• 한국주거학회논문집
• /
• 제19권2호
• /
• pp.31-42
• /
• 2008

Research outcome shows the following: 1. Estimation by the year 2015 on the number of the aged people and on the number of the household of living alone and living with spouse only, per age-cohort by 5 years, per basic self-govern-ins local groups and the city of Daegu. The result is supposed to serve as meaningful basic material in building up future policies in many areas for the aged people living in their homes. 2. Estimation varies according to the areas and the age-cohorts. In urban areas, increase of the numbers of the households of the aged people living alone and living with spouse only is estimated in every age-cohort. In rural areas, variance between two age-groups, old-old and young-old, is observed. Both of the numbers of the households for the aged living alone and the aged living with spouse only have increased continuously by the year 2005. But the hither-to increase tendency is estimated to reverse itself to a decrease starting from the younger within the young-old age group, and the ratio of the old-old age-group in rural population will sharply increase starting from the year 2005. Such increase in the number of the aged people in need of the housing and the social support requires the increasing policy consideration for the issue of housing for the aged living in their homes. In spite of the decreasing tendency in the number of the aged people living alone and living with spouse only in rural areas, still there will continue to be more number of such households than in urban area for the time being. The government of Gyeongsangbuk-Do should pay more consideration to the old-old aged living alone and living with spouse only in rural areas, while being prepared for the sharply increasing households for the aged living alone and living with spouse only in urban areas.

• Safety and Health at Work
• /
• 제15권2호
• /
• pp.158-163
• /
• 2024

Objectives: The present paper aimed to examine whether an aging workforce is associated with an increase in work-related fatal injuries and to explore the underlying reasons for this potential increase. Material and methods: Aged workers were defined as those who were at least 55 years old. Work-related fatalities were assessed in aged and young workers who were registered with the workers' compensation system in 2021 in the Republic of Korea. Total waged workers, based on raw data from the Local Area Labor Force Survey in 2021, were used as the denominator to estimate the work-related fatality rates. Results: Most work-related fatalities in the aged workers occurred among individuals working in the "construction sector" (58.9%), those with "elementary occupations (unskilled workers)" (46.1%), and those with the employment status of "daily worker" (60.8%). The estimated incidence (0.973/10,000) of work-related fatalities among aged workers was about four times higher than that (0.239/10,000) among younger workers. "Falling," "collision," "struck by an object," and "trip and slip" were more frequent types of work-related fatalities among aged workers relative to young workers. The category of "buildings, structures, and surfaces" was a more frequent cause of work-related fatalities among aged workers than among young workers. Conclusions: Aged workers had a higher incidence of work-related fatalities than young workers. Frequent engagement in precarious employment and jobs, coupled with the greater physical vulnerability of aged workers, were likely causes of their higher level of work-related fatal injuries.

• 한국건설관리학회논문집
• /
• 제8권2호
• /
• pp.118-126
• /
• 2007

최근 친환경건축물인증제도, 주택성능등급표시제도를 비롯하여 실내공기환경에 대한 기준, 친환경상품인증기준 등 환경관련 제도 및 규정이 마련되면서 공동주택의 신축 및 리모델링 공사에 이에 대한 고려가 필요한 상황이다. 특히 공동주택 리모델링 공사는 거주자가 사전에 정해진 상태에서 공사를 진행하므로 이들에 대한 의견수렴과 사용되는 소재에 대한 요구분석이 신축에 비해 중요하다는 특성이 있다. 하지만 현재 국내에서 시행 중에 있거나 최근 완료된 리모델링 공사의 시공자는 친환경 소재 적용에 대한 거주자의 적극적인 의견수렴 과정이 미비하였고, 친환경상품인증원의 최우수 등급을 받은 친환경 제품을 거주자의 요구에 의해 적용한다기 보다는 공동주택의 홍보의 일환으로 사용하고 있는 실정이었다. 또한 공동주택 리모델링 거주자는 친환경 제품의 인증기준에 대한 이해가 부족하여 친환경 제품의 등급을 맹목적으로 신뢰하는 경우가 있었고 적용되는 친환경 소재에 대한 요구가 매우 정성적인 특징이 있다. 따라서 공동주택 리모델링 거주자의 친환경 소재에 대한 요구사항을 조사하고 이를 정량적으로 분석하여 만족도를 극대화 할 수 있는 친환경 소재를 리모델링 공사에 적용하여야 한다.

• Transactions on Electrical and Electronic Materials
• /
• 제9권4호
• /
• pp.147-150
• /
• 2008

Porcelain suspension insulators aged for 1, 5 and 10 years on Korean transmission lines and new insulators are tested for autoclave expansion. The compressive strength of the insulators aged in an autoclave with conditions of $250\;^{\circ}C$ and at 20 atm for 30 minutes, was about $7.6\;kgf/mm^2$, which is close to that measured on insulators aged for 10 years in the field. From simulation results, the cement displacement changed linearly with temperature. At a temperature of $200\;^{\circ}C$, the shear stress was approximately $7\;kgf/mm^2$; a stress that is brought about by a 0.07 % expansion of the cement. It is evident that the cement would fracture at a 0.07 % expansion, because the cement has about 7 to $9\;kgf/mm^2$ flexure strength. A turning point in the shear stress with mechanical load occurred at 0.02 % cement expansion. From an analysis of the porcelain body it is shown that there is sufficient margin of strength to guard against fracture of the porcelain body even for a cement expansion more than 0.12 %.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
• /
• pp.1031-1036
• /
• 2000

In this study, a numerical simulation that can effectively predict the strengthening effect of repaired aged RC structures is developed using the axial deformation link elements. In repaired structures, concrete and interface are modeled as quasi-brittle materials. An elastic-perfectly plastic constitutive relationship is introduced for reinforcing bars. Also, a linear-elastic relationship for repair materials such as FRP or CFS. Structural deterioration in terms of corrosion of steel rebar is considered. The interfacial property between steel and concrete which is reduced by corrosion of steel rebar is obtained by comparing numerical results with experimental results of pull out tests. Obtained values are used in repaired reinforced concrete structures under flexural loading conditions. To investigate strengthening effect of the structures repaired with carbon fiber sheet(CFS), repaired and unrepaired RC structures are analyzed numerically. From analysis, rip-off, debonding and rupture failure mechanisms of interface between substrate and CFS can be determined. Finally, strengthening effect according to the variation of interfacial material properties is investigated, and it is shown that interfacial material properties have influence on the mechanical behavior of repaired structure systems Therefore, the developed numerical method using axial deformation link elements can use for determining the strengthening effects and failure mechanism of repaired aged RC structure.

• 한국전기전자재료학회논문지
• /
• 제16권9호
• /
• pp.842-850
• /
• 2003

The suspension insulators are subjected to harsh environments in service for a long time. The long-term reliability of tile insulators is required for both mechanical and electrical performances. This study describes some basic performance tests and accelerated aging test by cool-heat cycling methods and thermal mechanical performance test methods on alumina porcelain insulators (new and aged) used for transmission line in KOREA. There was no fail in electrical and mechanical performance tests such as a high voltage strength, a flashover voltage, and an impact strength in all samples. But in the case of accelerating aging tests which have above 9$0^{\circ}C$ temperature gradient, fracture phenomena was happened by a thermal shock in tile aged sample(sample A) with low alumina porcelain body. It was indicated that sample A was more severely aged than other samples. According to results of HRB test and microstructural analysis, it was reasoned that insulator bodies with the matrix reinforced with alumina crystalline phase have advantages over the suppression of crack advance. And cool-heat aging and mechanical thermal ageing tests shows that a temperature gradient is more effective to accelerating than a cycling number.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 추계학술대회 논문집
• /
• pp.286-286
• /
• 2009

According to previous report, aged sleeves for old transmission lines have various defect such as biased installation or corrosion of steel sleeve. These defects can cause serious accidents such as rapid increasing of sag or falling out of overhead conductor from sleeves. Moreover, the defects have been limited power capacity of transmission line. This paper study on mechanical and thermal behavior of ACSR $410mm^2$ conductor and sleeve with various defect model. The conductor has been aged artificially for 50 years. The detailed results were presented in the text.

• 한국안전학회지
• /
• 제31권4호
• /
• pp.22-26
• /
• 2016

"Always-on" small ventilators are likely to experience thermal decomposition of insulating material due to thermal, electrical, mechanical and environmental influences, and lose insulating properties by the process of oxidation and physiochemical reaction. This increases the risk of electrical fire because of layer short, short circuit, overload and Plastics are usually used to make ventilator and ventilator enclosures since they make less noise and are cheaper. Although more preferred than iron, plastic, a combustible material, has a higher risk of fire. In this study, several experiments were carried out to find out how RCD(Residual Current Protective Device) and Thermal fuses, which are electric motor protection devices, work and what needs to be done to reduce the risk of fire.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
• /
• pp.130-134
• /
• 1997

The structural defects, impurities, degree of crosslinking and shrinkage of 38 field-aged distribution cables have been analyzed. For the comparison of data, 9 new cables were also subjected to an analysis. It is observed that the structural defects and degree of crosslinking show a radial profile. The structural defects are different depending on the manufacturer. A large amount of impurities is present in the insulation shield, which hold true for the new cables manufactured recently. The degree of crosslinking near both shields is lower than that at the central region of the insulation layer. It was also found that, in some cal)toes, the ins난lation was not fully crosslinked. The shrinkage of field-aged cables is higher than that of new cables.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
• /
• pp.326-329
• /
• 1997

The surface of mica/epoxy paper(130${\mu}{\textrm}{m}$) is investigated with SEM(scanning electron microscope). SEM micrographs revealed that thermal aging has a strong influence on aged specimens. The mica/epoxy paper was exposed at 187$^{\circ}C$ in an ordinary electrical oven for 72hour. Stater windings from two generators were measured by tan delta(tan $\delta$)and maximum partial discharge(Qm). The values of tan $\delta$and Qm were fecund to be higher for new generator than old one. The insulation condition of mica/epoxy paper were measured by ac current and tan $\delta$. Test results are observed that the sound specimens are higher than those aged. Model bar coils subjected to various accelerated agings were evaluated by Qm.