• Journal of the Korea Concrete Institute
• /
• v.15 no.4
• /
• pp.522-528
• /
• 2003

Concrete has been considered as a semi-permanent structural material, because its excellent durability. However, such high durable structure is often attacked by some environmental condition such as chloride diffusion, carbonation and so on. In order to prevent the deterioration behaviors of concrete structures. We estimated durability of concrete when used surface treatment system and coatings by new type inorganic coating materials. Base on the results of chloride ion's diffusion test, the coated cement mortar had smaller transmitted quantity.

• Computers and Concrete
• /
• v.14 no.3
• /
• pp.299-313
• /
• 2014

Effects of polypropylene (PP) fibers, steel fibers (SF) and hybrid on the properties of highstrength fiber reinforced self-consolidating concrete (HSFR-SCC) under different volume contents are investigated in this study. Comprehensive laboratory tests were conducted in order to evaluate both fresh and hardened properties of HSFR-SCC. Test results indicated that the fiber types and fiber contents greatly influenced concrete workability but it is possible to achieve self consolidating properties while adding the fiber types in concrete mixtures. Compressive strength, dynamic modulus of elasticity, and rigidity of concrete were affected by the addition as well as volume fraction of PP fibers. However, the properties of concrete were improved by the incorporation of SF. Splitting tensile and flexural strengths of concrete became increasingly less influenced by the inclusion of PP fibers and increasingly more influenced by the addition of SF. Besides, the inclusion of PP fibers resulted in the better efficiency in the improvement of toughness than SF. Furthermore, the inclusion of fibers did not have significant effect on the durability of the concrete. Results of electrical resistivity, chloride ion penetration and ultrasonic pulse velocity tests confirmed that HSFR-SCC had enough endurance against deterioration, lower chloride ion penetrability and minimum reinforcement corrosion rate.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.15 no.6
• /
• pp.67-80
• /
• 2011

This paper presents the results of shaking table tests on a 1:5 scale 10-story R.C. wall-type residential building model. The following conclusions are drawn based on the test results. (1) The model responded linear elastically under the excitations simulating an earthquake with a return period of 50 years, and showed a nonlinear response under the excitations simulating the design earthquake of Korea. (2) The model showed a significant strength drop under the maximum considered earthquake, with a return period of 2400 years. (3) The major portion of the resistance to lateral inertia forces came from the walls used for the elevator and stair case. (4) Finally, the damage and failure modes appear to be due to the flexural behavior of walls and slabs. A significant deterioration of stiffness and an elongation of the fundamental periods were observed under increased earthquake excitations.

• Archives of Craniofacial Surgery
• /
• v.21 no.5
• /
• pp.283-287
• /
• 2020

Background: Closed reduction is the standard treatment for nasal bone fractures, which are the most common type of facial bone fractures. We investigated the effect of closed reduction on quality of life. Methods: The 15-dimensional health-related quality of life survey was administered to 120 patients who underwent closed reduction under general anesthesia for nasal bone fractures from February 2018 to December 2019, on both the day after surgery and 3 months after surgery. Three months postoperatively, the presence or absence of five nasal symptoms (nose obstruction, snoring, pain, nasal secretions, and aesthetic dissatisfaction) was also evaluated. Results: The quality of life items that showed significant changes between immediately after surgery and 3 months postoperatively were breathing, sleeping, speech, excretion, and discomfort. Low scores were found at 3 months for breathing, sleeping, and distress. There were 31 patients (25.83%) with nose obstruction, 25 (20.83%) with snoring, 12 (10.00%), with pain, 11 (9.17%) with nasal secretions, and 29 (24.17%) with aesthetic dissatisfaction. Conclusion: Closed reduction affected patients' quality of life, although most aspects improved significantly after 3 months. However, it was not possible to rule out deterioration of quality of life due to complications and dissatisfaction after surgery.

• Korean Journal of Rural Living Science
• /
• v.7 no.2
• /
• pp.99-108
• /
• 1996

This study has intended to suggest fundamental data to develope and choose appropriate shoes for upland farming in order to prevent health deterioration of women workers and improve work effectiveness and reduce fatigue by wearing appropriate shoes. During 1995. 4. 28 - 5. 10, Fifty women workers in hot pepper farming were observed and major shoe types, which were rubber shoes, walking shoes, slippers, and rubber boots, were selected for the study. During 1995. 10. 9 - 31, two subjects were tested by wearing those shoes in the laboratory where the temperature was 24$\pm$1$^{\circ}C$ and relative humidity 50$\pm$5%RH. And the temperature & humidity on sole and in the shoes, the rectal temperature, skin temperature, blood pressure, pulse, lactate concentration of blood, Flickers' value and subjective sensation were measured. The results were as follows : 1. 84% of women workers mentioned that they need shoes improvement and the order of most frequent shoe types to be worn was rubber shoes, walking shoes, slippers, rubber boots. 2. The rate of women who were unsatisfied with shoes for upland farming is 38 percentages. The reason of unsatisfaction was that feet were in a sweat and alien substances were let into shoes. 3. The temperature & humidity on sole were the lowest in rubber boots during experiment(p＜0.01). 4. The relative humidity in the shoes was the highest in rubber boots by 90% and the lowest in walking shoes by 72% during rest And the humidity in slippers and walking shoes were significantly low in experiment(p＜0.001). 5. Rubber boots showed the highest rise in rectal temperature by 0.2$^{\circ}C$ showing increase of core temperature (p＜0.05). 6. The mean skin temperature during experiment was highest in rubber boots by 33.8$^{\circ}C$(p＜0.001).

• Journal of Korean Neurosurgical Society
• /
• v.46 no.4
• /
• pp.300-304
• /
• 2009

Objective : This is retrospective study of clinical and radiological outcomes of anterior cervical fusion using Bongros-$HA^{TM}$ (BioAlpha, Seongnam, Korea) which is a type of synthetic hydroxyapatite (HA) spacer to evaluate the efficacy in its clinical application and usefulness as a reliable alternative to autograft bone. Methods : Twenty-nine patients were enrolled in this study and 40 segments were involved. All patients were performed anterior cervical interbody fusion using HA spacer and plating system. Indications for surgery were radiculopathy caused by soft-disc herniation or spondylosis in 18 patients, spondylotic myelopathy in 1 patient, and spinal trauma in 10 patients. Cervical spine radiographs were obtained on postoperative 1day, 1week, and then at 1, 2, 6, and 12 months in all patients to evaluate intervertebral disc height, and the degrees of lordosis. Cervical computed tomography was done at postoperative 12 month in all patients to confirm the fusion status. The mean period of clinical follow-up was 17 months. Results : Complete interbody fusion was achieved in 100% of patients. Preoperative kyphotic deformities were corrected in all cases after surgery. Intervertebral disc height was well maintained during follow up period. There were no cases of graft extrusion, graft deterioration and graft fracture. Conclusion : HA spacer is very efficient in achieving cervical fusion, maintaining intervertebral disc height, and restoring lordosis. When combined with the placement of a cervical plate, immediate stability can be achieved and graft related complication can be prevented.

• Journal of Korean Neurosurgical Society
• /
• v.56 no.1
• /
• pp.28-33
• /
• 2014

Objective : Postoperative delirium is a common complication in the elderly after surgery but few papers have reported after spinal surgery. We analyzed various risk factors for postoperative delirium after spine surgery. Methods : Between May 2012 and September 2013, 70 patients over 60 years of age were examined. The patients were divided into two groups : Group A with delirium and Group B without delirium. Cognitive function was examined with the Mini-Mental State Examination-Korea (MMSE-K), Clinical Dementia Rating (CDR) and Global Deterioration Scale (GDS). Information was also obtained on the patients' education level, underlying diseases, duration of hospital stay and laboratory findings. Intraoperative assessment included Bispectral index (BIS), type of surgery or anesthesia, blood pressure, fluid balance, estimated blood loss and duration of surgery. Results : Postoperative delirium developed in 17 patients. The preoperative scores for the MMSE, CDR, and GDS in Group A were $19.1{\pm}5.4$, $0.9{\pm}0.6$, and $3.3{\pm}1.1$. These were significantly lower than those of Group B ($25.6{\pm}3.4$, $0.5{\pm}0.2$, and $2.1{\pm}0.7$) (p<0.05). BIS was lower in Group A ($30.2{\pm}6.8$ compared to $35.4{\pm}5.6$ in group B) (p<0.05). The number of BIS <40 were $5.1{\pm}3.1$ times in Group A, $2.5{\pm}2.2$ times in Group B (p<0.01). In addition, longer operation time and longer hospital stay were risk factors. Conclusion : Precise analysis of risk factors for postoperative delirium seems to be more important in spinal surgery because the surgery is not usually expected to have an effect on brain function. Although no risk factors specific to spinal surgery were identified, the BIS may represent a valuable new intraoperative predictor of the risk of delirium.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2017.05a
• /
• pp.238-239
• /
• 2017

Waterproofing is a very important process in terms of durability of buildings. The materials used for waterproofing work to protect the concrete structure from external deterioration factors. In particular, the waterproofing materials applied to the exterior of the concrete structure have various problems due to changes in the external environment and variables in the construction process. The waterproof layer is repeatedly dried and shrunk according to changes in the external moisture environment, and the surface may be deteriorated due to exposure to long-term sunlight. In the case of the roof waterproofing in the structure, the waterproof layer which does not have a sufficient curing period shows much swelling and floating phenomenon. These defects, such as swelling and lifting, account for most of the defects that occur in the waterproof layer of the concrete slabs. Generally, it is difficult to expect the same level of performance as the initial state even if the waterproofing work is repaired when a defect occurs. Therefore, it is possible to reduce the defects of the waterproof layer such as swelling and lifting by forming a waterproof layer which can be integrated with the concrete surface by using a polyurethane type waterproofing material having a relatively low defective ratio compared to other waterproofing materials. So in this study, the basic properties of polyurethane waterproof sheet reinforced with non-woven fabric are investigated in order to understand field applicability.

• KIEAE Journal
• /
• v.12 no.1
• /
• pp.3-10
• /
• 2012

Recently, the increase of impervious area has been pointed out as a major cause of climate change and biotop area deterioration]. Therefore, quantitative indicators for environmental housing design and planning have been needed especially to control the impervious area. The Biotop Area Ratio(BAR) as the mostly applied environmental planning control instrument in Korea verifying the possibility of utilizing has been used effectively in various aspects. However, the fact that the space types are based on two dimension and ecological functions of spaces are simplified has shown the limitations of this planning instrument in the use as planning and evaluation indicator. In this study, classification criteria and the weighting of the space types in similar indicators Biotopflaechenfaktor (BFF, Berlin), Seattle Green Factor (SGF, Seattle), and Green Area Factor (GAF, Malmo) were analyzed. These indicators are similar in the sense that they apply weights to calculate the area and express a percentage of land area. The findings are as follows: The basic method that can estimate the vegetation volume is proposed to overcome the limitation of the BAR. It also was proven that the introduction of three-dimensional volume rate of biotops area was possible. Finally, the framework of space type classification criteria is proposed through linkages with relevant laws and regulations. With the improvement of the space types, the BAR is expected to be reasonable indicator in outdoor space evaluation in housing project.

• Korean Institute of Interior Design Journal
• /
• v.22 no.5
• /
• pp.258-266
• /
• 2013

Rapidly aging society extends the span of aged life of the elderly people longer than before and this trend raises the issue of holistic health of the aged including their physical, psychological and social health making it necessary to study for environmental development to support this trend. This study intends to explore the direction of residential planning to support the deterioration phenomenon of social networks due to aging. Social networks here are treated as basic conditions for social health. This study researched the diverse types of elderly housings in preparation for the aged society and their spatial characteristics, social affordance characteristics and their potentials for social interactions from the viewpoint of their social relations. literature studies with contents analysis method was used. The results of this study were arranged primarily according to the characteristics of social relations by types of housings. Socially integrated types of housings can be found as inclusive housing type as they have both social characteristics that can be found in houses in general and the elderly housings, they should be considered as desirable types in Korea where collective houses are most popular. Form the existing housing plans housing plan direction should move toward socially integrated housing plans that can protect the elderly people collectively and the direction of housing plans here means the direction from more macro-perspective viewpoint. Therefore, the results of this study are meaningful in adding interpretation from the viewpoint of social relations respective housings and promoting housings for the elderly people more desirably.