• PNF and Movement
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• 제12권4호
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• pp.243-248
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• 2014

Purpose: The transverse abdominis and themultifidus muscle are located in the core. They surround one's trunk and help in body stabilization. Specifically, they control spine articulation to maintain posture and balance. Therefore, weakened deep muscle in the trunk may cause spinal malalignment. This study aims to compare the correlation between the thickness of the transverse abdominis and the multifidus muscle and the spine alignment among college students in their 20s. Methods: This study measured the thickness of the transverse abdominis and the multifidus muscle of 42 healthy college students in their 20s using ultrasonic waves. The thickness of the muscle was measured for the length of the cross-section except for fascia. The thickness of the left and right muscles was measured, and the mean value was calculated. As the thickness of the transverse abdominis can increase because of pressure during exhalation, it was measured at the last moment of exhalation. Spinal alignment was measured by the kyphosis angle, lordosis angle, pelvic tilt, trunk inclination, lateral deviation, trunk imbalance, and surface rotation using Formetric III, which is a three-dimensional imaging equipment. They were measured for three times, and the mean values were calculated. The general characteristics of the subjects were analyzed using descriptive statistics. The correlations between each factor were analyzed using Pearson's correlation analysis. Results: The transverse abdominis showed asignificant correlation with trunk inclination (p<.05). The multifidus muscle showed a significant positive correlation with pelvic tilt and a negative correlation with surface rotation (p<.05). Conclusion: The thickness of transverse abdominis and the multifidus muscle appears to influence spinal alignment. Specifically, the multifidus muscle, which plays an important role on the sagittal plane, influences surface rotation, thus making it an important muscle for scoliosis patients. Therefore, a strengthening training program for the transverse abdominis and the multifidus muscle is necessary according to specific purposes among adults with spinal malalignment.

• 콘크리트학회논문집
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• 제15권5호
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• pp.679-688
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• 2003

종방향 텐던이 경사진 복부에 배치되는 박스 거더의 경우 프리스트레스 힘은 종방향 뿐만 아니라 횡방향 거동에도 영향을 미친다. 본 논문에서는 종방향 프리스트레싱에 의해 유발되는 횡방향 효과를 산정하는 기법을 제안하였다. 박스 거더의 유한요소 정식화 및 종방향 프리스트레싱 해석에 의해 프리스트레스 분포를 산정한 후, 이를 이용하여 횡방향 등가하중을 산정한다. 제안기법에 의한 수치해석결과와 기존의 접판법에 의한 수치해석결과는 유사하며, 이는 본 기법이 합리적임을 나타낸다. 제안기법을 이용하여 박스 거더 슬래브의 횡방향 거동을 분석하였다. 수치분석은 복부경사각, 텐던 편심에 대한 경간 길이비 등과 같은 주요 변수를 통해 수행되었다. 전형적인 단면 조건에서 종방향 프리스트레싱 효과만을 고려할 때, 박스 거더 슬래브의 횡방향 응력은 크지 않은 것으로 나타난다. 그러나, 복부 경사각이 50도 이하로 과도하게 작아지거나 텐던 편심에 대한 경간 길이비가 28이하로 작아지는 경우에는 교량 설계시 횡방향 응력의 크기를 고려할 필요가 있다고 사료된다.

• 대한치과교정학회지
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• 제48권6호
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• pp.357-366
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• 2018

Objective: The purpose of this study was to analyze the transverse dental compensation in reference to the maxillary and mandibular basal bones using cone-beam computed tomography (CBCT) and evaluate the correlations between transverse dental compensation and skeletal asymmetry variables in patients with skeletal Class III malocclusion and facial asymmetry. Methods: Thirty patients with skeletal Class I (control group; 15 men, 15 women) and 30 patients with skeletal Class III with menton deviation (asymmetry group; 16 men, 14 women) were included. Skeletal and dental measurements were acquired from reconstructed CBCT images using OnDemand3D 1.0 software. All measurements were compared between groups and between the deviated and nondeviated sides of the asymmetry group. Correlation coefficients for the association between skeletal and dental measurements were calculated. Results: Differences in the ramus inclination (p < 0.001), maxillary canine and first molar inclinations (p < 0.001), and distances from the canine and first molar cusp tips to the midmaxillary or midmandibular planes (p < 0.01) between the right and left sides were significantly greater in the asymmetry group than in the control group. In the asymmetry group, the ramus inclination difference (p < 0.05) and mandibular canting (p < 0.05) were correlated with the amount of menton deviation. In addition, dental measurements were positively correlated with the amount of menton deviation (p < 0.05). Conclusions: Transverse dental compensation was correlated with the maxillary and mandibular asymmetry patterns. These results would be helpful in understanding the pattern of transverse dental compensation and planning surgical procedure for patients with skeletal Class III malocclusion and facial asymmetry.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권1호
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• pp.21-29
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• 2011

Introduction: To compare the change in frontal ramal inclination (FRI) in laterognathism after orthognathic surgery. Materials and Methods: Twenty four patients (10 men, 14 women; mean age, $22.8{\pm}5.2$ years) with minimal facial canting (${\leq}$ 2 mm) and apparent menton deviation ($5.9{\pm}2.4\;mm$) who had been operated on to correct facial asymmetry and skeletal CIII malocclusion, were selected. On a preoperative posteroanterior (PA) cephalogram, the FRI of the deviated side and non deviated side, L1 deviation amounts and menton deviation amounts were measured. The FRI differences between both sides were compared, and the correlations between the measured deviated elements and the FRI differences were analyzed. On a postoperative PA cephalogram, the shifting amount of L1, shifting amount of L7 and FRI of both sides were measured, and the correlations between the shifting elements and the change in FRI were analyzed. Results: On the preoperative PA cephalogram, the FRI of the non deviated side was significantly greater than those of the deviated side. The differences in FRI, with a menton deviation amount showed a significant correlation. On the postoperative PA cephalogram, the FRI differences between the deviated and non deviated side were decreased significantly and mandibular transverse movement toward central position was noted. The mean shifting amounts of L7 were associated with the amount of change in the deviated side of FRI. Conclusion: Transverse shifting of the mandible through orthognathic surgery decreases the FRI difference, which showed laterognathism, and improves the facial contour.

• 대한치과의사협회지
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• 제55권6호
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• pp.400-410
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• 2017

Approximately 30% of adult patients who want orthodontic treatment have transverse discrepancy with insufficient width of the maxilla. Particularly, in Class III patients requiring orthognathic surgery, the frequency of insufficient width of the maxillary arch related to respiratory problems is high. We report a case of non-surgical maxillary expansion using a Hyrax type expander with an orthognathic surgery, based on the reports that the ratio of non-fused midpalatal suture is not high in adults. A 30 years and 2 months old woman with a long face showed an Angle Class III with a vertical growth pattern. Class III molar and canine relation, anterior edge bite, and mandibular incisor compensatory lingual inclination were observed. The posterior buccal overjet seemed to be appropriate, but I diagnosed that there was a transverse discrepancy, for the following reasons. The inter-canine and inter-molar widths were sufficient but excessive lingual inclination of the mandibular molars was observed when assessing the bucco-lingual inclination based on the center of resistance of the maxillary and mandibular first molar. For this reason, it was expected that intercuspal interference would occur during orthodontic decompensation. Therefore, slow maxillary expansion using Hyrax type expander was performed and 2-jaw rotation surgery was performed to improve aesthetic and occlusion. Adults can also improve width discrepancy by non-surgical methods, which can avoid SARPE requiring additional surgery or segmental surgery lacking stability and predictability.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.955-960
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• 2003

For box girders in which the longitudinal tendon is profiled in the inclined webs. longitudinal prestressing force will induce transverse effects as well as longitudinal ones. In this paper. the method estimating transverse effects induced by longitudinal prestressing is proposed. The transverse effects in the slabs of box girders due to longitudinal prestressing are investigated. Numerical analyses are carried out depending on the parameters such as web inclination and ratio of girder length to tendon eccentricity. Analysis results show that when only prestressing are considered the magnitude of stresses in the slabs of box grder is not so large. However. if the other stresses due to dead and live load et al. are superposed on these stresses. it may be that the longitudinal prestressing effects are significant.

• Structural Engineering and Mechanics
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• 제56권5호
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• pp.797-811
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• 2015

An analytical-computational method along with finite element analysis (FEA) has been employed to analyse the dynamic behaviour of deteriorated structures excited by time- varying mass. The present analysis is focused on the comparative study of a double cracked beam with inclined edge cracks and transverse open cracks subjected to traversing mass. The assumed computational method applied is the fourth order Runge-Kutta method. The analysis of the structure has been carried out at constant transit mass and speed. The response of the structure is determined at different crack depth and crack inclination angles. The influence of the parameters like crack depth and crack inclination angles are investigated on the dynamic behaviour of the structure. The results obtained from the assumed computational method are compared with those of the FEA for validation and found good agreements with FEA.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2016년도 춘계학술대회
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• pp.108-109
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• 2016

선박이 횡경사 되었을 때, 그 발생 원인을 파악하고 적절히 대응하는 것은 매우 중요하다. 특히 최근 발생한 대형 해난사고 중 일부는 항행중 복원력 감소에 의한 횡경사와 관련된 것으로 추정된다. 본 연구에서는 음의 복원력(-GM)에 의한 선박의 횡경사를 실험하고, 그 값을 동일 조건에서의 계산값과 비교하였다. 또한 Loll과 List를 구별하는 것과 Loll 발생 시 대응방안에 대해서 기술하고자 한다.

• Structural Engineering and Mechanics
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• 제73권5호
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• pp.515-527
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• 2020

This paper presents a stress field approach for the shear capacity of stirrup-reinforced concrete beams that explicitly incorporates the contribution of principal tensile stresses in concrete. This formulation represents an extension of the variable strut inclination method adopted in the Eurocode 2. In this model, the stress fields in web concrete consist of principal compressive stresses inclined at an angle θ combined with principal tensile stresses oriented along a direction orthogonal to the former (the latter being typically neglected in other formulations). Three different failure mechanisms are identified, from which the strut inclination angle and the corresponding shear strength are determined through equilibrium principles and the static theorem of limit analysis, similar to the EC-2 approach. It is demonstrated that incorporating the contribution of principal tensile stresses of concrete slightly increases the ultimate inclination angle of the compression struts as well as the shear capacity of reinforced concrete beams. The proposed stress field approach improves the prediction of the shear strength in comparison with the Eurocode 2 model, in terms of both accuracy (mean) and precision (CoV), as demonstrated by a broad comparison with more than 200 published experimental results from the literature.

• 콘크리트학회논문집
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• 제25권1호
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• pp.53-61
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• 2013

코일철근의 직선화 가공성을 향상시키기 위한 마디 형상으로, 철근 축과 마디 사이각 $50^{\circ}$, 마디 윗면 폭(crest width) $0.15d_b$, 마디의 종단면 각도(flank inclination) $55^{\circ}$에 초승달 모양 지압면을 가진 생선뼈 마디(fishbone-shaped transverse rib)를 제안하였다. 이 형상은 직선화 기계의 롤러 홈(groove)과 철근 외부의 접촉면적을 넓혀 마디 손상을 최소화하며 직선도를 향상시키고 가공 생산성을 높일 것으로 기대된다. 제안된 형상을 포함하여 마디 각도가 상이한 3종류의 코일철근(SD500D16 강종)에 대한 부착강도 평가를 위해 겹침이음실험을 실시하였다. 3종의 코일철근은 기존 부착강도 평가식에 따른 예측값보다 평균 10%이상 높은 부착강도를 지닌 것으로 평가되었다. 이것은 코일철근의 상대마디면적비가 기존 평가식 유도에 사용된 실험보다 높기 때문으로 판단된다. 부착강도에 대한 직선철근과 코일철근의 상관계수(correlation coefficient)는 0.94이상 이였으며, 코일철근의 부착성능이 직선철근과 거의 유사함을 알 수 있다. 따라서 실험에 사용된 코일철근의 정착길이와 이음길이 설계에 현행설계기준을 적용하는 것이 타당한 것으로 평가된다.