• 한국구조물진단유지관리공학회 논문집
• /
• 제6권2호
• /
• pp.255-261
• /
• 2002

Concrete structures stand in poor surrounding than it has ever been met before, because they are installed in severe conditions such as chloride penetration. $CO_2$ gas, water and so on. Therefore, the countermeasure to efficiently protect from the deterioration of concrete structures should be urgently considered. From this point of view, this study was aimed to develop surface treatment systems for concrete structures, which cover physical properties, long term durability and economic consideration. Developing the optimal surface treatment materials, powder type polymer or liquid type polymer was added to inorganic base materials. Three surface treatment materials which had shown best results in primary tests were selected and durability tests were fulfilled. Consequently optimum surface treatment material was developed. The surface treatment materials, which were developed through this study, can efficiently extend the service life of concrete structures. As a result, the life cycle cost should be reduced and the waste of material resources would be cut down.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2018년도 추계학술대회
• /
• pp.128-129
• /
• 2018

우리나라는 최근들어 급속한 고령화 사회로 진입하고 있다. 고령화 사회로 인한 노인들의 문제는 여러 분야에서 나타나게 된다. 신체적 취약점으로 인한 문제 뿐 아니라 인지적 저하로 인한 문제 역시 많은 문제가 발생하게 된다. 인지적 저하는 노인들의 일상생활을 수행하는데 어려움을 야기시키게 되며 이로인한 노인들의 삶의 질 역시 부정적으로 나타나게 된다. 본 연구에서는 인지적 저하 노인들을 대상으로 일상생활 수행이 원활하게 이루어질 수 있는 금융관련 교육콘텐츠를 개발하기 위한 사용자 분석을 실시하고자 한다. 이를 통해 인지저하가 나타날 수 있는 대표적 노인 사례를 개발하고 이를 기반으로 금융관련 교육콘텐츠 개발의 기반을 마련하고자 한다.

• 대한기계학회논문집B
• /
• 제28권11호
• /
• pp.1302-1314
• /
• 2004

Turbulent heat transfer to $CO_2$ at supercritical pressure flowing in vertical tubes is investigated using direct numerical simulation (DNS). A conservative space-time discretization scheme for variable-density flows at low Mach numbers is adopted in the present study to treat steep variations of fluid properties at supercritical pressure just above the thermodynamic critical point. The fluid properties at these conditions are obtained using PROPATH and used in the form of tables in the simulations. The buoyancy influence induced by strong variation of density across the pseudo-critical temperature proved to play a major role in turbulent heat transfer at supercritical state. Depending on the degree of buoyancy influence, turbulent heat transfer may be enhanced or significantly deteriorated, resulting in local hot spots along the heated surface. Based on the results of the present DNS combined with theoretical considerations, the physical mechanism of this local heat transfer deterioration is elucidated.

• Advances in concrete construction
• /
• 제12권5호
• /
• pp.411-418
• /
• 2021

Roller compacted concrete (RCC) used in the island reef airport runway will be subjected to the coupling actions of the fatigue impacts and the salt spray cycles, which will accelerate the deterioration of runway concrete and even threaten the flight safety. A cyclic impact testing machine and a climatic chamber were used to simulate the low-velocity fatigue impact and the salt spray cycles, respectively. The physical properties, the microstructures and the porosity of RCC were investigated. The results show the flexural strength firstly increases and then decreases with the increase of the fatigue impacts and the salt spray cycles. However, the decrease in the flexural strength is significantly earlier than the compressive strength of RCC only subjected to the salt spray cycles. The chlorine, sulfur and magnesium elements significantly increase in the pores of RCC subjected to 30000 fatigue impacts and 300 salt spray cycles, which causes the decrease in the porosity of RCC. The coupling effects of the fatigue impacts and the salt spray cycles in the later period accelerates the deterioration of RCC.

• Tuberculosis and Respiratory Diseases
• /
• 제85권4호
• /
• pp.289-301
• /
• 2022

Chronic obstructive pulmonary disease (COPD) is a chronic airway inflammation characterized by fixed airflow limitation and chronic respiratory symptoms, such as cough, sputum, and dyspnea. COPD is a progressive disease characterized by a decline in lung function. During the natural course of the disease, acute deterioration of symptoms leading to hospital visits can occur and influence further disease progression and subsequent exacerbation. Moreover, COPD is not only restricted to pulmonary manifestations but can present with other systemic diseases as comorbidities or systemic manifestations, including lung cancer, cardiovascular disease, pulmonary hypertension, sarcopenia, and metabolic abnormalities. These pulmonary and extrapulmonary conditions lead to the aggravation of dyspnea, physical inactivity, decreased exercise capacity, functional decline, reduced quality of life, and increased mortality. In addition, pneumonia, which is attributed to both COPD itself and an adverse effect of treatment (especially the use of inhaled and/or systemic steroids), can occur and lead to further deterioration in the prognosis of COPD. This review summarizes the long-term outcomes of patients with COPD. In addition, recent studies on the prediction of adverse outcomes are summarized in the last part of the review.

• 한국세라믹학회지
• /
• 제53권4호
• /
• pp.435-443
• /
• 2016

Coal ash, a material generated from coal-fired power plants, can be classified as fly ash and bottom ash. The amount of domestic fly ash generation is almost 6.84 million tons per year, while the amount of bottom ash generation is 1.51 million tons. The fly ash is commonly used as a concrete admixture and a subsidiary raw material in cement fabrication process. And some amount of bottom ash is used as a material for embankment and block. However, the recyclable amount of the ash is limited since it could cause deterioration of physical properties. In Korea, the ashes are simply mixed and used as a replacement material for cement. In this study, an attempt was made to mechanically activate the ash by grinding process in order to increase recycling rates of the fly ash. Activated fly ash was prepared by controlling the mill types and the milling times and characteristics of the mortar containing the activated fly ash was analyzed. When the ash was ground by using a vibratory mill, physical properties of the mortar mixed with such fly ash were higher than the mortar mixed with fly ash ground by a planetary mill.

• 펄프종이기술
• /
• 제34권1호
• /
• pp.46-53
• /
• 2002

This study was carried out to analyze the effects of preservation temperature and relative humidity to the physical properties of corrugated fiberboard boxes for fruit and vegetable packaging. The preservation temperature did not affect severely to physical properties of corrugated fiber-board. Relative humidity was a major cause of corrugated fiberboard box quality deterioration. The burst and compressive strengths of experimental boxes measured with Mullen high pressure tester and tong crush tester were decreased gradually as relative humidity increased from 55% to 75%. But, the strength properties slightly decreased relative humidity at 75% or higher. This tendency was the greater for single wall (SW) corrugated fiberboard box than that for double wall (DW). It is suggested that development of the water-resistant corrugated fiberboard and box be needed that can be used under the condition of low temperature and high moisture content, which are being employed in the cold chain system.

• 폴리머
• /
• 제27권3호
• /
• pp.169-175
• /
• 2003

무독성의 반응형 난연 도료를 제조할 목적으로 모체수지 1개의 구조단위 속에 2개의 인산기를 보유한 파이로포스포릭 락톤 변성 폴리에스터 (PATT)를 합성하고, PATT에 이소시아네이트인 toluene diisocyanate-isocyanurate를 상온경화시켜 2성분계 폴리우레탄 난연 도료(PIPUC)를 제조하였다. PIPUC로서 도막제작 후 비난연 도료와의 도막물성을 비교한 결과 난연 성분 도입에 따른 난연 도료의 물성이 저하되지 않음을 알았다. 난연성 시험 중 45$^{\circ}$ Meckel burner 법에서는 탄화길이가 3.1~4.4 cm를, LOI법에서는 LOI 27~30%를 각각 나타냄으로써 양호한 난연 효과를 보여주었고, SEM에 의한 표면 도막을 관찰한 결과 도막의 결함이나 상분리 현상이 생기지 않음을 관찰하였다.

• KIEAE Journal
• /
• 제9권3호
• /
• pp.47-59
• /
• 2009

In Korea has been supplied a large quantities of apartments since 1970s. The deteriorated middle-rise apartments of 1970s' have been rebuilt. It isn't lucrative to reconstruct the high-rise Apartment estates of the early 1990s' new towns in the capital area. Therefore the sustainable regeneration strategies of them have to be found. This research have been focused on the social and economical changes based on demography and the turning of technology and paradigm, the cities competitiveness compared with 2nd era new towns, physical deterioration of themselves. In these aspects, high-rise apartment estates in the 1st new towns face to 10 challenges such as an aging society, a multicultural society, U-city, an environmentally-friendly situation, the cities competitiveness of social, conomical and physical environment, the declining of estates, buildings and units. This study analyzed problems of 1st new town apartment estates and suggested regeneration tasks in accordence with those problems. The tasks are as follows. To accommodate the 1st new town apartment estates to social changes, they need to have a variety of community facilities and units, an opportunity of esidents participation. to establish a self-sufficient economy, a community usiness has to be vitalized and an ecological environment, an infrastructure of u-city and an improvement of physical environment obtained.

• 한국농촌건축학회논문집
• /
• 제17권1호
• /
• pp.1-8
• /
• 2015

The purpose of this study is to consider activation methods of traditional markets in Jinju city through questionnaire and field survey. Research framework is summarized into two categories: physical environment and operation program. The results are as follows: 1) the gross profit on sales has been decreased continuously and the main causes of that have been recognized as insufficiency of parking lots and convenient facilities and deterioration of environment in spite of facilities modernization project; 2) consumers visited a traditional market because of proper price and reliance on goods, etc. However, they were not satisfied with the physical environment such as parking lots and resting spaces and the operation program such as cultural event and performance. In conclusion it was thought that activation methods of traditional market would be related to the improvement plan in the physical aspect such as parking lots, walkway, convenient and crime prevention facilities and in the operation program aspect such as cultural event, marketing, management consulting, information infrastructure, and delivery system.