• Journal of the Korean Institute of Rural Architecture
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• v.23 no.1
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• pp.1-8
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• 2021

In this study, a real-sized experimental equipment (pilot plant) was built at the site based on the preliminary research data to develop a movable separator for the mixed construction waste that can be implemented in agricultural areas to review its feasibility through the evaluation of its separation efficiency by waste types. The final construction of the movable separator and experimental results of the separation efficiency are summarized as follows. 1) The separation performance according to the blade type was the best for the combustible wastes either with 26 numbers of L-type blades and 32 numbers of pin type blades. As far as combination of blade types, when the L-type and pin-type were combined, the best separation efficiency was achieved. 2) The separation efficiency for waste wood by the conveyor type and angle of inclination (slope) of the trommel was the best when the conveyor had ribs of seagull shape with the angle of inclination 45°. 3) The separation efficiencies by process showed that 65.9% was separated as inorganic demolition wastes, 18.2% as waste woods, and 16.0% as combustible wastes at conveyor speed of 2-3 rpm, and the error rate was the least from the waste types generated in the dismantle site.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.567-582
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• 2022

In the present study, a series of physical experiments and numerical simulations were conducted to investigate the effects of mode I and mixed-mode I/II cracks on the fracture modes and stability of roadway tunnel models. The experiments and simulations incorporated different inclination angle flaws under both static and dynamic loads. The quasi-static and dynamic testing were conducted by using an electro-hydraulic servo control device and drop weight impact system (DWIS), and the failure process was simulated by using rock failure process analysis (RFPA) and AUTODYN software. The stress intensity factor was also calculated to evaluate the stability of the flawed roadway tunnel models by using ABAQUS software. According to comparisons between the test and numerical results, it is observed that for flawed roadways with a single radical crack and inclination angle of 45°, the static and dynamic stability are the lowest relative to other angles of fractured rock masses. For mixed-mode I/II cracks in flawed roadway tunnel models under dynamic loading, a wing crack is produced and the pre-existing cracks increase the stress concentration factor in the right part of the specimen, but this factor will not be larger than the maximum principal stress region in the roadway tunnel models. Additionally, damage to the sidewalls will be involved in the flawed roadway tunnel models under static loads.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.4
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• pp.469-482
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• 2023

This study aimed to investigate the treatment options for the delayed eruption of mandibular premolars and identify the predictors of spontaneous eruption using panoramic radiography. The prevalence of delayed mandibular premolar eruption in this retrospective analysis, comprising 254 patients (aged 9 - 15 years), was 5.19%, with no significant difference based on gender. The mandibular second premolars were most affected (4.39%) compared to the first premolars (0.76%). No significant difference in prevalence was observed between the left and right sides. Among the treated mandibular premolars, primary molar-related lesions were identified as the leading cause (7.85%) of delayed tooth eruption. The treatment duration varied based on the Nolla stage, eruption stage, and treatment method. Teeth with Nolla stage 7 or lower had a treatment duration of 22.89 ± 11.96 months, whereas those with stage 8 or higher had a 15.02 ± 6.34 month duration. The deeper the tooth was located in the bone, the longer the treatment period became. The treatment duration varied depending on the treatment method, and statistically, there was no significant difference. The treatment durations for affected mandibular premolars increased with the depth of impaction angle of inclination. In this study, the treatment duration for delayed eruptions varied depending on the Nolla stage, eruption stage, and treatment method. Variations in the impaction depth and inclination angle across various treatment approaches, as explored in this study, might offer valuable insights into the selection of the most suitable management options for delayed tooth eruptions.

• Journal of Oral Medicine and Pain
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• v.24 no.2
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• pp.189-206
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• 1999

This study was performed to investigate the factors affecting muscle activity and cephalometric variables according to change of head postures. For this study, 150 patients with temporomandibular disorders and 80 dental students without any signs and symptoms of temporomandibular disorders were selected as the patients group and as the normal group, respectively. Head position to body-midline in frontal plane and upper quarter posture to body plumb line in sagittal plane were observed clinically and electromyographic(EMG) activity of anterior temporalis, masseter, sternocleidomastoideus, and trapezius on clenching were recorded with $BioEMG^{(R)}$ in four head postures, which were natural head posture(NHP), forward head posture(FHP), $20^{\circ}$ upward head posture(UHP), and $20^{\circ}$ downward head posture(DHP). Cephaloradiographs were also taken in the same head postures as in EMG taking, but that was taken only in NHP for the patient group. Cephalometric variables measured were SN angle, CVT angle, atlas inclination angle, occlusal plane angle, Me-C2 angle, pharyngeal width, occiput~axis distance, area of pharyngeal space, and cervical curvature. The data were analyzed by SAS statistical program. The results of this study were as follows : 1. Between the patient and the normal group, there were significant difference in distance from plumb line to acromion, eye-tragus angle, electromyographic activity of the four muscles, and cephalometric variables of linear measurement. 2. There was no consistent pattern of correlation between upper quarter posture, EMG activity and cephalometric variables in any case without relation to cervical curvature and head position in frontal plane. 3. Sternocleidomastoid muscle only showed variation of electromyographic activty with changes of head postures, but all the muscles did show correlation with head postures. 4. All the cephalometric variables measured in this study showed difference of mean value by head posture, and CVT angle, pharyngeal width, occiput-atlas distance, and area of pharyngeal space showed correlation between these variables with change from NHP to FHP, and from NHP to UHP.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.10
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• pp.1963-1970
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• 1992

An oscillatory motion of the natural convection in a two dimensional, partially divided square enclosure heated from below, and fitted with a partition is investigated numerically. The enclosure was composed of the lower hot and the upper cold horizontal walls and the adiabatic vertical walls, and a partition was situated perpendicularly at the mid-height of the one vertical insulated wall. The governing equations are solved by using the finite element method with Galerkin method. The computations were performed with the variation of the length and the thermal conductivity of the partition, and Rayleigh number based on the temperature difference between horizontal walls and the enclosure height with water(Pr=4.95). also, the effect of the inclination angles was studied for the transition to the oscillating flow. As the results, it was found that the intensity and frequency of oscillatory motion were affected significantly by the Rayleigh number and the length of partition. The effect of oscillatory motion was weaken with the increase of the thermal conductivity of partition. The inclination angle for the transition was raised with the increase of Rayleigh number and the length of partition.

• Journal of Korean Foot and Ankle Society
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• v.8 no.2
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• pp.191-194
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• 2004

Purpose: Anatomic configuration of the ankle joint is useful information during various ankle procedures. This study was prospectively designed to investigate the sagittal inclination pattern of the ankle joint. Materials and Methods: Lateral standing ankle radiographs from one-hundred people (age: $17{\sim}68$, M:F=45:55) and magnetic resonance (MR) sagittal ankle images from twenty-four people (age: $16{\sim}65$, M:F=14:10) were studied. Post-traumatic, arthritic, or grossly deformed ankles at any reason were excluded. The posterior inclination angle (PIA) of the distal tibia was measured and compared between the lateral and the medial segment. Results: On plain radiographic data, the average PIA of the distal tibia was $6.14^{\circ}{\pm}3.56^{\circ}$ (range $0^{\circ}$ to $14^{\circ}$) in the lateral segment and $13.16^{\circ}{\pm}3.05^{\circ}$ (range $6^{\circ}$ to $22^{\circ}$) in the medial segment. On MR imaging data, the average PIA of the distal tibia was $5.08^{\circ}{\pm}4.26^{\circ}$ (range $1^{\circ}$ to $10^{\circ})$ in the lateral segment and $10.16^{\circ}{\pm}4.87^{\circ}$(range $5^{\circ}$ to $17^{\circ}$) in the medial segment. The PIA between two segments was significantly different. Conclusion: The sagittal configuration of the medial area ankle joint and the lateral area ankle joint has difference in the degree of posterior inclination and shape of curvature.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.4
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• pp.512-519
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• 2015

A historical tragic disaster happened by capsizing the passenger ship Sewol at South Western Sea of Korea in 16, April 2014. The ship which left Incheon harbour to bound for Jeju port passed Maengol strait and reached to approach of Byung Pung island, and then capsized and sank with a sudden inclination to the portside in the mean time of starboard the helm. In this time, the ship which has very poor stability without sufficient ballast waters and with over loading cargo listed port side caused by the centrifugal force acting to the outside of turning. A lot of cargoes not fastened moved to the port side consequently, and the ship came to beam end to capsize and sank in the end. No crews including especially captain would offer their own duties in a such extremely urgent time, as a result, enormous number of victims broke out including a lot of student. In this report, author carried out some calculation on the factors which influenced on the stability of the ship, i.e. the ship's speed, the rudder angle, the weight of cargoes and distance of movement, the surface effect of liquid in the tank. We found out that the most causes of capsize were the poor stability with heavy cargoes and insufficient amount of ballast water against the rule, and the cargoes unfastened moved one side to add the inclination as well. Above all, the owner be blamable because of the illegally operating the ship without keeping the rule.

• The korean journal of orthodontics
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• v.45 no.5
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• pp.245-252
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• 2015

Objective: To assess the labial and lingual alveolar bone thickness in adults with maxillary central incisors of different inclination by cone-beam computed tomography (CBCT). Methods: Ninety maxillary central incisors from 45 patients were divided into three groups based on the maxillary central incisors to palatal plane angle; lingual-inclined, normal, and labial-inclined. Reformatted CBCT images were used to measure the labial and lingual alveolar bone thickness (ABT) at intervals corresponding to every 1/10 of the root length. The sum of labial ABT and lingual ABT at the level of the root apex was used to calculate the total ABT (TABT). The number of teeth exhibiting alveolar fenestration and dehiscence in each group was also tallied. One-way analysis of variance and Tukey's honestly significant difference test were applied for statistical analysis. Results: The labial ABT and TABT values at the root apex in the lingual-inclined group were significantly lower than in the other groups (p < 0.05). Lingual and labial ABT values were very low at the cervical level in the lingual-inclined and normal groups. There was a higher prevalence of alveolar fenestration in the lingual-inclined group. Conclusions: Lingual-inclined maxillary central incisors have less bone support at the level of the root apex and a greater frequency of alveolar bone defects than normal maxillary central incisors. The bone plate at the marginal level is also very thin.

• The korean journal of orthodontics
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• v.44 no.2
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• pp.77-87
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• 2014

Objectives: This study was designed to define the Korean norm values for the Ricketts analysis. Methods: In this longitudinal study, lateral cephalograms of 31 subjects with normal occlusion were taken biennially from ages 9-19 years. Cephalometric measurements were performed. Parameters for which the 10-year change did not exceed one standard deviation were defined as unchanged. The means and standard deviations for the measured parameters were determined for each age group. Results: No significant changes in growth were observed in the molar relationship, incisor overjet, incisor overbite, mandibular incisor extrusion, interincisor angle, lower incisor tip (B1) to A point-Pogonion (A-PO) plane, upper incisor tip (A1) to A-PO plane, B1 inclination to A-PO, A1 inclination to A-PO, B1 inclination to Frankfurt plane (FH), convexity, lower facial height, facial axis, maxillary depth, maxillary height, palatal plane to FH, cranial deflection, ramus Xi position, or porion location. Continual changes over the 10 years of growth were observed in the maxillary first molar distal position to pterygoid true vertical plane, facial depth, mandibular plane to FH, anterior cranial length, mandibular arc, and corpus length. Conclusions: Clinicians can apply the Korean norms at age 9 as determined in this study when using the Ricketts analysis. The patient's age at the beginning of treatment and their sex should be taken into consideration when drawing visual treatment objectives.

• The korean journal of orthodontics
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• v.50 no.4
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• pp.229-237
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• 2020

Objective: To evaluate the construction reproducibility of a composite tooth model (CTM) composed of an intraoral-scanned crown and a cone-beam computed tomography (CBCT)-scanned root. Methods: The study assessed 240 teeth (30 central incisors, 30 canines, 30 second premolars, and 30 first molars in the maxillary and mandibular arches) from 15 young adult patients whose pre-treatment intraoral scan and CBCT were available. Examiner-Reference (3 years' experience in CTM construction) and Examiners-A and Examiner-B (no experience) constructed the individual CTMs independently by performing the following steps: image acquisition and processing into a three-dimensional model, integration of intraoral-scanned crowns and CBCT-scanned teeth, and replacement of the CBCT-scanned crown with the intraoral-scanned crown. The tooth axis angle in terms of mesiodistal angulation and buccolingual inclination of the CTMs constructed by the three examiners were measured. To assess the construction reproducibility of CTMs, intraclass correlation coefficient (ICC) assessments were performed. Results: The ICC values of mesiodistal angulation and buccolingual inclination among the 3 examiners showed excellent agreement (0.950-0.992 and 0.965-0.993; 0.976-0.994 and 0.973-0.995 in the maxillary and mandibular arches, respectively). Conclusions: The CTM showed excellent construction reproducibility in mesiodistal angulation and buccolingual inclination regardless of the construction skill and experience levels of the examiners.