• The Journal of the Korean dental association
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• v.37 no.4 s.359
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• pp.287-293
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• 1999

Long-term posttreatment stability is great concern to all orthodontist. So, this article was disussed that etiology of relapse, classificatioan of retention, duration of retention and treat after relapse. The most important thing about stability was considered that growth pattern, periodontal remodeling, neuromuscular factors and applied the appropriate mechanotherapy. Retenton was considered during the treatment planning and required considerable analytic thought.

• The Journal of Engineering Geology
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• v.16 no.1 s.47
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• pp.45-58
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• 2006

A new computer program SLOPILE(Ver 3.0) is developed to analyze stability of slopes containing an earth retention system composing of piles, nails and anchors. SLOPILE(Ver 3.0) can calculate the slope stability for both planar failure surfaces in infinite slopes and arc failure surfaces. In order to investigate a design adaptability of SLOPILE(Ver 3.0), analysis results of TALREN and SLOPE/W programs are compared with that of SLOPILE(Ver 3.0). SLOPILE(Ver 3.0) can calculate the slopes reinforced by earth retention system such as piles, nails and anchors. But, TALREN and SLOPE/W can not calculate the slope reinforced by piles. As a analysis result of the example case, SLOPILE(Ver 3.0) is accuracy and suitable program for the stability analysis of slopes reinforced by earth retention system. Therefore, SLOPILE(Ver 3.0) is the most suitable program to analyze the slope reinforced by the earth retention system.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.57-64
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• 2004

In order to establish the design method of anchored retention walls in cut slope, the behavior of anchored retention walls and backside ground needs to be investigated and checked in detail. In this study, the behavior of anchored retention walls was investigated by instrumentation installed in cut slope for an apartment construction site stabilized by a row of piles and anchored retention walls. When the anchor was installed at each excavating stages, the horizontal deflection of retention wall decreased, while the horizontal deformation of backside ground increased. The deflection of anchored retention wall decreased as the anchor was prestressed. The prestressed anchor farce has a great effect on the deflection of retention walls, while it has little effect on the deformation of its backside ground. The maximum horizontal deflection of anchored retention walls was developed between $1\%\;and\;4\%$ of excavation depth, which are $2\~8$ times larger than max. horizontal deflection of anchored retention walls including rock layers with backside horizontal ground. Meanwhile, SLOPILE (ver. 3.0) program analyzes the slope stability effects for anchored retention walls. As a result of analysis on slope stability analysis, the lateral earth pressure applied at anchored retention piles could be used as the mean values of empirical lateral pressures using anchored retention wall with horizontal ground at its backside.

• Journal of Marine Bioscience and Biotechnology
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• v.11 no.2
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• pp.89-93
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• 2019

In this study, the stability of the extracted natural pigments against light, temperature, pH, metal ions, and antimicrobial activity were evaluated in marine bacteria Zooshikella sp. 17TA. The pigment of the strain used in the study was red with maximum absorption at a wavelength of 541 nm. The stability of the pigment was evaluated by measuring the absorbance while preserving for 15 days and examining the retention rate. After 15 days of irradiation, the pigment of this bacterium showed 98% retention in the dark and 91% retention in the temperature range of -20℃ ~ 30℃. When the pH was in the range 4-7, the retention was about 80%, and the retention rate was higher than 85% for all kinds of metal ions except for CuCl₂, ZnCl₂, and KCl. The bacterial pigments showed high stability under the given irradiated pH, temperature, and metal ion conditions and had shown activity against gram-positive strains. These results suggest that this highly conserved microbial pigment can be applied to the food industry.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.2
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• pp.107-112
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• 2001

The prosthodontic treatment of severely resorbed edentulous patients has been one of the frustrating areas due to extensive loss of tissues. The integrated neuromuscular balance among tongue, lip, and cheek is compromised. The retention, stability, and support are the three major factors to influence the clinical outcome. Fish described a denture as having three surface, with each surface playing an independent and important role in the over all fit, stability, and comfort of the denture. He recommended that the polished surface should be a series of inclines so that pressure from muscular activity will retain dentures. Within the denture space there is an area that has been termed the neutral zone. The neutral zone is that area in the mouth where, during function, the forces of the tongue pressing outward are neutralized by the forces of the cheeks and lips pressing inward. According to Jacobson and Krol, neuromuscular control interacts to provide retention and the relationship of polished surface of denture base to the surrounding muscular structure of orofacial capsule facilitates the stability and retention. This neutral zone concept has been demonstrated with various modification by a number of authors. The theory used to develop the denture base contours is based on the belief that the muscle should functionally mold not only the border but the entire polished surface. Lott and Walsh reported the clinical success on complete mandibular dentures with application of neutral zone concept. A number of studies demonstrated that denture stability and retention are more dependent on correct position of the teeth and correct contour of external surfaces of the denture in a severely resorbed alveolar ridge. This article presents a prosthodontic approach to treatment of a edentulous patient using neutral zone technique to improve the retention and stability of the prosthesis.

• Geomechanics and Engineering
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• v.33 no.2
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• pp.141-154
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• 2023

This study investigated the effect of water retention characteristics between aged and fresh Municipal Solid Waste (MSW) on the stability of the landfill. A series of transient numerical modeling for the slope of an MSW landfill was performed considering the variation of water retention characteristics due to leachate circulation. Four different scenarios were considered in this analysis depending on how to obtain hydraulic conductivity and the aging degree of materials. Unsaturated hydraulic properties of the MSW used for the modeling were evaluated through modified hanging column tests. Different water retention properties and various landfill conditions, such as subgrade stiffness, leachate injection frequency, and gas and leachate collection system, were considered to investigate the pore water distribution and slope stability. The stability analyses related to the factor of safety showed that unsaturated properties under those varied conditions significantly impacted the slope stability, where the factor of safety decreased, ranging between 9.4 and 22%. The aged materials resulted in a higher factor of safety than fresh materials; however, after 1000 days, the factor of safety decreased by around 10.6% due to pore pressure buildup. The analysis results indicated that using fresh materials yielded higher factor of safety values. The landfill subgrade was found to have a significant impact on the factor of safety, which resulted in an average of 34% lower factor of safety in soft subgrades. The results also revealed that a failed leachate collection system (e.g., clogging) could result in landfill failure (factor of safety < 1) after around 298 days, while the leachate recirculation frequency has no critical impact on stability. In addition, the accumulation of gas pressure within the waste body resulted in factor of safety reductions as high as 24%. It is essential to consider factors related to the unsaturated hydraulic properties in designing a landfill to prevent landfill instability.

• Geomechanics and Engineering
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• v.28 no.1
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• pp.77-87
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• 2022

Many geotechnical analyses require the investigation of water flow within partially saturated soil zone to incorporate the effect of climatic conditions. It is widely understood that the hydraulic properties of the partially saturated soil should be included in the transient seepage analyses. However, the characteristics of dual porosity soils with dual-mode water retention curve are normally modelled using single-mode mathematical equation for simplification of the analysis. In reality, the rainwater flow can be affected significantly by the dual-mode hydraulic properties of the soil. This paper presents the variations of safety factor for dual porosity soil slope with dual-mode water retention curve and dual-mode unsaturated permeability. This paper includes the development of the new dual-mode unsaturated permeability to represent the characteristics of soil with the dual-mode water retention curve. The finite element analyses were conducted to examine the role of dual-mode water retention curve and dual-mode unsaturated permeability on the variations of safety factor under rainfall loading. The results indicate that the safety factor variations of dual porosity soil slope modelled using the dual-mode water retention curve and the unsaturated permeability equation are lower than those of dual porosity slope modelled using single-mode water retention curve and unsaturated permeability equations.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.2
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• pp.18-25
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• 2003

The adsorption of co-cationic dual polymer system was investigated as was the fiber dispersion stability of a paper stock suspension. Polyaluminum chloride(PAC) and polyamidoamine epichlorohy-drin(PAE) polymers were used as wet-end additives. The adsorbed amounts of PAE polymer in a wet stock were measured by using polyelectrolytic PCD titration. The sheet forming experiments were carried out in a standard handsheet machine. Fiber dispersion stability and relative retention were evaluated in terms of M/K non-uniformity index and sheet basis weight, respectively. The PAE polymer adsorption of Langmuir-isothermal type decreased with increasing PAC addition level. The combination of the two cationic polymers presumably exerts a site-blocking effect by the low molecular weight PAC which gives a partial charge neutralization at a minimum level of addition. From a thermodynamic view point of PAE adsorption, an increase in adsorption entropy and a decrease in train number suggests that the PAR polymer has an extended conformation structure that potentially leads to an enhancement of the fiber dispersion stability. This conclusion is supported by handsheet experiments that examined the PAC-PAE dual polymer effects on the sheet formation and retention.

• Journal of Home Health Care Nursing
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• v.26 no.3
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• pp.319-328
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• 2019

Purpose: The purpose of this study was to establish baseline data for the development of employment policies to improve the efficiency and stability of visiting healthcare services. It identifies factors affecting visiting nurses' intention-to-retention at healthcare centers in Seoul. Methods: This descriptive study investigated subjective health perception, job stress, professionalism, job satisfaction, and intention-to-retention of 269 nurses with more than one year of work experience as a visiting nurse. These factors were analyzed using t-tests, chi-square, partial correlation, and stepwise multiple regression. Results: The results indicate that satisfaction for professional status in job satisfaction, educational level, autonomy in professionalism, and visiting nursing career were significant factors that impacted the retention of visiting nurses. Conclusion: It is necessary to frame policies and provide support to enhance the satisfaction and autonomy for visiting nurse as a profession for the efficiency and stability of visiting healthcare services.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.1-7
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• 2008

The trend of using more hardwood and recycled fibers, and closing more tightly of the paper mill white water system has resulted in build-up of fines as well as organic and inorganic contaminants in the white water. This changes in papermaking wet end requires developing chemical additive system that provides good fiber retention and drainage in closed white water system. In this study the effect of charge densities and chemical characteristics of microparticle systems consisted of cationic guar gums and anionic colloidal silica sols on drainage and retention have been examined. Results showed that higher charge density of cationic guar gum and anionic colloidal silica sol gave better retention and drainage. Particularly highly structured silica gave greater retention efficiency.