• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.3
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• pp.419-430
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• 1999

Measurements of local blowing ratio and ammonia-diazo flow visualizations have been conducted for a shower-head film cooling on a first-stage turbine stator. In this study, six rows of normal holes are drilled symmetrically on the semicircular leading edge of a simulated blunt body. The measurements show that for an average blowing ratio based on freestream velocity, M, of 0.5, local average mass flow rate through the first two rows of the holes is less than those through the second and third two rows of the holes, and the fraction of mass flow rate through the first two rows to total mass flow rate has a tendency to increase with the increment of M. The flow visualizations reveal that the injection through the first two row results in inferior film coverage even In the case of M = 0.5, meanwhile the row of holes situated at farther downstream location provides higher film-cooling performances for all tested M. This is because film-cooling effectiveness depends on local mainflow velocity at the hole location as well as the mass flow rate through each row.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.2
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• pp.177-187
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• 2000

Measurements of temperature fields and film-cooling effectiveness have been conducted for a shower-head film cooling on the leading edge of a blunt body, which simulates a first-stage turbine stator. In this study, three injection cases are employed for an average blowing ratio based on freestream velocity, M, of 0.5, 1.0 and 1.5. Two (Case 1), four (Case 2) and six (Case 3) rows of normal holes are symmetrically drilled on the three tested circular-cylinder leading edges. The measurements show that regardless of M, the film-cooling effectiveness increases as the injection row is situated at farther downstream location. In Case 1, the film-cooling effectiveness is highest for M = 0.5 and lowest for M = 1.5. On the contrary, in Case 3, the film-cooling effectiveness is highest for M = 1.0 and lowest for M = 0.5. When M = 0.5, the film coverage by the first row of the injection holes deteriorates as the number of the injection row increases. In particular, the film-cooling effectiveness due to the injection through the first row of the holes in Case 3, has a nearly zero value.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.455-466
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• 2016

Chemical-kinetic parameters of the equilibrium constants to evaluate the reverse rate coefficients in the shock layer of a blunt body and the expanding flows are derived for the temperature range from 300 K to 20,000 K. The expanded equilibrium constants for the chemical reactions of the dissociation, ionization, associative ionization, and neutral and charge exchange reactions of the atmospheric species and carbon materials are proposed in the present work. In evaluating the equilibrium constants, the inter-nuclear potential energies of the molecular species are calculated by the analytical potential function of the Hulburt-Hirschfelder model, and the parameters of the analytical model are determined from the semi-classically calculated RKR potentials. The electronic states and energies of the atoms are calculated by the electronic energy grouping model, and the rovibrational states and energies of each electronic states of the molecules are evaluated by the WKB method. The expanded equilibrium constants for 31 types of the reactions are provided for the best curve-fit functions, and the recombination reaction rate coefficients evaluated from the present equilibrium constants are compared with existing measured values.

• Wind and Structures
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• v.24 no.5
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• pp.465-480
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• 2017

Modelling an equilibrium atmospheric boundary layer (ABL) in computational wind engineering (CWE) and relevant areas requires the boundary conditions, the turbulence model and associated constants to be consistent with each other. Among them, the inflow boundary conditions play an important role and determine whether the equations of the turbulence model are satisfied in the whole domain. In this paper, the idea of modeling an equilibrium ABL through specifying proper inflow boundary conditions is extended to the SST $k-{\omega}$ model, which is regarded as a better RANS model for simulating the blunt body flow than the standard $k-{\varepsilon}$ model. Two new sets of inflow boundary conditions corresponding to different descriptions of the inflow velocity profiles, the logarithmic law and the power law respectively, are then theoretically proposed and numerically verified. A method of determining the undetermined constants and a set of parameter system are then given, which are suitable for the standard wind terrains defined in the wind load code. Finally, the full inflow boundary condition equations considering the scale effect are presented for the purpose of general use.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.182-189
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• 1993

To improve the resolution of complex flow field features, grid adaptation scheme of Anderson has been revised, which was based on the Poisson grid generator of Thompson. Anderson's original scheme adapts the grid to solution automatically, but if flow field is more or less complex, then the adaptivity is weak. So the technique of using threshold which is used in unstructured grid system is adopted. The regions of large variation in the solution are marked by marking function which has the property of total variation of the solution, and these regions have same values of weight but other regions are neglected. This updated method captures shocks clearly and sharpy. Four examples are demonstrated, (1) Hypersonic flow past a blunt body, (2) High speed inlet analysis, (3) Supersonic flow of M=1.4 over a 4% biconvex airfoil in a channel, (4) Hypersonic shock-on-shock interaction at M=8.03.

• Journal of Trauma and Injury
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• v.22 no.1
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• pp.119-122
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• 2009

Traumatic abdominal wall hernia after blunt abdominal trauma is rare. The prevalence of traumatic abdominal wall hernia in published series is approximately 1%. Recently, by the use of computed tomography has increased the number of occult traumatic abdominal wall hernias (TAWH). A 47-year-old woman presented to the emergency room soon after a traffic accident. She was fully conscious and complained of diffuse, dull, abdominal pain. She had a seat belt on at the time of the accident. Initial computed tomography showed that the lower left abdominal wall had a defect and that a part of the small bowel had herniated through the defect. During the operation, we made an incision at the defect site and confirmed the defect. The defect size was about $15{\times}5cm$. The muscle layers were repaired in layers with absorbable sutures. Prolen mesh was layed down and fixed on the site of the repaired muscle defect. After 6 months, hernia had not recurred, and no weakness of the repaired abdominal wall layers was identified. The patient's postoperative body functions were normal.

• Journal of Veterinary Clinics
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• v.33 no.2
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• pp.116-121
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• 2016

A 1.83 kg, 9-year-old, spayed female Yorkshire Terrier was referred to the Veterinary Medical Teaching Hospital of Konkuk University for evaluation of an intra-abdominal mass with a week history of vomiting and diarrhea. On physical examination, survey radiography, abdominal ultrasonography, and computed tomography, a huge firm mass was identified in the mid-caudal abdomen. Surgical exploration of the abdominal cavity was performed to remove the mass. The encapsulated mass adhered to the mesentery, tail of the spleen, small intestine, omentum, and right lobe of the pancreas was removed using blunt dissection with dry gauze and cotton swabs. Macroscopic and histopathological examination revealed that the mass was foreign-body granuloma consistent with gauze fiber. Plain abdominal radiography demonstrated no remarkable findings 8 months post-operatively. There was no evidence of vomiting, diarrhea, coughing, difficulty breathing, and cyanosis on exertion 13 months post-operatively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.4
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• pp.286-290
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• 2021

Objectives: The use of fat grafts in maxillofacial sculpturing is currently a common technique. Unlike fillers, autologous fats unite with facial tissues, but long-term results may still be unsatisfactory. Sharing long-term follow-ups can be helpful in making outcomes more predictable. Materials and Methods: The data from patients who were admitted from 2014 to 2016 for fat augmentation were collected. In all cases, fat grafts were injected by blunt cannula using a tunneling technique in different planes. A fan shape order for the malar, periorbital, nasolabial fold, mandibular angle and body, and perioral area was established. Results: Autologous fat was used for different sites of the maxillofacial regions. Of 15 patients, two patients were not satisfied due to fat graft resorption. For this, further injections were performed six months after the first injection using preserved fat grafts. One patient continued to be dissatisfied. There were no other complications related to fat transplants. Conclusion: Fat transplantation is a safe, reliable, and non-invasive method for facial contour and facial soft tissue defect restoration. Additional methods such as mesenchymal stem cells along with fat injection increase the survival rate of transferred fat.

• Wind and Structures
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• v.38 no.2
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• pp.93-107
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• 2024

A π-shaped composite deck in the form of an open section is a type of blunt body that is highly susceptible to wind loads. To investigate its vortex-induced vibration (VIV) performance, a large-scale (1/20) section model of a cable-stayed bridge with a main span of 650 m was tested in a wind tunnel. The vibration suppression mechanism of the countermeasures was analyzed using computational fluid dynamic. Experimental results demonstrate that the vertical and torsional VIVs of the original section can be suppressed by combining guide plates with a tilt angle of 35° and bottom central stabilizing plates as aerodynamic countermeasures. Numerical results indicate that the large-scale vortex under the deck separates into smaller vortices, resulting in the disappearance of the von Kármán vortex street in the wake zone because the countermeasures effectively suppress the VIVs. Furthermore, a full-bridge aeroelastic model with a scale of 1/100 was constructed and tested to evaluate the wind resistance performance and validate the effectiveness of the proposed countermeasures.

• Journal of Trauma and Injury
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• v.37 no.1
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• pp.79-82
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• 2024

The potential for traumatic brain injury resulting from falling coconuts is frequently overlooked. These incidents can cause focal lesions in the form of brain hemorrhage. Corpus callosum hemorrhage due to blunt trauma from a falling object is rare and typically associated with poor prognosis. The purpose of this report is to detail a case of corpus callosum hemorrhage caused by a coconut fall and to discuss the conservative management approach employed. We report the case of a 54-year-old woman who was admitted to the hospital with symptoms of unconsciousness, headache, and expressive aphasia after being struck by a falling coconut. Notably, hemorrhage was detected within the body of the corpus callosum, as revealed by imaging findings. The patient received intensive monitoring and treatment in the intensive care unit, including oxygen therapy, saline infusion, an osmotic diuretic, analgesics, and medication to prevent stress ulcers. The patient demonstrated marked clinical improvement while undergoing conservative treatment. Despite the typically unfavorable prognosis of these rare injuries, our patient exhibited meaningful clinical improvement with conservative treatment. Timely diagnosis and appropriate interventions were crucial in managing the patient's condition. This report emphasizes the importance of considering traumatic brain injury caused by falling coconuts and highlights the need for further research and awareness in this area.