• Title/Summary/Keyword: Asymmetric tooth

Search Result 11, Processing Time 0.035 seconds

Optimal Design of a Two-phase BLDC Motor Considering Efficiency and Torque Ripple

  • Kim, Jae-Beom;You, Yong-Min;Kang, Sun-Il;Kwon, Byung-Il
    • Journal of Electrical Engineering and Technology
    • /
    • v.8 no.5
    • /
    • pp.1131-1137
    • /
    • 2013
  • This paper introduces novel a two-phase permanent magnet BLDC (PMBLDC) motor with both an asymmetric tooth and an auxiliary tooth in order to improve the dead point, efficiency and torque ripple. To calculate the merits of introducing each of the asymmetric tooth and the auxiliary tooth, characteristic analysis is performed respectively using finite element method (FEM). To maximize performance, we propose a novel model which combines the asymmetric tooth and the auxiliary tooth. To maximize the efficiency of the novel model, an optimal design is processed using the Kriging method and a genetic algorithm. Finally, an experiment is used to confirm the initial and optimal design results.

A THREE-DIMENSIONAL FEM COMPARISON STUDY ABOUT THE FORCE, DISPLACEMENT AND INITIAL STRESS DISTRIBUTION ON THE MAXILLARY FIRST MOLARS BY THE APPLICATION OF VAR10US ASYMMETRIC HEAD-GEAR (비대칭 헤드기어의 적용시 상악제 1 대구치에 나타나는힘과 변위 및 초기 응력분포에 관한 3차원 유한요소법적 연구)

  • Kim, Jong-Soo;Cha, Dyung-Suk;Ju, Jin-Won;Lee, Jin-Woo
    • The korean journal of orthodontics
    • /
    • v.31 no.1 s.84
    • /
    • pp.25-38
    • /
    • 2001
  • The purpose of this study was to compare the force, the displacement and the stress distribution on the maxillary first molars altered by the application of various asymmetric head-gear. For this study, the finite element models of unilateral Cl II maxillary dental arch was made. Also, the finite element models of asymmetric face-bow was made. Three types of asymmetric face-bow were made : each of the right side 15mm, 25mm and 35mm shorter than the left side. We compared the forces, the displacement and the distribution of stress that were generated by application of various asymmetric head-gear, The results were as follows. 1. The total forces that both maxillary first molars received were similar in all groups. But the forces that mesially positioned tooth received were increased as the length of the outer-bow shortened, and the forces that normally positioned tooth received were decreased as the length of the outer-bow shortened. 2. In lateral force comparison, the buccal forces that normally positioned tooth received were increased as the length of the outer-bow shortened, and the buccal fortes that mesially positioned tooth received were decreased as the length of the outer-bow shortened. Though the net lateral force moved to the buccal side of normally positioned tooth as the length of the outer-bow shortened, both maxillary first molars received the buccal force. That showed 'Avchiai Expansion Effect' 3. The distal forces, the extrusion forces and the magnitudes of the crown distal tipping that mesially positioned tooth received were increased as the length of the outer-bow shortened, and the forces that normally positioned tooth received were decreased as the length of the outer-bow was shortened. 4. The magnitude of the distal-in rotation that normally positioned tooth received were increased as the length of the outer-bow was shortened. But, mesially positioned tooth show two different results. For the outer-bow 15mm shortened, mesially positioned tooth showed the distal-in rotation, hut for the outer-bow 25mm and 35mn shortened, mesially positioned tooth showed the distal-out rotation. Thus, the turning point exists between 15mm and 25mm. 5. This study of the initial stress distribution of the periodontal ligament at slightly inferior of the furcation area revealed that the compressive stress in the distobuccal root of the normally positioned tooth moved from the palatal side to the distal side and the buccal side successively as the length of the outer-bow shortened. 6. This study of the initial stress distribution of the periodontal ligament at slightly inferior of the furcation area revealed that the magnitudes of stress were altered but the total stress distributions were not altered in the mesiobuccal root and the palatal root of normally positioned tooth, and also three roots of mesially positioned tooth as the length of the outer-bow shortened.

  • PDF

A FEM comparison study about the force, displacement and initial stress distribution on the maxillary first molars by the application of Asymmetric Head-Gears with the different traction forces (Asymmetric Head-Gear의 견인력의 차이에 따른 상악 제 1 대구치에 나타나는 힘과 변위 및 초기 응력분포에 관한 유한요소법적 비교 연구)

  • Cha, Kyung-Suk
    • The korean journal of orthodontics
    • /
    • v.31 no.3 s.86
    • /
    • pp.311-323
    • /
    • 2001
  • One of the various mechanics used to treat unilateral Class II malocclusion is head gear with asymmetric face bow. We made the finite element models of unilateral Class II maxillary dental arch and power arm asymmetric face bow. We designed this experiment to observe stress distribution of periodontal ligament, reaction force, and displacement and to understand force system, so to predict the therapeutic effect. On the basis of computerized tomograph of maxillary dental arch of 25 years old male with normal occlusion without extraction and orthodontic treatment history, we made finite element models of maxillary dental arch and periodontal ligament. Then we modified that model to unilateral maxillary Class II malocclusion model of which maxillary left molar displaced mesially. Also, We made finite element model of asymmetric face bow of which right outer bow shorter than left by 25mm(RMO, Penta-FormTM/Medium size, 0.045 inch iner bow, 0.072 inch outer bow). After that, retraction force of 250g, 300b, 350g were applied to maxillary first molar. We concluded as follow. 1. The Net force that both maxillary first molars were received increased as the retraction force increased. Mesially positioned tooth received more force than normally positioned tooth. But, both tooth were received distal force, so distal movement occured. 2. Both tooth received buccal lateral force. In analysis of force element, as the retraction force were increased, force of X-axis at mesially positioned tooth decreased, and force of X-axis at normally positioned tooth increased. so lateral force component moved to the side received less force from more force. 3. There were rotation, tipping with distal movement in maxillary first molar. As retraction force were increased, rotation and tipping also increased. More tipping and rotation occured at the side received more force, that is, mesially positioned tooth. Though it Is small change, displacement of same pattern occur in normally positioned tooth

  • PDF

Excremental Study on Wave Drag in Supersonic Wavy Walls (초음속 파동 벽면에서의 조파저항에 관한 실험적 연구)

  • Kwon, Min-Chan;Semenov, Vasily V.
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2010.11a
    • /
    • pp.758-759
    • /
    • 2010
  • In this study, it was experimentally confirmed that the phenomenon of resonance effect of wave drag in two wavy walls. The channel had saw-tooth type of relief surfaces when supersonic gas flows into this channel. Experiment was carried out on the differential apparatus by conducting the comparative test of two nozzles (round sonic nozzle and two-dimensional nozzle with wavy walls). The two-dimensional nozzle was joined alternately with flat walls which had saw-tooth type of symmetrical and asymmetric reliefs. Two-dimensional nozzle was designed for the M=3 and profiled parabolic contour.

  • PDF

Radiographic evaluation of dentigerous cyst with cone beam CT (콘빔형전산화단층장치를 이용한 함치성낭의 방사선학적 연구)

  • Park, Yong-Chan;Lee, Wan;Lee, Byung-Do
    • Imaging Science in Dentistry
    • /
    • v.40 no.3
    • /
    • pp.115-121
    • /
    • 2010
  • Purpose : The purpose of this study was to accurately analyze the radiographic characteristics of dentigerous cyst (DC) with multiplanar images of cone beam computed tomography (CBCT). Materials and Methods : Thirty eight radiographically and histopathologically proven cases of DCs were analyzed with panoramic radiograph and CBCT, retrospectively. The radiographic CT pattern, symmetry of radiolucency around the unerupted tooth crown, ratio of long length to short length, degree of cortical bone alternation, effects on adjacent tooth, and cyst size were analyzed. Relative frequencies of these radiographic features were evaluated. In order to compare the CBCT features of DC with those of odontogenic keratocyst (OKC), 9 cases of OKCs were analyzed with the same method radiographically. Results : DCs consisted of thirty unilocular cases (79.0%), seven lobulated cases (18.4%) and one multilocular case (2.6%). Eight were asymmetric (21.0%) and thirty were symmetric (79.0%). Maxillary DC showed rounder shape than mandibular DC (L/S ratio; maxilla 1.32, mandible 1.67). Alternations of lingual cortical bone (14 cases, 48.2%) were more frequent than those of buccal side (7 cases, 24.1%). CBCT images of DC showed definite root resorption and bucco-lingual tooth displacement. These findings were hardly observed on panoramic radiographs of DCs. Comparison of CBCT features of DC with those of OKC showed several different features. Conclusions : CBCT images of DC showed various characteristic radiographic features. Therefore, CBCT can be helpful for the diagnosis of DC radiographically.

Treatment of unilateral buccal crossbite with mandibular symphyseal distraction osteogenesis

  • Ozkalayci, Nurhat;Ozer, Mete;Sumer, Mahmut
    • The korean journal of orthodontics
    • /
    • v.41 no.1
    • /
    • pp.59-69
    • /
    • 2011
  • The aim of this report is to present the treatment of a 14-year-old boy with scissors-bite. Mandibular symphyseal distraction osteogenesis (MSDO) with tooth-supported distractor was performed to expand the mandible, and intermaxillary cross elastics were used. The mandible was expanded approximately 9 mm. Asymmetric widening was done by using cross elastics and MSDO simultaneously. The buccal crossbite was corrected successfully. After a 2-year observation period, widening of the mandible using this procedure was judged to be stable.

A Study on the Design of the Carrier Phase Difference for the Planetary Gear Noise Reduction (유성기어 소음저감을 위한 캐리어 위상차 설계에 관한 연구)

  • Park, Ki-Ho;Kim, Tai-Hoon;Jung, Sang-Jin;Wee, Hyuk;Lee, Gook-Sun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2011.04a
    • /
    • pp.230-231
    • /
    • 2011
  • There is a merit a planetary gear set disperses a delivery load, and to decrease loss of friction and noise. But, in addition to meshing this internal and external gear simultaneously and phase difference by the tooth contact point and the time difference occurs asymmetric and symmetric sideband noise and vibration caused by the modulation in the vehicle. Existing planetary gear set research have progressed to reduce the cause of the sideband as run-out, pitch error and imbalance. In this paper presents a method for the design of the carrier phase difference by developing various theorys and experiments for gear noise.

  • PDF

A Development of the Planetary Gear Noise for 6-speed RWD Automatic Transmission (후륜 6 속 자동변속기 유성기어 소음 개발)

  • Park, Ki Ho;Kim, Tai Hoon;Jung, Sang jin;Kim, Yunkyoo;Lee, Jeong Seon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2012.10a
    • /
    • pp.544-545
    • /
    • 2012
  • In recent years, vehicle manufacturers have steadily developed fuel saving technologies such as multi-speed automatic transmission. With such a background, the Hyundai-powertech have developed the new 6-speed rear wheel drive(RWD)automatic transmission for FR vehicles. Despite having six-speed, it has the same number of planetary gears as a previously used five-speed automatic transmission and fewer brakes and one-way clutches than the 5 A/T, meaning that it is light, compact, and inexpensive. But, in addition to meshing this internal and external gear simultaneously and phase difference by the tooth contact point and the time difference occurs asymmetric and symmetric sideband noise and vibration caused by the modulation in the vehicle. In this paper presents a method for the design of the carrier phase difference by developing various theories and experiments for gear noise.

  • PDF

Perception of discrepancy in the upper midline position in conjunction with the gingival display according to various occupations in Iran

  • Hooman Zarif Najafi;Taraneh Estedlal;Maryam Saki;Maryam Azadi
    • The korean journal of orthodontics
    • /
    • v.53 no.3
    • /
    • pp.163-174
    • /
    • 2023
  • Objective: This study evaluated the influence of various gingival displays on the esthetic perception in the presence of upper dental midline discrepancy. Methods: A smiling image of a male subject was altered digitally to produce five image series: normal smile (series A), decreased tooth show (series B), increased gingival show (series C), maxillary cant (series D), and asymmetric upper lip elevation (series E). In each image series, the midline was deviated to the right and left incrementally. A total of 210 raters (four professional groups and laypersons, n = 42 in each group) determined the midline deviation threshold and the attractiveness of midline position in each series. Results: The right and left thresholds were statistically similar for the symmetrical series (A, B, and C), while for series D, the right threshold was significantly lower. In most rater groups, the mean threshold order was: B > A > E > C > D. In all the series, the raters selected the coincident midline as the most attractive series except for series D, for which 1-2-mm deviations to the left were selected as the most attractive by almost all the groups. Conclusions: It is crucial to establish the coincident midline position in a symmetrical smile, especially when a gummy smile exists. In the asymmetrical gingival show, a coincident midline might not be the most esthetic midline position.

Correlation between menton deviation and dental compensation in facial asymmetry using cone-beam CT (Cone-beam CT를 이용한 안면비대칭자에서 이부편위에 따른 치성보상의 양상분석)

  • Park, Soo-Byung;Park, Jeong-Heuy;Jung, Yun-Hoa;Jo, Bong-Hye;Kim, Yong-Il
    • The korean journal of orthodontics
    • /
    • v.39 no.5
    • /
    • pp.300-309
    • /
    • 2009
  • Objective: The purpose of this study was to evaluate the correlation between menton deviation and dental compensation in facial asymmetry. Methods: Tooth axis and distance of first molar and canine to the reference plane were investigated by cone-beam computerized tomography. The subjects consisted of 50 patients with asymmetric mandibles (male 21, female 29, mean age 24.3 years). Control groups were also assessed (male 11, female 9, mean age 25.6 years). Nine measurements (5 linear measurements and 4 angular measurements) were measured in order to evaluate the correlation between menton deviation and the linear and angular difference of first molar and canine in the deviated and none-deviated sides using the defined MPR images. The differences between deviated and non-deviated side, according to menton deviation, were statistically analyzed using stepwise multiple regression analysis. Results: From the result, Menton deviation was negatively correlated with mandibular first molar's angular measurement (${\Delta\angle}LM6$-Mn plane (dev.-ndev.)) and positively with maxillary fist molar's angular measurement (${\Delta\angle}UM6$-FH plane (dev.-ndev.)) (p < 0.01). Two angular measurements (${\Delta\angle}LM6$-Mn plane (dev.-ndev.), ${\Delta\angle}UM6$-FH plane (dev.-ndev.)) explained the variability in menton deviation with a significant $r^2$ value of 0.589. Conclusions: This study suggests that the tooth axis of upper and lower first molars leans towards the deviated side of Menton when there is mandibular asymmetry with Menton deviation.