• Title, Summary, Keyword: internal stress

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Effect of Plating Conditions on Internal Stress of Nickel Electrodeposits (電析니켈에 있어서 電着條件이 內部應力에 미치는 影響)

  • Koh, Suck-Soo
    • Journal of the Korean institute of surface engineering
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    • v.13 no.4
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    • pp.211-220
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    • 1980
  • Internal stress of electrodeposited metals affect physical and mechanical characteristics of deposits. Internal stress of nickel deposits was reviewed intensively. Important outcomes are as follows. Substrate have an important effect on internal stress of electrodeposit. Origin of its internal stress could be explained mismatch of crystal lattice and coalescence of crystallites. When surface cleaning is not satisfying, instantaneous stress is low but the electrodeposited layer being thickened increasingly stress become to high and peeling phenomenon occurs. Effect of current density and temperature on internal stress is variable. Internal stress increases rapidly at pH 5 and above because of codepositing colloidal materials caused hydrolysis. Concentrations of nickel ion and $H_3BO_3$ ion affect little on internal stress and solution which contains impurities tend to increase stress. Especially impurities of $H_2O_2$ and iron ion have a great effect on internal stress. Additives are divided in two kind. One is increasing tensile stress another is increasing compressive stress. Concentrations of additives have a great effect on internal stress.

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Study on the Mechanical Properties and Microstructure of Nickel Sulfamate Electroform (니켈쌀파메이트 전주층의 물성과 미세구조)

  • 김인곤
    • Journal of the Korean institute of surface engineering
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    • v.37 no.1
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    • pp.40-48
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    • 2004
  • Hardness and internal stress are very important in nickel electroforming. Nickel sulfamate bath has been widely used in electroforming because of its low internal stress and moderate hardness. Nickel sulfamate bath without chloride was chosen to investigated the effect of plating variable such as temperature, PH, current density and sodium naphthalene trisulfonate as addition agent on the hardness and internal stress. It was found that hardness increased with increasing temperature and decreasing current density and ranged from 150∼310 DPH. The hardness was highest at $55^{\circ}C$ and 10∼40 mA/$\textrm{cm}^2$. The internal stress increased with increasing current density and decreasing temperature. It was minimum at PH 3.0∼3.8. Low internal stress within $\pm$1,500 psi was obtained at both $50^{\circ}C$ and $55^{\circ}C$ in 10-20 mA/$\textrm{cm}^2$. The addition of sodium naphthalene trisulfonate was found to be effective in refine columnar grains thus resulted in decreasing internal stress, increasing hardness and improving brightness.

Analysis of Principal Stresses of O-Ring under Uniform Deformation and Internal Pressure by Stress Freezing Method (응력동결법에 의한 고압기밀용 오링의 주응력 해석)

  • Nam, Jeong-Hwan;Hawong, Jai-Sug;Kim, Young-Tak;Park, Sung-Han;Shin, Dong-Chul
    • Proceedings of the KSME Conference
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    • pp.150-154
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    • 2008
  • In this research, stress components and principal stresses of O-ring under internal pressure and under uniform squeeze rate were obtained from the stress freezing method of photoelastic experiment and photoelastic experimental Hybrid method for 3-dimensional problems. The obtaining processes of those were introduced. It was certified that the processes of those are effective for the 3-dimensional stress analysis of structures. Stress freezing method, the obtaining processes of those and photoelastic experimental hybrid method were effectively applied to the stress analysis of O-ring made from rubber that under uniform deformation and internal pressure. Stress components and principal stress of Oring under uniform squeeze rate and under internal pressure were analyzed.

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Influences of Electrodeposition Variables on Mechanical Properties of Ni-Mn Electrodepositions (Ni-Mn 전착층의 기계적 성질에 미치는 공정조건의 영향)

  • Shin, Ji-Wung;Yang, Seung-Gi;Hwang, Woon-Suk
    • Corrosion Science and Technology
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    • v.13 no.3
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    • pp.102-106
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    • 2014
  • Nickel electrodeposition from sulfamate bath has several benefits such as low internal stress, high current density and good ductility. In nickel deposited layers, sulfur induces high temperature embrittlement, as Ni-S compound has a low melting temperature. To overcome high temperature embrittlement problem, adding manganese is one of the good methods. Manganese makes Mn-S compound having a high melting temperature above $1500^{\circ}C$. In this work, the mechanical properties of Ni-Mn deposited layers were investigated by using various process variables such as concentration of Mn$(NH_2SO_3)_2$, current density, and bath temperature. As the Mn content of electrodeposited layers was increased, internal stress and hardness were increased. By increasing current density, internal stress increased, but hardness decreased. With increasing the bath temperature from 55 to $70^{\circ}C$, internal stress of Ni deposit layers decreased, but hardness didn't change by bath temperature. It was likely that eutectoid manganese led to lattice deformation, and the lattice deformation increased hardness and internal stress in Ni-Mn layers. Increasing current density and decreasing bath temperature would increase a mount of $H_2$ absorption, which was a cause for the rise of internal stress.

Evaluation of Internal Stress and Dislocation Velocity in Creep with 25Cr-20Ni Stainless Steels (25Cr-20Ni계 스테인리스강의 크리프 변형중 내부응력과 운동전위밀도의 평가)

  • Park, In-Duck;Ahn, Seok-Hwan;Nam, Ki-Woo
    • Proceedings of the KSME Conference
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    • pp.296-301
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    • 2004
  • By the purpose to investigate the change of internal stress and mobile dislocation density in creep, the stress relaxation test is carried out in the condition of each strain. Mobile dislocation density increased until it reached minimum creep rate and after that, it decreased and internal stress didn't have the change approximately until it reached minimum creep rate and after that, it decreased. The stress relaxation rate is fast and approached zero after 1.5 seconds after the beginning of the stress relaxation. And the larger the applied stress is, the larger the internal stress is. By the evaluation of mobility of dislocation, the dislocations glide viscously in STS31OJlTB but it is the dislocations glide viscously which N passes by cutting Cr atom rather than typical viscosity movement after calculating mobility of dislocation.

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Evaluation of Internal Stress and Dislocation Velocity in Creep with Austenite Stainless Steels (오스테나이트계 스테인리스강의 크리프 변형중 내부응력과 운동전위밀도의 평가)

  • Kim Hyun Soo;Nam Ki Woo;Park In Duck
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.2
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    • pp.214-219
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    • 2005
  • To investigate the change of internal stress and mobile dislocation density in the creep, stress relaxation test was examined from each strain range. Mobile dislocation density increased until it reached minimum creep rate but after that, it decreased. Internal stress did not change until it reached minimum creep rate but after that, it decreased. The stress relaxation rate is fast and approached zero later 1.5 seconds, which were begun in the stress relaxation. When the applied stress is large, the internal stress is large. It is cleared that dislocations glide viscously which N passes by cutting Cr atom rather than typical viscosity movement by the evaluation of mobility of dislocation in STS310J1TB.

The Correlation between Deviation Indexes of Ryodoraku and Acute Stress in Patients with Functional Dyspepsia

  • Eom, Guk-Hyeon;Lee, Joon-Suk;Kim, Hyun-Kyung;Lee, Seon-Young;Hur, Won-Young;Kim, So-Yeon;Kim, Jin-Sung;Ryu, Bong-Ha;Yoon, Sang-Hyub
    • The Journal of Korean Medicine
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    • v.27 no.4
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    • pp.142-149
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    • 2006
  • Objectives : The aim of this study was to investigate the relationship between stress type and Ryodoraku score (RS) in patients with functional dyspepsia. Methods : 92 (30 male, 62 female) patients with functional dyspepsia were included in this study. Degree of stress was evaluated by GARS and BEPSI scale which can assess acute and chronic stress, respectively. RS of the patients was measured, and mean, sum of gaps and standard deviation (SD) in their RS were taken. First, patients were divided into two groups by sex, and by mean RS $40{\mu}A$ (above and below). GARS and BEPSI scale of each group was compared. Second, correlation between stress scales (GARS and BEPSI) and variation indexes of RS (sum of gaps and SD) was examined. Result : 1. The mean RS is higher in male patients than in female ones. 2. No significant difference was noted in GARS and BEPSI scale associated with above end below the mean $40{\mu}A$ RS. 3. The sum of gaps and SD of RS has significant correlation with GARS scale but not with BEPSI scale. Conclusions : These results suggest that the sum of gaps and SD of RS are associated with acute stress in patients with functional dyspepsia. Thus, it is thought that RS can be useful in assessing acute stress in patients with functional dyspepsia.

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Correlation between Xerostomia, Stress, and Qi Movement Stagnation in Halitosis Patients (구취환자의 구강건조감과 스트레스, 기울의 상관성 분석)

  • Han, Ga-Jin;Kim, Jin-Sung;Seon, Jong-Ki;Son, Ji-Hee;Oh, Seung-Wha;Park, Young-Sun;Jung, Yong-Jae;Jerng, Ui-Min;Park, Jae-Woo;Ryu, Bong-Ha
    • The Journal of Internal Korean Medicine
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    • v.31 no.3
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    • pp.488-499
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    • 2010
  • Objective : This study was designed to investigate the correlation between Qi movement stagnation condition, stress level and xerostomia in halitosis patients. Methods : Ninety-nine halitosis patients visiting the Halitosis Clinic in the hospital of Oriental medicine, Kyung Hee University from January, 2010 to May, 2010 were recruited. The subjects were assessed on their stress levels(based on the Stress Response Inventory), xerostomia symptoms(based on the 8-item Visual Analogue Scale xerostomia questionnaire), and Qi movement stagnation(氣鬱) condition(one of the subcategories in the Qi, blood and water pattern identification(氣血水辨證)). Salivary functions were evaluated using the unstimulated whole salivary flow rate measurements. Results : Compared to the non-Qi movement stagnation group(Qi movement stagnation pattern identification score < 30), the confirmed Qi movement stagnation group(Qi movement stagnation pattern identification score $\geqq$ 30) showed higher levels of xerostomia and stress. In the regression analysis, the Qi movement stagnation condition and stress levels showed a significant correlation. Furthermore, the Qi movement stagnation condition and stress levels each displayed significant correlations with xerostomia. Conclusions : The results of this study suggest that stress and Qi movement stagnation condition contribute to xerostomia symptoms in halitosis patients. Considering the correlation found between the Qi movement stagnation and stress, this study suggests a novel methodology in treating xerostomia, halitosis, and other stress-related disorders through the Qi movement stagnation-related approach.

The Effect of Internal Restraint of Rebar in Shrinkage Stress Analysis of Concrete Slab in Multistory Building (고층건물 콘크리트 슬래브의 건조수축응력 해석에서 철근의 구속효과)

  • Kim Han-Soo;Kim Jae-Keun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.496-499
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    • 2006
  • In this study, a practical method of shrinkage stress analysis on concrete slab in multi-story building is proposed, which considers both internal restraint and external restraint variation resulting from construction sequence. The shrinkage stress due to external restraint is obtained by multiplying relaxation coefficient to elastic shrinkage stress. The additional shrinkage stress due to internal restraint is obtained by residual strain of the elastic analysis. A verification example was analyzed and compared by the proposed method and commercial analysis program that is capable of time-dependent analysis of concrete. The results of 10-story example building show that the internal restraint of reinforcement increases the shrinkage stress considerably at the slabs under loose external restraint.

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Internal Marketing, Job Stress, Organizational Commitment and Turnover Intention in Nursing Organization (간호조직의 내부마케팅, 직무스트레스, 조직몰입, 이직의도 간의 관계)

  • Yoon, Jung-A;Lee, Hae-Jung
    • Journal of Korean Academy of Nursing Administration
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    • v.13 no.3
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    • pp.293-301
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    • 2007
  • Purpose: The purpose of the study was to identify the relationship among internal marketing, job stress, organizational commitment, and turnover intention in nursing organizations in Korea. Methods: One hundred eighty six nurses recruited from 6 general hospitals in South Korea. The data were collected by self-reporting questionnaires and analysed by the SPSS WIN 11.0 program using descriptive statistics, Pearson's correlation coefficients and stepwise multiple regression. Results: Nurses participated in the study reported medium levels of perceived internal marketing, job stress, organizational commitment, and turnover intention. Perceived internal marketing had significant negative correlation with job stress and turnover intention and significant positive correlation with organizational commitment. Employee's management philosophy was a significant predictor of job stress along with characteristics of hospital, and nurse's educational level ($R^2=$ .18). Working environment was a significant predictor of organizational commitment along with monthly income and job stress ($R^2=$ .31). Promotional strategies and communication style in the organization were significant predictors of turnover intention along with organizational commitment and job stress ($R^2=$ .31). Conclusions: This study suggest that future intervention study enhancing internal marketing would lead the positive changes in job stress, organizational commitment, and turnover intention.

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