• Title/Summary/Keyword: re-expansion

Search Result 230, Processing Time 0.023 seconds

Finite Element Analysis of Re-Cold Expansion in Order to Improve the Fatigue Life of Fastener Hole that has been Cold Expanded Before (홀확장법을 적용한 체결홀의 피로수명 개선을 위한 재 홀확장 효과에 대한 유한요소 해석)

  • Jang, Jae-Soon;Yang, Won-Ho;Cho, Myoung-Rea
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.30 no.9 s.252
    • /
    • pp.1110-1115
    • /
    • 2006
  • Cold expansion of fastener holes has been successfully used for many years to impart beneficial compressive residual stresses. Beneficial compressive residual stress of fastener hole that has been cold expanded before is reduced by using of materials for a long time. As a result, fatigue life of material is reduced. So, compressive residual stresses of material have to regenerate by re-cold expansion method. In this paper, it was carried out a finite element analysis about variation of residual stress due to tensile stress and residual stress distribution that was regenerated by re-cold expansion method in the fastener hole. Here, a diversity tensile stress was used. Also, it was performed a finite element analysis according to cold expansion rate of re cold expansion in order to obtain a beneficial compressive residual stress.

Re-expansion Pulmonary Edema -2 Cases Report- (재팽창 폐부종 치험 2례 보고)

  • 강경민
    • Journal of Chest Surgery
    • /
    • v.28 no.1
    • /
    • pp.81-84
    • /
    • 1995
  • Re-expansion pulmonary edema following pneumothorax or hemothorax is clinically uncommon but occasionally life threatening. Clinical details are given of two patients.Ipsilateral pulmonary edema were developed after chest tube insertion due to spontaneous pneumothorax in case I and after evacuation of postoperative hemothorax in case II. The patients were treated with frequent bronchial toilet.The administration of colloid solution and diuretics was effective. The possible mechanisms underlying the edema are discussed.Both increased time of collapse and suction tended to correlate with reexpansion edema.The present two cases provided evidence for longstanding lung collapse and immediate application of suction.

  • PDF

Effect of Market-Wholesaler System on Market Expansion, Re-transaction Intention, and Recommendation Intention

  • ROH, Gye-Ho;YI, Jong-Hyun;CHO, Young-Sam
    • Journal of Distribution Science
    • /
    • v.18 no.5
    • /
    • pp.99-109
    • /
    • 2020
  • Purpose: This study aims to develop and empirically analyze a research model in order to comprehend the relationship among the service quality of market-wholesaler system, re-transaction intention, and recommendation intention of forwarder. Further, we suggest new six factors reflecting the service quality of market-wholesaler system and highlight market expansion of forwarder as a mechanism in the relationship. Research design, data and methodology: The authors developed the new scales measuring the service quality of market-wholesaler system (i.e. trade price, price fluctuation, payment receipt, settlement period, trade information, and customer service) and conducted a cross-sectional survey for 439 forwarders in a wholesale market. And then we performed a series of path analyses to test hypotheses. The hypotheses are as follows. [H1] The service quality of market-wholesaler system will positively affect forwarders' market expansion, [H2] Forwarders' market expansion will positively affect their re-transaction intention, [H3] Forwarders' market expansion will positively affect their recommendation intention, [H4] Forwarders' re-transaction intention will positively affect their recommendation intention. Results: The results showed that all the six factors for the service quality of market-wholesaler system were positively related to market expansion of forwarders. There was a differential effectiveness in the six factors of the service quality. More specifically, the positive effect of customer service factor was the strongest on market expansion of forwarders. And the respective effects of trade price, price fluctuation, settlement period, trade information factors were followed in order. The positive effect of payment receipt factor was the weakest on market expansion of forwarders. Also, market expansion of forwarders was positively related to their re-transaction intention and recommendation intention. Furthermore, market expansion of forwarders was indirectly related to recommendation intention through re-transaction intention as well. Conclusions: The research findings provide important theoretical and practical implications. This study is the first to attempt to test the perception of forwarders for the service quality of market-wholesaler system by developing and using the new scales. Also, there has been a sharp controversy about the effectiveness of market-wholesaler system. The findings support that market-wholesaler system would be activated by empirically verifying the effectiveness of the service quality on the various outcomes.

Efficient Technique of Motion Vector Re-estimation in Transcoding (트랜스 코딩에서의 효율적인 움직임 벡터 재추정 기법 연구)

  • 한두진;박강서;유희준;김봉곤;박상희
    • The Transactions of the Korean Institute of Electrical Engineers D
    • /
    • v.53 no.8
    • /
    • pp.602-605
    • /
    • 2004
  • A novel motion vector re-estimation technique for transcoding into lower spatial resolution is proposed. This technique is based on the fact that the block matching error is proportional to the complexity of the reference block with Taylor series expansion. It is shown that the motion vectors re-estimated by the proposed method are closer to optimal ones and offer better quality than those of previous techniques.

Prediction of the Radiated Emission(RE)s due to the PCB Power-Bus' Resonance Modes and Mitigation of the RE Levels

  • Kahng, Sung-Tek
    • Journal of electromagnetic engineering and science
    • /
    • v.7 no.1
    • /
    • pp.7-11
    • /
    • 2007
  • PCB Power-Bus (comprising power/ground planes) impedance and fields are evaluated by an efficient series expansion method that is suggested in this paper. It is used to investigate the structure's radiated emission(RE) levels and find acceptable ways of loading the power/ground planes such as decoupling capcitor(DeCap)s, balanced feeding and slits, in order to reduce the interferences. Also, the calculations and measurements of a proposed geometry are verified by vector fitting as a analysis model to check the behavior of the slit.

Detonation transmission with an abrupt change in area

  • Hsu, Yao-Chung;Chao, Yei-Chin;Chung, Kung-Ming
    • Advances in aircraft and spacecraft science
    • /
    • v.5 no.5
    • /
    • pp.533-550
    • /
    • 2018
  • Detonation transmission between propane/oxygen (donor) and propane/air (acceptor) with an abrupt area change is experimentally studied. In the donor, there are two types of incident detonation waves: A self-sustained Chapman-Jouguet (CJ) detonation wave and an overdriven detonation wave that is a result of the difference in the initial donor pressure ratios. The piston work is used to characterize the strength of the incident detonation wave. For an incident CJ detonation wave, the re-initiation of a detonation wave in the acceptor depends on the initial pressure in the donor and the expansion ratio. The axisymmetric and non-axisymmetric soot patterns respectively correspond to direct detonation and detonation re-initiation. For an incident overdriven detonation wave, the re-initiation of a detonation wave in the acceptor strongly depends on the degree of overdrive.

Mechanisms of ASR surface cracking in a massive concrete cylinder

  • Kagimoto, Hiroyuki;Yasuda, Yukihiro;Kawamura, Mitsunori
    • Advances in concrete construction
    • /
    • v.3 no.1
    • /
    • pp.39-54
    • /
    • 2015
  • Relative humidity and strains within a massive concrete cylinder (${\varphi}450mm{\times}900mm$) in the drying and the re-saturating process were measured for elucidating the process of ASR surface cracking in concrete. The expansion behavior of mortars in dry atmospheres with various R.H. values and the resaturating process was revealed. Non- or less-expansive layers were formed in near-surface regions in the concrete cylinder in the drying process, but ASR expansions actively progressed in inner portions. After resaturating, R.H. values of near-surface regions rapidly increased with time, but expansions in the regions were found to be very small. However, in the middle portions, of which R.H. values were kept 80% ~ 90% R.H. in the drying process, expansion actively progressed, resulting in further development of surface cracks in the re-saturating process.

Expansion Factors of Cement Mortar Containing Expanding Admixture (팽창재를 포함한 시멘트 모르터의 팽창 요인)

  • 황인동;염희남;정윤중
    • Journal of the Korean Ceramic Society
    • /
    • v.37 no.6
    • /
    • pp.576-582
    • /
    • 2000
  • Two type of expanding cement generally referred to as CSA with Hauyne(3CaO 3Al2O3 CaSO4) and Quick lime(CaO). Hauyne is formed to ettringite when there are presented with CaO and CaSO4, and CaO reacts wtih water to form Ca(OH)2. REcently, the mechanism of compensation and expand mortar or concrete tend to same and it has been used improving on its shrink property. The volume of cement paste varies with its water content shrink with drying and re-wetting. Concrete and mortar works are required shrinking compensation and expansion properties to reduce of potential crack. The use of expansion cement may improve on its shrinking volume changes. CSA dosages for shrinking compensation limited by cement weight, but obtained difference expansion rate with varied W/C or inorganic admixture. This paper studies expansion rate according to expansion cement dosages, water and inorganic admixtures as Silica fume. Therefor, the expansion factor has to considered before the application.

  • PDF

Performance Evaluation of Re-ranking and Query Expansion for Citation Metrics: Based on Citation Index Databases (인용 지표를 이용한 재순위화 및 질의 확장의 성능 평가 - 인용색인 데이터베이스를 기반으로 -)

  • HyeKyung Lee;Yong-Gu lee
    • Journal of the Korean Society for Library and Information Science
    • /
    • v.57 no.3
    • /
    • pp.249-277
    • /
    • 2023
  • The purpose of this study is to explore the potential contribution of citation metrics to improving the search performance of citation index databases. To this end, the study generated ten queries in the field of library and information science and conducted experiments based on the relevance assessment using 3,467 documents retrieved from the Web of Science and 60,734 documents published in 85 SSCI journals in the field of library and information science from 2000 to 2021. The experiments included re-ranking of the top 100 search results using citation metrics and search methods, query expansion experiments using vector space model retrieval systems, and the construction of a citation-based re-ranking system. The results are as follows: 1) Re-ranking using citation metrics differed from Web of Science's performance, acting as independent metrics. 2) Combining query term frequencies and citation counts positively affected performance. 3) Query expansion generally improved performance compared to the vector space model baseline. 4) User-based query expansion outperformed system-based. 5) Combining citation counts with suitability documents affected ranking within top suitability documents.

The effects of blastocyst morphological score and blastocoele re-expansion speed after warming on pregnancy outcomes

  • Yin, Huiqun;Jiang, Hong;He, Ruibing;Wang, Cunli;Zhu, Jie;Li, Yang
    • Clinical and Experimental Reproductive Medicine
    • /
    • v.43 no.1
    • /
    • pp.31-37
    • /
    • 2016
  • Objective: The aim of this study was to investigate associations between the morphology score of blastocysts and blastocoele re-expansion speed after warming with clinical outcomes, which could assist in making correct and cost-effective decisions regarding the appropriate time to vitrify blastocysts and to transfer vitrified-warmed blastocysts. Methods: A total of 327 vitrified-warmed two-blastocyst transfer cycles in women 38 years old and younger were included in this retrospective study. Results: The clinical pregnancy rate (CPR) and implantation rate (IR) of transfers of two good-morphology grade 4 blastocysts vitrified on day 5 (64.1% and 46.8%, respectively) were significantly higher than the CPR and IR associated with the transfers of two good-morphology grade 3 blastocysts vitrified on day 5 (46.7% and 32.2%, respectively). No significant differences were found in the CPR and IR among the transfers of two good-morphology grade 4 blastocysts regardless of the day of cryopreservation. Logistic regression analysis showed that blastocoele reexpansion speed after warming was associated with the CPR. Conclusion: The selection of a good-morphology grade 4 blastocyst to be vitrified could be superior to the choice of a grade 3 blastocyst. Extending the culture of grade 3 blastocysts and freezing grade 4 or higher blastocysts on day 6 could lead to a greater likelihood of pregnancy. Since re-expansion was shown to be a morphological marker of superior blastocyst viability, blastocysts that quickly re-expand after warming should be prioritized for transfer.