• Title/Summary/Keyword: Bend test

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The Study of Human Rights Sensitivity and the Types of Perception in regards to Human Rights for College Students (대학생의 인권감수성 수준과 인권인식 유형에 관한 연구)

  • Shim, Tae Een;Lee, Song Yi
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.10
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    • pp.352-360
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    • 2018
  • The purpose of this study was to examine the level of human rights sensitivity and the types of perception in regards to the human rights of college students to enhance their human rights sensitivity. The study methodology included a t-test and variance analysis for the level of human rights sensitivity, and a Q-factor analysis for the perception types of human rights. As a result of examining whether there is a difference in human right sensitivity, it was found that female students were higher than male students, and juniors and seniors were higher than freshmen and sophomores. The human rights sensitivity of the students in the social and science department were the highest, and those who had volunteer experiences were more susceptible to human rights than those who did not. Students who registered for organ donation were higher than those who did not, and those who received human rights education showed higher human rights susceptibility than those who did not. Four perception types of human rights were analyzed 'universal social moralists', those who have an idealistic mindset and make decisions based on moral standards, 'practical realists', those who have no intention of breaking out of the social norm and who do not want to take any risks for human rights, 'social system advocates', those who have a clear understanding of the basic human rights concept, but don't think that they should break the rules of society for the sake of individual rights, and 'social contracts advocates', those who are willing to bend the rules of society for human rights, but not to the extent of ruining relationships. These study results are expected to contribute to the possibility of the social viewpoint that human rights sensitivity can be developed in the context of social experience as well as perception.

Flexural Strength of HSB Steel Girders Due to Inelastic Lateral-Torsional Buckling - Sections with Slender Web (HSB 강거더의 비탄성 횡비틂좌굴에 의한 휨강도 - 세장 복부판 단면)

  • Cho, Eun-Young;Shin, Dong-Ku
    • Journal of Korean Society of Steel Construction
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    • v.24 no.2
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    • pp.217-231
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    • 2012
  • The flexural behavior of HSB I-girder with a non-slender web attributed to inelastic lateral-torsional buckling under uniform bending was investigated using nonlinear finite element analysis of ABAQUS. The girder was assumed to have a compact or noncompact web in order to prevent premature bend-buckling of the web. The unbraced length of the girder was selected so that inelastic lateral-torsional buckling governs the ultimate flexural strength. The compression flange was also assumed to be either compact or noncompact to prevent local buckling of the elastic flange. Both homogeneous sections fabricated from HSB600 or HSB800 steel and hybrid sections with HSB800 flanges and SM570-TMC web were considered. In the FE analysis, the flanges and web of I-girder were modeled as thin shell elements. Initial imperfections and residual stresses were imposed on the FE model. An elasto-plastic strain hardening material was assumed for steel. After establishing the validity of the present FE analysis by comparing FE results with test results in existing literature, the effects of initial imperfection and residual stress on the inelastic lateral-torsional buckling behavior were analyzed. Finite element analysis results for 96 sections demonstrated that the current inelastic strength equations for the compression flange in AASHTO LTFD can be applied to predict the inelastic lateral torsional buckling strength of homogeneous and hybrid HSB I-girders with a non-slender web.

Resistance Curves of Concrete CLWL-DCB Specimens (콘크리트 CLWL-DCB 시험편의 저항곡선)

  • 연정흠
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.357-364
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    • 2002
  • The resistance curves (R-curves) for 381 m crack extension of CLWL-DCB specimens had been determined. The average velocities of the crack extension measured with strain gages were 0.70 and 55 ㎜/sec. The measured rotation angle of the notch faces showed the existence of the singularity at least before 171 and 93 mm crack extensions for the 0.70 and 55 ㎜/sec crack velocities, respectively. The maximum slopes of the R-curves occurred between 25 and 89 ㎜ crack extensions for 0.70 ㎜/sec crack velocity and between 51 and 127 ㎜ crack extensions for 55 ㎜/sec crack velocity During the maximum slopes of the R-curves, the micro-crack localization can be expected, and faster crack velocity may form longer micro-cracking and micro-crack localizing zones. The fracture resistance of 0.70 ㎜/sec crack velocity reached a roughly constant maximum value of 143 N/m at 152 ㎜ crack extension, while that of 55 ㎜/sec crack velocity increased continuously to 245 N/m at 254 ㎜ crack extension and then decreased to the value of 0.70 ㎜/sec crack velocity. The R-curve of 55 ㎜/sec crack velocity was similar to that of the small size three-point bend test, and it showed that small size specimen or fast crack velocity could cause more brittle behavior.

A Convergence Study on Changes in the Muscle Activity around the Neck of the Operator according to the Patient's Head Angle at the Direct Visual Inspection of the Maxillary Right-side Molar Palatal Surface (상악 우측 대구치 구개면의 직접 시진 시 환자 머리 각도에 따른 술자의 목 주변 근육활성도 변화의 융합적 연구)

  • Lee, Sook-Jeong
    • Journal of the Korea Convergence Society
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    • v.9 no.11
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    • pp.209-216
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    • 2018
  • This study aimed to investigate the association of the muscle activity around the neck of the operator(dental hygienists') according to the change in the patient's neck angle during a direct visual inspection on the maxillary right-side molar palatal surface. The operators were $4^{th}$ year dental hygiene students, who are future dentalhy gienists, having accurate understanding on and awareness of the location of the operation site, hand fixation, and how to use the tools. Data on the change in the muscle activity around the neck were collected by using surface electromyography and neck goniometer. SPSS statistics 20 was used for statistical analyses including Shapiro-wilk test and one-way ANOVA. As a result, the activities of the operator upper trapezius, cervical erector spinae, and levator scapulae muscles significantly decreased when the patient's head was angled compared to when it was not. For the angle of the operator head, the head bend significantly decreased when the patient's head was angled than when it was not. Based on the study results, it is expected that angling the patient's head when treating his or her teeth will decrease the excessive muscle activity around the neck of the operator, and will reduce muscle fatigue. Therefore, angling the head of the patient while treating his or her teeth is recommended. This suggests that muscle pain caused by repetitive actions in the wrong posture can be reduced.

The Effect of Inline Skate Program on Physical Fitness(PAPS-D) Improvement of Student with Developmental Disability (인라인스케이트 프로그램이 발달장애 학생들의 건강체력(PAPS-D) 향상에 미치는 효과)

  • Chol, Jae-Yong;Kim, Ji-Sun
    • Journal of the Korean Applied Science and Technology
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    • v.36 no.2
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    • pp.541-550
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    • 2019
  • This study is aimed to find out the effect of PAPS-D on physical fitness of developmental disabled students who participated of Inline skate program. The subject of this study was 10 middle and high school students diagnosed as developmental disability. The subject attended a total of 32 classes twice a week for 16 weeks and the class was 1 hour each time. Improvement of physical fitness was assessed based on PAPS-D program developed by the Department of Education science in 2016 except for obesity measurement; cardio pulmonary function (walking in 6 minutes), flexibility (seated forward bend, clasped hand behind the back), muscle function (sit-up) and agility (standing long jump). To find out the interaction between control group and experimental group, two-way repeated measure ANOVA was used. As a result, there was a statistically significant relation in cardio pulmonary function and agility but not in flexibility and muscle function. 3 variables (cardio pulmonary function, flexibility and muscle function) among 4 variables showed positive effect of Inline skate program on physical fitness while one variable which was agility showed decreased result in post-test. Based on the results of three variables that were found to have improved in the pre post-examination, the result of this study indicates positive effect of Inline skating program on physical fitness of developmentally disabled students.

Comparison of flexural strength according to thickness between CAD/CAM denture base resins and conventional denture base resins (CAD/CAM 의치상 레진과 열중합 의치상 레진의 두께에 따른 굴곡 강도 비교)

  • Lee, Dong-Hyung;Lee, Joon-Seok
    • Journal of Dental Rehabilitation and Applied Science
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    • v.36 no.3
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    • pp.183-195
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    • 2020
  • Purpose: The purpose of this study is to compare the flexural strength of CAD/CAM denture base resins with conventional denture base resins based on their thicknesses. Materials and Methods: For the conventional denture base resins, Lucitone 199® (C-LC) was used. DIOnavi - Denture (P-DO) and DENTCA Denture Base II (P-DC) were taken for the 3D printing denture base resins. For the prepolymerized PMMA resins, Vipi Block Gum (M-VP) and M-IVoBase® CAD (M-IV) were used. The final dimensions of the specimens were 65.0 mm x 12.7 mm x 1.6 mm / 2.0 mm / 2.5 mm. The 3-point bend test was implemented to measure the flexural strength and flexural modulus. Microscopic evaluation of surface of fractured specimen was conducted by using a scanning electron microscope (SEM). After testing the normality of the data, one-way ANOVA was adopted to evaluate the differences among sample groups with a significance level of P = 0.05. The Tukey HSD test was performed for post hoc analysis. Results: Under the same thicknesses, there are significant differences in flexural strength between CAD/CAM denture base resins and conventional denture base resins except for P-DO and C-LC. M-VP showed higher flexural strength than conventional denture base resins, P-DC and M-IV displayed lower flexural strength than conventional denture base resins. Flexural modulus was highest in M-VP, followed by C-LC, P-DO, P-DC, M-IV, significant differences were found between all materials. In the comparison of flexural strength according to thickness, flexural strength of 2.5 mm was significantly higher than that of 1.6 mm in C-LC. Flexural strength of 2.5 mm and 2.0 mm was significantly higher than that of 1.6 mm in P-DC and M-VP. In M-IV, as the thickness increases, significant increase in flexural strength appeared. SEM analysis illustrates different fracture surfaces of the specimens. Conclusion: The flexural strength of different CAD/CAM denture base resins used in this study varied according to the composition and properties of each material. The flexural strength of CAD/CAM denture base resins was higher than the standard suggested by ISO 20795-1:2013 at a thickness of 1.6 mm or more though the thickness decreased. However, for clinical use of dentures with lower thickness, further researches should be done regarding other properties at lower thickness of denture base resins.

Effects of heat treatment on the load-deflection properties of nickel-titanium wire (니켈-티타늄 와이어의 열처리에 따른 부하-변위 특성 변화)

  • Chang, Soo-Ho;Kim, Kwang-Won;Lim, Sung-Hoon
    • The korean journal of orthodontics
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    • v.36 no.5
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    • pp.349-359
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    • 2006
  • Objective: Nickel-titanium alloy wire possesses excellent spring-back properties, shape memory and super-elasticity. In order to adapt this wire to clinical use, it is necessary to bend as well as to control its super-elastic force. The purpose of this study is to evaluate the effects of heat treatment on the load-deflection properties and transitional temperature range (TTR) of nickel-titanium wires. Methods: Nickel-titanium wires of different diameters ($0.016"\;{\times}\;0.022"$, $0.018"\;{\times}\;0.025"$ and $0.0215"\;{\times}\;0.028"$) were used. The samples were divided into 4 groups as follows: group 4, posterior segment of archwire (24 mm) without heat treatment; group 2, posterior segment of archwire (24 mm) with heat treatment only; group 3, anterior segment with bending and heat treatment; group 4, anterior segment with bending and 1 sec over heat treatment. Three point bending test was used to evaluate the change in load-deflection curve and obtained DSC (different scanning calorimetry) to check changes in $A_f$ temperature. Results: In the three point bending test, nickel-titanium wires with heat treatment only had higher load-deflection curve and loading and unloading plateau than nickel-titanium wires without heat treatment. Nickel-titanium wires with heat treatment had lower Af temperature than nickel-titanium wires without heat treatment. Nickel-titanium wires with heat treatment and bending had higher load-deflection curve than nickel- titanium wires with heat treatment and nickel-titanium wires without heat treatment. Nickel-titanium with heat treatment of over 1 sec and bending had the highest load-deflection curve. Nickel-titanium wires with heat treatment and bending had lower Af temperature, Nickel-titanium wires with heat treatment of over Af sec and bending had the lowest Af temperature. Conclusion: From the results of this study, it can be stated that heat treatment for bending of Nickel-titanium wires does not deprive the superelastic property but can cause increased force magnitude due to a higher load-deflection curve.