• Journal of the Korean Society of Marine Environment & Safety
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• v.7 no.3
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• pp.75-84
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• 2001

Ultrasonic vibrator is an equipment which atomizes and homogenizes the oils by breaking the oil particles with ultrasonic vibration cavity, and possibly improves the properties. There are various parameters on the effect of ultrasonic irradiation. Especially, this study intended to investigate the matrix structure of sludge oils and the erosion damages for horn disc SS41 according to the variation of the oil temperature and the immersing depth of horn disc. Sludge oils were irradiated with ultrasonic vibration and then observed the aspects of the change of oil particles. From these, the recycling feasibility of sludge oil for useable oil to be burnt was determined. The erosion damages for horn disc SS41 were examined with weight loss, weight loss rate and the irradiation time to max. erosion rate. These data will be useful to the development of ultrasonic breaking systems to recycle sludge oil and to consider a countermeasure for the prevention of erosion damages.

• Journal of Species Research
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• v.2 no.1
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• pp.1-6
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• 2013

Conchodytes nipponensis (De Haan, 1844), a caridean shrimp living in the mantle cavity of a pen shell (Atrina pectinata) is reported for the first time from Korea. It was collected from a depth of 15 m depth. Its morphology is described and illustrated, and a color image of a living specimen is provided. This is at the same time the first record of the genus Conchodytes, and the first record of a bivalve mollucs associated shrimp, from Korea.

• International Journal of Ocean System Engineering
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• v.2 no.2
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• pp.71-81
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• 2012

Several methods have been proposed to control the sedimentation process. These include catchment management, flushing, sluicing, density current venting, and dredging. Flushing is used to erode previously deposited sediments. In pressurized flushing, the sediment in the vicinity of the outlet openings is scoured and a funnel shaped crater is created. In this study, the effect of localized vibrations in the sediment layers on the dimensions of the flushing cone was investigated experimentally. For this purpose, experiments were carried out with two bottom outlet diameters, five discharge releases for each desired water depth, and one water depth above the center of the bottom outlets. The results indicate that the volume and dimensions of the flushing cone are strongly affected by localized vibrations.

• Restorative Dentistry and Endodontics
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• v.13 no.2
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• pp.337-348
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• 1988

The purpose of this study was to examine the fracture strength and characteristics of teeth with MOD cavity preparation. Freshly extracted sound maxillary premolars were cleaned and stored in normal saline solution $37^{\circ}C$ for 72 hours before experiments. The roots of teeth were embedded in a self-curing resin, and the exposed crown were maintained in a vertical position by a modelling wax in a brass ring. The MOD cavities were prepared with No. 57 carbide bur under high speed to a depth of 2.0mm and a width of 2.0mm(Fig.1). All the prepared teeth specimens were divided into 7 groups according to the mode of cavity form and restorative materials (Table 1, 2): Group I, unpreapred, intact teeth as control Group II, prepared cavity without restoration Group III, prepared teeth restored with amalgam Group IV, prepared teeth restored with composite resin (P-10) Group V, prepared teeth with beveled enamel margins restored with composite resin (P-10) Group VI, prepared teeth restored with light-cured composite resin (P-30) Group VII, prepard teeth with beveled enamel margins restored with light-cured composite resin (P-30) After placement of restorations, all of the specimens were stored in water at $37^{\circ}C$ for 72 hours before testing. All of the specimens were tested on the Instron Universal Testing machine (No. 6025) in order to evaluate the strength of fracture. One metal ball 5.0mm in diameter contacting the specimens parallel to the occlusal surface was used to in this study (Fig. 1). The fracture characteristics of the specimens were examined with naked eye and in the scanning electron microscope (JSM-20). The results obtained from this study were as follows: 1. The mean fracture strength was the highest in group VI and that in group II was the lowest. 2. The progress of crack of teeth propagated into the pulp cavity. 3. In case of the group of the restored teeth, the crack occurred to be accompanied with cuspal fracture. 4. The crack of restored teeth was initiated along the pulpo-axial line angle of the cavity.

• Restorative Dentistry and Endodontics
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• v.31 no.4
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• pp.257-262
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• 2006

The aims of the study were to evaluate the effect of epinephrine-containing local anesthetics on pulpal blood flow (PBF) and to investigate its effect on cavity preparation-induced PBF change. PBF was recorded using a laser Doppler flowmeter (Perimed Co., Sweden) from canines of nine cats under general anesthesia before and after injection of local anesthetics and after cavity preparation. 2% lidocaine hydrochloride with 1 : 100,000 epinephrine was administered by local infiltration given apical to the mandibular canine at the vestibular area and the same volume of isotonic saline was injected on the contralateral tooth as a control. A round carbide bur was operated at slow speed with isotonic saline flushing to grind spherical cavities with increasing depth through the enamel and into the dentin on both teeth. The obtained data was analyzed with paired t-test. Cavity preparation caused significant increase of PBF (n = 9, p < 0.05). Local infiltration of lidocaine with epinephrine resulted in decreases of PBF (n = 9, p < 0.05), whereas there was no significant change of PBF with the physiologic saline as a control. Cavity preparation on tooth anesthetized with lidocaine with epinephrine caused significantly less increase of PBF than in control tooth (p < 0.05). Therefore, the result of the present study demonstrates that local infiltration of 2% lidocaine with 1 : 100,000 epinephrine effectively reduces PBF increase caused by cavity preparation.

• Journal of Radiation Protection and Research
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• v.15 no.2
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• pp.57-65
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• 1990

Newly developed LiF(Mg, Cu, Na, Si) thermoluminescence phosphors sealed in a plastic capsules (32mm dia., 0.9mm wall thickness) were used for in-phantom dosimetry of $^{60}Co$ $\gamma$-irradiation. The absorbed doses in water were determined by applying the general cavity theory to the absorbed dose in TLD cavity, which was computed from exposure. The absorbed doses at various sites in the water-phantom were measured by LiF(Mg, Cu, Na, Si) TLD and compared with doses obtained by the ionization method. Both results were consistent within the experimental fluctuation$({\pm}3%)$ Central axis percentage depth doses and phantom-air ratios measured by LiF(Mg. Cu, Na, Si) TLD showed good agreement with the published values[Br. J. Radiology, Suppl. 17(1983)].

• Archives of Craniofacial Surgery
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• v.24 no.5
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• pp.211-217
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• 2023

Background: Oral cavity cancers, the second most common type in India, are responsible for 10% of the overall cancer burden. With a recurrence rate of 30% to 40% and a 5-year survival rate of 50%, these malignancies account for substantial morbidity and mortality. Despite advances in treatment modalities, survival rates following treatment completion have not improved significantly. The present study aimed to establish specific epidemiological and pathological factors responsible for recurrence after treatment completion in buccal mucosa cancers. Methods: A retrospective analysis of the data of 116 patients treated for biopsy-proven cancers of the buccal mucosa was undertaken 1 year after treatment completion. Factors such as age, sex, education, lymphovascular invasion, extranodal extension (ENE), perineural invasion, depth of invasion, and pathological margin status were compared between patients who presented with recurrence and those who did not. Statistical significance was set at p< 0.05. Results: Of the 116 patients, 40 (34.5%) developed a recurrent disease within 1 year. The mean age of the study population was 43.3 years, and males constituted 91.4% of the included patients. Ipsilateral buccal mucosa was the commonest site of disease recurrence. Neck node metastasis, ENE, and margins of resection < 5 mm were significantly related to the recurrence of disease. However, surprisingly, lymphovascular invasion, perineural invasion, and depth of invasion > 10 mm did not show statistically significant associations. Conclusion: Neck node metastasis, ENE, and margins of resection < 5 mm were the histopathological factors associated with recurrence in cancers of the buccal mucosa.

• Design & Manufacturing
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• v.18 no.3
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• pp.71-80
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• 2024

Sink marks are a common defect that occurs due to differences in shrinkage in areas with significant thickness variations in injection-molded parts. In this paper, we investigated the reduction of sink marks and the improvement of gas venting in injection molding processes using External Gas Injection (EGI). A mold was designed with considerations for EGI core pins, O-ring grooves to prevent gas leakage, and ejector-pin sealing. The sink marks were then examined through a series of experiments. When the delay time for injecting compressed air was set to 2.2 seconds, the depth of the sink marks was minimized. However, when the delay time was either too short or too long, the depth of the sink marks increased. There was almost no difference in the depth of the sink marks at discharge pressures of 30 and 50 bar of compressed air, but the sink marks were significantly reduced at a discharge pressure of 70 bar. Under the conditions of a 2.2-second delay time and a supply pressure of 70 bar, the smallest depth, 0.594 ㎛, was observed when the supply time was between 6 and 7 seconds. This represents a reduction of approximately 94% compared to the sink mark depth of 10.078 ㎛ observed with conventional injection molding. To verify the gas venting effect of compressed air injection, an experiment was conducted using non-dried PC. The silver streaks that appeared on the exterior of the molded part were completely eliminated when the air supply pressure was set to 20 bar. This indicates that by injecting compressed air into the mold cavity before injecting the resin, the appearance quality of the injection-molded part can be improved without the need to dry the resin in advance.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.3
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• pp.253-258
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• 2019

A female English bulldog was gave birth two neonates by cesarean section on the sixty one days after mating, but both neonates were died soon after birth. The bodies of neonates were diagnosed using radiography, ultrasonography, computed tomography and necropsy immediately after death. Both neonates had caudal regression syndrome, butterfly vertebra, hydrocephalus, umbilical hernia, cleft palate and bow-legged hind-limb. At necropsy, neonates had mild fetal anasarca, cleft lip and the skull was remained non-union. At thoracic cavity, only three ribs and thoracic spines were existed and patent ductus arteriosus was found. At abnormal cavity, the renal ectopia was found with abnormal morphology. In the present case, those English bulldog neonates with multiple congenital malformation syndromes seriously suffered vertebral column anomalies and that may induced by neural tube defects in during embryonic period. To prevent congenital malformation occurring in English bulldog, further in depth studies are needed for the breed specific genetic diversity and for the reason of behind genetic abnormality in these breed.

• Journal of computational fluids engineering
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• v.17 no.1
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• pp.78-85
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• 2012

Cavitation causes a great deal of noise, damage to components, vibrations, and a loss of efficiency in devices, such as propellers, pump impellers, nozzles, injectors, torpedoes, etc., Thus, cavitating flow simulation is of practical importance for many engineering systems. In this study, a two-phase flow solver based on the homogeneous mixture model has been developed. The flow characteristics around an axisymmetric cylinder were calculated and then validated by comparing with the experimental results in the cavitation water tunnel at the Korea Ocean Research & Development Institute. The results show that this solver is highly suitable for simulating the cavitating flows. After the code validation, the cavity length with changes of water depth, angle of attack and velocity were obtained.. Cavitation inception was also calculated for various operational conditions.