• The Journal of the Korean dental association
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• v.13 no.1
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• pp.33-36
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• 1975

To determine the dental arch length and width in Korean yaung adults, various points (shown on Fig 1) were measured by means of Boley gauge on the 124 plaster models which obtained from 2 young men. The measurements value were as follows: A : 36.10㎜ a : 25.53㎜ B : 33.35㎜ b : 28.20㎜ C : 39.80㎜ c : 33.07㎜ D : 43.36㎜ d : 36.36㎜ E : 44.80㎜ e : 39.12㎜ F : 49.11㎜ f : 42.48㎜ G : 59.98㎜ g : 44.92㎜ H : 62.22㎜ h : 57.85㎜ I : 52.66㎜ i : 49.91㎜

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.6
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• pp.332-338
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• 2023

Objectives: This study aimed to compare the effectiveness of a hybrid arch bar (hAB) with the conventional Erich arch bar (EAB) for the management of jaw fractures, focusing on their use for temporary fixation in patients undergoing open reduction and internal fixation (ORIF). Materials and Methods: Patients presenting with maxillary and mandibular fractures at our institution were included in this prospective, comparative study. Placement time and ease of occlusal reproducibility were recorded intraoperatively for Group A (hAB patients) and Group B (EAB patients). The primary outcome was comparison of the postoperative stability of the two arch bars. Postoperative measurements also included mucosal overgrowth, screw loosening or wire retightening, and replacement rates. The data were tabulated and computed with a P<0.05 considered statistically significant. Results: The study included 41 patients. A statistically significant difference was observed in postoperative stability scores (3) between Group A and Group B (85.0% vs 9.5%, P=0.001). The mean placement time in Group A (23.3 minutes) significantly differed from that in Group B (86.4 minutes) (P<0.001). The ease of intraoperative occlusion was not different between the two groups (P=0.413). Mucosal overgrowth was observed in 75.0% of patients (15 of 20) in Group A. Conclusion: The hAB was superior to EAB in clinical efficiency, maxillomandibular fixation time reduction, stability, versatility, and safety. Despite temporary mucosal overgrowth, the benefits of hAB outweigh the disadvantages. The choice between hAB and EAB should be based on specific clinical requirements.

• Computers and Concrete
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• v.22 no.1
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• pp.101-116
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• 2018

As one of the most important engineering structures, arch dams are huge constructions built with human hands and have strategical importance. Because of the fact that long construction duration, water supply, financial reasons, major loss of life and material since failure etc., the design of arch dams is very important problem and should be done by expert engineers to determine the structural behavior more accurately. Finite element analyses and non-destructive experimental measurements can be used to investigate the structural response, but there are some difficulties such as spending a long time while modelling, analysis and in-situ testing. Therefore, it is more useful to conduct the research on the laboratory conditions and to transform the obtained results into real constructions. Within the scope of this study, it is aimed to determine the structural behavior of arch dams considering experimentally validated prototype laboratory model using similitude and scaling laws. Type-1 arch dam, which is one of five arch dam types suggested at the "Arch Dams" Symposium in England in 1968 is selected as reference prototype model. The dam is built considering dam-reservoir-foundation interaction and ambient vibration tests are performed to validate the finite element results such as dynamic characteristics, displacements, principal stresses and strains. These results are considered as reference parameters and used to determine the real arch dam response with different scales factors such as 335, 400, 416.67 and 450. These values are selected by considering previously examined dam projects. Arch heights are calculated as 201 m, 240 m, 250 m and 270 m, respectively. The structural response is investigated between the model and prototype by using similarity requirements, field equations, scaling laws etc. To validate these results, finite element models are enlarged in the same scales and analyses are repeated to obtain the dynamic characteristics, displacements, principal stresses and strains. At the end of the study, it is seen that there is a good agreement between all results obtained by similarity requirements with scaling laws and enlarged finite element models.

• Journal of Korean Neurosurgical Society
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• v.58 no.6
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• pp.528-533
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• 2015

Objective : We sought to examine anatomic variations of the atlas and the clinical significance of these variations. Methods : We retrospectively reviewed 1029 cervical 3-dimensional (3D) CT images. Cervical 3D CT was performed between November 2011 and August 2014. Arcuate foramina were classified as partial or complete and left and/or right. Occipitalization of the atlas was classified in accordance with criteria specified by Mudaliar et al. Posterior arch defects of the atlas were classified in accordance with criteria specified by Currarino et al. Results : One hundred and eight vertebrae (108/1029, 10.5%) showed an arcuate foramen. Bilateral arcuate foramina were present in 41 of these vertebrae and the remaining 67 arcuate foramina were unilateral (right 31, left 36). Right-side arcuate foramina were partial on 18 sides and complete on 54 sides. Left-side arcuate foramina were partial on 24 sides and complete on 53 sides. One case of atlas assimilation was found. Twelve patients (12/1029, 1.17%) had a defect of the atlantal posterior arch. Nine of these patients (9/1029, 0.87%) had a type A posterior arch defect. We also identified one type B, one type D, and one type E defect. Conclusion : Preoperative diagnosis of occipitalization of the atlas and arcuate foramina using 3D CT is of paramount importance in avoiding neurovascular injury during surgery. It is important to be aware of posterior arch defects of the atlas because they may be misdiagnosed as a fracture.

• Journal of Chest Surgery
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• v.30 no.1
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• pp.83-87
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• 1997

Taussig-Bing anomaly is infrequently associated with interrupted aortic arch and size discrepancy of great arteries makes it difficult to undergo arch reconstruction and arterial switch operation. A 20-day old male infant was admitted with the diagnosis of Taussig-Bing anomaly with type B Interrupted aortic arch. Multi-organ failure, due to the diminution of ductal flow, was stabilized after 3 weeks of prostaglandin El and controlled ventilatory support. The surgical correction consisted of VSD closure, arterial swtich and extended aortic arch reconstruction. The marked disparity between the hypoplastic ascending aorta and the dilated main pulmonary artery was overcome by constructing distal neoaorta using both native ascending and descending aortic tissue. The patient was extubated on postoperative 2nd day Postoperative catheterization showed no left ventricular outflow obstruction, no intracardiac shunt, and no incompetence of neoaortic valve.

• Steel and Composite Structures
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• v.25 no.2
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• pp.231-244
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• 2017

This paper presents the structural identification of an arch dam model for the damaged, repaired and strengthened conditions under different water levels. For this aim, an arch dam-reservoir-foundation model has been constructed. Ambient vibration tests have been performed on the damaged, repaired and strengthened dam models for the empty reservoir (0 cm), 10 cm, 20 cm, 30 cm, 40 cm, 50 cm and full reservoir (60 cm) water levels to illustrate the effects of water levels on the dynamics characteristics. Enhanced Frequency Domain Decomposition Method in the frequency domain has been used to extract the dynamic characteristics. The dynamic characteristics obtained from the damaged, repaired and strengthened dam models show that the natural frequencies and damping ratios are considerably affected from the varying water level. The maximum differences between the frequencies for the empty and full reservoir are obtained as 16%, 33%, and 25% for damaged, repaired and strengthened model respectively. Mode shapes obtained from the all models are not affected by the increasing water level. Also, after the repairing and strengthening implementations, the natural frequencies of the arch dam model increase significantly. After strengthening, between 46-92% and 43-62% recovery in the frequencies are calculated for empty and full reservoir respectively. Apparently, after strengthening implementation, the mode shapes obtained are more acceptable and distinctive compared to those for the damaged model.

• The korean journal of orthodontics
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• v.32 no.2 s.91
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• pp.117-127
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• 2002

The purpose of this study was to compare the arch width of the hyperdivergent group with that of the neutral group in Class III malocclusion based on the vertical patterns and to compare the arch width of Class III neutral group With that of normal occlusion group based on sagittal patterns. The subjects consisted of 118 pairs of studty casts, divided into three groups , 37 Class III hyperdivergent group(18 males and 19 females, SN-Mn plane angle>39.5$^{\circ}$), 40 Class III neutral group(20 males and 20 females, SN-Mn plane angle : 32 ${\pm}$ 2.5$^{\circ}$) and 41 Class I normal occlusion group(20 males and 21 females). The intercanine, interpremolar, and intermolar width of the maxillary and mandibular study casts were measured, then the ratios of dental width to basal width and mandibular width to maxillary width were obtained. Basal arch width and dental arch width were measured to obtain the pure basal arch relation in transverse plane as ruled out the transverse dental compensation. The results were as follows 1. There were no significant differences in any ratios between Class III hyperdivergent group and Class III neutral group as different vertical pattern. 2. As the ratios of dental arch width to basal arch width between normal occlusion group and Class III neutral group were compared, the maxillary teeth flared buccally to the basal bone, and the mandibular teeth tilted lingually to the basal bone in Class III neutral group. 3. The ratios of mandibular arch width to maxillary arch width in basal arch level were significantly different in all regions. Maxillary basal arch width of Class III neutral group was narrower than that of normal occlusion group. 4. The ratios of mandibular arch width to maxillary arch width in teeth level were not significantly different between normal occlusion group and Class III neutral group. In spite of discrepancies of maxillary and mandibular basal arch width, the dental arch width of Class III malocclusion group compensated very well. At the presurgical orthodontic treatment in clinic, it would not be desirable to decompensate for compensated dental arch width too much, for obtaining an appropriate arch compatibility and good results for orthognathic surgery.

• Korean Journal of Applied Biomechanics
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• v.25 no.4
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• pp.489-498
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• 2015

Objective : The purpose of this study was to analyze the effects of the windlass mechanism in trail-walking shoe prototypes that can effectively support arches. A study of these effects should help with the development of a first-rate trail-walking shoe development guide for the distribution of quality information to consumers. Methods : The subjects were ten adult males who volunteered to participate in the study. Shoes from three companies, which will be referred to as Company S (Type A), Company M (Type B), and Company P (Type C), were selected for the experiment. The subjects wore these shoes and walked at a speed of 4.2 km/h, and as they tested each shoe, the contact area, maximum pressure average, and surface force were all measured. Results : Shoe Type A showed a contact area of $148.78{\pm}4.31cm^2$, Type B showed an area of $145.74{\pm}4.1cm^2$, and Type C showed an area of $143.37{\pm}4.57cm^2$ (p<.01). Shoe Type A demonstrated a maximum average pressure of $80.80{\pm}9.92kPa$, Type B an average of $85.72{\pm}11.01kPa$, and Type C an average of $89.12{\pm}10.88bkPa$ (p<.05). Shoe Type A showed a ground reaction force of $1.13{\pm}0.06%BW$, Type B a force of $1.16{\pm}0.04%BW$, and Type C a force of $1.16{\pm}0.03%BW$ (p<.05). Conclusion : The Type A trail-walking shoe, which was designed with a wide arch from the center of the forefoot to the front of the rearfoot showed excellent performance, however, more development and analysis of the windlass mechanism for a variety of arch structures is still necessary.

• Journal of Industrial Technology
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• v.22 no.B
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• pp.199-209
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• 2002

This research is experimental thesis to prepare the structural safety of the upper bridge for support type on tunnel and the effect of settlement. Unit weight test and uni-axial compression test have been performed to simulate the physical property of foundation on the tunnel. Tunnel model of slip form type for centrifuge model has been developed to performed the tunnel excavation while field stress is activated. And the support type of tunnel such as umbrella arch method and large diameter steel pipe reinforce method has been tested for the centrifuge model. After the analysis of experiment, results show that internal displacement of large diameter steel pipe reinforce method is smaller than that of the umbrella arch method.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.223-226
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• 2007

In current specification, modification factor(B) for web-tapered beam is used to account for the stress gradient and the restraining effect for adjacent spans. However, because these effects are considered together in modification factor, this paper revaluate the accuracy of the modification factor used in current specification. Also this paper investigate the flexural torsional buckling strength of laterally fixed thin-walled arch with doubly symmetric section using the analytical and numerical method. From this investigate the concept of effective length to consider the out-of-plane boundary condition for straight column or beam is not applicate for the flexural-torsional buckling of laterally fixed arches.