• Title/Summary/Keyword: influence surface

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A Study on the Influence of the Physical Properties of Mortar on Surface Shape of Crushed Sand (부순모래의 표면형상이 모르터의 물성에 미치는 영향)

  • 이승한;김종인;윤용호;한형섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.51-56
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    • 1997
  • This study is aimed for investigating the influence of mortar on improved of surface shape of crushed sand, and analyzing the physical properties of fresh state and hardened state. By the test results, it was found that the flow value and bleeding ratio was increased, but the change of flow value according to time was decreased with the improved surface shape of crushed sand. Also, comparing improved of surface shape of crushed sand with not improved of surface shape of crushed sand on strength, compressive strength is about the same and flexural strength decrease in case of improved of surface shape of crushed sand.

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Influence of Wavy Surface on the Turbulence in the Outer Layer (파형 벽면이 외층의 난류량에 미치는 영향에 대한 고찰)

  • Na, Yang
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.8
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    • pp.1053-1059
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    • 2001
  • Results from direct numerical simulation and LDV measurements are analyzed to investigate the influence of structured surface on turbulence in the outer layer. To provide a well-defined surface roughness, sinusoidal wavy surface was used. Even though flows over smooth and wavy surface show very different process for maintaining turbulence in the vicinity of the wall, there are some evidences that the turbulence in the outer layer has a universal characteristics and it may be possible to give a speculative interpretation that similarity of turbulent structures arises because Reynolds stress producing motion is similar regardless of different turbulence generation mechanisms embedded in both cases.

Influence of Working Variables in Simplified Gear Shaving Process (단순 기어형상의 셰이빙가공에 있어서 작업 변수의 영향)

  • Lee, K.S.;Jung, J.Y.;Kim, J.H.
    • Transactions of Materials Processing
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    • v.19 no.5
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    • pp.290-295
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    • 2010
  • Shaving technology is one of the significant metal forming technologies which can make the smooth and fine sheared surface of products after shearing process. The sheared surface on the side wall of the cutting edge is very important because it functions as a basic surface for measuring the dimensions of product. Effective sheared surface after shaving can be influenced by several working variables such as shaving allowance, shaving clearance, type of material and profile of cutting edge. The influence of these variables on shaving characteristics was investigated in this study. A cut-off die to make the simplified gear-shaped products was manufactured. Three kinds of sheet metals (AL5052, SPCC and SAPH440) of 3mm thickness were firstly sheared and then shaved for four shaving allowances and three sharing clearances. It was shown through experiments that the optimum working condition to give the maximum effective sheared surface in shaving was found ; Shaving allowance is 0.2mm and Shaving clearance is 0.01mm.

Dispersion of Aqueous $Al_2O_3$Suspensions with Electrolytes; Influence of the Counter Ion

  • Cecile Pagnoux;Richard Laucournet;Thierry Chartier;Baumard, Jean-Francois
    • The Korean Journal of Ceramics
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    • v.6 no.3
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    • pp.280-285
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    • 2000
  • The electrolyte, $(HO)_2C_6H_2(SO_3Na)_2H_2O $(Tiron), disperses efficiently alumina powder in aqueous media and stable suspensions with 60 vol% solid loading can be prepared. The strong adsorption of this additive is mainly due to the ability of the molecule to form chelate rings with the particle surface but electrostatic interactions between the surface charge and the anionic dispersant strongly influence the amount of Tiron adsorbed. By using a cationic exchange route to substitute the counter ion which neutralizes the sulfonate groups, new molecules of dispersant have been prepared, either with mineral cations as $Li^+,\; Na+^,\; NH_4^\;+$, or with organic cations as counter ion but organic counter ions lead to less to less viscous suspensions than $Na^+$ in particular when the number of carbon atoms of the aliphatic chain increases from 1 to 3.

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Surface-enhanced Raman Spectroscopy of Ethephone Adsorbed on Silver Surface

  • Lee, Chul-Jae;Kim, Hee-Jin;Karim, Mohammad Rezaul;Lee, Mu-Sang
    • Bulletin of the Korean Chemical Society
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    • v.27 no.4
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    • pp.545-548
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    • 2006
  • We investigated the Surface-enhanced Raman Spectroscopy (SERS) spectrum of ethephone (2-chloroethylphosphonic acid). We observed significant signals in the ordinary Raman spectrum for solid-state ethephone as well as when it was adsorbed on a colloidal silver surface, strong vibrational signals were obtained at a very low concentration. The SERS spectra were obtained by silver colloids that were prepared by the $\gamma$-irradiation method. The influence of pH and the influence of anion $(Cl^-,\;Br^-,\;I^-)$ on the adsorption orientation were investigated. Two different adsorption mechanisms were deduced, depending on the experimental conditions. The chlorine atom or the chlorine and two oxygen atoms were adsorbed on the colloidal silver surface. Among halide ions, $Br^-$ and $I^-$ were more strongly adsorbed on the colloidal silver surfaces. As a result, the adsorption of ethephone was less effective due to their steric hinderance.

Influence of Die Design Variables on the Sheared Surface in Shearing Process of Sandwich Sheet Metal (샌드위치 강판의 전단가공에 있어서 전단면에 미치는 금형 설계 변수의 영향)

  • Kim J. Y.;Chung W. J.;Kim J. H.
    • Transactions of Materials Processing
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    • v.14 no.1 s.73
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    • pp.37-42
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    • 2005
  • In order to invstigate the influence of die design variables on the quality of the sheared surface in cutting of sandwich sheet metals, the cut-off operation is carried out, which is the typical shearing process in sheet metal forming technology. For experiments we made the cut-off die which can be easily adjusted for die design variables such as blankholding force, pad force and clearance. The sandwich sheet metals considered are clad304(STS304-Al1050-STS304) and anti-vibration sheet metal. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results it is shown that the shearing mechanisms are different according the material of which sandwitch sheet metal is composed. The influence of die design variable is explored and we found optimal conditions for both sandwich sheet metals. It is expected that this investigation can be utilized to get the better sheared surface.

Influence of Operating Condition on Grinding Temperature in High Effect Grinding (고능률 가공에서 연삭 온도에 미치는 연삭 조건의 영향)

  • 김남경;강대민;송지복
    • Journal of the Korean Society of Safety
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    • v.5 no.1
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    • pp.31-39
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    • 1990
  • In this paper, the influence of the table speed, metal removal rate and grinding fluid on long wheel workpiece contact zone at high effect grinding was investigated by theoretical analyses and measuring the temperature, and discussed by the temperature distribution in grinding surface layer. Main results obtained are as follows, 1) Rega.dless of the table speed, the temperature gap of the workpiece(heat influx) is about 6-8 times as high in dry condition as in wet condition. 2) Good grinding condition can be obtained owing to the effect of grinding fluid without any burning defect under the condition of the metal removal rate(1.0mm$^3$/mm.s) in case of wet grinding. 3) When the depth from the surface layer is about 1.25-1.5mm under the condition of the slow table speed, surface temperature goes up higher as the table speed slows down, because long contact time is laked at the surface layer. 4) In case of the same metal removal rate, the lower the table speed becomes, the higher the surface temperature is, because grinding depth has a far more influence on wheel workpiece contact zone than the table speed.

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Laser decontamination for radioactive contaminated metal surface: A review

  • Qian Wang;Feisen Wang;Chuang Cai;Hui Chen;Fei Ji;Chen Yong;Dasong Liao
    • Nuclear Engineering and Technology
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    • v.55 no.1
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    • pp.12-24
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    • 2023
  • With the improvement of laser technology, the strategic needs of efficient and precise decontamination of various components in nuclear application units can be fulfilled by laser decontamination. The surface contaminants of nuclear facilities mainly exist both as loose contaminated layer and fixed oxide layer. The types of radionuclides and contamination layer thickness are closely related to the operation status of nuclear facilities, which have an important influence on the laser decontamination process. This study reviewed the mechanism of laser surface treatment and the influence of laser process parameters on the decontamination thickness, decontamination factor, decontamination efficiency and the distribution of aerosol particle. Although multiple studies have been performed on the mechanism of laser processing and laser decontamination process, there are few studies on the microscopic process mechanism of laser decontamination and the influence of laser decontamination on surface properties. In particular, the interaction between laser and radioactive contaminants needs more research in the future.