• Title/Summary/Keyword: cant

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The influence of age on lip-line cant in adults: a cross-sectional study

  • Choi, Sung Hwan;Kim, Jung Suk;Kim, Cheol Soon;Hwang, Chung Ju
    • The korean journal of orthodontics
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    • v.46 no.2
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    • pp.81-86
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    • 2016
  • Objective: The aims of this study were to assess the direction and degree of lip-line cant in Korean adult orthodontic patients and to identify the effects of sex and age on changes in the cant severity. Methods: In this cross-sectional retrospective study, lip-line cant was measured in the frontal photographs of 585 Korean patients (92 men and 493 women) aged 18-48 years. The outcome variables (direction and degree of lip-line cant) were assessed in terms of predictor variables (sex, age, sagittal skeletal relationship, and menton deviation angle). Results: The direction of lip-line cant did not differ according to sex, age, or skeletal classification. Patients had $1.6^{\circ}$ of lip-line cant on average before orthodontic treatment. Middle-aged adults displayed a significant trend toward a lower degree of lip-line cant compared to younger adults (p < 0.01). Multiple linear regression analysis showed that the degree of lip-line cant was weakly negatively correlated with age (p < 0.001). Conclusions: While the direction of lip-line cant did not differ according to the parameters explored here, the degree of cant was correlated with age in adults, independent of menton deviation. Specifically, middle-aged adults tended to display significantly lower degrees of lip-line cant than did younger adults.

A Safety Assessment and Vibration Characteristics of Railway Vehicle Passing Curves (곡선부 통과 차량의 진동특성 및 안전성 평가)

  • Park, Kwang-Soo;Lee, Seung-Il;Lee, Hi-Sung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.10
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    • pp.993-1001
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    • 2007
  • An analysis model has been developed to assess running safety of railway vehicle passing curves. By using ADAMS/Rail, a computer analysis has been conducted by changing various parameters according to the track conditions. Analysis results show as follows: A derailment coefficient of left wheel was increased according to increase of cant at low speed, while it was decreased as increase of cant at high speed. A unload rate of left wheel was also increased according to increase of cant at low speed, while it was decreased as increase of cant at high speed. A wear number of left wheel was increased according to increase of cant at all speed, but only at 35 m/s, it was decreased as increase of cant. A friction coefficient of left wheel was Increased according to increase of cant at all speed, but only at 35 m/s. it was decreased as increase of cant.

Review of Minimum Curve Radius and Cant Range Setting for Mixed Section of Low and High speed Trains in Conventional Railway Line (일반철도의 저속 및 고속열차 혼용구간 최소곡선반경 및 설정캔트범위 검토)

  • Lee, Jae-Hyuk;Kim, Jeong-Hyeok;Park, Young-Gul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.10
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    • pp.345-353
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    • 2020
  • On conventional railway lines, trains with different speeds are operated. Therefore, trains moving on curved sections with cants must accept various ranges of balanced cants, cant deficiency, and cant excess, which is essential for the comfort and safety of train operation. In this study, the correlation between the curve radius, cant, and train speed on a track was analyzed to check the cant range that satisfies the criteria of train types, operation speed, cant deficiency, and cant excess. Also, the range of setting the cant by the curve radius and balanced cant were calculated by a regression analysis of train speed according to the frequency of operation in the case of mixed trains. The results could make it possible to improve the speed of the operation route, reduce the loss of ride quality, reduce the risk of derailing caused by cant deficiency, and minimize the load deflection by excess cant. This will ensure the safety of trains running on curves and improve the efficiency of track maintenance.

A Study on the Running Characteristic by Rail cant variation (레일 캔트 변화에 따른 주행특성에 관한 연구)

  • Eom, Beom-Gyu;Kim, Young-Gyu;Lee, Seung-Il;Lee, Hi-Sung
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1142-1147
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    • 2011
  • The rail cant produces a wider bearing area between the wheel and the rail by moving the wheel-rail contact area away from the gauge towards the centre of the railhead, thus improving the wear pattern of the railhead and wheel treads. It is essential to keep the rail cant within the allowable range to ensure optimum track geometry. Neglecting the rail cant geometrical parameters in a track quality evaluation can cause safety of railway vehicle and serviceability problems. In this paper, we examined the effect of the rail cant in general geometry state of the railway track using VI-Rail and analyzed running safety when the railway vehicle passing through curves depending on change of the rail cant and running speed.

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A Study on the Cant Setting in Railway Curve Section (철도곡선구간에 있어서 캔트 설정에 관한 연구)

  • 이남수
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.11 no.1
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    • pp.1-6
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    • 1993
  • The cant has setted up wrong in a part of railway curve sections, occasionally confusion occur in curve maintenance. In this study, it is suggest effective maintenance method in railway curve section about the radius of curvature, cant successive diminution length, according to the investigation of cant value, compare and analysis with straight decrease in order theory.

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A Study on a Mutual Relation of Cant Deficiency/Rail Wear in Metro Lines (부족캔트량과 레일마모의 상관관계 고찰)

  • 홍철기;양신추;김연태
    • Proceedings of the KSR Conference
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    • 2001.10a
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    • pp.481-487
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    • 2001
  • In this study, the relation between cant deficiency(C') and rail wear in Seoul Metro Line 5 with STEDEF track structure(concrete bed) is studied. As a result, it is found that cant deficiency have a direct influence on rail wear, and under the condition that other negative effects are neglected, the cant deficiency in Metro Lines is demanded to set as little as possible.

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Characterization of facial asymmetry phenotypes in adult patients with skeletal Class III malocclusion using three-dimensional computed tomography and cluster analysis

  • Ha, Sang-Woon;Kim, Su-Jung;Choi, Jin-Young;Baek, Seung-Hak
    • The korean journal of orthodontics
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    • v.52 no.2
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    • pp.85-101
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    • 2022
  • Objective: To classify facial asymmetry (FA) phenotypes in adult patients with skeletal Class III (C-III) malocclusion. Methods: A total of 120 C-III patients who underwent orthognathic surgery (OGS) and whose three-dimensional computed tomography images were taken one month prior to OGS were evaluated. Thirty hard tissue landmarks were identified. After measurement of 22 variables, including cant (°, mm), shift (mm), and yaw (°) of the maxilla, maxillary dentition (Max-dent), mandibular dentition, mandible, and mandibular border (Man-border) and differences in the frontal ramus angle (FRA, °) and ramus height (RH, mm), K-means cluster analysis was conducted using three variables (cant in the Max-dent [mm] and shift [mm] and yaw [°] in the Manborder). Statistical analyses were conducted to characterize the differences in the FA variables among the clusters. Results: The FA phenotypes were classified into five types: 1) non-asymmetry type (35.8%); 2) maxillary-cant type (14.2%; severe cant of the Max-dent, mild shift of the Man-border); 3) mandibular-shift and yaw type (16.7%; moderate shift and yaw of the Man-border, mild RH-difference); 4) complex type (9.2%; severe cant of the Max-dent, moderate cant, severe shift, and severe yaw of the Man-border, moderate differences in FRA and RH); and 5) maxillary reverse-cant type (24.2%; reverse-cant of the Max-dent). Strategic decompensation by pre-surgical orthodontic treatment and considerations for OGS planning were proposed according to the FA phenotypes. Conclusions: This FA phenotype classification may be an effective tool for differential diagnosis and surgical planning for Class III patients with FA.

Allowable Speed of Tilting Car in the Conventional Line (기존선의 선형조건을 고려한 틸팅차량의 허용속도 평가)

  • 유영화;엄주환;엄기영
    • Journal of the Korean Society for Railway
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    • v.6 no.4
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    • pp.246-251
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    • 2003
  • A quantitative analysis on the amounts of cant and lateral displacement of gravitational center due to the introduction of high-speed tilting car was carried out, based on the current alignment of the conventional line. In addition, the maximum allowable speed in curve and the level of improvement in maximum speed of tilting car were evaluated through the comparison with the maximum speed of locomotive. It was found that the tilting car produces an equivalent amount of cant, which corresponds to 47.5 % of current actual cant. This effect could be explained by the fact that 1.34 m, which is the height of gravitational center of tilting car from the rail level, is much lower than that of locomotive and thus guarantees much higher level of safety in curve. The equivalent amount of cant due to the lateral displacement of gravitational center followed by tilting in curve was 2.4 mm. It was small but not enough to be neglected and must be included in calculating the maximum speed in curve. It could be concluded that the 15 % speed-up of the conventional line is reasonable under the current condition of alignment.

Frankfort horizontal plane is an appropriate three-dimensinal reference in the evaluation of clinical and skeletal cant

  • Oh, Suseok;Ahn, Jaemyung;Nam, Ki-Uk;Paeng, Jun-Young;Hong, Jongrak
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.39 no.2
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    • pp.71-76
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    • 2013
  • Objectives: In three-dimensional computed tomography (3D-CT), the cant is evaluated by measuring the distance between the reference plane (or line) and the tooth. The purpose of this study was to determine the horizontal skeletal reference plane that showed the greatest correlation with clinical evaluation. Materials and Methods: The subjects were 15 patients who closed their eyes during the CT image taking process. The menton points of all patients deviated by more than 3 mm. In the first evaluation, clinical cant was measured. The distance from the inner canthus to the ipsilateral canine tip and the distance from the eyelid to the ipsilateral first molar were obtained. The distance between the left and right sides was also measured. In the second evaluation, skeletal cant was measured. Six reference planes and one line were used for the evaluation of occlusal cant: 1) FH plane R: Or.R - Or.L - Po.R; 2) FH plane L: Or.R - Or.L - Po.L; 3) F. Ovale plane R: Rt.F.Ovale - Lt.F.Ovale - Or.R; 4) F. Ovale plane L: Rt.F.Ovale - Lt.F.Ovale - Or.L; 5) FZS plane R: Rt.FZS - Lt.FZS - Po.R; 6) FZS plane R: Rt.FZS - Lt.FZS - Po.L, and; 7) FZS line: Rt.FZS - Lt.FZS. Results: The clinical and skeletal cants were compared using linear regression analysis. The FH plane R, FH plane L, and FZS line showed the highest correlation (P<0.05). Conclusion: The FH plane R and FH plane L are the most appropriate horizontal reference plane in evaluation of occlusal cant on 3D-CT.