• Title/Summary/Keyword: P2P1 element

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STRESS ANALYSIS ON THE DIFFERENT CLASPS OF THE REMOVABLE PARTIAL DENTURE BY THREE-DIMENSIONAL FINITE ELEMENT METHOD (삼차원 유한 요소법에 의한 가철성 국소의치 클래스프의 응력 분석)

  • Park Hong-Ryul;Kim Seong-Kyun;Koak Jai-Young;Heo Seong-Joo;Chang Ik-Tae
    • The Journal of Korean Academy of Prosthodontics
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    • v.43 no.2
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    • pp.218-231
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    • 2005
  • Statement of problem. In the partially edentulous patients, removable partial dentures have been working as a important treatment modality. Clasps, a kind of direct retainers, received some amount of stresses during the insertion and removal of partial denture on the abutment tooth. Purpose. The study is to investigate stresses of the different clasps. Material and methods. In order to investigate the degree of stresses, maxillary partial edentulism (Kennedy Class II modification I) was assumed and removable partial dentures were designed on it with three kinds of metallic materials; cobalt-chromium alloy, type IV gold alloy and commercially pure (c.p.) titanium. Aker's clasp was applied on the left second molar. RPA (mesial rest-proximal plate-Aker's) clasp was on the left first premolar and wrought wire clasp was on the right first premolar. Three dimensional, non-linear, dynamic finite element analysis method was run to solve this process. Results. 1. Cobalt-chromium alloy had the highest von Mises stress value and c.p. titanium had the lowest one irrespective of the types of clasps. 2. In the Aker's clasps, stress on the retentive tips was shown shortly after the appearance of stresses of the middle and minor connector areas. These time lag was much shorter in the RPA clasps than in the Aker's clasp. 3. In general. retentive tips of wrought wire clasps had much less amount of stress than other clasps. Conclusion. The amount of stress was the highest in the RPA clasp and the lowest in the wrought wire clasp, in general.

A Study on the Temporomandibular Joint Disorder and School Life Stress of High School Student by Department (계열별 남자고등학생의 학교생활스트레스와 측두하악장애에 관한 연구)

  • Lee, Jung-Hwa;Choi, Jung-Mi
    • Journal of dental hygiene science
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    • v.7 no.3
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    • pp.179-185
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    • 2007
  • The purpose of this study targeted on high school student in the department of liberal arts, industry in Daegu metropolitan city, is to get basic data necessary for the development of dental educational program, to discern prevention and treatment of temporomandibular joint disorder by observing the situation temporomandibular joint disorder and contribution element, of relationship of school life stress The results are as follows.: 1. The percentage of occurring temporomandibular joint disorder in the high school resulted in a joint noise at 61.8% and joint dislocation 6.9%, sharp pain 47.5% at time of chewing. 29.8% at the time of the non-chewing, lockjaw 11.3%, a headache appeared at 40.4%.2. In the contribution factor of occurring temporomandibular joint disorder, the cause of joint noise was the clench one's teeth, lip and cheek clench, For the pain at the time of chewing clench one's teeth, one side chewing, over-chewing, lip clench, sideways sleeping showed the difference. (P < 0.01) For the pain at the time of non-chewing, clench one's teeth, bruxism, one side chewing, lip and cheek clench were similar, and for the lockjaw, clench one's teeth, bruxism, sideways sleeping showed the difference. The plum evil thing period at time of the fault writing that statistically showed the difference. For the headache, the contribution factors were the all bad habits mentioned above excluding one side sleeping.(P < 0.01, P < 0.05). 3. The rate of experiencing temporomandibular joint disorder by oral and maxillofacia was 13.4% in industrial department, and 19.6% in liberal arts. And for the factor of wound was that exercise 26.8%, others 24.4%, fall-down 19.5%. And for the industrial, exercise 44.4%, fall-down 22.2%, others 14.9%. The treatment experience appeared at 5.0% in industrial department, 2.9% in liberal arts. And for the medical institutions, liberal arts were dental clinic 50%, orthopedics 50%, and the industrial department orthopedics 40%, oriental medicine clinic 30%, dental clinic 30%. 4. In case of temporomandibular joint disorder, there were no difference by grades or educational background. And at the time of chewing or non-chewing showed similar difference.(P < 0.01). 5. Compared to stress in the high school, it generally showed higher in liberal arts than in industrial department due to school record. Its scope was $3.75{\pm}1.14$ in liberal arts, $3.01{\pm}1.23$ in industrial department. 6. The school record, school life, stress problems by teachers, chewing/non-chewing pain of temporomandibular joint disorder, joint noise had a similar correlation.(P < 0.01, < 0.05).

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Evaluating Measurements: A Comparative Study of Digital and Plaster Models for Orthodontic Applications in Mixed Dentition

  • Seo Young Shin;Yong Kwon Chae;Ko Eun Lee;Mi Sun Kim;Ok Hyung Nam;Hyo-seol Lee;Sung Chul Choi
    • Journal of the korean academy of Pediatric Dentistry
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    • v.51 no.1
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    • pp.55-65
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    • 2024
  • This study aimed to assess the accuracy of tooth widths, intermolar widths, and arch lengths acquired through two intraoral scanners, including iTero Element Plus Series (Align Technology, Santa Clara, CA, USA) and Trios 4 (3Shape, Copenhagen, Denmark), specifically on mixed dentition. A total of 30 subjects were divided into 2 groups, each undergoing both alginate impressions and intraoral scanning using either the iTero or Trios scanner. The plaster models were measured with a caliper, while the digital models were measured virtually. In the iTero group, all tooth width measurements exhibited differences compared to the plaster values, except for maxillary left lateral incisors (p = 0.179), mandibular right (p = 0.285), and left (p = 0.073) central incisors. The Trios group did not display significant differences in any of the tooth width measurements. Intermolar width comparisons for both groups indicated differences, except for mandibular primary canine to primary canine values (p = 0.426) in the iTero group. Regarding arch length, the mandibular anterior, maxillary right, and left arch lengths in the iTero group demonstrated larger caliper values than those of iTero. Conversely, in the Trios group, all parameters showed smaller caliper values, especially in upper anterior, maxillary right, mandibular right, and mandibular left arch lengths with significance (p = 0.027, 0.007, 0.003, and 0.047, respectively). Despite the differences between the two groups, digital models might be clinically suitable alternatives for plaster models. Pediatric dentists should carefully assess these differences, as a comprehensive evaluation would result in precise orthodontic treatment planning and favorable outcomes for young patients with mixed dentition.

Finite element modeling of bond-slip performance of section steel reinforced concrete

  • Liu, Biao;Bai, Guo-Liang
    • Computers and Concrete
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    • v.24 no.3
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    • pp.237-247
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    • 2019
  • The key issue for the finite element analysis (FEA) of section steel reinforced concrete (SRC) structure is how to consider the bond-slip performance. However, the bond-slip performance is hardly considered in the FEA of SRC structures because it is difficult to achieve in the finite element (FE) model. To this end, the software developed by Python can automatically add spring elements for the FE model in ABAQUS to considering bond-slip performance. The FE models of the push-out test were conducted by the software and calculated by ABAQUS. Comparing the calculated results with the experimental ones showed that: (1) the FE model of SRC structure with the bond-slip performance can be efficiently and accurately conducted by the software. For the specimen with a length of 1140 mm, 3565 spring elements were added to the FE model in just 6.46s. In addition, different bond-slip performance can also be set on the outer side, the inner side of the flange and the web. (2) The results of the FE analysis were verified against the corresponding experimental results in terms of the law of the occurrence and development of concrete cracks, the stress distribution on steel, concrete and steel bar, and the P-S curve of the loading and free end.

Geochemical and Nd-Sr Isotope Studies for Foliated Granitoids and Mylonitized Gneisses from the Myeongho Area in Northeast Yecheon Shear Zone (예천전단대 북동부 명호지역 엽리상 화강암류와 압쇄 편마암류에 대한 지구화학 및 Nd-Sr 동위원소 연구)

  • Kim, Sung-Won;Lee, Chang-Yun;Ryu, In-Chang
    • Economic and Environmental Geology
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    • v.41 no.3
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    • pp.299-314
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    • 2008
  • The NE-trending Honam shear zone is a broad, dextral strike-slip fault zone between the southern margin of the Okcheon Belt and the Precambrian Yeongnam Massif in South Korea and is parallel to the trend of Sinian deformation that is conspicuous in Far East Asia. In this paper, we report geochemical and isotopic(Sr and Nd) data of mylonitic quartz-muscovite Precambrian gneisses and surrounding foliated hornblende-biotite granitoids near the Myeongho area in the Yecheon Shear Zone, a representative segment of the Honam Shear Zone. Foliated hornblende-biotite granitoids commonly plot in the granodiorite field($SiO_2=61.9-67.1\;wt%$ and $Na_2O+K_2O=5.21-6.99\;wt%$) on $SiO_2$ vs. $Na_2O+K_2O$ discrimination diagram, whereas quartz-muscovite Precambrian orthogneisses plot in the granite field. The foliated hornblende-biotite granitoids are mostly calcic and calc-alkalic and are dominantly magnesian in a modified alkali-lime index(MALI) and Fe# [$=FeO_{total}(FeO_{total}+MgO)$] versus $SiO_2$ diagrams, which correspond with geochemical characteristics of Cordilleran Mesozoic batholiths. The foliated hornblende-biotite granitoids have molar ratios of $Al_2O_3/(CaO+Na_2O+K_2O)$ ranging from 0.89 to 1.10 and are metaluminous to weakly peraluminous, indicating I type. In contrast, Paleoproterozoic orthogneisses have peraluminous compositions, with molar ratios of $Al_2O_3/(CaO+Na_2O+K_2O)$ ranging from 1.11 to 1.22. On trace element spider diagrams normalized to the primitive mantle, the large ion lithophile element(LILE) enrichments(Rb, Ba, Th and U) and negative Ta-Nb-P-Ti anomalies of foliated hornblende-biotite granitoids and mylonitized quartz-muscovite gneisses in the Yecheon Shear Zone are features common to subduction-related granitoids and are also found in granitoids from a crustal source derived from the arc crust of active continental margin. ${\varepsilon}_{Nd}(T)$ and initial Sr-ratio ratios of foliated hornblende-biotite granitoids with suggest the involvement of upper crust-derived melts in granitoid petrogenesis. Foliated hornblende-biotite granitoids in the study area, together with the Yeongju Batholith, show not changing contents of specific elements(Ti, P, Zr, V and Y) from shear zone to the area near the shear zone. These results suggest that no volume changes and geochemical alterations in fluid-rich foliated hornblende-biotite granitoids may occur during deformation, which mass transfer by fluid flow into the shear zone is equal to the mass transfer out of the shear zone.

Study on Design Parameters of Substrate for PoP to Reduce Warpage Using Finite Element Method (PoP용 Substrate의 Warpage 감소를 위해 유한요소법을 이용한 설계 파라메타 연구)

  • Cho, Seunghyun;Lee, Sangsoo
    • Journal of the Microelectronics and Packaging Society
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    • v.27 no.3
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    • pp.61-67
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    • 2020
  • In this paper, we calculated the warpage of bare substrates and chip attached substrates by using FEM (Finite Element Method), and compared and analyzed the effect of the chips' attachment on warpage. Also, the effects of layer thickness of substrates for reducing warpage were analyzed and the conditions of layer thickness were analyzed by signal-to-noise ratio of Taguchi method. According to the analysis results, the direction of warpage pattern in substrates can change when chips are attached. Also, the warpage decreases as the difference in the CTE (coefficient of thermal expansion) between the top and bottom of the package decreases and the stiffness of the package increases after chips are loaded. In addition, according to the impact analysis of design parameters on substrates where chips are not attached, in order to reduce warpage, the inner layers of the circuit layer Cu1 and Cu4 has be controlled first, and then concentrated on the thickness of the solder resist on the bottom side and the thickness of the prepreg layer between Cu1 and Cu2.

MEMS-BASED MICRO FLUXGATE SENSOR USING SOLENOID EXCITATION AND PICK-UP COILS (MEMS 공정 제작방법에 의한 솔레노이드형 여자 코일과 검출코일을 사용한 마이크로 플럭스게이트 센서)

  • 나경원;박해석;심동식;최원열;황준식;최상인
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.172-176
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    • 2002
  • This paper describes a MEMS-based micro-fluxgate magnetic sensing element using Ni$\_$0.8/Fe$\_$0.2/ film formed by electroplating. The micro-fluxgate magnetic sensor composed of a thin film magnetic core and micro-structured solenoids for the pick-up and the excitation coils, is developed by using MEMS technologies in order to take advantage of low-cost, small size and lower power consumption in the fabrication. A copper with 20um width and 3um thickness is electroplated on Cr(300${\AA}$)/Au(1500${\AA}$) films for the pick-up(42turn) and the excitation(24turn) coils. In order to improve the sensitivity of the sensing element, we designed the magnetic core into a rectangular-ring shape to reduce the magnetic flux leakage. An electroplated permalloy film with the thickness of 3 $\mu\textrm{m}$ is obtained under 2000Gauss to induce magnetic anisotropy. The magnetic core has the high DC effective permeability of ∼1,100 and coercive field of -0.1Oe. The fabricated sensing element using rectangular-ring shaped magnetic film has the sensitivity of about 150V/T at the excitation frequency of 2MHz and the excitation voltage of 4.4Vp-p. The power consumption is estimated to be 50mW.

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Contact analysis in functionally graded layer loaded with circular two punches

  • Muhammed T. Polat;Alper Polat
    • Computers and Concrete
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    • v.33 no.1
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    • pp.13-25
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    • 2024
  • In this study, contact analysis in a functionally graded (FG) layer loaded with two circular punches is solved using the finite element method (FEM). The problem is consisted of a functionally graded layer that resting on an elastic semi-infinite plane and is loaded with two rigid punches of circular geometry. External loads P and Q are transferred to the layer via two rigid punches. The finite element model of the functionally graded layer is created using the ANSYS package program and a 2-dimensional analysis of the problem is analyzed. The contact lengths, obtained as a result of the analysis are compared with the analytical solution in the literature. In the study, the effects of parameters such as distances between punches, loads, inhomogenity parameter on contact zones, initial separation loads and distances, normal stresses, stresses across depth and contact stresses are investigated. As a result, in this study, it can be said that the magnitude of the stresses occurring in the FG layer is less than the homogeneous layer, therefore the life of FG materials will be longer than the homogeneous layer. When the distance between the punches is 2.25, the initial separation distance is 6.98, and when the distance between the punches is 4, the initial separation distance decreases to 6.10. In addition, when the load increased in the second punch, the initial separation load decreased from 55 to 18. The obtained results are presented in the form of graphs and tables.

Dynamic Stability of Cylindrical Shells Subjected to Follower Forces (종동력을 받는 원통셸의 동적 안정성에 관한 연구)

  • 김현순;김지환
    • Journal of KSNVE
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    • v.8 no.2
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    • pp.336-345
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    • 1998
  • The dynamic instability of cylindrical shell with clamped-free boundary condition subjected to constant follower force or $P_0 + P_1cos {\Omega}_t$ type pulsating follower force is analyzed. The motion of shell is modeled using the shell theory considering rotary inertia and shear deformation, and analyzed with finite element method. In case of constant follower force, the changes of eigenvalues dependent on the magnitude of applied load are investigated and the critical loads are obtained. In case pulsating follower force, instability regions of exicitation frequency are obtained by modal transform with right and left modal matrix and by multiple scales method. The effects of thickness ratio and aspect ratio on the instability of shell are studied.

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Content and Distribution of Transition Metals and Rare Earth Elements in Magnetically and Mechanically Separated Brown Coal Ash

  • Malikov, Sh.R.;Pikul, V.P.;Mukhamedshina, N.M.;Sandalov, V.N.;Kudiratov, S.;Ibragimova, E.M.
    • Journal of Magnetics
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    • v.18 no.3
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    • pp.365-369
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    • 2013
  • Coal ash is known to contain a noticeable amount of valuable elements, including transition metals and lanthanides. Therefore it is quite actual problem to extract them for metallurgy and other applications. This paper presents the results of high gradient magnetic and mechanical separation, microscopy, element analyses and optical spectroscopy of brown coal ash taken from the combustion camera and chimney-stalk of Angren thermal power station. The separated magnetic fraction was 3.4 wt.%, where the content of Fe in ferrospheres increased to 58 wt.%. The highest contents of Fe and rare earth elements were found in the fine fractions of $50-100{\mu}m$. Optical absorption spectroscopy of water solutions of the magnetic fractions revealed $Fe^{2+}$ and $Fe^{3+}$ ions in the ratio of ~1:1. The separated coal ash could be used for cleaning of technological liquid waste by means of the high gradient magnetic field.