• 제목/요약/키워드: residual state

검색결과 636건 처리시간 0.03초

Investigating the Association between Residual State Ownership and Privatized Firm Efficiency

  • NGUYEN, Manh Hoang;VO, Quy Thi
    • The Journal of Asian Finance, Economics and Business
    • /
    • 제7권5호
    • /
    • pp.225-236
    • /
    • 2020
  • This paper examines empirically the net impact of residual state ownership on privatized firm efficiency in the transitional context of Vietnam. Vietnamese privatization has its own characteristics. Instead of mass and full privatization, Vietnam has chosen a partial and gradual path. Thus, it is important to assess the net impact of residual state ownership on privatized firms during the post-privatization period. This study employs stochastic frontier analysis to investigate the association between residual state ownership and the efficiency of privatized firms, using a sample of all privatized firms that are listed on the Vietnamese stock exchanges over the period from 2007 to 2017. Also, two-stage least squares regression is incorporated into the model to deal with potential endogeneity issues. Our study provides evidence that state ownership should not be considered as a pure source of agency problems. Indeed, the net impact of residual state ownership on privatized firm efficiency is non-monotonic, and the relationship between residual state ownership and privatized firm efficiency is under an inverted U-shape. A moderate level (less than 50%) of residual state ownership might be beneficial to privatized firm efficiency whereas too much state ownership is detrimental to the efficiency of privatized firms.

취성재료의 손상후 잔류강도 평가 (Evaluation of Residual Strength in Damaged Brittle Materials)

  • 신형섭;오상엽;서창민
    • 대한기계학회논문집A
    • /
    • 제26권5호
    • /
    • pp.932-938
    • /
    • 2002
  • In structural applications, brittle materials such as soda-lime glasses and ceramics are usually subjected to multiaxial stress state. Brittle materials with cracks or damage by foreign object impacts are apt to fracture abruptly from cracks, because of their properities of very high strength and low fracture toughness. But in most cases, the residual strength of structural members with damage has been tested under uniaxial stress condition such as the 4-point bend test. Depending upon the crack pattern developed, the strength under multiaxial stress state might be different from the one under uniaxial. A comparative study was carried out to investigate the influence of stress state on the residual strength evaluation. In comparable tests, the residual strength under biaxial stress state by the ball-on-ring test was greater than that under the uniaxial one by the 4-point bend test, when a small size indendation crack was introduced. In the case that crack having an angle of 90deg. to the applied stress direction, the ratio of biaxial to uniaxial flexure strength was about 1.12. The residual strength was different from crack angles to loading direction when it was evaluated by the 4-point bend test. The ratio of residual strength of 45deg. crack to 90deg. one was about 1.20. In the case of specimen cracked by a spherical impact, it was shown that an overall decrease in flexure strength with increasing impact velocity, and the critical impact velocity for formation of a radial and/or cone crack was about 30m/s. In those cases that relatively large cracks were developed as compared with the case of indented cracks, the ratio of residual strength under biaxial stress state to one uniaxial became small.

무잔류 응력상태 결정을 통한 표면 잔류응력장 평가에의 레이저 간섭계 적용 (Application of Laser Interferometry for Assessment of Surface Residual Stress by Determination of Stress-free State)

  • 김동원;이낙규;나경환;권동일
    • 반도체디스플레이기술학회지
    • /
    • 제3권2호
    • /
    • pp.35-40
    • /
    • 2004
  • The total relaxed stress in annealing and the thermal strain/stress were obtained from the identification of the residual stress-free state using electronic speckle pattern interferometry (ESPI). The residual stress fields in case of both single and film / substrate systems were modeled using the thermo-elastic theory and the relationship between relaxed stresses and displacements. We mapped the surface residual stress fields on the indented bulk Cu and the 0.5 $\mu\textrm{m}$ Au film by ESPI. In indented Cu, the normal and shear residual stress are distributed over -1.7 GPa to 700 MPa and -800 GPa to 600 MPa respectively around the indented point and in deposited Au film on Si wafer, the tensile residual stress is uniformly distributed on the Au film from 500 MPa to 800 MPa. Also we measured the residual stress by the x-ray diffractometer (XRD) for the verification of above residual stress results by ESPI...

  • PDF

분말사출성형한 W-15 wt%Cu 나노복합분말의 고상소결에 미치는 잔류불순물의 영향 (Effect of Residual Impurities on Solid State Sintering of the Powder Injection Molded W-15 wt%Cu Nanocomposite Powder)

  • 윤의식;이재성;윤태식
    • 한국분말재료학회지
    • /
    • 제9권4호
    • /
    • pp.235-244
    • /
    • 2002
  • The effects of residual impurities on solid state sintering of the powder injection molded (PIMed) W-15wt%Cu nanocomposite powder were investigated. The W-Cu nanocomposite powder was produced by the mech-ano-chemical process consisting of high energy ball-milling and hydrogen reduction of W blue powder-cuO mixture. Solid state sintering of the powder compacts was conducted at $1050^{\circ}C$ for 2~10 h in hydrogen atmosphere. The den-sification of PIM specimen was slightly larger than that of PM(conventional PM specimen), being due to fast coalescence of aggregate in the PIM. The only difference between PIM and PM specimens was the amount of residual impurities. The carbon as a strong reduction agent effectively reduced residual W oxide in the PIM specimen. The $H_2O$ formed by $H_2$ reduction of oxide disintegrated W-Cu aggregates during removal process, on the contrary to this, micropore volume rapidly decreased due to coalescence of the disintegrated W-Cu aggregates during evolution of CO.It can be concluded that the higher densification was due to the earlier occurred Cu phase spreading that was induced by effective removal of residual oxides by carbon.

동영상 교육 프로그램이 자궁적출술 환자의 잔뇨량, 가스배출 및 상태불안에 미치는 효과 (The Effects of the Video Education Program on the Residual urine, Gas Passing and State Anxiety of Hysterectomy Patients)

  • 강경숙;전은미
    • 여성건강간호학회지
    • /
    • 제16권4호
    • /
    • pp.409-418
    • /
    • 2010
  • Purpose: The purpose of this study was to identify the effects of a pre-operation video assisted education program on residual urine, gas passing and state anxiety in women undergoing hysterectomy. Methods: Nonequivalent control group non-synchronized design was used for the study. In the research, video assisted education program was applied to the experimental group while a similar conventional education was done to the control group. The pre-operation state anxiety and post-operation residual urine and gas discharge of both the groups were measured. The data were analyzed using SPSS. Results: The experimental group was significantly higher than control group on gas passing (t=3.04, p=.00). However the residual urine (t=0.34, p=.73) and state anxiety (t=0.81, p=.82) did not make significant differences. Conclusion: This study is very meaningful in that it developed and provided a nursing intervention can positively affect hysterectomy patients. The pre-operation video assisted education program may be an effective nursing intervention that is clinically practical and useful to reduce time of the gas passing of hysterectomy patients after the operation.

Analysis of cavity expansion and contraction in unsaturated residual soils

  • Lukosea, Alpha;Thiyyakkandi, Sudheesh
    • Geomechanics and Engineering
    • /
    • 제28권4호
    • /
    • pp.405-419
    • /
    • 2022
  • Cavity expansion and contraction solutions for cylindrical and spherical cavities in unsaturated residual soils are presented in this paper. Varying soil state in the plastic zone is accounted by a numerical approach, wherein an element-by-element discretization of the plastic zone of both expanding and contracting cavities is carried out. Unlike existing methods utilizing self-similarity technique, the solution procedure enables the prediction of entire soil-state at any stage of expansion and subsequent contraction. It is also applicable for both cavity creation and expansion problems. The approach adopts constant contribution of suction to effective stress (constant Xs drainage condition) for analysis. The analysis procedure is validated by interpreting the previously reported pressuremeter test results in lateritic residual soil. The typical cavity expansion and contraction characteristics of unsaturated Indian lateritic soil were then examined using this solution procedure. The effect of initial soil-state on cavity limit pressure, plastic radius, reverse yield pressure, and reverse plastic radius are also presented.

절삭가공시 잔류응력에 관한 연구 (A Study on Residual stress at Cutting work)

  • 주호윤
    • 한국생산제조학회지
    • /
    • 제6권3호
    • /
    • pp.111-117
    • /
    • 1997
  • The sudden-stop apparatus is made to measure the residual stress of the infinitesimal area at the turning work surface by using the X-ray stress apparatus. This study is trued to make the cutting work the instantaneous stopping state in the normal working state. The behaviour of work material near the tool is estimated. The estimation method is that the distribution of residual stress can be also measured. The object is to clarify and control the mechanism to leave the adequate stress of the finishing surface. It's beginning is due to observe the occurrence state of the residual stress at the cutting work. The result obtained by this study is as follows. The chips are not separated from the work materials at all the cutting experiments of built-up edges or the shearing areas etc. which can be precisely observed by using the sudden-stop apparatus. The strain of movable system which can be seen at the part of working layer means the size of strain. This experiment proves that the working strain should be lessened to make the size of strain control the residual stress happened at the cutting surface.

  • PDF

Seismic fragility assessment of self-centering RC frame structures considering maximum and residual deformations

  • Li, Lu-Xi;Li, Hong-Nan;Li, Chao
    • Structural Engineering and Mechanics
    • /
    • 제68권6호
    • /
    • pp.677-689
    • /
    • 2018
  • Residual deformation is a crucial index that should be paid special attention in the performance-based seismic analyses of reinforced concrete (RC) structures. Owing to their superior re-centering capacity under earthquake excitations, the post-tensioned self-centering (PTSC) RC frames have been proposed and developed for engineering application during the past few decades. This paper presents a comprehensive assessment on the seismic fragility of a PTSC frame by simultaneously considering maximum and residual deformations. Bivariate limit states are defined according to the pushover analyses for maximum deformations and empirical judgments for residual deformations. Incremental Dynamic Analyses (IDA) are conducted to derive the probability of exceeding predefined limit states at specific ground motion intensities. Seismic performance of the PTSC frame is compared with that of a conventional monolithic RC frame. The results show that, taking a synthetical consideration of maximum and residual deformations, the PTSC frame surpasses the monolithic frame in resisting most damage states, but is more vulnerable to ground motions with large intensities.

Application of Gamma Irradiation for the Reduction of Residual Nitrite and Nitrosamine in Meat Products

  • Ahn, Hyun-Joo;Kim, Jae-Hun;Lee, Ju-Woon;Jo, Cheorun;Byun, Myung-Woo
    • 한국축산식품학회지
    • /
    • 제24권4호
    • /
    • pp.367-372
    • /
    • 2004
  • Nitrite, a curing agent of meat products, is precursors of carcinogenic N-nitrosamines during processing of meat products or under human stomach conditions as well as having its own toxicity. Some researches have been conducted to evaluate the effects of ionizing radiation on the reduction of residual nitrite and N-nitrosamines in an aqueous model system and cured meat products with different packaging methods during storage. These results showed that the gamma irradiation was effective in reducing the residual nitrite and N-nitrosamines in an aqueous model system as well as meat products. Especially, irradiation combined with vacuum or modified atmosphere packaging was more effective in nitrite and N-nitrosamines reduction than aerobic packaging during storage. The objective of this review is to introduce the irradiation technology for the application of reducing the residual nitrite and N-nitrosamine contents in meat products.

열연 공정 정상상태 판 프로파일 예측 - PartⅡ: 수식 모델 개발 (Prediction of Steady-state Strip Profile during Hot Rolling - PartⅡ: Development of a Mathematical Model)

  • 이재상;황상무
    • 소성∙가공
    • /
    • 제25권1호
    • /
    • pp.61-66
    • /
    • 2016
  • In the current study, we present a new model for the prediction of the strip profile and the residual stresses. This new approach is an analytical model that predicts the residual stresses from the effect of post-deformation. Since the residual stress cannot exceed the yield strength of the material, post-yielding may possibly occur in the post-deformation zone prior to the strip reaching the steady-state zone. The prediction accuracy of the proposed model is examined through comparison with the predictions from 3-D finite element (FE) simulations.