• Title/Summary/Keyword: Deterioration factors

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The Effects of COVID-19 Pandemic on the Recovery of Hip Fracture Patients

  • Young Yool Chung;Sung Nyun Baek;Tae Gyu Park;Min Young Kim
    • Hip & pelvis
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    • v.35 no.4
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    • pp.253-258
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    • 2023
  • Purpose: To figure out how complete control of family visits to prevent infection of coronavirus disease 2019 (COVID-19) affected the activity recovery of hip fracture patients admitted to nursing hospitals. Materials and Methods: Eighty-one patients with hip surgery in the two years prior to COVID-19 pandemic were classified as Group A, and 103 patients in the next two years were designated as Group B. The subjects' walking ability was evaluated by using the modified Koval index (MKI). In order to analyze the impact of the family visit control to the subjects, each group was classified into two different groups: (1) inpatients group who admitted to nursing hospitals and (2) home-treated patients. Additionally, statistical elements were processed in consideration of other factors that may affect the results of the experiment. Results: The MKI evaluated at 6 months postoperative was 3.31±1.79 in Group A and 2.77±1.91 in Group B, and it was meaningfully low after the pandemic (P=0.04). There was significantly low among both of Group A 2.74±1.76 and Group B 1.93±1.81 after the pandemic (P=0.03) among those treated at the nursing hospital. The rate of deterioration of the MKI was 35 (43.2%) in Group A and 57 (55.3%) in Group B, which increased by 12.1% after the pandemic. Conclusion: The pandemic had a negative effect on the recovery of postoperative activities of elderly hip fracture patients who admitted to nursing hospitals when family access was completely restricted to prevent infection.

A study on the deterioration phenomenon of stored rice during the decomposition process of polysaccharide carbohydrates (다당류 탄수화물의 분해과정을 통한 보관 벼의 감모현상에 관한 연구)

  • Yong-Sik Youn;Jae-Min An;Wang-Taek Hwang;Hyungmin Roh;Hae-Min Park;Kyeongseok Oh
    • Journal of Applied Biological Chemistry
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    • v.66
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    • pp.289-298
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    • 2023
  • Stored rice grain undergoes physical and chemical deteriorations over time. As temperature and moisture content are important factors affecting to the denaturation of rice, it is important to store rice at a low temperature and hermetic condition. From a microscopic point of view, many studies have already reported how proteins and lipids were denatured within rice grain. Meanwhile, the weight loss of rice is currently observed at actual storage sites and can occur for diverse reasons. In this study, it was assumed that the decomposition process of polysaccharides, known as the main component of rice, plays an important role in its weight loss. In specific, the roles of enzymes were also evaluated. Our interest is in the major polysaccharides within a rice grain such as starch as well as within a rice endosperm cell wall. It is suspected that the weight loss of rice grains during storage seems to associate with the degradation of amylose and amylopectin. Nevertheless, it should be also speculated the correlating effect of other components such as proteins and lipids.

Review of the Current infrared Thermorgraphy Techniques for Detecting Defects in Civil Structures (토목 구조물의 손상 검출을 위한 적외선 열화상 기법의 적용 사례 분석)

  • Sim, Jungi;Zi, Goangseup;Park, Jin-Hyung;Cho, Hyo-Nam;Lee, Jong Seh
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.3
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    • pp.71-83
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    • 2008
  • In this paper, the basic principle, the application and the limitation of Infrared thermography technique to detect defects in different kinds of concrete structures are reviewed. Considered are voids beneath the concrete surface with experiments, delamination between concrete surface and fiber reinforced polymer sheet, the deterioration of steel bars in reinforced concrete, surface defects in historical buildings, pavements, bridges, and railway track graves. As a result, we conclude that infrared thermography methods are useful for fast detecting defects; however, they are influenced by environmental factors, specially temperature. Therefore it is recommended to use the infrared thermography technique with other NDT equipments to expect better result.

A Study on Corrosion Potential of Cracked Concrete Beam According to Corrosion Resistance Assessment (부식 저항성 평가에 따른 균열 콘크리트 보의 부식전위 연구)

  • Song, Ha-Won;Lee, Chang-Hong;Lee, Kewn-Chu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.1 s.53
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    • pp.97-105
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    • 2009
  • Development and use of blended cement concrete is gaining more importance in the construction industry with reference to durability mainly due to the pore refinement and reduction in permeability. Cracks play a major role on important parameters like permeability, rate of chloride ingress, compressive strength and thus affect the reinforcement corrosion protection. Furthermore, when a crack occurs in the cover concrete, the corrosion of the steel reinforcement may be accelerated because the deterioration causing factors can pass through the crack. In recent years the effect of cracking on the penetration of concrete has been the subject of numerous investigations. Therefore assessing the service life using blended concrete becomes obviously in considering the durability. In the present study, the corrosion assessment of composite concrete beams with and without crack with of 0.3mm using OPC, 30% PFA, 60% GGBS, 10% SF was performed using half cell potential measurement, galvanic potential measurement, mass loss of steel over a period of 60days under marine environmental conditions and the results were discussed in detail.

Real-Time Video Quality Assessment of Video Communication Systems (비디오 통신 시스템의 실시간 비디오 품질 측정 방법)

  • Kim, Byoung-Yong;Lee, Seon-Oh;Jung, Kwang-Su;Sim, Dong-Gyu;Lee, Soo-Youn
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.3
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    • pp.75-88
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    • 2009
  • This paper presents a video quality assessment method based on quality degradation factors of real-time multimedia streaming services. The video quality degradation is caused by video source compression and network states. In this paper, we propose a blocky metric on an image domain to measure quality degradation by video compression. In this paper, the proposed boundary strength index for the blocky metric is defined by ratio of the variation of two pixel values adjacent to $8{\times}8$ block boundary and the average variation at several pixels adjacent to the two boundary pixels. On the other hand, unnatural image movement caused by network performance deterioration such as jitter and delay factors can be observed. In this paper, a temporal-Jerkiness measurement method is proposed by computing statistics of luminance differences between consecutive frames and play-time intervals between frames. The proposed final Perceptual Video Quality Metric (PVQM) is proposed by consolidating both blocking strength and temporal-jerkiness. To evaluate performance of the proposed algorithm, the accuracy of the proposed algorithm is compared with Difference of Mean Opinion Score (DMOS) based on human visual system.

Evaluation of Adhesion Characteristics of Crack Sealants Used in Asphalt Concrete Pavement (아스팔트 콘크리트 포장용 균열실링재의 부착특성 평가)

  • Lee, Jae-Jun;Kim, Seung-Hoon;Baek, Jong-Eun;Lim, Jae-Kyu;Kim, Yong-Joo
    • International Journal of Highway Engineering
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    • v.17 no.2
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    • pp.55-62
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    • 2015
  • Cracking is an inevitable fact of asphalt concrete pavements and plays a major role in pavement deterioration. Pavement cracking is one of the main factors determining the frequency and method of repair. Cracks can be treated with a number of preventative maintenance actions, including overlay surface treatments such as slurry sealing, crack sealing, or crack filling. Pavement cracks can show up as one or all of the following types: transverse, longitudinal, fatigue, block, reflective, edge, and slippage. Crack sealing is a frequently used pavement maintenance treatment because it significantly extends the pavement service life. However, crack sealant often fails prematurely due to a loss of adhesion. Because current test methods are mostly empirical and only provide a qualitative measure of the bond strength, they cannot accurately predict the adhesive failure of the sealant. This study introduces a laboratory test aimed at assessing the bonding of hot-poured crack sealant to the walls of pavement cracks. A pneumatic adhesion tensile testing instrument (PATTI) was adopted to measure the bonding strength of the hot-poured crack sealant as a function of the curing time and temperature. Based on a limited number of test results, the hot-poured crack sealants have very different bonding performances. Therefore, this test method can be proposed as part of a newly developed performance-based standard specification for hot-poured crack sealants for use in the future. PURPOSES : The purpose of this study was to evaluate both the adhesion and failure performance of a crack sealant as a function of its curing time and curing temperature. METHODS: A pneumatic adhesion tensile testing instrument (PATTI) was adopted to measure the adhesion performance of a crack sealant as a function of the curing time and curing temperature. RESULTS: With changes in the curing time, curing temperature, and sealant type, the bond strengths were found to be significantly different. Also, higher bond strengths were measured at lower temperatures. Different sealant types produced completely different bond strengths and failure behaviors. CONCLUSIONS: The bonding strength of an evaluated crack sealant was shown to differ depending on various factors. Two sealant types, which were composed of different raw materials, were shown to perform differently. The newly proposed test offers the possibility of evaluating and differentiating between different crack sealants. Based on alimited number of test results, this test method can be proposed as part of a newly developed performance-based standard specification for crack sealants or as part of a guideline for the selection of hot-poured crack sealant in the future.

Evaluation of the Elderly Gait Stability Using the Center of Mass and Center of Pressure Inclination Angles (전, 후방 기울기각을 이용한 노인의 보행안정성 평가)

  • Yoon, Suk-Hoon;Kim, Tae-Sam;Lee, Jae-Hun;Ryu, Ji-Seon;Kwon, Young-Hoo
    • Korean Journal of Applied Biomechanics
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    • v.17 no.4
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    • pp.99-106
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    • 2007
  • The gait instability in the elderly has been associated with age-related deterioration in physical strength and reducing the potential for elderly falls requires regular exercise. In 2005, National Center for Injury Prevention and Control(NCIPC) reported that most elderly falls occur during activities in daily living(ADL). To better reveal biomechanic mechanisms underlying age-related degeneration in gait stability, and to enhance the assessment of falls risk, an accurate quantification of a person's balance maintenance during locomotion is needed. Instantaneous orientation of the line connecting COP and COM can characterize whole body position with respect to the supporting foot during gait and the angle between this line and the vertical line passing through the COP known as a good assessment to detect the elderly gait instability. Therefore the purpose of this study was to investigate a 6-month walking exercise effects in reducing elderly fall risk factors by using COP-COM inclination angles. Twenty-two community-dwelling elderly participated this study. The participants performed a walking exercise(3 times/week, 1 hour/visit) for 6 months. Laboratory kinematics during walking was assessed at months 0, 3 and 6. Significant increased in gait velocity was found among periods(p=.011, $1.25{\pm}.03$, $1.32{\pm}.03$, and $1.39{\pm}.04\;m/s$ in 0-, 3-, and 6-month, respectively). Also, significant differences in anterior and posteriror inclination angles were found among the periods(p<.05; posterior inclination angles: $12.8{\pm}2.2$, $11.0{\pm}2.9$, & $10.9{\pm}1.9$; anterior inclination angles: $13.7{\pm}1.7$, $14.6{\pm}3.2$, & $1.46{\pm}.21$ in 0month, 3month, & 6month, respectively). These findings provide evidence of significant reduced fall risk factors of community-living older adults associated with a systematic walking program.

Associated factors of self-reported dry mouth in adults (일부 성인의 주관적 구강건조증에 영향을 미치는 요인)

  • Kim, Sun-Sook;Youn, Hye-Jeong
    • Journal of Korean society of Dental Hygiene
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    • v.15 no.1
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    • pp.55-62
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    • 2015
  • Objectives: The purpose of this study was to investigate the associated factors of self-reported dry mouth in adults. Methods: A self-reported questionnaire was filled out by 249 adults in Seoul and Gyeonggi-do from June to October, 2014. The questionnaire consisted of general characteristics of the subjects, age, monthly income, smoking, alcohol drinking, and systemic diseases including systemic diseases, medication, oral health status, and stress. The question for dry mouth consisted of dryness in skin, eyes, lips, and nasal mucosa. The subjective dry mouth consisted of 6 questions measured by visual analogue scale(VAS). Cronbach's alpha was 0.881 in the study. Oral health related quality of life (OHIP-14) was adapted from Yoon. The questionnaire for OHIP-14 included functional limitation, physical pain, psychological disability, social disability, and experience in hadicap measured by Likert 5 scale. Cronbach's alpha was 0.885 in the study. Data was analyzed for a t-test, one-way ANOVA and multiple regression analysis by using SPSS(SPSS 18.0, USA) program. Results: There were positive correlations between oral health-related quality of life and self-reported dry mouth (functional limitation r=0.288, physical pain r=0.219, psychological discomfort r=0.193, physical disability r=0.280, psychological disability r=0.205, social disability r=0.224 and handicap r=0.270). In the multiple regression analysis, variation of self-reported dry mouth were positively associated with dry eyes{very often(${\beta}=0.305$)), sometimes(${\beta}=0.186$)}, dryness on lips{very often(${\beta}=0.247$), sometimes(${\beta}=0.177$)}, handicap(${\beta}=0.152$), physical disability(${\beta}=0.128$) and alcohol drinking(1-2 times/week)(${\beta}=0.116$) (p<0.001). Conclusions: Self-reported dry mouth may cause deterioration of the entire body dryness(dryness on eyes and lips), low oral health-related quality of life(handicap and physical disability) and alcohol drinking. Thus, It is necessary to develop oral health education programs to prevent and manage dry mouth in adults.

Measurement Method of Final Residual Radioactivity of Radioactive Metallic Waste for Clearance (규제해제 대상 방사성 금속 폐기물 최종잔류방사능 측정법)

  • Seo, Bumkyoung;Ji, Youngyong;Hong, Sangbum;Lee, Keunwoo;Moon, Jeikwon
    • Journal of Radiation Protection and Research
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    • v.38 no.4
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    • pp.228-233
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    • 2013
  • It has been continuously generated the requirement for the replacement of the main components such as a steam generator due to the deterioration of the nuclear power plant all around the world. Also, a large amount of radioactive metal was generated during the decommissioning in a short period. It is required to make an accurate measurement of the residual radioactivity for recycling the metal waste for releasing from regulatory control. In planning the measurement procedures, the influence of geometry, self-absorption, density and other relevant factors on the representativeness of the measurements should be considered for the decommissioning metal waste. In this study, the method for measurement procedures, the source term evaluation, the ways to secure representative samples, the measurement device for wide area and the self-absorption correction factors for different density were evaluated. The metal samples for measurement were prepared for securing the simple geometry and representative by melting process. The developed correction method for measuring the radioactivity a variety density of metal waste could improve the reliability of the evaluation results for clearance.

Improvement of Sediment Trapping Efficiency Module in SWAT using VFSMOD-W Model (VFSMOD-W 모형을 이용한 SWAT 모형의 초생대 유사 저감 효율 모듈 개선)

  • Park, Younshik;Kim, Jonggun;Kim, Namwon;Park, Joonho;Jang, Won-Seok;Choi, Joongdae;Lim, Kyoung Jae
    • Journal of Korean Society on Water Environment
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    • v.24 no.4
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    • pp.473-479
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    • 2008
  • Environment problem has been arising in many countries. Especially, soil erosion has been deemed as one of the biggest issues because sediment causes muddy water and pollutants, such as agricultural chemicals, flow in the stream with this sediment. Many studies, regarding soil loss and non-point source pollution from watershed, has been performed while serious problem has been known. Soil loss occurred in most agricultural area by rainfall and runoff. It makes hydraulic structure unstable, causes environmental economical problems because muddy water destroys ecosystem and causes intake water deterioration. As revealing serious effects of muddy water by sediment, many researches have been doing with various methods. Hydraulic structures establishments such as soil erosion control dams and grit chamber are common. Vegetative filter strip is investigated in this study because vegetative filter strip is designed for reducing sediment from upland areas of the watershed, and it has many functions, not only sediment reduction but also runoff water quality improvement and wildlife habitat. With these positive functions of the vegetative filter strip, the study about vegetative filter strip has been increasing for reducing sediment because it is more effective than hydraulic structures from an environmental perspective. But the sediment trapping efficiency by vegetative filter strip, needs to be investigated and designed first. Therefore the model, VFSMOD-W, was used in this study as it can estimate sediment trapping efficiency of vegetative filter strip under various field, vegetation, weather condition. Sensitive factors to sediment trapping efficiency are studied with VFSMOD-W, and sediment trapping efficiency equation has been derived using two most sensitive factors. It is thought that the equation suggested in this study can be used in Soil and Water Assessment Tool (SWAT), to overcome the limit of SWAT filter strip module, which is based solely on filter strip width.