• Title/Summary/Keyword: stabilization method

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Stabilization of Meles Delta soils using cement and lime mixtures

  • Onal, Okan;Sariavci, Cagrihan
    • Geomechanics and Engineering
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    • v.19 no.6
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    • pp.543-554
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    • 2019
  • İzmir Bay reserves high amount of residual alluvial deposits generated by Meles River at its stream mouth. These carried sediments with high water content and low bearing capacity are unsuitable in terms of engineering purposes. In-situ soil stabilization with deep soil mixing method is considered to improve properties of soil in this location. This method is widely used especially over Scandinavia, Japan and North America. Basically, the method covers mixing appropriate binder into the soil to improve soil profile according to the engineering needs. For this purpose, soil samples were initially provided from the site, classification tests were performed and optimum ratios of lime and cement binders were determined. Following, specimens representing the in-situ soil conditions were prepared and cured to be able to determine their engineering properties. Unconfined compression tests and vane shear tests were applied to evaluate the stabilization performance of binders on samples with different curing periods. Scanning electron microscope was used to observe time-dependent bonding progress of binders in order to validate the results. Utilization of 4% lime and 4% cement mixture for the long-term performance and 8% lime and 8% cement mixture for short term performance were suggested for the stabilization of Meles Delta soils. Development of CSH and CAH in a gel form as well as CSH crystals were clearly observed on SEM images of treated specimens.

Review of the Flame Stabilization Techniques using Cavity (Cavity를 이용한 화염안정화 기술 리뷰)

  • Lee, Tae Ho
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.4
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    • pp.104-111
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    • 2016
  • The flame stabilization is one of the topics which have to be solved for the airbreathing propulsion systems, using the entering air which is supersonic velocity as an oxygen sources. Making a recirculation zone with an eddy flow, installed the reducing velocity devices such as the bluff body, is the typical method of the flame stabilization. Recently using a cavity flame stabilization at the wall is an emerging technique as an effective method which extends the stabilization zone, and the related research papers have been published on the flow separation and reattachment, pressures and oscillations including length/depth ratios in the cavities. Even though, still there are lots of topics to study more in the cavity flame stabilization field as the preceding techniques, as well as the research and the development of the airbreathing propulsion system itself.

The Effect of Dynamic Neuromuscular Stabilization (DNS) on the Respiratory Function of Subjects with Forward Head Posture (FHP)

  • Bae, Won-Sik
    • Journal of the Korean Society of Physical Medicine
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    • v.16 no.3
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    • pp.55-64
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    • 2021
  • PURPOSE: The purpose of this study was to apply dynamic neuromuscular stabilization (DNS) to subjects with forward head posture (FHP) and to compare its effects on respiratory function as against the conventional neck stabilization exercise and neck stretching and extensor strengthening exercises. METHODS: The whole-body posture measurement system was used to measure the degree of FHP, and a spirometer and a respiratory gas analyzer were used to measure the respiratory function. After the intervention was completed, the changes over time were analyzed in the DNS group, the neck stabilization exercise group, and the neck stretching and extensor strengthening exercise group. The inter-group difference in the changes was also analyzed. A repeated ANOVA was performed to compare the respiratory function according to the period between the three groups, and the least significant difference (LSD) method was used for the post hoc test. RESULTS: After the 6-week exercise period, respiratory functions, such as forced vital capacity (FVC), forced expiratory volume for 1 second (FEV1), forced expiratory volume for 1 sec/forced vital capacity (FEV1/FVC), maximum oxygen intake (VO2max), and the volume of expired gas (VE), significantly improved according to the period (p < .05), but no inter-group differences were found. CONCLUSION: DNS is an effective training method, and can be applied along with neck stabilization exercise and neck stretching and extensor strengthening exercises, which are widely used in clinical practice, to people with FHP who cannot directly perform neck exercises to improve their respiratory function.

What is the Optimal Application Method of Rhythmic Stabilization or Stabilizing Reversals to Improve Balance? (균형 향상을 위한 율동적 안정 또는 안정적 반전의 효과적인 적용방법은?)

  • Shin, Seung-Sub
    • PNF and Movement
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    • v.15 no.2
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    • pp.125-132
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    • 2017
  • Purpose: This study reviewed articles to identify the optimal rhythmic stabilization or stabilizing reversals application method for improving balance. Methods: The Cochrane, EBSCO, eArticle, Embase, DBpia, KISS, Medline, ProQuest, PubMed, SAGE, ScienceDirect, Scopus, Springer, and Wiley databases were used to search articles from 1990 to January 2017. The search terms included: "rhythmic stabilization" and "stabilizing reversals." Only experimental human studies (randomized controlled trials) that compared the effects of varying the optimal application of rhythmic stabilization or stabilizing reversals to improve balance were included in the review. Non-English language (except Korean) and unpublished studies were excluded. Results: During the research, 1,098 articles were initially identified. Of these articles, nine were randomized controlled trials. Of these nine articles, five were in English, and four were in Korean. In addition, three of the trials did not measure the patients' balance, two did not report the intensity and location of the resistance, and three performed the rhythmic stabilization incorrectly. Only one article met the inclusion and exclusion criteria. The remaining study evaluated the participants' performance of the alternating trunk flexor and extensor isometric contraction of the scapulae using the optimal resistance for 10 seconds in a sitting position. The participants completed three sets of eight repetitions with rest intervals of 30 seconds between the repetitions and 60 seconds between the sets. Conclusion: Due to the lack of the scientific research on the topic, this review may not provide the evidence needed to support the optimal application of rhythmic stabilization or stabilizing reversals to improve balance. Future research should consider the methodological quality to identify the proper rhythmic standardization and stabilizing reversals application method.

Feasibility study on a stabilization method based on full spectrum reallocation for spectra having non-identical momentum features

  • Kilyoung Ko ;Wonku Kim ;Hyunwoong Choi;Gyuseong Cho
    • Nuclear Engineering and Technology
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    • v.55 no.7
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    • pp.2432-2437
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    • 2023
  • Methodology for suppressing or recovering the distorted spectra, which may occur due to mutual non-uniformity and nonlinear response when a multi-detector is simultaneously operated for gamma spectroscopy, is presented with respect to its applicability to stabilization of spectra having the non-identical feature using modified full spectrum reallocation method. The modified full-spectrum reallocation method is extended to provide multiple coefficients that describe the gain drift for multi-division of the spectrum and they were incorporated into an optimization process utilizing a random sampling algorithm. Significant performance improvements were observed with the use of multiple coefficients for solving partial peak dislocation. In this study, our achievements to confirm the stabilization of spectrum having differences in moments and modify the full spectrum reallocation method provide the feasibility of the method and ways to minimize the implication of the non-linear responses normally associated with inherent characteristics of the detector system. We believe that this study will not only simplify the calibration process by using an identical response curve but will also contribute to simplifying data pre-processing for various studies as all spectra can be stabilized with identical channel widths and numbers.

폐금속광산 주변 오염물질의 안정화 처리

  • Gwon Ji-Cheol;Jeong Myeong-Chae;Jeong Mun-Yeong
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2006.04a
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    • pp.41-44
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    • 2006
  • The objective of this study was to evaluate the stabilization of As and heavy metals in tailings from the Samkwang Au-Ag mine with $Ca(OH)_2$. In order to evaluate the stabilization ability of As and heavy metals in the tailings, column test was implemented with various conditions as 1) particle size of $Ca(OH)_2$, 2) mixing method and 3) flow rate of eluents during 60 days. The results showed that addition with 5% of $Ca(OH)_2$ in 1kg of the tailings had the most effective ability of stabilization up to 95%. In addition, stabilization ability of As and heavy metals in tailings was enhanced using a fine powder of $Ca(OH)_2$. Therefore, stabilization technology can be used as a remediation of As and heavy metals in mine wastes including tailings and a nearby soils from abandoned metal mines.

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Effect of Electron Beam Currents on Stabilization of Polyacrlonitrile Precursor Fiber (PAN 전구체 섬유의 안정화시 전자선 전류의 영향)

  • Shin, Hye Kyoung;Jeun, Joon Pyo;Kim, Hyun bin;Kang, Phil Hyun
    • Journal of Radiation Industry
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    • v.5 no.1
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    • pp.41-46
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    • 2011
  • Polyacrylonitrile (PAN) fibers are the most widely used precursor of the materials for carbon fibers. The conventional process of carbon fibers from PAN precursor fiber includes two step; stabilization at low temperature and carbonization at high temperature. Compared to thermal stabilization, the stabilization process by electron beam (E-beam) irradiation is a advanced and brief method. However, a stabilization by E-beam irradiation was required a high dose (over 5,000 kGy) and spend over 1.5 hr (1.14 MeV, 1 mA). In the present work the main goal is exploring a quick stabilization process by cotrolling E-beam currents. The effect of various E-beam currents on stabilization of PAN precursor fiber was studied by gel fraction test, thermo gravimertic analysis (TGA), differential scanning calorimetry (DSC), tensile strength, and scanning electron microscopy (SEM) images.

Improving Performance of Digital Image Stabilization using Adoptive motion estimation Area selection (적응적 움직임 추정영역 선택을 사용한 영상안정화 성능개선)

  • Kim, Dong-Gyun;Lee, Jin-Hee;Yoo, Yoon-Jong;Paik, Joon-Ki
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.45 no.5
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    • pp.18-24
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    • 2008
  • In this paper we propose a novel method which improves digital image stabilization performance using adoptive selection of motion estimation area. Candidate area for motion estimation is decided and through two processes, multi image reference and edge energy distinction, final motion estimation area is selected. Then Motion estimation and compensation is following in selected area. Experimental results show that proposed method improves performance of digital image stabilization.

Summer Vegetation Characteristic of Nature-like Stream Bank Stabilization (자연형 호안공법의 여름철 식생특성)

  • Lee, Kang-Suk;Park, Jin-Ki;Park, Jung-Haw;Yeon, Gyu-Bang
    • Proceedings of the Korea Water Resources Association Conference
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    • 2009.05a
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    • pp.2078-2082
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    • 2009
  • Riparian vegetation distribution patterns and diversity relative to various fluvial geomorphic channel patterns, stream bank stabilization methods, and stream flow processes are described and interpreted for selected stream of Goesan, Central Korea. Idong Stream Pilot Project, which began in May 2003 and finished in December 2003, was selected to develop effective methods. The project aim to maintain or increase stream bank stabilization ecosystem goods and services while protecting downstream and stream bank ecosystem. A number of protecting methods which are a Flight of fieldstone, Vegetation block, Green river block, Stone net, Green environment block, Eco friendly cobble, Vegetation mat and Geo green cell and Firefly block were applied on the bank of Idong stream. The stream sites have been monitored about flora conditions each method in 2007. We selected 12 points for summer seasons to separately investigate in left bank, right bank and river bed. The main purpose of this study was to find out suitable methods and to improve stream restoration techniques for ecosystem. On the stream bank, Eco friendly cobble method(9.57) was the highest average of vegetation cover and Firefly block method(3.87) was the lowest average in applied methods.

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