• Journal of Veterinary Clinics
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• v.39 no.6
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• pp.366-372
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• 2022

A 2-year-old, spayed female, American shorthair cat presented with acute weight loss, tachypnea, and dyspnea. The cat had grade V holosystolic murmur and systemic hypotension. Echocardiography showed a 9 mm defect in the ventricular septum, left-to-right dominant bi-directional shunt, right ventricular hypertrophy, pulmonary stenosis, pulmonary hypertension, and overriding aorta. The cat was diagnosed with a Tetralogy of Fallot. The cat was treated with furosemide, pimobendan, ramipril, and sildenafil. Treatment reduced pulmonary infiltration, pulmonary vessel enlargement, and main pulmonary artery bulging. However, right-to-left flow increased over time and right ventricular outflow tract velocity was elevated. Currently, the patient has maintained an improved state for 1 year. This case report described a severe inherited feline Tetralogy of Fallot case that was successfully managed for a long time.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.10
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• pp.1417-1425
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• 2014

The selection of morphologically normal spermatozoa is critical to obtain high breeding performances in boar breeding farms and artificial insemination (AI) centers. Parameters for the selection of semen mainly include total sperm motility, concentration, and morphology. However, these primary parameters are often not reliable for discriminating between normal and abnormal, non-fertilizable spermatozoa. The present study was designed to compare the motion characteristics, fertilization ability using in vitro fertilization (IVF), and acrosome formation of the semen from boars having low (boar number 2012) and normal (boar number 2004 and 2023) breeding performances. The ultimate goal was to identify additional simple and easy criteria for the selection of normal sperm. There was no significant difference between boar 2004 and boar 2023 sperm total motility in computer assisted sperm analysis. However, boar number 2012 semen presented a significantly reduced population of rapid moving spermatozoa and an increased population of slow moving spermatozoa compared to boar numbers 2004 and 2023. Analysis of detailed motion characteristics revealed that sperm from boar number 2012 had significantly reduced motility in progressiveness, average path velocity, straight-line velocity (VSL), curvilinear velocity (VCL), straightness, and linearity. The assessment of the fertilizing ability by IVF also showed that sperm from boar number 2012 showed a fertility rate of 3.4%, whereas sperm from boar number 2023 had a fertility rate of 75.45%. Interestingly, most of the sperm nuclei were found on the peripheral area of the oocytes, suggesting that the sperm from boar number 2012 lacked penetration ability into the oocyte zonapellucida. The acrosome formation analysis using Pisum sativum agglutinin staining demonstrated that the sperm from boar number 2012 had a defect in acrosome formation. Consequently, primary parameters for selecting semen before AI such as motility are not sufficient to select normal and fertilizable spermatozoa. In conclusion, the present study suggests that the acrosome staining and detailed motion characteristics such as progressiveness, VCL, and VSL should be included in determining semen quality together with primary parameters for successful AI and high breeding performance in the swine industry.

• Journal of radiological science and technology
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• v.37 no.2
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• pp.117-124
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• 2014

This study has investigated the effects of the defects in the probe elements influence Doppler images in the medical ultrasonic scanners. This work was implemented that the quality of Doppler images depended on the extent and location of the probe element defected. The probe performance was rated in terms of the number of piezoelectric elements lost and this was studied in the experiment by electrical disconnection to the elements. The results showed that Doppler velocity became rapidly reduced as the defected elements encountered with the element group activated at the Doppler mode, not as the flow velocity. The effect of the probe defect is decreased when the defects occurred at the element group activated for Doppler mode, as was increased the number of the elements. It was observed that the higher the flow velocity of Doppler flow phantom is, the wider the spectrum of Doppler is. And the Doppler velocity soared up and the dispersion of image brightness is increased when the defected elements got out of the elements activated at Doppler mode. The result showed that TADVP(time-average-Doppler-velocity-profile) is decreased with the increase of the probe element defect, especilly in the region of high frequency. It is expected that the research of various defects of probe elements are needed, and this study can be practical tools for probe based ultrasonic QA in the future.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.1
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• pp.75-82
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• 2007

As one of the main support systems, rock bolts play a crucial role in the reinforcement of tunnels. Numerical and experimental studies using a transmission method of ultrasonic guided waves are performed to evaluate the integrity of rock bolts encapsulated by grouting paste. Numerical simulations using "DISPERSE" are carried out for the selection of the optimal experimental setup, i.e. non-destructive testing (NDT) system of the rock bolt. Based on results of the numerical simulation, the calculated frequency range for NDT testing is between 20kHz and 70kHz with the first longitudinal L(1) mode. Laboratory transmission tests are performed by attaching the piezo electric sensor at the tip of the rock bolt before embedding. Both of analytical and experimental results show that the amplitude of signals as well as the wave velocity increases with increase in the defect ratio of grouting paste. The defect in grouting paste means that the space around the rock bolt is not fully filled with the grouting paste. Experimental results also show that the increase of the wave velocity is more sensitive to the defect ratio increase than that of the amplitude. This study demonstrates that the transmission technique of ultrasonic guided waves may be a valuable tool in the evaluation of the rock bolt integrity.

• Journal of Trauma and Injury
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• v.36 no.3
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• pp.258-260
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• 2023

Traumatic rupture of the right hemidiaphragm occurred following a high-velocity motor vehicle collision in the case presented herein. The resulting herniation of small bowel loops into the thorax resulted in hemodynamic and respiratory compromise due to pressure effects on the right heart and major vessels. The patient's hemodynamic status improved with reduction of enterothorax, and the diaphragmatic defect was repaired. We discuss the available literature and learning points from this rare case.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.352-356
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• 2007

In this study, a rigid-plastic finite element method is applied to simulating a ring rolling process of the inner race cage of a constant velocity joint for the passengers' cars. The ring rolling process is mathematically modeled by several assumptions. The defect formation at the side ends is predicted in detail. The predictions are compared with the experiments and a good agreement is observed in terms of deformed shape.

• Journal of Korea Foundry Society
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• v.24 no.1
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• pp.3-9
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• 2004

Die casting is "a process in which molten metal is injected at high velocity and pressure into a mold(die) cavity". Casting with smooth surfaces, high dimensional precision, complicated shapes, and reduced weight can be obtained using this process. But this process is susceptible to casting defects such as porosities, scattered chilled layers, hard spots, etc. For preventing casting defects, we developed "low-velocity high pressure die casting technology", "squeeze die casting technology", "heat insulating sleeve lubricant technology", and "direct pouring technology". The "direct pouring technology" is useful for producing molten metal without oxide contamination. It consists of a pumping system which supplies pure molten metal to the die casting machine. By using this technology, we have successfully reduced oxide contamination in castings to 1/20 of that of our previous castings.

• Transactions of Materials Processing
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• v.12 no.2
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• pp.102-109
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• 2003

In the manufacturing process of metal matrix composites parts, thixoforging is one of the most effective forming processes. The major purpose of the current study is to provide the proper conditions such as the die shape, the forging velocity, the forging time, the forging pressure and reinforcement injection velocity and pressure on various defects in thixoforged cylinder liner, filling tests were performed by MAGMA S/W. In order to evaluate the effectiveness of the calculated conditions which is given by computer aided engineering, A357, A380 and SiC$_{p}$/A380 cylind~5$mu extrm{m}$r liner were fabricated under the calculated conditions. SiC$_{p}$/A380 composite billets were fabricated by both the mechanical stirring and electrical magnetic stirring process. Incase fo SiC$_{p}$/A380 composite cylinder liner, reinforcement distribution and effect of reinforcement(SiC$_{p}$) content(10~20 vol. %)and size(5.5~14${\mu}{\textrm}{m}$) on the mechanical properties were investigatedstigated.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.57-64
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• 2004

This study deals with the prediction of defect location which can be occurred in structure. The existing methods was very difficult to be applied to predict it, because of complex numerical formula. The triangulation method proposed in this study can predict the source location easily with small amount of data. The arrival time of wave can be directly converted into the distance between sensors. For this purpose, the propagation velocity was measured by Rayleigh wave, and the propagation behavior was analyzed. The welded workpiece is adapted to investigate for the consideration of jointed part in structure, The propagation velocity of signal was measured in welded workpiece and the revised algorithm of source location was proposed.

• The KSFM Journal of Fluid Machinery
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• v.2 no.4 s.5
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• pp.16-23
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• 1999

The characteristic of unsteady flowfields on gas turbine, particularly on a rotor blade surface has been numerically investigated. The unsteady flow in a rotor blade passage as a result of wake/blade interaction is modeled by the inviscid flow approach, and solved by Euler equations using a time accurate marching scheme. Unsteady flow in the blade passage is induced by periodically moving a wake model across the passage inlet. The wake model used in this study is the Gaussian wate model in which the wake flow is assumed to be parallel with uniform static pressure and uniform relative total enthalpy. Numerical results show that for the case of Ps/Pr=1.5, the velocity and pressure distribution on the blade surfaces have much more complex profiles than for the case of Ps/Pr=1.0.