity diaphragm only through the hairpin bars due to the lack of contact between the both members at the construction joint. As a result, the stress distribution at girder ends was found to be concentrated around the hairpin bars influence area, rather than be resisted by the entire girder composite section. Finally, the results are used to develop an approach for estimating the cracking moment capacity at girder ends based on a proposed effective moment of inertia.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.734-741
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• 2008

At-rest and active earth pressure in plane strain condition have been applied to the design of cylindrical retaining walls. But many researchers have indicated that the earth pressure on the cylindrical retaining walls would be smaller than in plane strain condition due to wall deformation and stress relief. In this paper, the distribution of earth pressure acting on diaphragm wall of a shaft in dry sand was predicted by using the convergence confinement method and model test was performed to verify the estimated values. Test results showed that the earth pressure acting on the diaphragm wall of a shaft was expected to be 1.1~1.5 times larger than active earth pressure of plane strain condition and 0.7~0.9 times less than at-rest earth pressure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.401-408
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• 2003

A CAD program for metal bellows diaphragm was developed in this study. This program was written in AutoLISP on the AutoCAD system with a personal computer. Basic design concept used in this program is composition of a convolution that is tangent to two lines and 5 circles from given design parameters(initial radius, inner and outer diameter, thickness, pitch, etc.). The effects of altering some design parameters on stress distribution and fatigue life of bellows were estimated using commercial FEM code, NISAII. As a result, the metal bellows diaphragm was successfully designed by the CAD program. It is used to model a bellows geometry in pre-processor of FEM code. The FEM result shows that stress is dependent on straight line length, bellows diameter with same span, and fatigue life is also affected by design parameters.

• The Journal of the Acoustical Society of Korea
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• v.14 no.5
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• pp.29-35
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• 1995

Nonlinear distortion arising from the nonlinear movement of the loudspeaker diaphragm degradates the tone quality. The distortion is, in low frequency range, mainly caused by nonlinear characteristics of the suspension stiffness and the force factor. In this paper, the nonlinear suspension stiffness and the nonlinear force factor are modeled to the quadratic functions and a method is proposed to determine their coefficients. An additional mass to the diaphragm moved the quiescent point of the diaphragm and uncoupled the stiffness and the force factor. This made it possible to deter mine the coefficients of the nonlinear suspension stiffness by measuring the resonance frequencies at several quiescent points. The coefficients of the nonlinear force factor are then determined by fitting the curve which is calculated from the waveforms of input voltage and input current, and the displacement of the diaphragm at resonance frequency.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.725-732
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• 2006

This study has been started for the development of a refined live load distribution formula that has safety and precision toward I type prestressed concrete girder bridge. This type of bridge is mainly applied to short span bridges that are $25{\sim}40m$ in length. Based on various structure analysis models that are currently being applied as preceding studies for the development of live load distribution method. an analysis of flexural stiffness ratio for barrier and diaphragm has been performed. As the result of parametric analysis for the changes in flexural stiffness ratio, the effect of barrier on load distribution showed as insignificant in all structural analysis models while analyzing the deflection distribution. Also. the deflection distribution of the models with stiffness of 25% in which the diaphragm eccentricity is accounted for as same as the models with stiffness of 100% in which the diaphragm eccentricity is unaccounted for. This results are verified through the comparison with a experimental data.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.8
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• pp.790-796
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• 2013

Micro-speaker diaphragms play an important role in generating a desired audio response. The diaphragm is generally a circular membrane, and the cross section is a double dome, with an inner dome and an outer dome. To improve the sound quality of the speaker, a number of corrugations may be included in the outer dome region. In this study, the role of these corrugations is investigated using two kinds of finite element method (FEM) calculations. Structural FEM modeling was carried out to investigate the change in stiffness of the diaphragm when the corrugations were included. Modal FEM modeling was then carried out to compare the natural frequencies and the resulting vibrational modes of the plain and corrugated diaphragms. The effects of the corrugations on the vibration characteristics of the diaphragm are discussed.

• Structural Engineering and Mechanics
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• v.64 no.2
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• pp.195-204
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• 2017

Analytical and experimental studies of the innovative pipe in pipe damper have been recently investigated by the authors. In this paper, by adding lead or zinc infill or slit diaphragm inside the inner pipe, it is tried to increase the equivalent viscous damping ratio improving the cyclic performance of the recently proposed multi-level control system. The damper consists of three main parts including the outer pipe, inner pipe and added complementary damping part. At first plastic deformations of the external pipe, then the internal pipe and particularly the added core and friction between them make the excellent multi-level damper act as an improved energy dissipation system. Several kinds of added lead or zinc infill and also different shapes of slit diaphragms are modeled inside the inner pipe and their effectiveness on hysteresis curves are investigated with nonlinear static analyses using finite element method by ABAQUS software. Results show that adding lead infill has no major effect on the damper stiffness while zinc infill and slit diaphragm increase damper stiffness sharply up to more than 10 times depending on the plate thickness and pipe diameter. Besides, metal infill increases the viscous damping ratio of dual damper ranging 6-9%. In addition, obtained hysteresis curves show that the multi-level control system as expected can reliably dissipate energy in different imposed energy levels.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.204-211
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• 2002

Today\`s industrialized plants are required to reduce SOx emitted from stacks at factories, utility power stations, etc. For this purpose, flue gas desulfurization(FGD) system is installed in thermal power plant and gas-gas heater(GGH) is used to play a vital role to reheat the wet treated gas from FGD. The sector plates are located at cold and hot sides of gas-gas heater. They serve as sealing to prevent mixing treated and untreated gases. Therefore, the deformation of the sector plate due to its dead weight and gas pressure should be considered as major factor for the sector plate design. And finite element analysis(FEA) for rotor part in GGH is performed with original model and two weight-reduced models with different diaphragm thickness, respectively. Stress concentrations at rotor diaphragm happen due to the dead weight, pressure difference between treated and untreated gas, and thermal distribution in the rotor. As the thickness of diaphragm is decreased, the stress level is increased. The direction of treated gas and untreated gas flow may affect the stress level.