• Title/Summary/Keyword: Depth of Edge Influence

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Laser-induced Thermochemical Wet Etching of Titanium for Fabrication of Microstructures (레이저 유도 열화학 습식에칭을 이용한 티타늄 미세구조물 제조)

  • 신용산;손승우;정성호
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.4
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    • pp.32-38
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    • 2004
  • Laser-induced thermochemical wet etching of titanium in phosphoric acid has been investigated to examine the feasibility of this method fur fabrication of microstructures. Cutting, drilling, and milling of titanium foil were carried out while examining the influence of process parameters on etch width, etch depth, and edge straightness. Laser power, scanning speed of workpiece, and etchant concentration were chosen as major process parameters influencing on temperature distribution and reaction rate. Etch width increased almost linearly with laser power showing little dependence on scanning speed while etch depth showed wide variation with both laser power and scanning speed. A well-defined etch profile with good surface quality was obtained at high concentration condition. Fabrication of a hole, micro cantilever beam, and rectangular slot with dimension of tess than 100${\mu}{\textrm}{m}$ has been demonstrated.

Optimum arrangement of stiffener on the buckling behaviour of stiffened composite panels with reinforced elliptical cutouts subjected to non-uniform edge load

  • Kalgutkar, Akshay Prakash;Banerjee, Sauvik;Rajanna, T.
    • Steel and Composite Structures
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    • v.42 no.4
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    • pp.427-446
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    • 2022
  • Cutouts in the beams or plates are often unavoidable due to inspection, maintenance, ventilation, structural aesthetics purpose, and sometimes to lighten the structures. Therefore, there will be a substantial reduction in the strength of the structure due to the introduction of the cutouts. However, these cutouts can be reinforced with the different patterns of ribs (stiffener) to enhance the strength of the structure. The present study highlights the influence of the elliptical cutout reinforced with a different pattern of ribs on the stability performance of such stiffened composite panels subjected to non-uniform edge loads by employing the Finite element (FE) technique. In the present formulation, a 9-noded heterosis element is used to model the skin, and a 3-noded isoparametric beam element is used to simulate the rib that is attached around a cutout in different patterns. The displacement compatibility condition is employed between the plate and stiffener, and arbitrary orientations are taken care by introducing respective transformation matrices. The effect of shear deformation and rotary inertia are incorporated in the formulation. A new mesh configuration is developed to house the attached ribs around an elliptical cutout with different patterns. Initially, a study is performed on the panels with different stiffener schemes for various ply orientations and for different stiffener depth to width ratios (ds/bs) to determine an optimal stiffener configuration. Further, various parametric studies are conducted on an obtained optimal stiffened panel to understand the effect of cutout size, cutout orientation, panel aspect ratio, and boundary conditions. Finally, from the analysis, it can be observed that the arrangement of the stiffener attached to a panel has a major impact on the buckling capacity of the stiffened panel. The stiffener's depth to width ratio also significantly influences the buckling characteristic.

Influence of Clearance in Half-piecing of Sheet Metal (금속판재의 하프피어싱 공정에서의 틈새 영향 연구)

  • Yeon, S.M.;Lee, S.K.;Chung, W.J.;Kim, J.H.
    • Transactions of Materials Processing
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    • v.22 no.8
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    • pp.437-441
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    • 2013
  • Recently, the engraving of letters or a pattern on a product surface has received more attention especially in trying to satisfy the customer requirements. Half-piecing is a protrusion forming process that pierces only 40~50% of the material thickness. In the current study, the half-piercing technique for making clear letters by protruding sheet material was selected and studied. The influence of clearance and penetration depth was investigated by measuring the camber and extruded length of a protrusion after experiments. In addition, a numerical analysis was performed for the same working conditions and compared with experimental results. It is shown that, as the clearance increases, the camber of a protrusion increases rapidly and the extruded length decreases slightly. The deformation pattern around the cutting edge during half-piercing changes from an extrusion mode to a shearing mode as the clearance changes from minus to plus values. It is also confirmed that the experimental results show a good agreement with the numerical analyses.

Influence of access cavity design on calcium hydroxide removal using different cleaning protocols: a confocal laser scanning microscopy study

  • Seda Falakaloglu;Merve Yeniceri Ozata;Betul Gunes;Emmanuel Joao Nogueira Leal Silva;Mustafa Gundogar;Burcu Gucyetmez Topal
    • Restorative Dentistry and Endodontics
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    • v.48 no.3
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    • pp.25.1-25.13
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    • 2023
  • Objectives: The purpose of this study was to evaluate the influence of endodontic access cavities design on the removal of calcium hydroxide medication of the apical third of mandibular incisor root canal walls and dentinal tubules with different cleaning protocols: EDDY sonic activation, Er,Cr:YSGG laser-activated irrigation, or conventional irrigation with IrriFlex. Materials and Methods: Seventy-eight extracted human mandibular incisors were assigned to 6 experimental groups (n = 13) according to the endodontic access cavity and cleaning protocol for calcium hydroxide removal: traditional access cavity (TradAC)/EDDY; ultraconservative access cavity performed in the incisal edge (UltraAC.Inc)/EDDY; TradAC/Er,Cr:YSGG; UltraAC. Inc/Er,Cr:YSGG; TradAC/IrriFlex; or UltraAC.Inc/IrriFlex. Confocal laser scanning microscopy images were used to measure the non-penetration percentage, maximum residual calcium hydroxide penetration depth, and penetration area at 2 and 4 mm from the apex. Data were statistically analyzed using Shapiro-Wilk and WRS2 package for 2-way comparison of non-normally distributed parameters (depth of penetration, area of penetration, and percentage of non-penetration) according to cavity and cleaning protocol with the significance level set at 5%. Results: The effect of cavity and cleaning protocol interactions on penetration depth, penetration area and non-penetration percentage was not found statistically significant at 2 and 4 mm levels (p > 0.05). Conclusions: The present study demonstrated that TradAC or UltraAC.Inc preparations with different cleaning protocols in extracted mandibular incisors did not influence the remaining calcium hydroxide at 2 and 4 mm from the apex.

The Physical Penumbra of the 6MV X-ray (6MV 방사선의 물리학적 Penumbra)

  • Cho Moon-June;Kang Wee-Saing
    • Radiation Oncology Journal
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    • v.9 no.2
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    • pp.333-336
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    • 1991
  • High energy Photon beam has a sharp beam margin due to a less side scatter and the other things. But there still remains a penumbra where the dose changes rapidly in the region near the edge of a radiation beam, although it is short in width. It is suggested that the width of the penumbra depends on the source size, distance from source to diaphragm, source to skin distance, and depth in tissue. However, it is also supposed that the other factors influence the penumbra width. In this paper, we investigate changes of the physical penumbra widths according to various field sizes and depths, by using the three dimensional dosimetry system. As a result, we found that as field size and depth increase, the physical penumbra width also increases.

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Axisymmetric large deflection analysis of fully and partially loaded shallow spherical shells

  • Altekin, Murat;Yukseler, Receb F.
    • Structural Engineering and Mechanics
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    • v.47 no.4
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    • pp.559-573
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    • 2013
  • Geometrically non-linear axisymmetric bending of a shallow spherical shell with a clamped or a simply supported edge under axisymmetric load was investigated numerically. The partial load was introduced by the Heaviside step function, and the solution was obtained by the finite difference and the Newton-Raphson methods. The thickness of the shell was considered to be uniform and the material was assumed to be homogeneous and isotropic. Sensitivity analysis was made for three geometrical parameters. The accuracy of the algorithm was checked by comparing the central deflection, the radial membrane stress at the edge, or the transverse shear force with the solutions of plates and shells in the literature and good agreement was obtained. The main findings of the study can be outlined as follows: (i) If the shell is fully loaded the central deflection of a clamped shell is larger than that of a simply supported shell provided that the shell is not very shallow, (ii) if the shell is partially loaded the central deflection of the shell is sensitive to the parameters of thickness, depth, and partial loading but the influence of the boundary conditions is negligible.

Distance Measure of Vehicle in Lost on The Road (유실된 도로에서 자동차의 떨어진 거리 측정)

  • Shin, Seong-Yoon;Baek, Jeong-Uk;Rhee, Yang-Won
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2010.10a
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    • pp.337-338
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    • 2010
  • Projectile is said that objects thrown on the ground of the atmosphere. This objects exercises the parabolic motion because of the fact under the influence of gravity in the direction perpendicular and it does not include the horizontal force neglecting air resistance. In this paper, the experiment target is where subsidence occurred by that some of the road is lost to a certain depth using projectile motion. It says how far away and falling from the edge of the road when you have gone over the edge of depressed road that a car was driving at a constant speed.

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Analysis of stiffened Al/SiC FGM plates with cutout under uniaxial and localized in-plane edge loadings

  • P. Balaraman;V.M. Sreehari
    • Structural Engineering and Mechanics
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    • v.89 no.6
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    • pp.601-615
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    • 2024
  • Effect of ring and straight stiffeners in the buckling as well as vibration characteristics of metal-ceramic functionally graded plates with cutout subjected to various uniaxial and localized in-plane compressive edge loadings was explored in the present work. In the current work, the distinguishing characteristics of metal and ceramic are merged in a single volume, and power law was used for estimating the material composition throughout thickness. Buckling and free vibration characteristics were studied initially for unstiffened Al/SiC functionally graded plates with cutout. Subsequently, the influence of cutout ratio on buckling load as well as natural frequency for different power law indices was discussed. The functionally graded plate was stiffened by three different stiffener patterns, namely; ring stiffener, straight stiffener, as well as a combination of the ring and the straight stiffener, to enhance the buckling as well as vibration characteristics. The effect of stiffener depth ratio for different stiffener patterns was also presented for functionally graded plates having different cutout sizes under various loading conditions. Such studies on functionally graded material have potential applications in a variety of technological fields including the aerospace and defense sectors.

The Gradient Variation of Thermal Environments on the Park Woodland Edge in Summer - A Study of Hadongsongrim and Hamyangsangrim - (여름철 공원 수림지 가장자리의 온열환경 기울기 변화 - 하동송림과 함양상림을 대상으로 -)

  • Ryu, Nam-Hyong;Lee, Chun-Seok
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.6
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    • pp.73-85
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    • 2015
  • This study investigated the extent and magnitude of the woodland edge effects on users' thermal environments according to distance from woodland border. A series of experiments to measure air temperature, relative humidity, wind velocity, MRT and UTCI were conducted over six days between July 31 and August 5, 2015, which corresponded with extremely hot weather, at the south-facing edge of Hadongsongrim(pure Pinus densiflora stands, tree age: $100{\pm}33yr$, tree height: $12.8{\pm}2.7m$, canopy closure: 75%, N $35^{\circ}03^{\prime}34.7^{{\prime}{\prime}}$, E $127^{\circ}44^{\prime}43.3^{{\prime}{\prime}}$, elevation 7~10m) and east-facing edge of Hamyangsangrim (Quercus serrata-Carpinus tschonoskii community, tree age: 102~125yr/58~123yr, tree height: tree layer $18.6{\pm}2.3m/subtree$ layer $5.9{\pm}3.2m/shrub$ layer $0.5{\pm}0.5m$, herbaceous layer coverage ratio 60%, canopy closure: 96%, N $35^{\circ}31^{\prime}28.1^{{\prime}{\prime}}$, E $127^{\circ}43^{\prime}09.8^{{\prime}{\prime}}$, elevation 170~180m) in rural villages of Hadong and Hamyang, Korea. The minus result value of depth means woodland's outside. The depth of edge influence(DEI) on the maximum air temperature, minimum relative humidity and wind speed at maximum air temperature time during the daytime(10:00~17:00) were detected to be $12.7{\pm}4.9$, $15.8{\pm}9.8$ and $23.8{\pm}26.2m$, respectively, in the mature evergreen conifer woodland of Hadongsongrim. These were detected to be $3.7{\pm}2.2$, $4.9{\pm}4.4$ and $2.6{\pm}7.8m$, respectively, in the deciduous broadleaf woodland of Hamyansangrim. The DEI on the maximum 10 minutes average MRT, UTCI from the three-dimensional environment absorbed by the human-biometeorological reference person during the daytime(10:00~17:00) were detected to be $7.1{\pm}1.7$ and $4.3{\pm}4.6m$, respectively, in the relatively sparse woodland of Hadongsongrim. These were detected to be $5.8{\pm}4.9$ and $3.5{\pm}4.1m$, respectively, in the dense and closed woodland of Hadongsongrim. Edge effects on the thermal environments of air temperature, relative humidity, wind speed, MRT and UTCI in the sparse woodland of Hadongsongrim were less pronounced than those recorded in densed and closed woodland of Hamyansangrim. The gradient variation was less steep for maximum 10 minutes average UTCI with at least $4.3{\pm}4.6m$(Hadongsongrim) and $3.5{\pm}4.1m$(Hamyansangrim) being required to stabilize the UTCI at mature woodlands. Therefore it is suggested that the woodlands buffer widths based on the UTCI values should be 3.5~7.6 m(Hamyansangrim) and 4.3~8.9(Hadongsongrim) m on each side of mature woodlands for users' thermal comfort environments. The woodland edge structure should be multi-layered canopies and closed edge for the buffer effect of woodland edge on woodland users' thermal comfort.

Evaluation of rock cutting efficiency of the actuated undercutting mechanism

  • Jeong, Hoyoung;Wicaksana, Yudhidya;Kim, Sehun;Jeon, Seokwon
    • Geomechanics and Engineering
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    • v.29 no.3
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    • pp.359-368
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    • 2022
  • Undercutting using an actuated disc cutter (ADC) involves more complex cutting mechanism than traditional rock cutting does, requiring the application of various new cutting parameters, such as eccentricity, cutter inclination angle, and axis rotational speed. This study presents cutting-edge laboratory-scale testing equipment that allows performing ADC tests. ADC tests were carried out on a concrete block with a specified strength of 20 MPa, using a variety of cutting settings that included penetration depth (p), eccentricity (e), and linear velocity (v). ADC, unlike pick and disc cutting, has a non-linear cutting path with a dynamic cutting direction, requiring the development of a new method for predicting cutting force and specific energy. The influence of cutting parameters to the cutter forces were discussed. The ratio of eccentricity to the penetration depth (e/p) was proposed to evaluate the optimal cutting condition. Specific energy varies with e/p ratio, and exhibits optimum values in particular cases. In general, actuated undercutting may potentially give a more efficient cutting than conventional pick and disc cutting by demonstrating reasonably lower specific energy in a comparable cutting environment.